BOSTON – For infants with HIV infection, baseline immune function and birth health appear to influence viral control after the discontinuation of antiretroviral therapy (ART), an analysis of data from the landmark CHER trial shows.

Among 183 children diagnosed with HIV between 6 and 12 weeks of age who were started on early, time-limited ART, longer time to viral rebound after treatment discontinuation was associated with higher baseline CD4 percentages, higher birth weight, and with achievement of viral suppression within 40 weeks of starting on ART, reported Man Chan, PhD, of the Medical Research Council clinical trials unit at University College London.

patrisyu/Thinkstock

The estimated cumulative probability of rebound was 70% at 2 months following ART interruption, 80% at 4 months, 94% at 6 months, and 99% at 8 months.

In multivariable analysis, factors significantly associated with longer time to viral rebound included higher baseline CD4 counts (P = .03), higher birth weight (P = .032), and viral suppression within 40 weeks of starting on ART (P = .028)

In contrast, there were no significant associations with other factors in the multivariate model, including sex, baseline viral load, baseline CD8 percentage, HIV stage, status of therapy to prevent mother-to-child transmission, age at ART initiation, length of therapy, or treatment center.

Sensitivity analyses of a few cases in which there was a 4-7 month gap between rebound and the last viral load below 400 copies/mL before rebound showed similar results, Dr. Chan noted.

The study was the U.S. National Institutes of Health. Dr. Chan reported having nothing to disclose.

SOURCE: Violari A et al. CROI 2018, Abstract 137

BOSTON – For infants with HIV infection, baseline immune function and birth health appear to influence viral control after the discontinuation of antiretroviral therapy (ART), an analysis of data from the landmark CHER trial shows.

Among 183 children diagnosed with HIV between 6 and 12 weeks of age who were started on early, time-limited ART, longer time to viral rebound after treatment discontinuation was associated with higher baseline CD4 percentages, higher birth weight, and with achievement of viral suppression within 40 weeks of starting on ART, reported Man Chan, PhD, of the Medical Research Council clinical trials unit at University College London.

patrisyu/Thinkstock

The estimated cumulative probability of rebound was 70% at 2 months following ART interruption, 80% at 4 months, 94% at 6 months, and 99% at 8 months.

In multivariable analysis, factors significantly associated with longer time to viral rebound included higher baseline CD4 counts (P = .03), higher birth weight (P = .032), and viral suppression within 40 weeks of starting on ART (P = .028)

In contrast, there were no significant associations with other factors in the multivariate model, including sex, baseline viral load, baseline CD8 percentage, HIV stage, status of therapy to prevent mother-to-child transmission, age at ART initiation, length of therapy, or treatment center.

Sensitivity analyses of a few cases in which there was a 4-7 month gap between rebound and the last viral load below 400 copies/mL before rebound showed similar results, Dr. Chan noted.

The study was the U.S. National Institutes of Health. Dr. Chan reported having nothing to disclose.

SOURCE: Violari A et al. CROI 2018, Abstract 137

BOSTON – For infants with HIV infection, baseline immune function and birth health appear to influence viral control after the discontinuation of antiretroviral therapy (ART), an analysis of data from the landmark CHER trial shows.

Among 183 children diagnosed with HIV between 6 and 12 weeks of age who were started on early, time-limited ART, longer time to viral rebound after treatment discontinuation was associated with higher baseline CD4 percentages, higher birth weight, and with achievement of viral suppression within 40 weeks of starting on ART, reported Man Chan, PhD, of the Medical Research Council clinical trials unit at University College London.

patrisyu/Thinkstock

The estimated cumulative probability of rebound was 70% at 2 months following ART interruption, 80% at 4 months, 94% at 6 months, and 99% at 8 months.

In multivariable analysis, factors significantly associated with longer time to viral rebound included higher baseline CD4 counts (P = .03), higher birth weight (P = .032), and viral suppression within 40 weeks of starting on ART (P = .028)

In contrast, there were no significant associations with other factors in the multivariate model, including sex, baseline viral load, baseline CD8 percentage, HIV stage, status of therapy to prevent mother-to-child transmission, age at ART initiation, length of therapy, or treatment center.

Sensitivity analyses of a few cases in which there was a 4-7 month gap between rebound and the last viral load below 400 copies/mL before rebound showed similar results, Dr. Chan noted.

The study was the U.S. National Institutes of Health. Dr. Chan reported having nothing to disclose.

SOURCE: Violari A et al. CROI 2018, Abstract 137

ABSTRACT

This work is a retrospective cohort study evaluating patients who had undergone third-generation cemented total knee arthroplasty (TKA) with prostheses (NexGen, Zimmer Biomet) utilizing posterior-stabilized (PS) and cruciate-retaining (CR) designs at a single center at their 15-year follow-up.

The purpose of this study is to determine the functional knee scores, reoperations, and long-term survivorship for patients with the NexGen Zimmer Biomet Knee system at the 15-year follow-up. In total, 99 patients who had undergone primary TKA were followed for 15 years.

At the 15-year follow-up, survivorship in both study groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups also showed similar functionality: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Reoperation rates were 2% for the PS group and 0% for the CR group (P = .38). No differences in any of the outcomes analyzed were observed between patients who had CR TKA and those who had undergone PS TKA.

Our study found no significant differences in functional outcomes between PS and CR NexGen knee implants. Patients treated by both methods showed excellent longevity and survivorship at the 15-year follow-up.

Continue to: Total knee arthroplasty...

Total knee arthroplasty (TKA) is an orthopedic procedure with increasing demand.¹ Over the past 2 decades, a surge in TKA implants has been observed. Of the available prosthetic designs, only a few implants with long-term follow-up have been reported.^2-9 The NexGen TKA system (Zimmer Biomet) has been shown to have excellent clinical and radiographic results at an intermediate follow-up term of 8 years.¹⁰ This system is a third-generation prosthetic design that was developed to improve problems seen with its predecessors, such as the Miller-Galante II system (Zimmer Biomet), the Insall-Burstein II system (Zimmer Biomet), and the Constrained Condylar Knee (Zimmer Biomet), which were mainly for patellar maltracking.^11-17 The NexGen TKA system is a fixed-bearing system designed to include an anatomic femoral trochlea with the option of cruciate-retaining (CR), posterior-stabilized (PS), or more constrained implants. This study evaluates the long-term success of the CR and PS NexGen TKA systems. Outcomes measured include functional knee scores and reoperation rates at the 15-year follow-up. Based on the measured outcomes, potential differences between the PS and CR implants from this system are cited.

MATERIAL AND METHODS

Between July 1995 and July 1997, 334 consecutive primary TKAs were performed on 287 patients at our institution. In total, 167 patients (186 knees) underwent posterior CR TKAs with the NexGen CR prosthesis (Zimmer Biomet), and 120 patients (148 knees) underwent PS TKAs using the NexGen Legacy PS prosthesis (Zimmer Biomet). This retrospective double cohort study was reviewed and approved by our Institutional Review Board. At the 15-year postoperative follow-up, 99 patients were available (Figure 1).

The CR and PS implants were used with similar frequencies by the surgeons who performed the procedures. Patients were not randomized into either the PS- or CR-implant teams; the final decision on implant selection was left to the operating surgeon’s discretion. However, in addition to standard indications for TKA (pain and disability associated with severe arthritic change seen on radiographs and refractory to conservative measures), absolute contraindications to the CR implant included severe combined deformity (flexion contraction >30° combined with a varus or valgus deformity >20°) or posterior cruciate ligament insufficiency (often associated with inflammatory arthritis).

The surgical technique for the CR and PS designs was identical, and included a median parapatellar approach, femoral rotational alignment perpendicular to the transepicondylar axis, measured resection of the flexion and extension gaps, intramedullary femoral alignment, and extramedullary tibial alignment. All components were cemented, and the patella of each patient was resurfaced. All patients received preoperative antibiotics that were continued for 48 hours postoperatively, and 4 weeks of anticoagulation with dose-adjusted warfarin to maintain an international normalized ratio of 1.5 to 2.0.

Patients were observed postoperatively at the 5- to 8-year and 15-year time points. The 5-year data were previously published in 2005 by Bozic and colleagues.¹⁰ Patients available for follow-up at the 15-year time-point were evaluated using the 100-point Hospital for Special Surgery (HSS) knee scoring system, which assigns up to 30 points for pain, 22 points for function, 18 points for range of motion, and 10 points each for quadricep strength, deformity, and instability. In addition, common medical conditions limiting patient activity were assessed; these included joint replacement; arthritis in another joint, the back, or spine; weakness or fatigue; breathing or heart ailments; and others.

Continue to: At the 15-year follow-up...

At the 15-year follow-up, patients were contacted via telephone to obtain their HSS knee scores. If patients were unavailable/unable to answer the questions asked, knee score information was collected from a first-degree relative or caretaker. Patients that could not be contacted by phone were sent a HSS knee score survey to their last known address. The online Social Security Death Index was queried for confirmation of death. If deceased, a first-degree relative was contacted for confirmation.

Survivorship was evaluated using revision for any reason and revision for aseptic loosening as separate endpoints via the Kaplan-Meier product-limit method, and the CR and PS TKA groups were compared using the log-rank test. The power of the study for detecting differences between the TKA groups was determined to be 80%, based on a moderate hazard ratio of 1.5, using the log-rank test. Differences between PS and CR TKAs were assessed using the Pearson chi-square test for knee pain and functional outcomes, Fisher’s exact test for patient limitations, such as joint replacement, and the non-parametric Mann Whitney U-test for median pain scores (Table 1). Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were performed to assess whether self-reported knee scores were significantly correlated with physician-based knee scores. Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation at 95% confidence intervals. Statistical analysis was conducted using IBM SPSS Statistics (version 21.0, IBM). Two-tailed P < .05 was considered statistically significant.

RESULTS

Of the 287 patients (334 knees) who had primary TKAs, 99 patients (121 knees; 75 CR and 46 PS) were available at the 15-year follow-up. A total of 155 patients (171 knees) died before the 15-year follow-up, and 33 (42 knees) were lost to follow-up (Figure 1). The functional status of the knees of patients who were lost to follow-up or who had died since the previous follow-up data were published is unknown.

Demographic and outcome data for the cohort of 121 TKAs (99 patients) are summarized in Table 2. The median age at surgery was 64 years, and 71% of the cohort was female.

At the 15-year follow-up, survivorship in both groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups were also similar functionally: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Approximately half of the patients in both groups (52% PS; 50% CR; P = .88) required walking support (canes or walkers) and nearly half of both groups (46% PS; 48% CR; P = .62) could walk <5 blocks or only short distances in their homes. In addition, 46% of the patients in both groups reported needing arm assistance to functionally rise from a chair (P = .43); 91% of the patients in both groups could also walk up and down stairs (P = .77). No statistical difference in the medical conditions limiting the patients in the 2 groups was found: joint replacement (2% PS; 6% CR; P = .71), arthritis in another joint (43% PS; 45% CR; P = .84), back or spine arthritis (31% PS; 33% CR; P = 1.00), weakness or fatigue (24% PS; 25% CR; P = 1.00), breathing or heart ailments (11% PS; 20% CR; P = .40), and other reasons (27% PS; 25% CR; P = 1.00). In addition, median self-reported knee scores were 95 and 93 points for the PS and CR groups, respectively (P = .55).

Continue to: Patients reported 2 complications...

Patients reported 2 complications since the previous 5- to 8-year follow-up, 1 in each group. The first case underwent a PS TKA that required open reduction internal fixation for a bilateral supracondylar peri-prosthesis femur fracture following a fall, which was subsequently complicated with infection and ultimately led to above-the-knee amputation. In the second case, a CR TKA patient experienced persistent swelling and knee instability. The patient followed up with a local orthopaedist, but to date, no reoperations on the knee have been reported.

Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were moderately correlated with physician-based knee scores (r_s = 0.42; P < .001).

Reoperation rates were 2% for PS and 0% for CR (P = .38). Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation and no significance difference between the PS and CR groups was revealed (log-rank test = 1.40, P = .24, Figure 2).

DISCUSSION

The success of TKA in pain relief and restoration of function has led to increased demands for this surgery.¹ Such demand has enabled the introduction of a new joint replacement prosthesis to the market.¹⁸ Considering the increased incidence of osteoarthritis in the younger population (<55 years of age), critically reviewing the longevity and durability of TKA implant designs is of great importance. Compared with other TKA implant designs, the NexGen Zimmer Biomet Knee system has shown excellent longevity at the 15-year follow-up.^5,6,9,11-15 Our study began with 136 patients, and, after eliminating the deceased, those lost to follow-up, and non-responders, a total of 99 patients were available for the 15-year follow-up. At this time-point, 80% of the PS implants and 89% of the CR implants were associated with no or mild pain. Survivorship at the 15-year follow-up was similar in both groups: 98% for PS TKAs and 100% for CR TKAs. The reoperation rate was low in both groups, and no evidence of aseptic loosening was found. Based on our results, the NexGen Zimmer Biomet Knee system can be concluded to show excellent longevity and functional outcomes at the 15-year follow-up.

Our study includes several limiting factors that were taken into consideration during the analysis of the results. One of the main limitations of this work is that it required a 15-year follow-up of predominantly elderly patients; many of the participants may be expected to be deceased at this time-point. In our study, a total of 7 patients were confirmed to be deceased by a first-degree relative or the Social Security Death Index. In addition, unlike Bozic and colleagues’¹⁰ previous 5-year follow-up study, radiographic imaging data were not collected at the 15-year follow-up. However, given that this study aimed to assess the functional knee scores and reoperation rates of the PS and CR NexGen Zimmer Biomet Knee system, radiographic information did not appear to be necessary.

CONCLUSION

This study found no significant differences in functional outcomes between the PS and CR NexGen knee implants. Patients who received these implants showed excellent longevity and survivorship at their 15-year follow-up.

ABSTRACT

This work is a retrospective cohort study evaluating patients who had undergone third-generation cemented total knee arthroplasty (TKA) with prostheses (NexGen, Zimmer Biomet) utilizing posterior-stabilized (PS) and cruciate-retaining (CR) designs at a single center at their 15-year follow-up.

The purpose of this study is to determine the functional knee scores, reoperations, and long-term survivorship for patients with the NexGen Zimmer Biomet Knee system at the 15-year follow-up. In total, 99 patients who had undergone primary TKA were followed for 15 years.

At the 15-year follow-up, survivorship in both study groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups also showed similar functionality: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Reoperation rates were 2% for the PS group and 0% for the CR group (P = .38). No differences in any of the outcomes analyzed were observed between patients who had CR TKA and those who had undergone PS TKA.

Our study found no significant differences in functional outcomes between PS and CR NexGen knee implants. Patients treated by both methods showed excellent longevity and survivorship at the 15-year follow-up.

Continue to: Total knee arthroplasty...

Total knee arthroplasty (TKA) is an orthopedic procedure with increasing demand.¹ Over the past 2 decades, a surge in TKA implants has been observed. Of the available prosthetic designs, only a few implants with long-term follow-up have been reported.^2-9 The NexGen TKA system (Zimmer Biomet) has been shown to have excellent clinical and radiographic results at an intermediate follow-up term of 8 years.¹⁰ This system is a third-generation prosthetic design that was developed to improve problems seen with its predecessors, such as the Miller-Galante II system (Zimmer Biomet), the Insall-Burstein II system (Zimmer Biomet), and the Constrained Condylar Knee (Zimmer Biomet), which were mainly for patellar maltracking.^11-17 The NexGen TKA system is a fixed-bearing system designed to include an anatomic femoral trochlea with the option of cruciate-retaining (CR), posterior-stabilized (PS), or more constrained implants. This study evaluates the long-term success of the CR and PS NexGen TKA systems. Outcomes measured include functional knee scores and reoperation rates at the 15-year follow-up. Based on the measured outcomes, potential differences between the PS and CR implants from this system are cited.

MATERIAL AND METHODS

Between July 1995 and July 1997, 334 consecutive primary TKAs were performed on 287 patients at our institution. In total, 167 patients (186 knees) underwent posterior CR TKAs with the NexGen CR prosthesis (Zimmer Biomet), and 120 patients (148 knees) underwent PS TKAs using the NexGen Legacy PS prosthesis (Zimmer Biomet). This retrospective double cohort study was reviewed and approved by our Institutional Review Board. At the 15-year postoperative follow-up, 99 patients were available (Figure 1).

The CR and PS implants were used with similar frequencies by the surgeons who performed the procedures. Patients were not randomized into either the PS- or CR-implant teams; the final decision on implant selection was left to the operating surgeon’s discretion. However, in addition to standard indications for TKA (pain and disability associated with severe arthritic change seen on radiographs and refractory to conservative measures), absolute contraindications to the CR implant included severe combined deformity (flexion contraction >30° combined with a varus or valgus deformity >20°) or posterior cruciate ligament insufficiency (often associated with inflammatory arthritis).

The surgical technique for the CR and PS designs was identical, and included a median parapatellar approach, femoral rotational alignment perpendicular to the transepicondylar axis, measured resection of the flexion and extension gaps, intramedullary femoral alignment, and extramedullary tibial alignment. All components were cemented, and the patella of each patient was resurfaced. All patients received preoperative antibiotics that were continued for 48 hours postoperatively, and 4 weeks of anticoagulation with dose-adjusted warfarin to maintain an international normalized ratio of 1.5 to 2.0.

Patients were observed postoperatively at the 5- to 8-year and 15-year time points. The 5-year data were previously published in 2005 by Bozic and colleagues.¹⁰ Patients available for follow-up at the 15-year time-point were evaluated using the 100-point Hospital for Special Surgery (HSS) knee scoring system, which assigns up to 30 points for pain, 22 points for function, 18 points for range of motion, and 10 points each for quadricep strength, deformity, and instability. In addition, common medical conditions limiting patient activity were assessed; these included joint replacement; arthritis in another joint, the back, or spine; weakness or fatigue; breathing or heart ailments; and others.

Continue to: At the 15-year follow-up...

At the 15-year follow-up, patients were contacted via telephone to obtain their HSS knee scores. If patients were unavailable/unable to answer the questions asked, knee score information was collected from a first-degree relative or caretaker. Patients that could not be contacted by phone were sent a HSS knee score survey to their last known address. The online Social Security Death Index was queried for confirmation of death. If deceased, a first-degree relative was contacted for confirmation.

Survivorship was evaluated using revision for any reason and revision for aseptic loosening as separate endpoints via the Kaplan-Meier product-limit method, and the CR and PS TKA groups were compared using the log-rank test. The power of the study for detecting differences between the TKA groups was determined to be 80%, based on a moderate hazard ratio of 1.5, using the log-rank test. Differences between PS and CR TKAs were assessed using the Pearson chi-square test for knee pain and functional outcomes, Fisher’s exact test for patient limitations, such as joint replacement, and the non-parametric Mann Whitney U-test for median pain scores (Table 1). Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were performed to assess whether self-reported knee scores were significantly correlated with physician-based knee scores. Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation at 95% confidence intervals. Statistical analysis was conducted using IBM SPSS Statistics (version 21.0, IBM). Two-tailed P < .05 was considered statistically significant.

RESULTS

Of the 287 patients (334 knees) who had primary TKAs, 99 patients (121 knees; 75 CR and 46 PS) were available at the 15-year follow-up. A total of 155 patients (171 knees) died before the 15-year follow-up, and 33 (42 knees) were lost to follow-up (Figure 1). The functional status of the knees of patients who were lost to follow-up or who had died since the previous follow-up data were published is unknown.

Demographic and outcome data for the cohort of 121 TKAs (99 patients) are summarized in Table 2. The median age at surgery was 64 years, and 71% of the cohort was female.

At the 15-year follow-up, survivorship in both groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups were also similar functionally: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Approximately half of the patients in both groups (52% PS; 50% CR; P = .88) required walking support (canes or walkers) and nearly half of both groups (46% PS; 48% CR; P = .62) could walk <5 blocks or only short distances in their homes. In addition, 46% of the patients in both groups reported needing arm assistance to functionally rise from a chair (P = .43); 91% of the patients in both groups could also walk up and down stairs (P = .77). No statistical difference in the medical conditions limiting the patients in the 2 groups was found: joint replacement (2% PS; 6% CR; P = .71), arthritis in another joint (43% PS; 45% CR; P = .84), back or spine arthritis (31% PS; 33% CR; P = 1.00), weakness or fatigue (24% PS; 25% CR; P = 1.00), breathing or heart ailments (11% PS; 20% CR; P = .40), and other reasons (27% PS; 25% CR; P = 1.00). In addition, median self-reported knee scores were 95 and 93 points for the PS and CR groups, respectively (P = .55).

Continue to: Patients reported 2 complications...

Patients reported 2 complications since the previous 5- to 8-year follow-up, 1 in each group. The first case underwent a PS TKA that required open reduction internal fixation for a bilateral supracondylar peri-prosthesis femur fracture following a fall, which was subsequently complicated with infection and ultimately led to above-the-knee amputation. In the second case, a CR TKA patient experienced persistent swelling and knee instability. The patient followed up with a local orthopaedist, but to date, no reoperations on the knee have been reported.

Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were moderately correlated with physician-based knee scores (r_s = 0.42; P < .001).

Reoperation rates were 2% for PS and 0% for CR (P = .38). Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation and no significance difference between the PS and CR groups was revealed (log-rank test = 1.40, P = .24, Figure 2).

DISCUSSION

The success of TKA in pain relief and restoration of function has led to increased demands for this surgery.¹ Such demand has enabled the introduction of a new joint replacement prosthesis to the market.¹⁸ Considering the increased incidence of osteoarthritis in the younger population (<55 years of age), critically reviewing the longevity and durability of TKA implant designs is of great importance. Compared with other TKA implant designs, the NexGen Zimmer Biomet Knee system has shown excellent longevity at the 15-year follow-up.^5,6,9,11-15 Our study began with 136 patients, and, after eliminating the deceased, those lost to follow-up, and non-responders, a total of 99 patients were available for the 15-year follow-up. At this time-point, 80% of the PS implants and 89% of the CR implants were associated with no or mild pain. Survivorship at the 15-year follow-up was similar in both groups: 98% for PS TKAs and 100% for CR TKAs. The reoperation rate was low in both groups, and no evidence of aseptic loosening was found. Based on our results, the NexGen Zimmer Biomet Knee system can be concluded to show excellent longevity and functional outcomes at the 15-year follow-up.

Our study includes several limiting factors that were taken into consideration during the analysis of the results. One of the main limitations of this work is that it required a 15-year follow-up of predominantly elderly patients; many of the participants may be expected to be deceased at this time-point. In our study, a total of 7 patients were confirmed to be deceased by a first-degree relative or the Social Security Death Index. In addition, unlike Bozic and colleagues’¹⁰ previous 5-year follow-up study, radiographic imaging data were not collected at the 15-year follow-up. However, given that this study aimed to assess the functional knee scores and reoperation rates of the PS and CR NexGen Zimmer Biomet Knee system, radiographic information did not appear to be necessary.

CONCLUSION

This study found no significant differences in functional outcomes between the PS and CR NexGen knee implants. Patients who received these implants showed excellent longevity and survivorship at their 15-year follow-up.

ABSTRACT

This work is a retrospective cohort study evaluating patients who had undergone third-generation cemented total knee arthroplasty (TKA) with prostheses (NexGen, Zimmer Biomet) utilizing posterior-stabilized (PS) and cruciate-retaining (CR) designs at a single center at their 15-year follow-up.

The purpose of this study is to determine the functional knee scores, reoperations, and long-term survivorship for patients with the NexGen Zimmer Biomet Knee system at the 15-year follow-up. In total, 99 patients who had undergone primary TKA were followed for 15 years.

At the 15-year follow-up, survivorship in both study groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups also showed similar functionality: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Reoperation rates were 2% for the PS group and 0% for the CR group (P = .38). No differences in any of the outcomes analyzed were observed between patients who had CR TKA and those who had undergone PS TKA.

Our study found no significant differences in functional outcomes between PS and CR NexGen knee implants. Patients treated by both methods showed excellent longevity and survivorship at the 15-year follow-up.

Continue to: Total knee arthroplasty...

Total knee arthroplasty (TKA) is an orthopedic procedure with increasing demand.¹ Over the past 2 decades, a surge in TKA implants has been observed. Of the available prosthetic designs, only a few implants with long-term follow-up have been reported.^2-9 The NexGen TKA system (Zimmer Biomet) has been shown to have excellent clinical and radiographic results at an intermediate follow-up term of 8 years.¹⁰ This system is a third-generation prosthetic design that was developed to improve problems seen with its predecessors, such as the Miller-Galante II system (Zimmer Biomet), the Insall-Burstein II system (Zimmer Biomet), and the Constrained Condylar Knee (Zimmer Biomet), which were mainly for patellar maltracking.^11-17 The NexGen TKA system is a fixed-bearing system designed to include an anatomic femoral trochlea with the option of cruciate-retaining (CR), posterior-stabilized (PS), or more constrained implants. This study evaluates the long-term success of the CR and PS NexGen TKA systems. Outcomes measured include functional knee scores and reoperation rates at the 15-year follow-up. Based on the measured outcomes, potential differences between the PS and CR implants from this system are cited.

MATERIAL AND METHODS

Between July 1995 and July 1997, 334 consecutive primary TKAs were performed on 287 patients at our institution. In total, 167 patients (186 knees) underwent posterior CR TKAs with the NexGen CR prosthesis (Zimmer Biomet), and 120 patients (148 knees) underwent PS TKAs using the NexGen Legacy PS prosthesis (Zimmer Biomet). This retrospective double cohort study was reviewed and approved by our Institutional Review Board. At the 15-year postoperative follow-up, 99 patients were available (Figure 1).

The CR and PS implants were used with similar frequencies by the surgeons who performed the procedures. Patients were not randomized into either the PS- or CR-implant teams; the final decision on implant selection was left to the operating surgeon’s discretion. However, in addition to standard indications for TKA (pain and disability associated with severe arthritic change seen on radiographs and refractory to conservative measures), absolute contraindications to the CR implant included severe combined deformity (flexion contraction >30° combined with a varus or valgus deformity >20°) or posterior cruciate ligament insufficiency (often associated with inflammatory arthritis).

The surgical technique for the CR and PS designs was identical, and included a median parapatellar approach, femoral rotational alignment perpendicular to the transepicondylar axis, measured resection of the flexion and extension gaps, intramedullary femoral alignment, and extramedullary tibial alignment. All components were cemented, and the patella of each patient was resurfaced. All patients received preoperative antibiotics that were continued for 48 hours postoperatively, and 4 weeks of anticoagulation with dose-adjusted warfarin to maintain an international normalized ratio of 1.5 to 2.0.

Patients were observed postoperatively at the 5- to 8-year and 15-year time points. The 5-year data were previously published in 2005 by Bozic and colleagues.¹⁰ Patients available for follow-up at the 15-year time-point were evaluated using the 100-point Hospital for Special Surgery (HSS) knee scoring system, which assigns up to 30 points for pain, 22 points for function, 18 points for range of motion, and 10 points each for quadricep strength, deformity, and instability. In addition, common medical conditions limiting patient activity were assessed; these included joint replacement; arthritis in another joint, the back, or spine; weakness or fatigue; breathing or heart ailments; and others.

Continue to: At the 15-year follow-up...

At the 15-year follow-up, patients were contacted via telephone to obtain their HSS knee scores. If patients were unavailable/unable to answer the questions asked, knee score information was collected from a first-degree relative or caretaker. Patients that could not be contacted by phone were sent a HSS knee score survey to their last known address. The online Social Security Death Index was queried for confirmation of death. If deceased, a first-degree relative was contacted for confirmation.

Survivorship was evaluated using revision for any reason and revision for aseptic loosening as separate endpoints via the Kaplan-Meier product-limit method, and the CR and PS TKA groups were compared using the log-rank test. The power of the study for detecting differences between the TKA groups was determined to be 80%, based on a moderate hazard ratio of 1.5, using the log-rank test. Differences between PS and CR TKAs were assessed using the Pearson chi-square test for knee pain and functional outcomes, Fisher’s exact test for patient limitations, such as joint replacement, and the non-parametric Mann Whitney U-test for median pain scores (Table 1). Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were performed to assess whether self-reported knee scores were significantly correlated with physician-based knee scores. Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation at 95% confidence intervals. Statistical analysis was conducted using IBM SPSS Statistics (version 21.0, IBM). Two-tailed P < .05 was considered statistically significant.

RESULTS

Of the 287 patients (334 knees) who had primary TKAs, 99 patients (121 knees; 75 CR and 46 PS) were available at the 15-year follow-up. A total of 155 patients (171 knees) died before the 15-year follow-up, and 33 (42 knees) were lost to follow-up (Figure 1). The functional status of the knees of patients who were lost to follow-up or who had died since the previous follow-up data were published is unknown.

Demographic and outcome data for the cohort of 121 TKAs (99 patients) are summarized in Table 2. The median age at surgery was 64 years, and 71% of the cohort was female.

At the 15-year follow-up, survivorship in both groups was similar: 98% for PS TKAs and 100% for CR TKAs. The 2 groups were also similar functionally: 80% of the PS implants and 89% of the CR implants were associated with no or mild pain (P = .40). Approximately half of the patients in both groups (52% PS; 50% CR; P = .88) required walking support (canes or walkers) and nearly half of both groups (46% PS; 48% CR; P = .62) could walk <5 blocks or only short distances in their homes. In addition, 46% of the patients in both groups reported needing arm assistance to functionally rise from a chair (P = .43); 91% of the patients in both groups could also walk up and down stairs (P = .77). No statistical difference in the medical conditions limiting the patients in the 2 groups was found: joint replacement (2% PS; 6% CR; P = .71), arthritis in another joint (43% PS; 45% CR; P = .84), back or spine arthritis (31% PS; 33% CR; P = 1.00), weakness or fatigue (24% PS; 25% CR; P = 1.00), breathing or heart ailments (11% PS; 20% CR; P = .40), and other reasons (27% PS; 25% CR; P = 1.00). In addition, median self-reported knee scores were 95 and 93 points for the PS and CR groups, respectively (P = .55).

Continue to: Patients reported 2 complications...

Patients reported 2 complications since the previous 5- to 8-year follow-up, 1 in each group. The first case underwent a PS TKA that required open reduction internal fixation for a bilateral supracondylar peri-prosthesis femur fracture following a fall, which was subsequently complicated with infection and ultimately led to above-the-knee amputation. In the second case, a CR TKA patient experienced persistent swelling and knee instability. The patient followed up with a local orthopaedist, but to date, no reoperations on the knee have been reported.

Spearman correlations between the patients’ self-reported knee scores (as a percentage of normal) and physician-based knee scores were moderately correlated with physician-based knee scores (r_s = 0.42; P < .001).

Reoperation rates were 2% for PS and 0% for CR (P = .38). Kaplan-Meier analysis was performed to evaluate time-related freedom from reoperation and no significance difference between the PS and CR groups was revealed (log-rank test = 1.40, P = .24, Figure 2).

DISCUSSION

The success of TKA in pain relief and restoration of function has led to increased demands for this surgery.¹ Such demand has enabled the introduction of a new joint replacement prosthesis to the market.¹⁸ Considering the increased incidence of osteoarthritis in the younger population (<55 years of age), critically reviewing the longevity and durability of TKA implant designs is of great importance. Compared with other TKA implant designs, the NexGen Zimmer Biomet Knee system has shown excellent longevity at the 15-year follow-up.^5,6,9,11-15 Our study began with 136 patients, and, after eliminating the deceased, those lost to follow-up, and non-responders, a total of 99 patients were available for the 15-year follow-up. At this time-point, 80% of the PS implants and 89% of the CR implants were associated with no or mild pain. Survivorship at the 15-year follow-up was similar in both groups: 98% for PS TKAs and 100% for CR TKAs. The reoperation rate was low in both groups, and no evidence of aseptic loosening was found. Based on our results, the NexGen Zimmer Biomet Knee system can be concluded to show excellent longevity and functional outcomes at the 15-year follow-up.

Our study includes several limiting factors that were taken into consideration during the analysis of the results. One of the main limitations of this work is that it required a 15-year follow-up of predominantly elderly patients; many of the participants may be expected to be deceased at this time-point. In our study, a total of 7 patients were confirmed to be deceased by a first-degree relative or the Social Security Death Index. In addition, unlike Bozic and colleagues’¹⁰ previous 5-year follow-up study, radiographic imaging data were not collected at the 15-year follow-up. However, given that this study aimed to assess the functional knee scores and reoperation rates of the PS and CR NexGen Zimmer Biomet Knee system, radiographic information did not appear to be necessary.

CONCLUSION

This study found no significant differences in functional outcomes between the PS and CR NexGen knee implants. Patients who received these implants showed excellent longevity and survivorship at their 15-year follow-up.

The Food and Drug Administration has approved Toujeo (insulin glargine 300 units/mL) Max SoloStar, a prefilled and disposable pen. This will be the highest capacity long-acting insulin pen to be available commercially, according to a company press release.

The Max SoloStar pen holds more than 900 units of insulin glargine and can provide up to 160 units/mL in a single injection, which may reduce the number of injections needed to deliver the necessary dosage to adults. Another benefit of the higher capacity is that the device will require fewer refills and the associated copays, which could potentially lower costs for patients, depending on their insurance coverage.

Sanofi

ilacy@mdedge.com

The Food and Drug Administration has approved Toujeo (insulin glargine 300 units/mL) Max SoloStar, a prefilled and disposable pen. This will be the highest capacity long-acting insulin pen to be available commercially, according to a company press release.

The Max SoloStar pen holds more than 900 units of insulin glargine and can provide up to 160 units/mL in a single injection, which may reduce the number of injections needed to deliver the necessary dosage to adults. Another benefit of the higher capacity is that the device will require fewer refills and the associated copays, which could potentially lower costs for patients, depending on their insurance coverage.

Sanofi

ilacy@mdedge.com

The Food and Drug Administration has approved Toujeo (insulin glargine 300 units/mL) Max SoloStar, a prefilled and disposable pen. This will be the highest capacity long-acting insulin pen to be available commercially, according to a company press release.

The Max SoloStar pen holds more than 900 units of insulin glargine and can provide up to 160 units/mL in a single injection, which may reduce the number of injections needed to deliver the necessary dosage to adults. Another benefit of the higher capacity is that the device will require fewer refills and the associated copays, which could potentially lower costs for patients, depending on their insurance coverage.

Sanofi

ilacy@mdedge.com

Sessile serrated polyps (SSPs), notorious for being difficult to detect and for their potential to become malignant colorectal tumors, appear to be caused by a single oncogenic mutation, a finding that could lead to better early detection of some colorectal cancers through noninvasive stool testing, investigators say.

Using a comprehensive battery of genomic testing and DNA methylation profiling, David Jones, PhD, of the Oklahoma Medical Research Foundation in Oklahoma City and his colleagues compared SSPs with familial adenomatous polyps (FAPs), and found that the V600E mutation in BRAF (V-Raf Murine Sarcoma Viral Oncogene Homolog B) was the sole cancer-causing mutation in SSPs.

They also found a distinct DNA methylation pattern unique to SSPs.

“These SSP-specific methylation patterns effectively distinguish SSP from adenomatous polyps, which could be important for both diagnosis and treatment. It also suggests that the BRAF-V600E mutation directly or indirectly results in the remodeling of the epigenome and that this may set a stage for tumor progression,” they wrote in the open-access journal PLOS One.

Approximately one-third of sporadic colorectal cancers, which account for about 95% of all colorectal malignancies, are thought to arise from premalignant serrated lesions, including SSPs, hyperplastic polyps, and traditional serrated adenomas, the authors noted.

Although SSPs and traditional serrated adenomas both have significant potential for malignant transformation, SSPs are much more common, making them important targets for research, diagnosis, and possible interventions.

“Previous surveys of cancer-associated mutations in SSP samples, through targeted analysis of limited known mutations, identified the BRAF-V600E as the key mutation in this disease. However, it is not clear whether other mutations in the same samples contribute to the etiology of this disease,” Dr. Jones and his associates wrote.

SOURCE: Dehghanizadeh S et al. PLOS One 13(3): e0192499.

Sessile serrated polyps (SSPs), notorious for being difficult to detect and for their potential to become malignant colorectal tumors, appear to be caused by a single oncogenic mutation, a finding that could lead to better early detection of some colorectal cancers through noninvasive stool testing, investigators say.

Using a comprehensive battery of genomic testing and DNA methylation profiling, David Jones, PhD, of the Oklahoma Medical Research Foundation in Oklahoma City and his colleagues compared SSPs with familial adenomatous polyps (FAPs), and found that the V600E mutation in BRAF (V-Raf Murine Sarcoma Viral Oncogene Homolog B) was the sole cancer-causing mutation in SSPs.

They also found a distinct DNA methylation pattern unique to SSPs.

“These SSP-specific methylation patterns effectively distinguish SSP from adenomatous polyps, which could be important for both diagnosis and treatment. It also suggests that the BRAF-V600E mutation directly or indirectly results in the remodeling of the epigenome and that this may set a stage for tumor progression,” they wrote in the open-access journal PLOS One.

Approximately one-third of sporadic colorectal cancers, which account for about 95% of all colorectal malignancies, are thought to arise from premalignant serrated lesions, including SSPs, hyperplastic polyps, and traditional serrated adenomas, the authors noted.

Although SSPs and traditional serrated adenomas both have significant potential for malignant transformation, SSPs are much more common, making them important targets for research, diagnosis, and possible interventions.

“Previous surveys of cancer-associated mutations in SSP samples, through targeted analysis of limited known mutations, identified the BRAF-V600E as the key mutation in this disease. However, it is not clear whether other mutations in the same samples contribute to the etiology of this disease,” Dr. Jones and his associates wrote.

SOURCE: Dehghanizadeh S et al. PLOS One 13(3): e0192499.

Sessile serrated polyps (SSPs), notorious for being difficult to detect and for their potential to become malignant colorectal tumors, appear to be caused by a single oncogenic mutation, a finding that could lead to better early detection of some colorectal cancers through noninvasive stool testing, investigators say.

Using a comprehensive battery of genomic testing and DNA methylation profiling, David Jones, PhD, of the Oklahoma Medical Research Foundation in Oklahoma City and his colleagues compared SSPs with familial adenomatous polyps (FAPs), and found that the V600E mutation in BRAF (V-Raf Murine Sarcoma Viral Oncogene Homolog B) was the sole cancer-causing mutation in SSPs.

They also found a distinct DNA methylation pattern unique to SSPs.

“These SSP-specific methylation patterns effectively distinguish SSP from adenomatous polyps, which could be important for both diagnosis and treatment. It also suggests that the BRAF-V600E mutation directly or indirectly results in the remodeling of the epigenome and that this may set a stage for tumor progression,” they wrote in the open-access journal PLOS One.

Approximately one-third of sporadic colorectal cancers, which account for about 95% of all colorectal malignancies, are thought to arise from premalignant serrated lesions, including SSPs, hyperplastic polyps, and traditional serrated adenomas, the authors noted.

Although SSPs and traditional serrated adenomas both have significant potential for malignant transformation, SSPs are much more common, making them important targets for research, diagnosis, and possible interventions.

“Previous surveys of cancer-associated mutations in SSP samples, through targeted analysis of limited known mutations, identified the BRAF-V600E as the key mutation in this disease. However, it is not clear whether other mutations in the same samples contribute to the etiology of this disease,” Dr. Jones and his associates wrote.

SOURCE: Dehghanizadeh S et al. PLOS One 13(3): e0192499.

The resurgence of whooping cough in the United States could be the result of waning pertussis immunity combined with incomplete historical coverage, researchers said.

In the March 28, 2018, edition of Science Translational Medicine, researchers reported on a study that used different models of transmission to explore what might be the cause of the steady increase in pertussis infections since the mid-1970s.

copyright CDC

“Our results suggest that the train of events leading to the resurgence of pertussis was set in motion well before the shift to the DTaP vaccine,” Dr. Domenech de Cellès and his associates said.

The model also pointed to big shifts in the age-specific immunological profile caused by introduction of vaccination, which led to a reduction in transmission and also a reduction in natural infections both in vaccinated and unvaccinated individuals.

This meant individuals who either did not get vaccinated as children or who did not gain immunity from vaccination were growing to adulthood without ever being exposed to natural infection.

“Concurrently, older cohorts, with their long-lived immunity derived from natural infections experienced during the prevaccine period, were gradually dying out,” the authors said. “The resulting rise in the number of susceptible adults sets the stage for the pertussis resurgence, especially among adults.”

Two authors were supported by the National Institutes of Health and by Models of Infectious Disease Agent Study–National Institute of General Medical Sciences. No conflicts of interest were declared.

SOURCE: Domenech de Cellès M et al. Sci Transl Med. 2018 Mar 28;10:eaaj1748.

The resurgence of whooping cough in the United States could be the result of waning pertussis immunity combined with incomplete historical coverage, researchers said.

In the March 28, 2018, edition of Science Translational Medicine, researchers reported on a study that used different models of transmission to explore what might be the cause of the steady increase in pertussis infections since the mid-1970s.

copyright CDC

“Our results suggest that the train of events leading to the resurgence of pertussis was set in motion well before the shift to the DTaP vaccine,” Dr. Domenech de Cellès and his associates said.

The model also pointed to big shifts in the age-specific immunological profile caused by introduction of vaccination, which led to a reduction in transmission and also a reduction in natural infections both in vaccinated and unvaccinated individuals.

This meant individuals who either did not get vaccinated as children or who did not gain immunity from vaccination were growing to adulthood without ever being exposed to natural infection.

“Concurrently, older cohorts, with their long-lived immunity derived from natural infections experienced during the prevaccine period, were gradually dying out,” the authors said. “The resulting rise in the number of susceptible adults sets the stage for the pertussis resurgence, especially among adults.”

Two authors were supported by the National Institutes of Health and by Models of Infectious Disease Agent Study–National Institute of General Medical Sciences. No conflicts of interest were declared.

SOURCE: Domenech de Cellès M et al. Sci Transl Med. 2018 Mar 28;10:eaaj1748.

The resurgence of whooping cough in the United States could be the result of waning pertussis immunity combined with incomplete historical coverage, researchers said.

In the March 28, 2018, edition of Science Translational Medicine, researchers reported on a study that used different models of transmission to explore what might be the cause of the steady increase in pertussis infections since the mid-1970s.

copyright CDC

“Our results suggest that the train of events leading to the resurgence of pertussis was set in motion well before the shift to the DTaP vaccine,” Dr. Domenech de Cellès and his associates said.

The model also pointed to big shifts in the age-specific immunological profile caused by introduction of vaccination, which led to a reduction in transmission and also a reduction in natural infections both in vaccinated and unvaccinated individuals.

This meant individuals who either did not get vaccinated as children or who did not gain immunity from vaccination were growing to adulthood without ever being exposed to natural infection.

“Concurrently, older cohorts, with their long-lived immunity derived from natural infections experienced during the prevaccine period, were gradually dying out,” the authors said. “The resulting rise in the number of susceptible adults sets the stage for the pertussis resurgence, especially among adults.”

Two authors were supported by the National Institutes of Health and by Models of Infectious Disease Agent Study–National Institute of General Medical Sciences. No conflicts of interest were declared.

SOURCE: Domenech de Cellès M et al. Sci Transl Med. 2018 Mar 28;10:eaaj1748.

BOSTON – Nanotechnology, though small in scale, is making a big difference in gastroenterology. Nanoparticles can deliver therapeutic compounds or enable other diagnostic tools, said Vadim Backman, PhD, the Walter Dill Scott Professor of Biomedical Engineering at Northwestern University, Chicago, in a video interview at the AGA Tech Summit, sponsored by the AGA Center for GI Innovation and Technology. Nanotechnology can treat disease by reprogramming gene expression or gene regulation. Nanoparticle formulations are FDA approved now for treatment of esophageal, colon, and pancreatic cancers, said Dr. Backman in a video interview, but the ability of nanotechnology to reprogram biological processes at the genetic level has researchers looking at treating inflammatory diseases and regenerating tissues.

lmcglade@mdedge.com

BOSTON – Nanotechnology, though small in scale, is making a big difference in gastroenterology. Nanoparticles can deliver therapeutic compounds or enable other diagnostic tools, said Vadim Backman, PhD, the Walter Dill Scott Professor of Biomedical Engineering at Northwestern University, Chicago, in a video interview at the AGA Tech Summit, sponsored by the AGA Center for GI Innovation and Technology. Nanotechnology can treat disease by reprogramming gene expression or gene regulation. Nanoparticle formulations are FDA approved now for treatment of esophageal, colon, and pancreatic cancers, said Dr. Backman in a video interview, but the ability of nanotechnology to reprogram biological processes at the genetic level has researchers looking at treating inflammatory diseases and regenerating tissues.

lmcglade@mdedge.com

BOSTON – Nanotechnology, though small in scale, is making a big difference in gastroenterology. Nanoparticles can deliver therapeutic compounds or enable other diagnostic tools, said Vadim Backman, PhD, the Walter Dill Scott Professor of Biomedical Engineering at Northwestern University, Chicago, in a video interview at the AGA Tech Summit, sponsored by the AGA Center for GI Innovation and Technology. Nanotechnology can treat disease by reprogramming gene expression or gene regulation. Nanoparticle formulations are FDA approved now for treatment of esophageal, colon, and pancreatic cancers, said Dr. Backman in a video interview, but the ability of nanotechnology to reprogram biological processes at the genetic level has researchers looking at treating inflammatory diseases and regenerating tissues.

lmcglade@mdedge.com

CHICAGO – When fat tissue from individuals with obesity was exposed to the artificial sweetener sucralose, there was significant upregulation of genes that promote intracellular glucose transport. Genes known to be adipogenic and those governing sweet taste receptors also were significantly upregulated with sucralose exposure.

“Effects of sucralose are particularly more detrimental in obese individuals who are prediabetic or diabetic, rather than nonobese consumers of low-calorie sweetener,” said Sabyasachi Sen, MD, during a press conference at the annual meeting of the Endocrine Society.

These new findings, together with in vitro examination of human adipose-derived mesenchymal stromal cells (MSCs) exposed to sucralose, are helping solve the puzzle of how a sweetener that delivers no energy may contribute to metabolic derangement, said Dr. Sen, professor of endocrinology at George Washington University in Washington.

Dr. Sen and his collaborators first exposed the MSCs to concentrations of sucralose ranging from 0 mM to 0.2 mM – a physiologic level for high sucralose consumers – to the supraphysiologic concentration of 1 mM.

The adipogenic genes CEBPa and FABP4 were upregulated in the sucralose-exposed MSCs, which also showed more intracellular fat droplet accumulation. Reactive oxygen species increased in the MSCs in a dose-dependent fashion as well, said Dr. Sen in a video interview.

All of this upregulation, said Dr. Sen, was pushing the MSCs toward becoming fat cells. “At the same time, we saw that there are certain genes that were upregulating that were allowing more glucose to enter the cell.” The increase in reactive oxygen species paralleled what was seen in a similar model that used glucose rather than sucralose, he said.

The investigators then took subcutaneous fat biopsies from four normal-weight individuals (body mass index, 23.4-24.8 kg/m²), and from 14 obese individuals (BMI, 32-64 kg/m²). Each group had sucralose users and nonusers. Using mRNA gene expression profiles, they saw that glucose transporter genes, adipogenic genes, and antioxidant genes were upregulated among sucralose consumers with obesity, significantly more than for the normal-weight participants.

koakes@mdedge.com

SOURCE: Sen S et al. ENDO 2018, Abstract SUN-071.

CHICAGO – When fat tissue from individuals with obesity was exposed to the artificial sweetener sucralose, there was significant upregulation of genes that promote intracellular glucose transport. Genes known to be adipogenic and those governing sweet taste receptors also were significantly upregulated with sucralose exposure.

“Effects of sucralose are particularly more detrimental in obese individuals who are prediabetic or diabetic, rather than nonobese consumers of low-calorie sweetener,” said Sabyasachi Sen, MD, during a press conference at the annual meeting of the Endocrine Society.

These new findings, together with in vitro examination of human adipose-derived mesenchymal stromal cells (MSCs) exposed to sucralose, are helping solve the puzzle of how a sweetener that delivers no energy may contribute to metabolic derangement, said Dr. Sen, professor of endocrinology at George Washington University in Washington.

Dr. Sen and his collaborators first exposed the MSCs to concentrations of sucralose ranging from 0 mM to 0.2 mM – a physiologic level for high sucralose consumers – to the supraphysiologic concentration of 1 mM.

The adipogenic genes CEBPa and FABP4 were upregulated in the sucralose-exposed MSCs, which also showed more intracellular fat droplet accumulation. Reactive oxygen species increased in the MSCs in a dose-dependent fashion as well, said Dr. Sen in a video interview.

All of this upregulation, said Dr. Sen, was pushing the MSCs toward becoming fat cells. “At the same time, we saw that there are certain genes that were upregulating that were allowing more glucose to enter the cell.” The increase in reactive oxygen species paralleled what was seen in a similar model that used glucose rather than sucralose, he said.

The investigators then took subcutaneous fat biopsies from four normal-weight individuals (body mass index, 23.4-24.8 kg/m²), and from 14 obese individuals (BMI, 32-64 kg/m²). Each group had sucralose users and nonusers. Using mRNA gene expression profiles, they saw that glucose transporter genes, adipogenic genes, and antioxidant genes were upregulated among sucralose consumers with obesity, significantly more than for the normal-weight participants.

koakes@mdedge.com

SOURCE: Sen S et al. ENDO 2018, Abstract SUN-071.

CHICAGO – When fat tissue from individuals with obesity was exposed to the artificial sweetener sucralose, there was significant upregulation of genes that promote intracellular glucose transport. Genes known to be adipogenic and those governing sweet taste receptors also were significantly upregulated with sucralose exposure.

“Effects of sucralose are particularly more detrimental in obese individuals who are prediabetic or diabetic, rather than nonobese consumers of low-calorie sweetener,” said Sabyasachi Sen, MD, during a press conference at the annual meeting of the Endocrine Society.

These new findings, together with in vitro examination of human adipose-derived mesenchymal stromal cells (MSCs) exposed to sucralose, are helping solve the puzzle of how a sweetener that delivers no energy may contribute to metabolic derangement, said Dr. Sen, professor of endocrinology at George Washington University in Washington.

Dr. Sen and his collaborators first exposed the MSCs to concentrations of sucralose ranging from 0 mM to 0.2 mM – a physiologic level for high sucralose consumers – to the supraphysiologic concentration of 1 mM.

The adipogenic genes CEBPa and FABP4 were upregulated in the sucralose-exposed MSCs, which also showed more intracellular fat droplet accumulation. Reactive oxygen species increased in the MSCs in a dose-dependent fashion as well, said Dr. Sen in a video interview.

All of this upregulation, said Dr. Sen, was pushing the MSCs toward becoming fat cells. “At the same time, we saw that there are certain genes that were upregulating that were allowing more glucose to enter the cell.” The increase in reactive oxygen species paralleled what was seen in a similar model that used glucose rather than sucralose, he said.

The investigators then took subcutaneous fat biopsies from four normal-weight individuals (body mass index, 23.4-24.8 kg/m²), and from 14 obese individuals (BMI, 32-64 kg/m²). Each group had sucralose users and nonusers. Using mRNA gene expression profiles, they saw that glucose transporter genes, adipogenic genes, and antioxidant genes were upregulated among sucralose consumers with obesity, significantly more than for the normal-weight participants.

koakes@mdedge.com

SOURCE: Sen S et al. ENDO 2018, Abstract SUN-071.

Difficulties with sleep are prevalent and significant across the developmental spectrum. Not only does poor sleep affect daytime functioning in relation to mood, focus, appetite, and emotional regulation, but ineffective bedtime routines can cause significant distress for youth and caregivers, as well. The American Academy of Sleep Medicine describes insomnia as “repeated difficulty with sleep initiation, duration, consolidation, or quality that occurs despite age-appropriate time and opportunity for sleep and results in daytime functional impairment for the child and/or family.’’¹

Pediatric providers likely are familiar already with initial steps in the evaluation and treatment of insomnia. The emphasis here is assessment and intervention approaches beyond the foundational use of sleep hygiene recommendations.

tab1962/Thinkstock

In general, medications are considered when other appropriate interventions have proven inadequate. There is very little evidence for using pharmacologic interventions for pediatric insomnia, so even if a medication is selected, behavioral approaches should remain a mainstay.⁴ Patients and caregivers should agree to specific short-term goals ahead of time when using sleep medicine, given the limited effectiveness and recommended short duration of use. Many medications change sleep architecture, and none have been clearly shown to sustainably improve sleep quality or quantity or reduce daytime symptoms of insomnia.

Prescribing guidelines for insomnia suggest selecting an agent matched to the symptoms and relevant to any comorbidities. Melatonin may be most helpful in shifting the sleep phase rather than for direct hypnotic effects; thus adolescents or patients with ADHD whose sleep schedule has naturally shifted later may benefit from a small dose of melatonin (1-3 mg) several hours before bedtime to prime their system. Beware that melatonin is not regulated by the Food and Drug Administration and animal studies have shown significant alterations of the gonadal hormone axis, although this has not been examined in human trials. Alpha-2 agonists – such as clonidine and guanfacine – may be helpful for sleep initiation, especially in populations with comorbid ADHD, aggression, or tics, where these medications might be otherwise indicated. Prazosin, an alpha-1 antagonist, has some limited evidence as a treatment for nightmares and PTSD symptoms, so it may be a good choice for children with trauma-related hypervigilance.

In patients with depression, low doses of trazodone (12.5-50 mg) or mirtazapine (7.5-15 mg) may be effective. Although short-acting benzodiazepines may be useful in the short-term, particularly for sleep-onset difficulties, they generally are not recommended because of the risks of abuse, diversion, withdrawal, cognitive side effects, disinhibition, development of tolerance, and contraindication with such comorbidities as sleep apnea. However, the benzodiazepine receptor agonists such as zaleplon, zolpidem, and eszopiclone, while lacking evidence in the pediatric population, may be worthwhile considerations as their varying half-lives allow for specificity in treating sleep-onset vs. sleep-maintenance problems. Caregivers should be warned about the potential for sleepwalking or other complex sleep-related behaviors with this class of medicines.

Avoid tricyclic antidepressants because of the potential for anticholinergic effects and cardiotoxicity. Atypical antipsychotics generally are not worth the risk of serious and rapid side effects associated with this class of medications, which include metabolic syndrome.

Dr. Rosenfeld is assistant professor of psychiatry at Vermont Center for Children, Youth & Families, at the University of Vermont Medical Center, and the University of Vermont, Burlington. He has received honorarium from Oakstone Publishing for contributing board review course content on human development.

References

1. International Classification of Sleep Disorders: Diagnostic & Coding Manual. 2nd edition. (Westchester: American Academy of Sleep Medicine, 2005).

2. Child Adolesc Psychiatr Clin N Am. 2009 Oct;18(4):979-1000

3. J Child Psychol Psychiatry. 2017, Oct 20. doi: 10.1111/jcpp.12834.

4. Child Adolesc Psychiatric Clin N Am. 2009, Oct;18(4):1001-16.

Difficulties with sleep are prevalent and significant across the developmental spectrum. Not only does poor sleep affect daytime functioning in relation to mood, focus, appetite, and emotional regulation, but ineffective bedtime routines can cause significant distress for youth and caregivers, as well. The American Academy of Sleep Medicine describes insomnia as “repeated difficulty with sleep initiation, duration, consolidation, or quality that occurs despite age-appropriate time and opportunity for sleep and results in daytime functional impairment for the child and/or family.’’¹

Pediatric providers likely are familiar already with initial steps in the evaluation and treatment of insomnia. The emphasis here is assessment and intervention approaches beyond the foundational use of sleep hygiene recommendations.

tab1962/Thinkstock

In general, medications are considered when other appropriate interventions have proven inadequate. There is very little evidence for using pharmacologic interventions for pediatric insomnia, so even if a medication is selected, behavioral approaches should remain a mainstay.⁴ Patients and caregivers should agree to specific short-term goals ahead of time when using sleep medicine, given the limited effectiveness and recommended short duration of use. Many medications change sleep architecture, and none have been clearly shown to sustainably improve sleep quality or quantity or reduce daytime symptoms of insomnia.

Prescribing guidelines for insomnia suggest selecting an agent matched to the symptoms and relevant to any comorbidities. Melatonin may be most helpful in shifting the sleep phase rather than for direct hypnotic effects; thus adolescents or patients with ADHD whose sleep schedule has naturally shifted later may benefit from a small dose of melatonin (1-3 mg) several hours before bedtime to prime their system. Beware that melatonin is not regulated by the Food and Drug Administration and animal studies have shown significant alterations of the gonadal hormone axis, although this has not been examined in human trials. Alpha-2 agonists – such as clonidine and guanfacine – may be helpful for sleep initiation, especially in populations with comorbid ADHD, aggression, or tics, where these medications might be otherwise indicated. Prazosin, an alpha-1 antagonist, has some limited evidence as a treatment for nightmares and PTSD symptoms, so it may be a good choice for children with trauma-related hypervigilance.

In patients with depression, low doses of trazodone (12.5-50 mg) or mirtazapine (7.5-15 mg) may be effective. Although short-acting benzodiazepines may be useful in the short-term, particularly for sleep-onset difficulties, they generally are not recommended because of the risks of abuse, diversion, withdrawal, cognitive side effects, disinhibition, development of tolerance, and contraindication with such comorbidities as sleep apnea. However, the benzodiazepine receptor agonists such as zaleplon, zolpidem, and eszopiclone, while lacking evidence in the pediatric population, may be worthwhile considerations as their varying half-lives allow for specificity in treating sleep-onset vs. sleep-maintenance problems. Caregivers should be warned about the potential for sleepwalking or other complex sleep-related behaviors with this class of medicines.

Avoid tricyclic antidepressants because of the potential for anticholinergic effects and cardiotoxicity. Atypical antipsychotics generally are not worth the risk of serious and rapid side effects associated with this class of medications, which include metabolic syndrome.

Dr. Rosenfeld is assistant professor of psychiatry at Vermont Center for Children, Youth & Families, at the University of Vermont Medical Center, and the University of Vermont, Burlington. He has received honorarium from Oakstone Publishing for contributing board review course content on human development.

References

1. International Classification of Sleep Disorders: Diagnostic & Coding Manual. 2nd edition. (Westchester: American Academy of Sleep Medicine, 2005).

2. Child Adolesc Psychiatr Clin N Am. 2009 Oct;18(4):979-1000

3. J Child Psychol Psychiatry. 2017, Oct 20. doi: 10.1111/jcpp.12834.

4. Child Adolesc Psychiatric Clin N Am. 2009, Oct;18(4):1001-16.

Difficulties with sleep are prevalent and significant across the developmental spectrum. Not only does poor sleep affect daytime functioning in relation to mood, focus, appetite, and emotional regulation, but ineffective bedtime routines can cause significant distress for youth and caregivers, as well. The American Academy of Sleep Medicine describes insomnia as “repeated difficulty with sleep initiation, duration, consolidation, or quality that occurs despite age-appropriate time and opportunity for sleep and results in daytime functional impairment for the child and/or family.’’¹

Pediatric providers likely are familiar already with initial steps in the evaluation and treatment of insomnia. The emphasis here is assessment and intervention approaches beyond the foundational use of sleep hygiene recommendations.

tab1962/Thinkstock

In general, medications are considered when other appropriate interventions have proven inadequate. There is very little evidence for using pharmacologic interventions for pediatric insomnia, so even if a medication is selected, behavioral approaches should remain a mainstay.⁴ Patients and caregivers should agree to specific short-term goals ahead of time when using sleep medicine, given the limited effectiveness and recommended short duration of use. Many medications change sleep architecture, and none have been clearly shown to sustainably improve sleep quality or quantity or reduce daytime symptoms of insomnia.

Prescribing guidelines for insomnia suggest selecting an agent matched to the symptoms and relevant to any comorbidities. Melatonin may be most helpful in shifting the sleep phase rather than for direct hypnotic effects; thus adolescents or patients with ADHD whose sleep schedule has naturally shifted later may benefit from a small dose of melatonin (1-3 mg) several hours before bedtime to prime their system. Beware that melatonin is not regulated by the Food and Drug Administration and animal studies have shown significant alterations of the gonadal hormone axis, although this has not been examined in human trials. Alpha-2 agonists – such as clonidine and guanfacine – may be helpful for sleep initiation, especially in populations with comorbid ADHD, aggression, or tics, where these medications might be otherwise indicated. Prazosin, an alpha-1 antagonist, has some limited evidence as a treatment for nightmares and PTSD symptoms, so it may be a good choice for children with trauma-related hypervigilance.

In patients with depression, low doses of trazodone (12.5-50 mg) or mirtazapine (7.5-15 mg) may be effective. Although short-acting benzodiazepines may be useful in the short-term, particularly for sleep-onset difficulties, they generally are not recommended because of the risks of abuse, diversion, withdrawal, cognitive side effects, disinhibition, development of tolerance, and contraindication with such comorbidities as sleep apnea. However, the benzodiazepine receptor agonists such as zaleplon, zolpidem, and eszopiclone, while lacking evidence in the pediatric population, may be worthwhile considerations as their varying half-lives allow for specificity in treating sleep-onset vs. sleep-maintenance problems. Caregivers should be warned about the potential for sleepwalking or other complex sleep-related behaviors with this class of medicines.

Avoid tricyclic antidepressants because of the potential for anticholinergic effects and cardiotoxicity. Atypical antipsychotics generally are not worth the risk of serious and rapid side effects associated with this class of medications, which include metabolic syndrome.

Dr. Rosenfeld is assistant professor of psychiatry at Vermont Center for Children, Youth & Families, at the University of Vermont Medical Center, and the University of Vermont, Burlington. He has received honorarium from Oakstone Publishing for contributing board review course content on human development.

References

1. International Classification of Sleep Disorders: Diagnostic & Coding Manual. 2nd edition. (Westchester: American Academy of Sleep Medicine, 2005).

2. Child Adolesc Psychiatr Clin N Am. 2009 Oct;18(4):979-1000

3. J Child Psychol Psychiatry. 2017, Oct 20. doi: 10.1111/jcpp.12834.

4. Child Adolesc Psychiatric Clin N Am. 2009, Oct;18(4):1001-16.

The first integrated continuous glucose monitoring system suitable for patients as young as 2 years has received market clearance from the Food and Drug Administration.

The Dexcom G6 is about 28% smaller than its predecessor, the G5, can be worn for up to 10 days – 43% longer than the G5 – and doesn’t require any finger-stick calibrations or treatment decisions. It’s the first FDA-approved integrated continuous glucose monitoring (iCGM) system that can link electronically to other compatible devices, including automated insulin dosing systems, insulin pumps, blood glucose meters, and other electronic devices used for diabetes management, the FDA said in a press statement. Its revamped sensor doesn’t interact with acetaminophen – another distinct advantage over the G5.

Dexcom

msullivan@MDedge.com

The first integrated continuous glucose monitoring system suitable for patients as young as 2 years has received market clearance from the Food and Drug Administration.

The Dexcom G6 is about 28% smaller than its predecessor, the G5, can be worn for up to 10 days – 43% longer than the G5 – and doesn’t require any finger-stick calibrations or treatment decisions. It’s the first FDA-approved integrated continuous glucose monitoring (iCGM) system that can link electronically to other compatible devices, including automated insulin dosing systems, insulin pumps, blood glucose meters, and other electronic devices used for diabetes management, the FDA said in a press statement. Its revamped sensor doesn’t interact with acetaminophen – another distinct advantage over the G5.

Dexcom

msullivan@MDedge.com

The first integrated continuous glucose monitoring system suitable for patients as young as 2 years has received market clearance from the Food and Drug Administration.

The Dexcom G6 is about 28% smaller than its predecessor, the G5, can be worn for up to 10 days – 43% longer than the G5 – and doesn’t require any finger-stick calibrations or treatment decisions. It’s the first FDA-approved integrated continuous glucose monitoring (iCGM) system that can link electronically to other compatible devices, including automated insulin dosing systems, insulin pumps, blood glucose meters, and other electronic devices used for diabetes management, the FDA said in a press statement. Its revamped sensor doesn’t interact with acetaminophen – another distinct advantage over the G5.

Dexcom

msullivan@MDedge.com

ABSTRACT

This article aims to provide the information necessary to prevent femoral trial head loss and to offer information regarding retrieval of the trial head if it is lost within the surgical field. These techniques can be used to help guide practice in the future. A review of the literature was conducted using a computerized search of PubMed in regard to this issue to investigate how such an occurrence can be prevented and what steps can be taken if preventative measures fail.

Continue to: Total hip arthroplasty...

Total hip arthroplasty (THA) is becoming an increasingly common procedure. Although this procedure is frequently performed, intraoperative complications still arise; therefore, methods of preventing and ameliorating these complications must be devised. One such complication is the loss of the femoral trial head component within the patient.

Loss of the trial head has been documented in THA cases that have used a number of different surgical approaches.¹ Although it is uncommon to lose the trial within the pelvis, it is not an entirely unlikely phenomenon. The possibility of such an event makes prevention important, especially given the associated morbidity that loss of the component could cause. Fortunately, there are preventative measures that can be taken to minimize the probability of losing the femoral trial head, in addition to techniques that can be utilized if prevention fails.

SURGICAL TECHNIQUE

PREVENTION

Firstly, it is important to avoid the use of worn-out femoral trial components. It is thought that the incidence of femoral trial head loss is increased when the trunnion is older and has been used repeatedly.^2,3 Therefore, it is advised that the use of worn femoral trial stems and other older trial components be avoided.

When the femoral trial head disengages anteriorly, it has the potential to enter the pelvis/retroperitoneal space.^2,4 The femoral trial head may move more freely in the absence of resistance offered by the anterior capsule.⁴ Therefore, when extensive anterior capsular dissection has taken place, such as during extensive capsulectomy, caution should be exercised when manipulating the hip. This emphasizes the necessity to closely monitor the head during any manipulation, particularly in the presence of significant anterior capsule disruption.

Modular hip arthroplasty prosthetics allow for various intraoperative changes to be made to the femoral component, providing greater specificity to the prosthesis.⁵ However, the modularity of the femoral component has been described as a factor contributing to loss of the femoral trial head.⁴ This also has been discussed with respect to the implantable prosthetic femoral head itself because of disengagement from the femoral stem during reduction and dislocation.⁴

Continue to: Case reports have cited...

Case reports have cited the tension of the soft tissues as a definitive factor in trial head loss.^1,4,6 These reports discuss the notion that more tension within the soft tissue can increase the likelihood that the trial head will dislodge during reduction or dislocation. Surgeons should therefore consider taking special care when manipulating the trial joint when the soft tissues are particularly tight and offer significant resistance. It has been suggested that the incision be packed with gauze during reductions when the soft tissue is under significant tension in order to keep the femoral trial head from entering the pelvis.⁶

A simple technique that can be utilized in the prevention of femoral trial head loss is the placement of a suture through the apical hole in the trial head to aid in the retrieval of the implant if it is lost.¹ Madsen and colleagues¹ suggest the placement of a No.1 (or thicker) suture through this hole. Although this takes some time to perform, it could prove useful in the prevention of complicated implant loss.

Lastly, and perhaps most importantly, it is essential that there is communication and understanding between the surgeon and any assistants. This has been noted to be particularly important during posterior or lateral surgical approaches when the trial head can be lost during attempts at reduction with traction and internal rotation.² Given the possibility of losing the trial head during this reduction maneuver, communication between the team during the reduction is instrumental.

RETRIEVAL

If the femoral trial head dissociates from the trunnion of the femoral trial manipulation, there are some techniques that can be used to aid in retrieval. It has been described that when the trial head is lost within the surgical wound, it can travel underneath the rectus femoris muscle and cross the pelvic brim, subsequently entering the pelvis along the psoas tendon, as the psoas bursa offers little resistance to the smooth femoral trial head.¹ The trial head has been found to follow this path along the psoas tendon until it is located in the posterior pelvis within the retroperitoneal space.^1,7 What follows is a compilation of techniques for approaching loss of the femoral trial head when it occurs.

The femoral trial head is round and smooth, which complicates its retrieval. If the surgeon tries to simply grab the component with fingers, it may slip away into the pelvis. When trialing the hip to assess for anterior stability, if the femoral trial head is lost, the leg should not be moved.⁷ At this point, a manual attempt to recover the trial head before it moves into the pelvis along the psoas tendon should be made.⁷ It is possible that the femoral trial head may spin when trying to retrieve it, however this should still be attempted before a formal additional surgical approach is employed.⁷ It has also been noted that one can manually simultaneously press down on the hypogastrium toward the iliac fossa in order to inhibit the movement of the disarticulated trial head from advancing proximally.³ After performing this maneuver, the femoral trial head can be retrieved through the inguinal canal.³

Continue to: Additional surgical approaches...

Additional surgical approaches can also be utilized for retrieval of the femoral trial head if other measures fail. Callaghan and colleagues⁷ describe a separate surgical approach that can be used to retrieve the trial component after losing the trial head during a posterolateral approach for THA. This technique is commenced by making a 6-cm to 7-cm incision along the iliac crest to the anteromedial aspect of the anterior superior iliac spine.⁷ The interval between the iliacus and the inner table of the iliac wing is developed, and an attempt is made to locate the femoral trial head and guide it distally along the pelvis toward the hip. Fingers or napkin forceps can be used to accomplish this advancement of the trial head distally toward the hip, and once reaching surgical site, the trial can then be retrieved.⁷ Further extension of the incision can be made distally if this limited approach is unsuccessful.⁷ In the event the femoral trial head is still unable to be retrieved, the authors suggest considering a dedicated retroperitoneal approach for trial retrieval after the arthroplasty procedure has been completed.⁷

Another method for retrieval of the femoral trial head has been described specifically in the setting of a direct lateral approach.⁸ Kalra and colleagues⁸ describe a case in which the trial femoral head dislocated anteriorly, and although it was unable to be visualized, the component was able to be palpated posterior to the superior pubic ramus. With the trial head still disassociated within the pelvis, the final implants were implanted. Although the trial was unable to be viewed, using the same incision for the direct lateral approach, the trial femoral head was guided posteriorly toward the sciatic notch. A posterior approach to the hip was then performed using the same initial direct lateral incision used. Subsequent exposure and release of the external rotators and posterior capsule was performed, as was release of the insertion of the gluteus maximus in order to facilitate better visualization and to prevent excessive tension on the sciatic nerve. Blunt finger dissection of the soft tissues was then performed, and the trial head was retrieved from the sciatic notch with a Kocher clamp.⁸

Madsen and colleagues¹ highlight two different cases in which the trial head was lost into the pelvis when using an anterolateral (modified Watson-Jones) approach to the hip to perform THA. As previously alluded to, the trial heads traveled along the patients’ psoas muscle and stopped directly anterior to their sacroiliac joint. In both cases, the trial head was retrieved using a large Satinsky aortic clamp, which enabled the surgeons to drag the trial head to the pelvic brim where it could be removed with a hemostat.¹

Multiple authors have discussed the decision to leave the component within the pelvis if the femoral trial head cannot be retrieved.^2,4,7 Batouk and colleagues⁴ noted that in a case of loss of the femoral trial head, the component would be unlikely to disrupt any of the structures within the pelvis, and in the absence of compression of any vital structures, leaving the implant in the patient could be considered. Although the short-term follow-up of 3 months noted in this particular case did not yield any obvious detriment to the patient in regard to symptomatology, the authors note that the long-term effects of such a practice is unclear.⁴ In another case, in which the decision was made to leave the femoral trial head, the patient at postoperative week 6 began to hear clicking in the hip with an associated loss of range of motion.⁷ This subsequently prompted removal of the trial component.

DISCUSSION

Although not a particularly common complication, loss of the femoral trial head can occur; therefore, a plan of action should be in place to prevent its loss or to retrieve it if prevention is ineffective. Given the modularity of various arthroplasty systems in regard to the different trial components or even the final implantable prosthetic devices, component loss is a possibility. An understanding of this complication and the appropriate steps to approaching it could aid in preventing patient morbidity. Because of this, it is imperative that surgeons who perform THA be aware of the potential complications and the measures that can be taken to address them.

Continue to: CONCLUSION

 

 

CONCLUSION

The femoral trial head often can be quickly and easily recovered; however, trial component recovery can sometimes be more complicated. Loss of the trial femoral head could potentially occur during dislocation, reduction, or any of the trial positions. An example of a more complicated recovery is when the femoral trial head is lost into the retroperitoneal space, which could occur when trialing the hip in extension to assess the anterior stability of the hip. Loss of the femoral trial head is an avoidable occurrence, and it has the potential to cause a number of complications as well as the need for additional incisions/surgery to retrieve the femoral trial head. The subsequent issues that could arise after loss occurs can not only lead to extensive surgical complications, but can also foster patient dissatisfaction regarding surgical outcomes. Therefore, consistent attempts to utilize preventative techniques are essential. As discussed, simple measures such as placement of a suture through the apical hole of the trial component and adequate communication between those involved in reduction and trialing maneuvers, can serve to avert femoral trial head loss.

ABSTRACT

This article aims to provide the information necessary to prevent femoral trial head loss and to offer information regarding retrieval of the trial head if it is lost within the surgical field. These techniques can be used to help guide practice in the future. A review of the literature was conducted using a computerized search of PubMed in regard to this issue to investigate how such an occurrence can be prevented and what steps can be taken if preventative measures fail.

Continue to: Total hip arthroplasty...

Total hip arthroplasty (THA) is becoming an increasingly common procedure. Although this procedure is frequently performed, intraoperative complications still arise; therefore, methods of preventing and ameliorating these complications must be devised. One such complication is the loss of the femoral trial head component within the patient.

Loss of the trial head has been documented in THA cases that have used a number of different surgical approaches.¹ Although it is uncommon to lose the trial within the pelvis, it is not an entirely unlikely phenomenon. The possibility of such an event makes prevention important, especially given the associated morbidity that loss of the component could cause. Fortunately, there are preventative measures that can be taken to minimize the probability of losing the femoral trial head, in addition to techniques that can be utilized if prevention fails.

SURGICAL TECHNIQUE

PREVENTION

Firstly, it is important to avoid the use of worn-out femoral trial components. It is thought that the incidence of femoral trial head loss is increased when the trunnion is older and has been used repeatedly.^2,3 Therefore, it is advised that the use of worn femoral trial stems and other older trial components be avoided.

When the femoral trial head disengages anteriorly, it has the potential to enter the pelvis/retroperitoneal space.^2,4 The femoral trial head may move more freely in the absence of resistance offered by the anterior capsule.⁴ Therefore, when extensive anterior capsular dissection has taken place, such as during extensive capsulectomy, caution should be exercised when manipulating the hip. This emphasizes the necessity to closely monitor the head during any manipulation, particularly in the presence of significant anterior capsule disruption.

Modular hip arthroplasty prosthetics allow for various intraoperative changes to be made to the femoral component, providing greater specificity to the prosthesis.⁵ However, the modularity of the femoral component has been described as a factor contributing to loss of the femoral trial head.⁴ This also has been discussed with respect to the implantable prosthetic femoral head itself because of disengagement from the femoral stem during reduction and dislocation.⁴

Continue to: Case reports have cited...

Case reports have cited the tension of the soft tissues as a definitive factor in trial head loss.^1,4,6 These reports discuss the notion that more tension within the soft tissue can increase the likelihood that the trial head will dislodge during reduction or dislocation. Surgeons should therefore consider taking special care when manipulating the trial joint when the soft tissues are particularly tight and offer significant resistance. It has been suggested that the incision be packed with gauze during reductions when the soft tissue is under significant tension in order to keep the femoral trial head from entering the pelvis.⁶

A simple technique that can be utilized in the prevention of femoral trial head loss is the placement of a suture through the apical hole in the trial head to aid in the retrieval of the implant if it is lost.¹ Madsen and colleagues¹ suggest the placement of a No.1 (or thicker) suture through this hole. Although this takes some time to perform, it could prove useful in the prevention of complicated implant loss.

Lastly, and perhaps most importantly, it is essential that there is communication and understanding between the surgeon and any assistants. This has been noted to be particularly important during posterior or lateral surgical approaches when the trial head can be lost during attempts at reduction with traction and internal rotation.² Given the possibility of losing the trial head during this reduction maneuver, communication between the team during the reduction is instrumental.

RETRIEVAL

If the femoral trial head dissociates from the trunnion of the femoral trial manipulation, there are some techniques that can be used to aid in retrieval. It has been described that when the trial head is lost within the surgical wound, it can travel underneath the rectus femoris muscle and cross the pelvic brim, subsequently entering the pelvis along the psoas tendon, as the psoas bursa offers little resistance to the smooth femoral trial head.¹ The trial head has been found to follow this path along the psoas tendon until it is located in the posterior pelvis within the retroperitoneal space.^1,7 What follows is a compilation of techniques for approaching loss of the femoral trial head when it occurs.

The femoral trial head is round and smooth, which complicates its retrieval. If the surgeon tries to simply grab the component with fingers, it may slip away into the pelvis. When trialing the hip to assess for anterior stability, if the femoral trial head is lost, the leg should not be moved.⁷ At this point, a manual attempt to recover the trial head before it moves into the pelvis along the psoas tendon should be made.⁷ It is possible that the femoral trial head may spin when trying to retrieve it, however this should still be attempted before a formal additional surgical approach is employed.⁷ It has also been noted that one can manually simultaneously press down on the hypogastrium toward the iliac fossa in order to inhibit the movement of the disarticulated trial head from advancing proximally.³ After performing this maneuver, the femoral trial head can be retrieved through the inguinal canal.³

Continue to: Additional surgical approaches...

Additional surgical approaches can also be utilized for retrieval of the femoral trial head if other measures fail. Callaghan and colleagues⁷ describe a separate surgical approach that can be used to retrieve the trial component after losing the trial head during a posterolateral approach for THA. This technique is commenced by making a 6-cm to 7-cm incision along the iliac crest to the anteromedial aspect of the anterior superior iliac spine.⁷ The interval between the iliacus and the inner table of the iliac wing is developed, and an attempt is made to locate the femoral trial head and guide it distally along the pelvis toward the hip. Fingers or napkin forceps can be used to accomplish this advancement of the trial head distally toward the hip, and once reaching surgical site, the trial can then be retrieved.⁷ Further extension of the incision can be made distally if this limited approach is unsuccessful.⁷ In the event the femoral trial head is still unable to be retrieved, the authors suggest considering a dedicated retroperitoneal approach for trial retrieval after the arthroplasty procedure has been completed.⁷

Another method for retrieval of the femoral trial head has been described specifically in the setting of a direct lateral approach.⁸ Kalra and colleagues⁸ describe a case in which the trial femoral head dislocated anteriorly, and although it was unable to be visualized, the component was able to be palpated posterior to the superior pubic ramus. With the trial head still disassociated within the pelvis, the final implants were implanted. Although the trial was unable to be viewed, using the same incision for the direct lateral approach, the trial femoral head was guided posteriorly toward the sciatic notch. A posterior approach to the hip was then performed using the same initial direct lateral incision used. Subsequent exposure and release of the external rotators and posterior capsule was performed, as was release of the insertion of the gluteus maximus in order to facilitate better visualization and to prevent excessive tension on the sciatic nerve. Blunt finger dissection of the soft tissues was then performed, and the trial head was retrieved from the sciatic notch with a Kocher clamp.⁸

Madsen and colleagues¹ highlight two different cases in which the trial head was lost into the pelvis when using an anterolateral (modified Watson-Jones) approach to the hip to perform THA. As previously alluded to, the trial heads traveled along the patients’ psoas muscle and stopped directly anterior to their sacroiliac joint. In both cases, the trial head was retrieved using a large Satinsky aortic clamp, which enabled the surgeons to drag the trial head to the pelvic brim where it could be removed with a hemostat.¹

Multiple authors have discussed the decision to leave the component within the pelvis if the femoral trial head cannot be retrieved.^2,4,7 Batouk and colleagues⁴ noted that in a case of loss of the femoral trial head, the component would be unlikely to disrupt any of the structures within the pelvis, and in the absence of compression of any vital structures, leaving the implant in the patient could be considered. Although the short-term follow-up of 3 months noted in this particular case did not yield any obvious detriment to the patient in regard to symptomatology, the authors note that the long-term effects of such a practice is unclear.⁴ In another case, in which the decision was made to leave the femoral trial head, the patient at postoperative week 6 began to hear clicking in the hip with an associated loss of range of motion.⁷ This subsequently prompted removal of the trial component.

DISCUSSION

Although not a particularly common complication, loss of the femoral trial head can occur; therefore, a plan of action should be in place to prevent its loss or to retrieve it if prevention is ineffective. Given the modularity of various arthroplasty systems in regard to the different trial components or even the final implantable prosthetic devices, component loss is a possibility. An understanding of this complication and the appropriate steps to approaching it could aid in preventing patient morbidity. Because of this, it is imperative that surgeons who perform THA be aware of the potential complications and the measures that can be taken to address them.

Continue to: CONCLUSION

 

 

CONCLUSION

The femoral trial head often can be quickly and easily recovered; however, trial component recovery can sometimes be more complicated. Loss of the trial femoral head could potentially occur during dislocation, reduction, or any of the trial positions. An example of a more complicated recovery is when the femoral trial head is lost into the retroperitoneal space, which could occur when trialing the hip in extension to assess the anterior stability of the hip. Loss of the femoral trial head is an avoidable occurrence, and it has the potential to cause a number of complications as well as the need for additional incisions/surgery to retrieve the femoral trial head. The subsequent issues that could arise after loss occurs can not only lead to extensive surgical complications, but can also foster patient dissatisfaction regarding surgical outcomes. Therefore, consistent attempts to utilize preventative techniques are essential. As discussed, simple measures such as placement of a suture through the apical hole of the trial component and adequate communication between those involved in reduction and trialing maneuvers, can serve to avert femoral trial head loss.

ABSTRACT

This article aims to provide the information necessary to prevent femoral trial head loss and to offer information regarding retrieval of the trial head if it is lost within the surgical field. These techniques can be used to help guide practice in the future. A review of the literature was conducted using a computerized search of PubMed in regard to this issue to investigate how such an occurrence can be prevented and what steps can be taken if preventative measures fail.

Continue to: Total hip arthroplasty...

Total hip arthroplasty (THA) is becoming an increasingly common procedure. Although this procedure is frequently performed, intraoperative complications still arise; therefore, methods of preventing and ameliorating these complications must be devised. One such complication is the loss of the femoral trial head component within the patient.

Loss of the trial head has been documented in THA cases that have used a number of different surgical approaches.¹ Although it is uncommon to lose the trial within the pelvis, it is not an entirely unlikely phenomenon. The possibility of such an event makes prevention important, especially given the associated morbidity that loss of the component could cause. Fortunately, there are preventative measures that can be taken to minimize the probability of losing the femoral trial head, in addition to techniques that can be utilized if prevention fails.

SURGICAL TECHNIQUE

PREVENTION

Firstly, it is important to avoid the use of worn-out femoral trial components. It is thought that the incidence of femoral trial head loss is increased when the trunnion is older and has been used repeatedly.^2,3 Therefore, it is advised that the use of worn femoral trial stems and other older trial components be avoided.

When the femoral trial head disengages anteriorly, it has the potential to enter the pelvis/retroperitoneal space.^2,4 The femoral trial head may move more freely in the absence of resistance offered by the anterior capsule.⁴ Therefore, when extensive anterior capsular dissection has taken place, such as during extensive capsulectomy, caution should be exercised when manipulating the hip. This emphasizes the necessity to closely monitor the head during any manipulation, particularly in the presence of significant anterior capsule disruption.

Modular hip arthroplasty prosthetics allow for various intraoperative changes to be made to the femoral component, providing greater specificity to the prosthesis.⁵ However, the modularity of the femoral component has been described as a factor contributing to loss of the femoral trial head.⁴ This also has been discussed with respect to the implantable prosthetic femoral head itself because of disengagement from the femoral stem during reduction and dislocation.⁴

Continue to: Case reports have cited...

Case reports have cited the tension of the soft tissues as a definitive factor in trial head loss.^1,4,6 These reports discuss the notion that more tension within the soft tissue can increase the likelihood that the trial head will dislodge during reduction or dislocation. Surgeons should therefore consider taking special care when manipulating the trial joint when the soft tissues are particularly tight and offer significant resistance. It has been suggested that the incision be packed with gauze during reductions when the soft tissue is under significant tension in order to keep the femoral trial head from entering the pelvis.⁶

A simple technique that can be utilized in the prevention of femoral trial head loss is the placement of a suture through the apical hole in the trial head to aid in the retrieval of the implant if it is lost.¹ Madsen and colleagues¹ suggest the placement of a No.1 (or thicker) suture through this hole. Although this takes some time to perform, it could prove useful in the prevention of complicated implant loss.

Lastly, and perhaps most importantly, it is essential that there is communication and understanding between the surgeon and any assistants. This has been noted to be particularly important during posterior or lateral surgical approaches when the trial head can be lost during attempts at reduction with traction and internal rotation.² Given the possibility of losing the trial head during this reduction maneuver, communication between the team during the reduction is instrumental.

RETRIEVAL

If the femoral trial head dissociates from the trunnion of the femoral trial manipulation, there are some techniques that can be used to aid in retrieval. It has been described that when the trial head is lost within the surgical wound, it can travel underneath the rectus femoris muscle and cross the pelvic brim, subsequently entering the pelvis along the psoas tendon, as the psoas bursa offers little resistance to the smooth femoral trial head.¹ The trial head has been found to follow this path along the psoas tendon until it is located in the posterior pelvis within the retroperitoneal space.^1,7 What follows is a compilation of techniques for approaching loss of the femoral trial head when it occurs.

The femoral trial head is round and smooth, which complicates its retrieval. If the surgeon tries to simply grab the component with fingers, it may slip away into the pelvis. When trialing the hip to assess for anterior stability, if the femoral trial head is lost, the leg should not be moved.⁷ At this point, a manual attempt to recover the trial head before it moves into the pelvis along the psoas tendon should be made.⁷ It is possible that the femoral trial head may spin when trying to retrieve it, however this should still be attempted before a formal additional surgical approach is employed.⁷ It has also been noted that one can manually simultaneously press down on the hypogastrium toward the iliac fossa in order to inhibit the movement of the disarticulated trial head from advancing proximally.³ After performing this maneuver, the femoral trial head can be retrieved through the inguinal canal.³

Continue to: Additional surgical approaches...

Additional surgical approaches can also be utilized for retrieval of the femoral trial head if other measures fail. Callaghan and colleagues⁷ describe a separate surgical approach that can be used to retrieve the trial component after losing the trial head during a posterolateral approach for THA. This technique is commenced by making a 6-cm to 7-cm incision along the iliac crest to the anteromedial aspect of the anterior superior iliac spine.⁷ The interval between the iliacus and the inner table of the iliac wing is developed, and an attempt is made to locate the femoral trial head and guide it distally along the pelvis toward the hip. Fingers or napkin forceps can be used to accomplish this advancement of the trial head distally toward the hip, and once reaching surgical site, the trial can then be retrieved.⁷ Further extension of the incision can be made distally if this limited approach is unsuccessful.⁷ In the event the femoral trial head is still unable to be retrieved, the authors suggest considering a dedicated retroperitoneal approach for trial retrieval after the arthroplasty procedure has been completed.⁷

Another method for retrieval of the femoral trial head has been described specifically in the setting of a direct lateral approach.⁸ Kalra and colleagues⁸ describe a case in which the trial femoral head dislocated anteriorly, and although it was unable to be visualized, the component was able to be palpated posterior to the superior pubic ramus. With the trial head still disassociated within the pelvis, the final implants were implanted. Although the trial was unable to be viewed, using the same incision for the direct lateral approach, the trial femoral head was guided posteriorly toward the sciatic notch. A posterior approach to the hip was then performed using the same initial direct lateral incision used. Subsequent exposure and release of the external rotators and posterior capsule was performed, as was release of the insertion of the gluteus maximus in order to facilitate better visualization and to prevent excessive tension on the sciatic nerve. Blunt finger dissection of the soft tissues was then performed, and the trial head was retrieved from the sciatic notch with a Kocher clamp.⁸

Madsen and colleagues¹ highlight two different cases in which the trial head was lost into the pelvis when using an anterolateral (modified Watson-Jones) approach to the hip to perform THA. As previously alluded to, the trial heads traveled along the patients’ psoas muscle and stopped directly anterior to their sacroiliac joint. In both cases, the trial head was retrieved using a large Satinsky aortic clamp, which enabled the surgeons to drag the trial head to the pelvic brim where it could be removed with a hemostat.¹

Multiple authors have discussed the decision to leave the component within the pelvis if the femoral trial head cannot be retrieved.^2,4,7 Batouk and colleagues⁴ noted that in a case of loss of the femoral trial head, the component would be unlikely to disrupt any of the structures within the pelvis, and in the absence of compression of any vital structures, leaving the implant in the patient could be considered. Although the short-term follow-up of 3 months noted in this particular case did not yield any obvious detriment to the patient in regard to symptomatology, the authors note that the long-term effects of such a practice is unclear.⁴ In another case, in which the decision was made to leave the femoral trial head, the patient at postoperative week 6 began to hear clicking in the hip with an associated loss of range of motion.⁷ This subsequently prompted removal of the trial component.

DISCUSSION

Although not a particularly common complication, loss of the femoral trial head can occur; therefore, a plan of action should be in place to prevent its loss or to retrieve it if prevention is ineffective. Given the modularity of various arthroplasty systems in regard to the different trial components or even the final implantable prosthetic devices, component loss is a possibility. An understanding of this complication and the appropriate steps to approaching it could aid in preventing patient morbidity. Because of this, it is imperative that surgeons who perform THA be aware of the potential complications and the measures that can be taken to address them.

Continue to: CONCLUSION

 

 

CONCLUSION

The femoral trial head often can be quickly and easily recovered; however, trial component recovery can sometimes be more complicated. Loss of the trial femoral head could potentially occur during dislocation, reduction, or any of the trial positions. An example of a more complicated recovery is when the femoral trial head is lost into the retroperitoneal space, which could occur when trialing the hip in extension to assess the anterior stability of the hip. Loss of the femoral trial head is an avoidable occurrence, and it has the potential to cause a number of complications as well as the need for additional incisions/surgery to retrieve the femoral trial head. The subsequent issues that could arise after loss occurs can not only lead to extensive surgical complications, but can also foster patient dissatisfaction regarding surgical outcomes. Therefore, consistent attempts to utilize preventative techniques are essential. As discussed, simple measures such as placement of a suture through the apical hole of the trial component and adequate communication between those involved in reduction and trialing maneuvers, can serve to avert femoral trial head loss.