Does Metabolic Syndrome Impact the Risk of Reoperation, Revision, or Complication After Primary Total Knee Arthroplasty?

BACKGROUND: Metabolic syndrome (MetS) is an increasingly frequent condition characterized by insulin resistance, abdominal obesity, hypertension, and dyslipidemia. This study evaluated implant survivorship, complications, and clinical outcomes of primary TKAs performed in patients who have MetS. METHODS: Utilizing our institutional total joint registry, 2,063 primary TKAs were performed in patients with a diagnosis of MetS according to the World Health Organization criteria. MetS patients were matched 1:1 based on age, sex, and surgical year to those who did not have the condition. The World Health Organization's body mass index (BMI) classification was utilized to evaluate the effect of obesity within MetS patients. Kaplan-Meier methods were utilized to determine implant survivorship. Clinical outcomes were assessed with Knee Society scores. The mean follow-up was 5 years. RESULTS: MetS and non-MetS patients did not have significant differences in 5-year implant survivorship free from any reoperation (P = .7), any revision (P = .2), and reoperation for periprosthetic joint infection (PJI; P = .2). When stratifying, patients with MetS and BMI >40 had significantly decreased 5-year survivorship free from any revision (95 versus 98%, respectively; hazard ratio = 2.1, P = .005) and reoperation for PJI (97 versus 99%, respectively; hazard ratio = 2.2, P = .02). Both MetS and non-MetS groups experienced significant improvements in Knee Society Scores (77 versus 78, respectively; P < .001) that were not significantly different (P = .3). CONCLUSION: MetS did not significantly increase the risk of any reoperation after TKA; however, MetS patients with BMI >40 had a two-fold risk of any revision and reoperation for PJI. These results suggest that obesity is an important condition within MetS criteria and remains an independent risk factor. LEVEL OF EVIDENCE: Level 3, Case-control study.

A retrospective case series of prophylactic neurectomy during total knee arthroplasty.

INTRODUCTION: Total knee arthroplasty is a common operation performed to relieve pain and restore functional activity. While overall widely successful, a subset of patients has continued pain postoperatively with no identifiable cause. Neuroma formation has been identified as a possible contributor to this unexplained pain, often necessitating an additional procedure for neuroma removal. The purpose of our study was to evaluate if prophylactic neurectomy could reduce the occurrence of postoperative pain. METHODS: A total of 112 patients were compared, 44 control patients and 68 neurectomy patients. Demographic information, Numerical rating pain scale (NRS) and Knee Society Scores (KSS) were collected pre- and post-operatively. Patients were additional asked if they were overall satisfied with the operation. RESULTS: There were no differences between groups with respect to age (Median: 71 vs 69 years, p = 0.28), male sex (41% vs 44%, p = 0.85), or body mass index (Median: 32.2 vs 31.3, p = 0.80). When comparing the degree of change following surgery there were no statistically significant differences observed in NRS pain scores (Median change: -7 vs -6, p = 0.89) or KSS scores (Median change: +44 vs +40, p = 0.14). Similarly, there was no statistically significant difference in overall patient-reported satisfaction with the knee replacement (82.5% vs 86.6%, p = 0.59). CONCLUSION: We did not find a statistically significant difference in NRS, KSS, or overall patient satisfaction between the prophylactic neurectomy and control patient groups. Larger studies with evaluation of the nerve diameter will be needed to determine which patients are at risk for symptomatic neuroma development following total knee arthroplasty.