Total Knee Arthroplasty in Morbis Obese Patients, Outcome, Complications and Surgical Tips to Improve Results

Introduction: Obesity is a significant risk factor for developing knee osteoarthritis and increased need for knee arthroplasty procedures. Obese patients have inferior outcome following total knee arthroplasty (TKR) compared to non-obese patients, and are more likely to suffer from surgical complications. The goal of the present study was to evaluate the outcome of TKR and rate of complications in morbid obesity (BMI >40) compared to regular obese patients (40>BMI >30).

Materials and Methods: A study base on our prospective data base was conducted, we compared the surgical outcome based on the Knee society score (KSS) and rate of complications (surgical site infection, skin necrosis , thromboembolic events, peripheral nerve injuries , late infections, knee manipulations, implant loosening and revision for any reason) following TKR between obese patients 40>BMI >30 (Cohort A) and morbid obese BMI >40 (Cohort B).

Results: There were 131 patients in cohort A (mean BMI = 35.2) and 123 patients in cohort B (mean BMI = 46). The mean follow-up was 5.6 years. There were no significant differences regarding KSS between the cohorts, 85.7 and 85.3 in cohort A and cohort B, respectively (p=0.276) . The surgical incision was significantly longer in cohort B. In cohort B there was increased risk for surgical complications including: superficial and deep infections, skin necrosis, nerve injuries and thromboembolic events. Morbid obesity didn’t increase the risk for aseptic loosening.

Conclusions: Our data suggest that morbid obese patients may have the benefits of TKR as regular patients, however, they have increased risk for systemic and local surgical complications.