Bariatric Orthopaedics: Impact of Obesity on Total Knee Replacement

Abstract Introduction: Total knee replacement is a reliable operation for reducing pain and improving function in severe osteoarthritis of the knee. As incidence of obesity is increasing worldwide, there is a debate about the role of Body Mass Index (BMI) in selection of patients requiring total knee replacement. The aim of the study was to evaluate the impact of body mass index on total knee replacement in terms of post-operative improvement in knee range of motion, patient satisfaction and complications.Material and methods: Out of 175 patients who suffered from advance knee osteoarthritis and were candidates for primary total knee replacement from January 2016 to March 2018, 155 patients fit the inclusion criteria. Group 1 included 66 patients who were overweight and class 1 obese while group 2 included 89 patients who were class 2 and 3 obese according to WHO Body Mass Index classification. All patients underwent total knee replacement according to the hospital guidelines. Pre and post-operative range of motion, patient satisfaction and complications were assessed and documented. Results: There was no statistically significant difference in improvements in post-operative knee range of motion between the two groups up to 2 years of follow up. [Mann-Whitney U test p= 0.069]. Similarly, Mann-Whitney U test showed that there is no significant difference between patient satisfaction levels (SF-12 scores) of the two groups (p= 0.09). Conclusion: There is no significant impact of obesity on outcomes after total knee replacement and BMI should not be used as a factor in selecting patients who qualify for total knee replacement.Level of Evidence: Level III