Osteoarthritis (OA) of the knee usually presents bilaterally. However, not every patient with severe bilateral knee OA require bilateral total knee arthroplasty (TKA). A prospective study was conducted to determine predictive factors for contralateral TKA in patients with severe bilateral knee OA who had to undergo unilateral TKA. Perioperative data was collected from 209 consecutive patients of a single surgeon who had severe bilateral knees OAat presentation. All patients underwent unilateral TKA on the more symptomatic knee. Subsequently, patients were stratified according to their need for a contralateral TKA within the next 5 years. Regression analysis was used to compare patients who underwent contralateral knee surgery within 5 years (n = 115) against patients who did not (n = 94) to create a predictive model. Body mass index (BMI), degree of varus angulation, and Oxford knee scores were reported to be significant predictive factors. The generated decision tree model stratified patients according to their BMI and Oxford scores into 4 subcategories, the highest with over 90% odds of contralateral surgery and the lowest with less than 40% odds of contralateral surgery. Based on this data, it can be concluded that BMI, degree of varus angulation, and pre-operative Oxford knee scores may be useful for predicting the need for contralateral TKA in patients with severe bilateral knees OA undergoing unilateral TKA. These factors could be used for counselling these patients on their requirement for second TKA.

Source: J Knee Surg. 2020 Oct;33(10):1029-1033.