Predictors of subsequent contralateral total knee arthroplasty in moderate-to-severe bilateral medial knee osteoarthritis

Abstract

Purpose

In patients with moderate-to-severe bilateral medial knee osteoarthritis, it is difficult to determine the necessity of the subsequent contralateral total knee arthroplasty (TKA) after performing the first procedure. This study aimed to compare patient characteristics and clinical outcomes between patients who underwent staged bilateral TKA (group B) and those who underwent unilateral TKA (group U) to identify predictors of contralateral TKA requirement.

Methods

Among 153 patients with bilateral medial knee osteoarthritis of Kellgren-Lawrence grade 3 or 4, 43 and 110 patients underwent unilateral and bilateral TKA, respectively. Clinical evaluations using the patient-reported outcome measure (the Japanese Knee Osteoarthritis Measure [JKOM]), the Knee Society Score (KSS), and the timed “Up and Go” test (TUG) were performed preoperatively, at 12 months, and once every year up to 5 years after the unilateral and the contralateral TKA in groups U and B, respectively. Receiver Operating Characteristic (ROC) analysis was used to determine the cut-off value for preoperative JKOM score that indicates the contralateral TKA.

Results

There were no significant differences in patient characteristics between groups B and U. The preoperative JKOM scores were significantly worse in group B. Postoperative improvements in JKOM, KSS, and TUG were statistically significant in both groups; however, there were no significant differences in post-procedure scores between the two groups. ROC analysis showed that the optimal cut-off value of the preoperative JKOM score was 41.5 points.

Conclusion

A preoperative JKOM score of ≥41.5 is a possible predictor of the contralateral TKA in patients with moderate-to-severe bilateral medial knee osteoarthritis.