Summary

Single limb total knee arthroplasty does not affect contralateral limb alignment and pain.

Abstract

Purpose

This study aimed to determine the effect of excessive alignment correction and postoperative leg length discrepancy (LLD) in unilateral total knee arthroplasty (TKA) on the contralateral lower extremity alignment and knee condition.

Methods

:We retrospectively assessed 127 patients who underwent unilateral TKA. The patients were divided into preoperative hip-knee-ankle angle of operation side < 10˚ (Absolute non-excessive correction, N = 85) and ≥ 10˚ (Absolute excessive correction, N = 42) groups or preoperative HKA difference between operation and contralateral side < 5˚ (Relative non-excessive correction, N = 74) and ≥ 5˚ (Relative excessive correction, N = 53) groups or operation side > contralateral side (N = 103) and operation side ≤ contralateral side lower extremity length (N = 24) groups. Contralateral HKA (cHKA), contralateral joint line convergence angle (cJLCA), and contralateral knee pain Visual Analog Scale (VAS) between preoperative and 1 year after TKA were compared between groups, respectively.

Results

There was no significant difference in cHKA, cJLCA, and contralateral knee pain between before TKA and 1 year after TKA in all groups (P > 0.05). Although the mean pain VAS of contralateral knee of op side > contralateral side lower extremity length group worsened from 2.7 ± 2.2 preoperatively to 3.2 ± 2.4 postoperatively (P = 0.018), this did not meet the minimum clinically important difference (MCID) for pain VAS.

Conclusions

Excessive alignment correction and postoperative LLD in unilateral TKA might not change the contralateral lower extremity alignment and knee condition in the early postoperative period. The present cohort of patients will need to be followed up to determine whether their alignment and knee condition change.