The effect of leg length discrepancy on clinical outcome after TKA and identification of possible risk factors.

Abstract

This study was investigated on the leg length discrepancy (LLD) after computer-assisted total knee arthroplasty (TKA), and its effects on the post-operative function and patient satisfaction. It is hypothesized that LLD after computer-assisted TKA would affect the clinical outcomes for knee scores.

A total of 148 cases were analysed retrospectively with a minimum of 2 years of follow-up. Eighty-one knees involved a < 15-mm LLD, and 67 knees involved more than a 15-mm LLD. The radiographic outcomes, clinical outcomes, patients' satisfaction, and perception of LLD were also evaluated.

There was a significant difference in the Knee Society function score and the score for the difficulty with ascending the stairs in the Western Ontario and McMaster Universities score between the groups. There was a statistically significant difference between the two groups in the results of their perception questionnaires, but no difference in the results of their satisfaction questionnaires. The odds ratio for the risk of post-operative LLD increased with the increased pre-operative LLD and the unilateral TKA.

In conclusion, the functional outcomes of more than 15-mm post-operative LLD after computer-assisted TKA were lower than those of the < 15-mm LLD. Thus, the reduced post-operative LLD should be considered to improve the functional outcomes of primary TKA. A careful treatment plan for degenerative arthritis should be considered and discussed with patients, especially in unilateral TKAs.