Summary

Contrary to conventional knowledge, under-corrected surgery was not associated with inferior clinical outcomes. Over-correction should be avoided to ensure patient satisfaction.

Abstract

Background

Achieving the postoperative mechanical axis passing through 62.5% of the tibial plateau is considered a successful surgery. Despite precise preoperative planning and surgical techniques, some surgeries result in under-correction or over-correction. Few studies have investigated the relationship between clinical outcomes and unintentional under-correction or over-correction after open wedge high tibial osteotomy (OWHTO) using whole-leg standing radiographs.

Purpose

To investigate the relationship between postoperative alignment using whole-leg standing radiographs and clinical outcomes following OWHTO.

Methods

A total of 89 knees (72 patients) who underwent OWHTO between October 2013 and September 2018 were enrolled. Patients with postoperative weight-bearing line (WBL) ratios within 57?67% were classified as appropriate correction (group A, 20 cases), whereas ratios <57% and >67% were classified as under-correction (group U, 45 cases) and over-correction (group O, 24 cases), respectively. The patient-reported outcomes (PRO), including International Knee Documentation Committee (IKDC) subjective score, Kujala score, and Knee Injury and Osteoarthritis Outcome Score (KOOS) were investigated. The correlation between postoperative WBL and PRO was analyzed. PRO were compared between 3 groups.

Results

Regarding the correlation between postoperative WBL ratio and PRO, the greater postoperative WBL ratio was significantly correlated with a poor IKDC subjective score (P = 0.002), Kujala score (P = 0.009), and KOOS. Group O showed inferior postoperative PRO compared to group A or group U, whereas group U showed similar results compared to group A. (mean IKDC subjective score of group U, A, and O; 62.0, 61.2, 47.6; P = 0.004)

Conclusion

Over-corrected surgery correlated with inferior PRO after OWHTO; therefore, over-corrected alignment should be avoided for patient satisfaction. The under-corrected alignment showed clinical results similar to those of the appropriate correction.