T-F subluxation was well corrected after CW and OWHTO and degree of T-F subluxation correction was not different between two groups
Tibiofemoral (T-F) subluxation is a common finding in the medial compartment osteoarthritis of knee with varus deformity. But the degree of T-F subluxation correction after high tibial osteotomy (HTO) and variables related to the T-F subluxation were not understood well. The purposes of this study were 1) to compare correction of T-F subluxation after lateral closing wedge (CW) and medial opening wedge (OW) HTO and 2) to find the variables related to the T-F subluxation.
In this prospective randomized comparative study, 30 unilateral CWHTO’s and 30 unilateral OWHTO’s for medial compartmental osteoarthritis with 1 year follow up were analyzed. The hip-knee-ankle (H-K-A) angle, T-F subluxation, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), Hospital for Special Surgery (HSS) score, Visual Analogue Scale (VAS) were measured preoperatively and 1 year postoperatively. Pearson’s correlation analysis was conducted to find the variables related to preoperative and postoperative 1-year (residual) T-F subluxation.
The mean T-F subluxation changed from 3.9±2.3mm to 1.4±1.4mm (p < 0.01) after CWHTO, while it changed from 4.3±1.8mm to 1.4±1.5mm (p<0.01) after OWHTO. The mean T-F subluxation correction was not different between two groups (2.5±2.0mm in CWHTO versus 2.9±1.9mm in OWHTO, p=0.36). Correlated variables for preoperative T-F subluxation were preoperative H-K-A angle (r=0.43, p=0.01), KSKS (r=-0.42, p<0.05), VAS (r=0.38, p<0.05) in CWHTO group while preoperative H-K-A angle (r=0.47, p<0.01), VAS (r=0.52, p<0.05) in OWHTO group. Residual T-F subluxation was significantly correlated with preoperative T-F subluxation in both groups (r=0.52, p<0.01 in CWHTO versus r=0.37, p<0.05 in OWHTO) but it was not correlated with any of postoperative clinical scores in both groups (p>0.05). KSS, HSS, VAS score improved significantly in both groups (p<0.01).
T-F subluxation was well corrected after CW and OWHTO and degree of T-F subluxation correction was not different between two groups. Although, preoperative T-F subluxation was one of possible reason for poor clinical scores, residual T-F subluxation was negligible and did not affect any of the postoperative clinical scores in both groups.