Comparison of clinical, imaging and second-look arthroscopic outcomes between varus knee patients with and without preoperative tibial varus deformity after medial opening-wedge high tibial osteotomy

Abstract

PurposeThis study aimed to compare the regeneration status of articular cartilage, clinical, and radiologic outcomes between varus knee patients with and without preoperative tibial varus deformity (PTVD) after medial opening-wedge high tibial osteotomy (OWHTO) MethodsVarus knee patients who had undergone OWHTO were divided into two groups according to preoperative medial proximal tibial angle (MPTA): a great varus (GV) group (MPTA <85°) and a mild varus (MV) group (85°≤preoperative MPTA <87°). The hip–knee–ankle (HKA) angle, weight-bearing line ratio (WBL%), MPTA, joint line convergence angle and joint line obliquity were measured. Second-look arthroscopy was undertaken 24 months after HTO. The Knee Society (KS) function score and knee score, and Lysholm score were used to evaluate the functional outcomes. All parameters were evaluated preoperatively and 24 months after HTO. ResultsThe GV group had greater varus than the MV group in HKA and WBL% before surgery, but greater valgus after surgery. The arthroscopic probe before HTO revealed the advanced chondral damage in the GV group and lighter chondral damage in the MV group. The regeneration of medial femoral condyle was considerably more frequent in the GV group (72.5%, 45/62) than in the MV group (50.0%, 27/54) (P = 0.030). No significant differences were observed in all functional outcomes preoperatively and 24 months after HTO. ConclusionThe extent of cartilage regeneration in patients without PTVD was inferior to that in those with PTVD, but the functional outcomes were comparable. OWHTO may be a treatment option in a selected subset of varus knee patients without PTVD.