Mid-term survival and physiological joint angles after double level osteotomy of severe varus osteoarthritis.

Abstract

Double-level osteotomy (DLO) is a joint-preserving technique for the treatment of symptomatic varus knee osteoarthritis (OA) in cases of femoral and tibial combined deformity. The study aimed to investigate the mid-term survival rate (>5 years) and restoration of postoperative joint angles. Sixty-five knees underwent DLO (medial open wedge high tibial osteotomy (MOWHT) and lateral closing wedge distal femoral osteotomy (LCWDFO) between 2011 and 2015. Minimum follow-up was 5 years. The survival rate was recorded and, in case of conversion to knee arthroplasty, the time of conversion. Radiographs were obtained preoperatively, 6 weeks postoperatively and at the last follow-up. On radiographs mechanical tibiofemoral angle (mTFA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal femur angle (mLDFA), joint line convergence angle (JLCA) and joint line obliquity (JLO) were measured. The clinical outcome was measured using International Knee Documentation Committee (IKDC), Oxford and Lysholm score. Forty-nine knees (75% follow-up) were included after 8.0 ± 1.4 years. At the last follow-up, six knees underwent arthroplasty (7-year survival rate: 91.8%; 5-year survival rate: 93.9%) in average after 5.1 ± 2.3 years. Preoperatively, there was a varus deformity of -10.0 ± 2.5° (mTFA). In addition, pathologic knee joint angles with an mMPTA of 84.7 ± 2.2°, an mLDFA of 91.4 ± 2.1°, an JLCA of 3.4 ± 1.8 and a JLO of 3.0 ± 1.9°. Six weeks postoperatively mTFA was 0.7 ± 2.2° with values of mMPTA 91.0 ± 2.3°, mLDFA 86.8 ± 2.0° and JLO of 2.8 ± 2.1°. In the mid-term, a preserved leg axis (mTFA: -0.9 ± 2.7°) and preserved joint angles (mMPTA: 90.3 ± 2.7°, mLDFA: 87.1 ± 2.3°, JLCA: 4.3 ± 1.9 JLO: 3.2 ± 2.1°) were observed. At the last follow-up, the IKDC, Oxford Knee Score (OKS) and Lysholm score were: 61.2%, 36.1 points and 78.3 points, respectively. The study demonstrates that DLO is an effective surgical technique to restore physiological joint angles in patients with severe preoperative deformity and symptomatic varus OA. Mid-term results indicate good clinical outcomes and a low conversion rate to TKA. Level IV.