Open-wedge high tibial osteotomy for spontaneous osteonecrosis of the medial tibial plateau shows excellent clinical outcomes.

PurposeThere have been few reports on medial tibial plateau osteonecrosis, and treatment options remain controversial. This study aimed to evaluate the clinical outcomes of open-wedge high tibial osteotomy (OWHTO) for osteonecrosis of the medal tibial plateau.MethodsPatients who underwent OWHTO for spontaneous osteonecrosis of the medial tibial plateau from November 2013 to September 2017 at our institution and followed up for at least 2 years after surgery were included in this study. Patients with history of alcohol abuse and corticosteroid therapy were excluded. Clinical evaluations, including the Japanese Orthopedic Association (JOA) score and the Oxford Knee Score (OKS), were measured preoperatively and at the final followup. Radiological evaluations included the weight-bearing line ratio (WBLR) and the lesion stage of the osteonecrosis according to Carpintero, Lotke, and the modified Ficat and Arlet classification. The area and size of the necrosis and the type of meniscus tear were also evaluated using preoperative magnetic resonance imaging (MRI). Additionally, cartilage regeneration was evaluated at plate removal.ResultsTwelve cases that underwent OWHTO for spontaneous osteonecrosis of the medial tibial plateau were enrolled. Eleven cases had isolated medial tibial osteonecrosis, and one case had both femoral and tibial osteonecrosis. The mean age was 59.6 +/- 9.0 years, and the mean follow-up period was 41.8 +/- 17.6 months.The WBLR significantly changed after OWHTO (24.0% +/- 10.7% to 66.3% +/- 6.7%, P < 0.001), and all clinical scores significantly improved after surgery: JOA score 63.3 +/-12.3 to 95.0 +/- 4.8, OKS 27.4 +/- 7.8 to 42.6 +/- 4.1, both 0.001. There were no adverse complications requiring additional surgery. The MRI findings revealed that all cases had meniscal lesions in addition to a necrotic lesion. Second-look arthroscopy was performed at plate removal in 11 cases, and cartilage regeneration was observed in 9/11 cases (81.8%).ConclusionsThis study's results demonstrated that OWHTO is an effective procedure for spontaneous osteonecrosis of the medial tibial plateau with respect to subjective and objective clinical outcomes.