Characteristics, management, and outcomes of spontaneous osteonecrosis of the knee in Indian population.

Abstract

Spontaneous osteonecrosis of the knee affects the medial femoral condyle in patients above 55years of age. Many reports and studies are available from western countries. But there is a gross paucity of literature on spontaneous osteonecrosis of the knee (SPONK) in the Indian subcontinent, either it is under-reported or detected at a later stage. The aim of our study was to detect SPONK in Indian population and describe its characteristics, treatment, and outcome. A prospective study was conducted over a period of threeyears. All patients above 18years with knee pain at rest and medial condyle tenderness without joint laxity were evaluated with plain radiographs and MRI. Further tests were done if radiological signs of osteonecrosis were present. Various parameters were recoded like Visual Analog Scale (VAS), Knee Society Score (KSS), and MRI Osteoarthritis Knee Score. Conservative treatment consisted of a combination of NSAIDs and bisphosphonates. Decompression with bone grafting was done if there was no improvement or deterioration at threemonth follow-up. Ten patients were diagnosed with SPONK. The mean age was 50years with male predominance (60%) with the involvement of medial femoral condyle (80%) or left knee (70%). Most cases were in Koshino stage 1. Mean VAS was 6.5 and mean KSS was 59. All clinical parameters showed improvement at oneyear. A study with a bigger sample size and longer follow-up is needed to fill the lacunae of literature on this topic from the Indian subcontinent. In spite of the limitations, we did observe that in our population, males were more commonly affected than females, which is contrary to most studies on the subject. Also, the disease had an early age of onset (50years) in Indian population as compared to Western and East Asian populations. Combined therapy of NSAIDs and bisphosphonates shows excellent results over a period of oneyear. Joint-preserving surgeries are effective even in Koshino stage 3 SPONK.