Spontaneous Osteonecrosis of the Knee in the Elderly over 60 Years Old / 대한정형외과학회잡지

ABSTRACT

PURPOSE: This study examined the results of treatment according to the stage and size of a spontaneous osteonecrosis lesion of the knee (SONK) in the patients over 60 years of age. MATERIALS AND METHODS: Twenty-two knees from 19 patients over 60 years of age were treated for spontaneous osteonecrosis of the knee at our institution between January, 2000, and June, 2004. The mean follow time was 20.7 months. The condylar ratios, proportion of the lesion size to the condyle were measured. The size was obtained by multiplying the values from the anteroposterior and lateral radiographs. The stages were classified radiographically, and the treatment results were analyzed according to the size and stage. Conservative treatment was performed if the ratio and size were 40% or 5.0 cm2. A paired T-test, Spearman correlation test and Wilcoxon test were used for the statistical evaluation. RESULTS: There was a higher prevalence in females (15 patients, 79%), and the mean age was 65 years (46-77 years). Bilateral involvement was observed in 3 patients. The lesions involved mainly the medial femoral condyle (21 cases, 95%). Seven cases (31%) had a condylar ratio 40%. Conservative treatments were performed in 5 cases staged radiographically as I or II and there were no significant changes in the knee scores (p=0.931). Of the 17 cases staged III and IV radiographically, conservative treatment and arthroplasty were performed in 7 and 10 cases, respectively. Seven cases, in whom conservative treatments had been performed, showed a decreased in the knee scores compared with the increased knee scores in 10 patients treated with arthroplasty (p=0.943). CONCLUSION: An accurate diagnosis and measurement of the size and staging of spontaneous osteonecrosis of knee in patients over 60 years of age is important for proper treatment. Clinically, no further progression of symptoms is visible on grade I and II spontaneous osteonecrosis of the knee after conservative treatment. However, arthroplasty improves the clinical results in patients with radiological grade III and IV osteonecrosis compared with conservative treatment.