Abstract
BACKGROUND: The aim of this study is to determine whether the volume of the osteonecrotic lesion in spontaneous osteonecrosis of the knee (SONK) or other prognostic factors predict progression to total knee arthroplasty (TKA). The secondary aim is to analyse co-relation of volume of osteonecrotic lesion versus other prognostic factors The authors hypothesize that a greater osteonecrotic volume predicts progression to TKA. MATERIALS AND METHODS: A retrospective study was conducted at a single tertiary hospital. All patients under the care of a single surgeon with magnetic resonance imaging (MRI)-proven SONK were included from the period of January 2011 to January 2018. Survival analysis was conducted to evaluate for progression to TKA based on volume and location of osteonecrotic lesion. Univariate and multivariate analyses were performed to identify potential risk factors for TKA. RESULTS: 42 patients with MRI-proven SONK were evaluated. 9 patients (21.4 %) required TKA. There was no significant association between progression to TKA with volume of the osteonecrotic lesion. Other factors such as age, gender, body mass index, degree of bony edema and cartilage damage, presence of meniscal tear and subchondral fractures and location of osteonecrotic lesion were also not significant. CONCLUSION: The volume of the osteonecrotic lesion and other evaluated prognostic factors were not predictive of the progression to TKA for patients with SONK.