Spontaneous Osteonecrosis of Knee: A Case Report.

A 49-year-old man with no prior history of trauma, steroid use, or alcohol consumption presented with spontaneously developing progressive left knee discomfort that worsened after intense activity for 1.5 years. Normal x-rays indicated local discomfort along the joint line, and magnetic resonance imaging (MRI) revealed a T1-weighted hypointense line with bone infarcts in the medial and lateral condyle and the lower part of the left femur in addition to diffuse bone edema. Spontaneous osteonecrosis of the knee (SONK) was identified. Initially, he was treated conservatively with painkillers and calcium supplements. Then, the patient showed a significant improvement.