Subchondralgia Case Summary

Case Presentation
A 58-year-old presented with complaint of pain in his leg and was unable to walk.
Past history.
• One year back, he fell from a ladder and suffered a left acetabular fracture. His injury was managed conservatively and he was able to walk without pain. After 6 months, he developed left coxalgia and was unable to walk, he visited the hospital after onset of pain.
• He also had a past history of hepatic cirrhosis due to hepatitis C, for which he had undergone a living liver transplantation 12 years back.
• After liver transplantation, he had not consumed alcohol and there was no history of corticosteroid therapy.
Laboratory tests
Plain radiography and computed tomography (CT) images revealed a fused acetabular fracture and collapsed

The resected femoral head demonstrated a flattened widespread surface with a flap of articular cartilage and subchondral bone, and the cut section showed a subchondral fracture line parallel to the articular surface (Figure 4A).
Histological examination showed repair tissue comprising of marked fracture callus and vascular rich granulation tissue on both sides of the fracture line (Figure 4B). There was no evidence of antecedent osteonecrosis. Histopathologic findings demonstrated that the collapse of his femoral head was caused by a subchondral fracture resulting from acetabular fracture. Figure 4 Histological findings show a subchondral fracture of the femoral head and no evidence of antecedent osteonecrosis. (A) Mid-coronal cut section of the resected left femoral head shows a linear fracture line paralleling the subchondral bone endplate. (B) The photomicrograph obtained from the subchondral fractured lesion shows marked fracture callus and vascular rich granulation tissue (hematoxylin and eosin, ×100).

Learning points
Preventing post-traumatic osteoarthritis is a challenging problem in patients with acetabular