Radiographic finding vary depending on the stage of the disease.Arnold and Hilgartner have proposed a 5 stage classsification for biny changes
- Soft tissue swelling.
- Osteoporosis, epiphysial overgrowth but joint integrity maintained.
- Disorganisation joint, subchondral cysts, squaring of patella (Jordan’s sign), inter-condylar widening, enlarged femoral condyles that appear to fall off the patella.
- Narrowing joint space and cartilage destruction.
- Marked narrowing joint and fibrous capsular contracture leading to decreased range of movement.
Magnetic resonance imaging, computed tomography and ultrasound scans may all be useful.