Usually more than 55 years, more common in females (3:1)
Not associated with other joint lesion
No risk factors known
99% unilateral
Usually unicondylar - medial femoral condule more common than lateral; may be adjacent tibial condyle
Present with sudden onset of pain
Plain radiography: (Aglietti, modification of Koshino classification)
Stage I: Normal. MRI or bone scan positive.
Stage II: flattening of weightbearing surface of condyle.
Stage III: radiolucent area surrounded by sclerosis.
Stage IV: ring of sclerosis, subchondral bone collapse, sequestrum, fragment.
Stage V: Narrowing of joint space, osteophyte, femoral and/or tibial subchondral sclerosis.
MRI:
Management:
Good results with conservative management, include protected weightbearing, analgesics, physiotherapy causing strengthening of quadriceps and hamstrings
Orthoscopic debridement has mixed results
Osteochondral allografts have disappointing results
High tibial osteotomy have encouraging results
Core decompression has some success
Unicondylar arthroplasty
Total knee replacement
Prognosis:
Worse prognosis in lesions greater than 5 sq.cm have worse prognosis, in lesions occupying greater than 50% of femoral condyle, in advanced stage lesions.
Reference:
1. Rajadhyaksha et al. e-medicine
Journal Watch: Click Here
