Introduction
Epidemiology
- Incidence: 1.00 cases per 100,000 person-years
- Peak incidence: 6-15 years
- Sex ratio: more common in males 3:1
Condition | Relative incidence |
---|---|
Osgood-Schlatter disease | 200.00 |
Osteochondritis dissecans | 1 |
<1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Aetiology
- Trauma
- Male
- Genetic
Clinical features
- Knee pain and swelling, typically after exercise
- Knee catching, locking and/or giving way - more constant and severe symptoms are associated with the presence of loose bodies
- Feeling a painful 'clunk' when flexing or extending the knee - indicating the involvement of the lateral femoral condyle
Signs:
- Joint effusion
- Full range of movement in the joint without signs of ligamentous instability
- External tibial rotation when walking - if medial femoral involvement
- Tenderness on palpation of the articular cartilage of the medial femoral condyle, when the knee is flexed
- Wilson's sign for detecting medial condyle lesion - with the knee at 90° flexion and tibia internally rotated, the gradual extension of the joint leads to pain at about 30°, external rotation of the tibia at this point relieves the pain
Investigations
Investigations:
- X-ray (anteroposterior, lateral and tunnel views) - may show the subchondral crescent sign or loose bodies
- MRI - used to evaluate cartilage, visualise loose bodies, stage and assess the stability of the lesion
- CT - may be used in preoperative planning and in cases where MRI is not available or contraindicated
- Scintigraphy - may be used to guide treatment as it may show increased uptake in the fragments - a sign of osteoblastic activity