|
Year |
2002 |
|---|---|
|
Question Number |
234 |
|
Category |
Pediatric Orthopaedics |
Question
A 9 yr old boy has activity related pain at the medial joint line of his knee. He denies locking or effusion. A radiograph is shown in Fig. 66. Management should consist of:
1. arthroscopic partial menisectomy
2. excisional biopsy
3. osteochondral graft
4. activity restrictions
5. periosteal transplantation
Figures
Answer (click for answer)
Preferred Answer: 4
Figure 66 shows the patient has osteochondritis dissecans. Most of these lesions are located on the lateral side of the medial femoral condyle and range from a few millimeters to a centimeter or more in diameter. In fig. 66, the small crater like area on the lateral aspect of the medial femoral condyle is the lesion. The exact etiology has not been determined. The most common presenting complaint is nonspecific knee pain. They may report aching pain in the parapatellar area that is aggravated by activity. If the fragment has become loose they may note crepitance, popping, giving way or even locking.
Usually, physical findings are minimal. There may be mild parapatellar tenderness, slight quad atrophy and slight pain with ROM. There may be specific tenderness found along the medial border of the patella with the knee flexed as the lesion is most commonly located on the lateral aspect of the medial femoral condyle. Usually the lesion can be seen on plain radiographs-especially on the tunnel view. CT can show more clearly if the lesion is detached, or MRI can also show this. *Arthroscopy is the most reliable method of determining the status of the lesion.
Treatment: Initially it is observation and activity restrictions. In kids with open growth plates the lesions usually heal spontaneously over several months. If symptoms persist or the child is not sufficiently limiting activity, casting or bracing may be tried making sure there is no weight bearing across the lesion. If symptoms still persist, then order a bonescan, CT or MRI. Then, arthroscopy is indicated. An intact lesion may be left alone or drilled to promote healing. In the early separated lesion in-situ pinning is preferred. If the lesion is partially or fully detached, the fragment may be replaced and pinned. If the bed is not salvageable, the crater may be managed in several ways. Spongialization is the preferred technique which involves removing all the fibrous tissue and underlying subchondral bone until bleeding cancellous bone is reached. Another method is trephining, in which the edges of the defect are cut at right angles to the articular surface. This enhances uniform growth of fibrocartilage into the defect without interfering with the normal articular surface. Finally-saucerization, in which the edges of the defect are tapered, is NOT RECOMMENDED.
Reference: Herring, JA:Disorders of the knee, in Herring, JA (ed): Tachdijian’s Pediatric Orthopedics, ed 3, 2002, pp 789-838.