Osteochondritis dissecans (OCD) is a condition of the joints that appears to primarily affect subchondral bone, with secondary effects on articular cartilage. Initially, softening of the overlying articular cartilage is noted with an intact articular surface; this can progress to early articular cartilage separation, partial detachment of an articular lesion, and eventually osteochondral separation with a loose body. Etiologic theories of traumatic, ischemic, accessory ossification center persistence and various genetic factors have been proposed [1
Several investigators have shown subsequently that there is an increased occurrence of OCD lesions of the lateral femoral condyle associated with a discoid lateral meniscus [6
]. A discoid lateral meniscus might play an important role in causing OCD of the lateral femoral condyle among patients who are still growing. Repetitive abnormal stress on weaker osteochondral structures produced by a discoid meniscus during growth may cause OCD of the lateral femoral condyle. Given the potential for healing, conservative management is indicated for stable OCD in patients who are skeletally immature. However, patients with OCD of the lateral femoral condyle combined with a discoid lateral meniscus often have persistent symptoms despite conservative management [8
We present a case of OCD of lateral femoral condyle combined with a discoid lateral meniscus, which healed after meniscoplasty for the symptomatic lateral discoid meniscus without surgical intervention for the OCD.
A seven-year-old Korean girl presented with left knee pain of three months' duration. A physical examination demonstrated a five-degree extension block and tenderness on the lateral joint line. The result of a McMurray test was positive. An MRI scan revealed a complete discoid lateral meniscus with a bucket handle tear. On arthroscopy, a complete discoid lateral meniscus with longitudinal tear was found that extended throughout the entire meniscus. Subtotal meniscectomy with reshaping of remnant meniscus tissue was performed. Our patient had no further symptoms stemming from the torn meniscus and recovered a full range of motion. Activity was not restricted following recovery from the surgical intervention.
Two years after her first operation, our patient presented with a snapping sound and intermittent pain involving her right knee. A physical examination at this time revealed mild tenderness to the lateral joint line, but all other test results and findings from plain radiographs were normal. An MRI scan showed a complete discoid lateral meniscus with a 1.5 by 1.5 cm osteochondral lesion involving the posterior articular surface of the lateral femoral condyle (Figure ). There was no evidence of fluid signal intensity between the host and fragment on a T2-weighted MRI scan (Figure ). Initially, our patient was treated with conservative management consisting of activity modification. However, our patient had persistent symptoms despite six months of conservative management and she therefore underwent operation. On arthroscopy, a complete discoid lateral meniscus was identified (Figure ). The articular surface of the lateral femoral condyle had normal articular continuity and contour, but softening of cartilage at the margins of the OCD within the lateral femoral condyle without breach or fibrillation was found. We performed meniscoplasty that provided a stable 6 mm peripheral of the remaining meniscus and no treatment was performed for the OCD lesion (Figure ). Post-operatively, our patient was allowed to begin full weight bearing without immobilization and started a physical therapy protocol to improve the range of motion in her knee. Five months after the operation, an MRI scan demonstrated complete resolution of the previous OCD lesion of the lateral femoral condyle (Figure ). There was no restriction of early activity following the surgical intervention. Our patient had no symptoms on either knee and had returned to full daily activity.
Figure 1 (A, B) MRI study showing a discoid lateral meniscus with a 1.5 by 1.5 cm osteochondral lesion involving the posterior articular surface of the lateral femoral condyle. (C) There was no evidence of fluid signal intensity between host and fragment on a (more ...)
(A) Arthroscopic picture showing a complete type of discoid lateral meniscus of right knee joint and (B) meniscoplasty with a stable 6 mm peripheral remaining meniscus.
Our patient five months after operation. MRI study showing complete healing of the osteochondritis dissecans lesion of the lateral femoral condyle.