Bilateral Osteochondritis Dissecans of the Knees in Monozygotic Twins: The Genetic Factor and Review of the Etiology

Abstract not available. Introduction provided instead.

Osteochondritis dissecans (OCD) is an idiopathic lesion of subchondral bone that results in delamination and sequestration, which can occur with or without articular cartilage involvement and instability.¹ The incidence of this condition, which has juvenile and adult forms, has increased recently because of the growing participation in competitive sports by children of both sexes at younger ages.² The majority of cases of adult OCD are thought to result from persistence of an unresolved juvenile OCD lesion, though the literature includes reports of adult OCD lesions arising de novo.²

Sir James Paget³ first described an OCD lesion in 1870 as a “quiet necrosis.” In 1888, König⁴ suggested the term osteochondritis dissecans. He thought that trauma caused necrosis of part of the articular surface, and he described “dissecting inflammation,” which followed the trauma and eventually led to fragment separation.⁵

Although there are several other postulated causes, including inflammation, genetics, ischemia, ossification, and repetitive trauma, there is not enough evidence to conclusively support any of these as the etiologic basis of OCD.¹

The occurrence of OCD in more than one family member is unusual and lends credence to the suggestion that, in such cases and particularly in polyarticular OCD, there is an underlying constitutional or developmental factor.⁶

We present the case of 11-year-old monozygotic twins with bilateral OCD of the medial femoral condyles and review the literature concerning the genetic factor. We are not aware of any similar cases reported in the literature.