Loss of lateral femoral condyle following sepsis of knee region in infancy: The hypothesis of vascular pathogenesis and clinical course

Complete loss of lateral femoral condyle of the femur following sepsis of the knee region in infancy is a well-recognized entity. The etiopathogenesis of the sequelae is poorly understood with synovial plicae and post-septic growth disturbance postulated as possible causes. Two illustrative cases are presented to elucidate the clinical effects of condylar loss in the pediatric age group.There is a typical pattern of unicondylar damage, loss of adjacent metaphysis, and metaphyseal spur in involved cases. Abnormal loading of the knee, ligament laxity, and the presence of a physeal bar contribute additionally to deformity. The deformity progression can be as rapid as 2.8 degrees per month. The lesion is most often treated by balancing the knee mechanics using osteotomies and growth modulations. The lesion progresses downhill due to the absence of lateral support of the knee joint configuration. The anatomical region supplied by the superior lateral genicular vessels closely matches with the lateral unicondylar femoral loss seen post-sepsis. A vascular etiology is therefore hypothesized for the lesion.