Avulsive cortical irregularity of the distal femoral condyles in children

Radiographs of 339 distal femora taken for variable reasons in 221 patients between 0 to 21 years of age were reviewed. Focal lytic change and/or sclerotic irregularity were present at the posterior cortex of the medial distal femoral condyles in 9.1 % of the males and in 5.5 % of the females. There were no positive cases in the patients over 17 years of age. CT scan was performed in one case in which bilateral lesions were present at the insersion sites of the gastrocnemius muscles. Bone scintigraphy was performed in 2 cases and was negative in both. Although many of the positive cases presented with mild to moderate degree of pain around the knee joints, this condition was self-limiting. It was considered that these lesions were probably caused by the tension of the gastrocnemius muscle due to excessive activity of the patients in this age. (author)