Multiple hereditary osteochondromata.

Multiple hereditary osteochondromata is a disorder consisting of multiple projections of bone (exostoses) capped by cartilage. The lesions are most numerous in the metaphyses of long bones but may appear on diaphyses of long bones and on flat bones and vertebrae. The transmission is autosomal dominant. Sarcomatous transformation is uncommon and probably occurs in fewer than 1% of patients. The more common indications for surgical excision of lesions are pain, growth disturbance, compromised joint motion, cosmesis, and secondary impingement of tendon, nerve, or vessel. Excision of the lesions is effective in relieving pain, improving cosmesis and joint motion, and removing secondary impingement of tendon, nerve, or vessel, and may retard or prevent progressive disturbance of osseous growth. Wrist and ankle deformities are often associated with relative shortening and bowing of the ulna and fibula, respectively; tilt and tapering of the distal radial and tibial epiphyses; and distal radioulnar and tibio-fibular diastasis. These deformities can be effectively treated by ulnar and fibular lengthening combined with hemiphyseal stapling of the distal radius and tibia. Progressive genu valgum is well corrected by placement of staples over the medial side of the physis of the distal femur or proximal tibia or both.