Complicated Fracture and Resorption of an Osteochondroma.

ABSTRACT

Aims: To describe two unusual complications of a typical solitary pedunculated femoral osteochondroma that included a distal fracture of the exostosis and a missed fragment following surgical treatment as well as to evaluate the progress of the untreated free fragment at follow-up. Case Presentation A 13-year-old boy consulted for a painful bruising of the medial side of the right knee following injury. Radiological survey indicated a pedunculated osteochondroma of the distal femoral metaphysis but there was no evidence of a fracture line. Surgical removal of the lesion was uncomplicated but the post-operative radiographs indicated an osteocartilaginous portion of the osteochondroma missed in the thigh musculature. No further surgical intervention was undertaken. Radiographic followup revealed gradual regression and complete resorption of the free fragment 3 years later. No complications have been recorded at the most recent follow-up, 10 years later. Discussion: Fracture through the base or stalk of a pedunculated osteochondroma is a rare complication but the diagnosis of a distally fractured exostosis has not been previously reported. Regression or resorption of a solitary pedunculated osteochondroma following a fracture is also very rare. Although recurrence of the lesion in the reported patient would be very likely, complete resorption was evident instead within 3 years. Conclusion: An obscure distal fracture of a penduculated osteochondroma may be suspected in cases that a clinical diagnosis of a fractured exostosis is not associated with the radiographic detection of a fracture line through its stalk. Radiographic control during surgery is necessary to ensure complete removal in cases with a clinically, or even radiologically, diagnosed fractured exostosis. Surgical excision of a distally fractured osteochondroma may be avoided, since complete resorption of the distal fragment may be evident in a few years.