Background: There is little information
on the natural history or treatment of osteochondromas arising from
the distal aspect of either the tibia or the fibula. It is believed
that there is a risk of deformation of the ankle if these exostoses
are left untreated or if the physis or neurovascular structures
are injured during operative intervention.
Methods: We reviewed the records of twenty-three
patients who had been treated for osteochondroma of the distal aspect
of the tibia or fibula between 1980 and 1996. Four of the patients
had hereditary multiple cartilaginous exostoses. There were seventeen
male and six female patients, and the average age at the time of
presentation was sixteen years (range, eight to forty-eight years).
Results: Preoperative radiographs showed evidence
of plastic deformation of the fibula in eleven patients who had
a large osteochondroma. Four patients elected not to have an operation.
The tumor was excised in nineteen patients. Postoperatively, all nineteen
patients had a Musculoskeletal Tumor Society score of 100 percent
for function of the lower extremity with pain-free symmetrical and unrestricted
motion of the ankle at the latest follow-up examination. Partial
remodeling of the tibia and fibula gradually diminished the asymmetry of
the ankles in all nineteen operatively managed patients; however,
the remodeling was most complete in the younger patients. Pronation
deformities of the ankle did not change after excision of the tumor.
Complications of operative treatment included four recurrences (only
three of which were symptomatic), one sural neuroma, one superficial
wound infection, and one instance of growth arrest of the distal
aspects of the tibia and fibula.
Conclusions: Osteochondromas of the distal and
lateral aspects of the tibia were more often symptomatic than those
of the distal aspect of the fibula; they most commonly occurred
in the second decade of life with ankle pain, a palpable mass, and
unrestricted ankle motion. Untreated or partially excised lesions
in skeletally immature patients may become larger and cause plastic
deformation of the tibia and fibula and a pronation deformity of
the ankle. Ideally, operative intervention should be delayed until
skeletal maturity, but, in symptomatic patients, partial excision
preserving the physis may be necessary for the relief of symptoms
and the prevention of progressive ankle deformity. However, partial
excision is associated with a high rate of recurrence, so a close
follow-up is required. Skeletally mature patients who are symptomatic may
require excision of the tumor.