The aim of this study was to assess the incidence of fibula non-union in patients undergoing distraction osteogenesis, and the incidence of symptoms following this.

A consecutive series of 58 patients undergoing distraction osteogenesis at a tertiary centre under a single surgeon were included. Data was collected prospectively. Plain radiographs were reviewed retrospectively by a blinded reviewer. Union was defined as the presence of bridging callous on two views.

There were 58 distraction procedures performed. The mean age was 37.2 years (range 16.0 to 80.6). There were 36 males and 22 females. The mean follow-up was 23.4 months (4–70 months)

9 (15.5%) went onto non-union at frame removal. 3 (33.3%) of the 9 fibulas that did not unite developed symptoms. 2 (66.7%) of these required surgery in the form of fibula plating. Both of these patient's symptoms resolved following surgery. 3 (33.3%) of the 9 non-united fibulas also had tibial non-union compared to 1 of the 49 where the fibula united.

There was no association between location of fibula osteotomy and development of non-union. 35 fibula osteotomies were performed in the third quarter.

Of the fibulas that united, the mean fibula lengthening was 9.25 mm (range 1.2–27.8 mm). In the fibulas that went onto non-union the mean lengthening was 23.66 mm (range 5.1–51.5 mm) (P = 0.004).

54 (93.1%) of the tibias united following osteotomy and distraction, whilst 4 (6.9%) went onto non-union requiring operative treatment. Of the 4 tibias that did not unite, 3 (75%) also had fibula non-union (P = 0.01).

Fibula non-union is a relatively common complication following osteotomy in distraction osteogenesis. The length of fibula distraction and tibia non-union are significant risk factors for the development of a fibula non-union. We recommend surgical intervention for those patients who have symptomatic fibula non-unions.