Review Question - QID 8765

This patient has a tibial non-union with an intact fibula. Fibular osteotomy or ostectomy can increase the amount of compression at the tibial non-union site that occurs with weight-bearing.

If a healed or intact fibula is effectively longer than a fractured and/or non-uniting tibia then the fibula may prevent tibial healing. A fibular fracture associated with a tibia fracture usually heals within 6 weeks, and therefore is often healed by the time delayed union of the tibia is diagnosed. If compression across a tibia fracture is to occur with an intact fibula, some force must be used to deform the fibula before tibial compression can occur, unless the fibula has healed in a shortened position. Fibular osteotomy or ostectomy can address this length mis-match and help achieve union.

Teitz et al. reviewed 550 patients with tibial fractures, 111 of which had intact fibulae treated with either a long cast, short cast, patellar tendon bearing cast or external fixation. There was a 26% non-union rate in adult (age >20) patients with tibial shaft fractures with intact fibulae. They also found that, biomechanically, tibiofibular length discrepancy caused altered strain patterns for tibia, fibula and ankle. They concluded that in older patients, the intact fibula results in greater incidence and severity of complications.

DeLee et al. reviewed 67 patients with un-united tibia fractures at 20 weeks. 51 patients were treated with partial fibulectomy 20 to 24 weeks. The partial fibulectomy (2.5 cm of fibula) was performed remote from the tibial fracture and fibulectomy (rather than osteotomy) done to prevent fibular healing occurring before tibial union, and yet not to create gross instability. This resulted in union in 77% of cases. They concluded that early fibulectomy minimized morbidity and decreased the need for bone grafting, while leaving the tibial fracture site undisturbed, should future bone-grafting be necessary.

Figure A shows an isolated tibial fracture with intact fibula. Illustration A shows examples of partial fibulectomy for treatment of tibial non-union after casting (a), nailing (b and c) and external fixator treatment (d).

Incorrect answers:
Answer 1. Cast application or further observation is unlikely to alter the outcome at this point.
Answer 2. Solid nails have not been shown to affect healing rates.
Answer 4. BMP-3 has no osteoinductive activity.
Answer 5. There is not a large bone defect at the non-union site that would indicate the need for an induced membrane technique.