Fixateur externe monolatéral pour fracture diaphysaire du tibia avec mesures des contraintes sur le fixateur. [Strain gauge measurements on a one-side external fixation: a prospective series of 11 tibial shaft fractures]

PURPOSE OF THE STUDY: External fixation is often the treatment of choice for open complex fractures of the tibia. For closed tibial shaft fractures, it is generally a second choice alternative. The purpose of this study was to determine whether fusion of closed and open fractures of the tibia can be successfully achieved with a one-side external fixator equipped with strain gauges and to evaluate complications of this type of treatment. MATERIAL AND METHODS: A consecutive series of 11 mid shaft fractures of the tibia (4 closed fractures and 7 Gustilo grade I and II open fractures) in 11 patients (mean age 29 years) were treated with a one-side external fixator. Strain was measured weekly to adjust the treatment. A Sarmiento walking cast was applied in all cases 4 weeks after removal of the external fixator. RESULTS: All 11 fractures healed without complications and without pin tract infection. Mean delay to consolidation was 20.5 weeks (range 13 - 29.5 weeks). One patient required a revision procedure for decortication and bone graft at 12 weeks. Weight bearing (50% of body weight on the injured limb) was achieved at 6.7 weeks (mean) and total weight bearing at 11.9 weeks. The external fixator's strain curves were compatible with normal healing in 3 cases, with slow healing in 3 and with retarded healing in 3 others. Two of the curves did not show recognizable patterns despite a favorable clinical and radiological course to healing. DISCUSSION: Early detection of a pathological pattern of fracture healing followed with a strain gauge enabled adaptation of treatment in all cases. Decortication with bone grafting was necessary in one patient. In two other cases, compression of the fracture with the external fixator or dynamic locking were sufficient to achieve a favorable healing pattern. This small series demonstrated that bone healing can be achieved within usual delays with external fixation and without major complications. Use of strain gauges on the external fixator allowed early detection of retarded healing and subsequent modification of the treatment protocol. This type of treatment might be an interesting therapeutic alternative for the treatment of closed fractures of the tibial shaft