Management of nonunion of lower-extremity long bones using mono-lateral external fixator--report of 37 cases.

INTRODUCTION: The management of nonunion has remained a constant challenge. The associated bone defect, shortening, deformity and infection complicate the management. A mono-lateral external fixator may minimise some of the problems frequently encountered in these patients. We report our results of prospectively evaluated 37 consecutive patients regarding nonunion of lower-extremity long bones managed using a mono-lateral external fixator.

PATIENTS AND METHODS: A total of 37 patients (7 femurs and 30 tibias), mean age 36 years, were stabilised using a mono-lateral fixator for nonunion of long bones. The mean time since injury was 8 months. Fifteen cases were infected and they received debridement and antibiotic treatment as per culture and sensitivity reports. In cases where the bone gap or shortening was >3 cm in the tibia and >5 cm in the femur, corticotomy and bone transport (bifocal procedure) was done and in the remaining cases, only compression-distraction (monofocal procedure) was done. The bone and functional results were assessed at the end of treatment according to the criteria described by Paley et al.

RESULTS: Union was achieved in 34 cases (91.9%). The average time for union was 5 months. Five cases were treated with the bifocal method and 32 cases were treated with the monofocal method. The average length gain in the bifocal method was 5.7 cm, mean duration of treatment was 8.2 months and bone healing index (BHI) was 1.44 months cm(-1). In six cases, the monofocal treatment was used for limb lengthening. The average length gain was 1.9 cm, mean duration of treatment was 4.83 months and BHI was 2.5 months cm(-1). Bone grafting was required in two cases at the docking site. The bone results were excellent in 24 cases, good in nine cases, fair in one case and poor in three cases. The functional results were excellent in 27 cases, good in six cases, fair in one case and poor in three cases. The most common complication in this series was pin-tract infection (11.5%).

CONCLUSIONS: A mono-lateral external fixator is an effective method for treating nonunion in the lower extremity with or without bone loss. The nonunion site can be carefully controlled with simultaneous correction of angulation and length.