Pelvic support osteotomy for unstable hips using hybrid external fixator: case series and review of literature.

BACKGROUND Instability of the hip joint is a source of great discomfort to the patient due to pain, limp and leg-length discrepancy. Pelvic support osteotomy with Ilizarov hip reconstruction, along with its various modifications, has emerged as a standard treatment modality for this difficult problem. We present a series of patients with unstable hips treated with a modification of the monolateral fixator-the hybrid external fixator. MATERIALS AND METHODS A retrospective review of a series of 23 patients (38 hips) with unstable hips treated at our institute with the hybrid external fixator was performed. The mean age of the patients was 19.1 years (range 7-49 years). The outcomes were evaluated radiologically and clinically using the Harris hip score. RESULTS After a mean follow-up period of 30.5 months (range 10-91 months), the range of motion of the hip had improved, pain had decreased, and the Harris hip score had improved from 63.43 to 75.17, which was statistically significant. The pre-operative knee range of motion was achieved in all patients by the last follow-up. Trendelenburg gait disappeared in all patients except for 3, limb length discrepancy improved from a pre-operative mean of 43 mm to a post-operative mean of 5 mm at final follow-up, and the mechanical axis was regained in all patients. Pin-tract infections were the commonest complications, occurring in 12 patients (52%). CONCLUSIONS This study shows that pelvic support osteotomy using the new hybrid external fixator, which combines the versatility and modularity of the Ilizarov frame with the compactness of the monolateral fixator, is a useful treatment modality in individuals with unstable hips.