Session II - Post-Traumatic Reconstruction

Outcome after Arthrolysis of the Hip for Severe Heterotopic Ossification and Ankylosis

Michael Skutek, MD; Stefan Hanning; Ulrich Bosch, MD; Christian Krettek, MD, FRACS; Department of Trauma Surgery, Hannover Medical School, Hannover, Germany

Purpose: The aim of this clinical study was to determine and evaluate the outcome after arthrolysis of the hip for severe heterotopic ossification (HO) and ankylosis.

Methods: Twenty-seven hips in 20 patients (5 women and 15 men with an average age of 43.25 ± 15.07 years) with HO Brooker grade 3 (N = 10 ) and 4 (N = 17) were included. All patients underwent open surgical arthrolysis between 1990 and 1997 at our institution. Arthrolysis was performed 21.3 ± 16.6 months (range, 6 to 60) after diagnosis of HO. Postoperatively, all patients received prophylaxis with Indomethacin for 6 weeks. Additionally, two patients were radiated. Outcome evaluation comprised clinical outcome and evaluation with use of the Merle d'Aubigne, Harris Hip, and the Lower Limb scores to cover all effects caused by this severe complication.

Results: The overall scores at the latest follow-up (5 ± 3 years) were 6.8 ± 3.5 (Merle-d'Aubigne), 60.7 ± 20.7 (Harris Hip), and 77.2 ± 20.7 (Lower-Limb). There was a mean correlation between the interval (diagnosis to time of operation) and the score results (Merle-d'Aubigne and Harris-Hip Score) of r = ­0.54, respectively. The mean hip flexion was 55.5° ± 35.1° and correlated negatively with the interval (r = ­0.66).

Discussion/Conclusions: There were satisfying results after operative arthrolysis for heterotopic ossification and ankylosis. However, functional results deteriorated with an increasing interval (diagnosis to arthrolysis). After consideration of all contraindications, operative arthrolysis should be performed as early as possible after diagnosis of HO. The results of this study do not support the previous hypothesis that early arthrolysis results in recurrence of impaired hip function.