A classification method for neurogenic heterotopic ossification of the hip

Background: Existing classifications for heterotopic ossification (HO) do not include all HO types; nor do they consider the anatomy of the involved joint or the neurological injury. Therefore, we performed this study to propose and evaluate a classification according to the location of neurogenic HO and the neurological injury. Materials and methods: We studied the files of 24 patients/33 hips with brain or spinal cord injury and neurogenic HO of the hip treated with excision, indomethacin, and radiation therapy. We classified patients according to the Brooker classification scheme as well as ours. Four types of neurogenic HO were distinguished according to the anatomical location of HO: type 1, anterior; type 2, posterior; type 3, anteromedial; type 4, circumferential. Subtypes of each type were added based on the neurological injury: a, spinal cord; b, brain injury. Mean follow-up was 2.5 years (1-8 years). Results: The Brooker classification scheme was misleading - all hips were class III or IV, corresponding to ankylosis, even though only 14 hips had ankylosis. On the other hand, our classification was straightforward and easy to assign in all cases. It corresponded better to the location of the heterotopic bone, and allowed for preoperative planning of the appropriate surgical approach and evaluation of the prognosis; recurrence of neurogenic HO was significantly higher in patients with brain injury (subtype b), while blood loss was higher for patients with anteromedial (type 3) and circumferential (type 4) neurogenic HO. Conclusions: Our proposed classification may improve the management and evaluation of the prognosis for patients with neurogenic HO

Prevention of heterotopic ossification in high-risk patients with total hip arthroplasty: the experience of a combined therapeutic protocol

The combination of radiotherapy and indomethacin for the prevention of heterotopic ossification (HO) in high-risk patients undergoing total hip arthroplasty (THA) has not been reported. The aim of the present study was to present the experience of our department with this combined therapeutic protocol. Fifty-four patients who underwent THA received a single dose of 7 Gy of postoperative radiotherapy and 75 mg of indomethacin for 15 days. Patients were analyzed for clinical and radiographical evidence of HO development at 1 year postoperatively. The overall radiographical incidence of HO was 20.4% (95% CI 10.6–33.5%), while only 1 patient with clinically significant HO was seen. Patients with secondary arthritis due to congenital hip disease had a statistically significantly higher incidence of HO compared with those with osteoarthrosis. The clinical assessment with the Merle d’Aubigné score showed that patients with radiographic documentation of HO had a lower mean score compared with those with no evidence of HO. No treatment-related side effects were seen. Combined radiotherapy and indomethacin was effective in preventing heterotopic ossification after total hip arthroplasty. The evaluation of this efficacy compared with radiotherapy or NSAIDs alone should be the future target of larger randomized designs