Ulnar nerve compression at the elbow and heterotopic ossification: a report of five cases

Heterotopic ossification (HO) is common in head-injured patients. Ulnar nerve compression by HO at the elbow is rare. The purpose of this study was to establish a strategy for the management of ulnar nerve compression secondary to HO at the elbow. The authors report a retrospective study (2000-2008) of five cases of ulnar nerve compression at the elbow secondary to HO. All patients were male (mean age, 33 years). The HO was secondary to head injury (four cases) and severe burn (one case). According to the Dellon's classification, the ulnar nerve entrapment was severe in two cases and moderate in three. The elbow was ankylosed; the flexion deformity ranged from 60 degrees to 120 degrees. Only in one case was nerve decompression performed before HO maturation. In the other cases, elbow release and nerve decompression were done at the same time, when maturation of HO was achieved. Postoperative outcome assessment was based on the Kleiman and Bishop's score. At 4 years of follow-up, the neurolysis result was excellent in one case, good in three cases, and poor in one. It seems that HO is not the direct cause of ulnar nerve compression, but its impairment may be increased by the nerve tension and elbow fixation that it causes. When HO is mature, neurolysis can be combined with elbow release. However, when HO maturation is not achieved early neurolysis associated with anterior transposition should be done without elbow release.