[Cubital tunnel syndrome and heterotopic ossification. Eight case reports]

The occurrence of cubital tunnel syndrome during heterotopic ossification is infrequent. Entrapment of the nerve requires early decompression whereas definitive elbow release is often delayed to reduce the risk of recurrence of periarticular ossification. The pathophysiology and treatment of these two conditions are discussed.

The authors report a retrospective study of eight men (average age 37 years), all with previous head injury. The nerve entrapment was severe in two cases, moderate in four and mild in two. The elbow was ankylosed with a mean flexion deformity of 96 degrees (77 degrees-123 degrees). Management consisted of early decompression and neurolysis with anterior transposition of the ulnar nerve. In four cases elbow release was postponed until maturation of the ossification.

The neurolysis results were assessed according to the score of KLEIMAN modified by TEOH. They were excellent in two cases, good in five and bad in one.

Entrapment of the ulnar nerve in the context of heterotopic ossification seems related to compression and tension on the ulnar nerve. The compression may be due to prolonged pressure of the medial edge of the elbow on the bed of the nerve, or to a periarticular bony bridge and the initial inflammatory reaction of the heterotopic ossification. Ulnar nerve tension seems to be due to prolonged flexion of the elbow joint and to movements of the shoulder and the wrist, on either side of the ankyrozed elbow. Treatment should be by early decompression of the nerve and we recommend, in addition, anterior transposition to reduce the tension on the nerve. The elbow release can be combined with the neurolysis or delayed according to the state of activity of the heterotopic ossification.