Recurrent ulnar-nerve dislocation at the elbow.

Recurring luxation of the ulnar nerve at the elbow is not uncommon (16.2%), occurring about equally in young and old, male and female, athletes and non-athletes but the greater mobility is usually at the dominant arm. The probable cause of such dislocation is congenital laxity of supporting ligaments. Being more vulnerable to injury than normally-positioned nerves, however, complicating neuritis can does occur. Subluxating nerves which stop on the tip of the medial humeral epicondyle upon 90 degrees or more of flexion at the elbow are more subject to direct trauma than completely displaced neural structures which cross the epicondyle upon elbow flexion. The latter may develop friction neuritis which occurs most frequently in industrial workers and occasionally requires surgical transfer. Deep intramuscular implantation, with or without neurolysis, is definetely superior to subcutaneous placement of the affected nerve. In this report are described chemically-induced ulnar neuritis from cortisone injections about the medial humeral epicondyle; pressure ulnar neuritis in patients with enforced bed rest and from improper positioning on operating table with permanent neural deficit and the relationship of such hypermobile ulnar nerves to extension-flexion (whiplash) trauma to the neck. It is emphasized that most of these complications could have been avoided had the patient and his physician known that such anomalies were present. Of particular importance is the avoidance of pressure to the medial aspect of a flexed elbow in surgical patients under general anesthesia. The unrelated co-existence of intermittently-symptomatic hypermobile ulnar nerves and extension-flexion neck trauma may occur. Recognition of isolated unlar neuritis in these patients is definitely important from the diagnostic, treatment and medical-legal aspects of such cervical spine injuries.