[Ulnar nerve disorders at the elbow. Etiologic approach. Apropos of 40 cases]

The authors analysed the medical records of 40 patients with isolated ulnar nerve entrapment at the elbow with a follow-up ranging between 7 months and 6 years. According to MacGowan's classification, there were 32.5% stage I, 25% stage II and 42.5% stage III. In 82.5% of cases, surgical decompression consisted of simple neurolysis by section of Osborne's arcade, while the other patients underwent transposition in the case of a local anatomical lesion (10%) or medial epicondylectomy (7.5%). The results in this series showed 50% very good, 15% good, 65% fairly good and 20% poor results, comparable to the results reported in other published series. The authors propose a classification into six groups which may have a prognostic significance, based on the mode of onset and the course of the paralysis: primary mononeuropathy (45% of cases in this series), compressions due to a local cause (10% of cases), postural compression (12.5% of cases), rapid-onset post-traumatic compression (10% of cases), sudden onset mononeuropathy (10% of cases) and mononeuropathy related to a systemic disease (10% of cases). The distribution according to MacGowan's classification was fairly homogeneous, but the postoperative results showed marked differences. A review of the literature showed that each author uses a particular technique and no other prognostic elements have been previously proposed.