[Should we divide Osborn's ligament during epicondylectomy and in situ decompression of the ulnar nerve?].

INTRODUCTION: Two groups of patients with cubital tunnel syndrome were treated by neurolysis and medial epicondylectomy. In the first group, the operative procedure consisted solely of dividing Osborn's ligament and fascia but in the second group Osborn's ligament was reinserted after epicondylectomy to avoid dislocation of the nerve. The aim of this retrospective study was to compare the level of complete recovery after surgery and the frequency of dislocation of the nerve.

MATERIAL AND METHOD: Group one: Nineteen patients, with a mean age of 47.7 (15-65), and 52% female, with the dominant hand involved in 63% cases, were treated. According to Mac Gowan's criteria, 32% of the elbows were classified preoperatively as grade I, 52% as grade II and 16% as grade III. Sensory nerve conduction velocity across the elbow was less than 40 m/s in 40% of cases. The mean duration of the disease was longer than 3 years in 16% of cases. Group two: Twenty three patients, with a mean age of 54.1 (33-75), and 56% female, with the dominant hand involved in 56% cases, were treated. According to Mac Gowan's criteria, three 17% of the elbows were classified preoperatively as grade I, 47% as grade II and 34% as grade III. Sensory nerve conduction velocity across the elbow was less than 40 m/s in 60% of cases. The mean duration of the disease was longer than 3 years in 4% of cases. Both groups were evaluated by a surgeon not involved in the treatment by clinical examination and DASH scoring.

RESULTS: DASH scoring is correlated with functional recovery, grip strength and Mac Gowan preoperative scoring. In group one, (divided and reinserted ligament) with younger patients, half the incidence of Mac Gowan stage II and a shorter follow up, there were no dislocations, but less complete resolution of preoperative symptoms (68%/82%) and a higher DASH scoring (30.6/24.9). In group two (resected ligament), dislocation of the nerve was noted in 17% of cases. In both groups, pain at the epicondylectomy site was noted in 20% of cases. The chance of complete recovery was inversely related to the age (>50), and to the duration of the disease (>1 year).

DISCUSSION: Surgical treatment of ulnar nerve entrapment at the elbow remains controversial. None of the presently advocated procedures (simple decompression of the ulnar nerve, medial epicondylectomy or transposition of the ulnar nerve) has proven optimal regarding long-term results. In both groups in this study, neurolysis of ulnar nerve by section of Osborn's ligament and fascia together with medial epicondylectomy proved to be an effective surgical procedure for treating grade I to II ulnar neuropathy. Section of Osborn's ligament without its reattachment is followed by more cases of complete recovery as well as more dislocation of the nerve although the latter elicited no subjective complaints from the patients. DASH scoring is effective in evaluating the recovery.