Predictors of surgical outcomes following anterior transposition of ulnar nerve for cubital tunnel syndrome: a systematic review.

PURPOSE: Although cubital tunnel syndrome is the second most common nerve entrapment neuropathy, few studies explore potential predictor(s) of surgical outcomes. The purpose of this systematic review was to determine which factors affect the postoperative outcome for patients who undertake anterior transposition of the ulnar nerve. METHODS: We included all studies reporting predictor(s) of clinical, electrophysiological study, or functional outcome after any anterior transposition of the ulnar nerve. We searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and CINAHL from 1980 to April 2011 and reference lists of articles. Two reviewers performed study selection, assessment of methodological quality, and data extraction independently of each other. RESULTS: We assessed 26 studies including 2 randomized controlled trials, 10 cohort studies, and 14 case series. Overall, the methodological quality of the studies ranged from low to moderate. Six aspects of prognosis were sufficiently studied for a narrative evidence synthesis on age, duration of symptom, severity of operative status, preoperative electrodiagnostic testing results, type of surgery, and work compensation status. Evidence was conflicting across studies in terms of both the direction and intensity of the impact of these 6 potential predictors on surgical outcomes. CONCLUSIONS: Because of conflicting results, we were unable to conclude which predictor(s) affect surgical outcomes after anterior transposition of the ulnar nerve. Surgeons who are aware of only a limited number of prognostic studies and their limited scope of evidence may not appreciate the extent of the inconsistency about whether factors commonly viewed as prognostic actually have a noteworthy impact on outcomes achieved. Such factors may be identified in the future with higher-quality studies, because limitations in the current research undoubtedly contribute to the controversies observed.