The Journal of Bone and Joint Surgery December 1 2007, Volume 89, Issue 12 Michael Zlowodzki, MD1, Simon Chan, MD2, Mohit Bhandari, MD, MSc2, Loree Kalliainen, MD3 and Warren Schubert, MD3 Disclosure: In support of their research for or preparation of this work, one or more of the authors received, in any one year, outside funding or grants in excess of $10,000 from the Osteosynthesis and Trauma Care Foundation (OTCF) and of less than $10,000 from the Canadian Institute of Health Research (CIHR). Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated. Background: There is currently no consensus on the optimal operative treatment for cubital tunnel syndrome. The objective of this meta-analysis of randomized, controlled trials was to evaluate the efficacy of simple decompression compared with that of anterior transposition of the ulnar nerve in the treatment of this condition. Methods: Multiple databases were searched for randomized, controlled trials on the outcome of operative treatment of cubital tunnel syndrome in patients who had not previously sustained trauma or undergone a surgical procedure involving the elbow. Two reviewers abstracted baseline characteristics, clinical scores, and motor nerve-conduction velocities independently. Data were pooled across studies, standard mean differences in effect sizes weighted by study sample size were calculated, and heterogeneity across studies was assessed. Results: We identified four randomized, controlled trials comparing simple decompression with anterior ulnar nerve transposition (two submuscular and two subcutaneous). In three studies that included a total of 261 patients, a clinical scoring system was used as the primary clinical outcome. There were no significant differences between simple decompression and anterior transposition in terms of the clinical scores in those studies (standard mean difference in effect size = 0.04 [95% confidence interval = 0.36 to 0.28], p = 0.81). We did not find significant heterogeneity across these studies (I2 = 34.2%, p = 0.22). Two reports, on a total of 100 patients, presented postoperative motor nerve-conduction velocities; they showed no significant differences between the procedures (standard mean difference in effect size = 0.24 [95% confidence interval 0.15 to 0.63] in favor of simple decompression, p = 0.23; I2 = 0%, p = 0.9). Conclusions: The results of this meta-analysis suggest that there is no difference in motor nerve-conduction velocities or clinical outcome scores between simple decompression and ulnar nerve transposition for the treatment of ulnar nerve compression at the elbow in patients with no prior traumatic injuries or surgical procedures involving the affected elbow. Confidence intervals around the points of estimate were narrow, which probably exclude the possibility of clinically meaningful differences. These data suggest that simple decompression of the ulnar nerve is a reasonable alternative to anterior transposition for the surgical management of ulnar nerve compression at the elbow. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.