Deltoid muscle tropism does not influence the outcome of arthroscopic rotator cuff repair

BACKGROUND: Several different factors have been identified as causes of failure of rotator cuff (RC) repair. However, no studies focused on the role of the deltoid muscle. The aim of this study was to investigate the role of the deltoid tropism in the outcomes of arthroscopic RC repair procedures. MATERIALS AND METHODS: Nine male (45 %) and 11 female (55 %) patients who underwent arthroscopic RC repair were included in the study. The mean age was 63.5 ± 8.1 years (range 50-74 years), and the follow-up averaged 1.9 ± 1.3 years (range 1-5 years) after surgery. Clinical outcomes were assessed using the modified University of California, Los Angeles (UCLA) shoulder rating scale, Wolfgang criteria shoulder score and Oxford shoulder score (OSS). Functional outcomes were evaluated considering active and passive range of motion of the shoulder and muscle strength. The deltoid tropism was measured pre-operatively and post-operatively using T2-weighted transverse MRI images. RESULTS: No statistically significant correlation was found between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the UCLA shoulder rating scale, Wolfgang shoulder score and OSS. At the same time, no statistically significant relationship was detected between the thickness of each portion of the deltoid muscle (vD, lD and dD) and the functional outcomes. CONCLUSIONS: The deltoid tropism does not influence the results of arthroscopic RC repair. Early RC repair may prevent the reduction in the tropism of the deltoid muscle. Nevertheless, further prospective randomized studies with larger samples are necessary to clarify the role of deltoid tropism in the outcomes of arthroscopic RC repair procedures.