Evaluation of rotator cuff abduction moment arms for superior capsular reconstruction and reverse total shoulder arthroplasty.

PURPOSE: The rotator cuff (RC) muscles contribute to dynamic stability and rotational actions of the glenohumeral joint. Moment arm can be used to demonstrate the potential work a muscle contributes to a musculoskeletal joint rotation. This study aimed to understand the moment arm contributions of the RC muscles and explore changes following a complete supraspinatus tear treated with either superior capsular reconstruction (SCR) or reverse total shoulder arthroplasty (rTSA). METHODS: Five fresh-frozen cadaveric specimens were prepared and mounted in an apparatus where each intact RC muscle was held in tension with a line of action toward its origin on the scapula. Mean moment arms for each muscle were determined experimentally based on Optotrak data collected during cadaveric shoulder arm abduction. RESULTS: Using ANOVA testing, our analysis demonstrated significant differences (p < 0.001) in infraspinatus and teres minor moment arms after rTSA compared to the intact shoulder model. After SCR, significant differences (p < 0.001) were seen in teres minor, with these differences being statistically similar to the changes seen in teres minor after rTSA. Subscapularis showed no significant difference in moment arm values between the models (p = 0.148). CONCLUSION: Our results illustrate that mean moment arms were preserved in the RC muscles after complete supraspinatus tear. This study also shows evidence that subscapularis function may be maintained after SCR or rTSA. After SCR, infraspinatus may maintain similar abduction ability compared to the anatomical shoulder, while teres minor ability may increase. Infraspinatus may have decreased abduction ability after rTSA while teres minor may have increased ability.

Top 50 cited journal articles on overhead throwing athletes: a bibliographic analysis.

BACKGROUND: The frequency of citations for a journal article is a reflection of its academic impact. The purpose of this study was to identify and characterize the top 50 cited journal articles related to overhead throwing athletes in the published literature. METHODS: The Web of Science database was searched on January 18, 2016, using the terms "throwing athlete," "baseball," and "pitcher" to identify the top 50 cited articles related to overhead throwing athletes using the all-database function. The type of study, country of origin, publishing journal, and year published were reviewed for each article. RESULTS: The top 50 articles identified were cited between 95 and 471 times and were published in 13 journals between 1969 and 2011. Most of the articles were small case series or nonsystematic literature reviews. The shoulder was the most common body region studied in the top 50 articles (33 of 50 [66%]). Among original studies (n = 43), there was a good representation of surgical management of shoulder and elbow pathology in overhead athletes (9 of 43 [20.9%]); however, most of the articles reported on shoulder and elbow kinematics (19 of 43 [44.2%]) and pathoanatomy (15 of 43 [34.9%]). CONCLUSION: The greater prevalence of nonsurgical articles may reflect a continued effort to better understand the different pathologies specific to overhead throwing athletes. An understanding of the variable content and quality of frequently cited articles on overhead throwing athletes may serve as a stepping stone for future studies to advance the diagnosis and management of complex elbow and shoulder injuries in these high functional individuals.