Incidence and risk factors for musculoskeletal disorders of the elbow in baseball pitchers: a systematic review of the literature.

Objective To determine the incidence and risk factors of musculoskeletal disorders of the elbow in baseball pitchers. Design Systematic review. Data sources Medline, CINAHL, Cochrane, PubMed and SportDiscus from onset to July 7, 2018. Eligibility criteria Eligible studies included randomized controlled trials, cohort studies and case-control studies. Independent pairs of reviewers screened titles and abstracts for eligibility. Relevant articles were critically appraised for internal validity using the SIGN criteria. We included low risk of bias studies in our best evidence synthesis. Results We retrieved 4502 articles, 39 were critically appraised and nine had a low risk of bias. These were included in the evidence synthesis. The incidence of musculoskeletal disorders of the elbow ranges from 2.3% in adolescent pitchers to 40.6% in youth pitchers. Evidence suggests that pitch characteristics, inadequate rest, biomechanical and anthropometric factors may be risk factors of UCL tears. Summary/conclusion Baseball pitchers develop musculoskeletal disorders of the elbow. There is little high-quality evidence to understand the etiology. Preliminary evidence suggests the risk factors are multifactorial.PROSPERO Trial Registration Number: CRD42018092081.