Upper-Extremity Injuries Have the Poorest Return to Play and Most Time Lost in Professional Baseball: A Systematic Review of Injuries in Major League Baseball

To summarize the incidence of injuries occurring in professional baseball and compare player outcomes reported in the literature.We conducted a systematic review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines across 3 databases (PubMed, MEDLINE, Embase). Inclusion criteria were studies of injury incidences and/or injury outcomes on active Major League Baseball (MLB) athletes and studies published in the English language. Exclusion criteria were non-MLB players, case series and case report studies with a cohort of ≤3 players, and/or review articles.A total of 477 articles were identified from the initial search of 3 databases, with 105 studies meeting inclusion criteria. Among these articles, the most common injuries studied were elbow (38%), shoulder (14%), hip/groin (11%), hand/wrist (7%), head/face (7%), knee (7%), spine (5%), and foot/ankle (3%). Injuries with the greatest incidence included hand/wrist (150.3 per year), hamstring (7.8-73.5 per year), ulnar collateral ligament (UCL) tears (0.23-26.8 per year), gastrocnemius strains (24.2 per year), and concussions (3.6-20.5 per year). Lowest rates of return to play were seen following shoulder labral tears (40%-72.5%), rotator cuff tears (33.3%-87%), and UCL tears (51%-87.9%). The injuries leading to most time away from sport included elbow UCL tears (average 90.3 days treated nonoperatively to 622.8 days following revision reconstruction), shoulder labral tears (average 315-492 days), and anterior cruciate ligament (ACL) tears (average 156.2-417.5 days). Following ACL tears, rotator cuff tears, shoulder labral tears, and hip femoroacetabular impingement requiring arthroscopy, athletes had a significantly lower workloads compared with before injury upon return to play.Most published investigations focus on elbow injuries of the UCL, with variable return to play and mixed performance following surgery. UCL tears, shoulder labral tears, and ACL tears result in the most missed time. Upper-extremity injury such as shoulder labral tears, rotator cuff tears, and UCL tears had the poorest return to play rates. Workload was most affected following ACL reconstruction, rotator cuff repair, shoulder labral repair, and hip arthroscopy for femoroacetabular impingement.Level IV, systematic review of level II-IV studies.