Review ArticlesHistopathology of Rotator Cuff TearsLongo, Umile Giuseppe MD, MSc*; Berton, Alessandra MD*; Khan, Wasim S. PhD†; Maffulli, Nicola MD, MS, PhD, FRCS(Orth)‡; Denaro, Vincenzo MD*Author Information *Department of Orthopaedic and Trauma Surgery, Campus Biomedico University, Via Alvaro del Portillo, Trigoria Rome, Italy †University College London Institute of Orthopaedic and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK ‡Centre for Sports and Exercise Medicine, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Mile End Hospital, London, UK The authors declare no conflict of interest. Reprints: Umile Giuseppe Longo, MD, MSc, Department of Orthopaedic and Trauma Surgery, Specialist in Trauma and Orthopaedic Surgeon, Campus Bio-Medico University, Via Alvaro del Portillo, 200, Rome 00128 Italy (e-mail: [email protected]). Sports Medicine and Arthroscopy Review: September 2011 - Volume 19 - Issue 3 - p 227-236 doi: 10.1097/JSA.0b013e318213bccb Buy Metrics Abstract The pathogenesis of rotator cuff tears is multifactorial. Tendon abnormalities of the rotator cuff include alteration of collagen fiber structure, tenocytes, cellularity, and vascularity. Ruptured tendons show marked collagen degeneration and disordered arrangement of collagen fibers. Fibroblast population decreases as the size of the tear in the rotator cuff increases. The larger fibroblast population seen in the smaller tears is also actively proliferating and is part of an active reparative process. Inflammatory cell infiltrate correlates inversely to rotator cuff tear size in the torn supraspinatus tendon samples, with larger tears showing a marked reduction in all cell types. As tear size increase, there is also a progressive decrease in the number of blood vessels. Whether rotator cuff tear heals spontaneously is an important pathologic and clinical question. Histologic changes indicative of repair and inflammation lead to consider biological options in addition to biomechanical treatment of the rotator cuff tears. © 2011 Lippincott Williams & Wilkins, Inc.