title: Tendinopathy in sport.
abstract: BACKGROUND
  Tendinopathy is increasing in prevalence and accounts for a substantial part of all sports injuries and occupational disorders. Despite the magnitude of the disorder, high-quality scientific data on etiology and available treatments have been limited.
  
  
  METHODS
  The authors conducted a MEDLINE search on tendinopathy, or "tendonitis" or "tendinosis" or "epicondylitis" or "jumpers knee" from 1980 to 2011. The emphasis was placed on updates on epidemiology, etiology, and recent patient-oriented Level 1 literature.
  
  
  RESULTS
  Repetitive exposure in combination with recently discovered intrinsic factors, such as genetic variants of matrix proteins, and metabolic disorders is a risk factor for the development of tendinopathy. Recent findings demonstrate that tendinosis is characterized by a fibrotic, failed healing response associated with pathological vessel and sensory nerve ingrowth. This aberrant sensory nerve sprouting may partly explain increased pain signaling and partly, by release of neuronal mediators, contribute to the fibrotic alterations observed in tendinopathy. The initial nonoperative treatment should involve eccentric exercise, which should be the cornerstone (basis) of treatment of tendinopathy. Eccentric training combined with extracorporeal shockwave treatment has in some reports shown higher success rates compared to any therapies alone. Injection therapies (cortisone, sclerosing agents, blood products including platelet-rich plasma) may have short-term effects but have no proven long-term treatment effects or meta-analyses to support them. For epicondylitis, cortisone injections have demonstrated poorer long-time results than conservative physiotherapy. Today surgery is less indicated because of successful conservative therapies. New minioperative procedures that, via the endoscope, remove pathologic tissue or abnormal neoinnervation demonstrate promising results but need confirmation by Level 1 studies.
  
  
  CONCLUSIONS
  Novel targeted therapies are emerging, but multicenter trials are needed to confirm the results of exercise and mini-invasive treatments.
authors.affiliation: Section of Orthopedics and Sports Medicine, Department of Molecular Medicine and Surgery, Stockholm Sports Trauma Research Center, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Ackermann
authors.forename: Per
authors.initials: P
authors.lastname: Renström