Evidence of Nervous System Sensitization in Commonly Presenting and Persistent Painful Tendinopathies: A Systematic Review.

Melanie L Plinsinga, Michel S Brink, Bill Vicenzino, C Paul van Wilgen

Study Design Systematic review. Objectives Elucidate if there is sensitization of the nervous system in those with persistent rotator cuff (shoulder), lateral elbow, patellar, and Achilles tendinopathies. Background Tendinopathy can be difficult to treat and persistent intractable pain and dysfunction frequent. It is hypothesized that induction or maintenance of persistent pain in tendinopathy is at least in part based on changes in the nervous system. Methods Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were followed. Relevant articles were identified through a computerized search in Embase, PubMed, and Web of Science followed by a manual search of reference lists of retained articles. To be eligible, studies had to include quantitative sensory testing (QST) and evaluate individuals diagnosed with a persistent tendinopathy of the rotator cuff (shoulder), lateral elbow, patellar, or Achilles tendon. Methodological quality assessment was evaluated with the Newcastle-Ottawa Scale. Results In total, 16 full-text articles met the criteria for inclusion, of which the majority were case-control studies with heterogeneous methodological quality. No studies on Achilles tendinopathy were found. Mechanical algometry was the predominant QST used. Lowered pressure pain threshold was observed across different tendinopathies at the site of tendinopathy as well as at other sites, with the latter being suggestive of central sensitization. Conclusion Although more research on sensory abnormalities is warranted, it appears likely that there is an association between persistent tendon pain and sensitization of the nervous system. This evidence is primarily from studies of upper limb tendinopathy and caution should be exercised with inference to lower limb tendinopathy. J Orthop Sports Phys Ther, Epub 21 Sep 2015. doi:10.2519/jospt.2015.5895.