Are inflammatory cells increased in painful human tendinopathy? A systematic review
Dean BJF, Gettings P, Dakin SG, & Carr AJ. Br J Sports Med. Published Online First: September 2015; doi: 10.1136/bjsports-2015-094754.
Take Home Message: Tendon-related issues seem to have increased inflammation, while torn tendons have significantly lower inflammation than tendon-related conditions in intact tendons.
Tendon-related injuries (e.g., tendinosis, tendonitis, tendinopathy) cause pain and limit function. However, questions remain as to whether or not they are inflammatory in nature. This is an important question since it could influence our treatment strategies. Therefore, the authors of this systematic review aimed to determine if inflammatory cells were increased in tendinopathy as well as to see the relationship between inflammatory cells and symptoms. The authors conducted a literature search of Medline and found 5 studies that compared inflammatory cell counts in tendon tissue from participants with tendinopathy and to healthy controls. Among the 5 articles, 3 included the rotator cuff, 1 included the Achilles tendon, and the last one evaluated the patellar tendon. The studies ranged from 6 to 10 (on a 10 point scale) for study quality as assessed by the authors. The included studies demonstrated that there tendons with tendinopathy had more inflammatory cells (for example, macrophages and mast cells) compared with healthy tissue, yet only 3 of the studies included statistical analyses of the quantitative results. The authors also reported that intact tendons with tendinopathy had less inflammatory cells in 2 studies compared with torn tendons. Based on 1 study, there was no relationship between inflammatory cells and symptoms.
This review could be very informative when selecting treatments for patients with tendinopathy because the authors concluded that there is an inflammatory components to tendinopathy. They also noted that the evidence supports the presence of chronic inflammation but not acute inflammation. Therapies, such as anti-inflammatory treatments, may help individuals suffering with tendinopathy. Future studies should investigate the effects of anti-inflammatory therapies within this population. However, the generalizability of this review is concerning since there is some debate amongst sports medicine professionals as to the cause of tendon-related conditions, such as tendinosis being degenerative or tendonitis being inflammatory. This review included each of these conditions as well as the overarching tendinopathy. The possible heterogeneity of tendinopathies may indicate that inflammatory cell counts could be different based on the nature of the condition, ultimately influencing the effectiveness of the treatment. An earlier post on SMR highlighted a study that showed early tendinitis may be inflammatory, but that this is not often seen in chronic tendinitis. It is interesting to see that torn tendons have lower inflammatory counts than tendinopathic tendons, but the question remains as to whether the inflammation lowering occurred before or after the tear itself. Ultimately, this highlights the need for more research in this area, but as clinicians anti-inflammatory therapies may be an option when treating patients with tendinopathies.
Questions for Discussion: Are there any treatments that you use for tendon-related pathologies? Are there any clinical findings that you use to differentiate between specific tendinopathies (tendinosis vs. tendinitis)?
Written by: Nicole Cattano
Reviewed by: Jeffrey Driban