{"id":10800,"date":"2023-09-25T06:00:59","date_gmt":"2023-09-25T05:00:59","guid":{"rendered":"https:\/\/blogs.bmj.com\/bjsm\/?p=10800"},"modified":"2023-09-24T10:19:32","modified_gmt":"2023-09-24T09:19:32","slug":"the-msk-playbook-rotator-cuff-tears-and-tendinopathy","status":"publish","type":"post","link":"https:\/\/blogs.bmj.com\/bjsm\/2023\/09\/25\/the-msk-playbook-rotator-cuff-tears-and-tendinopathy\/","title":{"rendered":"The MSK playbook: Rotator cuff tears and tendinopathy."},"content":{"rendered":"

Is it an acute tear or wear & metabolic disrepair? A community MSK approach to managing the painful shoulder.<\/span><\/p>\n

Key words:\u00a0<\/b>#MSKplaybook #Mindthesofttissuegap #rotatorcuff #tendinopathy #SEM #rotatorcufftear #subacromialimpingment<\/span><\/p>\n

Introduction:<\/strong><\/p>\n

The rotator cuff muscles and tendons work as a dynamic structure to centralise the humeral head and aid movement, acting with the deltoid muscle and each other as force couples to keep the glenohumeral joint functioning and stable. The structural integrity and mechanical properties of the rotator cuff tendons are key to their function, with tears of the tendon and muscle degeneration being associated with pain and dysfunction. There is, however, an overlap between structural findings seen on both symptomatic (chronic tendon-related pain) and asymptomatic tendon tears. We discuss some of the current concepts around surgical repair, and whether the metabolic cascade of disrepair could explain chronic rotator cuff tendon pain associated with tears.\u00a0<\/span><\/p>\n

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Figure 1: The MSK Playbook on rotator cuff tears<\/span><\/i><\/p>\n

Tendons are not just a pulley, they are metabolically active and adaptable.\u00a0<\/span><\/p>\n

In the past, tendons were thought to be metabolically inert, but recent research has shown that although they have a relatively low metabolic rate (compared to muscle), they are capable of energy productions (glycolysis and mitochondrial respiration), with inflammatory signalling directly affecting tendon cell metabolism (<\/span>1,2)<\/span>. Changes to their structure at a histological and macroscopic levels has been studied extensively, and changes in one or both of these predisposes patients to tendon tears of rotator cuff related pain (see Figure 2(<\/span>3)<\/span>). It is key to remember, that unlike muscles, tendons lack a blood supply, evident through their white substance; tears are more likely in tendons than muscles.<\/span><\/p>\n

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Figure 2: Structural changes in tendinopathy (<\/span><\/i>4)<\/span><\/i><\/p>\n

Type 1 collagen is the most abundant connective tissue in tendons, but these can degenerate over time, or in response to injury or due to metabolic conditions (e.g. diabetes (<\/span>5)<\/span>). This can affect a tendon\u2019s properties leading to (<\/span>6)<\/span>:<\/span><\/p>\n