Chronic Tendinopathy
Chronic tendinopathy is a characterized by increased cellularity and breakdown in the extracellular matrix (ground substance accumulation, disorganized collagen, neurovascular growth).
Once there is pathology that disrupts the collagen matrix then the tendon is less able to tolerate load leading to changes in the mechanical strength of the tendon as well as its capacity to withstand load.
The current model of tendon pathology is viewed as a continuum - reactive tendinopathy, tendon dysrepair (failed healing), and degenerative tendinopathy.
Adding or removing load is the primary stimulus that drives the tendon forward or back along the continuum. Reducing load may allow the tendon to return to a previous level of structure and capacity within the continuum.
Different stages of tendon injury allows us to have different treatment strategies based on the phase of injury.
What happens when you “push through pain”?
Pain inhibits the athlete using the elastic (energy storage and release) capacity of the tendon, thereby compromising function and performance.
Excessive training volume or intensity may compromise the elastic function of tendons lead to tendon overload.
Repeated training combined with too short resting periods can result in a net degradation of the matrix and lead to overuse injury.
Rehabilitation of Tendon Injuries
Factors in treatment of tendon injuries include; pain, pathology, and function.
Treatment can be optimized by tailoring interventions to the stage of pathology and targeting the primary driver of dysfunction and pain.
Restoring Tendon Function
Tendons are susceptible to different types of loads including; energy storage, compression, and friction. To restore tendon function you must have adequate strength, control, ability to store and release energy, and kinetic chain function.
Initial stages of rehabilitation begin reducing load by reducing training volume and intensity. Early addition of isometric/isotonic exercises help to reduce pain and cortical inhibition. It’s important from a brain perspective to reduce cortical inhibition in a painful tendon. Isometric/isotonic exercises are particularly effective before strength work because the loss of inhibition makes the brain more sensitive to strength work. Once this is achieved, then we shift the focus to strength of the affected muscle tendon unit.
Improve tissue capacity —> Improve performance
Tissue capacity refers to the ability of a tissue to tolerate the loads put on it. A tissue is at full capacity when the individual is able to perform functional movements at the volume and frequency required without exacerbating symptoms or causing tissue injury. This varies between tissues and varies between individuals. For example, if you want to go out and run, you have to have the ability to tolerate repetitive loads. If you want to run at a certain level, you have to have the tissue capacity to tolerate loads at that level.
Capacity is more tissue specific whereas function speaks to a tissue and its surrounding structures (ligaments, joints, etc). Putting this concept into practice, a rehabilitation program may start by working isometric then eccentric exercises then advance to more functional, sports-specific loading and plyometric exercises.
The idea is that simply strengthening a tendon doesn’t provide much load to the tendon but provides a good base for more functional activity. At the end of the progression the athlete should be able to use the elastic capacity of tendon and have regained function of the kinetic chain suitable for performance.
Ultrasound-guided tendon scraping
Repetitive or prolonged activities lead to degenerative breakdown of tendon fibers and formation of fibrotic tissue. These findings can be seen on ultrasound exam as swelling of the tendon, thickening of the tendon sheath, and altered tendon movement. Other findings include increased increased neovascularity, which is associated with chronic painful tendons.
Mechanical tendon scraping is an office-based procedure which can be used for certain cases of tendinopathy (most commonly in the Achilles and patella tendons). Tendon scraping is particularly helpful in cases where there are restrictions in tendon gliding movements that limit the ability to perform rehab exercises.
Ultrasound-guidance with Doppler is used to visualize the tendon and nearby structures. Using a local anesthetic and sterile saline; the infiltrative fat, blood vessels, and nerves are scraped away from the tendon to help restore normal tendon glide.
The treatment is performed outside the tendon, which allows for immediate weight-bearing and progressive increase in loading.
Platelet-Rich Plasma
When tendons fail to repair on their own and symptoms continue to limit activities despite 3-6 months of conservative management (activity modification, PT, etc..), platelet-rich plasma injections can be considered as a viable treatment option.
References:
Khan K, Cook J, Bonar F, Harcourt P, Astrom M. Histopathology of common tendinopathies. Sports Medicine. 1999.
Cook J, Purdam C. Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. BJSM. 2009.
Rio E, Kidgell D, Purdam C, Gaida J, Mosele GL, Pearce A, Cook J. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. BJSM. 2015.
Khan K, Scott A. Mechanotherapy: how physical therapists’ prescription of exercise promotes tissue repair. BJSM. 2009.
Rees J, Maffulli N, Cook J. Management of tendinopathy. AJSM. 2009.
Cook J, Purdam C. The challenge of managing tendinopathy in competing athletes. BJSM. 2004.
Alfredson H. Ultrasound and Doppler-guided mini-surgery to treat midportion Achilles tendinosis: results of a large material and a randomised study comparing two scraping techniques. BJSM. 2011.
Cook J, Rio E, Purdam C, Docking S. Revisiting the continuum model of tendon pathology: what is its merit in clinical practice and research? BJSM. 2016.