To understand how tendinopathy occurs, we need to understand what tendon is and what it does. Tendon is a bunch of fibrous connective tissue that typically connects muscle fibres to bone. It is a non-contractile tissue similar to ligament. It functions like a spring to store and release energy. Tendinopathy occurs when tendon is overloaded. These loads come from the longitudinal load (spring load) and also compressive load such as pressure against bone or surrounding soft tissue.
The tendinopathy continuum theory
Tendinopathy does not happen without overloading:
Normal tendon -> overloaded -> reactive tendinopathy
Reactive tendinopathy -> continue to overload -> tendon disrepair (failed healing) -> degenerative tendinopathy
There are two main types of tendinopathy – reactive and degenerative, often it can appear as a combination – reactive on degenerative.
Reactive tendinopathy is a non-inflammatory proliferative response, whereas degenerative tendinopathy describes the stage of failure of tendon healing. A degenerated tendon has area of cell deaths and little collagen fibres and it is almost irreversible.
Why is tendon painful if it is not inflammatory?
It has been shown that tendon pain can actually occur regardless of the stage of the pathology. Even tendon with normal imagining findings can be painful. It has been found that pain is associated with multiple sources such as the presence of biochemical substance, nocioceptive substance, sensitized nerve and centrally mediated pain, etc. That explains why sometimes anti-inflammatory drugs alleviate pain but do not repair the tendon. Pain in a tendon should be considered based on the stage and level of pathology.
A good example is a proliferative tendon can be reactive and painful but yet still strong and has a good chance of reversing back to normal, if the load is modified appropriately (eg. Young athlete who overtrained); A very degenerated tendon can present with low pain levels but lack the ability to tolerate high load and at greater risk of rupture (eg. Detrained overweight older adult who wants to return to running).
To treat tendinopathy, we need to modified load to tendon:
Reactive tendinopathy (short term adaption) --> Modified load (appropriate rest or unloading) --> Normal tendon
Studies have shown adaptive changes of the tendon tissues in the first few days after overloading. It takes about twenty days for longer term adaption. Having appropriate rest and unloading will allow the tendon to pass the reactive phase, and provide the opportunity for true tendon adaptation to happen.
Reactive tendinopathy on degenerative tendinopathy --> Modified load --> Pain subside and intact tendon fibers remain strong.
There are multiple unloading strategies such as:
- Training alternate days or after three days
- Shortening the training duration
- Avoid excessive loading exercise
- Avoid compressive load (eg. stretching)
In terms of treatment using exercise, in the past, eccentric exercises such as the Alfredson’s protocol (heel drop 180x per day) was considered one of the best exercises rehabilitation for Achilles tendinopathy. It has good evidence in improving tendon strength and reduction of pain. However, the time required to improve can lengthy (3 months to 5 years+) and it can be painful to complete. This can be particularly problematic for sports players during the sports season to adhere to the exercises. Recent research has shown successful immediate pain reduction exercises using isometric exercises for up to at least 45 minutes (eg. 5 sets 45 second hold with 2 minutes rest between set at 70% maximal voluntary contraction).
There are many alternative treatment options that appear to be beneficial, but they do not consistently show superior results than placebo treatment, or compare to exercise treatment. These treatments include friction massage, shock wave therapy, ultrasound, prolotherapy, sclerosing therapy, nitric oxide patches and surgery etc. The consensus from recent researches for tendinopathy management remain focus on load modification, and using isometric and eccentric exercises with appropriate load for symptoms management and tendon strengthening, and progress to sports specific task training.
If you have any questions regarding your chronic Achilles or other tendon injuries, feel free to give us a call. Here at Thornleigh Performance Physiotherapy, we can give you an accurate diagnosis and treatment, as well as advice on the best course of action for your condition to get you back in action sooner than you could’ve imagined. We have an expertise in musculoskeletal physiotherapy and are conveniently located near Beecroft, Cherrybrook, Hornsby, Normanhurst, Pennant Hills, Wahroonga, Westleigh, West Pennant Hills, and West Pymble. So give us a call on (02) 8411 2050 to get started on a journey to a better you.
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