What You Should Know About Tendon Pain

Tendinopathy is a common condition in our population. Tendinopathy is a broad term used to describe painful tendons. The most common tendons to become painful are the Achilles, patellar, supraspinatus, and forearm extensor tendons (tennis elbow), although any tendon can be painful. This blog post will cover the pathology of tendon pain and some strategies to help build a stronger tendon while decreasing the pain. 

The pathology of tendinopathy has gone through a lot of changes over the previous few decades. Tendon pain was previously thought to have been caused by inflammation, which lead to the term tendinitis. Since inflammation was thought to be the driver of pain, anti-inflammatories (NSAIDs, ibuprofen, cortisone injections, etc) were the primary treatment choice. These treatments usually demonstrated mediocre short term benefits, but would often have a high re-injury rate. 

Further research on tendon pain revealed that inflammation was not present in painful tendons, but instead degeneration was the cause of pain. This was called tendinosis. This lead to treatments designed to stimulate tendon growth, such a platelet rich plasma (PRP) and prolotherapy. Research on the effectiveness of these treatments is still ongoing, but early research is promising. 

The current theory for tendinopathy is the continuum model proposed by Jill Cook and Craig Purdam. The continuum model states that tendinopathy is actually a spectrum from normal tendon to degenerative tendon. Tendinopathy is proposed to go through three stages: (1) reactive tendinopathy, (2) tendon dysrepair, and (3) degenerative tendinopathy. 

The first stage of tendinopathy is the reactive stage. In this stage, the tendon cells are stimulated to increase production. This results in an increase in cross-sectional area, decreasing the force per unit on the tendon. Decreasing the force per unit on the tendon is a short term strategy to decrease the demands on the tendon until it can adapt to the higher load. Normally tendons adapt to higher loads by increasing their stiffness rather than increasing their cross-sectional area. 

Tendon dysrepair is the second stage of tendinopathy. With the continued increase in cell and protein production, there is an accumulation of fluid in the tendon. This causes separation between the collagen fibers leading to disorganization in the tendon. This stage marks the transition from normal tendon to the breakdown of tendon, representing a failed healing response. 

The final stage of tendinopathy is the degenerative stage. Here there is cell apoptosis, which means cell death. In this stage, there is extensive disorganization in the tendon and blood vessels begin to infiltrate the tendon (which has been suggested as a possible cause of pain). Usually tendon degeneration represents prolonged overuse of the tendon. 

An important note about tendinopathy is that pain can occur in any of the three stages or not at all. It depends on whether the brain determines if what is going on in the tendon is threatening or not. As an example, it has been reported that some Achilles tendon ruptures had marked degeneration on diagnostic ultrasound, but were asymptomatic until the injury. So keep in mind that pain can be an unreliable tool for measuring tendon health. 

Now that we have a basic understanding of tendinopathy, let’s dive into how to treat it. For simplicity, let’s divide tendinopathy into two parts: reactive/early tendon dysrepair and late tendon dysrepair/degenerative. 

In reactive/early tendon dysrepair, load management is the most important factor. With prolonged overuse, the tendon cells are continually stimulated to build more tendon without a chance to remodel, driving the pathology to the degenerative stage. So decreasing the amount of force placed on the tendon will allow the tendon to properly adapt. Remember that there are multiple factors that contribute to the forces placed on the tendon. The duration, frequency, and intensity of activity will all place increased stress on the tendon, so a modification of all of these factors should be considered. 

Therapies that can help in this stage include joint mobilization, soft tissue work, and kinesiology tape. Alteration of the mechanics in a joint can lead to uneven distribution of forces through the body, which can result in increased force on a specific region. For example, a restricted ankle joint can place increased stress on the Achilles tendon. Soft tissue work (manual therapy or instrument assisted soft tissue therapy) can help improve fluid dynamics and reorganization of the collagen fibers. Kinesiology tape is also a good option for improving the fluid dynamics. Kinesiology tape has a lifting effect on the skin, which allows for easier movement of fluid under the skin. 

In late tendon dysrepair/degeneration, the aim for treatment is to stimulate tendon regeneration. In the beginning stages of treatment, isometric exercises (exercises that cause contraction of muscles but produce no joint movement) can be used to decrease pain and begin stimulating growth of the tendon. As movement becomes more tolerable, progression to concentric/eccentric exercises (exercises that cause joint movement) are recommended. For example, a wall sit would be an isometric exercise that would be useful in the treatment of patellar tendinopathy. Squatting would be the progression for a concentric/eccentric exercise (eccentric descending into the squat and concentric ascending). 

Soft tissue work can again aid in this stage of tendinopathy. Since there is extensive tendon disorganization, soft tissue therapy can help with reorganizing the tissue. For cases that fail to respond to conservative therapy, platelet rich plasma injections or prolotherapy can be used to stimulate growth of the tendon; however, it should be noted that medications nor injectables have demonstrated the ability to alter tissue properties. 

The treatment of tendinopathy has changed as our understanding of the pathology of tendons has increased. No longer is it adequate to just take a few ibuprofens and go back to your activity a few days later. An appropriate diagnosis will lead to more effective treatment strategies, which will decrease your time away from your activities and decrease your future risk of re-injury. As always, it is important to have your injury properly evaluated by a qualified professional.

References:
Cook JL, Purdam CR. Is Tendon Pathology a Continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. Br J Sports Med 2009; 43:409-416.

Cook JL, Purdah CR. The Challenge of Managing Tendinopathy in Competing Athletes. Br J Sports Med 2014; 48:506-509.
Scott A, Docking S, Vicenzino B, et al. Sports and Exercise-Related Tendinopathies; a review of selected topical issues by participants of the second International Scientific Tendinopathy Symposium (ISTS) Vancouver 2012. Br J Sports Med 2013; 47:536-544.