Tendinopathy: Part 1 — What is a Tendon Injury?
TL;DR
Have you ever woken up and felt a horrible ache in your patellar or Achilles tendon — usually after doing a ton of work the day before? How about pain at the sole of your foot in the morning with your first few steps? If the answer is yes, you may have a tendinous injury!
Well, buckle up… because this is a hefty topic! At first, I didn’t realize just how dense and inconclusive the literature is surrounding these types of injuries — which might be a good explanation as to why clinically tendinous injuries are so tricky to treat.
Tendinopathy (tendon-based injuries) can present in two ways. The first is acute tendonitis, which usually includes red-hot sensations, swelling and pain. The second is chronic tendinosis, which has no inflammation but consists of a dull ache with the potential for flare-ups (nagging tendon pain).
The literature points to five factors that can influence tendon pathology: load, movement patterns, recovery, metabolism, and genetics. I will focus on tendon loading and movement patterns.
Having tendinopathy can feel akin to the world ending — every step or movement with that limb is painful. You get tossed from your routine, and maybe worst of all, you wake up and immediately feel discomfort. The sh*t part about tendinopathy is that while rest tends to make the boo-boo feel better, an unloaded tendon will only get worse.
This is where we play my favourite game of “How much can we do until we flare up?”. As annoying as this sounds (and is), flare-ups are informative from a therapeutic point of view as they can establish a tolerability threshold.
The pathogenesis of tendinopathies is a fairly muddy topic. In general, we understand that a damaged and painful tendon is one that is experiencing a tendinopathy (itis or osis). The predominant theory is that tendons are predisposed to tendinopathy if they are thin and stiff (which makes them brittle). This change to tendon elasticity may predispose them to micro-traumas that, over time, without adequate recovery, may result in degeneration and symptoms.
Part of tendon pathology is a stiffening of the tendon, a protective mechanism that shields the compromised area of the tendon. This stiffening will result in two issues: disproportionately low symptoms at below-threshold loads and additional spring at the start of an activity/movement.
The first issue is something I explain to every athlete I work with. Just because you have little to no symptoms while navigating your low-impact daily life (haha this sounds like a roast) does not mean that you are ready to get cooking on the court, field, road, or trails. We do know that tendon loading does not follow a linear path, meaning running is exponentially more taxing on the tendon than walking is.
The second issue is of maddening potential — you go out for a run, your tendon is proper stiff and thus bouncy. You are flying… until maybe 10–15 minutes into the run. There is some relaxation of that stiffened tendinous tissue, and then we are back to loading that degenerated part of the tendon.
From a rehabilitation perspective, symptomatic flare-ups are informative and, in my mind, necessary. Flare-ups can help establish where the threshold for the tendon is — this can be from a load, volume or intensity view. Furthermore, we can begin to establish how modifiable factors such as diet and hormones can impact how the symptoms present.
Alcohol and poor dietary conditions can change the systemic inflammatory profile, potentially creating an environment that, at the very least, increases the sensitivity of soft tissue such as the tendon. Hormones, particularly in females, can change the stiffness of soft tissue and the production of collagen in the body. Therefore, the same adequate load to achieve adaptation on day one post-menstrual cycle may cause a symptomatic flare-up on day 20 post-menstrual cycle.
I think that understanding why a flare-up may have occurred is very powerful for a patient. Being able to anticipate when an action may lead to additional symptoms or preemptively modify loading to mitigate the risk of a flare-up might help to reduce the mental catastrophization that occurs with chronic tendinopathies.
Tendinopathies — Part 1 — What in Tarnation?
In the theme of spooky season, I decided to write about one of the spookiest of chronic musculoskeletal complaints: tendon pain. (I know what you’re thinking, “This story was published in November”). Well, sike! November turned into December very quickly. “December is not that spooky.” Well, grab yourself a candle, dim the lights and dust off the Ouija board because we need to set the ambiance for this blog.
Tendon pain can be a nightmare (ooky spooky, of course) for people. Tendon pain can be felt as a deep discomfort in a fairly inert tissue. Tendinopathy can present acutely as very inflamed and painful or chronically as a dull ache, which has the potential to flare into something more akin to the acute phase (swollen and painful).
People get trapped in this horror-iffic cycle of pain, partial recovery and then re-aggravation. In most cases, the underlying tissue issue has never been resolved, and the person is using symptom resolution as a guide to returning to full activity.
At this point, we can queue the theatrics — patients plead with their practitioners, their spirituality, and even the poor employee at the boutique running shoe store who only wants to correct pronation — “Why me?!?!” they ask.
This can be a tricky little question to answer, but in short, it’s multifactorial. My hope is that by the end of this blog, you will have more confidence in the management plan for your condition and less reliance on retail employees.
As a performance-based practitioner, I hate telling people not to move. Imagine you run 40km a week, and some stupid idiot says, “Yeah, you’re probably going to want to stop that”. The person has no fracture, strain, or other traumatic soft tissue tear. Their only issue is that after their run, they have tendon pain.
I mean, sure, stop running! The tendon pain will no longer hurt after runs, but eventually, it may start hurting after walks (current literature illustrates a modification in load, not cessation — silly goose). I’m not out here trying to fearmonger, but the reality with a tendon is that a strong tendon is a loaded tendon.
I’ll get more into what exactly is happening to the tendon, but from my perspective, it’s a wee bit silly not to address the tendon and make it more resilient to the activity the person wants to do while they continue to do it (in some capacity).
What is a tendinopathy?
Tendinopathies are, as their name suggests, tendinous injuries. We have two categories of common tendinopathies seen in the clinic:
1. Acute tendonitis — this is when your tendon is hot, red, and severely painful to load.
2. Chronic tendinopathy or tendinosis — this is where we see the most tendinous degeneration.
You may learn that this person had tendonitis previously, and their tendon was never the same after. From a tissue perspective, what the heck is going on? Well, acute tendonitis is the presence of tendon damage with inflammation. Tendinosis is tendon damage and pain without inflammation. The current theory around tendinosis is that it results from cumulative microtrauma(1,2).
This is where I’m at:
A great way to break down the pathogenesis or the cause of tendinopathies and, ultimately, the treatment is to subdivide the factors that contribute to tendon inflammation and degeneration (and, conversely, their healing and strengthening).
The literature consistently discusses five factors: load, recovery, movement patterns, metabolism, and genetics. This is a good time to mention tendinopathies are a pain in the ass. The common characteristic with many tendinopathy patients is what I like to call the cycle of madness (modness if you prefer the British grime vernacular). They’re mod/mad for a few reasons.
The first is that the length of time it takes to properly rehab a tendon is frustrating — up to a year! The next is the classic, “My sh*t feels pretty good right now. I’m going to do the thing that initially set off my injury at a pre-injury intensity”. The truth of the matter is that no injury has a linear recovery curve; there will be flare-ups, and this is especially true for tendons.
We will get into loading and movement patterns next week!
With Love,
Austin
Up next:
Part 2: Tendon Loading & Movement Patterns
Canosa-Carro, L., Bravo-Aguilar, M., Abuín-Porras, V., Almazán-Polo, J., García-Pérez-de-Sevilla, G., Rodríguez-Costa, I., López-López, D., Navarro-Flores, E., & Romero-Morales, C. (2022). Current understanding of the diagnosis and management of the tendinopathy: An update from the lab to the clinical practice. Disease-a-Month, 68(10), 101314. https://doi.org/10.1016/j.disamonth.2021.101314
Docking, S. I., & Cook, J. (2019). How do tendons adapt? Going beyond tissue responses to understand positive adaptation and pathology development: A narrative review. Journal of musculoskeletal & neuronal interactions, 19(3), 300–310.
