When thinking about injured body parts, bones and muscles often get all the attention. A different type of structure exists all over our body and is often the actual cause of our pain. This structure is a tendon. Tendons attaches our muscles to our bones and are absolutely key in allowing us to move as they transmit the force our muscles create onto our skeleton!
When tendons get injured however they are probably one of the hardest structures to treat. This is mainly due to a lack of understanding about how tendon’s adapt and respond to change.
As well as just transferring force from muscles to bones, tendons are actually able to store and release elastic energy. This function is especially important in athletic performance. Tendons (very large versions) are what allow a kangaroo to spring along so efficiently!
How to know if it is a tendon that you hurt?
Tendons adapt very slowly to new loads, so if you have developed pain associated with a recent increase (or new) activity, it is possible that your tendon rather than your muscles are the structure that is struggling with your new activities! To be sure that your tendon is what is at fault takes close questioning and assessment. Often tendon pain is one that seems to come back over and over again and I’m guessing quite a few of you have experienced this or at least know someone who has!
Patients often get frustrated in the process when it comes to returning to pain free activity, because your tendon injury either hasn’t been explained well enough, or the practitioner doesn't quite understand tendon pathology well enough to best assist you. I’m hoping today to bridge that understanding gap and give an insight into the treatment of tendinopathies.
Please Note! The next section is going to get a bit technical. If you have previously had or currently do have a tendon injury (or you are a health professional) this section is well worth reading. If you would like to skip the details and just see how to get things fixed… jump to the bottom!
Tendinopathy is a broad term that encompasses painful conditions occurring in and around tendons in response to overuse. The previous term tendinitis worked on a old paradigm that inflammation was involved in tendon injury however more recent studies show painful tendons are devoid of inflammatory cells. What that means is that dysfunction here doesn't follow normal inflammatory/histological processes that we may find with muscle or bony injury and has no clear end-point. Instead, the pathology involves complex and ongoing non-inflammatory alterations in the tendon matrix and cells. It is essential to understand this, as it underpins how we choose to treat and assess the injury.
Loading changes are the primary stimulus that appears to drive the tendon response towards pathology. Repetitive energy storage and release and excessive tendon compression appear to induce pathology.
Most tendinopathies in the body usually occur at what we call the enthesis - this is the point at which the tendon inserts onto the bone. The only exception to this is a mid-portion achilles tendinopathy. At the enthesis, there are two main factors which influence the amount of stress that happens at the tendon:
1) tensile load from the loading through collagen fibres of the tendon when there is muscle use and 2) compression load around a bony insertion point (as most insertions work around a bony pulley - e.g. heel bone of the achilles).
In mid-portion achilles tendinopathy - tensile load is the biggest factor leading to tendon pathology - mainly the stretch-shorten storage and release of energy (e.g. jumping).
Loading a tendon causes matrix and cell deformation, and depending on the type and amount of load, the cell responds by producing matrix proteins (mainly collagen). Exercise increases collagen production that may contribute to increased tensile strength of a tendon however, there appears to be a fine line between load that stimulates a positive tendon response and load that triggers a negative response. Due to this, tendons are SLOW TO ADAPT TO CHANGE!! This is critical to understand why tendon rehabilitation takes so long, and also why a sudden change in training can cause pain in the first place. Tendons take up to 3 days after a bout of loading to respond to that load. If we load it too quickly before that point, then we can easily send the tendon over the edge.
Researcher Physiotherapist Jill Cook and colleague Craig Purdam have done extensive research into tendon pathology and rehabilitation. Just google their names with ‘tendinopathy’ and you’ll find pages and pages of research on the topic by these two. After overload in a tendon they propose a three stage tendon pathology continuum:
1) reactive phase - this is an acutely overloaded tendon. At this early stage, the tendon can revert to normal if the overload is discontinued or there is sufficient time between loads for the tendon to recover.
2) disrepair phase - this is essential failed healing and results from ongoing load to a reactive tendon, causing structural disorganization of the internal tendon substances resulting in some separation of the collagen and reducing its loading capacity.
3) degenerative phase - progression to extreme changes to a disordered internal structure, cell death and little collagen. These patients will usually have times when are pain free and will continuously recur over and over again.
Figure 1 from Cook & Purdam (2009)
STOP NOW IF YOU SKIPPED THE GOOD BIT!
So what can we do if you come in to see us?
Firstly lots of questions will be asked to find out what increased loading has placed the tendon over the edge. We will also try and figure out whether it is more a compression or tensile loading issue in your case. This allows us to guide treatment and create conditions in which to create comfort and allow relative de-loading of the tendon. We also need to find out a bit about your previous history, current training loads, previous training loads etc, which allows us to ascertain whether there are other intrinsic factors at play they may need to be addressed concurrently. A good Physio will ask a lot of questions! So be patient with us, as this will assist us in helping you!
Now it is important to note that research has shown the gold standard treatment option to return to function is through exercise intervention. This will get you 80% of the improvement. Remember there is no inflammation component so things designed to treat inflammation may not be helpful.
Other treatments like massage, dry needling, joint mobilisation etc, are usually adjunctive and help the remaining 20% but only will not improve the condition alone! Specific exercises need to be done for this to get better. And the process will be slow! People managing this themselves usually progress too quickly or they go the complete other end by stopping all activity.
Now when we say de-load, this does not mean stop everything! Completely unloading a tendon is actually more detrimental than good because tensile load stimulates collagen production and directs its alignment as well as preserves muscular and whole body functional capacity. There are numerous ways to reduce load without stopping all activities. Relative rest means that the person may be able to continue playing or training if it is possible to reduce the amount of stretch-shortening happening or the total weekly training hours performed etc.
Your Physio will know what constitutes low, medium and high tendon loading activities and can guide you appropriately in this area. Because tendons do not like change and are slow to adapt we can only change one factor at a time in your rehabilitation progressions. Whilst it is easy to get frustrated with the slowness of these progressions, it is important to remember that when something takes some time to come on, it will also take some time to come right also.
Pathology on medical imaging is not related to pain! A lot of people have pathology on imaging but have never had pain - this is one reason some people can get tendon ruptures without ever getting pain in that tendon! Conversely some people have severe pain without any changes on imaging. Therefore imagining isn’t always of benefit for us a practitioner, but your history is likely to be more of benefit and will guide treatment more.
Research is still unclear on what causes pain in tendinopathy. Tendon pain can be easily changed without a change in tendon pathology. Physiotherapy techniques can improve your pain symptoms in one session which is great, however this is not enough time for a change in pathology to happen. Physiotherapy therefore can provide a great window of opportunity to use that time to increase the loading capacity of the tendon. For example, when leading up to an event, this may assist in providing pain free or at least pain reduced training sessions as guided by your Physiotherapist.
Another point to note is that patients usually don't present at the clinic until they are in the disrepair and degenerative stages. In these stages because tendon structural changes are already taking place we are unlikely to change the underlying pathology. We can still get your tendon loading capacity up and improve your pain and function, however in the early stages we have greater chance of returning the tendon back to normal structure.
So my advice would be if you have tendon pain - get in early! It may save you months of hard work and future pain episodes! Know the process will be slow, and that graduated exercise program is the only way to improve your tendon function.