Injection Therapies for Musculoskeletal Conditions

In the first Matrix movie, there is a scene where Neo, played by Keanu Reeves, is first introduced into the matrix. He begins his training by sitting in a chair, has a long rod inserted into the back of his head and without any effort on his part, martial arts programs are downloaded into him. When he awakens, he finds himself fully proficient at the fighting arts and he very nearly defeats his mentor, Morpheus. In other words, he is able to bypass several life times worth of training to become proficient at hundreds of martial arts with just a click of a few buttons. It’s brilliant. Can you imagine if this applies to everything in life? Want to learn Spanish? Click.  Hola! Want to become a concert pianist? Click.  Beethoven Symphony Number 9 anyone?  All with a simple click of a few buttons while sitting in your arm chair.

Movies like the Matrix appeal to many of us because we all have this wish that we can achieve perfect outcomes but without having to endure the process. We want something for nothing. I would love to run like Mo Farah and ski like Alex Harvey. In fact, I would be happy to just be able to run 10km in under 40 minutes. However, training for this goal takes a back seat to work and family and my goal remains elusive. In life, there are no short cuts to achieving significant goals. Anything else is science fiction.

This blog is about the role of interventional procedures, or injection therapies, in the management of musculoskeletal conditions. These therapies can be broadly divided into 2 categories: anti-inflammatory and pro-inflammatory.

A) Anti-Inflammatory
1. Corticosteroid Injections: Cortisone injections are injected into joint spaces for their anti-inflammatory effects to provide quick relief of pain and inflammation.  Some patients experience excellent relief for months after one injection while others experience no relief at all. The reasons for the varied outcomes are complex. It greatly depends on an accurate diagnosis, the accuracy of the injection, the resiliency and ability of the injected joint or tissue to heal, and whether the painful site was the actual cause of the problem or whether it was merely a symptom of another cause. Its downside is that its effects are often short-lived and repeat injections into the same area unfortunately, has catabolic effects on soft tissue and cartilage cells. In fact, the practise of injecting cortisone into tendons now has rightfully reduced due to the high risk of tendon weakening and rupture. Currently, there is no consensus as to “how much is too much.”  Conservative physicians will often try 1 injection first and the patient is then re-assessed within 3 months to determine if the procedure was successful. The decision then on whether to repeat the procedure depends on a risk/benefit decision making.

2.  Lidocaine Injections: Lidocaine is short-acting anesthetic injected locally to joints, soft tissues or nerves. It is often used to confirm pain generators to establish a diagnosis (ie. whether the specific tissue or joint is indeed the symptom-generator).

B) Pro-Inflammatory injections: This group of injection therapies attempts to restore the normal functioning of tissues. Though commonly administered, how it does so remains poorly understood. The current understanding is that by injecting an irritant into a tissue, this will cause a momentary breakdown in order to trigger the body to respond by initiating a new cycle of healing. It kick-starts a new inflammatory process so that the body can proceed through the stages of tissue healing again, with the hopes that the tissue will rebuild itself to a more natural state. There are 3 types of these injections:
1. Prolotherapy involves the injection of dextrose or P2G (phenol/glycerin/dextrose).

2. Platelet rich plasma (PRP) involves collecting blood from your arm, spinning the blood in a centrifuge, to separate the platelet cells so that it can be re-injected into the joint or soft tissue injury. Although the mechanisms by which the tissue healing occurs is still under study, there is emerging evidence which do show that PRP, like Prolotherapy can be useful adjuncts to treat conditions like joint osteoarthritis, muscle tears and tendinopathies where conservative management has failed.

3. Autologous blood injections: Just like PRP, however, there is no separation via centrifuge. A patient’s blood is withdrawn and then re-injected in its entirety into the joint or soft tissue injury.

The success and failure of interventional procedures depend on many factors: a correct diagnosis, accuracy in determining pain generators, an understanding of the reasons for the pain generators, a conservative effort to address those reasons, a collaborative treatment team to facilitate communication and a patient who is invested in the process. Patient outcomes in multidisciplinary and collaborative practice is far more effective than each discipline in separation. Interventional procedures can be a powerful modality in the management of complex conditions. However, injections performed alone without the hard work of rehabilitation is seldom successful and yet that is how it is most often administered and how most clinical trials are routinely performed.   It’s the Matrix effect: osteoarthritis and muscle/tendon tears that have little strength and integrity do not magically become stronger or cured with the patient sitting in an arm chair after a needle is inserted into them. Injection therapies are not science fiction. They are simply another modality that is part of an overall rehab process which takes time, patience, sacrifice and hard work. Nothing of true significance in life is ever achieved without effort. The expectation otherwise will only lead to disappointment and the abandonment of a modality that was never meant to cure by itself in the first place.

If you are considering injection therapies, begin with physiotherapy treatments first with a physiotherapist who has knowledge of and experience with the procedure. If the injection therapy is necessary, ensure you continue to work with your physiotherapist after the injections. Remember:  injections are only a small part of your overall rehab program.  

Submitted by Albert and Karen Chan

Acknowledgment: We would like to thank Rob Holmes for his contribution to this article. Rob is a physiotherapist in Calgary and works at Evidence Sport and Spine.

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