Understanding pain: why a “healed” injury can still hurt
As physiotherapists, we deal with pain — a lot.
Usually clients come to see us when pain is interfering with their daily lives. In some cases, the pain is very simple: “I sprained my ankle; it was sore for a few days and now it’s better.” However, with some clients, the pain is a little more complex. For instance, what began as an ordinary ankle sprain may still hurt months later, even though the doctor said it should be healed. Or maybe there’s pain that lasts for months without any apparent injury.
So how can pain come and go in such a seemingly random fashion?
Pathways of pain can come from many directions. Our understanding of pain has changed over the years. We used to think it was fairly straightforward. If we stubbed a toe or rolled an ankle, the pain fibres from that tissue sent a “pain signal” to a “pain centre” in our brains and — BAM — we felt pain. The more damage to the tissue, the bigger the pain fibre response, the more pain we felt.
We know now that pain is much more complex.
Our bodies actually have more than one pain centre, which we call a “pain matrix.” Collectively this matrix helps our brains interpret danger signals. Let’s return to the ankle sprain. In the beginning, an injured ankle sends signals to the brain, those signals go into the pain matrix and it considers: Is this a bad thing? Do I need to protect this ankle from more damage? If it decides “YES,” we feel pain. We limp. We need to sit down and rest it. This is common in acute injuries while tissues are healing. But what about that same ankle sprain three to six months later? It should be healed, so why does it still hurt?
The road to recovery
Many things can influence the brain as it decides whether these signals are threatening or not, especially if we have been in pain for longer than a few months. Factors that make the brain more sensitive to danger signals include increased stress, lack of sleep, prior traumatic experience, prior injuries, how we feel about pain and fear of not getting better, just to name a few. If we have many of these things occurring in our lives, our pain matrix can become more sensitive and decides that any signal from the ankle is dangerous and threatening; therefore, we can feel lots of pain, even if the injury has healed.
Does this mean my pain is “in my head” and isn’t real?
Pain comes from a complex interaction in our brains but this does not mean that pain you experience is not real. One of the most important things to take away from this new understanding of pain is that it’s not as simple as a signal from damaged tissue. Tissue injury is only a small part of the pain experience, and this understanding can help people begin to heal, increase their mobility and gain more control over their experience of pain. Fortunately, physiotherapists have many treatment options to help deal with pain. We can provide education, perform various techniques to help your joints and muscles move better, and provide exercises that will reduce pain and get you stronger.
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Sources: Physiopedia. Theories of Pain. Available from https://www.physio-pedia.com/Theories_of_Pain Accessed on Feb 10 2020 Physiotherapy Alberta. Understanding Pain. Available from: https://www.physiotherapyalberta.ca/public_and_patients/the_you_movement_blog/understanding_pain Accessed on Feb 10 2020