Modern orthopedics is all about structure. However, there’s a big problem with this focus. Recent research shows that this model is seriously flawed. For example, it’s an urban myth that cartilage loss in the knee is associated with knee pain, and most orthopedic surgeons today replace knees based on this assumption. The problem with the assumption is that studies show the same type of cartilage loss in patients with no pain. What then is the culprit? Knee arthritis nerve pain.
Why Knee Replacement Is Usually a Bad Idea
Pain is typically the driving force behind the decision to get a knee replacement, and most orthopedic surgeons have it all wrong when it comes to the cause of your knee pain. How do we know this? Of course, there’s the research, but an even more direct indicator is that so many knee-replacement patients are still in pain after the procedure. Here are some studies:
- Chronic knee pain is the most common complaint following knee replacement.
- Pain rates worsen as time goes on—studies have followed out as far as four years following knee replacements.
- Knee pain could be due nerves traced to an issue in your back.
In addition to chronic pain, there are many risks and other problems associated with knee replacement. Only 1 in 20 patients with knee replacement are eventually able to function at normal activity levels. Younger knee-replacement patients (those age 55 and younger) typically experience more pain and wear out the artificial joint faster.
Allergies to the prosthesis can be an issue as well. Normal wear and tear can cause the knee-replacement device to shed metal particles, causing a buildup of ions in the blood. In fact, if you already have allergies to any metal, such those in jewelry, you could also be allergic to the metal in the artificial knee. Taking that a step further, if you have allergies to anything (e.g., pet dander, pollen, etc.), allergic reactions to the artificial knee are more likely. The new plastics used in these knee devices can also induce an allergic response.
If ongoing pain and these other risks aren’t enough, there’s much more:
- Spinal-fracture risk increases following knee replacement.
- Hip-fracture risk increases for up to 10 years following a knee replacement.
- Heart attack, stroke, and blood clots are a severe risk following a knee replacement.
As you can see, there are a lot of risks involved in a knee replacement, and the findings in this newest study suggest these surgeries are being performed based on a flawed orthopedic pain model.
The Phenomenon Known as Temporal Summation
I’ll discuss the new research in just a moment, but to understand this study, you need to know what temporal summation (aka wind-up and central sensitization) is. At the basic level, it occurs when the nervous system amplifies pain signals. This ramp up is a good thing when an injury is acute, or when it first occurs because it helps you keep weight off of the affected body part or not let anything touch the area as it heals. However, these amplified pain signals are a bad thing when the pain is chronic because it makes the affected area feel much more painful. In temporal summation, individual painful events get lumped together and magnified, or blown way out of proportion.
The New Study: Knee Arthritis Nerve Pain
For this new study, researchers induced pain in knee arthritis patients and found that their structure didn’t account for their pain levels. So what did? Their nerve hypersensitivity. Once again, this demonstrates that knee arthritis pain is more about the nerves than what the X-ray or MRI shows the knee structure. The study concluded that “the temporal summation of pain response… is not explicable by a specific time-dependent behaviour of stress and strain in the activated deep tissue and hence not due to changes in tissue biomechanics.”
Knowing that this study showed that knee arthritis pain is more about nerves and not about the mechanics of the knee, this likely explains why many times after the knee is amputated and a prosthesis is inserted (knee replacement), many patients still report significant knee pain. In fact, the most commonly reported pain number on the pain scale after a knee replacement is a whopping 5 out of 10.
The upshot? This new study showing knee arthritis pain due to nerves, as opposed to knee arthritis pain due to tissue mechanics, would likely come as a big surprise to your surgeon. It’s why many times we see that replacing the old knee with a new one doesn’t address the knee arthritis nerve pain, and if this radical surgery, associated with so many complications and risks, isn’t addressing the real cause of the pain, what’s the point?