Patients always want to know when to have a knee replacement (or hip replacement for that matter). Should they get this invasive surgery early or wait? You can find articles sponsored by the companies that make these devices that suggest getting it done early is better, but the concern there is whether the company is trying to boost sales or whether this is based on some research. There is research that provides some clarity to this question, and the answer is the opposite of what you would think.
Before I address the question of when to have a knee or hip replacement, let’s review many of the issues I’ve covered over the years regarding these surgeries.
The Issues with Knee or Hip Replacement
There are risks that need to be seriously considered before making the decision about whether or when to have a knee replacement or a hip replacement. You can’t amputate a joint and not cause severe trauma in the process. It’s a complex and highly invasive surgery. Severe complications can ensue, such as blood clots, heart attacks, and strokes. Besides the trauma to the joint, bone, blood vessels, and bone marrow space, heart attacks can even be triggered from the stress of the surgery.
The most common complaint that patients have following a knee replacement is continuing pain, which is concerning since most patients undergo this drastic surgery with the hopes of eliminating their pain. More troubling is there are some studies showing rising pain rates in the years following knee replacements. Considering your pain in your knee may be generated from a problem in your lower back, this could explain the progressively worsening pain despite the knee replacement. If the pain isn’t really coming from the knee, certainly a knee replacement isn’t going to fix it. In addition, very few knee replacement patients actually achieve normal activity levels following their surgery.
Hip replacement risks are also numerous. Hip replacement changes the biomechanics of the leg that can disrupt hip and knee alignment. The wear debris from the metals in the artificial hip joint can damage chromosomes, leading to genetic issues. Metal-on-metal hip implants can also cause chromium or cobalt toxicity, and this can lead to more pain. Research has also shown an increased risk, by double, of heart failure in men who’ve received metal-on-metal hip implants.
The artificial joints that replace knees and hips are typically made of metal, plastic, ceramic, or even a combination of these materials. These devices can shed particles as the joint moves, and metal ions from the artificial joint can enter the bloodstream. In addition, patients who have metal allergies to things such as jewelry are likely to have allergies to the metals used in these knee replacement devices. Allergies to the device can cause failure of the joint replacement, chronic pain, or revision surgery (replacement of the artificial joint) earlier than expected. The allergy risks of knee replacement may also include patients who suffer from any kind of allergy, not just metals. as the patient’s immune system is accustomed to trying to fight off foreign bodies (in this case the artificial joint).
Should You Wait or Get Your Joint Done Early?
A large study was published on this topic way back in 2012. It looked at the results of almost two thousand knee and hip replacement patients versus multiple variables, like age, sex, weight, starting arthritis severity, and preexisting fibromyalgia. Not surprisingly, if you had fibromyalgia (widespread pain), there was a 3–5 times greater chance of having more knee or hip pain after a replacement surgery. However, what was most interesting was that the patients with less-severe arthritis had more ongoing pain with knee or hip replacement than those patients with more-severe arthritis. Also, being younger at the time of surgery also was associated with more pain after the surgery.
These findings are the opposite of what I see being recommended right now. I see buses in my area plastered with billboards suggesting that younger and more-active people (the ones with less arthritis compared to a 70-year-old) get their joints replaced to remain active. I see newspaper ads that say the same thing and the web is littered with similar advertisements. Why? Joint replacement has become huge business for both doctors and hospitals. In addition, the push toward getting people to replace their joints in their 40s and 50s is based on expanding the market size for manufacturers of these devices as there are only so many 70-year-olds who need a joint replacement.
The upshot? The answer to the when to have a knee replacement, now-or-wait question, based on the published research, is “wait.” Let the joint get to the point where it’s more degenerated. In addition, the new trend of pushing younger people to get joints replaced seems ill-advised not only based on this study showing higher pain after the surgery but also on the simple idea that more-active people will wear out a joint faster and need more revision surgeries in their lifetime!