We’re just starting to understand how different we all are. In the 1960s and even when I graduated medical school in the 80s, physicians believed that all of their patients were the same. In fact, much of our current regulatory SNAFUs regarding cell therapies are based on this premise. Turns out, we physicians were wrong, most everyone is quite different in everything from how they heal, to how they react to medications, to the quality of their cells. Case in point this morning is a new study that looked to see if genes could explain the differences in medication orders after knee replacement surgery, meaning is the amount of post surgical knee replacement pain genetic in nature. The authors looked at KCNJ3 (GIRK1) and KCNJ6 (GIRK2) gene variations (which like all gene names sound a lot like Greek). Basically they looked for SNPs or Single Nucleotide Polymorphisms in the genes. To understand SNPs, you need to know that the DNA that makes us different is like a dictionary of words and letters. SNPs are therefore like different spellings of the same word that are off by one letter. That one letter genetic difference can have a huge impact on which proteins are produced and how the body behaves, just like changing one letter in a key word can completely change the meaning of a sentence. What did they find? Sure enough, they identified a SNP that when found in a patient corresponded to significantly more post operative medication needs after a knee replacement. Freaky! They also found that they could add up these SNPs to get a pain risk score based on genes and that this also explained why some patients felt more low back pain than others. The upshot? When you’re sucking down the narcotics like so many M&Ms after your knee replacement, don’t blame your surgeon, blame mom and dad!
Knee replacement surgery recovery is a big deal. After all, the surgery involves the amputation of the knee joint and then the insertion of a prosthesis. As a result, knee replacement has been associated with side effects like a massive increase in heart attack risk right after the surgery. In addition, I’ve heard stories from patients for years about how their knee replacement recovery was hard. Most patients who have had this big surgery tell me that they weren’t really prepared for the pain and long recovery time. Now a new study shines some light on that recovery. The authors administered questionnaires to 174 patients who had undergone knee replacements at 2 weeks after their surgery. Participants rated pain expectation and severity, use of pain medications and alternative pain control methods, side-effects, walking and exercise times, perceptions of their pain medications, adequacy of pain management information provided and satisfaction with pain relief. [88 (52%)] reported that the worst pain period occurred during the first 2 weeks at home. During the first 2 weeks at home, the average pain was ‘severe/extreme’ for one quarter [40 (23%)] of the participants and more than half [92 (54%)] experienced severe pain at least some of the time. Many participants sought further medical help for their pain. Adequate information on non-medication based methods for pain relief was reported by only half of the patients [47%]. The upshot? Knee replacement surgery hurts a lot and it looks like the medical profession isn’t doing a great job helping many patients manage this severe pain.
What does a knee replacement cost? There was a great New York Times article on Sunday that reported that patients without insurance (and some with insurance), as being priced out of knee or hip replacement surgeries. One of the issues brought up is that the cost of a knee or hip device is controlled by monopolistic pricing. Basically, a “cartel” of five companies manufacture these devices. The sales rep and then hospital mark up these devices so that the final cost to the insurance company can be anywhere from $25-40,000. Unlike other areas of the economy, where having five companies all manufacturing the same thing would mean low prices, a combination of financial ties to surgeons, anti-competitive behavior, regulation and health insurance have kept these prices very high. Even if you decide to pay cash, the story points out that an implant that costs $150 in Asia will cost $13,000 here.
Faster partial knee replacement recovery is often touted as the rationale for why someone would want to replace only half their knee versus a total knee replacement. However, the research of the last few years hasn’t been kind to other minimally invasive knee replacement options like hip resurfacing. Will partial knee replacement problems also surface? First, the concept of a partial knee is that only one part of the knee is replaced, usually the inside or the outside compartment. Just googling “partial knee replacement” pops up a huge list of paid advertising by local hospitals hawking that this technology is the best solution for young and active patients, but is this supported by the research? Not really.
I first noticed an issue when this paper popped up in my daily search of the U.S. National Library of Medicine. A high volume knee replacement surgeons in St. Louis reported that out of 83 partial knee replacement surgeries, 11 of the prostheses had failed early. He concluded, “Based on these findings, including a high failure rate of the Oxford knee implant and the absence of any discernible learning curve effect, the principal investigator no longer uses this implant.” Ouch! So I looked deeper. This recent paper demonstrated that for some reason, patients were losing bone around this partial knee replacement device. This European paper states that younger patients (under 60 years old) had a much higher rate (more than double the risk) of wearing out the device early (needing a revision surgery). In addition, while the commercials for these devices tout them as long lasting in active patients, only 85% of them lasted 5 years!
The upshot? There is no free knee replacement lunch. All of these devices have issues. While there may be a faster recovery with a partial knee replacement, younger patients tear through these devices much quicker and they are not holding up well in all patients with only 85% of them lasting 5 years. I think when most patients get these devices, they believe that they’re good for 10-15 years about 100% of the time, this isn’t the case. So if you’re under 60 and active, despite the commercials showing younger active people, this may not be the technology for you.
Can you have a knee replacement allergy? Awhile back I blogged on knee placement and the studies showing that a good number of patients are allergic to various components of the prosthesis. A few weeks ago there was the “bald and itchy” patient who had lost her hair due to a metal allergy from a knee replacement. This week I followed up on yet another patient with severe knee pain and swelling after a knee replacement. Whenever I see this now my first thought is to rule out a knee replacement allergy. In this case, this poor woman had 2 surgeries due to wrong size prostheses and loosening of the device, a third surgery to break up all the scarring, and a fourth for another new prosthesis (not under my watch). I sent her out to National Jewish for allergy testing where they did an extensive analysis of not only the metals in her knee replacement device, but also the components of the cement used. Turns out she’s very allergic to one of the cement components, hence the loosing of the prostheses (her body was attacking the cement). This certainly explains her now chronically red and painful knee replacement site. While I have been able to get rid of her back, hip, and thigh pain with the Regenexx-PL-Disc procedure (they were talking about replacing her hip), she will likely forever have the knee issue until she decides to pull the trigger on a 5th surgery. She’s understandably not up for knee replacement surgery number 5, who could blame her? The upshot? If you’re an allergic person, do not get a joint replaced until you have been allergy tested for all of the device and cement components!
There are many younger patients these days that find themselves needing a knee replacement, This morning I’d like to write about a brother and a sister who both found themselves in that precarious situation. The 57 year old brother (GM) is our patient because a knee replacement wasn’t a perfect solution for his active lifestyle. As a result, he sought out a knee replacement alternative. He had already undergone a lateral meniscus surgery in 1998 and had tried prolotherapy. His MRI showed tears of the posterior horn of both the medial and lateral meniscus tissues as well as thinning and fraying of the articular cartilage with subchondral marrow edema and a chronic sprain of the ACL. He was told a knee replacement was the next step. Dr. Schultz felt he was a fair candidate for the Regenexx-SD stem cell procedure, so he decided to give it a try. Rather than injecting stem cells blindly somewhere into the knee joint, Dr. Schultz targeted his ACL under c-arm fluoroscopy and his meniscus using ultrasound guidance. The result on a recent 1 year registry questionnaire? No pain, no problem getting in and out of a car or climbing stairs, or sitting. He describes his overall improvement as excellent and more than 100% recovered. GM came to my attention yesterday when I was contacted by his sister who took the other route for her knee and underwent a knee replacement. She was surprised by GM’s recovery and wanted to know how it was possible that he improved through just an injection when her own experience of a knee replacement was such an ordeal. The upshot? Treating this patient’s knee required that we realize that his ACL needed to be targeted as much as his meniscus/cartilage and also that we use very precise placement of cells into these structures with more than one type of imaging. In addition, as I told his sister yesterday, like many other patients we’ve seen since 2005, a knee replacement is no longer the only option!
It should be noted that 100% improvement isn’t typical for the Regenexx-SD procedure. In addition, not all patients can expect this type of functional result.