Saturday, March 25, 2023

Thoughts on osseointegration…

Thomas Cutler

Hello Listserv,It is a beautiful Sunday afternoon and what better way to enjoy the transition to summer than by delving once again into a prosthetic topic? Okay, granted, enjoying a margarita may be a better way, but surely you can multitask, right?
So, I had a few questions about osseointegration.
But first, we have to know about that with which we are dealing, right?According to Jagers, 1995, active TF amputees have 50% de-mineralization of the femoral shaft in just 2 years. (statistic found on first page of full text, not in abstract)Bone testing for osseointegration has been done on cadavers…of normal people. Isn’t that going to be with bones 200% stronger than the actual amputee candidates? Again, just a question…or am I incorrect? According to some statistics, non-infection complications (fractures, loosening, etc) can reach 30%. Infections, whether big or small, are higher. But don’t worry, it’s, um, fine. 30% is the failure rate of the metal on metal hip implants for Johnson & Johnson. When that happened, they simply spent over $3,000,000,000 to take care of it. Problem solved!The protocols of the surgery are one or two stage. Each one may include 2 to 6 months of non- or partial weight bearing. Other places say up to a year before they finally walk optimally.From what I have seen, none of the osseointegration configurations allow weight bearing on the components. I really like a recent find (and would like to get my colleagues to weigh in–the reason for this post). Some guy contacted me on Linked In from Keep Walking implant. After first ignoring him, I looked at his POI article. It showed that they got a 25% increase in walking speed with amputees with their implant. Huh…I read on… What is the implant? I look at it like a “quickie Ertl” for TF. The Ertls, God bless ‘em, have been promoting this procedure for three generations. As we all know, this has been difficult with regards to gaining widespread traction with surgeons. Then again, when the surgeons get to a point where they think “I have failed to save the leg” and “well, now it’s a salvage procedure”, I doubt that they want to increase their involvement and develop expertise here. I have had vascular surgeons tell me to my face, “Tom, I am glad to help on that revision, but I really don’t want to get a reputation as the ‘amputation expert’, okay?”So, with the Keep Walking implant, they walk once the incision is healed. They weight bear on the implant. They hope to restore bone density. They walk quite a bit faster. Everyone is thrilled…but then I looked at the article again. It said that they were measured for pain levels. Huh? So, what were the results? It was nowhere to be found in the POI article. So I reach out to the Linked In guy…82% decrease in pain level. What the??? So, 25% faster and 82% less pain? I go back to the Ertl article in the OandP Edge 2010 . #3 on their list was the fact that the Ertl closes/seals the medullary cavity of the femur.
Now, here are my questions:
How important is closing the medullary cavity of the femur? This is the place where bone marrow (red marrow and yellow marrow) is stored. So, we freak out about leaking crude oil into the ocean (crude is just prehistoric ferns and plants, right?), but reimburse for a procedure that may leak bone marrow into the body? Again, just asking questions. Now, I totally agree about the limitations of sockets. I am a strong advocate of skeletal capture and use the HiFi. But why claim that socket design is flawed and jump right past a number of intermediate stages to claim that abutment, or percutaneous osseointegration, is the “gold standard”?If you can prove that an open medullary cavity is fine, please do that. I am sure that the articles would be out there, but I haven’t found them.If you can prove that providing weight bearing has no significant benefit to my patients, please do that.
Now, I told the HiFi folks to reach out to the Keep Walking folks and see what is possible when you stabilize the entire shaft of the femur. I feel like the Jewish matchmaker from “Fiddler on the Roof”!Question: if skeletal capture, weight bearing and a sealed medullary canal resolve a huge portion of our issues, why do this “nifty” stoma thing with “only” 30-something percent infections and 30% “issues” like splitting femurs, etc? Again, if you have the reasons, cool! This makes for an amazing discussion on this list serve and we are truly a profession.
Don’t we all just want what’s best for the patient here?
The what??? Right… the patient. One more question (maybe just one). If “patient-centered” care is the point of everything we do…If you truly value the input of the person having to deal with, not just the hassles of the socket, but the hassles of osseointegration, wouldn’t their choice to revert back to an intermediate step be a valid factor in weighing what we consider to be the “gold standard”? You see, the Keep Walking implant seems to fix a lot of stuff. But it is also a modular system that converts to an abutment/percutaneous system typical of the other osseointegration configurations. But if the patient doesn’t like it, they can simply revert back to the weight bearing spacer system. What does this do? It provides legitimate opposition from the most legitimate source of all. The patient. This makes the surgeons and designers really step up their game, really come up with what is truly the best option as decided by everyone involved, including the patient. Because if 83% of patients reject the stoma and prefer something else, it tells us how important choice and accommodation is for available systems (and yes…I just totally made up that number. Again, I am not advocating, merely inquiring).
Now, prosthetists, don’t celebrate too quickly…If you give TF patients a weight bearing residual limb, you are going to have to “up your game” as well because the “no prosthesis” option just started looking a lot better…
So, esteemed colleagues, –has OI testing been done on a foundation of comparable femurs?–is sealing the medullary canal important?–have we done due diligence exploring intermediate interventions?–Should the patient get a say in converting a system back to their preferred configuration?
I look forward to hearing thoughts on this and reading the articles that I must have missed regarding osseointegration.

Thomas J. Cutler, CPO, FAAOP, CPHMLimb.itless, LLC113 N. Church StreetSuite 312Visalia, CA 93291559-334-3741 phone559-553-8837 fax


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