Stanford Surgeon, Army Commander, High Heels, and OA…Put THAT Together
She has commanded an Army image intelligence unit and is now professor and vice chair of research in the department of Orthopaedic Surgery at Stanford University. Now, Constance Chu, M.D., is investigating osteoarthritis and high heels. Dr. Chu told OTW, “My overarching—no pun intended—goal is to investigate the mechanical, structural, and biological aspects of osteoarthritis (OA) all together. We often approach OA from only one of these and end up falling short. In collaboration with Tom Andriacchi, Ph.D., professor of mechanical engineering, we are finding that women walking in high heels show gait patterns similar to people with osteoarthritis. The good news? You remove the heels and the gait changes completely reverse themselves.”
“High heels keep most people from fully straightening the knee when walking. This can put more stress on the kneecap and other parts of the knee. Interestingly, when someone tears the ACL or is elderly, we see similar gait changes. And, these are high risk groups for knee OA. While it can be hard to know whether the gait changes cause osteoarthritis, or are a result of the disease, being able to readily change this variable through shoes will enable us to better study these questions. Going forward, we are planning to evaluate high heel warriors (lifelong devotees of high heels) to see how they may have adapted to the shoes.”
“My ultimate goal is to provide personalized OA risk evaluation, something that is not being done anywhere as of yet. I want disease modification, so I’m most excited by the fact that a simple action of changing one’s shoe can reduce or eliminate what I believe to be a high risk movement pattern. Going forward we are planning a systematic evaluation of how different shoes can be used to reduce knee loading for people with knee pain and risk for osteoarthritis.”
American Joint Replacement Registry Taking Off!
Growing, transparent, and led by professionals who have “been there”…sounds like a superb way to shape a registry. David Lewallen, M.D., an orthopedic surgeon with Mayo Clinic in Rochester, Minnesota, is the medical director of this initiative—the American Joint Replacement Registry (AJRR). Dr. Lewallen, past president of both The Hip Society and the American Association of Hip and Knee Surgeons, commented to OTW, “At this point we have collected over 150, 000 hip and knee arthroplasty procedures in the AJRR registry since its inception in 2008 and we are adding roughly 2, 500 new procedures per week. There are over 380 hospitals that have signed on and we have just released our first formal annual report (which covers the period through January 1, 2014).”
“The real plus for hospitals and surgeons is that it’s a way of collecting their information in an organized fashion that gives them a chance to be benchmarked against national metrics. The ability to segment the data to hospitals of similar size is extremely valuable. This means that academic centers can assess the quality of their services and compare them to other large academic centers as opposed to, say, a small suburban hospital outside of Chicago. One reason such apples-to-apples comparisons are important is that the case mix in hospitals varies greatly…and it’s important to be able to risk adjust the information. Being able to do this gives value, meaning, and context to the data we are providing.”
“We are unique among registries in that we are an independent 501c3 with a multi stake holder board and governance. We have representatives on our board from the American Academy of Orthopaedic Surgeons, The Hip Society, the American Association of Hip and Knee Surgeons, the Knee Society, the CEO of a Chicago area hospital representing the American Hospital Association, two members from health insurance companies, representation by Orthopedic Industry from the Advanced Medical Technology Association, and most importantly a board seat for the chair of our separate AJRR Public Advisory Board. Such participation helps ensure a wide range of viewpoints, and goes a long way to ensuring transparency.”
“An additional way that the AJRR can benefit surgeons is that it can serve as a venue for surgeons to meet their documentation requirements to the Centers for Medicare and Medicaid (CMS) for the Physician Quality Reporting System (PQRS). After 2015 physicians who are not providing the appropriate quality reporting documentation to CMS will be hit with penalties. Doctors participating in our registry can use the AJRR as a means of supporting these reporting requirements.”
“A year from now we will likely we’ll be surpassing 250, 000 procedures in the registry; as we obtain longitudinal follow-up we will start looking at survivorship of implants. If you look at other national registries most of them start putting out interesting information about survivorship at five or six years into it. We are already able to give descriptions of the practice of arthroplasty care in the U.S. Note that CMS data only provides the Medicare piece— nearly 50% of arthroplasty procedures are done in non-Medicare patients, where national practice patterns and results have been a bigger question mark for a long time.”
“Thus far, we can say that the mean age of patients in the registry is around 67 years for both hips and knees. We also have information on the most common causes for early revisions: for both knees and hips, it is infection. However, in hips periprosthetic fracture is a close second at 30.7% of revisions in the first three months postop.”
“I’m also pleased that we have the ability to track new technologies as they become available. For example, to our surprise we’ve found that in a subset of total knees performed in 2013, 75% of them were done by surgeons using highly crosslinked polyethylene (XLPE). This is novel information about current practice trends, and is especially important given that this is a relatively new technology. This is just one example of the detail and clarity that our registry can increasingly provide as time goes by. For surgeons interested in participating in the AJRR, helping to get their hospital on board, or in simply getting more information on our registry, they can contact me directly or any or our AJRR staff at: www.ajrr.net ”
Implant Choices: From Hemming and Hawing to Statistical Reasoning
Eric Swart, M.D., a resident at Columbia University, often witnesses the rather unscientific decision making process that his peers undertake when deciding whether to use an expensive or a “budget” hip implant. He and his colleagues decided to embark on a cost effectiveness analysis in order to attain statistics-based clarity. Dr. Swart told OTW, “I’ve witnessed a number of my colleagues taking the conservative route (the expensive implant) with implant choices because if there was a problem someone would say, ‘Why did you use the cheap implant?’ My colleagues and I decided to do a study on the parameters that can be used in order to make cost-effective implant choices; our focus was on intertrochanteric hip fractures.”
“We have historically used the rather inexpensive extra medullary sliding hip screw when it comes to stable fracture; with unstable fractures, however, we have most often used the more expensive intramedullary nail. We used an expected-value decision-analysis model in an attempt to estimate the total costs and health utility based on the choice of one of these two treatments. One of the things that made this especially difficult is that our treatment is evolving with time. It’s hard to look at the data from 15 years ago and say that it applies today. Techniques have changed, as has recognition of what is necessary for surgeons to be successful. The good thing is that these modeling techniques can help get over some amount of uncertainty and still give you [an] answer.”
“Our research team found that fixation failure rate and implant cost were the most important determinants of implant choice. We found that hip screw fixation is more cost-effective in cases where there is stable fracture or in cases where the stability is in question; using a nail was found to be more cost-effective for reverse obliquity fractures.”
“Some patterns are simple and are clearly stable and surgeons all agree that the less expensive implant is the way to go. Some agree that with a sub trochanteric fracture you need an intramedullary nail. But with a comminuted fracture most people think, ‘Geez, I don’t know. I should probably just use a nail.’ Our analysis reveals that this decision doesn’t ‘buy’ you very good results. If I could control the next 10 years of research I would focus on getting better primary data and looking at a more reliable classification of fracture patterns. There is an extraordinary lack of agreement on this issue.”
