Orthopedic Research
The Orthopaedic Biomedical Imaging Institute at Vanguard Weiss Memorial Hospital is an independent research facility affiliated with the University of Chicago. Cofounded by Dr. John M. Martell, the Institute conducts unbiased research. Studies have been funded by Biomet, DePuy, Smith & Nephew, Stryker, the Harris Foundation, Zimmer, and grants from the National Institutes of Health.
The Institute is currently focused on four major areas of research:
- Radiographic wear analysis in total hip arthroplasty
- Radiographic wear analysis in total knee arthroplasty
- Radiographic determination of hip joint reaction force
- Osteolysis prediction and early radiographic detection in total hip arthroplasty
Dr. Martell’s renowned hip analysis technique is used by colleagues nationally and internationally, and he continues to collaborate with experts in biomaterials and total hip arthoplasty.
Review Dr. Martell’s most current research below:
Dr. Martell is the co-recipient of the Hip Society’s John Charnley Award for 2012 for his latest research entitled, "Clinical Multi-center Studies of the Wear Performance of Highly Cross-linked Remelted Polyethylene in THR.” According to the Hip Society, this award recognizes innovative research, either clinical or basic, encompassing important advances in the management of hip disorders.
Advancements for the “Decade of the Hip”
About 250,000 people get total hip replacements every year, a number expected to reach 572,000 by the year 2030 as Baby Boomers age. It is a statistic that makes research on joint implants even more important, especially for younger, active adults, faced with total hip replacement.
Whether through injury or arthritis, patients in need of hip surgery are seeing improved care in what orthopedic surgeons at Weiss Memorial Hospital are calling the “decade of the hip.” New surgical techniques, prostheses innovations and research on the longevity of joint implants are expected to advance the treatment of the hip like no other time in history. Research at the Institute helps determine the best materials to use for total hip arthroplasty, thereby preventing bone destruction and loosening of the implants and avoiding costly revision surgery. These exciting innovations greatly benefit all total hip patients, particularly those with high demands whose implants may now last a lifetime.
Dr. Martell has been studying hip joint wear for more than three decades, looking at how the ball of the joint rubs against the cuplike socket and wears it down. He uses computerized wear-measurement techniques in his lab to analyze X-rays of patients’ hips over time—those from people who are both active and more sedentary. His research has found that metal-on-highly-cross-linked-plastic implants are durable and cost effective for the greatest number of patients. The highly cross-linked polyethylene liners have been used since 1999. The manufacturing process involves a short burst of radiation, which forces the layers of plastic to “link up” and help the cup resist wear.
Part of Dr. Martell’s research is published in a recently released study in the Journal of Arthroplasty, 2010, (The Daily Activity Questionnaire: A Novel Questionnaire to Assess Patient Activity After Total Hip Arthroplasty), which shows the wear is minimal even with a high level of activity.
About Hip Implants
All hip implants have a ball and socket that consists of either metal on metal, ceramic on ceramic or metal/ceramic on polyethylene. They all have their advantages and disadvantages. Some shed microscopic particles over time that could lead to problems, albeit rare. For example, polyethylene particles in the body could cause joint inflammation or osteolysis, a dissolving of the bone. Metal ion particles could result in a tissue reaction called ALVAL, aseptic lymphocyte-dominated vasculitis-associated lesion, or a toxic reaction called pseudotumor. One advantage of a metal-on-metal implant is the ability to have a larger femur ball and socket to prevent dislocation in active patients. Ceramic has virtually no distribution of wear products in the body, but is the most expensive of the materials and has been known to “squeak” in a small number of patients.
Research is proving that the metal-on-highly-cross-linked-plastic implants are durable and cost-effective for the greatest number of patients. Dr. Martell believes the highly cross-linked polyethylene [plastic] hip cup liner will be the most cost-effective implant having the greatest impact on hip replacement surgery in the future.
Implant makers are enhancing the plastic by treating it with vitamin E, a natural antioxidant that is expected to improve the longevity of the implant; already it has shown less wear than some other polyethylene liners.
Contact the Institute at (773) 564-5190 for more information on joint research currently under way.
Learn more about the Orthopedic Research Team.