Research has Led to Better Implant Designs, Rehab Protocols
Scripps Clinic researcher Dr. Darryl D’Lima has been selected to receive the prestigious Nicolas Andry Award on June 11 for his research using a groundbreaking electronic knee prosthesis known as the “e-knee.” Presented by The Association of Bone and Joint Surgeons, the award recognizes a body of work conducted and published over an extended period of time that has significantly contributed to orthopedic knowledge and practice.
Dr. D’Lima has been at the forefront of e-knee research for more than 15 years. Scripps made history in 2004 when Dr. Clifford Colwell implanted the world’s first e-knee into a patient at Scripps Green Hospital. This unique “smart” prosthesis contains a computer chip that measures forces inside the knee while the patient participates in various activities such as walking, climbing stairs and exercising.
Researchers have used data from the e-knee to understand how forces affect the knee joint. These learnings have led to the development of better knee implants and improved rehabilitation protocols following knee replacement surgery. Since 2004, three additional patients have received e-knees. These newer implants measure forces in the knee experienced during the rehabilitation process.
Several awards and 27 articles in peer-reviewed journals have resulted from the Scripps research since its inception. Dr. D’Lima received the Nicolas Andry Award for his manuscript, “Lab in a Knee: In Vivo Knee Forces, Kinematics and Contact Analysis,” which will be published in the July 2011 print edition of the journal Clinical Orthopaedics and Related Research. Incorporating Dr. D’Lima’s entire body of work over the past 15 years, the manuscript reviews 25 studies including the design, development, and in vivo (within a living organism) usage of three generations of this electronic knee prosthesis.
With the e-knee, Scripps researchers have gathered data on all six components of force, and have used this to develop the first computer model of the knee to be validated with living human measurements. They have also used the e-knee to develop patient gait modifications and to test braces and orthotics that can reduce knee loads in patients with arthritis.
The latest generation of the e-knee includes continuous monitoring of knee forces. Results from this are being used to advise patients on their activities following total knee replacement, as well as to develop and validate computational models of the knee and enhance prosthetic designs and bio materials, among other translations.
Due in part to the aging and active boomer generation, the number of primary total knee replacements in the U.S. is predicted to grow by 673 percent – reaching 3.48 million – by the year 2030, according to a study published in the Journal of Bone and Joint Surgery. Additionally, given the growth in the number of procedures in younger, more active patients, implant longevity will require further enhancement. According to the American Academy of Orthopaedic Surgeons, by 2014 more than half of those needing total knee replacements will be younger than 65 years.
“The e-knee is unique in the research community and gives us an unprecedented ability to collect data,” said Dr. D’Lima, who directs the research laboratories at Shiley Center for Orthopaedic Research and Education (SCORE), part of Scripps Clinic in La Jolla, Calif. “Research like ours is going to become increasingly important, as health care reform begins and insurance companies demand proof of efficacy before offering reimbursement for treatment.”
Scripps’ research may also help orthopedic surgeons predict how long prosthetic joints will last within individual patients following joint replacement surgery – thus allowing people to modify their lifestyle in such a way that their implants last longer. According to the National Institutes of Health, the average artificial knee joint lasts 10 to 15 years before it needs to be replaced. However, its useful life could vary, depending on a patient’s weight, the amount and types of physical activities and other factors.
“We’ve encountered some surprises in our research, including the high forces measured during golfing and the low forces measured during biking,” Dr. D’Lima said. “Also, activities measured outside the lab such as unsupervised hiking generate almost twice as high forces, compared to supervised data collection in the lab. Stresses placed on the joint can be remarkable; one patient stumbled and put five times body weight on her knee.”
Dr. Colwell, SCORE’s medical director, will present the research and accept the $15,000 award at the Association of Bone and Joint Surgeons’ Annual Meeting at The Westbury Hotel in Dublin, Ireland from June 8-12, 2011. A 2006 e-knee recipient, physical therapist Sue Carpenter, will join Dr. Colwell.
This marks the second time that a Scripps orthopedic researcher has received the Nicolas Andry Award, which is sponsored in conjunction with the journal Clinical Orthopaedics and Related Research. In 1997, Dr. Colwell received the same award for his lifetime work in the area of venous thromboembolic disease. No other institution or research team has received the award twice. The award is named for French physician and writer Nicolas Andry, who played a significant role in the early history of orthopedics.
SCORE researchers will use the grant for ongoing research on the e-knee and development of the next generation of the device. One goal is to create a “smart knee” that can monitor wear, detect infection, and sound an alarm if there is a problem. Researchers are also working on a sensor that could be used during total knee replacement surgery to help distribute forces across the knee joint and make implants more durable.
The Association of Bone and Joint Surgeons was formed in 1947 to advance the science and practice of orthopedic surgery. The national association’s mission is to create, evaluate and disseminate new knowledge and facilitate interaction among all orthopaedic specialties.
Dr. D’Lima is also an assistant professor in the Division of Arthritis Research at The Scripps Research Institute and an associate professor at the Scripps Translational Science Institute, and holds the Clifford W. Colwell Jr., MD Chair in Orthopaedic Research.
- Stephen Carpowich