The world’s most successful hip resurfacing, the Conserve® Plus, is now FDA approved in the USA. This is good news for aging “baby boomers” and others looking for ways to maintain their active lifestyles and still have a long term success with a hip replacement. The Conserve® Plus device, manufactured by Wright Medical, is the culmination of my 30 years of research in resurfacing.
I performed a surface hip replacement on 32 year old Beth Barney 10 years ago when she was 22 years old. Beth suffered from osteoarthritis cause by a congenital dysplastic hip and was unable to stand or walk for any length of time without enduring pain. Her lifestyle was severely impacted by her hip pain including discomfort and pain during sleeping. She has had 4 children since her surface hip replacement surgery and experiences no pain or other impingement in her lifestyle or activities since her replacement. In November, 2009, Beth completed a triathlon, coming in first in her age group.
Don Holmes developed osteoarthritis and came to me in 2000 searching for an alternative approach to total hip replacement. An intense cycler, he was not prepared to give up his active lifestyle nor did he like the prospect of potentially needing revision surgery in 10 – 15 years if he chose a total hip replacement while maintaining high physical activity levels. I performed a surface replacement on Don who now rides over 4500 miles every summer and competed in the 2006 Death Ride 129 miles bike race in the California alps.
The population of patients who are candidates for a total hip arthroplasty is expanding, but most certainly includes the younger and more active individual seeking a minimally bone invasive procedure not only to relieve pain but also provide the ability to resume all pre-arthritis activities. Unlike total hip replacement that requires the top of the femur to be removed and a stem inserted into the bone shaft, hip resurfacing is done by removing only the pathologic bone then putting a metal “cap” over a reshaped femoral head, thus saving both the head and neck and not entering the intramedullary canal, and as such, is minimally invasive for the bone.
Hip resurfacing is the prosthetic solution that most closely matches the normal anatomy and biomechanics of the natural hip. The prosthesis’ large femoral head reduces the risk of post-operative dislocation while the metal-on-metal bearing allows the manufacturing of a thin, bone conserving acetabular component with very low wear rates. The femoral head and neck of the hip joint is preserved; its bone mineral density is preserved and maintained. These two factors also provide the best conditions for a successful conversion to a conventional, stemmed-type total hip replacement should this ever be necessary.
With hip resurfacing receiving a lot of attention in the consumer media, proponents of resurfacing see it as the ideal alternative to a total hip arthroplasty (THA) for the younger patient and now even for many older patients as well. While its detractors express a broad range of concerns--citing the technical difficulty of the procedure, the possibility of neck fracture and the potential toxicity from metal-on-metal ions. Fortunately femoral neck fracture is entirely preventable with good technique and none has occurred in my last 700 patients. The potential toxicity of metal-on-metal ions is minimal with well designed and implanted components. With the increased world-wide interest in this hip procedure almost every manufacture has ventured a “copy” of our hip resurfacing. Unfortunately two of these devices from large US manufacturers have recently been withdrawn because of design deficiencies.
Hip resurfacing is a conservative procedure, and I have performed more than 1,300 of the metal on metal hip resurfacings since 1996. The technique employing the current design preserves the acetabulum much better than the early generations of surface arthroplasty with a metal–plastic bearing. Now there is no more bone removed from the acetabulum than with a total hip replacement (THR). Additionally surgeons and their patients do not have to worry about creating a leg length discrepancy with hip resurfacing as you do with a THR because the components replace exactly the amount of bone removed. And, again, one of the most important advantages is the ease of revision if it is every necessary. The sockets are likely to be durable for 20 or more years, possibly a lifetime even in very young patients (our youngest was 13 years old), so that if revision is necessary the procedure is comparable to performing a primary THR. Because of this feature the risk inherent in performing high impact sports such as tennis, racquetball, running, etc. is less than with a THR because a revision, if necessary, is simpler and less debilitating than THR revision. Some of our early patients who are now 11-13 years post-op are regularly playing racket sports, competitive volleyball and one is even ballet dancing.
While many women are having excellent success and resuming high levels of physical activities after surgery, the ideal hips for this procedure are males with osteoarthritis and “normal bone stock” with a large head/neck ratio. The hips of those types of patients have a survivorship of 100% at 11 years. These superb results have caused us to increase our expectation for durability to last for a lifetime, hopefully even for young patients.
Many young patients whose hips were thought not to be candidates for resurfacing are now achieving comparable results due to technique and design changes introduced over eight years ago. Patients with risk factors for possible early failure include those with small size hips (most often women), and patients whose bone quality is less than ideal. However even with these we now can expect to have a survivorship of better than 97.6%. For both younger and older patients it is important to use an optimal resurfacing design and the Conserve® Plus has now stood the test of time.
About the Author
Harlan Amstutz, MD, Board Certified Orthopaedic Surgeon, performed the first total hip replacement in the United States in 1967. He is the founding director of the Joint Replacement Institute and Professor Emeritus and former Chief of Orthopaedic Surgery at the University of California at Los Angeles. Dr. Amstutz’s career has also included service as Chair of Orthopaedics at the UCLA Medical School and terms as president of numerous peer societies. Dr. Amstutz is recognized worldwide as a preeminent orthopaedic surgeon and researcher in the field of joint replacement. An American, British and Canadian (ABC) Fellow, Dr. Amstutz holds the Seddon Society Medal, the John Charnley Medal and the UCLA Alumni Association’s Professional Achievement Award. Dr. Amstutz was recently honored with a Lifetime Achievement Award by the American Orthopaedic Association (AOA). His decades of research have resulted in a device that leaves more of the bone in place, avoiding removal of the femoral head. Dr. Amstutz’s published book, “Hip Resurfacing: Principles, Indications, Technique and Results
,” is beautifully illustrated and contains information about biomechanics, techniques and instrumentation, including the author’s own CONSERVE® PLUS Hip Resurfacing System.
About Joint Replacement Institute
Worldwide leaders in the surgical management of hip, knee and shoulder arthritis, the Joint Replacement Institute surgeons have operated on thousands of patients, trained numerous other surgeons in less invasive bone-conserving techniques, been widely published in scientific research journals, and lectured worldwide. Joint Replacement Institute is an outpatient clinic of St. Vincent Medical Center, recognized by the Centers for Medicare & Medicaid Services (CMS) for outstanding achievement in clinical quality initiatives. For more information about JRI, visit www.jri-docs.com