Hip resurfacing offers new hope to young osteoarthritic patients. Increasingly in the US this procedure is suggested as a better alternative to hip replacement, though many sound a note of caution.Its potential advantages should be weighed against its potential risks, they say.
At the moment though, whoever could afford to in the US do scout around for hip resurfacing surgeons.
Osteoarthritis is a type of arthritis that is caused by the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is a protein substance that serves as a "cushion" between the bones of the joints.
Osteoarthritis is also known as degenerative arthritis. Among the over 100 different types of arthritis conditions, osteoarthritis is the most common, affecting over 20 million people in the United States.
Primary osteoarthritis is mostly related to aging. With aging, the water content of the cartilage increases and the protein makeup of cartilage degenerates. Repetitive use of the joints over the years irritates and inflames the cartilage, causing joint pain and swelling.
Eventually there is a total loss of the cartilage cushion between the bones of the joints. Loss of cartilage cushion causes friction between the bones, leading to pain and limitation of joint mobility.
But young athletes too are prone to osteoarthritis. Growth plate injuries are most common in boys aged 14 to 16 and girls aged 11 to 13 and are often associated with gymnastics, long-distance running, baseball/softball pitching, doctors say.
The growth plate is like a cap on the end of a long bone. Eventually, it will cement as the skeleton matures, but in children it is the weakest part of the skeleton.
Muscle strength imbalances, poor flexibility, inadequate strength training, overtraining, and lack of appropriate rest/recovery can contribute to the risk of overuse injuries,
Kids who are overweight or obese also have bone cartilage problems because the cushion can't support the weight.
Now while the aged osteoarthritis patients can go in for total hip replacement, youngsters have a problem.
In total hip replacement, surgeons replace a hip by cutting off the head of the thigh bone, the femur, and replace it with a metal ball mounted on a rod implanted deep in the thigh bone. A plastic socket replaces the original. Those artificial hips can bring tremendous relief to people crippled by hip pain.
But the metal-on-plastic friction means the implants can begin wearing out in about 15 years, sooner if sports or other activities increase pressure on the joint. For the average 65-year-old, that's no problem. But a 50-year-old, in contrast, could very well wear out an initial replacement and have little thigh bone left to fit another.
Surgeons lightly shave the damaged femoral ball and fit a metal ball snugly over it. That ball rolls in a metal cup reinforcing the socket. The idea: Metal-on-metal shouldn't wear out as fast, and if patients do need another replacement in 15 or 20 years, the thigh bone is largely intact.
"This resurfacing initiative has interest because we're sparing bone,'' explains Sheinkop, a Rush University professor and joint replacement director of the Neurologic and Orthopedic Institute of Chicago.
The operation hit the U.S. market last spring with Food and Drug Administration approval of the British-designed Birmingham Hip Resurfacing System. Competitors are in clinical trials here, and expected to clear FDA later this year.
More than 400,000 total or partial hip replacements are performed each year, a number growing as the population ages.
Doctors differ on what age is the cutoff for resurfacing, somewhere between 60 and 65, largely dependent on the patient's bone strength. Nor do all insurers cover it. The implant costs about 20 per cent more than a standard artificial hip.
Some studies suggest higher rates of failure in hip resurfacing, necessitating additional surgery.
In addition, there is some concern that the rubbing together of the metal parts used in hip resurfacing may produce very small metal particles that are absorbed into your bloodstream. The effect of these metal particles is unknown. However, a very small percentage of people may develop a metal allergy. Also, because these metal particles are eliminated by your kidneys, hip resurfacing is not recommended for people with impaired kidney function or diabetes.
Further research is called for before hip resurfacing is recommended as a most viable alternative to replacement is the consensus among the medical community.