Hip Relining Suits Younger People

MANY thousands of younger people who are crippled by arthritis may soon be able to have damaged joints relined rather than undergo an operation for total replacement of, for example, the hip.

The new technique has evolved through pioneering British surgery techniques developed at the Royal Orthopaedic and Nuffield hospitals, at Birmingham, English Midlands. It has already been applied with success to 500 patients, including a national judo champion and a national badminton player, both now back in action after the operation.

It involves relining joints to achieve the same effect as total replacement, with less invasion and with far greater liberating results, the researchers claim.

Hip joints affected by osteoarthritis become painful and swollen when the bones rub together as cartilage is diminished and eventually lost. Conventional treatment involves an operation during which a surgeon has to cut deep into the femur (thigh bone) to allow a plastic or metal joint to be fitted.

The alternative technique simply involves replacing the diseased tissue with a metal-on-metal lining, which contains a bonding agent, to stop the rubbing. The amount of bone removed during this operation is minimal compared with that needed to be taken away in total replacement surgery. A further complication with the replacement route is that it leads to further bone loss because the artificial joint interferes with growth.

Total hip replacement operations, developed by the late Sir John Charnley 40 years ago, are acknowledged worldwide as one of the most successful techniques in the history of surgery. In the United Kingdom alone there are 40,000 hip replacements, and a further 13,000 revision operations to replace loose artificial joints.

The relatively high number of the latter operations is because an artificial hip joint is more than likely only for life if the patient is elderly when the initial operation is performed and does not engage in sports such as tennis or football.

Despite his successful and innovative total hip replacement work, Sir John is reported to have always believed that this technique was second best to a simpler 'resurfacing' operation. According to Derek McMinn, a consultant at the Birmingham hospitals, Sir John only failed in his quest because of the lack of the right material. He chose Teflon, but this wore out within two years, making further surgery necessary.

For almost 10 years the search for a strong, practical lining material continued and it was not until 1991 that the Birmingham research programme began to discover a winning combination. This involves a metal head which is fitted to the femoral head and which engages with a metal cup implanted to replace the cartilage layer.

Although the operation has been overwhelmingly successful, it is still officially classified as 'unproven', and Mr McMinn believes it will stay that way for 10 years or more until doctors establish how long the benefits will last.

This is one reason why Mr McMinn still recommends total hip replacement for older patients. He explains: ``We just do not know what the failure rate of the new procedure will be. In contrast, in old people total hip replacement has a proven success record.'' In elderly people, 80 per cent of total hip replacements last 20 years; while in younger ones, there is at least a 50 per cent failure rate within 19 years.

Mr McMinn points out that resurfacing needs good quality bone and would not suit, for example, an elderly person with osteoporosis (fragile bones). He also emphasises that he does not encourage patients who have undergone relining surgery to take part in sports but adds that they have an average age of 48 and many do resume sporting activities following the operation.