News 01/12/2008

Featured Article: Hip Replacement Surgery

A NEW OPTION

We had a distinguished visitor in Bangkok this month Dr Derek McMinn, the pioneer inventor of a technique known as the Birmingham Hip Resurfacing operation came to the Bangkok Hospital Medical Center. He gave presentations, held teaching sessions and performed the operation on a very grateful Thai lady. Dr Sombat Rojviroj, the Chief of the Department of Orthopaedic Surgery proudly announced that the hospital is now fully trained and equipped to perform this innovative new operation.

The story of Hip Replacement surgery is an interesting one. The hip joint one of the strongest and most important joints in the body has to withstand an enormous amount of pressures during its life. There is hardly a movement of the body that does not involve the hip and the stresses it is exposed to are enormous. It is a fairly simple joint if you look at it as a piece of engineering; a simple ball and socket joint. The femur, the thigh bone, ends in a round ball and this articulates into the acetabulum, a cavity in the pelvic bone. Over time the articular cartilages which cover the two surfaces wear out and the two raw bony surfaces rub together. This is very painful and can make walking difficult and running impossible. For years many older people have been forced to use walking sticks to walk as the pain is so intense. This inactivity can have effects on other parts of the body and the lack of exercise can shorten life.

Attempts had been proposed and attempted even in the nineteenth century but it was the pioneering work of one man, Dr John Charnley, that led to the development of modern Hip Replacement surgery. He started working on the problem in the nineteen fifties but it was not until 1962 that he was first able to perform the first successful operation. Today he is widely respected for his work, but at the time many of his colleagues in the world of Orthopaedic surgery were skeptical about his project.

He worked at Wrightington Hospital, just outside Manchester in the North of England. He was a very determined man and was convinced that he could solve the problem. He built his first laboratory in a building that had been a tuberculosis sanatorium before the Second World War. This was not a well financed research center and attracted very little research money but was a very practical medical-engineering laboratory. There, he and his technician experimented with a number of different metals and plastics before he discovered a suitable pairing.

He remarked afterwards that he had often recalled Winston Churchill's remark that success often depended on the ability to proceed from failure to failure without loosing your enthusiasm.

Charnley was an accomplished thinker and engineer. As it is essential to preserve a totally sterile environment at the site if the operation, he also reinvented a new way to ventilate operating rooms, a technique that is now used world -wide.

In 1962, in what was his third series of operations he achieved success. Within a few months the news of Charley's successes had spread and surgeons from all over the world came to Manchester to study and be taught by him. His work was eventually recognized and his name is known throughout the world. The Queen honored him by creating him a knight, Sir John Charnley a few years after his triumph.

Over the years many changes have been made to the original design and a variety of implants are available.

Metal femur and metal acetabulum, metal on plastic and ceramic on plastic have all been tried, A metal femur replacement into a plastic acetabulum, as proposed by Charnley, has proved the most successful. In a total Hip Replacement the top of the femur, the long bone in the thigh, is removed and a metal duplicate is inserted to replace the removed part. In the pelvis, the old socket is enlarged and an implant, often a metal base with a plastic liner is inserted into the pelvic bone.

Osteoarthritis of the Hip is a problem seen in patients of fifty and upwards and for the most part hip replacement has been a very suitable answer. Given a reasonable quiet life-style a hip could be expected to give twenty or more years service. For the young very active patient there was a problem. If such a patient had an implant in their forties or fifties then there was a chance that the patient would wear out the hip in less than twenty years and would be left in a difficult situation in their seventies.  Other problems can arise after conventional Hip replacement. The two legs may be of slightly different lengths and there is a possibility of the hip becoming dislocated. There is also some wear and tear and the plastic part in the pelvis may start to crumble and debris can gather. In the Resurfacing operation the joint is a metal to metal joint and this does not occur.

The Hip Resurfacing operation overcomes both of these complications and for these active young people the operation is a better option. Patients have run Marathons, climbed mountains and played active sports after the operation with no pain or lack of movement.

The other advantage is that after several years the resurfaced hip should encounter problems-then a total Hip replacement can be performed.

Hip Resurfacing, a technique where most of the femur is retained and a new ball portion attached to the neck of the femur had been tried many times and had not worked out. Dr McMinn and his associates in Birmingham in England were convinced that this could be the answer for younger patients.

The story is very similar to the Charnley story; many Orthopaedic Surgeons considered their efforts to be a waste of time and were skeptical about their results.

Dr McMinn started to perform his operation in1997 and now after ten years his work has been recognized and again Orthopedic Surgeons have been traveling to England to learn his technique.

The Bangkok Hospital Medical Center has had an excellent Orthopaedic department and for many years has been performing hip replacements. Now they are fully equipped to perform the new Hip Resurfacing operation. Dr McMinn came to BMC and performed his operation and worked with the hospital staff to perfect their technique.

The choice of which operation is correct for any one patient is a complicated one. Dr Sombat Rojviroj and his team of Orthopaedic Surgeons are skilful in assessing each patient, their disability level, their activity level and their bone strength and advising the correct procedure. If you are having pain in your hip on walking make an appointment to see them.

Dr Michael Moreton is the International Medical Coordinator at the Bangkok Hospital Medical Center. He will be happy to answer any Health Care questions.  Moreton@bgh.co.th

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