Hip Replacement Is Now a Routine Procedure for Arthroplasty Specialists
In a healthy individual, the articulation between the pelvis and the femur is a smooth process, essential to many human activities, and one that is easily taken for granted for as long as it remains so. However, damage resulting from injury, as well as that caused by a number of medical conditions, can affect the smooth functioning of this joint, resulting in pain and often leading to diminished mobility. Prior to the development of successful hip replacement techniques by orthopaedic specialists in the early 20th century, attempts at implantation were largely ineffective and the treatment of these conditions tended to focus mainly on pain relief, rather than on reparative procedures.
The root of those early failures lies less in the techniques employed by the surgeons and more in the limited materials available for the construction of prosthetic joints. The earliest documented attempt at this kind of intervention took place in 1891 when a German physician and surgeon named Themistocles Glück began replacing the damaged femoral heads in patients affected by tuberculosis. He used prostheses fashioned from ivory which, unfortunately, were not well-tolerated by the host tissue. Although still far short of the hip replacement technology employed by modern specialists, the first use of a glass mould, in 1925, to encase a damaged femoral head, though it proved to be too weak and quickly shattered, led to experiments with metal prostheses. In the ‘50s, this would spark a revolution in the development of arthroplasty.
The first materials chosen for these metal-on-metal (MOM) prosthetic joints were stainless steel and an alloy of cobalt and chromium. Even though their survival rate proved to be a vast improvement, some early failures revealed loose particles of metal when attempting revision procedures and MOM prostheses were largely abandoned in favour of the low friction arthroplasty technology developed by the British orthopaedic surgeon, Sir John Charnley during the early ‘60s. Today, much of the hip replacement surgery performed by specialists worldwide is still modelled on Charnley’s basic three-part model. His prosthesis consisted of a femoral stem of metal designed to articulate with an acetabular cup fashioned from ultra-high-molecular-weight polyethylene (UHMWPE). Each of these components was secured in position with the use of acrylic bone cement.
In hospitals all over the world today, tens of thousands of partial and total hip replacement surgeries are conducted by arthroplasty specialists each year. These procedures are transforming the lives of patients who, without them, would almost certainly have been condemned to living out their lives in pain and unable to move without the aid of a wheelchair. Total hip arthroplasty (THA) is widely considered to be the most successful orthopaedic intervention of all time. Some of this success can be attributed to the parallel development of a procedure known as arthroscopy.
In the traditional approach to this surgery, access to the joint and surrounding tissue is obtained by means of a single 25- to 30-centimetre incision, enabling the muscle to be split or detached, and the joint to be dislocated. Although not suitable for all patients, hip replacement is frequently performed by specialists in arthroscopic surgery. It requires special instruments and is performed using either one or two incisions, in each case, half the length or less than that required by the traditional approach. Using this technique, trauma to tissue is much reduced, as is post-operative recovery time. In general, this form of arthroplasty is best suited for those individuals who are otherwise in good health who will be able to engage more actively in the rehabilitation process.
Research into many aspects of hip replacement has been ongoing. Consequently, specialists now have a number of new options at their disposal. One such option is titanium foam. This hi-tech material resembles the structure of bone and behaves more like it when placed under stress. In addition, the porous structure of this bio-compatible encourages the ingrowth of bone, and the subsequent fusion between bone and metal serves to provide improved stability. In addition, despite their higher cost and the occasional tendency to be noisy, ceramic-on-ceramic prostheses have been gaining popularity in many central European countries.
Closer to home, the arthroplasty unit at the Life Wilgers Hospital in Pretoria has become the focus of referrals both from within South Africa and internationally. The unit is staffed by a team of specialists in the procedures for hip, knee, and shoulder replacements under the leadership of one of the nation’s most experienced and accomplished orthopaedic surgeons.