Hip replacements are so common now that it’s easy to take it for granted that we can have a new joint if our own hips are damaged by arthritis. This has only been possible for the last 50 years or so – hip replacement surgery really only became widely available from the 1960s.
The medical term for hip replacement surgery is arthroplasty and the first operations began back in the 1890s and continued experimentally until the 1960s. Doctors around the world tried different prosthetic joints and femur heads made from ivory or metal and some operations were certainly successful. Ivory femurs worked very well and, in the late 1960s, the Burmese orthopaedic surgeon San Baw reported a success rate of 88% in over 300 arthroplasty procedures. The American surgeon Austin Moore developed a metal hip prosthesis, a modified form of which is still in use today.
John Charnley – hip replacement pioneer
In the early 1960s, the greatest advances in arthroplasty were pioneered by Sir John Charnley, a British surgeon based at Wrightington Hospital near Manchester. The development of the technique of total hip replacement, which involves implanting a metal femur head and replacing the socket of the hip joint with a polyethylene cup, was his life’s work.
The idea of combining metal and polyethylene to make a complete artificial hip joint came to Charnley when he was trying to cure embarrassment in an early hip replacement recipient. The patient could walk well and was relatively pain free but his acrylic plastic artificial joint squeaked loudly all the time, so loudly that all those around him could hear it. After experimenting with several lubricants to reduce the friction that was causing the squeak, Charnley realised that the materials needed to make the prosthetic joint were not working. It took several prototypes but eventually he developed the Charnley hip prosthesis, which went on to be used in hundreds of thousands of complete hip replacements.
Extensive follow up for hip replacements
Charnley’s dedication to improving hip replacement surgery and the prosthetic hips he used is legendary. The success rates during the early years of arthroplasty surgery were excellent and Charnley always followed up every patient until they died. He wrote to each of them personally to ask if they would mind returning their replacement hip joint to him after their death. Most agreed and 10, 15, or 20 years later when the patient died, usually of a cause unrelated to their arthritis or hip replacement surgery, one of Charnley’s colleagues would arrange an operation to remove the hip joint and associated lymph nodes. By studying how each hip had worn, the changes to the patient’s own bone and muscle, and the inflammatory response, Charnley and his team were able to constantly learn how to make hip replacement surgery safer and more effective.
Recent developments in arthroplasty
John Charnley died in 1982 but many other orthopaedic surgeons have contributed to the development of better hip prostheses and new hip replacement operation techniques, for example:
New materials such as ceramics, titanium alloys and cross-linked polymers for longer-lasting prosthetic hip joints
Hip resurfacing – less extensive the arthroplasty to protect the joint from further damage
Minimally invasive hip replacement for faster recovery times