Total Hip Replacement Surgery
Hip replacement surgery dates back almost one hundred years. The first attempts at replacing the joint were far from successful and were based on naïve mechanical principles and grossly inferior non-biological materials.
The real precursor to the modern hip replacement was first introduced by Professor Sir John Charnley in the late 1950s and early 1960s. He used a metallic stem in the upper end of the thigh bone made of stainless steel and a type of plastic liner in the acetabulum or pelvic socket. The first acetabular component was made of Teflon and, although it was of very low friction, unfortunately it did have a very high wear rate. The debris so liberated in the region of the hip joint gave rise to the formation of massive pseudotumours.
The next major step forward was to replace the Teflon with polyethylene. Even today in 2016 we still use a type of polyethylene to line the hip socket.
Modern materials now include titanium, cobalt chrome, ceramic and highly cross-linked polyethylene.
There are more than 150 types of hip replacement available. They vary in size, shape and material construct. All of them aim to replace what is normally a painful arthritic joint between the ball and the socket with artificial materials.
Revision Hip Replacement
Unfortunately, not all hip replacements will last indefinitely. Whilst a well-performed hip replacement can expect to have a survivorship of 90% at twenty years, some replacements will fail sooner than others. Reasons for failure include infection, aseptic loosening, excessive wear, recurrent dislocation or fractures around the implants that have been used.
Revision hip surgery is more complex than primary hip replacement surgery. This is because the tissues are scarred and damage has been created in that area giving rise to the eventual failure of the joint, and the risks are therefore increased concomitantly. Sometimes a revision can be quite straightforward and only one part of the joint requires replacing. At the other end of the extreme, the entire joint has to be replaced and significant bone grafting or the use of supplemental materials is also invoked. The risks of infection, damage to arteries or nerves, fractures, clots and haemorrhage are all increased.
Hip Preservation Surgery
The term “preservation” refers to the concept of keeping the patient’s own ball on the upper end of the thigh bone and own socket in the pelvis. Whilst the joint itself may be diseased in some way, there may be surgical methods available which can alleviate the discomfort and malfunction associated with the disease but still keep the hip intact.
This refers specifically to arthroscopic surgery or surgery involving osteotomies or division of bones aimed at redirecting the weight bearing forces within the joint.
