Back then, the standard was a metal implant head in a plastic socket (polyethylene). This allowed for relatively little friction and caused only a moderate degree of wear.
However, it must clearly be noted that at that point in time, pain relief took center stage. The surgery itself was associated with such enormous risks that it was only performed when the pain was almost intolerable.
Some patients experienced such tremendous pain from arthritis that they claimed life appeared no longer worth living and were thus prepared to take any risk to somehow make the pain more tolerable. As a result, at that time, a number of ‘heroic surgeries’ were performed with the sole objective of reducing the pain (incl. amputation of an entire leg).
The first hip joint by Sir Charnley (pictured on the left) was therefore an incredible improvement, because it made the pain after a joint replacement tolerable in most cases. In those days, if it was possible to walk a few relatively pain-free steps, this was considered close to a miracle. Although these joints provided pain relief, they were certainly not suitable for hard physical tasks, not to mention athletic activities!
Nonetheless, the main problem, i.e. relief of the unbearable pain, was largely solved with the new joint. Preservation of tendons and muscles was not considered so important at the time since post-operative full function of the joint was not expected. During these surgeries, tendons were always detached or severed. Keeping muscles intact was often completely ignored. This is very different in modern minimal invasive hip surgery (see also MicroHip).
What were the main problems of these joints? There were mainly two: First, the joints were not very stable and because of this, frequently dislocated (luxation). Second, their survival rate was significantly limited. Depending on the loading, they wore down after just a few years and became loose. The mechanism of loosening certainly had several causes, but two problems stood in the forefront.