Leading London orthopaedic surgeon Warwick Radford says: “Charnley’s successful metal on plastic hip replacement had the smallest diameter (22mm) of any design of hip replacement (then and now). Small diameters result in less friction but are more likely to dislocate. So a larger diameter ball is desirable both for stability (i.e. less likely to dislocate) and for greater range of movement.”
Anyone seeking to discuss hip replacement options with their doctor should also be aware that, “larger balls have a larger surface area and therefore generate more wear particles (which is bad) although the newer materials make this less of a problem. The popular larger diameters were 28 and 32 millimetres, but with more wear resistant components even larger diameters can now be used, e.g. 36 millimetres and above.
It all depends on the need of the individual patient and so it is well worth looking at the top tips for hip ops in this article.