Total Hip Replacement

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Total hip replacement is one of the most successful operations in the whole of surgery. It is an operation that has been around for a very long time and the results have been progressively improving. The designs, concepts and materials have changed over time and the surgical approaches have been refined. Today’s patient can expect a replacement to last many years and provide them with a relatively normal life style including quite high activity levels.

Currently materials include different metals, plastics and ceramics in lots of different combinations. The exact ones each surgeon chooses are those that they feel are best suited to the individual patient, taking into account their activity level, age and bone stock.

Conventional hip replacements provide a plastic socket in the pelvis and a metal stem in the femur, a small metal or ceramic head placed on the top of the stem articulating with the plastic socket. This is a very successful arrangement and has worked very well for many years. There is however an incidence of dislocation of these hips that can approach 1 to 4 %. The plastic in the past has tended to wear and the degradation products have contributed to loosening and bone destruction. Modern plastics are more robust but other articulations have been investigated.

Metal on metal articulations have been used also for a very long time, the first being back in 1938. Modern metal on metal articulations tend to be cobalt chrome and are manufactured to very high tolerances. They are produced in different sizes, a conventional size which has a small ball in a socket with a correspondingly small internal diameter, the metal surface often embedded in a plastic base, or large diameter, anatomical sized components which match the patients own sized hip.

The advantage of the large diameter bearings is stability, this being far superior to conventional sizes. This means that patients can mobilise fully weight bearing immediately post operatively with none of the restrictions dictated by the instability of smaller bearings. Therefore the inability to flex the hip beyond 90 degrees is no longer valid and patients can sleep on whichever side they like from the moment the surgery is complete. This lack of concern about the position of the hip takes away a lot of the worries that patients may have post operatively.

The socket component of this type of total hip replacement is identical to that of a resurfaced hip, the ball that matches it is attached to the top of a stem rather than being directly applied to the head of the femur but provides the same mechanics as a resurfaced hip and therefore the same post operative regimes.

This form of total hip replacement is relatively new and only has short to medium term follow up but there seems to be no particular reason at present to suppose that they are not going to last a long time.

It is this type of hip replacement that is performed by choice by Rowan Pool.

pre operative x ray of osteoarthritic left hip

post operative x ray of total hip replacement left hip