Minimising leg length inequality after total hip replacement.

The total hip replacement is one of the most effective medical interventions undertaken, with high reported rates of pain relief and patient satisfaction 1,2. Leg length inequality (LLI) following total hip replacement was first recognised by Charnley when the operation was popularised but has only recently increased in prominence in the literature. The definition of an unacceptable value of LLI is controversial and is complicated not only by the lack of agreement of significance but also by the fact that for any given magnitude of LLI, only a proportion will be symptomatic. This thesis begins by exploring the opinions of British Hip Society (BHS) members to generate an expert opinion on acceptable values. Findings were in broad agreement with the literature, with 6784% of respondents stating they believed that LLI of less than 10mm would always be within the bounds of acceptable practice.

A second survey of BHS members regarding methods of minimising LLI intra-operatively identified that 77% of surgeons use the Shuck technique during every total hip replacement, and that 11% use a commercial device. Chapter four evaluated five commonly used intra-operative tests and concluded that when used in combination these tests could produce acceptable values of LLI. Most reliance was placed on the Shuck technique during decision making.

Results from this work identified scope for development of a novel device to be used as an adjunct to the Shuck test as an indirect measurement of leg length. A device was designed and manufactured and preliminary results from in vivo studies show a narrow range of both distraction distance and force applied during the Shuck test. These results indicate that the device could be developed further to standardise the Shuck test and use it as an adjunct to train junior surgeons how to assess leg length, minimising the requirement for subjective and invasive methods.