Incidence and effect of leg length discrepancy following total hip arthroplasty

ObjectivesThe clinical importance of a leg length discrepancy (LLD) following total hip arthroplasty (THA) remains controversial. This study was undertaken to determine the effects of LLD on clinical outcomes at up to 3 years follow-up.Design and settingProspective, multicentre study.ParticipantsNine hundred and eighty-seven cases of primary THA, categorised into two main groups: the NoLLD group (LLD of less than 10 mm) and the LLD group (LLD of 10 mm or more).Main outcome measuresThe primary outcome measure was the change in Oxford Hip Score (ΔOHS) at up to 3 years follow-up. Secondary outcome measures were length of operating time and hospital stay, and revision and dislocation rates. Potential predisposing factors for LLD, including body mass index, age and type of anaesthesia employed, were examined.ResultsAt 3 years, the LLD group had a significantly worse ΔOHS [22.0; 95% confidence interval (CI) 20.5 to 23.5] compared with the NoLLD group (23.8; 95% CI 23.1 to 24.5) (P = 0.034). There were no significant differences in revision (P = 0.389) or dislocation (P = 0.220) rates between the two groups. Use of an epidural was associated with a decreased incidence of developing an LLD of 10 mm (P = 0.004).ConclusionA postoperative LLD of 10 mm or more leads to poorer functional outcomes. Further studies are needed to assess the impact of an LLD on clinical outcomes in the longer term.