Hip abduction pillow use following total hip arthoplasty does not decrease acute hip dislocation rates

Abstract

Dislocation following total hip arthroplasty (THA) is a complication with reported incidence rates varying from 0.5% to 10.6%. Post-operatively, placement of an abduction pillow is routinely undertaken to restrict hip movement as a precautionary measure to help prevent acute hip dislocation. Several recent prospective studies have however reported no increase in dislocation rates following non-restrictive protocols. Our primary aim is to compare the rates of acute hip dislocation between THA patients who received a post-operative hip abduction pillow (June 2014 - June 2016) and patients who did not receive a post-operative hip abduction pillow (June 2016- June 2018). This is a retrospective single-center, multi-surgeon case-series of patients who underwent primary THA between June 1, 2014, and June 01, 2018 at our National Orthopaedic Hospital. Exclusion criteria included revision surgery, conversion surgeries and patients who inadvertently received hip abduction pillows despite institutional change in protocol. Pearson’s chi-square test was used to compare dislocation rates between the 2 groups: reported as relative risk (RR) estimates with 95% confidence intervals (CIs) and P-values as appropriate. 1154 patients received hip abduction pillows following THA in the period June 2014-to June 2016. 1296 patients did not receive hip abduction pillows following THA from June 2016 to June 2018. Two patients suffered an acute hip dislocation in the period June 2014-June 2016) with 1 patient suffering an acute hip dislocation in the period June 2016- June 2018. The relative risk of suffering an acute hip dislocation was 2.25 times higher if the hip abduction pillow was utilized. Removal of the hip abduction pillow following primary total hip arthroplasty does not increase the risk of in-hospital acute hip dislocation, regardless of approach used.