Muscle strength changes following different surgical approaches used in primary total hip arthroplasty: A Systematic Review and Meta-analysis

Background: Persistent functional abnormalities and strength deficits are commonly reported despite the advances in surgical approaches for primary total hip arthroplasty (THA). Understanding the influence of different approaches on hip muscle strength changes following THA may play a crucial role in optimizing post-operative recovery. Aim: Systematic review and meta-analysis of between-approach comparison of directly measured hip muscle strength following primaryTHA. Method: A comprehensive online database search was performed, identifying studies that compare muscle strength between at least two different THA approaches. Based on Cochrane guidelines, a qualitative and quantitative analysis was completed along with a meta-analysis of the eligible studies. ROBINS-i and ROB-2 were used to analyse the risk of bias, and the Pedro tool was used for quality appraisal. Results: 881 publications were appraised, yielding 23 eligible publications. Sufficient data for analysis was found only between posterior and lateral approaches for hip abduction strength in all categories. No statistically significant difference was found between the two approaches at 12 months and over time-period following THA (Z=1.51, P=0.13, Std Mean diff = 0.24, 95% CI [-.07,.56]). However, the results slightly favoured posterior approach. Additionally, no statistically significant difference found in the strength ratio of the operated side to the unoperated side (U = 15, z = -0.52, p = 0.69) or in the percentage change in muscle strength at 3 months (U=10, z=-.577, p=0.686) and 12 months (U = 10, z=-.577, p = 0.686) from pre-operative baseline. Conclusion: This systematic review and meta-analysis found no statistically significant difference between posterior and lateral approaches for directly measured hip muscle strength measured. Despite the increasing popularity of AA, ALA, and other minimally invasive or modified approaches, and the relationship between muscle strength and function, a sparsity was identified in published studies that performed a comparison between approaches of hip muscle strength.