Motor Nerve Palsy After Direct Anterior Versus Posterior Total Hip Arthroplasty: Incidence, Risk Factors, and Recovery

Background: There is limited literature on motor nerve palsy in modern total hip arthroplasty (THA). The purpose of this study was to establish the incidence of nerve palsy following THA using the direct anterior (DA) and postero-lateral (PL) approaches, identify risk factors, and describe the extent of recovery. Methods: Using our institutional database, we examined 10,047 primary THAs performed between 2009 and 2021 using the DA (6,592; 65.6%) or PL (3,455; 34.4%) approach. Postoperative femoral (FNP) and sciatic/peroneal nerve palsies (PNP) were identified. Incidence and time to recovery was calculated, and association between surgical and patient risk factors and nerve palsy were evaluated using Chi-square tests. Results: The overall rate of nerve palsy was 0.34% (34/10,047) and was lower with the DA approach (0.24%) than the PL approach (0.52%), P = .02. The rate of FNPs in the DA group (0.20%) was 4.3 times more than the rate of PNPs (0.05%), while in the PL group the rate of PNPs (0.46%) was 8 times more than that of FNPs (0.06%). Higher rates of nerve palsy were observed with women, shorter patients, and nonosteoarthritis preoperative diagnoses. Full recovery of motor strength occurred in 60% of cases with FNP and 58% of cases with PNP. Conclusion: Nerve palsy is rare after contemporary THA through the PL and DA approaches. The PL approach was associated with a higher rate of PNP, whereas the DA approach was associated with a higher rate of FNP. Femoral and sciatic/peroneal palsies had similar rates of complete recovery.