Femoral Nerve Palsy Following Total Hip Arthroplasty: Incidence and Course of Recovery.

BACKGROUND: Femoral nerve palsy (FNP) is a relatively uncommon complication following total hip arthroplasty (THA). There is little recent literature regarding the incidence of FNP and the natural course of recovery.

METHODS: Using our institutional database, we identified postoperative FNPs from 17,350 consecutive primary THAs performed from 2011 to 2016. Hip exposures were performed using a direct lateral (modified Hardinge), direct anterior (Smith-Peterson), anterolateral (Watson-Jones), or posterolateral (Southern or Moore) approach. Patients with FNP were contacted to provide a subjective assessment of convalescence and underwent objective muscle testing to determine the extent of motor recovery.

RESULTS: The overall incidence of FNP was 0.21% after THA, with the incidence 14.8-fold higher in patients undergoing anterior hip surgery using either a direct anterior (0.40%) or anterolateral (0.64%) approach. Significant recovery from FNP did not commence for a majority of patients until greater than 6 months postoperatively. Motor weakness had resolved in 75% of patients at 33.3 months, with remaining patients suffering from mild residual weakness that typically did not necessitate an assistive walking device or a knee brace. Nearly all patients had improved sensory manifestations, but such symptoms had completely resolved in less than 20% of patients.

CONCLUSION: FNP after hip surgery remains relatively uncommon, but may increase with a growing interest in anterior THA exposures. A near complete recovery with only mild motor deficits can be expected for a majority of patients in less than 2 years, although sensory symptoms may persist.