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.