Pressure monitoring of the femoral nerve during total hip replacement: an explanation for iatropathic palsy.

Pressure changes around the femoral nerve were monitored throughout 10 consecutive primary total hip replacements to identify any surgical steps that might raise pressure around the nerve and be implicated in iatropathic palsy. The only notable variable was the patient himself/herself. The only step that consistently raised pressure around the nerve, sometimes to alarming levels, was use of a retractor sited on the anterior lip of the acetabulum. Pressure changes were modest in patients with an endomorphic body type suggesting relative protection from this injury by a thicker soft cushion.