Lateral cutaneous femoral nerve blockade-limited skin incision coverage in hip arthroplasty

This paper seeks to assess the potential use of blocking the lateral cutaneous femoral nerve (LCN) for patients undergoing hip surgery. In this study, ultrasound guidance was used to specifically block the LCN using a small volume of local anaesthetic in 20 healthy volunteer anaesthetists. An orthopaedic surgeon then drew lines on the volunteers reflecting three common cutaneous incision lines (anterolateral, lateral, and posterior approach) for hip arthroplasty using an ultraviolet reflecting pen invisible in normal lighting. The relationship between the anaesthesia produced by this block and the marked incision lines was then assessed. More than half (32 of 60) of the drawn incision lines fell completely outside of the anaesthesia produced by the LCN block. Of the remaining incision lines drawn, most were less than half covered by LCN blockade with only three lines more than 50% covered and none more than 75% covered. The skin anaesthesia produced by LCN blockade was usually anterior and inferior to the surgical lines marked. This significant lack of overlap between common hip arthroplasty incision lines and the anaesthesia produced by blockade of the lateral cutaneous femoral nerve draws into question the utility of this block for hip surgery.