The Anatomical Course of the Lateral Femoral Cutaneous Nerve in Relation to Various Skin Incisions Used for Primary and Revision Total Hip Arthroplasty With the Direct Anterior Approach.

Background: Although the direct anterior approach (DAA) has become a standard for primary and revision total hip arthroplasty, it involves a high risk of injuring the lateral femoral cutaneous nerve (LFCN). The aim of this study is to examine the course of the LFCN in relation to various skin incisions and approach extensions used for the DAA.
Methods: We obtained 44 limbs and hemipelves from 22 formalin-preserved cadavers, in which LFCN was identified. All nerve branches of the LFCN were carefully traced. The branching pattern and the distribution in the thigh were described in relation to the standard approach for primary total hip arthroplasty, the skin crease bikini incision, the longitudinal extension, and the lazy S extension of the DAA.
Results: We found 31 (70.5%) Sartorius-type, 6 (13.6%) posterior-type, and 7 (15.9%) fan-type branching patterns of the LFCN. We observed 2.02 branches per hemipelvis. All fan-type LFCNs had 3 or more than 3 branches. We found that the main branch of the LFCN was medial to the primary DAA approach as well as to the lazy S extended DAA approach. The bikini incision and the incision for the longitudinal extension of the DAA crosses the main branch of the LFCN in 100% of cases.
Conclusion: The fan-type pattern of the LFCN might be harmed by all skin incisions. Chances are high that LFCN branches could be jeopardized with a bikini-type incision and the longitudinal extension of the DAA. The risk of jeopardizing the LFCN with a lazy S-type distal extension is reduced.
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