Hip – Direct Anterior (Smith-Petersen)

Marking the bikini incision for the direct anterior approach, starting 2 cm distal and lateral to the anterior superior iliac spine and runn
Marking the bikini incision for the direct anterior approach, starting 2 cm distal and lateral to the anterior superior iliac spine and running parallel to the iliac crest. The subcutaneous layer is then mobilised to reach the usual interval. Image from Faldini C, Traina F, Pilla F, D’Agostino C, Brunello M, Morandi Guaitoli M, Di Martino A. For many but not for all, the bikini incision direct anterior approach for total hip arthroplasty. A narrative review. J Orthop Traumatol. 2024, 25(1), 66. CC BY 4.0.
Gray’s Anatomy illustration of the anterior thigh muscles
Muscles of the front of the thigh and iliac region. The direct anterior approach works through the interval between sartorius and tensor fasciae latae. Image by Henry Vandyke Carter, Gray’s Anatomy (1918), Wikimedia Commons, public domain.

Position

  • supine

Landmarks

Incision

  • Curved longitudinal incision
  • Runs along the anterior half of the iliac crest to the ASIS
  • Then vertically down anterior thigh for 8 cm

Internervous Plane

Superficial Dissection

  • Deepen the incision
  • Being careful to avoid damaging the Lateral Femoral cutaneous nerve of the thigh
  • ER leg to stretch Sartorius to make it more prominent
  • Identify the gap between TFL & sartorius
    • Develop this plane
    • Superiorly near the ASIS
      • Ascending Branch of Lateral femoral circumflex artery must be ligated

Deep Dissection

  • Identify Rectus femoris & Gluteus medius
  • Detach the Direct & Reflected heads of Rectus from its origins & retract it medially
  • Retract Gluteus medius laterally
  • Exposes hip joint capsule
  • Iliopsoas is often partly attached to inferior aspect of hip joint capsule & must be released from it
  • Adduct & IR leg to stretch & define capsule
  • T shaped capsular incision

Dangers

  • Nerves
    • Lateral femoral cutaneous nerve
    • Femoral nerve
  • Vessels
    • Ascending branch of lateral femoral circumflex artery

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.