Anterior Smith-Petersen Approach to Hip

MRI based illustration of the direct anterior approach through the interval between sartorius and tensor fascia lata, exposing rectus femori
MRI based illustration of the direct anterior approach through the interval between sartorius and tensor fascia lata, exposing rectus femoris. The lateral femoral cutaneous nerve runs close to the interval and is at risk. Image from Munoz JP, Espinoza I, Figueroa S. Understanding Hip Surgical Approaches, A Review With Clinical and Imaging Correlation. Cureus. 2025, 17(6), e86724. CC BY 4.0.
Anterior Smith-Petersen Approach to Hip, muscles of the front of the thigh
Muscles of the front of the thigh. Image by Henry Vandyke Carter, Wikimedia Commons, Public domain.

Indications

  • True internervous approach to the anterior hip and ilium
  • Open reduction of developmental dysplasia of the hip
  • Drainage of septic arthritis
  • Femoral head fractures, especially anterior Pipkin fragments
  • Salter osteotomy, periacetabular osteotomy and iliac crest graft harvest
  • Hemiarthroplasty and total hip replacement, with DAA using the distal interval

Position

  • Supine with a small bolster under the ipsilateral buttock

Landmarks and Incision

  • Landmarks are the iliac crest and ASIS
  • Incision along the anterior half of the crest to the ASIS, then distally towards the lateral patella

Internervous Plane

  • Superficial plane between sartorius (femoral nerve) and TFL (superior gluteal nerve)
  • Deep plane between rectus femoris (femoral nerve) and gluteus medius (superior gluteal nerve)

Superficial Dissection

  • LFCN pierces the fascia near the ASIS and runs over sartorius, so incise fascia on the tensor side
  • Develop the sartorius and TFL interval
  • Proximally elevate gluteus medius and TFL subperiosteally from the outer table
  • Ligate the ascending branch of the lateral femoral circumflex artery

Deep Dissection

  • Detach rectus femoris direct head from the AIIS and reflected head from the superior rim
  • Retract rectus and iliopsoas medially and gluteus medius laterally
  • T-shaped capsulotomy
  • Anterior dislocation with external rotation and adduction

Direct anterior approach

  • Distal Hueter interval through a shorter incision, with no muscle detached from the pelvis
  • Incision distal and lateral to the ASIS over the TFL belly
  • TFL retracted laterally within its sheath, keeping the LFCN medial
  • Neck osteotomy in situ, with fluoroscopy for cup position and leg length
  • Femoral exposure needs extension, adduction, external rotation and posterosuperior capsular release
  • Muscle sparing with a low dislocation rate
  • LFCN neurapraxia, femoral fracture or perforation, and wound problems in obese groin folds

Structures at Risk

  • LFCN, causing meralgia paraesthetica
  • Femoral nerve, medial to the approach
  • Ascending branch of the lateral femoral circumflex artery

Extension

  • Proximally along the crest into the iliofemoral approach to both iliac tables
  • Distally into the anterolateral approach to the femoral shaft

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