Anterolateral Approach to Hip Joint (Watson-Jones) indications:
- Anterolateral approach to hip joint (Watson-Jones approach) combines an excellent exposure of the acetabulum with safety during reaming of the femoral shaft in total hip arthroplasty. It was popularized by Watson-Jones 1981.
Anterolateral approach to hip joint is used for:
- Total hip arthroplasty THR:
- Minimally invasive approach does not improve post-op gait kinematics when compared to traditional trans-gluteal approach.
- Patient at high risk for dislocation may benefit from antero-lateral approach since no posterior soft tissue disruption.
- Some concern that this approach can weaken the abductor and cause limping.
- Open reduction internal fixation of femoral neck fracture.
- Synovial biopsy of hip.
- Biopsy of femoral neck.
Position of the Patient
- Generally anterolateral approach to hip joint is performed in the lateral decubitus position.
- Or in the supine position, with the patient’s buttock close to the edge of the table to let fat fall away from incision.
Landmarks and Incision
- Anterior superior iliac spine.
- Greater trochanter.
- Shaft of the femur.
- Vastus lateralis ridge.
- Make incision starting 2.5 cm posterior and distal to anterior superior iliac spine ASIS.
- As it runs distal, it becomes centered over the tip of the greater trochanter, and Crosses posterior 1/3 of trochanter before running down the shaft of the femur.
- There is no true internervous plane for anterolateral approach to hip joint, since the gluteus medius muscle and the tensor fasciae latae have a common nerve supply, the superior gluteal nerve.
- Incise fat in line with incision and clear fascia lata.
- Incise fascia:
- Incise in direction of fibers, this will be more anterior as your dissect proximal.
- Incise at the posterior border of the greater trochanter.
- Develop interval between tensor fasciae latae and gluteus medius muslces:
- There will be a small series of vessels in this interval.
- Externally rotate the hip to put the capsule on stretch.
- Identify origin of vastus lateralis muscle.
- Detach abductor mechanism by one of two mechanisms:
- Trochanteric osteotomy: distal osteotomy site is just proximal to vastus lateralis ridge.
- Partial detachment of abductor mechanism: place a stay suture to prevent muscle split and damage to superior gluteal nerve (Nerve is 5 cm proximal to the acetabular rim).
- Expose anterior joint capsule.
- Detach reflected head of rectus femoris from the joint capsule to expose the anterior rim of the acetabulum:
- Easier with leg flexed slightly.
- Elevate part of the psoas tendon from the capsule.
- Perform anterior capsulotomy.
- Distal Extension of the Anterolateral approach to hip joint:
- Extend the skin incision down the lateral aspect of the thigh, and incise the deep fascia in line with the skin incision.
- Split the vastus lateralis to gain access to the lateral aspect of the femur. In this way, you can usefully extend the approach to include the entire length of the femur.
- Distal extension is often needed when the approach is used for open reduction and internal fixation of fractures of the femoral neck .
- Proximal Extension:
- The Anterolateral approach to hip joint cannot usefully be extended proximally.
- The structures at risk during anterolateral approach to hip joint includes:
- Femoral nerve:
- Most common problem is compression neuropraxia caused by medial retraction.
- Direct injury can occur from placing retractor into the psoas muscle.
- Femoral artery and vein:
- Can be damaged by retractors that penetrate the psoas.
- Confirm that anterior retractor is directly on bone.
- Abductor muscles of the hip:
- Caused by trochanteric osteotomy and/or disruption of abduction mechanism.
- Caused by denervation of the tensor fasciae by aggressive muscle split.
- Femoral shaft fractures:
- Usually occurs during dislocation (be sure to perform and adequate capsulotomy).
- Femoral nerve:
- Surgical Exposures in Orthopaedics book – 4th Edition
- Campbel’s Operative Orthopaedics book 12th