What is the step-by-step procedure for a total hip replacement using the posterior approach?

Step-by-Step Procedure for Total Hip Replacement: Posterior Approach

The posterior approach is a commonly used surgical technique for total hip replacement with excellent outcomes, though surgical technique should depend on surgeon and patient preference as there is inconclusive evidence for choosing a specific approach based on postoperative pain outcomes. 1

Patient Positioning and Preparation

1. Position the patient in lateral decubitus position with the affected hip facing upward
2. Secure the patient with anterior and posterior supports to stabilize the pelvis
3. Prepare and drape the surgical site using standard aseptic technique
4. Mark anatomical landmarks including the greater trochanter, iliac crest, and planned incision line

Surgical Incision and Approach

1. Make an 8-10 cm incision at a 60° oblique angle starting from the posterior-proximal corner of the greater trochanter 2
2. Incise only the gluteus maximus fascia, preserving the iliotibial band
3. Split the gluteus maximus muscle bluntly to expose the gluteus medius muscle, piriformis tendon, and triceps coxae (obturator internus and gemellus muscles)
4. Release and tag the piriformis and conjoined tendon from the greater trochanter
5. Elevate the gluteus minimus to expose the posterior hip capsule
6. Perform a T-shaped or rectangular capsulotomy of the posterior hip capsule

Hip Dislocation and Femoral Neck Resection

1. Dislocate the hip by flexing, adducting, and internally rotating the femur with axial compression
2. Identify the femoral neck and perform osteotomy at the planned level using an oscillating saw
3. Remove the femoral head
4. Protect the sciatic nerve throughout the procedure, as it runs posterior to the hip joint

Acetabular Preparation and Implantation

1. Place retractors to expose the acetabulum
2. Remove any remaining labrum and osteophytes
3. Ream the acetabulum sequentially to the appropriate size
4. Confirm proper size, position, and orientation (typically 40-45° abduction and 15-20° anteversion)
5. Impact the definitive acetabular component
6. Insert the appropriate liner (polyethylene, ceramic, or metal)

Femoral Preparation and Implantation

1. Position the leg for femoral canal preparation (flexed, adducted, and internally rotated)
2. Identify the entry point to the femoral canal
3. Open the canal with a box chisel or starter reamer
4. Sequentially ream and/or broach the femoral canal to the appropriate size
5. Perform trial reduction with provisional components to assess stability, range of motion, and leg length
6. After confirming appropriate sizing and positioning, implant the definitive femoral component
7. Attach the appropriate femoral head component

Final Assessment and Closure

1. Perform final reduction of the hip joint
2. Assess stability through range of motion testing, particularly in positions of risk (flexion, adduction, and internal rotation)
3. Verify appropriate leg length and offset
4. Perform meticulous repair of the posterior capsule, piriformis, and obturator internus tendons 2
5. Close the fascia, subcutaneous tissue, and skin in layers

Postoperative Management

1. Implement multimodal pain management including:

   • Paracetamol and NSAIDs/COX-2 inhibitors as baseline therapy 1, 3
   • Consider fascia iliaca block or local infiltration analgesia 1
   • Reserve opioids for rescue analgesia 1

2. Begin early mobilization and physical therapy on postoperative day 0-1 3

3. Focus on weight-bearing exercises and hip abductor strengthening 3

Important Considerations and Pitfalls

• Component Positioning: Improper positioning can lead to impingement, dislocation, and instability 3
• Soft Tissue Repair: Meticulous posterior capsular and external rotator repair is critical to reduce dislocation risk 2
• Nerve Protection: The sciatic nerve is at risk during posterior approach and must be protected throughout
• Leg Length Discrepancy: Careful assessment and correction of leg length is essential for patient satisfaction
• Dislocation Risk: The posterior approach traditionally has higher dislocation rates, though this has been mitigated with modern techniques including larger femoral heads and improved soft tissue repair 4

While the posterior approach has been associated with slightly higher dislocation rates historically, it offers excellent exposure, lower overall complication rates, and can be easily extended if needed 4. The direct anterior approach may offer slightly better early recovery in the first 2-4 weeks, but outcomes between approaches tend to equalize by 6 weeks postoperatively 4.