What is the step by step procedure for Bipolar Hemiarthroplasty by Watson Jones approach?

Bipolar Hemiarthroplasty by Watson Jones Approach: Step-by-Step Procedure

The Watson Jones approach for bipolar hemiarthroplasty is a viable anterolateral approach that provides adequate exposure while minimizing the risk of postoperative dislocation compared to posterior approaches. While specific guidelines for the Watson Jones approach are limited, the procedure follows established principles for hip hemiarthroplasty with particular attention to proper positioning, soft tissue handling, and cementation technique.

Preoperative Planning

• Ensure surgery is performed within 24-48 hours of admission to reduce complications and mortality 1
• Either spinal or general anesthesia is appropriate (strong recommendation) 2, 1
• Obtain standard radiographs of the affected hip
• Ensure adequate hydration before induction of anesthesia 1
• Prepare for potential bone cement implantation syndrome (BCIS) if using cemented technique 1
• Select appropriate implant size based on templating

Patient Positioning and Preparation

• Position patient in lateral decubitus position with affected side up
• Secure patient to the operating table with appropriate supports
• Prepare and drape the surgical site using standard aseptic technique
• Mark anatomical landmarks including greater trochanter, anterior superior iliac spine, and lateral border of patella

Surgical Approach (Watson Jones)

1. Make a straight lateral incision starting 2-3 cm posterior to the anterior superior iliac spine and extending distally over the greater trochanter for approximately 10-12 cm
2. Incise the fascia lata in line with the skin incision
3. Identify the interval between the tensor fasciae latae anteriorly and gluteus medius posteriorly
4. Develop this interval proximally and distally
5. Retract the tensor fasciae latae anteriorly and the gluteus medius posteriorly
6. Identify and protect the superior gluteal nerve
7. Incise the anterior joint capsule in a T-shaped manner
8. Expose the femoral neck and head

Femoral Head Resection and Preparation

1. Identify the level of femoral neck cut using preoperative templating
2. Perform the femoral neck osteotomy at the appropriate level
3. Remove the femoral head using a corkscrew extractor
4. Inspect the acetabulum for damage or pathology
5. Measure the femoral head to determine appropriate prosthesis size

Femoral Canal Preparation

1. Communicate with the anesthesia team before preparing the femoral canal for cement and prosthesis insertion 2, 1
2. Position the leg in adduction and external rotation to expose the proximal femur
3. Open the femoral canal with a box chisel at the piriformis fossa
4. Sequentially ream the femoral canal to the appropriate size
5. Use a broach to shape the proximal femur to match the prosthesis
6. Thoroughly wash and dry the femoral canal using a pressurized lavage system to clean the endosteal bone of fat and marrow contents 2, 1

Cement Application (Recommended)

1. Insert a distal suction catheter on top of an intramedullary plug 2, 1
2. Mix the bone cement according to manufacturer's instructions
3. Apply cement in retrograde fashion using the cement gun 2, 1
4. Pull the catheter out as soon as it is blocked with cement 2
5. Avoid excessive manual pressurization in high-risk patients 2, 1
6. Monitor the patient closely for signs of BCIS during cement application

Prosthesis Insertion

1. Insert the femoral stem into the cement at the appropriate version (typically 10-15° of anteversion)
2. Hold the stem in position until the cement hardens
3. Remove any excess cement
4. Select the appropriate bipolar head size
5. Perform a trial reduction to assess stability and leg length
6. Assemble the final bipolar head component
7. Impact the bipolar head onto the femoral neck

Reduction and Closure

1. Reduce the hip joint by gentle traction and internal rotation
2. Check stability through a range of motion
3. Irrigate the wound thoroughly
4. Repair the anterior capsule with strong sutures
5. Close the fascia lata with interrupted sutures
6. Close subcutaneous tissue and skin in layers

Postoperative Management

• Maintain vigilance for signs of cardiorespiratory compromise 2, 1
• Use either an arterial line or non-invasive automated blood pressure monitoring during/shortly after cement application 2
• Maintain systolic blood pressure within 20% of pre-induction values 2
• Have vasopressors ready in case of cardiovascular collapse 2, 1
• Begin physical therapy on postoperative day 1 1
• Implement an interdisciplinary care program to improve outcomes 2, 1

Important Considerations

• Cemented femoral stems are strongly recommended for bipolar hemiarthroplasty 2, 1
• Either unipolar or bipolar hemiarthroplasty can be equally beneficial (moderate recommendation) 2, 1
• The Watson Jones approach may offer a lower dislocation rate compared to posterior approaches 3
• Enhanced soft tissue repair with locking loop stitches can minimize dislocation risk 1
• Be aware that bipolar implants have shown a higher risk of reoperation compared to unipolar implants (HR = 1.3) 4

The Watson Jones approach provides adequate exposure while preserving the posterior soft tissue structures, which may contribute to enhanced stability following bipolar hemiarthroplasty for femoral neck fractures.