What is the step-by-step procedure for bipolar hemiarthroplasty in treating a fracture of the intracapsular neck of the femur?

Bipolar Hemiarthroplasty Procedure for Intracapsular Femoral Neck Fracture

Bipolar hemiarthroplasty is the preferred surgical treatment for displaced intracapsular femoral neck fractures in elderly patients due to shorter operative time, lower dislocation risk, and acceptable functional outcomes compared to total hip arthroplasty. 1

Preoperative Planning

• Obtain standard radiographs: AP pelvis and lateral hip views 1
• Consider CT scan for better fracture characterization if needed
• Ensure surgery is performed within 24-48 hours of admission to reduce complications and mortality 1
• Select appropriate implant size based on preoperative templating
• Prepare for cemented femoral stem fixation (strongly recommended) 1

Anesthesia

• Either spinal or general anesthesia is appropriate (strong recommendation) 1
• Position patient in lateral decubitus position for posterior approach or supine for anterolateral approach

Surgical Approach

• Either anterolateral or posterior approach can be used (no preferred approach per guidelines) 1
• For posterior approach:
  • Make a curved incision centered over the greater trochanter
  • Incise fascia lata in line with skin incision
  • Split gluteus maximus fibers
  • Identify and protect sciatic nerve
  • Externally rotate the hip and identify short external rotators
  • Tag and detach piriformis, gemelli, and obturator internus tendons
  • Incise posterior capsule in a T-shaped manner

Femoral Head Resection

• Dislocate the hip by internal rotation, flexion, and adduction
• Identify the femoral neck fracture
• Perform femoral neck osteotomy at appropriate level (usually 1-2 cm above lesser trochanter)
• Remove the femoral head and inspect the acetabulum

Acetabular Preparation and Assessment

• Examine acetabulum for cartilage damage or pathology
• Remove any loose fragments or debris
• Measure the femoral head to determine appropriate prosthesis size

Femoral Canal Preparation

• Identify the femoral canal entry point
• Open the canal with a box chisel
• Use sequential reamers to prepare the canal
• Use broaches of increasing size until appropriate fit is achieved
• Perform trial reduction with provisional components to assess stability, leg length, and offset

Implantation

• Clean and dry the femoral canal thoroughly
• For cemented technique (strongly recommended) 1:
  • Insert cement restrictor
  • Prepare cement according to manufacturer's instructions
  • Inject cement in retrograde fashion
  • Insert the femoral stem with appropriate version (10-15° anteversion)
  • Maintain position until cement hardens
• Attach the appropriate size bipolar head to the femoral stem
• Reduce the hip by traction, internal rotation, and abduction

Closure

• Implement enhanced soft tissue repair with locking loop stitches to minimize dislocation risk 1
• Reattach the short external rotators and posterior capsule to the greater trochanter (for posterior approach)
• Close the fascia lata, subcutaneous tissue, and skin in layers
• Apply sterile dressing

Postoperative Care

• Begin physical therapy on postoperative day 1 1
• Implement appropriate pain management
• Provide antibiotic prophylaxis
• Correct postoperative anemia if present 2
• Monitor for and manage complications:
  • Dislocation (lower risk with bipolar compared to total hip arthroplasty) 3, 4
  • Infection
  • Deep vein thrombosis
  • Acetabular erosion (less common with bipolar compared to unipolar) 5, 6
• Progress from assisted to independent ambulation based on patient ability 1
• Follow-up at 2-4 weeks, then at 3 months, 6 months, and annually 1

Advantages of Bipolar Over Unipolar Hemiarthroplasty

• Better range of motion 5
• Less acetabular erosion 5, 6
• Lower dislocation rates compared to total hip arthroplasty 3, 4
• Comparable functional outcomes to total hip arthroplasty in elderly patients 3

Potential Complications and Management

• Dislocation: Closed reduction under anesthesia, possible revision if recurrent
• Infection: Antibiotics, possible debridement or revision
• Periprosthetic fracture: Internal fixation or revision based on fracture pattern
• Acetabular erosion: Less common with bipolar prosthesis compared to unipolar 5, 6

Clinical Pearls

• Ensure proper version of the femoral component (10-15° anteversion) to minimize dislocation risk
• Avoid excessive leg lengthening to prevent nerve injury and gait problems
• Cemented stems are strongly recommended over uncemented ones in elderly patients 1
• Early mobilization is crucial for optimal outcomes and reducing complications 2, 1