What is the step-by-step procedure for bipolar hemiarthroplasty in an elderly patient with an intracapsular neck of femur fracture, considering their likely limited mobility and potential for osteoporosis?

Bipolar Hemiarthroplasty for Intracapsular Femoral Neck Fracture: Detailed Surgical Procedure

Preoperative Preparation

Bipolar hemiarthroplasty with a cemented femoral stem through a posterior approach is the recommended procedure for displaced intracapsular femoral neck fractures in elderly patients with limited mobility and osteoporosis. 1, 2

Patient Optimization

• Conduct DNAR discussions prior to surgery and ensure the anesthesiology team is informed of the outcome 2
• Correct reversible coagulopathy and optimize anticoagulation status before proceeding 2
• Administer prophylactic antibiotics within 60 minutes before skin incision 2
• Administer tranexamic acid at the start of surgery to reduce blood loss and transfusion requirements 1, 3

Anesthesia Selection

• Either spinal or general anesthesia is appropriate, with no superiority of one over the other 1, 3
• For regional anesthesia, blockade of the lateral cutaneous nerve of the thigh, femoral, obturator, sciatic, and lower subcostal nerves is required 2
• Administer multimodal analgesia incorporating a preoperative femoral nerve block for optimal pain control 1, 2, 3

Patient Positioning and Surgical Approach

Positioning

• Position the patient in lateral decubitus position with the affected hip uppermost 2
• Ensure all bony prominences are adequately padded to prevent pressure injuries 2
• Secure the patient to the operating table with appropriate supports 2

Posterior Approach Technique

• Make a posterolateral incision centered over the greater trochanter, extending proximally and distally along the femoral shaft 2
• Incise the fascia lata in line with the skin incision 2
• Split the gluteus maximus muscle fibers bluntly in line with their orientation 2
• Identify and protect the sciatic nerve throughout the procedure 2
• Perform a capsulotomy by incising the posterior hip capsule, preserving tissue for meticulous repair later to minimize dislocation risk 2

Femoral Head Removal and Canal Preparation

Fracture Exposure and Head Removal

• Externally rotate and flex the hip to deliver the femoral head into the surgical field 2
• Remove the femoral head and any remaining fracture fragments from the acetabulum 2
• Inspect the acetabular cartilage for any damage 2

Femoral Neck Osteotomy

• Perform femoral neck osteotomy at the base of the femoral neck using an oscillating saw 2
• Remove the remaining femoral neck fragment 2
• Ensure the osteotomy level allows for appropriate prosthetic positioning and leg length restoration 2

Canal Preparation

• Open the femoral canal using a box chisel or awl at the piriformis fossa 2
• Use sequential reamers or broaches to prepare the femoral canal, starting with smaller sizes and progressively increasing 2
• Continue reaming until cortical bone contact is achieved and the canal is prepared to accept the final stem size 2
• Irrigate the canal thoroughly to remove bone debris and fat 2

Cemented Stem Insertion

Use cemented femoral stems in all elderly patients with osteoporosis, as this is strongly recommended to improve hip function, reduce residual pain, and decrease periprosthetic fracture risk. 1, 3

Cement Preparation and Application

• Prepare bone cement according to manufacturer specifications 1
• Use pulsatile lavage to clean and dry the femoral canal 2
• Insert a cement restrictor 2-3 cm beyond the tip of the planned stem 2
• Apply cement in a retrograde fashion using a cement gun to ensure complete canal filling 2
• Pressurize the cement using a pressurizer to achieve optimal cement-bone interdigitation 2

Stem Insertion

• Insert the final femoral stem with 5-10 degrees of anteversion while the cement is still in the doughy phase 2
• Maintain stem position and alignment until the cement fully polymerizes 2
• Remove excess cement from around the prosthesis 2

Bipolar Prosthesis Assembly and Reduction

Component Assembly

• Assemble the bipolar prosthesis by placing the appropriate-sized bipolar head onto the femoral stem 2
• Select head size based on the removed femoral head size and acetabular dimensions 2
• Ensure the bipolar head is securely locked onto the stem taper 2

Hip Reduction

• Reduce the hip joint by flexing, internally rotating, and applying axial traction 2
• Confirm stable reduction through full range of motion testing 2
• Verify leg lengths are equal by comparing knee heights with hips and knees extended 2

Capsular Repair

• Perform meticulous capsular repair to minimize dislocation risk 2, 4
• Reattach the short external rotators to their anatomic insertion sites 2
• Close the fascia lata and subcutaneous tissues in layers 2

Immediate Postoperative Management

Pain Control

• Continue multimodal analgesia with regular paracetamol throughout the perioperative period 2
• Use opioids cautiously, especially in patients with renal dysfunction 2
• Avoid codeine due to constipation, emesis, and association with postoperative cognitive dysfunction 2
• Avoid NSAIDs in patients with renal dysfunction 2

Thromboprophylaxis

• Administer fondaparinux or low molecular weight heparin for DVT prophylaxis 2
• Continue thromboprophylaxis according to institutional protocols 3

Early Mobilization

• Implement early mobilization protocols with weight-bearing as tolerated on postoperative day one if medically stable 2, 3
• Begin physical therapy immediately to reduce DVT risk and improve functional recovery 2
• Allow full weight-bearing immediately, as the cemented stem provides immediate stability 2

Postoperative Monitoring and Complications

Routine Monitoring

• Continue active warming strategies to prevent hypothermia 2
• Perform routine systems examinations and regular assessment of cognitive function 2
• Monitor for pressure sores, nutritional status, and renal function 2

Transfusion Management

• Use a transfusion threshold no higher than 8 g/dL in asymptomatic patients 2
• Consider transfusion for symptomatic anemia 2

Interdisciplinary Care

• Utilize interdisciplinary care programs involving orthopedics, geriatrics, physical therapy, and nursing to decrease complications and improve outcomes 1, 3

Long-Term Follow-Up

Osteoporosis Management

• Arrange outpatient DEXA scan and referral to bone health clinic for osteoporosis evaluation and treatment 2
• Initiate anti-osteoporotic medication to prevent subsequent fractures 1

Functional Outcomes

• Bipolar hemiarthroplasty provides good functional outcomes with Harris Hip Scores typically ranging from 86-96 at one year 5, 6
• Complication rates are low, with dislocation rates, mortality, and blood loss comparing favorably to other arthroplasty options 7