What is the step by step procedure for bipolar hemiarthroplasty in a patient with an intracapsular neck of femur fracture?

Bipolar Hemiarthroplasty for Intracapsular Neck of Femur Fracture: Step-by-Step Surgical Procedure

For displaced intracapsular femoral neck fractures in elderly patients, bipolar hemiarthroplasty with a cemented femoral stem is the recommended surgical treatment, performed through a posterior approach with meticulous capsular repair to minimize dislocation risk. 1

Preoperative Preparation

Anesthesia Selection

• Either spinal or general anesthesia is appropriate with no superiority of one over the other, though spinal anesthesia may reduce postoperative confusion in elderly patients 1, 2
• Administer multimodal analgesia incorporating a preoperative nerve block (femoral nerve block) in the emergency department or preoperatively to optimize pain control 1, 3

Pharmacologic Interventions

• Administer prophylactic antibiotics within one hour of skin incision to reduce surgical site infections 3, 2
• Administer tranexamic acid at the start of the procedure to reduce blood loss and transfusion requirements 1, 3, 2
• Ensure adequate preoperative intravenous fluid resuscitation, as many elderly patients are hypovolemic 3

Timing and Patient Optimization

• Perform surgery within 24-48 hours of admission for optimal outcomes 3, 2
• Do not use preoperative traction as it provides no benefit 3

Patient Positioning

• Position the patient in lateral decubitus position with the affected hip uppermost 2
• Meticulously pad all bony prominences to prevent pressure injuries, particularly critical in elderly patients with fragile skin 3, 2
• Avoid excessive flexion and internal rotation of the non-operative hip to prevent pressure damage 3
• Implement active warming strategies intraoperatively to prevent hypothermia 3

Surgical Approach

Posterior Approach Technique

• Make a posterior 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 in the direction of its fibers to minimize muscle damage 2
• Identify and protect the sciatic nerve throughout the procedure to prevent nerve injury 2

Capsular Exposure

• Perform a T-shaped incision over the posterior hip capsule for optimal exposure 4
• Tag the short external rotators (piriformis, obturator internus, gemelli) with sutures for later repair 4
• Detach the short external rotators from their insertion on the greater trochanter 2

Femoral Neck Osteotomy

• Dislocate the femoral head posteriorly by flexion, adduction, and internal rotation of the hip 2
• Perform femoral neck osteotomy at the base of the femoral neck using an oscillating saw 2
• Remove the femoral head and any remaining neck fragments 2
• Clear the acetabulum of any fracture debris or loose cartilage 2

Femoral Canal Preparation

• Expose the femoral canal and remove any fracture debris to ensure proper implant placement 2
• Use sequential reamers or broaches to prepare the femoral canal, starting with smaller sizes and progressively increasing 2
• Achieve appropriate canal preparation for the selected stem size, ensuring adequate cortical contact 2

Trial Reduction

• Insert trial femoral stem and bipolar head components 2
• Perform trial reduction to assess hip stability, leg length, offset, and range of motion 2
• Confirm appropriate component sizing before final implantation 2

Cemented Stem Implantation

Cemented femoral stems are strongly recommended over uncemented stems as they improve hip function and reduce residual pain postoperatively 1, 2

Cement Technique

• Thoroughly clean and dry the femoral canal using pulsatile lavage and suction 2
• Insert a cement restrictor at the appropriate depth (typically 1-2 cm beyond the tip of the planned stem) 2
• Mix bone cement according to manufacturer specifications 2
• Apply cement in a retrograde fashion using a cement gun to ensure complete canal filling 2
• Insert the final femoral stem with 5-10 degrees of anteversion 2
• Hold the stem in the correct position with steady pressure until the cement hardens completely 2
• Remove excess cement before complete polymerization 2

Bipolar Head Assembly

• Assemble the bipolar prosthesis by placing the appropriate-sized bipolar head onto the femoral stem 2
• Ensure secure seating of the bipolar component on the Morse taper 2
• Properly tension the abductor mechanism to ensure stability and prevent dislocation 2

Hip Reduction and Stability Assessment

• Reduce the hip by gentle traction and internal rotation 2
• Test range of motion in all planes, particularly flexion, adduction, and internal rotation 2
• Assess stability to ensure no impingement or tendency toward dislocation 2
• Confirm appropriate leg length and offset compared to the contralateral side 2

Capsular and Soft Tissue Repair

Meticulous capsular repair is critical to reduce dislocation risk 4

• Repair the posterior capsule and short external rotators using suture anchors placed in the greater trochanter 4
• This capsular-enhanced repair technique significantly reduces postoperative dislocation rates 4
• Ensure robust repair with non-absorbable or heavy absorbable sutures 4
• Repair the gluteus maximus fascia 2

Wound Closure

• Close the fascia lata with absorbable sutures 2
• Close subcutaneous tissue in layers 2
• Close skin with staples or sutures 2
• Apply sterile dressing 2

Postoperative Management

Immediate Postoperative Care

• Continue active warming strategies to prevent hypothermia 3
• Administer regular paracetamol throughout the perioperative period to reduce pain and inflammation 3
• Use opioids cautiously, especially in patients with renal dysfunction; avoid codeine due to constipation, emesis, and association with postoperative cognitive dysfunction 3
• Avoid NSAIDs in patients with renal dysfunction 3

Thromboprophylaxis

• Administer fondaparinux or low molecular weight heparin for DVT prophylaxis 1, 3, 2
• Use sequential compression devices while hospitalized 3
• Continue pharmacologic prophylaxis for 4 weeks postoperatively 3
• Time low molecular weight heparin administration between 18:00-20:00 to minimize bleeding risk with neuraxial anesthesia 3

Mobilization

• Implement early mobilization protocols with weight-bearing as tolerated to reduce complications and improve outcomes 3
• Begin physical therapy on postoperative day one if medically stable 3

Transfusion Management

• Consider transfusion for symptomatic anemia 3
• Use a transfusion threshold no higher than 8 g/dL in asymptomatic patients 3

Long-term Follow-up

• Arrange outpatient DEXA scan and referral to bone health clinic for osteoporosis evaluation and treatment 3
• Utilize interdisciplinary care programs to decrease complications and improve outcomes 1

Key Technical Considerations and Pitfalls

Surgical Approach Selection

• The direct superior approach (DSA) demonstrates lower complication rates compared to anterolateral minimally invasive approach (ALMIS), though operative time is slightly longer 5
• Both approaches are acceptable, but DSA may be preferred when minimizing complications is the priority 5

Operative Time and Surgeon Experience

• Average operative time is 65-78 minutes for experienced surgeons 6, 5, 4
• Junior surgeons have longer operative times (77 vs 61 minutes) but similar complication rates to senior surgeons 6
• Nighttime surgery is associated with higher complication rates (11% vs 7%); perform non-urgent cases during daytime hours 6

Complication Prevention

• Zero dislocation rate is achievable with proper capsular repair using suture anchor technique 4
• Meticulous sterile technique and appropriate perioperative antibiotics are crucial to prevent infection 2
• Overall complication rate should be approximately 7.5%, with infections (3.1%), hematomas (1.7%), and dislocations (1.1%) being most common 6

Bipolar vs Unipolar Consideration

• Bipolar and unipolar hemiarthroplasty are equally beneficial according to AAOS guidelines 1
• However, bipolar prostheses demonstrate better Harris hip scores, range of motion, and fewer complications (particularly acetabular erosion and painful hip) in research studies 7