What is the step-by-step procedure for treating an intertrochanteric femur fracture using Dynamic Hip Screw (DHS) plating?

Dynamic Hip Screw (DHS) Plating for Intertrochanteric Femur Fracture: Step-by-Step Procedure

DHS plating is the standard surgical treatment for stable intertrochanteric femur fractures, allowing for stable fixation and early mobilization to reduce morbidity and mortality. 1

Critical Pre-Procedure Assessment

DHS should only be used for stable intertrochanteric fractures (AO/OTA 31-A1 and 31-A2); unstable patterns including comminuted fractures, reverse obliquity patterns, subtrochanteric extension, and fractures with posteromedial comminution require cephalomedullary nail fixation instead. 2

• Verify fracture stability on AP and lateral radiographs before proceeding with DHS 2
• Do not use preoperative traction as it provides no benefit 2
• DHS is contraindicated for pathologic fractures due to lack of bone healing, particularly with planned subsequent radiation 2

Preoperative Preparation

• Administer prophylactic antibiotics within one hour of skin incision to reduce infection risk 1, 2
• Perform multimodal analgesia including peripheral nerve block in the emergency department or preoperatively 2
• Use either spinal/epidural or general anesthesia with consideration of peripheral nerve blocks for postoperative pain management 1
• Monitor depth of anesthesia with BIS monitoring to avoid cardiovascular depression, particularly in elderly patients 2
• Administer preoperative intravenous fluids routinely as many patients are hypovolemic, using cardiac output-guided fluid administration 2
• Implement active warming strategies intraoperatively and continue postoperatively to prevent hypothermia 1, 2
• Position patient supine on fracture table with careful attention to avoid excessive flexion and internal rotation of the non-operative hip to prevent pressure damage 2

Surgical Technique: Step-by-Step

Step 1: Patient Positioning and Draping

• Position patient supine on fracture table with perineal post 2
• Apply gentle longitudinal traction to affected limb 2
• Ensure sympathetic positioning to prevent pressure sores and neuropraxia in elderly patients with fragile skin 2

Step 2: Fracture Reduction

Achieving anatomic reduction under fluoroscopic guidance in both AP and lateral views is essential, with restoration of medial cortical continuity and normal neck-shaft angle (approximately 130-135 degrees). 2

• Verify reduction quality in both planes before proceeding 2
• Inadequate reduction before fixation leads to malunion and hardware failure 2
• Maintain systolic blood pressure within 20% of pre-induction values throughout surgery using vasopressors and/or fluids 2

Step 3: Lateral Approach and Exposure

• Make lateral incision centered over greater trochanter, extending distally along femoral shaft 2
• Incise fascia lata in line with skin incision 2
• Retract vastus lateralis anteriorly to expose lateral femoral cortex 2

Step 4: Guide Wire Placement

• Insert guide wire under fluoroscopic guidance aiming for center-center or slightly inferior position in femoral head on both AP and lateral views 2, 3
• Position screw in postero-inferior and central position in the femoral neck and head, as anterior or superior position produces higher incidence of cut-out. 3
• Advance guide wire to within 5-10 mm of subchondral bone 2
• Verify tip-apex distance will be less than 25 mm (optimal is approximately 14 mm) 4

Step 5: Reaming and Lag Screw Insertion

• Ream over guide wire using triple reamer system to appropriate depth based on measured lag screw length 2
• Insert lag screw over guide wire, ensuring it reaches within 5-10 mm of subchondral bone 2
• Verify final screw position on fluoroscopy before removing guide wire 2

Step 6: Barrel-Plate Application

• Slide barrel-plate over lag screw 2
• Position plate flush against lateral femoral cortex 2
• Ensure plate is aligned with femoral shaft axis to prevent varus deformity 2
• For stable fractures, a two-hole side plate is sufficient and less invasive than the traditional four-hole plate. 5

Step 7: Plate Fixation

• Secure plate to femoral shaft with cortical screws (typically 4-6 screws for four-hole plate, or 2 screws for two-hole plate) 2, 5
• Achieve bicortical purchase with all screws 2
• Avoid over-compression as this can cause fracture comminution in osteoporotic bone 2
• Ensure proper fixation of lesser trochanter and posteromedial bone fragment if present 6

Step 8: Final Verification

• Obtain final fluoroscopic images in AP and lateral views 2
• Verify lag screw position, plate alignment, and fracture reduction 2
• Confirm no penetration of femoral head by screw 6

Step 9: Wound Closure

• Irrigate wound copiously 6
• Close fascia lata, subcutaneous tissue, and skin in layers 6
• Apply sterile dressing 6

Critical Technical Pitfalls to Avoid

• Inadequate reduction before fixation leads to malunion and hardware failure 2
• Over-compression causes fracture comminution in osteoporotic bone 2
• Poor screw position (anterior or superior) results in higher cut-out rates 3
• Tip-apex distance greater than 25 mm increases risk of screw cut-out 4
• Nonstandard operative procedure and unsatisfactory reduction are major causes of complications 6
• Too early weight bearing without adequate fixation leads to failure 6

Postoperative Management

• Implement immediate weight-bearing as tolerated 2
• Continue appropriate thromboprophylaxis with fondaparinux or low molecular weight heparin for 4 weeks postoperatively 1, 2
• Time low molecular weight heparin administration between 18:00-20:00 to minimize bleeding risk with neuraxial anesthesia 2
• Use sequential compression devices while hospitalized 2
• Provide adequate pain management with regular paracetamol throughout the perioperative period 1, 2
• Use opioids cautiously, especially in patients with renal dysfunction, and avoid oral opioids in renal dysfunction 1, 2
• Do not administer codeine due to constipation, emesis, and association with postoperative cognitive dysfunction 2
• Use NSAIDs with extreme caution and avoid in renal dysfunction 2
• Implement early mobilization protocols to reduce complications 1, 2
• Consider transfusion for symptomatic anemia, using a transfusion threshold no higher than 8 g/dL in asymptomatic patients 2
• Arrange outpatient DEXA scan and referral to bone health clinic for osteoporosis evaluation and treatment 2

Expected Complications and Management

• Proximal femoral cortex fracture during insertion (2-3% incidence) 6
• Screw cut-out through femoral head (10-17% incidence with poor technique) 6, 3
• Varus deformity of hip (up to 8% incidence) 6
• Wound infection (approximately 5% incidence) 6
• Femoral head necrosis (rare, approximately 2% incidence) 6
• Stable fracture patterns with proper screw positioning produce high percentage of good results 3