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

Critical Pre-Procedure Determination

DHS plating should only be used for stable intertrochanteric fractures; unstable patterns, reverse obliquity fractures, and subtrochanteric extension require cephalomedullary nail fixation instead. 1, 2 Unstable patterns include comminuted fractures with posteromedial comminution, reverse obliquity patterns, and any subtrochanteric extension 2. Using DHS for unstable fractures, particularly in osteoporotic bone, results in failure rates exceeding 50% 3.

Preoperative Preparation

Patient Optimization (Pre-Incision)

• Do not apply preoperative traction - this has no benefit and is specifically contraindicated 1, 2
• Administer prophylactic antibiotics within one hour of skin incision to reduce surgical site infections 2
• Ensure adequate hydration with intravenous fluids, as most patients are hypovolemic 2
• Implement multimodal analgesia with preoperative peripheral nerve block 2
• Monitor depth of anesthesia with BIS monitoring to avoid cardiovascular depression in elderly patients 2

Anesthesia Selection

• Either spinal or general anesthesia is appropriate with no preference 1, 2
• Maintain systolic blood pressure within 20% of pre-induction values throughout surgery using vasopressors and/or fluids 1

Patient Positioning

• Position patient supine on fracture table with careful traction applied to affected limb
• Avoid excessive flexion and internal rotation of the non-operative hip to prevent pressure damage 2
• Ensure sympathetic positioning to prevent pressure sores and neuropraxia in elderly patients with fragile skin 2
• Implement active warming strategies intraoperatively to prevent hypothermia 2

Surgical Technique: Step-by-Step

Step 1: Incision and Exposure

• Make a lateral incision centered over the greater trochanter, extending distally along the femoral shaft (typically 8-12 cm)
• Incise fascia lata in line with skin incision
• Split vastus lateralis muscle fibers longitudinally or elevate anteriorly to expose lateral femoral cortex

Step 2: Fracture Reduction

• Achieve anatomic reduction under fluoroscopic guidance in both AP and lateral views
• Confirm restoration of medial cortical continuity and normal neck-shaft angle (approximately 130-135 degrees)
• Maintain reduction with temporary fixation if needed

Step 3: Guide Wire Placement

• Position the guide wire in the postero-inferior and central position within the femoral head and neck - this produces the highest percentage of good results, while anterior or superior positioning results in higher cut-out rates 4
• Insert guide wire through lateral cortex, aiming for center-center or slightly inferior position on AP view
• On lateral view, target central or slightly posterior position
• Advance wire to within 5-10 mm of subchondral bone of femoral head
• Confirm optimal positioning with fluoroscopy before proceeding

Step 4: Reaming and Lag Screw Insertion

• Ream over guide wire using triple reamer system to appropriate depth
• Measure lag screw length using depth gauge
• Insert lag screw over guide wire, ensuring it reaches within 5-10 mm of subchondral bone
• The distance of screw tip to subchondral bone has minimal influence on outcome, but central positioning is critical 4
• Remove guide wire after lag screw insertion

Step 5: Barrel-Plate Application

• Slide barrel-plate over lag screw
• Position plate flush against lateral femoral cortex
• Ensure plate is aligned with femoral shaft axis

Step 6: Plate Fixation

• Insert compression screw into barrel to engage lag screw
• Apply controlled compression (typically 1-2 turns after resistance met)
• Secure plate to femoral shaft with cortical screws (typically 4-6 screws)
• Insert screws in standard or locking fashion depending on bone quality
• Confirm all screws have bicortical purchase

Step 7: Final Verification

• Obtain final fluoroscopic images in AP and lateral views
• Confirm lag screw position remains postero-inferior and central 4
• Verify fracture reduction is maintained
• Ensure no screw penetration of femoral head
• Check that compression has been achieved at fracture site

Step 8: Closure

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

Critical Technical Pitfalls to Avoid

• Anterior or superior lag screw positioning produces higher incidence of cut-out 4 - always aim for postero-inferior and central placement
• Inadequate reduction before fixation leads to malunion and hardware failure
• Insufficient screw purchase in osteoporotic bone increases failure risk 3
• Over-compression can cause fracture comminution in osteoporotic bone

Postoperative Management

Immediate Post-Operative Care

• Continue active warming strategies to prevent hypothermia 2
• Administer fondaparinux or low molecular weight heparin for DVT prophylaxis 2
• Time low molecular weight heparin administration between 18:00-20:00 to minimize bleeding risk with neuraxial anesthesia 2

Pain Management

• Continue regular paracetamol throughout the perioperative period 2
• Use opioids cautiously, especially in patients with renal dysfunction, and avoid oral opioids in renal dysfunction 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

Mobilization and Weight-Bearing

• Allow immediate weight-bearing as tolerated 2
• Implement early mobilization protocols to reduce complications and improve outcomes 2
• Use sequential compression devices while hospitalized 2
• Continue pharmacologic prophylaxis for 4 weeks postoperatively 2

Transfusion Management

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

Long-Term Follow-Up

• Obtain outpatient DEXA scan and refer to bone health clinic for osteoporosis evaluation and treatment 2
• Monitor radiographically for signs of hardware failure, particularly in first 3-6 months

Important Contraindications and Alternative Considerations

DHS is not effective for pathologic fractures due to lack of bone healing, particularly with planned subsequent radiation 1. In pathologic fractures, consider alternative fixation methods or prosthetic replacement 1.

For unstable intertrochanteric fractures with osteoporosis, failure rates exceed 50% with DHS fixation 3. In these cases, cephalomedullary nail fixation is mandatory 1, 2.