What is the step-by-step procedure for treating a fracture femur with Dynamic Hip Screw (DHS) plating?

Step-by-Step Procedure for Femur Fracture Fixation with Dynamic Hip Screw (DHS) Plating

The surgical fixation of femoral fractures using Dynamic Hip Screw (DHS) plating is a well-established technique that provides stable fixation for intertrochanteric fractures, allowing for early mobilization and improved patient outcomes. The procedure must be performed with careful attention to technical details to minimize complications and ensure optimal healing.

Preoperative Preparation

1. Patient Positioning:

   • Position patient supine on a fracture table
   • Apply traction to the affected limb to achieve fracture reduction
   • Ensure proper alignment with image intensifier verification
   • Avoid excessive flexion and internal rotation of the non-operative hip 1

2. Anesthesia Considerations:

   • Either spinal or general anesthesia is appropriate (strong recommendation) 1
   • Consider regional nerve blocks (femoral/fascia iliaca) for supplemental analgesia 1
   • Administer prophylactic antibiotics within one hour of skin incision 1

3. Thromboprophylaxis:

   • Apply thromboembolism stockings or intermittent compression devices 1
   • Administer low molecular weight heparin as per protocol (typically between 18:00-20:00 if surgery is planned for next day) 1

Surgical Procedure

1. Approach and Exposure

• Make a lateral incision starting 2-3 cm below the greater trochanter, extending distally 8-10 cm
• Incise the fascia lata in line with the skin incision
• Split the vastus lateralis muscle along its fibers to expose the lateral femoral shaft
• Identify the fracture site and lateral femoral cortex

2. Guide Wire Insertion

• Under fluoroscopic guidance, place the guide wire at the center of the femoral head in both AP and lateral views
• Position the guide wire in the center or slightly posterior-inferior position in the femoral head (avoid anterior or superior placement which increases cut-out risk) 2
• Ensure the guide wire is 1-2 cm from the subchondral bone

3. Reaming

• Measure the required length of the lag screw using the measuring device over the guide wire
• Ream over the guide wire to the appropriate diameter for the lag screw
• Take care not to penetrate the femoral head

4. Lag Screw Insertion

• Insert the DHS lag screw over the guide wire to the predetermined depth
• Position the screw tip ideally in the center or slightly posterior-inferior position of the femoral head 3
• Remove the guide wire after lag screw placement

5. Side Plate Application

• Select appropriate length side plate (for stable fractures, a two-hole side plate may be sufficient) 4
• Align the barrel of the side plate with the lag screw
• Tap the plate onto the lag screw until fully seated
• Secure the plate to the femoral shaft with bicortical screws

6. Additional Stabilization (for Unstable Fractures)

• For unstable or comminuted fractures, consider:
  • Additional screws to secure the greater trochanter
  • Trochanteric buttress plate to prevent lateralization of the greater trochanter 5
  • Cerclage wires for comminuted fragments

7. Final Assessment

• Obtain AP and lateral fluoroscopic images to confirm:
  • Proper reduction of the fracture
  • Correct position of the lag screw in the femoral head
  • Adequate fixation of the side plate to the femoral shaft
• Check for impingement or hardware prominence
• Ensure smooth sliding of the lag screw within the barrel

8. Wound Closure

• Irrigate the wound thoroughly
• Close the vastus lateralis and fascia lata with absorbable sutures
• Close subcutaneous tissue and skin in layers
• Apply sterile dressing

Postoperative Management

1. Pain Management:

   • Implement multimodal analgesia incorporating nerve blocks (strong recommendation) 1
   • Regular paracetamol administration
   • Judicious use of opioids, especially in patients with renal dysfunction 1

2. Mobilization:

   • Begin early mobilization, typically within 24 hours post-surgery
   • For stable fractures fixed with DHS, full weight bearing can be allowed immediately 4
   • For unstable fractures, weight bearing may be restricted based on fracture pattern and fixation quality

3. Thromboprophylaxis:

   • Continue mechanical and pharmacological thromboprophylaxis
   • Early mobilization helps reduce DVT risk 1

Common Pitfalls and Complications

1. Screw Cut-Out:

   • Most common mode of failure (16.7% in some studies) 2
   • Prevention: Ensure proper screw position (center or posterior-inferior) in the femoral head 3, 2
   • Avoid anterior or superior placement of the lag screw

2. Implant Failure:

   • Can occur at the barrel-plate junction or screw-barrel interface 6
   • More common in cases of non-union or unstable fracture patterns
   • Prevention: Proper fracture reduction and appropriate implant selection

3. Excessive Shortening:

   • Can occur in unstable fractures due to excessive sliding
   • Consider additional stabilization techniques for unstable patterns 5

4. Infection:

   • Prevention: Proper antibiotic prophylaxis, meticulous surgical technique
   • Early recognition and aggressive treatment if suspected

5. Malreduction:

   • Ensure anatomic reduction before implant placement
   • Verify reduction in both AP and lateral views

By following this systematic approach to DHS fixation of femoral fractures, surgeons can maximize the chances of successful outcomes while minimizing complications, allowing for early mobilization and improved functional recovery.