Reduction dislocation THA

Closed and Open Reduction of Dislocated Total Hip Arthroplasty (THA)

1. Indications

Reduction of a dislocated THA is indicated in the following scenarios:

• Acute dislocation of a primary or revision total hip arthroplasty.
• First-time dislocation with no significant component malpositioning.
• Recurrent dislocations in cases where component revision is not immediately feasible.
• Posterior or anterior dislocations that have been confirmed via imaging (X-ray or CT).
• Patient is hemodynamically stable and shows no signs of periprosthetic fracture.

2. Contraindications

• Unrecognized periprosthetic fractures (requires further imaging).
• Grossly malpositioned or loose components that necessitate revision surgery.
• Chronic dislocation with soft tissue contractures that prevent closed reduction.
• Infection at the surgical site (potential periprosthetic joint infection).
• Neuromuscular disorders with persistent instability that might require constraint implants.

3. Preparation

• Obtain proper imaging:
  • X-ray (AP pelvis, lateral views) to confirm dislocation and component positioning.
  • CT scan if component malalignment is suspected.
• Assess neurovascular status of the affected limb.
• Rule out fractures with additional imaging if needed.
• Ensure proper sedation or anesthesia is available for reduction.
• Have surgical backup ready in case closed reduction fails.

4. Special Instruments, Position, and Anesthesia

• Special Instruments:
  • Fluoroscopy (for confirmation of reduction).
  • Traction table (if closed reduction fails and open reduction is needed).
  • Periprosthetic fracture set (in case of intraoperative fracture).
  • Soft tissue retractors (for open reduction if necessary).
  • Specialized revision THA implants if revision is considered.
• Positioning:
  • Closed Reduction: Supine position for posterior dislocations; lateral decubitus position may be used in some cases.
  • Open Reduction: Supine or lateral depending on surgical approach.
• Anesthesia:
  • Closed Reduction: Deep sedation or general anesthesia with muscle relaxation.
  • Open Reduction: General anesthesia with full muscle relaxation.

5.  Technique & Approach

Closed Reduction Technique (Posterior Dislocation – Most Common)

1. Ensure adequate muscle relaxation.
2. Stimson Maneuver (Preferred):
   • Patient is placed prone with legs hanging over the edge of the bed.
   • Downward traction is applied on the femur while a second assistant applies pressure on the greater trochanter.
3. Allis Maneuver (Alternative):
   • Patient is in supine position.
   • Hip is flexed to 90°, an assistant stabilizes the pelvis, and longitudinal traction is applied.
   • The hip is then gently rotated and abducted to relocate.
4. Confirm reduction using fluoroscopy or post-reduction X-ray.

Open Reduction (For Irreducible Dislocation or Component Malpositioning)

• Posterior Approach (Most Common):
  • Incision over the posterolateral hip.
  • Dissection through the gluteus maximus.
  • External rotators are released (if not already detached).
  • Reduction performed manually with soft tissue clearing.
  • Assess component stability and repair capsule.
• Anterior Approach (For Anterior Dislocations):
  • Incision along the anterior hip.
  • Interval between tensor fascia lata and sartorius.
  • Direct access to the femoral head for manipulation and reduction.

6. Tips and Pearls

• Always confirm the absence of a fracture before attempting closed reduction.
• Use fluoroscopy to check implant positioning post-reduction.
• If reduction is difficult, increasing sedation and muscle relaxation may help.
• After reduction, test stability by taking the hip through a full range of motion.
• Consider abduction bracing in cases of recurrent instability.

7. What to Avoid

• Excessive force: May lead to acetabular or femoral fractures.
• Repeated unsuccessful attempts: Increases risk of soft tissue damage and fracture.
• Forcing reduction without imaging: Can worsen component malpositioning or dislodge implants.
• Over-reliance on bracing: It does not fix underlying instability issues.

8. Post Care Issues

• Post-reduction Imaging: Ensure proper reduction and component alignment.
• Restricted Movements: Avoid positions that caused the dislocation (posterior dislocation: avoid hip flexion >90°, internal rotation, and adduction).
• Rehabilitation: Gradual mobilization with physical therapy.
• Bracing: Consider in high-risk patients (e.g., neuromuscular conditions).
• Address Underlying Causes: Evaluate component positioning, soft tissue integrity, and patient compliance.
• Follow-up: Serial imaging to assess implant stability and rule out complications.