What is the step-by-step procedure for a fracture supracondylar humerus treated with a posterior approach by plating?

Posterior Approach for Supracondylar Humerus Fracture Plating: Step-by-Step Procedure

The posterior approach with plating is the recommended surgical technique for adult supracondylar humerus fractures as it provides optimal exposure for anatomical reduction and rigid fixation, allowing immediate postoperative movement for the best functional outcomes. 1

Patient Positioning and Preparation

• Position patient in lateral decubitus or prone position with the affected arm supported on an arm board
• Prep and drape the entire upper extremity from shoulder to hand
• Apply tourniquet to upper arm (if not contraindicated)
• Mark surgical landmarks including olecranon process and course of ulnar nerve

Surgical Approach

1. Incision:

   • Make a straight posterior midline incision centered over the olecranon process
   • Extend proximally 8-10 cm above the olecranon and distally 4-5 cm below it

2. Deep Dissection:

   • Identify and protect the ulnar nerve by palpating it in the cubital tunnel
   • Consider formal identification and mobilization of the ulnar nerve to prevent iatrogenic injury

3. Exposure Options:

   • Triceps-splitting approach:

     • Split the triceps muscle and tendon in the midline down to bone
     • Elevate the muscle off the posterior humerus subperiosteally
     • This approach shows better functional outcomes compared to olecranon osteotomy 2

   • Triceps-reflecting approach:

     • Reflect the triceps laterally or medially to expose the fracture site
     • Preserve the triceps insertion on the olecranon

Fracture Reduction and Fixation

1. Fracture Identification:

   • Identify the fracture lines and clean the fracture site of hematoma and debris
   • Assess the fracture pattern and comminution

2. Reduction:

   • Achieve anatomical reduction of the fracture fragments
   • Use bone clamps or K-wires for temporary stabilization
   • Confirm reduction with direct visualization and fluoroscopy

3. Plate Application:

   • Select appropriate anatomical plate (posterior or dual plating)
   • Contour the plate to match the posterior surface of the distal humerus
   • Position the plate to avoid impingement on the olecranon fossa
   • Apply the plate with screws proximally in the humeral shaft and distally in the distal fragment
   • Ensure adequate screw purchase in both fragments

4. Fixation Verification:

   • Check stability of fixation by gently moving the elbow through range of motion
   • Confirm plate and screw position with fluoroscopy
   • Ensure no hardware impingement during elbow flexion and extension

Wound Closure

1. Triceps Repair:

   • Repair the triceps mechanism with strong non-absorbable sutures if split approach was used
   • Ensure secure reattachment to restore extensor mechanism function

2. Layered Closure:

   • Close deep fascia with absorbable sutures
   • Close subcutaneous tissue and skin in standard fashion
   • Consider drain placement if significant bleeding is present

Post-operative Management

1. Immobilization:

   • Apply posterior splint with elbow at 90° flexion for initial comfort
   • Maintain for 1-2 weeks until wound healing is adequate

2. Early Mobilization:

   • Begin gentle active range of motion exercises as soon as pain allows
   • Early mobilization is crucial for preventing stiffness and achieving good functional outcomes 1

3. Follow-up:

   • Regular radiographic assessment to monitor fracture healing
   • Progressive rehabilitation protocol to restore strength and function

Potential Complications and Pitfalls

• Ulnar nerve injury: Careful identification and protection during surgery is essential
• Triceps weakness: Can occur with inadequate repair of the triceps mechanism
• Elbow stiffness: Early mobilization is critical to prevent this complication
• Hardware prominence: Proper plate contouring and positioning is necessary
• Infection: Meticulous surgical technique and appropriate antibiotic prophylaxis

Special Considerations

• In pediatric patients, closed reduction with percutaneous pinning is generally preferred over open reduction and plating 3, 4
• The posterior approach provides excellent exposure but requires careful handling of soft tissues to minimize complications
• Anatomical reduction with rigid fixation is crucial for allowing immediate postoperative movement and achieving optimal functional outcomes 1