What is the step-by-step procedure for treating a posterior malleolar fracture using plating through a posterior approach?

Step-by-Step Procedure for Posterior Malleolar Fracture Fixation via Posterior Approach

The posterior approach with direct plate fixation is the most effective technique for treating posterior malleolar fractures, providing superior visualization, anatomic reduction, and stable fixation that leads to better functional outcomes and lower complication rates compared to indirect reduction techniques.

Patient Positioning and Preparation

1. Position the patient prone on a radiolucent operating table
2. Place a bolster under the ankle to allow for foot mobility during the procedure
3. Administer prophylactic antibiotics (cefazolin 1-2g IV or clindamycin 600-900mg IV if allergic)
4. Prepare the surgical site with alcohol-based antiseptic solution
5. Apply a tourniquet to the thigh and elevate the limb for 2 minutes before inflation

Surgical Approach

1. Make a 10-12cm longitudinal or slightly curved incision centered between the lateral border of the Achilles tendon and the posterolateral edge of the fibula
2. Identify and protect the sural nerve, which typically runs along the lateral border of the Achilles tendon
3. Develop the interval between the peroneal tendons laterally and the flexor hallucis longus medially
4. Retract the peroneal tendons laterally and the flexor hallucis longus medially
5. Identify and protect the posterior tibial neurovascular bundle, which lies medial to the flexor hallucis longus

Fracture Exposure and Reduction

1. Incise the posterior capsule of the ankle joint to expose the posterior malleolar fragment
2. Remove any hematoma and debris from the fracture site
3. Elevate the posterior malleolar fragment if impacted
4. Anatomically reduce the fragment under direct visualization, ensuring restoration of the articular surface
5. Hold the reduction temporarily with K-wires placed outside the planned plate position
6. Confirm reduction with fluoroscopy in multiple planes

Fracture Fixation

1. Apply an appropriately sized posterior buttress plate (one-third tubular or anatomic posterior distal tibia plate)
2. Position the plate to buttress the posterior malleolar fragment
3. Secure the plate with at least 2-3 screws in the distal fragment and 2-3 screws in the proximal fragment
4. Ensure screws in the distal fragment do not penetrate the articular surface
5. Remove temporary K-wires
6. Perform final fluoroscopic assessment to confirm anatomic reduction and proper implant position

Wound Closure and Post-operative Care

1. Irrigate the wound thoroughly
2. Close the posterior capsule with absorbable sutures
3. Perform layered closure of the deep fascia, subcutaneous tissue, and skin
4. Apply a well-padded posterior splint with the ankle in neutral position
5. Convert to a removable boot at 2 weeks for early range of motion exercises
6. Maintain non-weight bearing for 6 weeks, then progress to partial weight bearing
7. Begin full weight bearing at 8-12 weeks based on radiographic healing

Clinical Pearls and Pitfalls

• Direct visualization advantage: The posterolateral approach allows direct visualization of the fracture, resulting in more accurate reduction compared to indirect anterior approaches 1, 2
• Plate vs. screw fixation: Recent evidence shows that plate fixation provides better stability, shorter healing time, and improved functional outcomes compared to screw fixation alone 3
• Fragment size consideration: While traditionally only fragments >25% of the articular surface were fixed, current evidence supports fixing even smaller fragments when displaced, as they contribute to ankle stability 4
• Neurovascular protection: Careful identification and protection of the sural nerve and posterior tibial neurovascular bundle is essential to prevent iatrogenic injury
• Syndesmotic assessment: After posterior malleolar fixation, assess the syndesmosis for stability as posterior malleolar fractures are often associated with syndesmotic injury
• Early mobilization: Begin early ankle range of motion exercises at 2 weeks to prevent stiffness while protecting the fixation

This approach has demonstrated excellent outcomes with a median American Orthopaedic Foot and Ankle Society (AOFAS) score of 93 (range 58-100) and good functional recovery in long-term follow-up studies 4. The posterolateral approach allows for anatomic reduction and stable fixation with few local complications, leading to better functional outcomes compared to traditional indirect reduction techniques 2, 5.