Pediatric Salter-Harris Type IV Distal Femoral Physeal Fracture: A Case Study
Key Takeaway
A Salter-Harris type IV distal femoral physeal fracture involves both the epiphysis and metaphysis, extending through the growth plate. Diagnosis typically begins with clinical presentation and plain radiographs, followed by CT imaging for precise evaluation of articular displacement and surgical planning. Neurovascular assessment is critical due to the high-energy mechanism often associated with these pediatric injuries.
A 12-year-old male presents following a high-energy T-bone motor vehicle collision. He is hemodynamically stable, but examination of the right knee reveals significant valgus deformity, tense hemarthrosis, and an inability to bear weight. This is your initial radiograph. Describe your findings and classify the injury.
Candidate: The radiograph shows a distal femoral fracture. It appears to be a Salter-Harris IV fracture as it involves the epiphysis, physis, and metaphysis. There is a displaced articular fragment and valgus angulation. I would also worry about neurovascular injury given the high-energy mechanism.
Failure to comment on the "Thurstan Holland" fragment or the specific articular step-off. Candidates often overlook the displacement of the posterior metaphysis, which puts the popliteal artery at risk. Simply saying "it’s a fracture" without discussing the implications for the physis and growth potential is a major point-loss.
“This is a Salter-Harris Type IV physeal fracture of the distal femur. Radiographically, we see a vertical fracture line traversing the epiphysis, physis, and metaphysis with a characteristic Thurstan Holland fragment. There is significant valgus angulation and articular incongruity. Given the patient’s skeletal age (Tanner II), this carries a high risk of growth arrest and angular deformity due to potential physeal bar formation. I would immediately perform a detailed neurovascular assessment, specifically checking distal pulses and ABI, due to the proximity of the popliteal artery to the displaced metaphyseal fragment.”
You decide this patient requires open reduction and internal fixation. During your pre-operative planning, you discuss the risks of soft tissue interposition. Why is this a specific concern in this injury, and how does it influence your surgical approach?
Candidate: In these injuries, the periosteum often gets trapped in the fracture line. This makes closed reduction very difficult. I would plan for an open reduction to clear the soft tissue and ensure anatomical reduction of the articular surface.
Assuming the periosteum is the only structure at risk or failing to emphasize the necessity of direct visualization to prevent physeal bar formation. A failing candidate might suggest closed manipulation under fluoroscopy, which is high-risk for physeal damage.
“In Salter-Harris IV injuries, the tear in the periosteum often becomes incarcerated within the fracture gap. This is the primary obstacle to closed reduction. Attempting closed reduction can further damage the germinal layer of the physis. Therefore, I would proceed with a formal arthrotomy—likely medial parapatellar—to allow for direct visualization. This ensures anatomical articular reduction, removal of the entrapped periosteum, and the ability to confirm that no hardware crosses the physis, which is essential to minimize the risk of premature epiphysiodesis.”
The surgery is successful and hardware is placed. What is your long-term follow-up strategy for this patient, and what specific complications are you screening for?
Candidate: I would see them back in the clinic to check the X-rays. I need to make sure the fracture heals and check for any leg length discrepancy. I would remove the metalwork later on.
Vague follow-up plan. Failing to mention "full-length standing radiographs" (scanograms) or not understanding the timeline of growth arrest (which may not manifest for 6-12 months post-injury).
“Long-term follow-up is mandatory until skeletal maturity. I would schedule clinical and radiographic assessments at 6 months, 12 months, and annually thereafter. I am screening for three major complications: 1) Physeal bar formation (premature epiphysiodesis), 2) Progressive angular deformity (valgus/varus), and 3) Limb length discrepancy. I would utilize standing full-length limb radiographs (scanograms) to quantify these. Additionally, I would plan elective hardware removal at approximately 5-6 months post-injury to prevent localized tethering, provided the fracture is consolidated.”
