Pediatric Supracondylar Fracture — ABOS Oral Boards Preparation
What examiners expect and how to prepare
Clinical Scenario
A 6-year-old right-hand-dominant girl is brought to the emergency department by her parents after falling from a playground slide, landing on her outstretched left arm. She is crying and holding her left elbow. She has no medical history and no prior fractures. Her parents report that she fell approximately 4 feet. On exam, the left elbow is swollen with a visible S-shaped deformity. There is ecchymosis in the antecubital fossa. She is neurovascularly intact — she can make an OK sign (AIN), extend her fingers and wrist (PIN), has intact sensation in the median, ulnar, and radial distributions, and has a palpable radial pulse with brisk capillary refill. She is reluctant to move the elbow. Compartments in the forearm are soft.
AP and lateral radiographs of the left elbow reveal a completely displaced extension-type supracondylar humerus fracture (Gartland III). The distal fragment is displaced posteriorly and medially. There is no associated condylar fracture. The anterior humeral line does not intersect the capitellum. The Baumann angle is altered, suggesting varus malalignment.
You performed closed reduction and percutaneous pinning in the operating room under general anesthesia within 4 hours of presentation. Reduction was achieved with traction, correction of medial displacement, and hyperflexion. Three laterally placed divergent 0.062-inch K-wires were used for fixation. Intraoperative fluoroscopy confirmed restoration of the anterior humeral line, Baumann angle, and medial-lateral alignment. Post-operatively, the arm was placed in a well-padded long arm posterior splint at 60 degrees of flexion. The family was counseled on pin site care and neurovascular monitoring. Pins were removed in clinic at 4 weeks with progressive range of motion.
What Examiners Look For
- Data gathering: Neurovascular exam in a 6-year-old — you must demonstrate competence in assessing AIN, PIN, and ulnar nerve function in a scared child. How do you test these?
- Diagnosis: Gartland classification and what drives treatment at each grade. What radiographic landmarks confirm adequate reduction (anterior humeral line, Baumann angle)?
- Treatment plan: Why closed reduction and pinning versus open reduction? What are your indications for converting to an open approach?
- Technical skill: Pin configuration — lateral-only versus crossed pins. Describe the evidence on ulnar nerve injury with medial pin placement.
- Complications: What if the child has a pulseless but pink hand? Describe your algorithm — what is the role of vascular exploration versus observation.
- Ethics: Communicating with parents — how do you explain the injury, the surgery, and the risks in a way they can understand and consent to?
Common Pitfalls
- Missing a vascular injury — a pulseless, well-perfused hand does not mean you can ignore the vascular status. Know your algorithm.
- Placing a medial pin without protecting the ulnar nerve — this is the most common iatrogenic complication and examiners will probe it.
- Not recognizing a flexion-type variant — these are less common but managed differently (anterior displacement, prone positioning).
- Splinting in excessive flexion — this can compromise vascular status in a swollen elbow. Check perfusion after splint application.
- Forgetting to discuss child abuse in the differential for any pediatric fracture — it is expected that you acknowledge this.
Key Classifications
Free — takes 3 minutes