Possible Mechanism and Treatment Results of Combined Pediatric Fractures of the Humeral Lateral Condyle and Ipsilateral Ulnar Olecranon

Abstract

Objective

Combined fractures of the lateral condyle of the humerus and the ipsilateral ulnar olecranon are rarely seen in children. Therefore, the mechanism and suitable treatments remain debatable. This study describes the possible mechanism of combined humeral lateral condyle and ipsilateral ulnar olecranon fractures and presents the treatment results.

Methods

Children diagnosed with combined fractures of the humeral lateral condyle and ipsilateralulnar olecranon from July 2010 to July 2020 were retrospectively analyzed. Humeral lateral condyle fractures were treated with open reduction and internal fixation with bioabsorbable pins. Ulnar olecranon fractures were treated with closed reduction and percutaneous pinning with K‐wires for Mayo type IA fractures and with tension‐band wiring or a locking plate for Mayo type IIA fractures. The postoperative function and appearance of the elbow were evaluated using the Flynn criteria and Mayo Elbow Performance Score (MEPS) at follow‐up.

Results

The cohort comprised 19 patients aged from 4 to 11 years. Bony compression and avulsion by attached muscles and ligaments may be the leading factors causing the combined injuries, as the children fell with an outstretched and supinated elbow. The average follow‐up time was 33 months. High MEPS of >90 indicated that good to excellent results were obtained without complications.

Conclusions

This study proposed a reasonable hypothesis for the mechanism of combined humeral lateral condyle and ipsilateral ulnar olecranon fractures in children. Satisfactory outcomes were achieved with bioabsorbable pins for lateral condyle fractures and closed reduction and percutaneous pinning with K‐wires, tension‐band wiring, or locking plate for olecranon fractures.

Abstract

Hypothetical diagram of the mechanism of combined fractures of lateral condyle of the humerus and ipsilateral olecranon. This fracture occurs as the children fall on an outstretched and supinated elbow. An upward cubits varus stress is transmitted axially through the elbow joint to the lateral condyle. The olecranon is compressed and levered by the distal humerus during the process, resulting in fractures. Alternatively, the olecranon may be fractured as the forearm externally rotates against the distal humerus and pulls off the lateral condyle through tensed lateral collateral ligament complex. Contracted triceps muscle and arm extensors may also be important contributors.