Background: We compared the biomechanical stability of a standard precontoured two-plate locked construct with that of a single laterally placed locked plate for extraarticular supracondylar distal humeral fractures.
Methods: Extraarticular supracondylar humeral fractures were created in matched pairs of nonosteoporotic cadaver humeri. Specimens were plated with a single locked plate placed posterolaterally or two precontoured locked plates placed orthogonally. Both constructs were instrumented in a hybrid manner with locking and nonlocking screws. Each sample underwent cyclic loading in flexion and varus to failure. Average cycles to failure, force to failure, displacement, and mechanical stiffness were compared.
Results: Stiffness was 1072 N/mm for the single-plate construct and 722 N/mm for the two-plate construct (P=0.06). Average number of cycles to failure was 3586 for the single-plate and 2772 for the two-plate construct (P=0.42). Force to failure averaged 428 N for the single-plate and 380 N for the two-plate construct (P=0.56). All constructs failed through the plate-bone interface without failure of the devices.
Conclusions: A single plate designed specifically for fractures of the distal humerus is biomechanically equivalent to two precontoured plates also designed for the distal humerus. The finding might be clinically significant because the single-plate technique potentially reduces surgical time and exposure to the posterior and medial aspects of the elbow. Decreased exposure, especially to the medial elbow, might reduce iatrogenic injury.