Mechanical performance of dual and single locking plate constructs for fixation of humeral mid- diaphyseal fractures: a finite element study with Retrospective Case Series




Luedke, Colten


Journal Title

Journal ISSN

Volume Title



Purpose: To compare the mechanical performance of four different locking plate constructs (three single and one dual plate) for mid-diaphyseal humeral fracture fixation and present our clinical case series Materials and Methods: Five humeral shaft finite element models (1 intact and 4 fixation) were loaded in torsion, compression, posterior-anterior (PA) bending, and lateral-medial (LM) bending. A comminuted fracture was simulated by a 1-cm fracture gap. Fracture fixation was consistsed of: (A) 4.5-mm 9-hole large fragment plate (wide), (B) 4.5-mm 9-hole large fragment plate (narrow), (C) 3.5- mm 9-hole small fragment plate, and (D) one 3.5-mm 9-hole small fragment plate and one 3.5-mm 7- hole small fragment plate. Outcome measures include construct stiffness, and hardware stresses. The clinical series of patients include 41 patients having undergone dual plating of humeral shaft fractures with primary outcomes of time to healing, nonunion and failures. Results: Model A showed the best outcomes in torsion and PA bending, whereas Model D outperformed the others in compression and LM bending. Stress concentrations were located near and around the unused screw holes for each of the single plate models and at the neck of the screws just below the plates for all the models studied. Of the 41 patients included in our clinical series, 26 were available at final follow up. All 26 patients showed clinical and radiographic healing. 2 complications were noted: 1 hardware failure due to infection, 1 infection at an olecranon plate. Conclusions: The results support using a dual small fragment locking plate construct as an alternative in cases where crutch weight-bearing (compression) tolerance may be important and where anatomy limits the size of the bone segment available for plate fixation. Our clinical series show the 26 patients available at final follow-up all demonstrate clinical and radiographic healing.