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.
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.
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.
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.
aMacDill Air Force Base, Tampa, FL
bFischell Department of Bioengineering, Orthopaedic Mechanobiology Laboratory, University of Maryland, College Park, MD
cUniversity of Maryland School of Medicine, Department of Orthopaedics, Baltimore, MD
dR Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD
eUnion Memorial Orthopaedics and Sports Medicine, Baltimore, MD
Sources of Funding: In support of their research for this work, one or more of the authors received an AO North America grant for $5000. All devices for this work were provided by Synthes, Inc. (Paoli, PA).
Financial Disclosure: Dr O’Toole is a paid consultant for Synthes and has received grants from Synthes and Stryker. Dr. Murthi serves as an associate editor for Current Orthopaedic Practice and is on the Board of J Bone Joint Surg. He is a paid consultant for Zimmer, Integra, and Arthrex. He has received royalties from Integra. The other authors have no financial disclosures.
Correspondence to Robert V. O’Toole, MD, R Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, 22 South Greene Street, T3R62, Baltimore MD 21201 Tel: 410-328-6292; fax: 410-328-2893; e-mail: email@example.com