The purpose of this study was to test the biomechanical properties of locking and nonlocking plates using one-third tubular and periarticular plate designs in an osteoporotic distal fibula fracture model.
Twenty-four cadaveric specimens, whose bone mineral densities were obtained using dual x-ray absorptiometry scans, were tested. The fracture model simulated an OTA 44-B2.1 fracture. The constructs included (1) nonlocking one-third tubular plate, (2) locking one-third tubular plate, (3) nonlocking periarticular plate, and (4) locking periarticular plate. The specimens underwent axial loading followed by torsional loading to failure. Statistical analysis was performed using Kruskal–Wallis testing and further analysis with Mann–Whitney testing.
The periarticular plates had greater rotational stiffness compared with the one-third tubular plates (P = 0.04). The nonlocking plates had greater torque to failure than the locking plates (P = 0.01). The nonlocking one-third tubular plate had greater torque to failure than the locking one-third tubular plate (P = 0.03). No significant differences were found in any of the comparisons regarding axial stiffness.
In biomechanical testing using an osteoporotic model of OTA 44-B2.1 fractures, periarticular plates were superior to one-third tubular plates in rotational stiffness only. Locking plates did not outperform their nonlocking counterparts. Periarticular plates should be considered when treating osteoporotic distal fibula fractures, but one-third tubular plates and nonlocking plates provide adequate fixation for these injuries.
Department of Orthopaedic Surgery, Saint Louis University, St Louis, MO.
Reprints: Lisa K. Cannada, MD, Department of Orthopaedic Surgery, St Louis University, 3635 Vista Avenue, 7th floor, St Louis, MO 63110, USA (e-mail: email@example.com).
Presented at the Mid-America Orthopaedic Association Annual Meeting, 2011, Tuscon, AZ, and at the American Academy of Orthopaedic Surgeons Annual Meeting, 2012, San Francisco, CA.
The authors report no conflict of interest.
Supported by grants in the form of plates and screws from Synthes, Paoli, PA, and Zimmer, Warsaw, IN.
Accepted December 05, 2012