Anteroinferior 2.7-mm versus 3.5-mm plating of the clavicle: A biomechanical study.
BACKGROUND
Lower patient satisfaction and high rates of plate prominence has led to the use of lower profile, smaller plates in the treatment of midshaft clavicle fractures. Specifically regarding the use of 2.7mm reconstruction plates, there lacks biomechanical comparison to its more robust 3.5mm counterpart. This study was designed to compare the mechanical properties of anteroinferior plate fixation on a clavicle fracture model using either 2.7mm or 3.5mm reconstruction plates.


METHODS
Forty-eight synthetic left clavicles were divided into two groups based on the type of fixation: 3.5mm or 2.7mm pelvic reconstruction plate fixed in the anteroinferior position. Fixation was tested on AO/OTA 15B1.3 transverse midshaft fractures. Each specimen underwent the following three mechanical tests: axial compression, torsion, and four-point bending.


RESULTS
Significant differences were observed in axial (p=0.016) and torsional (p=0.00097) stiffness between the two groups. The average bending rigidity (EI) was found to be significantly lower for the 2.7-mm plates as compared to the 3.5-mm plates (p=0.03). The loading scenarios performed in the mechanical tests did not lead to failure of any implants.


CONCLUSIONS
While our results show clear mechanical superiority of 3.5-mm reconstruction plates over 2.7-mm plates, superior results in the clinical setting may not necessarily translate. With exceptional mechanical strength also noted for the 2.7mm plate, well above the biomechanical properties of an intact clavicle, these results may obviate the need for robust plates in general.
Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, United States.
Nicholas
N
Pulos
Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, NY, NY 10003, United States.
Richard S
RS
Yoon
McKay Orthopaedic Research Lab, University of Pennsylvania, Philadelphia, PA 19104, United States.
Snehal
S
Shetye
McKay Orthopaedic Research Lab, University of Pennsylvania, Philadelphia, PA 19104, United States.
Michael W
MW
Hast
Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, NY, NY 10003, United States.
Frank
F
Liporace
Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, University of Pennsylvania, 6th Floor, 3737 Market Street, Philadelphia, PA 19104, United States. Electronic address: derek.donegan@uphs.upenn.edu.
Derek J
DJ
Donegan
D001187:Artificial Organs; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D001842:Bone and Bones / Q000033:anatomy & histology / Q000601:surgery*; D002968:Clavicle / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008953:Models, Anatomic
Anteroinferior plating; Biomechanical study; Clavicle fracture; Midshaft fracture