Dual bone fixation: a biomechanical comparison of 3 implant constructs in a mid-diaphyseal fracture model of the feline radius and ulna

OBJECTIVE: To compare the biomechanical properties of dual bone fixation (DBF) constructs to radial locking compression plating (LCP) in an ex vivo feline antebrachial fracture gap model.

STUDY DESIGN: Ex vivo study.

SAMPLE POPULATION: Cadaveric feline antebrachii (n=12 pairs).

METHODS: Antebrachii were radiographed to confirm normal skeletal appearance and maturity. After creation of a 5 mm radial and ulnar ostectomy, each antebrachium received 1 of 3 constructs using an incomplete randomized block design (n=8 per group). All groups received a 10 hole 2.0 mm radial LCP. DBF groups received either a 1.2 mm ulnar intramedullary pin (LCP with pin) or an 8 hole 2.0 mm ulnar LCP in addition to the radial LCP. Biomechanical testing was performed in axial compression and caudocranial and mediolateral 4-point bending before destruction in axial compression.

RESULTS: DBF constructs (LCP with pin and dual LCP) were significantly stiffer than radial LCP alone in axial compression and caudocranial bending. There were no differences between LCP with pin and dual LCP constructs in axial compression and caudocranial bending or between any constructs in mediolateral bending. Failure load was significantly greater for dual LCP than LCP with pin or LCP alone constructs. Failure loads were not different between LCP with pin and LCP alone.

CONCLUSION: DBF significantly increased construct stiffness and strength. Given the high complication rate reported in cat antebrachial fractures when only the radius is stabilized, surgeons should consider DBF.