In vivo biomechanical evaluation of a novel angle-stable interlocking nail design in a canine tibial fracture model.
OBJECTIVE
To compare clinical outcome and callus biomechanical properties of a novel angle stable interlocking nail (AS-ILN) and a 6 mm bolted standard ILN (ILN6b) in a canine tibial fracture model.


METHODS
Experimental in vivo study.


METHODS
Purpose-bred hounds (n = 11).


METHODS
A 5 mm mid-diaphyseal tibial ostectomy was stabilized with an AS-ILN (n = 6) or an ILN6b (n = 5). Orthopedic examinations and radiographs were performed every other week until clinical union (18 weeks). Paired tibiae were tested in torsion until failure. Callus torsional strength and toughness were statistically compared and failure mode described. Total and cortical callus volumes were computed and statistically compared from CT slices of the original ostectomy gap. Statistical significance was set at P < .05 RESULTS: From 4 to 8 weeks, lameness was less pronounced in AS-ILN than ILN6b dogs (P < .05). Clinical union was reached in all AS-ILN dogs by 10 weeks and in 3/5 ILN6b dogs at 18 weeks. Callus mechanical properties were significantly greater in AS-ILN than ILN6b specimens by 77% (failure torque) and 166% (toughness). Failure occurred by acute spiral (control and AS-ILN) or progressive transverse fractures (ILN6b). Cortical callus volume was 111% greater in AS-ILN than ILN6b specimens (P < .05).


CONCLUSIONS
Earlier functional recovery, callus strength and remodeling suggest that the AS-ILN provides a postoperative biomechanical environment more conducive to bone healing than a comparable standard ILN.
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, East Lansing, Michigan.
Loïc M
LM
Déjardin
Julien B
JB
Cabassu
Reunan P
RP
Guillou
Mark
M
Villwock
Laurent P
LP
Guiot
Roger C
RC
Haut
D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000662:veterinary*; D016723:Bone Remodeling; D002146:Bony Callus / Q000502:physiology; D004285:Dogs / Q000293:injuries* / Q000601:surgery; D004867:Equipment Design / Q000662:veterinary; D017102:Fracture Healing; D007794:Lameness, Animal / Q000503:physiopathology; D013977:Tibia / Q000473:pathology* / Q000601:surgery; D013978:Tibial Fractures / Q000601:surgery / Q000662:veterinary*