Evaluation using hoof wall strain gauges of a therapeutic shoe and a hoof cast with a heel wedge as potential supportive therapy for horses with laminitis.
OBJECTIVE
To evaluate using strain gauges, a hoof cast with heel wedge, and a therapeutic shoe with unsupported toe for their effectiveness in redistribution of load from the dorsal hoof wall.


METHODS
In vitro biomechanical study.


METHODS
Twenty forelimb specimens.


METHODS
Rosette strain gauges were placed on the dorsal and lateral hoof wall of 20 normal shaped hooves. Limbs were loaded vertically using a tensile testing machine with a 1 Hz sinusoidally cycling load up to 3000 N during 15 seconds. Mean values of principal strain and direction at 2500 N load were calculated for 3 experimental conditions (unshod, therapeutic shoe with unsupported toe, and hoof cast with heel elevation) and tested by ANOVA (P<.05).


RESULTS
Vertical limb loading in an unshod hoof leads to a biaxial compression of the dorsal wall with high longitudinal compression (epsilon2 = -1515 microm/m). Principal strain at the dorsal wall (epsilon2) was decreased by 23% with the therapeutic shoe and by 59% with the hoof cast. On the lateral hoof wall principal strain was unchanged with the shoe, but increased by 34% with the cast.


CONCLUSIONS
Strain measurements indicate unloading of the dorsal hoof wall by both methods with the cast being more effective than the shoe.


CONCLUSIONS
The hoof cast with wedge offers substantial unloading of the dorsal wall, but increases load on the quarter. Therefore a hoof cast would likely be most helpful in acute laminitis when palmar structures can still bear load. The therapeutic shoe offers rehabilitation and regrowth of the dorsal wall without increased load on the quarter wall.
Hansen
Nicolas
N
Department for Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria.
Buchner
H H Florian
HH
Haller
Jürgen
J
Windischbauer
Gerhard
G
D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D002102:Cadaver; D002370:Casts, Surgical / Q000662:veterinary*; D005534:Foot Diseases / Q000601:surgery / Q000628:therapy / Q000662:veterinary*; D005552:Forelimb; D006724:Hoof and Claw / Q000502:physiology*; D006734:Horse Diseases / Q000601:surgery / Q000628:therapy*; D006736:Horses / Q000502:physiology; D066298:In Vitro Techniques; D007794:Lameness, Animal / Q000628:therapy; D011312:Pressure; D012775:Shoes; D013314:Stress, Mechanical; D013718:Tensile Strength; D016474:Weight-Bearing / Q000502:physiology