Antebrachiometacarpal arthrodesis in five dogs.

CASE REPORTS: Five dogs (4 with severe carpal contracture, 1 with a chronically infected carpal joint) underwent antebrachiometacarpal arthrodesis. Excision of all carpal bones, except the accessory carpal bone, was done, either because of persistent infection or to allow the manus to be arthrodesed in a functional position. All five dogs developed varying degrees of soft tissue swelling of the surgical site following surgery. All five arthrodeses achieved complete osseous union within 4-67 weeks. The immediate postoperative distal radiometacarpal frontal plane angulation ranged from 1° to 19° (mean ± SD: 7 ± 8°). The immediate postoperative distal radiometacarpal sagittal plane angulation ranged from 6° to 26° (mean ± SD: 17 ± 9°). Plate coverage of the secured metacarpal bone(s) ranged from 75% to 87% (mean ± SD: 80 ± 4%). Infection necessitated plate removal in four dogs, 3-17 (mean ± SD: 8 ± 6) months following surgery and 0-15 (mean ± SD: 5 ± 7) weeks following radiographic documentation of complete osseous union. CONCLUSION: Despite one dog having marked elbow incongruency and degenerative joint disease and one dog having an ipsilateral radial nerve deficit, all five dogs improved and had acceptable limb function at the time of the final evaluation, which ranged from 25 to 296 (mean ± SD: 99 ± 111) weeks following surgery.

Biomechanics of bone and fractures.

A basic understanding of biomechanics, the material and structural properties of bone, and the effects that forces have on long bones enables the veterinary orthopedic surgeon to make rational decisions in selecting the most appropriate method of fracture fixation. This knowledge should enhance a surgeon's clinical ability to create a biomechanically stable environment at the fracture site that is conducive to rapid bone healing and early return to function of the patient. Furthermore, the ability to comprehend biomechanics as it pertains to fracture management enables the surgeon to scientifically critique new implant systems as they are developed with regard to their inherent ability to effectively neutralize the potential disruptive forces acting on a fracture after stabilization.

Potential central nervous system complications of von Willebrand's disease.

Three Doberman pinschers were presented on emergency referral for progressive neurological deficits. All three dogs had a similar onset of clinical signs associated with an apparently minor traumatic event. Each dog progressed to significant neurological dysfunction including paraplegia, tetraplegia, and/or loss of deep pain sensation. None of the animals was apparently affected by cervical vertebral instability ("Wobbler's Syndrome"). All were confirmed to have von Willebrand's disease. In all cases, significant epidural hemorrhage was identified. The etiology of each hemorrhage, however, was different for each animal. The cases presented here demonstrate a potential relationship between neurological deficits and the patient's ability to effectively coagulate blood. Hemostatic abnormalities, such as von Willebrand's disease, should be included as possible differential diagnoses or contributing factors in animals demonstrating neurological deficits. These abnormalities should especially be considered following trauma, intervertebral disk extrusion, or spinal surgery.

Cystotomy closure. A comparison of the strength of appositional and inverting suture patterns.

Dorsal cystotomies were performed in 60 healthy dogs. Twenty bladders were closed with a single-layer interrupted appositional suture pattern, 20 with a two-layer interrupted appositional suture pattern, and 20 with a two-layer continuous inverting suture pattern. Four dogs from each group were euthanatized at hours 0, 3, 12, 18, and 24. Mechanical strength of the cystotomy closures was evaluated by calculating the circular bursting wall tension. The single-layer interrupted appositional suture pattern was as strong as both two-layer suture patterns at hours 3, 12, 18, and 24. The two-layer interrupted appositional suture pattern was as strong as the two-layer continuous inverting suture pattern during the first 24 hours.

Static strength evaluation of sacroiliac fracture-separation repairs.

The relative static strengths of seven fixation configurations for the repair of sacroiliac fracture-separations were determined. The fixation techniques were two 3.5 mm screws, one 4.5 mm screw, one 4.5 mm screw and a pin, two 4.5 mm screws, one 6.5 mm screw, one 6.5 mm screw and a pin, and two 6.5 mm screws. Each configuration was subjected to a torsional, a bending, and a shear disruptive force while the maximum load tolerated before failure was measured. Two screws were stronger than a single screw of similar size, two small screws were stronger than a single larger screw, and a reduction pin added no significant strength to a single screw repair. It was concluded that use of the largest screws possible will maximize the strength of a sacroiliac fracture-separation repair.