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SummaryAcetabular cup displacement (ACD) was identified as a complication of cemented modular total hip replacement in seven dogs. ACD is characterized by mechanical failure of the polyethylene-cement interface and subsequent cup migration, and is a clinical entity distinct from classical aseptic loosening. ACD is a sequela of extrusion of the cup and lateralization of the prosthetic load-bearing axis. The acetabular cup displacement ratio (ACDR) has a statistically significant effect on whether ACD develops (P

SummaryTo measure the change of length patterns of nine different simulated anterior cruciate ligament (ACL) reconstructions in the canine and human knee.Six fresh-frozen canine cadaver knees and six fresh-frozen human cadaver knees were used in this study. All of the soft tissues were removed from each cadaver knee, leaving the menisci, collateral ligaments and cruciate ligaments intact. After fixation of the femur to a custom-made frame, the ACL was excised. Three tunnels were made each at the ACL origin and insertion, making possible nine reconstruction combinations. A modified intra-articular technique was used to measure change of length, in mm, of each ACL reconstruction through a range of motion of 0 degrees (full extension) to 135 degrees of flexion. A rankorder list of reconstruction combinations was determined. The most isometric combination was determined for the canine and human knees, and trends in length patterns were also evaluated in both species relative to femoral and tibial position. Statistical significance was determined by ANOVA.A combination joining a point caudal to the ACL origin (over-the-top) and anterior on the tibial insertion was found to be the most isometric combination in both the canine and human. The trends in change of length patterns across all reconstruction combinations were similar in the dog and man. Isometry was improved as the reconstruction was placed further posterior on the femur and anterior on the tibia. Conclusions: The canine knee is an appropriate animal model for the study of isometry of the human ACL and its reconstructions.The length patterns of nine simulated Anterior Cruciate Ligament (ACL) reconstructions were determined in the dog and man. In both species, the most isometric reconstruction was one joining points corresponding to a position at the posterior edge of the intercondylar roof of the femur (over-thetop) with a position anterior on the ACL insertion. For the sake of clarity the term anterior cruciate ligament has been used, throughout, for both species, instead of the cranial cruciate ligament (CCL) in the dog. Also knee has been used in place of stifle for the dog.

SummaryFifty healthy adult Suffolk cross sheep were evaluated as a research animal for cemented total hip replacement. The surgical technique, peri-operative care, and long-term evaluation of the animals is reported. A modular cemented canine hip replacement system was used in this project. Postoperative fractures of the operated femur were observed in five animals. Two sheep developed septic loosening of the acetabular components. Two sheep experienced immediate postoperative luxations. One animal developed an acetabular fracture and infection. Five sheep exhibited mild lameness of the operated limb one year postoperatively, while all others had a normal gait. Postoperative activity level played a significant role in the development of femur fractures.Fifty adult Suffolk cross sheep were evaluated as a research animal for cemented total hip replacement. The surgical technique, peri-operative care and long-term evaluation of the animals are reported.

Total hip replacements in the dog have become well established over the past 20 years as an effective method for treating disabling hip conditions. A fixed head prosthesis has been the mainstay during most of this period. Return to normal function with this prosthesis has been reported at 95 per cent. Although patient selection, pre- and post surgical care, the surgical technique and the treatment or prevention of complications has been continually improved, it was not until recently that the prosthesis and its instrumentation were improved. Now a modular prosthesis with improved instrumentation gives the veterinary surgeon ‘state of the art’ implants and instruments. The prosthesis is easier to implant, the surgeon has greater flexibility in surgery and improved results are expected. Total hip replacement continues to be an effective way to give dogs a pain-free, mechanically sound hip joint.

A fracture is a complete or incomplete break in the continuity of bone or cartilage or both. It is accompanied by soft tissue injury and impairment of blood supply and function. Fracture disease may be defined as any pathological change in the soft tissues, joint, or bones associated with treatment of a fracture and resulting in impaired limb function. The term clinical union indicates a state in which healing bone is sufficiently strong for all fixation devices to be removed. The term osteosynthesis is used for internal fixation of a fracture by means of a mechanical device, e.g., pin, screw, plate.

Fractures of the scapula can be classified into four groups on the basis of the anatomic structures involved: 1. Fractures of the glenoid (articular surface) 2. Fractures of the neck 3. Fractures of the acromion 4. Fractures of the body and spine

No surgical procedure is free of complications. Determining the reason that a complication of a fracture repair occurred and developing a treatment plan are important if the objectives of fracture treatment are to be met. It is also necessary to deal with owners, and, sometimes, other veterinarians in meeting these objectives.

Describes the use of selective oxidation and ion implantation to fabricate integrated circuits. The technique of selective oxidation is used to fabricate a `walled emitter' structure as proposed by Panousis. This allows a substantial reduction in transistor size, for a given active area, over standard fabrication techniques. At the same time, parasitic device capacitances are reduced and a considerable improvement in circuit performance is realized. The impurity distribution in the various components is established by the extensive use of ion implantation. It has been demonstrated, experimentally, a 30-pJ resistor transistor-transistor logic gate fabricated using the collector diffusion isolation technology, can be fabricated in oxide isolated monolithic technology with a power-delay product of 6 pJ. Current-mode logic gates have been fabricated with a power-delay product of 1 pJ.

Brucella canis was isolated from the cement or bone surrounding a hip prosthesis after total hip replacement was performed for treatment of hip dysplasia in 2 dogs. Lameness or signs of infection were not evident for 9 and 16 months after surgery. Osteomyelitis surrounding the prostheses was detected radiographically only after the lameness developed. The origin of the B canis infection in the 2 dogs was believed to be hematogenous because of the biologic behavior of this organism and because of the duration of excellent limb function after hip replacement. A slide agglutination test for B canis should be performed as a screening test on any canine total hip candidate when the anamnesis and physical examination indicate that the dog may have been exposed to or infected with B canis.

Hundreds of total hip replacements in dogs have been performed at the Ohio State University of Veterinary Medicine since August 1976. Dogs with disabling diseases or conditions of the hip are candidates for the THR. The technique provides the dog with a pain free, mechanically sound ball and socket joint. The most commonly encountered complication is dislocation, while the most disastrous complication is infection. Complications can be minimized through adherence to detail during the procedure. By following strict aseptic principles, surgical technique and postoperative care, successful hip function has been achieved in 94.7% of the cases.

SummaryThe aim of this pilot study was to define the mechanism and mode of polyethylene wear in acetabular components retrieved from seven dogs following therapeutic total hip replacement. The articular surface of each acetabular component was examined using contact profilometry and scanning electron microscopy (SEM). Peak-tovalley distance (P-V) and arithmetic average surface roughness (Ra) were calculated for each quadrant of the surface. Deformation of the regular profile of the machining lines was the least severe form of surface alteration. Randomly orientated scratches, fine tapered filaments, ripples, and coarse surface shredding were common SEM observations. Gouging of the convex surface of the cup was seen in two cases following failure of the polyethylenecement interface. Wear of the nonarticular acetabular rim suggested neck impingement in one case. P-V and Ra were significantly lower in the craniodorsal zone, compared to the average roughness of the other three quadrants (p < 0.05). Abrasion, adhesion and fatigue were the principal mechanisms of polyethylene wear, and were implicated in the production of polyethylene particulate debris. Meticulous removal of abrasive third bodies at the time of surgery, and correct orientation of the acetabular component, should reduce early and severe wear.Polyethylene wear is inevitable following metal-on-polyethylene total hip replacement. In this study, the nature of polyethylene wear in retrieved canine acetabular components was defined, using contact profilometry and scanning electron microscopy. Abrasion, adhesion and fatigue were the principal mechanisms of wear, and were implicated in the production of polyethylene particulate debris.