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Author: Simon C. Roe

Abstract

Objective—To compare tension of 3 cerclage wire knots tied by surgeons of various abilities and experience.

Design—Cross-sectional study.

Sample Population—Participants and faculty at a postgraduate course in veterinary orthopedics.

Procedure—Subjects tied a cerclage of their choice on an instrumented tying stand that displayed the tension on a computer. Mean tensions in cerclage wires tied with twist, single loop, or double loop knots were compared. The relationship between level of surgeon experience and tension achieved was examined.

Results—29 twist, 30 single loop, and 16 double loop wires were analyzed. Mean ± SD tension for twist knots was significantly less than for single loop knots (82.3 ± 46.1 vs 166.6 ± 42.2 N, respectively). Double loop knots achieved significantly greater tension (392.0 ± 116.6 N) than twist and single loop knots did, even though few participants had ever tied this knot previously. There was no correlation with experience of the participant. For twist knots, wiggling the wire during cutting and pushing the twist over to flatten it to the bone further reduced tension.

Conclusions and Clinical Relevance—Cerclage applied with a twist knot does not compress fracture fragments as effectively as cerclage applied with single loop or double loop techniques. Because greater compression of fragments will improve the stability of a fracture, a surgeon should strive to maximize the tension in the cerclage that they use. Experience and abilities of the surgeon are not associated with ability to tie cerclage wires tightly. (J Am Vet Med Assoc 2002;220:334–336)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine prevalence of radiographic evidence of degenerative joint disease (DJD) in geriatric cats.

Design—Retrospective study.

Population—100 cats > 12 years of age.

Procedure—One investigator reviewed radiographs and for each articulation (or group of articulations) that was visible assigned a grade of severity (0, 1, 2, 3) for DJD. Another investigator reviewed medical records and recorded signalment, environment, previous disease, diseases evident at time of radiography, FeLV vaccination and infection status, feline immunodeficiency virus serologic status, serum creatinine concentration, serum globulin concentration, and any other important findings. Associations between DJD of grade 2 or 3 and variables recorded from the medical record were determined.

Results—Radiographic evidence of DJD was evident in 90% of cats. Neurologic disease was associated with lesions in the lumbosacral portion of the vertebral column. Severe lesions were found in 17% of the elbow joints, but an underlying cause was not determined.

Conclusions and Clinical Relevance—Degenerative joint disease was detected radiographically in most geriatric cats and may be an overlooked cause of clinical disease. Clinicians should be alert to the possibility that DJD is associated with neurologic signs. (J Am Vet Med Assoc 2002;220:628–632)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare application time, accuracy of tibial plateau slope (TPS) correction, presence and magnitude of rotational and angular deformities, and mechanical properties of 5 canine tibial plateau leveling methods.

Sample Population—27 canine tibial replicas created by rapid prototyping methods.

Procedure—The application time, accuracy of TPS correction, presence and magnitude of rotational and angular deformation, and construct axial stiffness of 3 internal fixation methods (tibial plateau leveling osteotomy, tibial wedge osteotomy, and chevron wedge osteotomy [CWO]) and 2 external skeletal fixation (ESF) methods (hinged hybrid circular external fixation and wedge osteotomy linear fixation [WOLF]) were assessed.

Results—Mean bone model axial stiffness did not differ among methods. Mean application time was more rapid for WOLF than for other methods. Mean TPSs did not differ from our 5° target and were lower for ESF methods, compared with internal fixation methods. Mean postoperative rotational malalignment did not differ from our target or among groups. Mean postoperative medio-lateral angulation did not differ from our target, except for CWO. Internal fixation methods lead to axially stiffer constructs than ESF methods. Reuse of ESF frames did not lead to a decrease in axial stiffness.

Conclusions and Clinical Relevance—The 5 tibial plateau leveling methods had acceptable geometric and mechanical properties. External skeletal fixation methods were more accurate as a result of precise data available for determining the exact magnitude of correction required to achieve a 5° TPS.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare an electron beam melting-processed (EBMP) low-modulus titanium alloy mesh stem with a commercial cobalt-chromium (CC) stem in a canine cadaver model.

Sample Population—9 pairs of cadaver femora.

Procedures—EBMP stems of 3 sizes were placed in randomly chosen sides of femora (left or right) and CC stems in opposite sides. Stem impaction distances were recorded. Five strain gauges were attached to the femoral surface to record transverse tensile (hoop) strains in the femur during axial loading. Constructs were axially loaded 4 times to 800 N and 4 times to 1,600 N in a materials testing machine. Axial stiffness of constructs and bone surface strains were compared between EBMP and CC constructs.

Results—Stems were impacted without creating femoral fissures or fractures. Stem impaction distances were larger for EBMP stems than for CC stems. Mean axial stiffness of EBMP constructs was lower than mean axial stiffness of CC constructs. Subsidence did not differ between groups. Bone strains varied among strain gauge positions and were largest at the distal aspect of the stems. At a load of 1,600 N, bones strains were higher in CC constructs than in EBMP constructs for 2 of 4 medial strain gauges.

Conclusions and Clinical Relevance—EBMP stems were successfully impacted and stable and led to a focal decrease in bone strain; this may represent an acceptable option for conventional or custom joint replacement. (Am J Vet Res 2010;71:1089–1095)

Although cemented hip stems have been used successfully as part of total hip replacements in humans, their success rate has been reportedly lower in younger patients than in older patients. The longterm success of hip stems is affected by aseptic implant loosening, implant wear, and stress-mediated bone resorption (stress shielding). Cementless hip stems were originally developed in part because polymethylmethacrylate bone cement was considered to be a contributing factor to aseptic loosening of cemented hip stems. A portion of a cementless stem is textured or coated with porous surfaces for bone ongrowth and ingrowth. Stem stability relies on initial press fit and long-term bone ingrowth into the porous portions of the stems. Cementless stems are large and have a high

Full access
in American Journal of Veterinary Research

Abstract

Objective—To test the effects of bone diameter and eccentric loading on fatigue life of 2.7-mm-diameter cortical bone screws used for locking a 6-mm-diameter interlocking nail.

Sample Population—Eighteen 2.7-mm-diameter cortical bone screws.

Procedure—A simulated bone model with aluminum tubing and a 6-mm-diameter interlocking nail was used to load screws in cyclic 3-point bending. Group 1 included 6 screws that were centrally loaded within 19-mm-diameter aluminum tubing. Group 2 included 6 screws that were centrally loaded within 31.8-mmdiameter aluminum tubing. Group 3 included 6 screws that were eccentrically loaded (5.5 mm from center) within 31.8-mm-diameter aluminum tubing. The number of cycles until screw failure and the mode of failure were recorded.

Results—An increase in the diameter of the aluminum tubing from 19 to 31.8 mm resulted in a significant decrease in the number of cycles to failure (mean ± SD, 761,215 ± 239,853 to 16,941 ± 2,829 cycles, respectively). Within 31.8-mm tubing, the number of cycles of failure of eccentrically loaded screws (43,068 ± 14,073 cycles) was significantly greater than that of centrally loaded screws (16,941 ± 2,829 cycles).

Conclusions and Clinical Relevance—Within a bone, locking screws are subjected to different loading conditions depending on location (diaphyseal vs metaphyseal). The fatigue life of a locking screw centrally loaded in the metaphyseal region of bone may be shorter than in the diaphysis. Eccentric loading of the locking screw in the metaphysis may help to improve its fatigue life. (Am J Vet Res 2003;64:569–573)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare synovial fluid biomarkers of cartilage metabolism in joints with naturally acquired or experimentally induced cranial cruciate ligament (CCL) rupture and determine correlations with stage and severity of disease in dogs.

Animals—95 dogs with ruptured CCL, 8 dogs with experimentally ruptured CCL, and 24 healthy dogs.

Procedure—Synovial fluid was assayed for chondroitin sulfate neo-epitopes 3B3(–) and 7D4 and glycosaminoglycan (GAG) concentration. Results were correlated with demographic data, duration of lameness, radiographic osteoarthritis score, and intra-articular lesions.

Results—The 7D4 concentrations and 7D4:GAG in synovial fluid from joints with naturally acquired CCL rupture and experimental CCL transection were similar and significantly greater than values for healthy control joints. The 3B3(–) concentrations in the CCL-deficient groups were not significantly different, although only values in the naturally acquired CCL rupture group were significantly greater than those in the healthy control group. Within the naturally acquired CCL rupture group there was a significant correlation between 3B3(–) and 7D4 concentrations. However, there were no significant correlations between biomarker concentrations and continuous demographic or diseaserelated variables or differences in biomarker concentrations with different categories of disease.

Conclusion and Clinical Relevance—Synovial fluid biomarker concentrations were significantly increased in joints with secondary osteoarthritis associated with naturally acquired or experimental CCL rupture; however, lack of apparently simple relationships with demographic variables or stage or severity of disease limits their clinical usefulness. (Am J Vet Res 2002;63:775–781)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare measurements obtained by use of a universal plastic goniometer (UG) and an electrogoniometer (EG) and from radiographs and to compare joint motion in German Shepherd Dogs and Labrador Retrievers.

Animals—12 healthy adult German Shepherd Dogs and data previously collected from 16 healthy adult Labrador Retrievers.

Procedures—German Shepherd Dogs were sedated. One investigator then measured motion of the carpal, cubital (elbow), shoulder, tarsal, stifle, and hip joints of the sedated dogs. Measurements were made in triplicate with a UG and an EG. Radiographs were taken of all joints in maximal flexion and extension. Values were compared between the UG and EG and with values previously determined for joints of 16 Labrador Retrievers.

Results—An EG had higher variability than a UG for all dogs. The EG variability appeared to result from the technique for the EG. German Shepherd Dogs had lower values in flexion and extension than did Labrador Retrievers for all joints, except the carpal joints. German Shepherd Dogs had less motion in the tarsal joints, compared with motion for the Labrador Retrievers, but had similar motion in all other joints.

Conclusions and Clinical Relevance—A UG is reliable for obtaining measurements in German Shepherd Dogs. There was higher variability for the EG than for the UG, and an EG cannot be recommended for use.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effects of fascial abrasion, fasciotomy, and fascial excision on cutaneous wound healing in cats.

Animals—Eight 1- to 3-year-old domestic shorthair cats.

Procedures—8 evenly spaced 4-cm2 skin wounds were created on each cat's dorsum, and the underlying subcutaneous tissue was removed to expose the epaxial muscle fascia. Wounds were randomized to receive 1 of 4 treatments (2 wounds/treatment/cat): fascial abrasion, fasciotomy, fascial excision, or control treatment (muscle fascia not disturbed). Bandages were changed and digital photographs and acetate tracings of the wounds were obtained for planimetry daily for 1 week, every other day for 2 weeks, and then every third day for 3 weeks (ie, 40-day observation period). Digitized images were evaluated for granulation tissue formation, wound contraction (surface area measurements), and area of epithelialization.

Results—The epithelialized area and open and total wound areas did not differ among treatments at any time point. Time to the first appearance of granulation tissue was significantly shorter for all treatment groups, compared with that of the control group. Time to achieve granulation tissue coverage of wound base was significantly shorter following fasciotomy (9.6 days) and fascial excision (9.0 days), compared with that of control treatment (18.5 days) or abrasion (16.7 days). Numbers of wounds that developed exuberant granulation tissue following fascial excision (9/16) and control treatment (3/16) differed significantly.

Conclusions and Clinical Relevance—Fasciotomy and fascial excision facilitated early granulation tissue development in cutaneous wounds in cats. In clinical use, these fascial treatments may expedite secondary wound closure or skin grafting.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate the safety and efficacy of oral administration of the serotonin antagonist and reuptake inhibitor trazodone hydrochloride to facilitate confinement and calming after orthopedic surgery in dogs.

Design—Prospective open-label clinical trial.

Animals—36 client-owned dogs that underwent orthopedic surgery.

Procedures—Starting the day after surgery, dogs were administered trazodone (approx 3.5 mg/kg [1.6 mg/lb], PO, q 12 h) with tramadol (4 to 6 mg/kg [1.8 to 2.7 mg/lb], PO, q 8 to 12 h) for pain management. After 3 days, administration of tramadol was discontinued, and the trazodone dosage was increased (approx 7 mg/kg [3.2 mg/lb], PO, q 12 h) and maintained for at least 4 weeks. If needed, trazodone dosage was increased (7 to 10 mg/kg [3.2 to 4.5 mg/lb], PO, q 8 h). Owners completed electronic surveys rating their dogs’ confinement tolerance, calmness or hyperactivity level, and responses to specific provocative situations prior to surgery and 1, 2, 3, and 4 weeks after surgery and at the postsurgery evaluation (at 8 to 12 weeks).

Results—Most (32/36 [89%]) of owners reported that their dogs, when given trazodone during the 8 to 12 weeks following orthopedic surgery, improved moderately or extremely with regard to confinement tolerance and calmness. Trazodone was well tolerated, even in combination with NSAIDs, antimicrobials, and other medications; no dogs were withdrawn from the study because of adverse reactions. Owner-reported median onset of action of trazodone was 31 to 45 minutes, and median duration of action was ≥ 4 hours.

Conclusions and Clinical Relevance—Results suggested that oral administration of trazodone was safe and efficacious and may be used to facilitate confinement and enhance behavioral calmness of dogs during the critical recovery period following orthopedic surgery.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare ground reaction forces (GRFs) measured by use of a pressure-sensitive walk-way (PSW) and a force plate (FP) and evaluate weekly variation in the GRFs and static vertical forces in dogs.

Animals—34 clinically normal dogs and 5 research dogs with lameness.

Procedure—GRF data were collected from 5 lame and 14 clinically normal dogs by use of an FP and a PSW. Peak vertical force (PVF), vertical impulse (VI), and velocity measurements (determined by use of photocells and PSW data) were compared between groups. Peak vertical force, VI, stride length, ground phase time (ie, contact time), and static body weight distribution data were collected on 2 occasions, 1 week apart, in 20 different clinically normal dogs by use of a PSW; week-to-week variation in values was evaluated.

Results—Measurements of velocity derived by use of the photocells were not different from those derived by use of the PSW. For any 1 limb, values derived by use of the PSW were significantly lower than values derived with the FP. For values obtained by use of either technique, there were no differences between left and right limbs except for values of PVF measured via PSW in forelimbs. Values of PVF, VI, contact time, stride length, and static weight distribution generated by the PSW did not vary from week to week.

Conclusions and Clinical Relevance—Values for GRFs varied between the FP and PSW. However, data derived by use of PSW were consistent and could be used to evaluate kinetic variables over time in the same dog.

Full access
in American Journal of Veterinary Research