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Competing Interests: None declared.

Teaching the art of wire tying is difficult because the instructor is not able to gauge the effectiveness of the final product. The impact of an incorrect technique is usually not evident. Also, the instructor does not have a way to demonstrate the different levels of tension generated by different wire knotting techniques, nor their differing abilities to resist a load that a patient may apply. In this paper, a device is described that can provide real-time feedback on wire tension generated during knot tying, and how particular knots resist an applied distraction. This device has been used to deliver a live demonstration to reinforce lecture material, and in small group teaching exercises, where real-time feedback enhances skills and understanding. A stepwise training schedule for surgery residents structured as an entrustable professional activity is proposed.

Objective: To compare the mechanical performance of cerclage secured with twist, single-loop, and double-loop knots subjected to cyclic loading., Study Design: In vitro biomechanical study., Sample Population: Twist, single-loop and double-loop cerclage configurations of 1.0 mm wire., Methods: The peak load resisted by each cerclage type was determined (n = 6). Cerclage were loaded cyclically to 80%, 60%, 40%, or 20% of its peak load (n = 8 per load level). The number of cycles until each cerclage loosened (residual tension <10 N) was recorded., Results: All wires that failed did so by loosening. Twist cerclage cycled to 390 N and 290 N loosened within the first 10 cycles, and, when cycled to 100 N, they loosened by 250 cycles. All twist knots loosened by untwisting. Single-loop cerclage cycled to 320 N loosened within 10 cycles. At 240 N, 5 single-loop cerclage resisted 250 cycles before loosening. At 160 N, 2 of the 8 single-loop cerclage did not loosen by 100 000 cycles. When cycled to 640 N, one of the double-loop cerclage did not loosen following 500 000 cycles. When cycled to 480 N, 3 of the 8 wires did not loosen., Conclusion: Double-loop cerclage will be tighter and are better able to resist cycling than twist or single-loop cerclage., Clinical Significance: Use of double-loop cerclage to stabilize bone fragments or prevent fissure propagation can be expected to provide greater resistance to loosening than twist or single-loop cerclage, both initially and with repeated loading., (© 2021 American College of Veterinary Surgeons.)

Background: This study aimed to define the rate of progression of radiographic osteoarthritis (OA) of the canine hip joint and to describe factors affecting this progression., Methods: Dogs that underwent unilateral total hip replacement (THR) were reviewed for the evaluation of radiographic appearance of the non-operated hip joint over time. Standard extended ventrodorsal hip radiographs were taken preoperatively and postoperatively. All images were anonymized, randomized and scored using three different methods. The mean daily change between evaluations was calculated in each individual dog, and the effect of sex, age, body weight, open/closed status of the proximal femoral physis, preoperative severity of OA, time after surgery and their interactions, were investigated as potential influencing factors., Results: After reviewing the medical records, 163 dogs (468 images) met the inclusion criteria. Consistent across the three scoring systems, radiographic progression of OA was greater in younger (open physis) and spayed female dogs. A subset of seven patients (4.3%) had a faster progression of OA and was considered outliers. No dog was rated as outlier by all three scoring systems., Conclusion: The rate of progression of radiographically assessed coxofemoral OA varies greatly, but is faster in younger, spayed female dogs. Unusually fast progression occasionally occurs., (© 2021 British Veterinary Association.)

Audience response devices are useful tools that can improve student engagement and learning during instructional sessions. The purpose of this article is to describe our experience with a new cloud-based application known as Top Hat, which includes audience response tools in its application suite. The software was used in a multi-specialty, multi-instructor medicine and surgery course in the third year of a veterinary curriculum. In addition to standard multiple-choice and short-answer questions, Top Hat has several unique question types and methods of displaying the responses given. These include displaying free-text responses in a word cloud format and a "click-on-target" question type that allows students to indicate their response by clicking on a location within an image. Responses for this latter question type are displayed in a heat map format. A discussion tool is also available, which allows students to respond, read other students' responses in real time, and then reply again if warranted. This feature also supports drawing-based responses. The variety of question types was very useful in keeping students engaged during teaching sessions, giving this application several advantages over systems that are limited to multiple-choice questions only. In addition, the application allowed rapid identification of areas of student knowledge and misunderstandings, which facilitated the direction of further discussion and clarification of important learning issues.

Objective: To determine the influence of wiring configurations on initial tension and resistance to tensile loads in tension band constructs without the contributions of Kirschner-wire stabilization., Study Design: Experimental study., Sample Population: A solid brass femur model manufactured on the basis of computed tomography of a normal right femur of a 30-kg dog modified by transection of the greater trochanter and placement of two pins that did not cross the simulated osteotomy., Methods: Four tension band configurations were applied to the metal trochanteric osteotomy model: figure-of-eight with one twist (OT), figure-of-eight with two twists (TT), dual interlocking single loop, and double loop (DL). Configurations were tested under both monotonic loading (n = 8 per configuration) and incremental cyclic loading (n = 8 per configuration). Initial tension after tying, residual tension remaining after each cycle, and failure load at 2 mm of displacement (considered equivalent to clinical failure) were compared between configurations., Results: The initial tension and the load to 2 mm of displacement were lower for OT wires compared with TT wires. The DL was the strongest and most stable configuration, generating 2.3 to 3.5 times greater initial tension, maintaining a greater percentage of residual tension under incremental cyclic loads, and resisting 2.0 to 2.4 times greater load before failure at 2 mm. Failure load was highly correlated with initial tension., Conclusion: Wire configurations reaching greater initial tension, such as the DL, allowed constructs to resist higher tensile loads., Clinical Impact: Wire configurations allowing higher initial tension may be warranted when tension bands are expected to sustain high tensile loads., (© 2019 The American College of Veterinary Surgeons.)

Objectives:  To evaluate the influence of radiographic malpositioning on canine sacroiliac and lumbosacral inclination angles., Methods:  Using canine cadavers, lateral pelvic radiographs were acquired with the radiographic beam in a neutral position and then rotated 5, 10 and 15° to mimic rotational malpositioning. The focal point of the beam was then focused over the abdomen and again over mid-diaphysis of the femur to mimic an abdominal or femoral radiographic study., Results:  Five degrees of rotational malpositioning did not influence measurements of sacroiliac or lumbosacral inclination, but malpositioning by more than 5° led to a significant decrease in both sacroiliac and lumbosacral angles. Moving the focal point to the femur significantly decreased the measured lumbosacral angle. Abdominally centred radiographs had no effect on lumbosacral and sacroiliac angle measurements., Clinical Significance:  When evaluating canine lumbosacral and sacroiliac angles radiographically, pelvic rotation of more than 5° should be avoided as should the use of lateral radiographs centred over the femur., Competing Interests: Conflicts of Interest: The authors declare that they have no conflicts of interest with regard to this manuscript., (Schattauer GmbH Stuttgart.)

Objective: To evaluate the accuracy and repeatability of measurements collected using a weight distribution platform and a pressure sensitive walkway using an inanimate object with known weight distribution., Methods: A custom-built jig with a range of weights was applied in a random order. Measurements were collected on both devices and compared to each other and to the known weight distribution., Results: Weight distribution platform and pressure sensitive walkway measurements were highly correlated to each other (Pearson's correlation coefficient R = 0.98) and to actual weights (R = 0.99 for the weight distribution platform; 0.98 for the pressure sensitive walkway). Repeatability from day to day for both devices was greater than 0.99. For the weight distribution platform, the 95% confidence interval was ± 2.5% from the true percentage and ± 3.3% for the pressure sensitive walkway. The coefficient of variation (COV) was highest for both devices at the lightest weights (weight distribution platform 11.28%, pressure sensitive walkway 16.91%) and lowest with the heaviest weights (weight distribution platform 3.71%, pressure sensitive walkway 5.86%)., Conclusion: Both the weight distribution platform and the pressure sensitive walkway provided accurate and consistent measures of weight distribution with no significant difference between devices. The rounded standard error was three percent for the weight distribution platform, and four percent for the pressure sensitive walkway. The higher variability when measuring the smallest weight suggests less accuracy at lower weights with both devices., Clinical Significance: The weight distribution platform is a repeatable and accessible device to measure static weight distribution, and if proven the same in a clinical setting, it will be a valuable addition to current objective measures of limb use.

Objective: To evaluate the effect of contouring a tibial plateau leveling osteotomy (TPLO) plate, the associated angulation of the dynamic compression plate (DCP) hole relative to the long axis of the tibia, and angulation of the screw relative to the DCP hole on the osteotomy compression generated by load screws in a TPLO model., Study Design: In vitro biomechanical study., Study Population: Polyoxymethylene (POM) rod and synthetic cortical bone substitute model (n = 9)., Methods: The distal portion of a Slocum TPLO plate was attached to a horizontally positioned POM rod that was connected to a load cell. A segment of synthetic cortical bone substitute was attached to the end mount of the testing frame and adjusted to conform to the angle of the proximal portion of the TPLO plate. A 3.5 mm cortical bone screw was inserted in the proximal DCP hole and tightened to 1.5 Nm. The peak longitudinal load (N) was recorded. Screw insertion and data collection were repeated for proximal plate angles of 0-40° at 5° increments., Results: A significant increase in the compression generated was observed as the plate angle was increased from 0° to 10°. The compression ceased to significantly increase until the plate was bent more than 20°, after which a significant decrease in compression was noted. A marked reduction in the compression generated occurred at plate angles greater than 30°., Conclusion: Angulation of the DCP hole and screw insertion angle can have deleterious effects on the magnitude of osteotomy compression., (© Copyright 2015 by The American College of Veterinary Surgeons.)

OBJECTIVE To assess intraobserver repeatability and interobserver and in vivo versus photographic agreement of a scoring system for the implant-skin interface (ISI) of external skeletal fixation (ESF). SAMPLE 42 photographs of ISIs from 18 dogs for interobserver agreement and intraobserver repeatability and 27 photographs of ISIs from 6 dogs for in vivo versus photograph agreement. PROCEDURES An ISI inflammation scoring system was developed. It included scales for 6 metrics (erythema, drainage amount, drainage type, swelling, hair loss or lack of hair regrowth, and granulation tissue). Photographs of the ISI of ESF were obtained by use of a standard protocol and evaluated to determine intraobserver repeatability and interobserver agreement (Cronbach α; 4 raters) of the ISI score. Agreement between in vivo and photographic ISI scores (2 raters) and correlation between median scores across metrics were evaluated. RESULTS 42 photographs met the inclusion criteria. Overall intraclass correlation coefficients ranged from 0.922 to 0.975. Interobserver overall Cronbach α ranged from 0.835 to 0.943. For in vivo versus photographic assessment, 27 ISIs in 6 dogs and their photographs were evaluated. The Cronbach α for both raters ranged from 0.614 to 0.938. Overall, the Cronbach α ranged from 0.725 to 0.932. Mean photographic scores were greater than mean in vivo scores for each metric. Pearson correlation coefficients ranged from 0.221 to 0.923. Erythema, swelling, and granulation were correlated with all other metrics. CONCLUSIONS AND CLINICAL RELEVANCE In this study, an ISI scoring system used in this study had high repeatability and agreement and may therefore be considered for use in clinical situations. Photographic scores were not equivalent to in vivo scores and should not be used interchangeably.

Component malalignment and impingement are possible causes of recurrent luxation following total hip replacement in the dog. In the two cases presented in this report, luxation that was probably due to impingement was managed by exchanging the standard 17 mm prosthetic head for a 24 mm prosthetic head. This required removal of the original acetabular cup liner and placement of a new polyethylene liner that would accept the 24 mm head into the stable acetabular shell. In the first case, a 50 kg Malamute dog, recurrent luxation was initially managed by component alignment revision, iliofemoral suture, triple pelvic osteotomy and a novel lasso technique, without long-term success. After exchanging the head and cup liner, luxation did not recur over a 12-month period. In the second case, a 65 kg Newfoundland dog, impingement was suspected after a second luxation event. Luxation did not recur during the nine months after exchange of the head and cup liner. The larger prosthetic head used in these two cases increased the impingement-free range-of-motion of the joint and increased the translation distance required for luxation (jump distance).

Objectives: To evaluate the patellar ligament to tibial plateau angle (PL-TPA) and amount of achieved advancement in dogs that underwent the modified Maquet procedure; compare wedge sizes recommended using two different planning techniques (Orthomed and modified tibial tuberosity advancement); and evaluate anatomical factors that predict the wedge size required to obtain a 90° PL-TPA., Methods: Pre- and postoperative radiographs of dogs that had a modified Maquet procedure performed were evaluated for the following: calculated wedge size using two different planning techniques, the actual wedge size used, the achieved tibial tuberosity advancement, and the changes in PL-TPA. Anatomical measurements of the tibia were evaluated and correlated with the actual wedge size., Results: Of the 38 modified Maquet procedures identified, 53% (n = 20) had a PL-TPA of 90° ± 5°. Actual achieved advancement of the tibial tuberosity was 30% less than the wedge size used. Changes in PL-TPA and tibial width persisted at eight weeks postoperatively without loss of advancement. The two planning techniques did not result in a significantly different selection of wedge size., Clinical Relevance: Current planning techniques for the modified Maquet procedure result in under-advancement of the tibial tuberosity. Both measurement techniques evaluated do not result in appropriate advancement.

A Helica short-stemmed femoral prosthesis that was identified as being loose one year after implantation was revised with a standard long stem cementless BFX femoral prosthesis. A double pelvic osteotomy was also performed to improve the orientation of the stable acetabular cup. Despite complete resorption of the femoral neck, and a large perforation of the lateral femoral cortex, the revision stem did not subside or rotate. The prosthetic joint did not dislocate. At re-evaluation two years after revision surgery, the prosthetic components were stable. Signs of bone ingrowth into the stem and cup were evident on radiographs. The dog had a seven percent greater thigh muscle girth in the limb implanted with the hip prosthesis compared to the contralateral limb, and was very active with no lameness.

Objective: Evaluate variability associated with assessing changes in the position of uncemented femoral stems., Methods: Stem level, canal fill, stem angle, and version angle were measured on craniocaudal horizontal beam (CCHB) and open leg lateral (OLL) radiographic projections of the femur of 20 dogs that had uncemented total hip replacement. Intraobserver and interobserver repeatability were determined on immediate postoperative (PO) images. Differences in position were calculated between the first (3 months - R1) and second (6 months - R2) re-evaluation (R1-R2) time points, and between PO and R1., Results: The measurement process was very repeatable. For R1-R2, the stem appeared to subside 0.8 ± 1.4 mm for measurements based on the greater trochanter on the CCHB images, but there was a wide range (-3.9 to 2 mm; positive values indicate proximad movement). Measurements based on the intertrochanteric crest on the OLL images had the same mean, and also a wide range (-4.4 to 2.1 mm; negative values indicate proximad movement). For PO-R1, the stem appeared to subside 1.8 ± 2.0 mm (CCHB, based on the greater trochanter, range -7.7 to 2.2 mm), 1.6 ± 1.5 mm (CCHB, based on the intertrochanteric crest, range -0.7 to 4.3 mm); and 2.1 ± 2.1 mm (OLL, based on the intertrochanteric crest, range -1.6 to 6.8 mm)., Conclusion: The position of a stable stem can appear different on subsequent re-evaluations, but this may be due to variability associated with inconsistency of positioning of the patient and limb., Clinical Significance: Documenting subsidence in individual patients should not rely on calculations based on a single measurement.

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.

Objectives: To compare von Frey mechanical quantitative sensory thresholds (mQSTvF ) between pelvic limbs in dogs before unilateral total hip replacement (THR) surgery; to correlate ground reaction forces (GRF) with mQSTvF ; to assess changes in mQSTvF after THR surgery., Study Design: Prospective clinical study., Animals: Dogs (n = 44)., Methods: mQSTvF and GRF measured using a pressure sensitive walkway were evaluated before, and 3, 6, and 12 months after, unilateral THR. Measurements were recorded from the affected (operated) pelvic limb (APL) and the non-operated pelvic limb (NPL). Random effects analysis and forwards stepwise linear regression models were used to evaluate the influence of time since surgery and patient factors on mQSTvF thresholds., Results: There were no significant correlations between mQSTvF data and age, bodyweight or the GRF variables. Preoperative mQSTvF measured at the APL and NPL did not differ (P = .909). mQSTvF thresholds increased significantly after 12 months in NPL (P = .047) and APL (P = .001). In addition to time, APL mQSTvF values were significantly affected by sex (higher in males, P = .010) and body condition score (higher in leaner dogs, P = .035) and NPL mQSTvF values by sex (P = .038)., Conclusion: Successful unilateral THR results in decreased central sensitization after 12 months., (© Copyright 2014 by The American College of Veterinary Surgeons.)

Objective: To compare the mechanical properties of feline ilial fractures stabilized with either a plate (P), or a plate and IM pin (P + P)., Study Design: Mechanical study., Sample Population: Cadaveric cat pelvii (n = 10)., Methods: Feline ilial fractures (n = 20) stabilized with either P or P + P were subjected to 100 nondestructive load cycles, then loaded to failure. Deformation after cycling, yield load and displacement, stiffness and load at 2 mm of displacement were compared between groups., Results: There were no significant differences between groups for any of the parameters. Variability of data was much larger for the P + P group., Conclusions: No biomechanical advantage was demonstrated. The P + P constructs were not significantly stronger than plates alone in this acutely loaded cadaveric model., (© Copyright 2013 by The American College of Veterinary Surgeons.)

Objective: To determine whether there is a difference between the ability of peak vertical force (PVF), vertical impulse (VI), and percentage body weight distribution (%BW(dist) ) in differentiating which leg is most affected by hip joint pain before total hip replacement (THR) surgery, and for measuring changes in limb use after THR surgery., Study Design: Prospective clinical study., Animals: Dogs (n = 47)., Methods: Ground reaction force (GRF) data were collected using a pressure-sensitive walkway the day before THR surgery and at ∼3, 6, and 12 months postoperatively. PVF and VI expressed as a percentage of body weight (%PVF, %VI), and %BW(dist) were recorded. Regression models performed separately for each outcome were used for statistical analysis., Results: When comparing limb use between the affected limb (AP) and the nonaffected limb (NP) preoperatively, differences between limbs were statistically significant when evaluated using PVF (P = .023), VI (P = .010), and %BW(dist) (P = .012). When evaluating the magnitude of absolute and percentage change difference in AP limb use preoperatively versus postoperatively, differences were statistically significant when evaluated using PVF (P < .001 and P = .001, respectively), VI (P = .001 and P < .001) and %BW(dist) (P < .001 and P < .001)., Conclusion: There appeared to be no difference in the sensitivity of VI, PVF, and %BW(dist) for evaluating limb use before and after THR., (© Copyright 2012 by The American College of Veterinary Surgeons.)

Objective: To compare: (1) the force required to initiate subsidence, and (2) the relative subsidence, of femoral stems implanted into intact femora, and then into the same femora in which an induced fissure had been stabilized by cerclage., Study Design: In vitro, mechanical study., Sample Population: Femora (n=9) from 9 dogs., Methods: Femora were prepared for implantation of an uncemented stem. Stems were implanted with continuous and impact loading. After axial loading until a fissure occurred, the stems were extracted, and the fissure stabilized with double-loop cerclage. Stems were reimplanted, and reloaded to failure., Results: Mean±SD load to initiate subsidence in intact femora was 1706±584 N compared with 2379±657 N for cerclaged bones (P=.002). Mean relative subsidence of intact femora was 3.99±2.09 mm compared with 1.79±2.99 mm for cerclaged bones (P=.091)., Conclusions: The load to initiate subsidence is increased in femora that have fissured, then have been stabilized with double-loop cerclage, when compared with intact femora. The relative subsidence is not different between intact and stabilized specimens., (© Copyright 2011 by The American College of Veterinary Surgeons.)

Present recommendations regarding order of screw insertion for compression plate osteosynthesis in veterinary training are variable. We hypothesized that placement of a neutrally positioned screw would reduce the magnitude of compression that could be generated by a subsequently placed compression screw. Canine tibial diaphyseal segments were fixed to a plate attached to a bone surrogate and load cell, and the compression generated by screw tightening was measured. Three different screw insertion order patterns were evaluated using both dynamic compression plate (DCP) and limited contact dynamic compression plate (LC-DCP) implants. In group CN, the first screw was placed in compression mode and the second in neutral mode; in group NC, the first screw was placed in neutral mode and the second in compression mode; in group LNC, the first screw was placed partially tightened in neutral mode and the second in compression mode followed by complete tightening of the neutral screw. Screw insertion order significantly influenced the amount of compression generated with both groups CN and LNC demonstrating significantly greater compression generation when compared with group NC (p <0.0001). Compression generated by group CN constructs was also significantly greater than group LNC (p = 0.0013). Evaluation of group CN data to assess the influence of plate and drill guide combinations on compressive force generated did not demonstrate a statistically significant difference. To maximize compression using a load screw in a bone plate, following securement of the opposite bone fragment to the plate, it should be placed before a neutral screw is placed.

Objective: To determine the items (question topics) for a subjective instrument to assess degenerative joint disease (DJD)-associated chronic pain in cats and determine the instrument design most appropriate for use by cat owners., Animals: 100 randomly selected client-owned cats from 6 months to 20 years old., Procedures: Cats were evaluated to determine degree of radiographic DJD and signs of pain throughout the skeletal system. Two groups were identified: high DJD pain and low DJD pain. Owner-answered questions about activity and signs of pain were compared between the 2 groups to define items relating to chronic DJD pain. Interviews with 45 cat owners were performed to generate items. Fifty-three cat owners who had not been involved in any other part of the study, 19 veterinarians, and 2 statisticians assessed 6 preliminary instrument designs., Results: 22 cats were selected for each group; 19 important items were identified, resulting in 12 potential items for the instrument; and 3 additional items were identified from owner interviews. Owners and veterinarians selected a 5-point descriptive instrument design over 11-point or visual analogue scale formats., Conclusions and Clinical Relevance: Behaviors relating to activity were substantially different between healthy cats and cats with signs of DJD-associated pain. Fifteen items were identified as being potentially useful, and the preferred instrument design was identified. This information could be used to construct an owner-based questionnaire to assess feline DJD-associated pain. Once validated, such a questionnaire would assist in evaluating potential analgesic treatments for these patients.

Objective: To evaluate a technique for midhumeral peripheral nerve blockade in the dog., Study Design: Cadaveric technique development; in vivo placebo-controlled, prospective crossover study., Animals: Canine cadavers (n=38) and 8 clinically healthy, adult hound dogs., Methods: A technique for peripheral block of the radial, ulnar, musculocutaneous, and median nerves (RUMM block) was evaluated using cadaver limbs. Eight purpose-bred, research dogs were anesthetized; a RUMM block was performed on each thoracic limb. One limb from each dog randomly received 0.5% bupivacaine and the opposite limb was assigned to receive sterile saline solution as a control. After recovery from anesthesia, skin sensation at selected dermatomes was evaluated for 24 hours using a mechanical stimulus. Weight-bearing, conscious proprioception, and withdrawal reflex were also evaluated. One month after initial testing, each dog was reanesthetized and each limb received the opposite treatment., Results: Sensory thresholds were significantly increased over baseline measurements when compared with control limbs for all nerves. Complete sensory block was achieved in radial (15/16), ulnar (3/16), musculocutaneous (8/16), and median (11/16) nerves, using a mechanical stimulus of analgesia. Complete simultaneous block of all nerves was only obtained in 1 of 16 limbs., Conclusion: RUMM block resulted in desensitization of the skin in the associated dermatomes for 4-10 hours. Complete sensory block of the dermatomes supplied by the radial nerve was most consistent., Clinical Relevance: RUMM block may be an effective technique to provide adjunctive analgesia for dogs undergoing surgery of the distal aspect of the thoracic limb., (© Copyright 2010 by The American College of Veterinary Surgeons.)

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.

Objective: To evaluate stance phase limb use after cementless (BFX) total hip replacement (THR) in dogs and to relate postoperative radiographic variables to static bodyweight distribution after surgery., Study Design: Prospective clinical study., Animals: Dogs (n=35) that had THR., Methods: THR was performed using the BFX THR technique. Postoperative pain management regimens were similar for all dogs. Standing bodyweight distribution (%BW(distrib)) was measured using a pressure sensitive walkway and radiographs made before surgery and at 3, 6, and 12 months after surgery. Repeated measures models (with backwards-stepping to obtain the final model) were used for statistical analysis., Results: Temporally, %BW(distrib) to the operated limb increased (P<.0001; normal by 3 months) and decreased to the unoperated limb (P=.0001) and also increased to the pelvic limbs and decreased to the thoracic limbs. %BW(distrib) to the unoperated limb was significantly less than the operated limb at 3, 6, and 12 months after surgery. Postoperative canal fill and femur flare were significantly negatively correlated with change in %BW(distrib) (estimate=-0.24, P=.0413)., Conclusion: BFX THR results in normal %BW(distrib) to the operated limb by 3 months after surgery. A greater fill of the proximal femur may be associated with a suboptimal outcome., Clinical Relevance: BFX THR normalizes standing bodyweight distribution dogs with hip osteoarthritis. Objective evaluation of THR outcome and radiographic features may reveal factors that could be improved through changes in prosthesis design or surgical technique.

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-cm(2) 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.

A grossly displaced segmental zygomatic arch fracture with marked ventro-lateral deviation of the left globe was diagnosed in a 3-month-old male German Shepherd dog following a bite injury. The fracture was approached via a modified lateral orbitotomy and a fragment of the lacrimal bone removed. The rostral portion of the fracture was stabilized with a 5-hole 2.0 dynamic compression plate bone plate. The surgical correction achieved sufficient skeletal fixation for proper anatomical reduction of the globe and excellent cosmetic and functional outcomes.

A stifle magnetic resonance (MR) imaging protocol was developed based on the appearance of the cruciate ligaments and menisci in normal dogs. Proton density images were subjectively considered to have the highest likelihood of detecting a meniscal lesion. Following this initial evaluation, the accuracy of high-field MR imaging to detect meniscal tears in dogs was evaluated in 11 dogs suffering from naturally occurring cranial cruciate ligament rupture. Dogs underwent MR imaging of the affected stifle before surgery. MR imaging and surgical findings were assessed independently, and then compared. Five tears of the medial meniscus were correctly diagnosed with MR imaging and 19 normal menisci were accurately characterized as such, based on MR images. In one medial meniscus, changes consistent with meniscal degeneration were seen on MR images but this was not seen at surgery. With regard to the lateral meniscus, one false positive diagnosis of a tear was made and this likely represented a normal variation. One other lateral meniscus had changes consistent with meniscal degeneration but, as with the similar lesion seen in the medial meniscus, this was not confirmed surgically. The global sensitivity of MR imaging for the diagnosis of a meniscal tear was 100% and the specificity was 94%. High-field MR imaging is a reliable method to diagnose meniscal tears preoperatively and this may be useful in selecting the surgical approach to clinically abnormal joints and may decrease the need for arthrotomy.

Objective: To determine differences in bacterial strike-through for materials commonly used to cover the distal aspect of the pelvic limb during operative site preparation., Study Design: Randomized block design; ex vivo model., Animals: Canine cadaveric pelvic limbs (n=40)., Methods: Pelvic limbs (n=40) were randomly assigned to 4 treatment groups: Group 1=Vetrap+sterile Coban; Group 2=latex glove+Vetrap+sterile Coban; Group 3=latex glove+Vetrap+sterile Coban+sterile latex glove+sterile Coban; and Group 4=latex glove+Vetrap+sterile disposable drape+sterile Coban. Limbs were contaminated with a standardized bacterial solution and routinely prepared using the assigned distal leg wrap. Bandages were fluid challenged with a saline (0.9% NaCl) solution-soaked laparotomy sponge for 30 seconds. The wrap surface was sampled for microbial culture before surgical preparation, immediately after, and 60 minutes after applying a sterile leg wrap., Results: Bacterial growth occurred in all Group 1 cultures, 90% of Group 2 cultures, and none of the Group 3 and 4 cultures, 60 minutes after applying the sterile wrap., Conclusion: A distal leg wrap of Vetrap+sterile Coban is not effective in preventing bacterial strike-through., Clinical Relevance: If similar results occur in the live animal, then a sterile impermeable barrier must be incorporated into the distal leg wrap to prevent bacterial strike-through.

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) do not always provide sufficient pain relief in dogs with osteoarthritis (OA)., Hypothesis: The use of amantadine in addition to NSAID therapy will provide improved pain relief when compared with the use of nonsteroidal analgesics alone in naturally occurring OA in dogs., Animals: Thirty-one client-owned dogs with pelvic limb lameness despite the administration of an NSAID., Methods: The study was randomized, blinded, and placebo controlled with parallel groups (days 21-42). On day 0, analgesic medications were discontinued. On day 7, all dogs received meloxicam for 5 weeks. On day 21, all dogs received amantadine (3-5 mg/kg once daily per os) or placebo for 21 days, in addition to receiving meloxicam. Assessments were performed before the study and on days 7, 21, and 42. Primary outcome measures were blinded owner assessments of activity using client-specific outcome measures (CSOM) on days 0, 7, 21, and 42. Data were analyzed by a mixed model approach., Results: For CSOM activity, there was a significant time by treatment effect (P=.009). On the basis of the planned post hoc t-tests of postrandomization means, there was a significant difference between treatment groups on day 42 (P=.030), with the amantadine group being more active., Conclusions and Clinical Importance: In dogs with osteoarthritic pain refractory to an NSAID, physical activity is improved by the addition of amantadine. Amantadine might be a useful adjunct therapy for the clinical management of canine osteoarthritic pain.

For a suture that spans a joint to provide support without limiting range of motion, its attachment points on either side of the joint must remain the same distance from each other from full extension to full flexion. The effect of location of the tibial crest attachment for a fabello-tibial crest suture was studied in seven canine cadaveric stifles. The distance from a fabella marker to each of 11 tibial markers was determined from radiographs of each limb, as it progressed from 150 degrees to 130 degrees , 105 degrees , 90 degrees , 65 degrees and 45 degrees of flexion. The marker locations that were more proximal and cranial on the tibial crest had the least percent change in distance. The effect of anchoring the suture to the femur at a site other than the fabella was investigated using the same radiographs. Five marks were placed in a grid on the caudal portion of the femoral condyle and supracondylar region. The mean percent change in length from each femoral point to the five more proximal and cranial tibial markers was determined. The least change in length occurred for those femoral points located close to the origin of the cranial cruciate ligament. Locations more proximal or cranial resulted in large changes in length, particularly when matched with less ideal tibial locations. Although this study does not directly examine length changes in sutures, it demonstrates that there are some locations for the origin and insertion of an extracapsular suture that are associated with less length change than others, and also forms the basis for future investigations.

Objective: To compare olecranon fragment stability between the classic tension band wire (TBW) technique with the wire placed either in contact with (Arbeitsgemeinschaft für Osteosynthesefragen [AO]), or not in contact with, a Kirschner (K)-wire (AOW) to 2 novel wire patterns: a dual interlocking single loop (DISL) and a double loop (DL)., Study Design: Ex vivo mechanical evaluation on cadaveric bones., Sample Population: Canine ulnae (n=40) with olecranon osteotomies repaired with 2 K-wires and 1 of 4 TBW constructs., Methods: Single load to failure applied through the triceps tendon. Displacement was measured from images captured from digital video. Techniques were compared based on the load resisted when the olecranon fragment was displaced 0.5, 1, and 2 mm., Results: At 0.5 mm of displacement, the DISL construct resisted more load than the AOW construct (505 versus 350 N; P=.05). AO and DL constructs resisted an intermediate load (345 and 330 N, respectively). There was no significant difference between groups at 1 mm of displacement. At 2 mm of displacement, DL (785 N) resisted more load than AO (522 N, P=.01) and AOW (492 N, P=.03) groups., Conclusions: DISL constructs provided similar stability to classic TBW constructs whereas DL constructs were more stable at higher loads., Clinical Relevance: The DL construct is easy to perform, less bulky, and provides comparable fragment stability to standard TBW techniques at functional loads. Surgical method is important for optimal performance of all TBW constructs.

A radiographic study was conducted to evaluate the effect of pelvic rotation and of simulated dorsal acetabular rim (DAR) remodeling on the radiographic appearance of the dorsal acetabular edge (DAE). The DAE is the line connecting the cranial and caudal rims of the acetabulum when viewing a pelvic radiograph made with the dog in the ventrodorsal position with the hind limbs extended. In this study, it was hypothesized that the DAE would change with pelvic rotation and simulated DAR damage. Ventrodorsal radiographs of eight canine pelves were made at 0 degrees, 5 degrees, and 10 degrees of left and right pelvic rotation over its longitudinal axis. These radiographs were repeated following removal of 2, 4, and then 6 mm of bone from the right DAR of each pelvis. The ratio of acetabular width to maximum depth of the DAE was calculated. The area between the DAE and a straight line connecting the cranial and caudal acetabular rims was measured digitally. The DAE depth and area changed with pelvic rotation, and with increasing simulated DAR damage. A linear relationship between the obturator foramina width ratio and pelvic rotation allowed estimation of the degree and direction of pelvic rotation. Equations were developed from the data to assist with the estimation of the amount of DAR remodeling on a clinical radiograph.

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.

Objective: To compare mechanical properties of knotted and crimped nylon loops., Study Design: In vitro mechanical evaluation., Sample Population: Loops of 27 kg-test nylon leader. Single strand-clamped square knot compared with 2 crimp systems. Two strand--self-locking knot compared with 2 crimped loops., Methods: (a) Single pull to failure (n = 10) at 500 mm/min. Initial loop tension (N), peak load (N), peak elongation (mm), stiffness of the linear portion of the curve (N/mm), and failure mode were recorded. (b) Incremental cyclic loading to failure (n = 5)--each loop was cycled 5 times to 100 N at a loading rate of 200 mm/min. Cycling was repeated, with the load increased by 50 N after each set. Elongation (mm), tension remaining (N), and after permanent deformation was present, elongation at 10 N (mm) were measured., Results: Initial tension and stiffness were greater for crimped loops when compared with knotted loops. There were no differences between crimped loops. The self-locking knot elongated more, and was less stiff, when compared with 2 crimped loops. With incremental loading, knotted loops elongated more than crimped loops. The tension remaining in the loop fell below 10 N more quickly for knotted loops compared with crimped loops., Conclusion: Crimped loops are stiffer, and resist both static and cyclic load more effectively before becoming permanently elongated, when compared with knotted loops., Clinical Relevance: Stifle stability will be maintained more effectively by crimped nylon loops when compared with knotted loops.

Objective: To evaluate the mechanical properties of canine median sternotomy closure using double-loop cerclage compared with other commonly used cerclage sternotomy closure patterns., Study Design: Experimental study., Sample Population: Forty canine cadaveric sternal segments., Methods: Median sternotomy-wire constructs were loaded to failure in a materials testing machine. Each construct was radiographed before and after testing. Specific wire configurations tested were: 2 single twist cerclage centered on the sternebrae, single twist figure of 8 pattern centered on the sternal synchondrosis, double twist figure of 8 pattern centered on the sternal synchondrosis, 2 double-loop cerclage centered on the sternebrae, and 1 double-loop cerclage centered on the sternal synchondrosis. Wire configurations were compared by craniocaudal translation of sternabrae on pre-test radiographs, and displacement during loading, and mode of failure, based on analysis of test video, and post-test radiographs., Results: Double-loop cerclage did not provide superior mechanical stabilization of median sternotomy. Both figure of 8 patterns had the least displacement at higher loads. Two single twists that were centered on sternebrae were least able to prevent displacement at higher loads, caused the most craniocaudal translation before testing, and fractured more often at loads < or = 200 N compared with other configurations., Conclusion: Sternal wiring techniques stabilizing sternal synchondroses had the least displacement. Overall, figure of 8 cerclage appeared most suitable because they minimized displacement at high loads and facilitated accurate reduction during tensioning., Clinical Relevance: In closing canine sternotomy, figure of 8 cerclage may be most suitable. Double-loop cerclage centered on the sternal synchondrosis should be avoided because of wire failure at high loads.

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 degrees 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 degrees TPS.

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.

Background: The traditionally used square knot used for commencement and termination of continuous wound closures is bulky, requiring a minimum of four to six throws to form a secure knot with most suture materials and sizes. This study evaluates the security of self-locking knots, which are significantly smaller in volume than the traditionally applied square knot, for the intradermal closure of standardized wounds in porcine skin., Materials: Porcine skin samples with standardized wounds were closed in one of five patterns with 3/0 PDS suture. Wounds were harvested and tested to failure on a materials testing machine. Load at failure, ultimate elongation, wound stiffness, and mode of failure was determined for each sample., Results: Wound closures incorporating the chain stitch knot performed as well as closures incorporating the conventional square knot for load to failure, elongation, and stiffness. Partial slippage or complete knot failure of 4/40 (10%) of the square knots used in closures was observed. 0/20 (0%) of the chain stitch knots displayed slippage. The half-blood knot performed similarly to the square and chain stitch knot in load to failure, elongation, and stiffness, however, 16/20 (80%) of these knots displayed slippage or complete knot failure., Conclusions: The chain stitch knot is as secure as the traditionally used square knot when used for termination of a continuous intradermal wound closure. This knot displays characteristics such as smaller knot volume and ease of applications that may make it a superior knot to the square knot in many clinical situations.

The isometry of the bipartite medial collateral ligament of the tarsus and two methods of stabilization by prosthetic ligament were assessed by measuring the change in distance between the origin and the insertion through full range of joint motion of the ligament and prosthetic ligaments. The single suture technique was isometric when the distal site was located at the centre of the trochlea of the talus. This site can only be used when the medial malleolus, which overlies the talus, is missing or removed. Whilst some length changes occur with hock motion, the double suture technique may be advocated in instances where the medial malleolus is present.

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-mm-diameter 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.