Clinical outcomes after common calcanean tendon rupture repair in dogs with a loop-suture tenorrhaphy technique and autogenous leukoreduced platelet-rich plasma.

OBJECTIVE: To report outcomes of dogs with common calcanean tendon (CCT) ruptures treated with a platelet-rich plasma (PRP) enhanced nonabsorbable loop-suture technique. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned dogs (n = 12). METHODS: Medical records (2015-2017) of dogs with CCT ruptures repaired with a loop-suture tenorrhaphy and autogenous leukoreduced PRP were reviewed for signalment, history, type of injury, treatment, and clinical follow-up. Outcomes were assessed by functional anatomic measurements and Canine Orthopedic Index (COI) scores transformed to percentages, with 100% representing no problems. RESULTS: Twelve tendons were treated. Two dogs had major complications that were successfully revised. Follow-up was available in 11 of 12 dogs, with a median time of 12 months (range, 4-36), including COI for 11 dogs and anatomic measurements for 6 dogs. Anatomic measurements did not differ between treated and normal contralateral limbs (midthigh muscle mass P > .99, cranial tibial muscle mass P = .37, CCT diameter P = .08, tibiotarsal joint angle P > .99). Owners scored function (COI) as 96.4% (range, 93.3%-97.8%) and quality of life as 94.6% (range, 92%-98.2%). CONCLUSION: Loop-suture tenorrhaphy with application of autogenous leukoreduced PRP at the repair site resulted in restoration of functional anatomic measurements, high COI, and client satisfaction. CLINICAL SIGNIFICANCE: Loop-suture tenorrhaphy with local application of autogenous leukoreduced PRP appears to offer an acceptable option to treat CCT injuries in dogs.

The Effect of Sliding Humeral Osteotomy (SHO) on Frontal Plane Thoracic Limb Alignment: An Ex Vivo Canine Cadaveric Study.

OBJECTIVE: To determine the effect of sliding humeral osteotomy (SHO) on frontal plane thoracic limb alignment in standing and recumbent limb positions. STUDY DESIGN: Canine cadaveric study. SAMPLE POPULATION: Canine thoracic limbs (n=15 limb pairs). METHODS: Limbs acquired from healthy Labrador Retrievers euthanatized for reasons unrelated to this study were mounted in a limb press and aligned in a standing position followed by axial loading at 30% body weight. Frontal plane radiography was performed in standing and recumbent positions pre- and post-SHO. In the standing position, lateralization of the foot was measured pre- and post-SHO using a textured grid secured to the limb press base plate. Twelve thoracic limb alignment values (mean ± SD and 95% CI) were determined using the center of rotation of angulation (CORA) method were compared using linear mixed models to determine if significant differences existed between limb alignment values pre- or post-SHO, controlling for dog, limb, and limb position. RESULTS: Six of 12 standing or recumbent alignment values were significantly different pre- and post-SHO. SHO resulted in decreased mechanical lateral distal humeral angle and movement of the mechanical humeral radio-ulnar angle, radio-ulnar metacarpal angle, thoracic humeral angle, and elbow mechanical axis deviation toward coaxial limb alignment. In the standing position, the foot underwent significant lateralization post-SHO. CONCLUSION: SHO resulted in significant alteration in frontal plane thoracic limb alignment. Additional studies are necessary to determine if the changes reported using our ex vivo model occur following SHO in vivo.

Clinical outcomes associated with the initial use of the Canine Unicompartmental Elbow (CUE) Arthroplasty System(®).

We evaluated mid- to long-term outcomes with respect to function and complications in dogs undergoing canine unicompartmental elbow (CUE) arthroplasty for treatment of medial compartment disease of the elbow. This prospective multicenter case series is the first group of clinical cases to receive CUE arthroplasty. Cases (each elbow that underwent CUE performed by a participating surgeon) were enrolled into an electronic database and prospectively followed to determine and record all associated complications, as well as functional outcomes. There were 103 cases from 18 surgeons. Final follow-up time ranged from 6 to 47 mo with a mean and median of 10 mo. Canine unicompartmental elbow was associated with 1 catastrophic (1%), 11 major (10.7%), and 28 minor (27.2%) complications. Outcomes following CUE were reported as full function in 49 cases (47.6%), acceptable function in 45 cases (43.7%), and unacceptable function in 9 cases (8.7%). We conclude that CUE arthroplasty is an appropriate consideration for treatment of medial compartment disease of the elbow in dogs.

Résultats cliniques associés à l'utilisation initiale du système d'arthroplastieCanine Unicompartmental Elbow (CUE) Arthroplasty SystemMD. Nous avons évalué les résultats à long et à moyen terme relativement à la fonction et aux complications chez les chiens subissant une arthroplastie du coude unicompartimental canin (CUC) pour le traitement de la maladie compartimentale médiale du coude. Cette série prospective de cas multicentres représente le premier groupe de cas cliniques à recevoir une arthroplastie CUC. Les cas (chaque coude qui a subi une CUC réalisée par un chirurgien participant) étaient inscrits dans une base de données électroniques et suivis de manière prospective afin de déterminer et de consigner toutes les complications connexes ainsi que les résultats fonctionnels. Il y avait 103 cas provenant de 18 chirurgiens. Le temps de suivi final s'échelonnait de 6 à 47 mois avec une moyenne et une médiane de 10 mois. Le coude compartimental canin a été associé à 1 complication catastrophique (1 %), à 11 complications majeures (10,7 %) et à 28 complications mineures (27,2 %). Les résultats après l'arthroplastie CUC ont été signalés comme une fonction complète dans 49 cas (47,6 %), une fonction acceptable dans 45 cas (43,7 %) et une fonction inacceptable dans 9 cas (8,7 %). Nous avons conclu que l'arthroplastie CUC est une considération appropriée pour le traitement de la maladie compartimentale médiale du coude chez les chiens.(Traduit par Isabelle Vallières).

Hip toggle stabilization using the TightRope® system in 17 dogs: technique and long-term outcome.

OBJECTIVE: To describe the technique for, and long-term clinical outcome of, a modified hip toggle stabilization using the TightRope® system for coxofemoral luxation repair. STUDY DESIGN: Retrospective case series. METHODS: Medical records (July 2008-July 2010) including radiographs (17 limbs) of dogs that had coxofemoral luxation repaired with the TightRope system were reviewed. Follow-up (≥12 months) was obtained by telephone interview of owners. Six dogs were available for re-evaluation, radiographs, and objective gait analysis. RESULTS: Follow-up (mean, 24 months; range, 12-43 months) by telephone interview was available for 17 dogs. Of these, 6 dogs were re-evaluated (mean, 7.5 months; median 12.5 months: range, 4-24 months) and had gait analysis. Mean duration of luxation before surgical intervention was 7.5 days (median, 7 days; range, 2-44 days). There was a single case of relaxation 27 months postoperatively. One dog died from non-surgical related circumstances. Objective gait analysis showed equal pelvic limb use in all 6 dogs available for re-evaluation. All owners of living dogs reported limb function as being good to excellent, and perceived that their dogs were pain free. Radiographs (mean, 7.5 months; median, 12.5 months; range, 4-24 months post surgery) of 6 dogs showed no progression of osteoarthritis in comparison to immediate postoperative radiographs. CONCLUSIONS: Hip toggle with the TightRope system as a prosthetic ligament of the head of the femur produces a favorable clinical outcome with high owner acceptance.

Theory and development of a unicompartmental resurfacing system for treatment of medial compartment disease of the canine elbow.

Medial compartment disease (MCompD) of the canine elbow can be defined as clinical signs attributable to articular cartilage loss of the medial coronoid process (MCP) of the ulna and medial aspect of the humeral condyle without significant lateral compartment pathology. Whereas outcomes associated with treatment of defined cohorts of dogs with MCompD have not been published, the impressions of many surgeons are that non-surgical management or surgical treatment of the MCP alone does not result in long term highly functional outcomes. Thus, alternative surgical options for treatment of MCompD have been developed including various osteotomies and total elbow replacement (TER) with "successful" outcomes reported in case series. Results and data on safety have been reported for relatively few of these procedures and when reported, major complication rates have been >10% and catastrophic complications have been reported. Accordingly, we sought to develop a surgical technique with the objective of obtaining higher levels of safety and efficacy in the treatment of dogs with MCompD. This report describes the rationale for, and development of, a unicompartmental resurfacing system for treatment of MCompD in the canine elbow.

The effect of Cox-2 specific inhibition on direct fracture healing in the rabbit tibia.

OBJECTIVE: The purpose of this study was to evaluate the effect of Cox-2 administration on direct (primary) fracture healing. METHODS: A transverse tibial osteotomy was created in adult male rabbits and rigidly fixed in compression using a 2.7-mm dynamic compression plate. Animals were randomized to receive either rofecoxib (12.5 mg orally per day) or placebo. Animals were killed at 4 weeks and fracture healing assessed by mechanical testing. RESULTS: There were no significant differences between the control and Cox-2 treated animals in terms of mechanical strength at 4 weeks. There was a high complication rate of peri-implant fractures during the daily medication administration. CONCLUSION: The immediate administration of a Cox-2 specific inhibitor did not impair primary (direct) bone healing at the dose administered in this rabbit tibial osteotomy model.

Effect of positioning, scan plane, and arthrography on visibility of periarticular canine shoulder soft tissue structures on magnetic resonance images.

This study was performed to determine the effect of shoulder extension and flexion, imaging plane, and intraarticular paramagnetic contrast medium administration on the visibility of soft tissue structures surrounding the canine shoulder joint using magnetic resonance (MR) imaging. Eight dogs without shoulder disease were imaged using a 1.5 T MR scanner. In all dogs, T1- and T2-weighted spin-echo sequences in sagittal, transverse, and dorsal planes, and a sagittal short tau inversion recovery (STIR) sequence were acquired with the shoulder joint in extension. In five dogs, postintravenous contrast medium T1-weighted images were obtained and in five dogs, MR arthrography was performed in flexion and extension. Each specific soft tissue structure was assigned a visual assessment score of 0-3 and descriptive statistics were calculated. The biceps brachii, supraspinatus, and teres minor muscles and tendons, and the biceps tendon sheath were best seen in the sagittal and transverse planes. The infraspinatus was well-visualized in all planes, the subscapularis was best seen in the transverse and dorsal planes, and the capsuloligmentous complexes were best seen in the transverse and dorsal planes. Limb extension improved conspicuousness of the medial capsuloligamentous stuctures. Arthrography resulted in greater conspicuousness of the biceps brachii tendon, biceps tendon sheath, infraspinatus, supraspinatus, subscapularis, medial joint capsule, medial glenohumeral ligament, and the lateral joint capsule-glenohumeral ligament complex. The major periarticular anatomic structures of the normal canine shoulder were consistently identified using the protocols described in this investigation, but arthrography with the joint in extension resulted in the best visualization of all structures.

Measurement of humeroradial and humeroulnar transarticular joint forces in the canine elbow joint after humeral wedge and humeral slide osteotomies.

OBJECTIVE: To determine the effect of humeral wedge and humeral slide osteotomies on force distribution between the articular surfaces of the humerus and the radius and ulna in normal canine thoracic limbs. STUDY DESIGN: In vitro mechanical testing. SAMPLE POPULATION: Cadaveric canine right thoracic limbs (n=12). METHODS: Transarticular elbow force maps were measured using a tactile array pressure sensor in elbow joints of axially aligned limbs under 200 N axial load before and after humeral wedge and humeral slide osteotomies. RESULTS: Loading induced 2 distinct areas of high forces that corresponded with the proximal articular surfaces of the radius and ulna. Mean force on the proximal articular surface of the ulna was reduced by 25% and 28% after 4 and 8 mm sliding osteotomies, respectively. Statistically significant differences were not observed for the wedge osteotomies. CONCLUSION: Humeral slide osteotomy significantly decreases force on the proximal articular surface of the ulna. CLINICAL RELEVANCE: The proximal articular surface of the ulna contributes significantly to load transfer through the canine elbow joint. Abnormalities that significantly increase this force might contribute to canine elbow dysplasia, specifically fragmentation of the medial coronoid process and osteochondritis dissecans of the medial aspect of the humeral condyle. Under the conditions studied, the overall reduction in mean joint surface force across the proximal articular surface of the ulna after humeral slide osteotomy indicates that this technique merits further investigation for potential use in medial compartmental osteoarthritis of the canine elbow joint.

Mechanical comparison of 3.5 mm broad dynamic compression plate, broad limited-contact dynamic compression plate, and narrow locking compression plate systems using interfragmentary gap models.

OBJECTIVES: To compare (1) pullout properties between 3.5 mm cortical and locking screws, and (2) mechanical properties and gap displacements between the 3.5 mm broad limited-contact dynamic compression plate (LC-DCP), broad dynamic compression plate (DCP), and narrow locking compression plate (LCP), during axial loading of plate-stabilized diaphyseal fragments with an interfragmentary gap. STUDY DESIGN: In vitro mechanical testing of implanted polyurethane foam (PUF) hollow cylinders that simulated compact or osteopenic diaphyseal bone. SAMPLE POPULATION: (1) Five cortical and locking screws and (2) 4 PUF-plate constructs for each plate type; using high- and low-density (0.8 and 0.32 g/cm(3)) cylinders. METHODS: (1) Screws were completely extracted at 5 mm/min. (2) Plated constructs were axially compressed at 300 N/s for 10 cycles from 5 to 355 N to determine gap displacement during physiologic loading, followed by single cycle increasing load to failure. RESULTS: Pullout properties were not different between screw types. All plate constructs had yield loads over 3 times trotting loads. Gap closure occurred with LC-DCP and DCP constructs, but not LCP constructs. LCP construct properties were most similar to LC-DCP and DCP construct properties in the low-density model. CONCLUSION: All plate systems sustained physiologic limb loads. Only LCP constructs maintained some gap integrity, although LC-DCP and DCP screws were placed in neutral position. CLINICAL RELEVANCE: The LCP system is more likely than LC-DCP and DCP systems, with neutrally positioned screws, to maintain a planned interfragmentary gap, although gap strains range from 0% to 15% across the 2 mm gap during a trot load.

Proinflammatory cytokine activities, matrix metalloproteinase-3 activity, and sulfated glycosaminoglycan content in synovial fluid of dogs with naturally acquired cranial cruciate ligament rupture.

OBJECTIVE: To measure and compare activities of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and matrix metalloproteinase-3 (MMP-3); as well as sulfated glycosaminoglycan (S-GAG) content in synovial fluid from dogs with cranial cruciate ligament rupture (CCLR) and dogs with clinically normal stifles. To determine whether correlations exist between demographic and disease-related variables and these synovial markers. STUDY DESIGN: Prospective clinical study. ANIMALS: Dogs with CCLR (n=23) and Beagles with normal stifle joints (n=21). METHODS: Synovial fluid activities of proinflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) were determined by bioassay. MMP-3 activity was measured using fluorogenic substrate. S-GAG contents were determined by dimethylmethylene blue dye-binding assay. Mann-Whitney U-test was used to compare results from CCLR joints with normal controls. Spearman's rank correlation test was used to evaluate associations between demographic and disease-related markers and synovial markers. RESULTS: Mean values for synovial markers were significantly higher in CCLR joints compared with controls. IL-1beta and MMP-3 were positively correlated with lameness duration. CONCLUSIONS: Activities of proinflammatory cytokines, MMP-3 activity and S-GAG contents were significantly elevated in synovial fluid from canine stifle joints with naturally acquired CCLR. These results indicate that there is joint inflammation and increased release of GAGs into synovial fluid, suggesting that these inflammatory changes are associated with depletion of proteoglycan from articular cartilage. CLINICAL RELEVANCE: Medical and surgical treatments designed to decrease joint inflammation and breakdown of proteoglycans may be of value in the management of CCLR in the dog.

Computed tomographic evaluation of canine radioulnar incongruence in vivo.

OBJECTIVE: To compare radioulnar incongruence (RUI) of normal canine elbows and elbows with arthroscopically confirmed medial compartment disease in vivo using systematic computed tomography (CT) measurements. STUDY DESIGN: Prospective comparison of RUI measurements in normal and dysplastic canine elbows. SAMPLE POPULATION: Right elbows of 25 medium-large breed, adult dogs with medial compartment disease and 9 medium-large breed, adult dogs with no elbow disease. METHODS: Transverse CT images of proximal radioulnar articulation were reformatted to dorsal and sagittal planes. RUI in 3 locations of the forelimb's medial coronoid was measured. Arthroscopy confirmed diagnosis of medial compartment disease in the diseased group. RUI measurements of the diseased and normal elbows were compared. RESULTS: Cumulative statistical analysis of RUI in all planes revealed no significant difference between the normal and abnormal elbows (P = .61). The abnormal elbows had negative mean RUI at the mid (P = .56) and cranial (P = .24) coronoid regions that were not significantly different from normal elbows and mean positive RUI at the base coronoid that was significantly greater than in normal elbows (P = .00082). CONCLUSION: Canine elbows with established medial compartment disease do not have significant RUI at the medial coronoid region at the time of diagnosis when compared with normal elbows. CLINICAL RELEVANCE: If RUI is a significant factor in the pathophysiology of medial compartment elbow disease in the dog, it does not appear to be present at the time of diagnosis of disease. Ulnar or radial osteotomies do not appear to be indicated for restoration of normal radioulnar articular surface alignment.

Direct and indirect markers of cartilage metabolism in synovial fluid obtained from dogs with hip dysplasia and correlation with clinical and radiographic variables.

OBJECTIVE: To compare activities of interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, and matrix metalloproteinase (MMP)-3 and contents of sulfated glycosaminoglycan (S-GAG) in joint fluid obtained from dogs with hip dysplasia (HD) and clinically normal dogs, evaluate correlations among these markers in joint fluid obtained from dogs with HD, and evaluate correlations between each marker and clinical and radiographic variables. Animals-26 dogs with HD (clinical group) and 43 clinically normal Beagles (control group). PROCEDURE: Joint fluid was aseptically collected from the hip joints of all dogs. For each dog in the clinical group, age, duration of lameness, radiographic osteoarthritis (OA) score, and Norberg angle in each affected joint were recorded. Activities of IL-1beta, IL-6, TNF-alpha, and MMP-3 and S-GAG contents were measured. Values were compared between groups by use of Mann-Whitney U tests, and the Spearman rank correlation test was used to evaluate correlations among markers and between each marker and clinical or radiographic variables. RESULTS: Values of all markers were significantly higher for the clinical group, compared with values for the control group. There was a moderate positive correlation between lameness duration and IL-6 activity and a strong negative correlation between the Norberg angle and IL-1beta activity. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of our results indicated that there was a significant increase in markers of OA in dogs with HD. Activities of IL-1beta and IL-6 in joint fluid of dogs with HD may be influenced by the severity of laxity in the hip joint and lameness duration, respectively.

Comparison of arthroscopic and radiographic abnormalities in the hip joints of juvenile dogs with hip dysplasia.

OBJECTIVE: To compare radiographic and arthroscopic abnormalities in juvenile dogs with clinically apparent hip dysplasia. DESIGN: Case series. ANIMALS: 52 dogs (70 hip joints) with clinical signs of hip dysplasia scheduled to undergo triple pelvic osteotomy. PROCEDURE: A ventrodorsal radiographic projection of the pelvis was evaluated by a radiologist unaware of clinical and arthroscopic findings, and radiographic osteoarthritic abnormalities were judged and scored as absent (0), mild (1), moderate (2), or severe (3). Arthroscopy was performed by a surgeon unaware of clinical and radiographic findings, and arthroscopic abnormalities were graded from 0 (normal) to 5 (exposed, eburnated subchondral bone). RESULTS: In 30 of the 70 (43%) hip joints, no radiographic osteoarthritic abnormalities were seen. Severe, full-thickness articular cartilage lesions (grade 4) of the femoral head or acetabulum were seen arthroscopically in 14 (20%) joints. Lesions > or = grade 2 were seen in 60 (86%) joints. Partial tearing of the ligament of the femoral head was present in 57 (81%) joints, and complete rupture was seen in 5 (7%). Radiographic abnormalities were seen in 13 of the 14 (93%; 95% confidence interval, 66% to 99.8%) joints with grade 4 arthroscopic abnormalities but in only 23 of the 46 (50%; 95% confidence interval, 35% to 65%) joints with grade 2 or 3 arthroscopic abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that radiography is not a sensitive method for identifying moderate cartilage lesions in juvenile dogs with hip dysplasia. If moderate cartilage lesions are an important prognostic indicator for the success of triple pelvic osteotomy, then methods other than radiography should be used to detect these lesions.

Effect of a ventral slot procedure and of smooth or positive-profile threaded pins with polymethylmethacrylate fixation on intervertebral biomechanics at treated and adjacent canine cervical vertebral motion units.

OBJECTIVE: To investigate the biomechanics of cervical vertebral motion units (VMUs) before and after a ventral slot procedure and after subsequent pin-poly-methylmethacrylate (pin-PMMA) fixation and to assess the use of smooth and positive-profile threaded (PPT) pins in pin-PMMA fixation and intravertebral pin placement. SAMPLE POPULATION: Cervical portions (C3 through C6 vertebrae) of 14 cadaveric canine vertebral columns. PROCEDURE: Flexion and extension bending moments were applied to specimens before and after creation of a ventral slot across the C4-C5 intervertebral space and after subsequent smooth or PPT pin-PMMA fixation at that site. Data for the C3-C4, C4-C5, and C5-C6 VMUs were compared among treatments and between pin types, and pin protrusion was compared between pin types. RESULTS: Compared with values in intact specimens, ventral slot treatment increased neutral zone range of motion (NZ-ROM) by 98% at the treated VMUs and appeared to decrease overall ROM at adjacent VMUs; pin-PMMA fixation decreased NZ-ROM by 92% at the treated VMUs and increased overall NZ-ROM by 19% to 24% at adjacentVMUs. Specimens fixed with PPT pins were 82% (flexion) and 80% (extension) stiffer than smooth-pin-fixed specimens. Overall, 41% of pins protruded into foramina; PPT pins were more likely to protrude into transverse foramina. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that fixation of a cervical VMU alters the biomechanics of adjacent VMUs and may contribute to intervertebral degeneration of adjacent intervertebral disks. Use of threaded pins may lower the incidence of pin loosening and implant failure but enhances the likelihood of transverse foramina penetration.

Accuracy of computerized tomographic evaluation of canine radio-ulnar incongruence in vitro.

OBJECTIVE: To evaluate the accuracy of linear measurements obtained from computer tomography (CT) images of staged radio-ulnar incongruence in a canine cadaver forelimb model. STUDY DESIGN: CT evaluation of induced progressive radio-ulnar incongruence in canine cadaveric forelimbs. SAMPLE POPULATION: Eight cadaveric canine left forelimbs. PROCEDURE: A type 2 external skeletal fixator (ESF) with linear motors was attached to the radius in 8 cadaveric left canine forelimbs. Contiguous incremental and helical CT images of the proximal radio-ulnar articulation were acquired in the transverse, sagittal and dorsal planes. The radius was shortened by 1, 2, and 4 mm increments and scanning protocols were repeated at each increment. Digital caliper and CT image analysis measured the progressive change in distance between 2 marking spheres and the epiphyseal bone surfaces of the radio-ulnar articulation. Statistical analysis of measurements from incremental and helical CT acquisitions, and direct and reformatted images were compared with inter-sphere distance using Pearson product moment correlation coefficients. RESULTS: The reformatted incremental acquisition series at the mid-coronoid in the oblique plane had the highest correlation coefficient (r-value) at 0.908. The mid-coronoid in the dorsal plane had the second highest r-value (0.856). The coronoid incisure in the sagittal plane had an r-value of 0.826. The reformatted incremental acquisition series at the coronoid incisure in the oblique plane had the lowest r-value, 0.592. CONCLUSION: Measurement of radioulnar incongruence may be best performed using reformatted incremental acquisition CT in the mid-coronoid region in an oblique plane. CLINICAL RELEVANCE: Use of the technique reported in this study may enable determination of the association, if any, between radioulnar incongruence and developmental diseases of the canine elbow.

In vitro force mapping of normal canine humeroradial and humeroulnar joints.

OBJECTIVE: To determine the distribution of force between the articular surfaces of the humerus and radius and between the humerus and ulna in normal canine forelimbs. SAMPLE POPULATION: 12 cadaveric canine right forelimbs. PROCEDURE: Transarticular force maps were created by placing a tactile array pressure sensor into the elbow joint cavity and loading cadaveric forelimbs in a materials testing system. Mean joint forces were determined at loads of 50, 100, 150, and 200 N. RESULTS: All tests produced 2 distinct areas of high load that corresponded with the proximal articular surfaces of the radius and ulna. Mean forces for the radial proximal articular surface were slightly but significantly greater than for the ulna, averaging 51% to 52% of total force for all applied loads. CONCLUSIONS AND CLINICAL RELEVANCE: The proximal articular surface of the ulna contributes substantially to load transfer through the canine elbow joint. Abnormalities, which increase this load, might contribute to canine elbow joint dysplasia, specifically fragmentation of the medial coronoid process and osteochondritis dissecans of the medial aspect of the humeral condyle. In the treatment of these conditions, the normal force distribution within the canine elbow joint should be taken into consideration.

The effect of stem length on femoral component positioning in canine total hip arthroplasty.

OBJECTIVE: To determine the effects of femoral prosthesis stem length on positioning of the femoral component within the canine femur. STUDY DESIGN: An in vitro experimental study. SAMPLE POPULATION: Eleven adult, mixed breed, canine cadaver femurs. METHODS: Polymethylmethacrylate centralized Biomedtrix size 5, 6, and 7 standard and 1cm shortened implants were placed in specimens, manipulated to achieve maximal displacements of the implant tip in each plane, and radiographed. Measurements of the implant angle, tip offset, and minimal tip to endosteal surface distance were obtained with image processing software. The effects of implant length and size on implant positioning were evaluated with the use of Student's t, chi(2) exact, and 2-way ANOVA testing. RESULTS: Statistically significant increases were noted in tip to caudal cortex distance in the sagittal plane, and available angle variability and tip offset variability in the transverse plane for shortened size 6 and 7 stems relative to the standard stems. No significant differences were noted in size 5 stems. Statistically significant increases in tip to caudal cortex distance and transverse plane available angle variability for standard 6 compared to standard 7 stems were noted. CONCLUSIONS: Shortened stems result in statistical improvement of several variables of femoral component positioning. However, the improvement appears to be clinically negligible. CLINICAL RELEVANCE: Alteration of current stem lengths is not recommended. The use of undersized standard implants may improve femoral component positioning in total hip arthroplasty.

Unusual urethral calculi in two male dogs.

The clinical presentation and advanced size of the two calculi described in this report are both atypical and noteworthy. Both dogs were presented initially with signs of hematuria, stranguria, and perineal discomfort. Each calculus was visible on survey abdominal radiographs and was present in the region of the ischial arch. Both dogs underwent a perineal urethrotomy to retrieve the calculus. Resolution of clinical signs was obtained in one case, which was referred within 2 months of the onset of clinical signs. The second dog was medically managed for approximately 2.5 years before referral. Surgical intervention failed to restore urinary continence in this second dog. Early detection of similar cases may be important in optimizing clinical outcome following appropriate treatment.