Veterinary and Comparative Orthopaedics and Traumatology (VCOT) Veterinary and Comparative Orthopaedics and Traumatology (VCOT) vcot de-de Sat, 10 Oct 15 10:57:55 +0200 Ahead of print: Effect of bending direction on the mechanical behaviour of 3.5 mm String-of-Pearls... Objective: To compare the bending properties of String-of-Pearls® (SOP) and Limited Contact Dynamic Compression Plate® (LC-DCP) constructs in orthogonal bending directions. Methods: 3.5 mm SOP and LC-DCP plates were fixed to a bone model simulating a comminuted tibial fracture. Specimens were non-destructively tested in both mediolateral and craniocaudal bending for 10 cycles. Bending stiffness and total angular deformation were compared using parametric analyses (p <0.05). Results: For both constructs, stiffness was significantly less when bending moments were applied against the thickness of the plates (mediolateral bending) than against the width (craniocaudal bending). When compared to the mediolateral plane, bending constructs in the craniocaudal plane resulted in a 49% (SOP group) and 370% (LC-DCP group) increase in stiffness (p <0.001). Mediolateral bending stiffness was significantly greater in the SOP than the LC-DCP constructs. Conversely, in craniocaudal bending, SOP constructs stiffness was significantly less than that of the LC-DCP constructs. The differences between the two constructs in total angular deformation had an identical pattern of significance. Clinical significance: This study found that SOP showed less variability between the orthogonal bending directions than LC-DCP in a comminuted fracture model, and also described the bi-planar bending behaviour of both constructs. Although not exhibiting identical bending properties in both planes, SOP constructs had a more homogenous bending behaviour in orthogonal loading directions. The difference between the SOP with a circular cross sectional shape compared to the rectangular shape of standard plates is probably responsible for this difference.... J. Benamou (1), R. M. Demianiuk (1), S. Rutherford (2), C. Beckett (3), M. G. Ness (2), R. C. Haut (3), L. M. Déjardin (1) 25076 2015-10-09 08:40:27 Ahead of print: High energy focused shock wave therapy accelerates bone healing Objectives: To evaluate the influence of shock wave therapy (SWT) on radiographic evidence of bone healing after tibial plateau leveling osteotomy (TPLO). Methods: Healthy dogs between two to nine years of age that underwent TPLO were randomly assigned to receive either electro-hydraulic SWT (1,000 shocks) or sham treatment (SHAM). Treatment or SHAM was administered to the osteotomy site immediately postoperatively and two weeks postoperatively. Three blinded radiologists evaluated orthogonal radiographs performed eight weeks postoperatively with both a 5-point and a 10-point bone healing scale. Linear regression analysis was used to compare median healing scores between groups. Results: Forty-two dogs (50 stifles) were included in the statistical analysis. No major complications were observed and all osteotomies healed uneventfully. The median healing scores were significantly higher at eight weeks postoperatively for the SWT group compared to the SHAM group for the 10-point (p <0.0002) and 5-point scoring systems (p <0.0001). Clinical significance: Shock wave therapyapplied immediately and two weeks postoperatively led to more advanced bone healing at the eight week time point in this study population. The results of this study support the use of electro-hydraulic SWT as a means of accelerating acute bone healing of canine osteotomies. Additional studies are needed to evaluate its use for acceleration of bone healing following fracture, or with delayed union.... N. R. Kieves (1), C. S. MacKay (2), K. Adducci (1), S. Rao (1), C. Goh (1), R. H. Palmer (1), F. M. Duerr 25075 2015-10-09 08:39:35 Ahead of print: Tensions generated in a lateral fabellotibial suture model Objectives: To compare suture tension on a simulated lateral fabellotibial suture model using various methods of application of tension, fixation, and suture materials. Methods: Veterinarians constructed simulated lateral fabellotibial suture constructs on a tying stand with force sensor. Participants used combinations of 45 kg test monofilament nylon, metric 7 braided polyethylene, crimps, crimper, or knots, with their choice of instruments to secure the constructs. The tension in completed constructs was measured and comparisons were made between nylon and polyethylene, the use of crimps compared to knots, and the use of a mechanical distractor compared to hand tightening techniques. A value of p <0.05 was considered significant. Results: Fifty-eight veterinarians created 72 lateral suture constructs. Final tensions generated ranged from 1.4–171.0N. The median tension of nylon sutures (43.9N ± 44.7N) was significantly greater than polyethylene sutures (9.5 N ± 19.6N). The median tension of constructs secured with crimps (62.8N ± 42.4N) was significantly greater than constructs secured with knots (11.8 N ± 14.8N). The mechanical distractor generated significantly higher median tension (78N ± 50.4N), compared to methods without the device (18.6 N ± 25.1N). Clinical significance: There was a large variability in the tension generated in simulated lateral fabellotibial constructs. Veterinarians who used nylon, crimps, and the mechanical tensioner generated constructs with greater tensions.... A. F. Burton (1), C. Horstman (2), D. R. Mason (2) 25074 2015-10-09 08:27:09 Ahead of print: Variability associated with assessing changes in position of a canine uncemented... 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.... H. M. Korani (1), D. J. Marcellin-Little (1), S. C. Roe (1) 25073 2015-10-09 08:26:16 Ahead of print: Influence of a titanium mesh on the management of segmental long bone defects Objectives: To evaluate the influence of titanium mesh on guided bone regeneration when used, either alone or in combination with autogenous bone block graft, in a canine ulnar model. Methods: Thirty-two, purpose bred, adult, castrated male Beagles were used, divided into four equal-size groups. A unilateral mid-diaphyseal ulnar critical-size defect was created in each dog. The ulnar segments were stabilized with a stainless-steel plate and screws. Each defect was managed by: no further treatment (Group A) or by placement of a bone block graft taken from the ipsilateral iliac crest (Group B), or titanium mesh wrapped around the ulna (Group C), or a bone block graft and titanium mesh (Group D). After six months, bone block biopsies were performed and the samples were scanned using micro-computed tomography. Qualitative histological evaluation was performed on two non-decalcified longitudinal sections from each block. Results: No significant differences in terms of mineralized bone volume were detected between the grafted sites (Groups B and D) or between the non-grafted ones (Groups A and C). The histological evaluation indicated good integration of the bone blocks irrespective of the use of titanium mesh. Clinical significance:The use of titanium mesh does not influence the amount of bone formation. The canine ulnar critical-size defect model seems to be a reliable model to use in experimental studies.... S. I. Zoi (1, 2), S. A. Papadimitriou (3), A. D. Galatos (2), N. N. Prassinos (3), D. Psalla (3), M. Dalstra (4), A. Stavropoulos (5) 25072 2015-10-09 08:25:02 Ahead of print: Effect of doxycycline on contralateral canine cranial cruciate ligament rupture Objective: To evaluate whether doxycycline administered to dogs with unilateral cranial cruciate ligament rupture (Uni-CCLR) would decrease the risk of contralateral-CCLR (Co-CCLR). To evaluate predictors for Co-CCLR survival. To evaluate if a predisposition of Labrador Retrievers to Co-CCLR exists when compared to other breeds. Methods: In this prospective randomized controlled clinical trial, 69 client-owned dogs with Uni-CCLR were randomly assigned to doxycycline (group-D: 7.5 mg/kg PO BID x 6 weeks) or non-doxycycline (group-ND: negative control). Medical and imaging data, time from Uni- to Co-CCLR and to follow-up were recorded. Statistics included chi-squared test, logistic regression, Kaplan-Meier survival analysis, log rank test, survival curves, and frailty model (p D. J. F. von Pfeil (1, 2), J. Sung (3), J. Barry (4), K. Hayashi (3), M. R. Edwards (5) 25032 2015-10-01 11:43:52 Ahead of print: Locking compression plate for treatment of 20 distal fractures of the radius and... Objective: To evaluate retrospectively the effectiveness of the Locking Compression Plate® (LCP), in the form of either a straight or notched head T-plate, for the treatment of fractures of the distal radius and ulna in a series of 20 toy and miniature breed dogs. Methods: The medical records of toy and miniature breed dogs (<6 kg), greater than six months of age, with fractures of the distal radius and ulna from two veterinary hospitals were reviewed. The inclusion criteria included: fractures of the distal 1/3 of the radius and ulna and repair with open reduction and internal fixation utilizing an LCP plate (straight or notched head T-plate). Results: Twenty fractures (20 dogs) satisfied the inclusion criteria; eight straight and 12 notched head T-plates were used, either 2.0 mm (n = 13) or 2.4 mm (n = 7). Hybrid fixation was performed in all dogs in one or both fragments. Mean time to radiographic union was 6.9 ± 2.5 weeks (range: 4–12 weeks) in 18/20 dogs with radiographic follow-up. One complication was observed: infection that resolved with antibiotic medication and plate removal. No other major complications occurred by the time of last follow-up. In all cases (mean follow-up: 15 ± 7 months), the reported limb function as evaluated by the referring veterinarian or owner was excellent. Clinical significance: The LCP, used as a hybrid construct for the treatment of distal radial and ulnar fractures was shown to yield excellent clinical results with both uncomplicated healing and excellent functional outcomes in this series of toy and miniature breed dogs.... S. Gibert (1), G. R. Ragetly (1), R. J. Boudrieau (2) 25031 2015-10-01 11:42:33 Ahead of print: Planned wedge size compared to achieved advancement in dogs undergoing the modified... 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.... M. W. Kapler (1), D. J. Marcellin-Little (1), S. C. Roe (1) 25030 2015-10-01 11:41:25 Ahead of print: Comments on Torsional Testing G. Smith (1) 25029 2015-10-01 11:37:55 Ahead of print: False ankylosis of the temporomandibular joint in a cat Objective: To describe the use of two-dimensional computer-assisted tomography (CT) with three-dimensional (3D) reconstruction in the diagnosis and planning of surgical treatment of a case of false ankylosis of the temporomandibular joint. Case report: A young European Shorthaired cat was presented with the complaint of inability to eat and open its jaws. A CT scan with 3D reconstruction allowed visualization of the lesion which was causing extra-articular ankylosis of the temporomandibular joint. Surgery was performed to resect an osseous lesion of the zygomatic arch, thus freeing the temporomandibular joint. Postoperative physical therapy was initiated immediately following surgery, and then carried out by the owner with a one year follow-up. Clinical examination of the cat was performed during regular office visits (at 1 month and 3 months following surgery), which allowed objective assessment of postoperative recuperation. At the end of a year, the owners reported that the cat had maintained sufficient jaw opening without any signs consistent with chronic pain. Conclusion: Computed tomography scan with 3D reconstruction allowed planning of the surgical correction of extra-articular ankylosis of the temporomandibular joint, and in this case condylectomy was avoided, since temporomandibular joint range-of-motion was maintained.... l. Larguier (1), N. Jamet (1) 24917 2015-09-18 13:51:23 Ahead of print: Comparison of the tibia plateau angle between small and large dogs with cranial... Objectives: To compare the conformation of the proximal tibia evaluated on a medio-lateral radiograph between small and large dogs with cranial cruciate ligament disease (CCLD). Methods: Retrospective clinical study with dogs having radiographic evaluation and CCLD confirmed at surgery. The first group (n = 52) was comprised of dogs weighing less than 15 kg and the second group (n = 52) of dogs weighing more than 15 kg. The tibial plateau angle (TPA), the relative tibial tuberosity width (rTTW), and the Z angle were measured on preoperative radiographs with imaging measurement software. Linear mixed models were used to assess the effect of weight, age, sex, and neutered status on radiographic measurements and to estimate interobserver variabilities. Results: The small dog group had a greater TPA (30.1° ± 5.3; p <0.001 with a mean difference of 4.9° [95% CI: 3.8–6.0]) and Z angle (69.9° ± 5.6; p<0.001 with a mean difference of 6.1° ([95% CI: 4.9–7.4]) than the large dog group. Sex and neutered status further influenced the TPA and Z angle values. No significant effect was observed on the rTTW values. A strong correlation was found between the TPA and the Z angle (r = 0.61, p <0.001). Variances were not significantly different between observers. Overall the interobserver variability was low suggesting that agreement was good. Clinical significance: Small dogs with CCLD have a steeper tibial plateau than large dogs with CCLD. Sex and neutered status also had an effect on some measured variables. This anatomical difference could influence the surgical technique, which may affect the outcome. The good interobserver agreement suggests the observer is unlikely to influence surgical planning.... A. Aertsens (1), J. Rincon Alvarez (1), C. M. Poncet (1), H. Beaufrère (1), G. R. Ragetly (1) 24916 2015-09-18 13:50:36 Ahead of print: Treatment of cranial cruciate ligament rupture in the feline stifle Objective: To determine whether a lateral suture placed with bone anchors between quasi-isometric points in a cat is superior to a standard fabella-tibial suture, for the stabilization of cranial cruciate ligament (CrCL) rupture compared to an intact stifle joint. Study design: Biomechanical cadaveric study. Methods: Six stifle joints with intact cruciate ligaments from three skeletally mature cats were placed in a loading mounting set and tested with axial loads of 20N and 60N at three different joint angles (75°,130° and 160°). The procedure was repeated with a transected CrCL; a stabilized stifle joint after a combination of three lateral suture techniques (fabella-tibial suture technique [SFT]; femoro-tibial suture technique 1 [FTS-1] and femoro-tibial suture technique 2 [FTS-2]). Radiographic examination of the relative position of the tibia to the fixed femur was compared. Results: Stabilization of the stifle joint with lateral sutures had comparable stability to the intact specimens in the cranio-caudal direction (p = 0.2) but not in the proximo-distal direction for the SFT (p = 0.04) and FTS-2 technique (p = 0.03). There was no significant difference between the three stabilization techniques (p >0.05). Clinical significance: Lateral sutures placed with bone anchors at quasi-isometric points performed better than SFT and FTS-2 in stabilizing the feline stifle after CrCL rupture in the proximo-distal plane. Biomechanical stability in the cranio-caudal plane after placement of a lateral suture across the feline stifle was similar to the intact CrCL.... R. De Sousa (1), M. Sutcliffe (2), N. Rousset (3), M. Holmes (3), S. J. Langley-Hobbs (4) 24915 2015-09-18 13:14:45 Ahead of print: Thoracic bite trauma in dogs and cats: a retrospective study of 65 cases Objectives: To report a case series of thoracic bite trauma in dogs and cats and to evaluate risk factors for mortality. Methods: A retrospective study concerning thoracic bite wounds in dogs and cats was performed. Lesions were categorized by depth of penetration: no wound, superficial, deep or penetrating. Thoracic radiographic reports were reviewed. Lesion management was classified as non-surgical, wound exploration, or explorative thoracotomy. Results: Sixty-five cases were collected. Twenty-two percent of patients with normal respiratory patterns showed thoracic radiographic lesions. Respiratory distress was not correlated with mortality. Twenty-eight patients were presented with superficial wounds and 13 with deep wounds. Eight patients exhibited penetrating wounds. Radiographic lesions were observed in 77% of dogs and 100% of cats. Explorative thoracotomy was performed in 28% of patients, and surgical wound exploration in 17.2%. With the exception of skin wounds, thoracic wall discontinuity was the most frequent lesion. Thoracotomy was associated with increased length of hospitalisation but was not correlated with mortality. The mortality rate was 15.4%. No studied factor correlated with mortality, and the long-term outcomes were excellent. Clinical significance: A penetrating injury, more than three radiographic lesions, or both together seemed to be indicative of the need for a thoracotomy. In the absence of these criteria, systematic bite wound explorative surgery is recommended, with extension to thoracotomy if thoracic body wall disruption is observed.... Q. Cabon (1), C. Deroy (1), F. X. Ferrand (1), P. Pillard (1), T. Cachon (1), D. Fau (1), I. Goy-Thollot (2), E. Viguier (1), C. Carozzo (1) 24914 2015-09-18 11:41:53 Femoral head and neck excision K. A. Johnson (1) 24896 2015-09-14 10:12:47 Surgical correction of a bilateral congenital tarsal hyperextension deformity in a cat Case description: An approximately three-month-old, 0.45 kg female Domestic Shorthaired kitten with stiff hyperextended hindlimbs distal to the talo-central joint is reported. Attempts at repositioning of the joints by flexion failed while increased manipulative forces caused signs of pain and vocalization. Orthogonal radiographic views revealed a significant malarticulation of the tarsus. Goniometric measurments revealed a 145° extensor and 95° internal torsional deformity. Treatment and outcome: Pantarsal arthrodesis with a transarticular external fixation system was performed for both limbs in two separate stages. Pre-assembled frames were composed of two 40 mm diameter half rings (on the medial side) and two 40 mm diameter full rings connected with two pre-contoured (125° flexion) rods from proximal to distal. Following transection of the superficial and deep digital flexor tendons, cartilage was removed from the articular surfaces, autologous cancellous bone graft was inserted, and joints were fixed in 125° flexion with pre-contured external frames. The cat commenced weight-bearing bilaterally immediately postoperatively. Frames were removed 32 and 27 days after application. Two months after frame removal, joint fusion was confirmed and full weight-bearing at the walk and run was achieved. Clinical relevance: To our knowledge, this is the first report of surgical correction of a bilateral congenital tarsal hyperextension deformity by pantarsal arthrodesis using a transarticular external fixation system.... C. Yardımcı (1), A. Ozak (1), H. Özlem Nisbet (1) 24781 2015-08-24 13:54:00 Unicameral bone cyst of the patella in a young dog This report describes a case of a solitary unicameral patellar bone cyst in a young dog. A five-month-old, male Dobermann Pinscher dog was referred for a 10-day left hindlimb lameness. A mild swelling of the peripatellar soft tissues of the left patella was detected upon physical examination. Signs of pain were elicited upon direct palpation of the patella. Radiographic examination revealed an oval radiolucency within the medullary cavity at the base of the left patella. Radiographic examination, arthroscopy, and histopathology findings supported the diagnosis of a benign patellar bone cyst. The condition was treated by surgical curettage and autogenous bone graft harvested from the ipsilateral proximal tibia. Clinical signs, including lameness and signs of pain upon deep palpation, disappeared three weeks after surgery. Follow-up re-evaluation five years after surgery revealed no recurrence of the cyst and the patient was asymptomatic. M. Petazzoni (1), F. Briotti (2), B. Beale (3) 24780 2015-08-24 13:38:52 The equine forelimb suspensory ligament exhibits a heterogeneous strain pattern under tensile load Objectives: To determine if regional variations in strain patterns occur within the suspensory ligament under tensile load. Local increases in strain may put certain regions of the suspensory ligament at risk and may explain the poor healing and high recurrence rates associated with suspensory branch injuries. Methods: The suspensory ligament and its bone attachments were isolated from each of 10 adult equine cadaveric forelimbs and radiodense reference beads were inserted throughout the length of the ligament. Specimens were attached to a custom fixture secured to a materials testing system. Radiographs were acquired at 50, 445, 1112, and 2224 N of applied tensile load. Changes in distances between the beads in each region of the suspensory ligament were measured and the regional strain was calculated. Significant differences were determined using a repeated-measures analysis of variance. Results: The suspensory ligament exhibited significant differences in regional strain (p  M. Lavagnino (1), J. Madison (1), M. R. Williams (1), S. P. Arnoczky (1) 24661 2015-07-29 13:54:22 Variability of vertical ground reaction forces collected with one and two force plates in healthy... Objective: To compare peak vertical force (PVF) and vertical impulse (VI) data collected with one and two force plates during the same collection time period in healthy dogs at a trot. Animals: Seventeen healthy client-owned adult dogs. Methods: Vertical ground reaction force (GRF) data were collected in a crossover study design, with four sessions on two consecutive days, and then two weeks apart (days 1, 2, 15, and 16) using both one and two force plates collection methods. A repeated measures model analysis of variance (ANOVA) was used to test for differences in force plate PVF, VI, and average time per trial (ATT) between days, weeks, and systems (1 plate versus 2 plates). Coefficients of variation for PVF and VI were also calculated separately by forelimbs and hindlimbs, plates, day, and week. Results: The time required to obtain a valid trial was significantly longer using a single force plate when compared with two force plates. Comparing GRF data for all dogs, significant differences in PVF data were found between one and two force plates, however, these differences were diminutive in absolute magnitude, and of unknown clinical importance. Examination of the coefficients of variation for PVF and VI during the different collection periods yielded similar results. Conclusions: Use of two force plates decreased trial repetition and collection time. Vertical GRF data had a similar coefficient of variation with either one or two force plates collection techniques in healthy dogs.... M. Stejskal (1), B. T. Torres (1), G. S. Sandberg (1), J. A. Sapora (1), R. K. Dover (1), S. C. Budsberg (1) 24660 2015-07-29 13:52:49 The use of low doses of acepromazine as an aid for lameness diagnosis in horses: An accelerometric... Objectives: The aim of the present study was to quantify by accelerometry the trotting pattern of adult horses sedated with two different doses of acepromazine, in order to assess the use of this drug in equine lameness evaluations. Methods: Seven mature horses were used and three treatments were administered to each horse: saline solution, acepromazine (0.01 mg/kg), and acepromazine (0.02 mg/kg). The portable gait analyzer used consisted of three orthogonal accelerometers that measure accelerations along the dorsoventral, longitudinal, and lateral axes. Baseline values were obtained and after treatment, accelerometric recordings were repeated every five minutes during the first 20 minutes after the injection and then every 10 minutes thereafter for two hours. Ground-to-lip distance was also measured. Results: Administration of acepromazine decreased some of the variables investigated and differences between doses were observed. Speed, stride frequency, and stride length were significantly reduced following treatments. For coordination parameters, no significant differences among values were observed. Energetic variables suffered only weak reductions whereas ground-to-lip distance values were significantly decreased up to 120 minutes after treatment. Clinical significance: Acepromazine produces significant alterations in the gait pattern with differences between doses, but it does not affect coordination variables in normal unexcited horses, and at a dose of 0.01 mg/kg may be the tranquilizer of choice for evaluating lameness in this setting.... F. J. López-Sanromán (1), D. Gómez Cisneros (1, 2), M. Varela del Arco (1), I. Santiago Llorente (1), M. Santos González (3) 24659 2015-07-29 13:51:32 Biomechanical comparison of two locking plate constructs under cyclic torsional loading in a... Objectives: The number of locking screws required per fragment during bridging osteosynthesis in the dog has not been determined. The purpose of this study was to assess the survival of two constructs, with either two or three screws per fragment, under cyclic torsion. Methods: Ten-hole 3.5 mm stainless steel locking compression plates (LCP) were fixed 1 mm away from bone surrogates with a fracture gap of 47 mm using two bicortical locking screws (10 constructs) or three bicortical locking screws (10 constructs) per fragment, placed at the extremities of each LCP. Constructs were tested in cyclic torsion (range: 0 to +0.218 rad) until failure. Results: The 3-screws constructs (29.65 ± 1.89 N.m/rad) were stiffer than the 2-screws constructs (23.73 ± 0.87 N.m/rad), and therefore, were subjected to a greater torque during cycling (6.05 ± 1.33 N.m and 4.88 ± 1.14 N.m respectively). The 3-screws constructs sustained a significantly greater number of cycles (20,700 ± 5,735 cycles) than the 2-screws constructs (15,600 ± 5,272 cycles). In most constructs, failure was due to screw damage at the junction of the shaft and head. The remaining constructs failed because of screw head unlocking, sometimes due to incomplete seating of the screw head prior to testing. Clinical significance: Omitting the third innermost locking screw during bridging osteosynthesis led to a reduction in fatigue life of 25% and construct stiffness by 20%. Fracture of the screws is believed to occur sequentially, starting with the innermost screw that initially shields the other screws.... A. Bilmont (1), S. Palierne (1), M. Verset (1), P. Swider (2), A. Autefage (1) 24658 2015-07-29 13:50:24 Complications and outcome of a new modified Maquet technique for treatment of cranial cruciate... Objectives: To describe the complications, short and long-term outcome and owner satisfaction of dogs with cranial cruciate ligament rupture treated with a recently described new osteotomy for the modified Maquet technique (N-MMT). Materials and methods: Medical records and radiographs of 82 dogs (84 stifles) were reviewed. Details regarding short-term outcome and complications were recorded from the medical records. Long-term follow-up information was obtained by telephone interview. Historical data and complications were statistically analysed. Results: Major complications occurred in 34/84 stifles. Intra-operative complications occurred in 26/84 stifles, all of which were fissures or fractures of the cortical hinge. Twenty-one of these fractures or fissures were repaired with a figure-of-eight wire. The second most common major complication was late meniscal tears in 3/84 stifles. One dog sustained a complete tibial fracture. Non-displaced fracture of the cortical hinge was the most common postoperative minor complication, which occurred in 5/84 stifles. The median preoperative lameness score was 3 out of 6. Final in-hospital re-evaluation of limb function was available in 58 dogs. The median lameness score at that time was 0 out of 6. Development of osteotomy related complications was not associated with a significant change in the postoperative lameness score. Clinical significance: Subjectively assessed clinical outcome with the N-MMT was good to excellent in this cohort of dogs. However, a high rate of intra- and postoperative complications of the N-MMT procedure was also present in these dogs.... J. Ramirez (1), N. Barthélémy (2), S. Noël (2), S. Claeys (2), S. Etchepareborde (3), F. Farnir (4), M. Balligand (2) 24657 2015-07-29 13:47:27 Use of computed tomography to compare two femoral head and neck excision ostectomy techniques as... Objectives: To compare the results of femoral head and neck excision (FHNE) ostectomy performed by two novice veterinarians using an osteotome and mallet or microsagittal saw. Methods: In this ex vivo cadaveric study, hindlimbs of eight canine cadavers were randomized to FHNE with osteotome or micro sagittal saw as performed by two recently graduated veterinarians. The hindimbs were imaged by computed tomography (CT) before and after the osteotomy. Post FHNE CT images were evaluated by a board certified radiologist blinded to the ostectomy technique for assessment of the number of bone fragments, fissures, smoothness of osteotomy margination, and volume of residual femoral neck. Results: Femoral head and neck excision performed with the osteotome produced more peri-ostectomy bone fragments, cortical fissures, irregular margins, and residual femoral neck volume, compared with osteotomy using a saw. Clinical relevance: Compared to FHNE performed with a sagittal saw, osteotome FHNE resulted in a greater bone trauma and residual neck bone volume, which would require post-ostectomy modification in a clinical setting.... M. D. O'Donnell (1, 2), J. J. Warnock (1), G. Bobe (3), R. P. Scholz (1, 4), J. E. Wiest (1), S. Nemanic (1) 24628 2015-07-21 08:36:02 Biomechanical properties of the atlantoaxial joint with naturally-occurring instability in a toy... The biomechanical properties of the atlanto-axial joint in a young Yorkshire Terrier dog with spontaneous atlantoaxial instability were compared to those of another young toy breed dog with a healthy atlantoaxial joint. The range-of-motion was increased in flexion and lateral bending in the unstable joint. In addition, lateral bending led to torsion and dorsal dislocation of the axis within the atlas. On gross examination, the dens ligaments were absent and a longitudinal tear of the tectorial membrane was observed. These findings suggest that both ventral and lateral flexion may lead to severe spinal cord compression, and that the tectorial membrane may play a protective role in some cases of atlantoaxial instability. F. Forterre (1), C. Precht (2), B. Riedinger (1), A. Bürki (3) 24627 2015-07-21 08:35:04 Tibial anatomy in normal small breed dogs including anisometry of various extracapsular stabilizing... Objectives: To investigate proximal tibial anatomy and its influence on anisometry of extracapsular stabilizing sutures in small dog breeds. Materials and methods: Mediolateral radiographs of the femora, stifles, and tibiae of 12 small breed dogs were acquired with the stifles positioned at various angles. Measurements taken included tibial plateau angle (TPA), diaphyseal: proximal tibial angle (DPA), patellar tendon angle (PTA), Z-angle, relative tibial tuberosity width (rTTW), and the distance between six combinations of two femoral and three tibial extra-capsular stabilizing suture (ECS) attachment sites. Theoretical strain through stifle range-of-motion was recorded. Results: The TPA (32° ± 5.8°), DPA (10.2° ± 7.3°), PTA (103.7° ± 6.2°), and Z-angle (70.4° ± 9.0°) were positively correlated with one another (R >0.7), but none were correlated with rTTW (0.93 ±0.10). The F2-T1 combination of ECS attachment sites had lowest strain for nine stifles. The shortest attachment site separation was at a stifle flexion of 50° for nine stifles. Proximal tibial anatomy measurements could not predict optimal attachment site combination, optimal stifle angle for suture placement, or ECS strain. Clinical significance: There is individual variation in the optimal attachment site combination and stifle angle for suture placement, which may influence consistency of outcomes with ECS.... P. G. Witte (1) 24626 2015-07-21 08:31:52 Analysis of lactate concentrations in canine synovial fluid Objective: To report synovial fluid lactate concentrations in normal and pathological canine joints. Study design: Controlled, prospective study. Methods: Lactate was measured in synovial fluid using a hand-held meter and the rest of the fluid was sent to a commercial laboratory for analysis. Samples were divided into four groups; group 1: control, group 2: osteoarthritis, group 3: immune-mediated inflammatory arthritis, and group 4: septic arthritis. Statistical analysis was performed to compare lactate concentrations between the four groups and to examine the predictive value of lactate in the diagnosis of septic arthritis. A correlation was sought between synovial fluid lactate and synovial fluid total nucleated cell count and total protein. Results: Seventy-four samples were investigated from 55 dogs. Statistical analysis found that lactate concentrations were significantly higher in the septic arthritis group than in each of the other three groups. No significant correlation could be found between synovial fluid lactate concentrations and synovial fluid total nucleated cell count or synovial fluid total protein. Lactate concentration was found to be a useful predictor of septic arthritis, with a low concentration pointing towards exclusion rather than a high concentration to the diagnosis of septic arthritis. Clinical significance: Synovial fluid lactate concentration is not a good marker for osteoarthritis or immune-mediated inflammatory arthritis, but it is significantly increased in septic arthritis and could help the clinician in ruling out this condition in a quick and cost-effective way.... J. L. J. Proot (1), F. de Vicente (1), D. E. Sheahan (1) 24472 2015-06-10 11:44:13