Veterinary and Comparative Orthopaedics and Traumatology (VCOT) Veterinary and Comparative Orthopaedics and Traumatology (VCOT) vcot de-de Sat, 31 Jan 15 00:13:21 +0100 Ahead of print: Complete sequencing and characterization of equine aggrecan Objectives: To fully sequence and characterize equine aggrecan and confirm conservation of major aggrecanase, calpain and matrix metalloproteinase (MMP) cleavage sites. Methods: Reverse transcription-polymerase chain reaction and rapid amplification of cDNA ends were used to generate clones that encompassed the complete equine aggrecan sequence. Clones were sequenced and compared with the equine genome database to determine intron-exon boundaries. Results: The aggrecan gene spans over 61 kb on chromosome 1 and is encoded by 17 exons. Two major variants of aggrecan were cloned; one containing 8187 bp (2728 amino acids) and a second sequence of 8061 nucleotides (2686 amino acids). The variation was due to a CS1 domain polymorphism. Both sequences are substantially larger than predicted by the genomic database; 11 CS1 repeat elements are absent in the database sequence. The equine amino acid sequence was compared with human, bovine and murine sequences. Globular domains 1, 2 and 3 are highly conserved (overall identity over 80%). Equine CS1 is considerably larger than in other species and, therefore, is the least conserved domain (an overall amino acid identity of 22%). Previously defined aggrecanase, calpain and MMP cleavage sites were identified. Western blotting of chondrocyte culture samples showed complex post-secretion processing. Clinical significance: The complete equine aggrecan sequence will support more in-depth research on aggrecan processing and degradation in equine articular cartilage and other musculoskeletal tissues.... E. H. G. Caporali (1), T. Kuykendall (1), M. C. Stewart (1) 23951 2015-01-30 08:15:00 Ahead of print: The effect of intramedullary pin size and monocortical screw configuration on... Objective: To investigate the effect of intramedullary pin size in combination with various monocortical screw configurations on locking compression plate-rod constructs. Methods: A synthetic bone model with a 40 mm fracture gap was used. Locking compression plates with monocortical locking screws were tested with no pin (LCP-Mono) and intramedullary pins of 20% (LCPR-20), 30% (LCPR-30) and 40% (LCPR-40) of intramedullary diameter. Locking compression plates with bicortical screws (LCP-Bi) were also tested. Screw configurations with two or three screws per fragment modelled long (8-hole), intermediate (6-hole), and short (4-hole) plate working lengths. Responses to axial compression, biplanar four-point bending and axial load-to-failure were recorded. Results: LCP-Bi were not significantly different from LCP-Mono control for any of the outcome variables. In bending, LCPR-20 were not significantly different from LCP-Bi and LCP-Mono. The LCPR-30 were stiffer than LCPR-20 and the controls. The LCPR-40 constructs were stiffer than all other constructs. The addition of an intramedullary pin of any size provided a significant increase in axial stiffness and load to failure. This effect was incremental with increasing intramedullary pin diameter. As plate working length decreased there was a significant increase in stiffness across all constructs. Clinical Significance: A pin of any size increases resistance to axial loads whereas a pin of at least 30% intramedullary diameter is required to increase bending stiffness. Short plate working lengths provide maximum stiffness. However, the overwhelming effect of intramedullary pin size obviates the effect of changing working length on construct stiffness.... T. Pearson (1), M. Glyde (1), G. Hosgood (1), R. Day (2) 23950 2015-01-30 08:13:40 Ahead of print: Evaluation of the accuracy of a veterinary dynamometric wire tensioner Objectives: The purpose of this study was to determine the accuracy of a commonly used veterinary wire tensioner. Methods: Wire tension was measured using a load cell after each of five tensioners were used to tension each of six wires to the 66, 84, and 118 mm ring settings in an adjustable custom testing fixture. Each tensioner then experienced simulated aging and testing was repeated. Percentage error was calculated for each ring size, before and after tensioner aging. Measured tension values were compared to manufacturer reported tension values for each ring size using a one-sample two-way t-test; p <0.05 was considered significant. Results: Compared to the manufacturer reported values, measured wire tension values were significantly lower for 66 mm and 84 mm rings and significantly higher for 118 mm rings, before and after simulated aging. Mean wire tension values did not significantly differ between individual wire tensioners. Clinical significance: The tensioners tested achieved significantly different wire tension values than those reported by the manufacturer. This discrepancy could lead to under-tensioning and allowing excessive movement at a fracture site or over-tensioning, leading to wire breakage. We recommend tensioning wires at least to the recommended line on the device for 66 mm and 84 mm rings and at most to the recommended line for 118 mm rings. Further studies are needed to evaluate other veterinary wire tensioners and to develop a calibration method for these devices in practice.... C. M. Gauthier (1), K. McGilvray (2), S. Myrick (3), F. Duerr (1), R. Palmer (1) 23949 2015-01-30 08:12:27 Cementless Total Hip Replacement Complications K. A. Johnson 23887 2015-01-12 14:53:17 Computed tomographic evaluation of elbow congruity during arthroscopy in a canine cadaveric model Objective: To assess the effect of arthroscope insertion, using a carbon-fibre rod model, on humero-radial, humero-ulnar and radio-ulnar congruity, as assessed by computed tomography (CT). Methods: Cadaveric Greyhound elbow joints were assessed at a flexion angle of 135 ± 5° using CT. For condition 1, a 36 mm fulcrum induced cubital valgus, as used to aid arthroscope insertion. For conditions 2 and 3, a single 1.8 or 2.5 mm diameter rod was inserted under arthroscopic guidance to simulate arthroscope position for assessment of the medial coronoid process. Repeat CT scans were obtained for all conditions and parasagittal sections were reconstructed to evaluate medial, axial and lateral positions within the elbow. Humero-radial, humero-ulnar, and radio-ulnar congruity measurements were obtained. Differences between groups were assessed using repeated measures analysis of variance. Results: Mean (±SD) change in radio-ulnar step between conditions 1 and 3 was 0.6 ± 0.3 mm (axial), 0.8 ± 0.6 mm (medial), and 0.5 ± 0.1 mm (lateral). Insertion of rods induced a significant decrease in radio-ulnar step in all planes. Significant differences were also identified between groups for humero-radial, humero-ulnar, and radio-ulnar congruity. Clinical significance: Insertion of carbon-fibre rods as a model for elbow arthroscope insertion induces elbow incongruity. Changes in radio-ulnar congruity are small but the effect of arthroscope diameter should be considered when assessing elbow congruity.... O. T. Skinner (1), C. M. R. Warren-Smith (1), N. J. Burton (1), K. J. Parsons (1) 23818 2014-12-09 10:20:56 Congenital cervical kyphosis in two young sighthounds Introduction: Cervical vertebral (C) malformation is rarely reported in large breed dogs. Congenital cervical kyphosis (CCK) may result from defects of vertebral segmentation, failure of formation or both. This report describes two cases of C3-C4 CCK in young sighthounds, treated surgically. Case description: An 18-month-old female Deerhound and a six-week-old female Borzoi dog were presented because of the complaints of reluctance to exercise and signs of of neck pain. Both dogs were neurologically normal. Diagnostic imaging revealed C3-C4 deformity, moderate kyphosis, and spinal canal stenosis associated with chronic spinal cord pressure atrophy. Both dogs underwent surgical treatment. Results: A staged two-step surgery starting with dorsal decompression was elected in the Deerhound. After the first surgical procedure, the dog developed focal myelomalacia and phrenic nerve paralysis and was euthanatized. A ventral distraction-fusion technique with two locking plates was performed in the Borzoi. This patient recovered uneventfully and long-term follow-up computed tomography revealed complete spondylodesis. Clinical significance: Until now, CCK has only been described in sighthounds. Congenital cervical kyphosis might be considered a differential diagnosis in these breeds that are presented with signs of cervical pain. Ventral realignment-fusion and bone grafting may be considered for surgical treatment, although the earliest age at which this procedure can and should be performed remains unclear.... F. Forterre (1), D. Casoni (2), A. Tomek (3), P. Karli (3), J. Howard (4), C. Precht (5) 23817 2014-12-09 10:19:47 Influence of calibration protocols for a pressure-sensing walkway on kinetic and temporospatial... Objectives: To evaluate the influence on the kinetic and temporospatial parameters of calibration protocols with point and step techniques for a pressure-sensing walkway. Methods: Nine Labrador dogs were used. Two protocols of point calibration technique (C1 and C2) and eight protocols of step calibration technique (C3 to C10) were performed. In C1, weight was added to a stool to match the body mass of each dog. In C2, weight was added to the stool to match a 46.1 kg person. The other eight calibration protocols represented combinations of the following factors: 46.1 kg and 96.1 kg persons, barefoot or wearing sneakers, and stepping onto the platform with one or two feet. Results: The calibration protocols did not affect the temporospatial variables or percentages of body weight (%BW) distribution. Significant differences were found in both PVI (peak vertical force) and VI (vertical impulse) between barefoot versus wearing sneakers, 46.1 kg versus 96.1 kg person, and stepping onto the platform with one foot versus two feet. When comparing C1 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs. When comparing C2 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs in all protocols. Clinical significance: The PVF and VI were influenced by the calibration protocol used, but the %BW distribution and temporospatial parameters were not. Using the same calibration protocol for all dogs within the same group eliminated the variability of the kinetic data caused by the calibration.... F. S. Agostinho (1), S. C. Rahal (1), B. Geraldo (1), P. L. T. Justolin (1), C. R. Teixeira (1), F. L. M. L. Lins (2), F. O. B. Monteiro (2) 23786 2014-12-02 11:10:44 Ahead of print: Pedicle digital pad transfer and negative pressure wound therapy for reconstruction... A young Labrador Retriever was presented for treatment of severe distal hindlimb necrosis caused by bandage ischemia. During digit amputation at the metatarsophalangeal joints, the third and fourth digital pads were salvaged and transferred to the metatarsal stump to create a weight-bearing surface. Negative pressure wound therapy (NPWT) was utilized for flap immobilization and to promote granulation tissue in the remaining wound defect. Sturdy adherence of the digital pads was achieved after only four days. The skin defect healed completely by second intention and the stump was epithelialized with a thin pad after three months. At the nine month follow-up examination, the stump had a thick hyperkeratinized pad. The dog walked and ran without any apparent signs of discomfort and compensated for the loss of limb length by extending the stifle and tarsocrural joints. Despite a challenging wound in a difficult anatomical location, digital pad flap transfer and NPWT proved successful in restoring long-term ambulation in an active large breed dog.... M. Or (1), B. Van Goethem (1), I. Polis (1), A. Spillebeen (1, 2), P. Vandekerckhove (3), J. Saunders (4), H. de Rooster (1) 23785 2014-12-02 11:09:59 A review of canine atlantoaxial joint subluxation Atlantoaxial subluxation was first reported in dogs nearly fifty years ago. Since that time a better understanding of the aetiologies predisposing to joint laxity and instability has been achieved. Surgeons however are still trying to address the problems associated with stabilizing this joint which by nature is often required in small juvenile dogs. This review describes the various techniques used, discussing the associated benefits and complications thereby allowing the clinician to make an informed decision on the best treatment for the individual patient. C. Stalin (1), R. Gutierrez-Quintana (1), K. Faller (1), J. Guevar (1), C. Yeamans (1), J. Penderis (1) 23784 2014-12-02 11:09:02 Acetabular cup liner and prosthetic head exchange to increase the head diameter for management of... 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).... S. C. Roe (1), C. Sidebotham (2), D. J. Marcellin-Little (1) 23783 2014-12-02 11:07:49 Negative pressure wound therapy, silver coated foam dressing and conventional bandages in open wound... Objectives: To evaluate negative pressure wound therapy (NPWT) for treatment of complicated wounds in dogs. Study type: Retrospective multicentre study. Materials and methods: Dogs (n = 50) undergoing open wound treatment were classified according to treatment method used: bandage (Group A, n = 7), NPWT (Group B, n = 18), and foam dressing (Group C, n = 25). Pairs of patients matched based on wound conformation, localization, and underlying cause were compared between Group A and C (n = 7 pairs) and between groups B and C (n = 18 pairs) in terms of duration of previous treatment, time to closure, and complications. Results: Signalment, antibiotic medications, antiseptic treatment, and bacterial status of wounds were comparable between groups. The duration of previous treatment was significantly higher in patients assigned to Group B (p = 0.04) compared to Group C, while no significant difference was found between groups A and B. Total time to wound closure was significantly shorter in Group C compared to Group A (p = 0.02) and in Group B compared to Group C (p = 0.003). Wounds treated with NPWT suffered significantly less complications (p = 0.008) and were significantly less septic during treatment (p = 0.016) than wounds treated with a foam dressing. Conclusion: This study shows that time to healing was halved in NPWT treated patients compared to foam dressing treated patients, which in turn healed faster than patients treated with conventional bandage, underlining the value of NPWT therapy for the treatment of complicated wounds.... M. C. Nolff (1), M. Fehr (2), A. Bolling (2), R. Dening (2), S. Kramer (2), S. Reese (3), A. Meyer-Lindenberg (1) 23782 2014-12-02 11:06:25 Healing Large Bone Defects K. A. Johnson 23704 2014-11-18 10:17:47 Arthrodesis of the proximal interphalangeal joints of a hindlimb in a heifer A two-year-old Braunvieh heifer was presented with a traumatic luxation of the second phalanx of the medial digit and concurrent subluxation of the second phalanx of the lateral digit of the right hindlimb. Closed reduction of both luxations was possible. Surgical arthrodesis was achieved using one narrow 4.5 mm three-hole equine locking compression plate for each joint. Placement of the bone plates resulted in stable arthrodesis of both proximal interphalangeal joints of the right hindlimb but there was persistent residual lameness. The heifer delivered a healthy calf but was slaughtered eight months after surgery because of varus deformity of the contralateral limb. Radiographs taken post-mortem revealed pronounced periosteal reactions involving both proximal interphalangeal joints and only partial bony bridging of the joint spaces. E. Muggli (1), E. Weidmann (1), A. Bruderer (1), K. Nuss (1) 23690 2014-11-14 08:57:28 Risk factors for loosening of cementless threaded femoral implants in canine total hip arthroplasty Objective: To determine the incidence and potential risk factors of femoral implant loosening in the canine Helica® total hip replacement (THR) system. Method: Sixteen dogs with a Helica THR were included. Medical records were reviewed for signalment and size of implants. Stem angle, stem collar to lateral cortex distance, tip to cortex distance, stem collar to lateral cortex distance at a stem angle of 150°, lever arm distance, and the distance on the diaphysis measurements were calculated from the one year postoperative radiographs. Three ratios were determined from these measurements to take into account the size of the femur in relation to the size of the implant. Femoral implant loosening was identified by radiographic and clinical signs, and confirmed at the time of surgical explantation. Differences in the successful and femoral stem failure groups were compared using either a students t-test or a Mann Whitney test. Significance was set at p K. A. Agnello (1), D. Cimino Brown (1), K. Aoki (2), S. Franklin (3), K. Hayashi (4) 23689 2014-11-14 08:56:24 Ex vivo kinematic studies of a canine unlinked semi-constrained hybrid total elbow arthroplasty... Objectives: Introduction of the Sirius® canine total elbow arthroplasty system, and presentation of the results of a passive range-of-motion analysis based on ex vivo kinematic studies pre-and post-implantation. Materials and methods: Thoracic limbs (n = 4) of medium sized dogs were harvested by forequarter amputation. Plain orthogonal radiographs of each limb were obtained pre- and post-implantation. Limbs were prepared by placement of external fixator pins and Kirschner wires into the humerus and radius. Each limb was secured into a custom-made box frame and retro-reflective markers were placed on the exposed ends of the pins and wires. Each elbow was manually moved through five ranges-of-motion manoeuvres. Data collected included six trials of i) full extension to full flexion and ii) pronation and supination in 90° flexion; a three-dimensional motion capture system was used to collect and analyse the data. The Sirius elbow prosthesis was subsequently implanted and the same measurements were repeated. Data sets were tested for normality. Paired t-tests were used for comparison of pre- and post-implantation motion parameters. Results: Kinematic analysis showed that the range-of-motion (mean and SD) for flexion and extension pre-implantation was 115° ± 6 (range: 25° to 140°). The range-of-motion in the sagittal plane post-implantation was 90° ± 4 (range: 36° to 130°) and this reduction was significant (p = 0.0001). The ranges-of-motion (mean and SD) for supination and pronation at 90° were 50° ± 5, whereas the corresponding mean ranges-of-motion post-implantation were 38° ± 6 (p = 0.0188). Conclusion: Compared to a normal elbow, the range-of-motion was reduced. Post-implantation, supination and pronation range-of-motion was significantly reduced at 90° over pre-implantation values. Clinical relevance: These results provide valuable information regarding the effect of the Sirius system on ex vivo kinematics of the normal canine elbow joint. Further, this particular ex vivo model allowed for satisfactory and repeatable kinematic analysis.... N. D. Lorenz (1), S. Channon (2), R. Pettitt (1), P. Smirthwaite (3), J. F. Innes (1, 4) 23688 2014-11-14 08:55:26 Erosion of the medial compartment of the canine elbow: occurrence, diagnosis and currently available... Erosion of the medial compartment of the elbow joint refers to full thickness cartilage loss with exposure of the subchondral bone (modified Outerbridge grades 4–5) of the medial part of the humeral condyle (MHC) and the corresponding ulnar contact area. This finding may appear in the absence of an osteochondral fragment or a cartilage flap, or in combination with fragmentation of the medial coronoid process (MCP) or osteochondritis dissecans (OCD) of the MHC. With regard to the prognosis, it is important to diagnose these severe erosions. Imaging of cartilage lesions by means of radiography, ultrasonography, computed tomography or magnetic resonance imaging is challenging in dogs. In contrast, direct arthroscopic inspection provides detailed information about the cartilage. The treatment of these severe erosions is difficult because of the limited regenerative capacity of cartilage and presumed mechanical or physical triggering factors. Several conservative and surgical treatment methods have been proposed to treat elbows with severe cartilage defects. However, due to irreversible loss of cartilage, the prognosis in these cases remains guarded.... E. Coppieters (1), I. Gielen (1), G. Verhoeven (1), D. Van Vynckt (1), B. Van Ryssen (1) 23687 2014-11-14 08:54:30 Revision of a loose cementless short-stem threaded femoral component using a standard cementless... 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. S. C. Roe (1), D. J. Marcellin-Little (1), B. D. X. Lascelles (1) 23686 2014-11-14 08:52:55 A comparison of conventional compression plates and locking compression plates using cantilever... Objectives: The purpose of this study was to compare the stiffness, yield load, ultimate load at failure, displacement at failure, and mode of failure in cantilever bending of locking compression plates (LCP) and dynamic compression plates (DCP) in an acute failure ilial fracture model. Our hypothesis was that the LCP would be superior to the DCP for all of these biomechanical properties. Methods: Ten pelves were harvested from healthy dogs euthanatized for reasons unrelated to this study and divided into two groups. A transverse osteotomy was performed and stabilized with either a 6-hole DCP applied in compression or a 6-hole LCP. Pelves were tested in cantilever bending at 20 mm/min to failure and construct stiffness, yield load, ultimate load at failure, displacement at failure, and mode of failure were compared. Results: The mean stiffness of DCP constructs (193 N/mm [95% CI 121 – 264]) and of LCP constructs (224 N/mm [95% CI 152 – 295]) was not significantly different. Mean yield load of DCP constructs (900 N [95% CI 649 –1151]) and of LCP constructs (984 N [95% CI 733 –1235]) was not significantly different. No significant differences were found between the DCP and LCP constructs with respect to mode of failure, displacement at failure, or ultimate load at failure. Clinical significance: Our study did not demonstrate any differences between DCP and LCP construct performance in acute failure testing in vitro.... C. W. Bruce (1), T. W. G. Gibson (2), R. J. Runciman (3) 23615 2014-10-27 08:48:08 Kinematic gait analysis of the canine thoracic limb using a six degrees of freedom marker set Objectives: To determine if the use of a six degrees of freedom marker set would allow new kinematic data of the canine thoracic limbs to be calculated. To identify any significant differences in thoracic limb gait patterns in all planes of motion, between the normal canine population and patients with confirmed medial coronoid disease (MCD). Method: Two groups of dogs were selected representing the normal Labrador Retriever population (n = 13) and Labrador Retrievers with confirmed MCD (n = 13). Normal dogs had “normal” hip and elbow radiographic scores in line with the International Elbow Working Group and British Veterinary Association guidelines. Medial coronoid disease was confirmed using arthroscopy after kinematic analysis was performed with a six degrees of freedom marker set. Results: The diseased elbow was nine degrees more extended between 43%-55% of the gait cycle and 16° more supinated prior, early during and after foot strike. The antebrachium was nine degrees more supinated during foot strike and three degrees more abducted during early stance. None of the other parameters were significantly different. Clinical significance: The use of a six degrees of freedom marker set made it possible for the elbow and antebrachium to be reliably tracked in more than one plane of motion. Significant differences were identified between the normal canine population and those affected by MCD. These data may help elucidate biomechanical factors contributing to aetiopathogenesis of MCD.... A. Caron (1), A. Caley (2), M. Farrell (1), N. Fitzpatrick (1) 23614 2014-10-27 08:46:47 Treatment of canine cranial cruciate ligament disease Objective: To describe veterinarians’ treatment recommendations and decision-making factors for dogs with cranial cruciate ligament disease (CCLD). Methods: An online survey of American College of Veterinary Surgeons (ACVS)-Diplomates (surgeon group) and primary care veterinarians (practitioner group) was performed. The survey included questions on treatment recommendations for common case scenarios (small or large breed dog with complete or partial CCLD), treatment decision factors, non-surgical treatment options, and actual treatment, if any, provided for a client-owned dog as well as one owned by their family or close friend. Results: The response rate was 42% for the surgeon group (n = 305/723) and four percent for the practitioner group (n = 1145/ 27,771). Extracapsular stabilization (ES) was the most common treatment recommendation for CCLD in small (9.1 kg) breed dogs amongst surgeons and practitioners. Tibial plateau levelling osteotomy (TPLO) was the most common treatment recommendation for CCLD in large (27.2 kg) breed dogs amongst both groups. The two most important treatment decision factors were dog size (78% of practitioners, 69% of surgeons) and activity level (63% of practitioners, 52% of surgeons). The most common treatment provided for a dog of their own or close relation in the surgeon group was TPLO (64%) followed by ES (15%), whereas in the practitioner group it was ES (38%) followed by TPLO (30%). Clinical significance: Extracapsular stabilization and TPLO are the most commonly employed surgical procedures in the surveyed population; dog size and activity level (but not age) are the major factors influencing treatment decisions.... F. M. Duerr (1), K. W. Martin (1), M. Rishniw (2), R. H. Palmer (1), L. E. Selmic (1) 23607 2014-10-20 10:52:37 Medullary cavity diameter of metacarpal and metatarsal bones in cats Objectives: To compare radiography and computed tomography (CT) for the evaluation of medullary cavity diameters of metacarpal and metatarsal bones in cats and to analyse their correlation with intramedullary pin size. Methods: Radiography and CT were performed in cadavers (n = 12). The mid-diaphysis was determined and the medullary cavity diameter was measured by two observers. Each bone was osteotomized at the mid-diaphysis, Kirschner wires were inserted, and pin size was documented. Intra- and interobserver variability was evaluated (hierarchical analysis of variance). Radiography and CT were compared (correlation analysis, a t-test for dependent samples, a Bland-Altman analysis) and pin size, radiography and CT were compared (regression and correlation analysis). Results: Intra-observer variability was low for radiographs and CT, with an estimated median variation of 0.10 mm for radiographs and 0.12 mm for CT. Inter-observer variability was low, with a median variation of 0.03 mm for radiographs and 0.21 mm for CT. There was a high correlation between radiography and CT for the assessment of the medullary cavity diameter. A high correlation was found between pin size and measurement on radiographs, and between pin size and measurements on CT. In two cats, pin insertion was difficult or impossible. Clinical significance: Mid-diaphyseal meas-urements are applicable methods for the assessment of the medullary cavity diameter in feline metacarpal and metatarsal bones regarding intramedullary pins. In some cats the medullary cavity diameter may be too small for intramedullary pinning techniques, which can be identified preoperatively on radiographs.... M. Kornmayer (1), K. Amort (1), K. Failing (2), M. Kramer (1) 23606 2014-10-20 10:50:16 Lameness associated with tarsal haemarthrosis as the sole clinical sign of idiopathic... A four-year-old, male Cocker Spaniel was presented for investigation of pelvic limb stiffness. There was palpable effusion of both tarsi, and analysis of synovial fluid from these joints indicated previous haemorrhage. After further investigation a diagnosis of idiopathic immune-mediated thrombocytopenia was made. The dog responded to treatment with prednisolone and azathioprine. To the authors’ knowledge, this is the first reported case of confirmed haemarthrosis as the sole presenting clinical sign for canine idiopathic immune-mediated thrombocytopenia. M. B. Walton (1), E. Mardell (2), M. Spoor (3), J. Innes (1) 23605 2014-10-20 10:28:01 Kinetic and kinematic evaluation of compensatory movements of the head, pelvis and thoracolumbar... Objectives: To determine ground reaction forces, head and pelvis vertical motion (HVM and PVM, respectively), and thoraco-lumbar lateral angular motion (LAM) of the spine using kinematic gait analysis in dogs with mild asymmetric weight-bearing of the pelvic limbs while trotting. Methods: Twenty-seven hound-type dogs were fitted with reflective markers placed on the sagittal crest of the skull, the ischiatic tuberosity, and thoracolumbar spine of dogs to track motion while trotting. Kinetic and kinematic data were used to characterize asymmetry between the left and right pelvic limbs, and to describe HVM, PVM and thoraco-lumbar LAM. Maximum and minimum position and total motion values were determined for each measured variable. Results: Dogs with asymmetric weight bearing of the pelvic limbs had greater PVM on the side with a greater peak vertical force (PVF), and greater thoraco-lumbar LAM toward the side with a lower PVF while trotting. No differences in mean HVM were detected, and there were no significant correlations between the magnitude of HVM, PVM and thoraco-lumbar LAM and the degree of asymmetric weight bearing. Clinical significance: Dogs with subtle asymmetric weight bearing of a pelvic limb had patterns of body motion that may be useful in identifying subtle lameness in dogs; greater PVM on the side with greater weight bearing and greater thoraco-lumbar LAM toward the side with less weight bearing while trotting. Description of these compensatory movements is valuable when evaluating dogs with subtle weight bearing asymmetry in the pelvic limbs and may improve the sensitivity of lameness detection during subjective clinical lameness examination.... D. A. Hicks (1), D. L. Millis (2) 23604 2014-10-20 10:27:09 Effect of tibial subluxation on the measurements for tibial tuberosity advancement in dogs with... Objectives: The main objectives were to evaluate the impact of femorotibial subluxation on the preoperative measurements for tibial tuberosity advancement (TTA) by defining radiographic landmarks and testing the repeatability for assessing cranial tibial subluxation (CTS). Also, we aimed at developing a formula to calculate the necessary adjustment in measurement of TTA in stifles with CTS. Methods: Forty stifles were used to examine the influence of CTS on preoperative TTA measurements before and after transection of the cranial cruciate ligament. Mediolateral radiographs were obtained and measurements performed by three investigators. The observed variabilities were assessed by inter- and intra-observer differences. Results: Measurements of CTS and preoperative TTA showed a good to excellent inter- and intra-observer correlation. We found a significant influence of CTS on TTA measurements and developed a formula to calculate the necessary adjustment in measurement of TTA in stifles with CTS. Conclusion: We found a correlation between the tibial subluxation and the measurements for TTA, with the latter decreasing with increasing subluxation. This has to be taken into account when measuring the advancement in stifles with complete rupture of the cranial cruciate ligament. We provided a formula to calculate the necessary addition to the measured advancement.... M. J. Bielecki (1), C. S. Schwandt (1), S. Scharvogel (1) 23603 2014-10-20 10:26:09 Computed tomography assisted determination of optimal insertion points and bone corridors for... Objective: Describe optimal corridors for mediolateral or lateromedial implant placement in the feline tarsus and base of the metatarsus. Methods: Computed tomographic images of 20 cadaveric tarsi were used to define optimal talocalcaneal, centroquartal, distal tarsal, and metatarsal corridors characterized by medial and lateral insertion points (IP), mean height, width, length and optimal dorsomedial-plantarolateral implantation angle (OIA). Results: Talocalcaneal level: The IP were at the head of the talus and plantar to the peroneal tubercle of the calcaneus and OIA was 22.7° ± 0.3. Centroquartal level: The IP were at the centre of the medial surface of the central tarsal bone and dorsoproximal to the tuberosity of the fourth tarsal bone and OIA was 5.9° ± 0.06. Distal tarsal level: The IP were at the centre of the medial surface of the tarsal bone II and dorsodistal to the tuberosity of the fourth tarsal bone and OIA was 5.4° ± 0.14. Metatarsal level: The IP were at the dorsomedial surface of the proximal end of the metatarsal bone II and at the dorsolateral surface of metatarsal bone V and OIA was 0.5° ± 0.06. Significant positive correlation was found between body weight and the length of each corridor. Clinical significance: Most of the corridors obtained in this study had a diameter between 1.5 mm and 2 mm with a length of 15 mm to 18 mm, which stresses the importance of their accurate placement.... M. Benlloch-Gonzalez (1), M. Grapperon-Mathis (1), B. Bouvy (2) 23602 2014-10-20 10:25:10