Veterinary and Comparative Orthopaedics and Traumatology (VCOT) Veterinary and Comparative Orthopaedics and Traumatology (VCOT) vcot de-de Fri, 27 Feb 15 06:58:05 +0100 Ahead of print: Augmentation of diaphyseal fractures of the radius and ulna in toy breed dogs using... Objectives: Evaluation of the short-term outcome, duration of bone healing, and complications following bone plate fixation in dogs weighing ≤6 kg, with and without the use of a free autogenous greater omental graft (OG). Materials and methods: A retrospective clinical study reviewed the medical records of 25 dogs of body weight <6 kg with mid to distal diaphyseal fractures of the radius and ulna (29 fractures) treated with open reduction bone plate fixation. Thirteen out of 29 fractures were implanted with an additional 2–3 cm³ OG lateral, cranial, and medial to the fracture site, adjacent to the bone plate. Results: Median time to radiographic healing in OG fractures (n = 11) was 70 days (range 28–98) compared to 106 days (range: 56–144) in non-OG grafted fractures (n = 14). The OG dogs had no major complications; minor complications included oedema, erythema, and mild osteopenia. Six of the eight non-OG dogs for which follow-up could be obtained developed osteopenia necessitating implant removal, four of which re-fractured the radius one to five months after implant removal, with one dog re-fracturing the limb a second time and resulting in amputation. Telephone follow-up of owners of OG dogs (n = 11) three to 15 months (median 10) post-surgery did not identify any signs of lameness or other complications. Owners of the non-OG dogs (n = 8) reported that there were not any signs of lameness six to 48 months (median 36) post-surgery. Clinical relevance: Free autogenous omental grafting of diaphyseal fractures of the radius and ulna was associated with radial and ulnar healing with minimal complications in dogs weighing less than 6 kg.... W. I. Baltzer (1), S. Cooley (2), J. J. Warnock (1), S. Nemanic (1), S. M. Stieger-Vanagas (1) 24045 2015-02-23 08:54:26 Ahead of print: Mechanical performance in axial compression of a titanium polyaxial locking plate... Objective: To evaluate the bending strength of the VetLOX® polyaxial locking plate system Materials and methods: Thirty-five 3.5 mm 12-hole titanium VetLOX® plates were used to stabilize seven different construct designs in a 1 cm fracture gap simulation model. Each construct was subjected to axial compression. Mean bending stiffness (BS) and yield load (YL) of each construct design were analysed using a one-way ANOVA and Tukey post-hoc analysis. Screw angulation was measured on reconstructed computed tomography (CT) images. Results: Reducing plate working length for fixed-angle constructs significantly increased BS (p <0.01) and YL (p <0.01). For a constant plate working length, increasing screw number did not significantly affect BS (p = 1.0) or YL (p = 0.86). Screw angulation measurement technique was validated by intra-class correlation coefficients (ICC) (ICC >0.9 for inter- and intra-observer measurements). An average screw angle of 13.2° did not significantly affect mechanical performance although incomplete screw head-plate engagement was noted on some reconstructed CT images when angulation exceeded 10°. Prefabricated screw-head inserts did not significantly increase mechanical performance. A 4 mm bone-plate stand-off distance significantly reduced BS and YL by 63% and 69% respectively. Clinical relevance: The VetLOX® system allows the benefits of polyaxial screw insertion whilst maintaining comparable bending properties to fixed angle insertion. The authors recommend accurate plate contouring to reduce the risk of plate bending.... A. W. Tomlinson (1), E. J. Comerford (1, 2), R. S. Birch (3), J. F. Innes (4), M. B. Walton (4) 24044 2015-02-23 08:53:31 Ahead of print: Femoral nerve entrapment in a dog with diffuse idiopathic skeletal hyperostosis Objective: To report femoral neuropathy caused by nerve entrapment associated with diffuse idiopathic skeletal hyperostosis (DISH). Study Design: Case report. Animal: Seven-year-old female spayed Boxer dog. Results: Entrapment of the right femoral nerve due to DISH caused a femoral nerve deficit and atrophy of muscle groups associated with the affected nerve. A combination of computed tomography and magnetic resonance imaging was performed to provide a diagnosis. Amputation of the right transverse process of the sixth lumbar vertebra at the level of nerve entrapment relieved the neurological abnormality. Conclusions: Nerve entrapment leading to neurapraxia may occur concurrently with DISH and surgery in this case was successful in restoring function. Clinical relevance: Peripheral neuropathy from nerve entrapment should be considered in patients with DISH. Surgical amputation of impinging osseous structures may be indicated for relief of femoral neuropathy. A. Lai (1), J. Culvenor (1), C. Bailey (1), S. Davies (2) 23964 2015-02-04 14:53:04 Ahead of print: Bilateral cervical ribs in a Dobermann Pinscher An 11-year-old intact female Doberman Pinscher was presented with the complaint of non-ambulatory tetraparesis.Clinical and neurological examination revealed a caudal cervical spinal cord disfunction (C6-T2 spinal cord segments). Magnetic resonance imaging and computed tomographic (CT) findings of the cervical spine were consistent with caudal cervical spondylomyelopathy (CSM). During the diagnostic work-up for the cervical spine, bilateral bone anomalies involving the seventh cervical vertebra and the first ribs were found on radiographs and CT examination.The rib anomalies found in this dog appear similar to cervical ribs widely described in human medicine. In people, cervical ribs are associated with a high rate of stillbirth, early childhood cancer, and can cause the thoracic outlet syndrome, characterized by neurovascular compression at level of superior aperture of the chest. In dogs, only some sporadic anatomopathological descriptions of cervical ribs exist. In this report the radiographic and CT findings of these particular vertebral and rib anomalies along with their relationships with adjacent vasculature and musculature are shown intravitam in a dog. Specific radiographic and CT findings described in this report may help in reaching a presumptive diagnosis of this anomaly. Finally, their clinical and evolutionary significance are discussed.... M. Ricciardi (1), A. De Simone (1), F. Gernone (1), P. Giannuzzi (1) 23963 2015-02-04 14:52:23 Ahead of print: Patellar groove replacement in patellar luxation with severe femoro-patellar... Objective: To report a novel method of treating femoro-patellar instability in association with severe femoro-patellar osteoarthritis, by substituting the femoral trochlear with a patellar groove replacement prosthesis. Study design: Retrospective case series. Methods: Preoperative lameness was scored from 0–4, and radiographic studies including standard positions for patellar luxation were obtained for evidence of malalignment and femoro-patellar osteoarthritis. Cases with or without previous surgeries were included. The size of trochlear implant was determined by transparent templates and confirmed intra-operatively with trials. Radiographic images, together with clinical examinations, were reviewed immediately and at three months postoperatively and at longer term when available. Results: Thirty-five cases of patellar luxation ranging from grades II to IV were included. Eleven of these cases had prior surgical interventions which failed to stabilize the patella. Fourteen dogs required additional surgical procedures in conjunction with patellar groove replacement. Complications occurred in six patients, of which three required revision. Complete resolution of subjectively-assessed lameness was evident in 24/35 cases by the third month and in another seven of 35 patients on the longer term re-evaluations. Clinical significance: Use of a patellar groove replacement prosthesis has the potential to decrease the lameness associated with severe femoro-patellar arthritis, to improve patellar stability, and to correct the alignment of the extensor mechanism.... Z. Dokic (1), D. Lorinson (1), J. Weighel (2), A. Vezzoni (3) 23962 2015-02-04 14:51:36 Ahead of print: Impact of fixation method on postoperative complication rates following surgical... Objectives: To compare the complication rate between open reduction and internal fixation (ORIF) and external skeletal fixation (ESF) for feline diaphyseal tibial fractures. Methods: In a retrospective study spanning a 10 year period, 57 feline tibial fractures stabilized via ESF or ORIF were included for analysis and complication rates were compared between the two methods. Results: In the overall study population, 23 (40.4%) cases suffered complications (9 major, 20 minor, 6 with both major and minor). All of the major complications occurred in the ESF group. Complications were more common in cats with ESF (50.0%) while only one (7.7%) of the ORIF cases suffered complications (OR 12.0 [CI: 2.09; 228.10], p = 0.02). Use of postoperative antibiotic medications was identified as a confounder. After adjusting for confounding, stabilization using ESF remained associated with a higher risk of complications (OR = 13.71 [CI: 2.18; 274.25], p = 0.02). Cats with ESF had a longer duration of follow-up (15.6 weeks; 95% CI: 13.0; 18.3) compared to ORIF (9.5 weeks; 95% CI: 6.4; 12.7) (p = 0.003), and a higher number of revisits (mean 3.0; 95% CI: 2.4; 3.6) than the ORIF group (mean 1.6; 95% CI: 0.9; 2.3) (p = 0.002). Clinical significance: This study demonstrates a significant difference in complication rates between the methods of stabilization, with ESF resulting in a significantly higher complication rate compared to ORIF. Based on these results, it may be prudent to select ORIF for stabilization of feline tibial fractures wherever practical.... K. L. Perry (1), M. Bruce (2) 23961 2015-02-04 14:50:50 Ahead of print: Risk factors for tibial tuberosity fracture after tibial tuberosity advancement in... Objective: To retrospectively identify factors that predispose to tibial tuberosity (TT) fracture after tibial tuberosity advancement (TTA) in dogs. Methods: The medical records and radiographs of a group of control dogs (n = 212) that had TTA surgery (n = 241 procedures) and did not sustain a fracture between 2008 and 2013, and those of 12 dogs that did sustain a fracture (n = 13 procedures) between 2008 and 2013 at two veterinary teaching hospitals were evaluated to determine the effect of signalment, body weight and surgical inaccuracies on TT fracture. Multivariable logistic regression was performed with the occurrence of TT fracture as the outcome variable of interest. Results: Signalment and body weight were not found to be associated with TT fracture. Of the surgical inaccuracies, osteotomy shape (p = 0.003), plate position (p = 0.009), and cage position (p = 0.039) were factors significantly associated with TT fracture. Clinical significance: This study provides data to support the hypothesis that poor plate position, poor cage position, and narrow distal osteotomy width are associated with TT fracture after TTA. We conclude that it is of paramount importance to pay careful attention to surgical technique in order to reduce this risk.... A. E. Nutt (1), P. Garcia-Fernandez (2), F. San Roman (2), T. Parkin (3), I. Calvo (1, 4) 23960 2015-02-04 14:49:38 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