Veterinary and Comparative Orthopaedics and Traumatology (VCOT) Veterinary and Comparative Orthopaedics and Traumatology (VCOT) vcot de-de Sun, 04 Dec 16 07:05:19 +0100 Farewell from the Publishers Geoffrey Sumner-Smith 1928-2016 D. Bergemann, A. Schürg, L. Lenz, E. Switzer 26897 2016-11-23 11:56:04 A Tribute to Professor Geoffrey Sumner-Smith 1928 – 2016 Kenneth A. Johnson 26896 2016-11-23 11:54:16 The interaction of working length and plate strain S. Roe (1) 26895 2016-11-23 11:42:20 Ahead of print: Traumatic fracture of the medial coronoid process in 24 dogs D. von Pfeil (1, 2), M. Albrecht (3), M. Glassman (1) 26869 2016-11-16 13:47:59 Ahead of print: Computed tomography and radio-graphic assessment of congruity between the ulnar... Objective: Assess the fit between the ulnar trochlear notch (UTN) and humeral trochlea (HT) in elbow radiographs and computed tomography (CT) images by measuring the curvature radii in normal joints. Methods: Mediolateral extended view (MLE) and CT were performed on 16 elbows from cadaveric dogs weighing over 20 kg. Curves were traced at the subchondral level from the UTN central ridge and the HT sagittal groove related to the UTN on ~132° joint extension. Curvature radii were achieved using appropriate computer software. Results: Intraclass correlation coefficient between MLE/CT measurements were statistically significant, with lower limits of a 95% confidence interval (CI) >0.75. The mean differences between MLE/CT measurements were -0.71 mm (95% CI: -0.97 to -0.45) for UTN and -1.04 mm (95% CI: -1.21 to -0.87) for HT. The UTN and HT curvature radii typology were similar, with maximum radius values at the starting point and two intermediate peaks. The UTN curvature radii were bigger than the HT radii, with the largest differences in the most proximal aspect of the joint and in the second intermediate peak. Clinical significance: To the authors’ knowledge, this is the first report on humeroulnar congruity through curvature radii evaluation. The software and methodology proposed enabled an adequate UTN and HT radii curvature assessment in MLE and CT images. Comparative studies in normal and dysplastic dogs of various breeds could better clarify the role of UTN and HT curvature radii in elbow incongruity and dysplasia.... S. Alves-Pimenta (1, 2), M. M. Ginja (2, 3), A. M. Fernandes (4), A. J. Ferreira (5), P. Melo-Pinto (2, 6), B. Colaço (1, 2) 26868 2016-11-16 13:47:00 Ahead of print: Revision of a BFX total hip replacement stem using a Kyon stem and a head adaptor in... Objective: To report revision of BFX cementless press-fit stem loosening with a Kyon cementless stem and a head adaptor in two dogs. Methods: Total hip arthroplasty stem revision was performed in two dogs with loosening of a previously implanted Biomedtrix press-fit BFX stem. Both dogs had a well-integrated BFX cup and single stage revision was performed using a standard Kyon stem and a head adaptor in order to couple with a 17 mm head and maintain the BFX cup. Results: Revisions resulted in a stable functional prosthesis with successful bone integration at the one-year postoperative re-evaluation. Conclusions: Use of a Kyon stem with a head adaptor may be a successful option to provide immediate stem stability for revision of a loosened BFX stem with a properly osseointegrated cup. L. Vezzoni (1), S. Bazzo (1), A. Vezzoni (1) 26867 2016-11-16 13:46:10 Ahead of print: Evaluation of the use of intra-operative radiology for open placement of lag screws... Objectives: To assess the effect of intra-operative radiology on the quality of lag screw insertion for the management of sacroiliac joint luxations in cats. Methods: In this retrospective single-centre study, the surgical, anaesthetic and imaging records of 40 screws (32 cats) placed with lag effect for management of sacroiliac luxation were reviewed. Postoperative radiographs were assessed for sacroiliac joint reduction, screw position, and sacral width purchased by each screw. Cases were divided into two groups according to the use of (IOR) or the absence of intra-operative radiology (NIOR). Results: A total of 23 lag screws were placed with the aid of intra-operative radiology and 17 without. Three of the 23 screws placed in the IOR group exited the sacrum as opposed to eight of 17 screws in the NIOR group (p = 0.03). Mean sacral width purchased by the screws in the IOR group (70.8%) was also significantly higher (p = 0.002) than in the NIOR group (54.6%). Mean general anaesthetic times for unilateral and bilateral screw placement for the IOR group and NIOR group were not significantly different. Clinical significance: The use of intra-operative radiology can significantly improve the quality of lag screw insertion for the stabilization of sacroiliac luxations in cats, which should lead to a reduced incidence of postoperative screw loosening.... F. Silveira (1), R. J. Quinn (1), A. M. Adrian (1), M. R. Owen (1), M. A. Bush (1) 26866 2016-11-16 13:45:00 Ahead of print: Sagittal accuracy of tibial osteotomy position during in vivo tibial plateau... Objectives: To assess the accuracy of tibial osteotomy location for tibial plateau levelling osteotomy (TPLO) in the sagittal plane and its effect on the postoperative tibial plateau angle (TPA), when performed without an alignment jig and saw guide. Also, to document the improvement gained with experience. Methods: Medical records and stifle radiographs of dogs undergoing TPLO, without the use of an alignment jig and saw guide, by one surgeon were reviewed (2010–2014). Postoperative radiographs were reviewed to record the distance and direction of eccentricity. Postoperative TPA was also recorded. Results: In a series of 401 TPLO procedures, 231 met the inclusion criteria. The absolute distance of eccentricity (DOE) for all dogs was 3.0 ± 1.6 mm. When evaluating surgical experience, the DOE for the final 77 cases (2.72 ± 1.43 mm), the middle 77 cases (3.18 ± 1.49 mm), and the first 77 cases (3.24 ± 1.7 mm) were not significantly different(p = 0.07157). There was a very weak correlation between DOE and postoperative TPA (R = 0.029). Clinical significance: The location of the tibial osteotomy when performing TPLO without an alignment jig and saw guide compared favourably with previously documented use of an alignment jig and saw guide. Whilst the location of the tibial osteotomy has a theoretical impact on the postoperative TPA, other factors appear to be of greater importance. Surgeon experience did not result in significant improvement in accuracy up to 231 procedures.... A. Craig (1), P. G. Witte (1), H. W. Scott (1) 26865 2016-11-16 13:44:03 Ahead of print: Influence of calcium salts and bovine thrombin on growth factor release from equine... Objective: To compare five activation methods in equine platelet-rich plasma (PRP) by determination of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-β1) concentrations in platelet-rich gel (PRG) supernatants. Methods: Platelet-rich plasma from 20 horses was activated by calcium chloride (CC), calcium gluconate (CG), bovine thrombin (BT), and their combinations, BTCC and BTCG. Both growth factor concentrations in PRG supernatants were measured by ELISA and compared with plasma and platelet lysates (PL) over time. Results: Growth factor concentrations were significantly lower in plasma and higher for all PRG supernatants. Platelet lysates contained a significantly lower concentration of PDGF-BB than PRG supernatants and a significantly higher concentration of TGF-β1 than PRG supernatants. Clots from PRP activated with sodium salts were more stable over time and had significant growth factor release, whereas CC produced gross salt deposition. Significant correlations were noticed for platelet with leukocyte concentrations in PRP (rs: 0.76), platelet counts in PRP with TGF-β1 concentrations in PRG supernatants (rs: 0.86), platelet counts in PRP with PDGF-BB concentrations in PRG supernatants (rs: 0.78), leukocyte counts in PRP with TGF-β1 concentrations in PRG supernatants (rs: 0.76), and PDGF-BB concentrations with activating substances (rs: 0.72). Clinical significance: Calcium gluconate was the better substance to induce PRP activation. It induced growth factor release free from calcium precipitates in the clots. Use of BT alone or combined with calcium salts was not advantageous for growth factor release.... C. E. Giraldo (1), M. E. Álvarez (1), J. U. Carmona (1) 26864 2016-11-16 13:43:03 Ahead of print: The evaluation of limb symmetry indices using ground reaction forces collected with... Objective: To compare the variability of symmetry indices within and between days when using one and two force plates for data collection. Animals: Seventeen healthy client-owned adult dogs. Methods: Vertical ground reaction force data were collected in a crossover study design, with four collection sessions on two consecutive days, and then two weeks apart (days 1, 2, 15, and 16) using both 1-plate and 2-plate collection methods. Symmetry indices were calculated for limb pairs using two standard equations (SI1 and SI2). Repeated measures analysis was used to compare symmetry indices data between plate systems and days. Significance was set at p N. J. Volstad (1), G. Sandberg (1), S. Robb (1), S. C. Budsberg (1) 26863 2016-11-16 13:42:03 Ahead of print: Kirschner wire fixation of Salter-Harris type IV fracture of the lateral aspect of... Objectives: To evaluate the use of Kirschner wires for treatment of fractures of the lateral aspect of the humeral condyle in growing dogs. Methods: Retrospective analysis of 35 elbow fractures (33 dogs) of the lateral aspect of the humeral condyle treated by insertion of multiple transcondylar and one anti-rotational Kirschner wires. Radiographic and clinical re-evaluations were carried out immediately after surgery, at four weeks and, when required, at eight weeks postoperatively. Long-term follow-up was planned after a minimum of six months. The relationship between different implant configurations and clinical outcome was analysed statistically. Results: Complete functional recovery was seen in 31 elbows (30 dogs), three elbows (2 dogs) had reduction in the range of motion, and one elbow (1 dog) had persistent grade 1 lameness two months postoperatively. Major complications occurred in eight elbows (8 dogs) and all were resolved by implant removal. Implant configuration did not affect outcome. Long-term evaluation in 12 cases with a mean follow-up of four years showed absence of lameness, normal function and no or mild radiographic evidence of osteoarthritis in 11 cases. Clinical significance: Fracture of the lateral aspect of the humeral condyle in growing dogs can be successfully treated by multiple transcondylar convergent or parallel Kirschner wires, resulting in adequate fracture healing.... F. Cinti (1, 2), G. Pisani (1), L. Vezzoni (2), B. Peirone (3), A. Vezzoni (2) 26862 2016-11-16 13:41:06 Ahead of print: Biomechanical comparison of two ostectomy configurations for partial mandibulectomy Objective: To determine the stiffness and load to failure of two different ostectomy configurations using canine mandibles. Study design: Cadaveric biomechanical assessment. Animals: Paired mandibles (n = 30). Methods: Standardized partial ostectomies were created on the alveolar surface of 30 mandibles. Samples were randomly assigned to right-angled (n = 15) or crescentic ostectomy (n = 15). Excision spanned the mesial aspect of the fourth premolar tooth to the distal aspect of first molar tooth. Mandibles were loaded to failure in three-point bending. The stiffness, displacement at maximum load, and load to failure were measured. Results: There was no significant difference in stiffness (p = 0.59), displacement at maximum load (p = 0.16) and load to failure (p = 0.76) between right-angled or crescentic ostectomy. Right-angled and crescentic ostectomy failed mostly by fracture through an empty alveolus (11/15 and 13/15, respectively). Clinical relevance: No significant differences in load to failure or stiffness between ostectomy techniques were observed. Crescentic ostectomy did not improve the acute load to failure for partial mandibulectomy. The empty alveolus served as a focal stress concentration point eliminating the potential mechanical advantage of a crescentic ostectomy.... D. Linden (1), B. M. Matz (1), R. Farag (1), H. W. Boothe (1), D. M. Tillson (1), R. Henderson (1) 26861 2016-11-16 13:39:49 Inter- and intra-observer variability of radiography and computed tomography for evaluation of... Objective: To evaluate the inter- and intra-observer variability in measurement of the angle of lateral opening (ALO) and version angle measurement using digital radiography and computed tomography (CT). Methods: Each hemipelvis was implanted with a cementless acetabular cup. Ventrodorsal and mediolateral radiographs were made of each pelvis, followed by CT imaging. After removal of the first cup, the pelves were implanted with an acetabular cup in the contralateral acetabulum and imaging was repeated. Three surgeons measured the ALO and version angles three times for each cup from the mediolateral radiographic projection. The same measurements were made using three-dimensional multiplanar reconstructions from CT images. Two anatomical axes were used to measure pelvic inclination in the sagittal plane, resulting in six measurements per cup. Two-way repeated measures analysis of variance evaluated inter- and intra-observer repeatability for radiographic and CT-based measurements. Results: Version angle based on radiographic measurement did not differ within surgeons (p = 0.433), but differed between surgeons (p... J. O. Leasure (1), J. N. Peck (1), A. Villamil (1), K. L. Fiore (1), C. A. Tano (1) 26741 2016-10-25 11:13:47 Effect of monocortical and bicortical screw numbers on the properties of a locking... Objectives: To evaluate the effect of varying the number and configuration of locking bicortical and monocortical screws on a plate-rod construct using a mid-diaphyseal femoral ostectomy model. Methods: Thirty Greyhound femurs were assigned to six groups (A-F). An intramedullary pin was placed in each bone following which a 3.5 mm locking plate was applied with six differing locking screw configurations. Groups A to C had one bicortical screw in the most proximal and distal plate holes and one to three monocortical locking screws in the proximal and distal fragments. Groups D to F had no bicortical screws placed and two to four monocortical locking screws in proximal and distal fragments. Each construct was axially loaded at 4 Hz from a preload of 10 Newtons (N) to 72 N, increasing to 144 N and 216 N, each of 6000 cycles with a further 45,000 cycles at 216 N to simulate a three to six week postoperative convalescence period. Constructs were then loaded to failure. Results: No construct suffered screw loosening or a significant change in construct stiffness during cyclic loading. There was no significant difference in load to failure of any construct (p = 0.34), however, less variation was seen with monocortical constructs. All constructs failed at greater than 2.5 times physiological load, and failure was by bending of the intramedullary pin and plate rather than screw loosening or pull-out. Clinical significance: Axially loaded locking monocortical plate-rod constructs applied to the canine femur may confer no difference biomechanically to those employing locking bicortical screws.... E. J. Field (1), K. Parsons (1), J. A. Etches (2), K. Hamilton (3), N. J. Burton (1) 26740 2016-10-25 11:11:31 One-stage revision of an infected cementless total hip replacement A two-year-old, 44 kg dog with a right Helica cementless total hip replacement (THR) was radiographically diagnosed with implant loosening eight months after the index total hip replacement procedure. Subsequent synoviocentesis and synovial fluid culture revealed a methicillin-resistant coagulase-negative Staphylococcus spp infection of the right THR. A one-stage revision using a hybrid BFX cementless acetabular cup and CFX cemented femoral stem was performed. Vancomycin and micro-silver antimicrobial powder impregnated cement were used in the revision. At re-evaluation 27 months following the revision procedure, the patient did not exhibit any signs of lameness. Radiographic images confirmed stable implants, with bone ingrowth into the cup and no signs of implant loosening. Our report demonstrates the success of a one-stage THR revision when faced with a multi-drug resistant periprosthetic infection, when combined with the use of micro-silver antimicrobial powder and culture-based antibiotic impregnated cement therapy.... M. G. Ficklin (1), M. P. Kowaleski (2), K. A. R. Kunkel (1), J. T. Suber (1) 26725 2016-10-20 10:11:52 Evaluation of inertial measurement units as a novel method for kinematic gait evaluation in dogs Objective: To evaluate the use of inertial measurement units (IMU) for quantification of canine limb kinematics. Methods: Sixteen clinically healthy, medium-sized dogs were enrolled. Baseline kinematic data were acquired using an optical motion capture system. Following this baseline data acquisition, a harness system was used for attachment of IMU to the animals. Optical kinematic data of dogs with and without the harness were compared to evaluate the influence of the harness on gait parameters. Sagittal plane joint kinematics acquired simultaneously with IMU and the optical system were compared for the carpal, tarsal, stifle and hip joints. Comparisons of data were made using the concordance correlation coefficient (CCC) test and evaluation of root mean squared errors (RMSE). Results: No significant differences were demonstrated in stance duration, swing duration or stride length between dogs instrumented with or without the harness, however, mean RMSE values ranged from 4.90° to 14.10° across the various joints. When comparing simultaneously acquired optical and IMU kinematic data, strong correlations were found for all four joints evaluated (CCC: carpus = 0.98, hock = 0.95, stifle = 0.98, hip = 0.96) and median RMSE values were similar across the joints ranging from 2.51° to 3.52°. Conclusions and Clinical relevance: Canine sagittal plane motion data acquisition with IMU is feasible, and optically acquired and IMU acquired sagittal plane kinematics had good correlation. This technology allows data acquisition outside the gait laboratory and may provide an alternative to optical kinematic gait analysis for the carpal, tarsal, stifle, and hip joints in the dog. Further investigation into this technology is indicated.... F. M. Duerr (1), A. Pauls (1), C. Kawcak (2), K. Haussler (2), G. Bertocci (3), V. Moorman (2), M. King (2) 26724 2016-10-20 10:06:05 Evaluation of an overlapping pubic and ischiatic osteotomy for the improvement of acetabular... Objectives: To assess the potential of a new single-session surgical procedure, the overlapping pubic and ischiatic osteotomy (OPIO) for modification of bilateral hip conformation. We hypothesized that OPIO would be simple to perform with currently available surgical equipment, through a single surgical approach, with minimal potential morbidity, and that it would allow adequate simultaneous bilateral improvement of coxofemoral joint conformation in patients at risk of canine hip dysplasia. Methods: The OPIO procedure was performed in the pelves of five large breed canine cadavers. Computed tomography images of each cadaver were compared by measurement of the dorsal acetabular rim angle (DARA), acetabular angle (AA), dorso-ventral sacroiliac ratio (SR), and pubic inlet area before and after OPIO. Results: Coxofemoral joint conformation was improved after OPIO. Postoperative DARA was significantly decreased (mean: –5.09°) and AA was significantly increased (mean: 3.54°) after OPIO. The SR was not significantly different after OPIO, indicating minimal impact on the sacro-illiac joints by the procedure. Pubic inlet dimensions and area were significantly decreased after OPIO, but the overall effect on pelvic inlet area was clinically insignificant. Clinical significance: An OPIO allows some improvement of coxofemoral joint conformation in canine cadavers.... J. A. Gervais (1), J. K. Roush (1), D. S. Biller (1) 26723 2016-10-20 10:05:13 Combined tibial plateau levelling osteotomy and tibial tuberosity transposition for treatment of... Objectives: To describe the surgical technique and report short-term outcome for combined tibial plateau levelling osteotomy and tibial tuberosity transposition (TPLO-TTT) as an option in the treatment of cranial cruciate ligament insufficiency with concomitant medial patellar luxation. Methods: Medical records were reviewed (2011–2013) of dogs that underwent a standard tibial plateau levelling osteotomy followed by a tibial tuberosity transposition in the frontal plane and stabilized with pin and tension-band wire fixation as a component of surgical treatment for combined cranial cruciate ligament insufficiency and medial patellar luxation. Signalment, fixation method together with any ancillary procedures, function at the in-hospital follow-up examinations, and any complications were recorded. Healing was assessed retrospectively based on the grading criteria of the International Society Of Limb Salvage. Results: Fifteen stifle joints in 11 dogs were identified; 13 stifles were available for in-hospital follow-up. All 13 achieved union (3 with grade III/IV and 10 with grade IV/IV radiographic healing scores); mean time to healing was 10.6 (± 2.9) weeks. Patellar ligament thickening was also identified radiographically in seven of the 13 of stifle joints. All dogs were reported to have mild or no lameness at their last follow-up examination. No catastrophic or major postoperative complications occurred that required additional surgery. Patellar re-luxation did not occur in any of the 13 stifles available for in-hospital follow-up. Clinical significance: The TPLO-TTT was found to be a reliable and effective technique when used as a part of the treatment of combined cranial cruciate ligament insufficiency with concomitant medial patellar luxation in this series of dogs.... K. C. Leonard (1), M. P. Kowaleski (1), W. B. Saunders (2), R. J. McCarthy (1), R. J. Boudrieau (1) 26694 2016-10-14 11:26:16 Clinical evaluation of a mini locking plate system for fracture repair of the radius and ulna in... Objectives: To retrospectively evaluate the effectiveness of a novel 1.2 mm mini locking plate system in treating fractures of the radius and ulna in miniature breed dogs. Methods: Medical records and radiographs of miniature breed dogs with fractures treated with a 1.2 mm mini locking plate system were reviewed. The inclusion criteria were: body weight of 2.5 kg or less, transverse or short oblique fracture of the radius and ulna, and treatment with a mini locking plate system as the sole method of fixation. For each patient, data including signalment, time to radiographic union, use of bone graft or other agents, and previous repair attempts were recorded. The outcome and complications were determined from clinical and radiographic follow-up examinations. Results: Fourteen cases with a mean radial width of 4.5 mm (± 0.8 mm) were included into this study. The fractures healed without failure of fixation in all cases. Mean time to adequate radiographic union was 8.4 weeks (± 2.6 weeks). Major complications were not seen in any of the cases, and minor complications occurred in three of the cases. Limb function was graded as ‘normal’ in 10 cases and ‘occasional lameness’ in four cases. Clinical significance: The mini locking system evaluated in this study was an effective treatment method for radial and ulnar fractures in miniature breed dogs with a radial width smaller than 5.5 mm.... B.-J. Kang (1), H.-H. Ryu (2), S. Park (3), Y. Kim (4), O.-K. Kweon (4), K. Hayashi (5) 26693 2016-10-14 11:23:20 Evaluation of the relationship of tibiofemoral kinematics before and after total knee replacement in... Objective: To investigate the relationship between tibiofemoral kinematics before and after total knee replacement (TKR) in vitro. Animals: Eight canine hemipelves. Methods: A modified Oxford Knee Rig was used to place cadaveric limbs through a range of passive motion allowing the kinematics of the stifle to be evaluated. Four measurements were performed: a control stage, followed by a cranial cruciate transection stage, then following TKR with the musculature intact stage, and finally TKR with removal of limb musculature stage. Joint angles and translations of the femur relative to the tibia, including flexion-extension versus adduction-abduction, flexion-extension versus internal-external rotation, as well as flexion-extension versus each translation (cranial-caudal and lateral-medial) were calculated. Results: Significant differences were identified in kinematic data from limbs following TKR implantation as compared to the unaltered stifle. The TKR resulted in significant decreases in external rotation of the stifle during flexion-extension compared to the limb prior to any intervention, as well as increasing the abduction. The TKR significantly increased the caudal translation of the femur relative to the tibia compared to the unaltered limb. When compared with the cranial cruciate ligament-transection stage, TKR significantly decreased the ratio of the external rotation to flexion. Discussion: All three test periods showed significant differences from the unaltered stifle. The TKR did not completely restore the normal kinematics of the stifle.... R. N. Howie (1), T. L. Foutz (1), C. C. Cathcart (2), J. S. Burmeister (3), S. C. Budsberg (2) 26692 2016-10-14 11:22:43 Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy... Objectives: To describe clinical, radiographic, and magnetic resonance imaging (MRI) findings in 16 dogs diagnosed with gastrocnemius musculotendinopathy. Methods: Retrospective evaluation of medical records, radiographs, and MRI results, as well as follow-up completed by telephone questionnaire. Results: Most dogs had chronic hindlimb lameness with no history of trauma or athletic activities. Clinical examination revealed signs of pain on palpation without stifle joint instability. Seven dogs had radiographic signs of osteophyte formation on the lateral fabella. Magnetic resonance imaging revealed T2 hyperintensity and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. Changes were found in the lateral and medial heads of the gastrocnemius. Conservative treatment resulted in return to full function in 11 dogs. Two dogs showed partial restoration of normal function, one dog showed no improvement. Two dogs were lost to follow-up. Clinical significance: Gastrocnemius musculotendinopathy is a potential cause of chronic hindlimb lameness in medium to large breed dogs. A history of athletic activity must not necessarily be present. Magnetic resonance imaging shows signal changes and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. A combination of T1 pre- and post-contrast administration and T2 weighted sequences completed by a fat-suppressed sequence in the sagittal plane are well-suited for diagnosis. Conservative treatment generally results in return to normal function.... S. M. Kaiser (1), O. Harms (2, 3), M. Konar (4), A. Staudacher (1), A. Langer (3), C. Thiel (1), M. Kramer (1), S. Schaub (1), K. H. von Pückler (1) 26691 2016-10-14 11:21:28 Evaluation of an intra-articular synthetic ligament for treatment of cranial cruciate ligament... Objective: Evaluate the short-term outcomes of a novel synthetic ligament for treatment of naturally occurring canine cranial cruciate ligament disease. Study design: Prospective clinical study. Animals: Dogs with unilateral cranial cruciate ligament disease (n = 50). Methods: Patient parameters evaluated included a five-point lameness score, evaluation of craniocaudal stifle instability, and radiographic findings over 24 weeks. Any postoperative complications were recorded. Results: Thirty-four out of 42 dogs experienced significant improvements in lameness between the preoperative and 24 week time points. Lameness scores in those dogs improved significantly at all measured time intervals after postoperative week 2. Recurrence of stifle instability increased significantly over the study period from immediate postoperative measurements. Cranial drawer recurred in seven out of 42 of dogs by week 4 and 18/42 by week 24. Implant changes were not noted between the immediate and six-month postoperative radiographs except where complications occurred. Overall, 25 dogs experienced a total of 32 complications (22 major and 10 minor). Sixteen dogs had major complications, and nine had minor complications. Conclusion: The procedure was generally effective at improving lameness scores, but did not consistently maintain postoperative stifle stability and had an unacceptably high complication rate. This synthetic ligament procedure cannot be recommended for use in its current form.... M. D. Barnhart (1), K. Maritato (2), K. Schankereli (3), H. Wotton (4), S. Naber (5) 26665 2016-10-06 09:10:41 Tibial plateau levelling osteotomy in eleven cats with cranial cruciate ligament rupture Objective: To report the surgical procedure, intra- and postoperative complications, and short-term follow-up of tibial plateau levelling osteotomy (TPLO) in feline patients with cranial cruciate ligament (CrCL) rupture using a 2.0 or 2.4 mm Synthes® TPLO plate. Study design: Prospective study. Material and methods: Eleven cats with a CrCL rupture were included in the study. Inspection of intra-articular structures was carried out via arthroscopy or arthrotomy. Each patient was re-examined one and 10 days after surgery. Orthopaedic examination and follow-up radiographs were obtained four to 12 weeks postoperatively. Results: Two meniscopathies and one partial CrCL rupture were detected. Minor intra-operative complications occurred in five cats (suboptimal positioning of the plate [n = 3], proximal fibular fracture [n = 1], a visible osteotomy gap [n = 1]). Postoperatively, minor complications were detected in three cats (mild patellar desmitis [n = 2], superficial wound infection [n = 1]). No additional surgical reintervention, graded as major complication, was necessary. Four to eight weeks postoperatively, all cats showed no to mild intermittent lameness. Complete bone union was apparent within four to 12 weeks. Owners reported a high level of comfort and mobility during the last follow-up. Conclusion: The preliminary results of this study support the use of TPLO in cats, but larger case numbers are needed to evaluate its practicability, as well as long-term outcome (>1 year), especially evaluating the development and the clinical relevance of osteoarthritis.... J. K. Mindner (1), M. J. Bielecki (1), S. Scharvogel (1), D. Meiler (1) 26664 2016-10-06 09:09:50 Pullout strength of monocortical and bicortical screws in metaphyseal and diaphyseal regions of the... Objective: Monocortical screws are commonly employed in locking plate fixation, but specific recommendations for their placement are lacking and use of short monocortical screws in metaphyseal bone may be contraindicated. Objectives of this study were to evaluate axial pullout strength of two different lengths of monocortical screws placed in various regions of the canine humerus compared to bicortical screws, and to derive cortical thickness and bone density values for those regions using quantitative computed tomography analysis (QCT). Methods: The QCT analysis was performed on 36 cadaveric canine humeri for six regions of interest (ROI). A bicortical, short monocortical, or 50% transcortical 3.5 mm screw was implanted in each ROI and axial pullout testing was performed. Results: Bicortical screws were stronger than monocortical screws in all ROI except the lateral epicondylar crest. Short monocortical metaphyseal screws were weaker than those placed in other regions. The 50% transcortical screws were stronger than the short monocortical screws in the condyle. A linear relationship between screw length and pullout strength was observed. Clinical significance: Cortical thickness and bone density measurements were obtained from multiple regions of the canine humerus using QCT. Use of short monocortical screws may contribute to failure of locking plate fixation of humeral fractures, especially when placed in the condyle. When bicortical screw placement is not possible, maximizing monocortical screw length may optimize fixation stability for distal humeral fractures.... D. P. Vaughn (1), J. A. Syrcle (1), J. E. Ball (2), S. H. Elder (3), J. M. Gambino (1), R. L. Griffin (4), R. M. McLaughlin (1) 26663 2016-10-06 09:09:00 The effect of intramedullary pin size and plate working length on plate strain in locking... Objective: To investigate the effect of intramedullary pin size and plate working length on plate strain in 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. Two screws per fragment modelled a long (8-hole) and short (4-hole) plate working length. Strain responses to axial compression were recorded at six regions of the plate via three-dimensional digital image correlation. Results: The addition of a pin of any size provided a significant decrease in plate strain. For the long working length, LCPR-30 and LCPR-40 had significantly lower strain than the LCPR-20, and plate strain was significantly higher adjacent to the screw closest to the fracture site. For the short working length, there was no significant difference in strain across any LCPR constructs or at any region of the plate. Plate strain was significantly lower for the short working length compared to the long working length for the LCP-Mono and LCPR-20 constructs, but not for the LCPR-30 and LCPR-40 constructs. Clinical significance: The increase in plate strain encountered with a long working length can be overcome by the use of a pin of 30–40% intramedullary diameter. Where placement of a large diameter pin is not possible, screws should be placed as close to the fracture gap as possible to minimize plate strain and distribute it more evenly over the plate.... T. Pearson (1), M. R. Glyde (1), R. E. Day (2), G. L. Hosgood (1) 26662 2016-10-06 09:08:14