Veterinary and Comparative Orthopaedics and Traumatology (VCOT) Veterinary and Comparative Orthopaedics and Traumatology (VCOT) vcot de-de Fri, 28 Aug 15 16:43:42 +0200 Ahead of print: Surgical correction of a bilateral congenital tarsal hyperextension deformity in a... Case description: An approximately three-month-old, 0.45 kg female Domestic Shorthaired kitten with stiff hyperextended hindlimbs distal to the talo-central joint is reported. Attempts at repositioning of the joints by flexion failed while increased manipulative forces caused signs of pain and vocalization. Orthogonal radiographic views revealed a significant malarticulation of the tarsus. Goniometric measurments revealed a 145° extensor and 95° internal torsional deformity. Treatment and outcome: Pantarsal arthrodesis with a transarticular external fixation system was performed for both limbs in two separate stages. Pre-assembled frames were composed of two 40 mm diameter half rings (on the medial side) and two 40 mm diameter full rings connected with two pre-contoured (125° flexion) rods from proximal to distal. Following transection of the superficial and deep digital flexor tendons, cartilage was removed from the articular surfaces, autologous cancellous bone graft was inserted, and joints were fixed in 125° flexion with pre-contured external frames. The cat commenced weight-bearing bilaterally immediately postoperatively. Frames were removed 32 and 27 days after application. Two months after frame removal, joint fusion was confirmed and full weight-bearing at the walk and run was achieved. Clinical relevance: To our knowledge, this is the first report of surgical correction of a bilateral congenital tarsal hyperextension deformity by pantarsal arthrodesis using a transarticular external fixation system.... C. Yardımcı (1), A. Ozak (1), H. Özlem Nisbet (1) 24781 2015-08-24 13:54:00 Ahead of print: Unicameral bone cyst of the patella in a young dog This report describes a case of a solitary unicameral patellar bone cyst in a young dog. A five-month-old, male Dobermann Pinscher dog was referred for a 10-day left hindlimb lameness. A mild swelling of the peripatellar soft tissues of the left patella was detected upon physical examination. Signs of pain were elicited upon direct palpation of the patella. Radiographic examination revealed an oval radiolucency within the medullary cavity at the base of the left patella. Radiographic examination, arthroscopy, and histopathology findings supported the diagnosis of a benign patellar bone cyst. The condition was treated by surgical curettage and autogenous bone graft harvested from the ipsilateral proximal tibia. Clinical signs, including lameness and signs of pain upon deep palpation, disappeared three weeks after surgery. Follow-up re-evaluation five years after surgery revealed no recurrence of the cyst and the patient was asymptomatic. M. Petazzoni (1), F. Briotti (2), B. Beale (3) 24780 2015-08-24 13:38:52 Ahead of print: The equine forelimb suspensory ligament exhibits a heterogeneous strain pattern... Objectives: To determine if regional variations in strain patterns occur within the suspensory ligament under tensile load. Local increases in strain may put certain regions of the suspensory ligament at risk and may explain the poor healing and high recurrence rates associated with suspensory branch injuries. Methods: The suspensory ligament and its bone attachments were isolated from each of 10 adult equine cadaveric forelimbs and radiodense reference beads were inserted throughout the length of the ligament. Specimens were attached to a custom fixture secured to a materials testing system. Radiographs were acquired at 50, 445, 1112, and 2224 N of applied tensile load. Changes in distances between the beads in each region of the suspensory ligament were measured and the regional strain was calculated. Significant differences were determined using a repeated-measures analysis of variance. Results: The suspensory ligament exhibited significant differences in regional strain (p  M. Lavagnino (1), J. Madison (1), M. R. Williams (1), S. P. Arnoczky (1) 24661 2015-07-29 13:54:22 Ahead of print: Variability of vertical ground reaction forces collected with one and two force... Objective: To compare peak vertical force (PVF) and vertical impulse (VI) data collected with one and two force plates during the same collection time period in healthy dogs at a trot. Animals: Seventeen healthy client-owned adult dogs. Methods: Vertical ground reaction force (GRF) data were collected in a crossover study design, with four sessions on two consecutive days, and then two weeks apart (days 1, 2, 15, and 16) using both one and two force plates collection methods. A repeated measures model analysis of variance (ANOVA) was used to test for differences in force plate PVF, VI, and average time per trial (ATT) between days, weeks, and systems (1 plate versus 2 plates). Coefficients of variation for PVF and VI were also calculated separately by forelimbs and hindlimbs, plates, day, and week. Results: The time required to obtain a valid trial was significantly longer using a single force plate when compared with two force plates. Comparing GRF data for all dogs, significant differences in PVF data were found between one and two force plates, however, these differences were diminutive in absolute magnitude, and of unknown clinical importance. Examination of the coefficients of variation for PVF and VI during the different collection periods yielded similar results. Conclusions: Use of two force plates decreased trial repetition and collection time. Vertical GRF data had a similar coefficient of variation with either one or two force plates collection techniques in healthy dogs.... M. Stejskal (1), B. T. Torres (1), G. S. Sandberg (1), J. A. Sapora (1), R. K. Dover (1), S. C. Budsberg (1) 24660 2015-07-29 13:52:49 Ahead of print: The use of low doses of acepromazine as an aid for lameness diagnosis in horses: An... Objectives: The aim of the present study was to quantify by accelerometry the trotting pattern of adult horses sedated with two different doses of acepromazine, in order to assess the use of this drug in equine lameness evaluations. Methods: Seven mature horses were used and three treatments were administered to each horse: saline solution, acepromazine (0.01 mg/kg), and acepromazine (0.02 mg/kg). The portable gait analyzer used consisted of three orthogonal accelerometers that measure accelerations along the dorsoventral, longitudinal, and lateral axes. Baseline values were obtained and after treatment, accelerometric recordings were repeated every five minutes during the first 20 minutes after the injection and then every 10 minutes thereafter for two hours. Ground-to-lip distance was also measured. Results: Administration of acepromazine decreased some of the variables investigated and differences between doses were observed. Speed, stride frequency, and stride length were significantly reduced following treatments. For coordination parameters, no significant differences among values were observed. Energetic variables suffered only weak reductions whereas ground-to-lip distance values were significantly decreased up to 120 minutes after treatment. Clinical significance: Acepromazine produces significant alterations in the gait pattern with differences between doses, but it does not affect coordination variables in normal unexcited horses, and at a dose of 0.01 mg/kg may be the tranquilizer of choice for evaluating lameness in this setting.... F. J. López-Sanromán (1), D. Gómez Cisneros (1, 2), M. Varela del Arco (1), I. Santiago Llorente (1), M. Santos González (3) 24659 2015-07-29 13:51:32 Ahead of print: Biomechanical comparison of two locking plate constructs under cyclic torsional... Objectives: The number of locking screws required per fragment during bridging osteosynthesis in the dog has not been determined. The purpose of this study was to assess the survival of two constructs, with either two or three screws per fragment, under cyclic torsion. Methods: Ten-hole 3.5 mm stainless steel locking compression plates (LCP) were fixed 1 mm away from bone surrogates with a fracture gap of 47 mm using two bicortical locking screws (10 constructs) or three bicortical locking screws (10 constructs) per fragment, placed at the extremities of each LCP. Constructs were tested in cyclic torsion (range: 0 to +0.218 rad) until failure. Results: The 3-screws constructs (29.65 ± 1.89 N.m/rad) were stiffer than the 2-screws constructs (23.73 ± 0.87 N.m/rad), and therefore, were subjected to a greater torque during cycling (6.05 ± 1.33 N.m and 4.88 ± 1.14 N.m respectively). The 3-screws constructs sustained a significantly greater number of cycles (20,700 ± 5,735 cycles) than the 2-screws constructs (15,600 ± 5,272 cycles). In most constructs, failure was due to screw damage at the junction of the shaft and head. The remaining constructs failed because of screw head unlocking, sometimes due to incomplete seating of the screw head prior to testing. Clinical significance: Omitting the third innermost locking screw during bridging osteosynthesis led to a reduction in fatigue life of 25% and construct stiffness by 20%. Fracture of the screws is believed to occur sequentially, starting with the innermost screw that initially shields the other screws.... A. Bilmont (1), S. Palierne (1), M. Verset (1), P. Swider (2), A. Autefage (1) 24658 2015-07-29 13:50:24 Ahead of print: Complications and outcome of a new modified Maquet technique for treatment of... Objectives: To describe the complications, short and long-term outcome and owner satisfaction of dogs with cranial cruciate ligament rupture treated with a recently described new osteotomy for the modified Maquet technique (N-MMT). Materials and methods: Medical records and radiographs of 82 dogs (84 stifles) were reviewed. Details regarding short-term outcome and complications were recorded from the medical records. Long-term follow-up information was obtained by telephone interview. Historical data and complications were statistically analysed. Results: Major complications occurred in 34/84 stifles. Intra-operative complications occurred in 26/84 stifles, all of which were fissures or fractures of the cortical hinge. Twenty-one of these fractures or fissures were repaired with a figure-of-eight wire. The second most common major complication was late meniscal tears in 3/84 stifles. One dog sustained a complete tibial fracture. Non-displaced fracture of the cortical hinge was the most common postoperative minor complication, which occurred in 5/84 stifles. The median preoperative lameness score was 3 out of 6. Final in-hospital re-evaluation of limb function was available in 58 dogs. The median lameness score at that time was 0 out of 6. Development of osteotomy related complications was not associated with a significant change in the postoperative lameness score. Clinical significance: Subjectively assessed clinical outcome with the N-MMT was good to excellent in this cohort of dogs. However, a high rate of intra- and postoperative complications of the N-MMT procedure was also present in these dogs.... J. Ramirez (1), N. Barthélémy (2), S. Noël (2), S. Claeys (2), S. Etchepareborde (3), F. Farnir (4), M. Balligand (2) 24657 2015-07-29 13:47:27 Ahead of print: Use of computed tomography to compare two femoral head and neck excision ostectomy... Objectives: To compare the results of femoral head and neck excision (FHNE) ostectomy performed by two novice veterinarians using an osteotome and mallet or microsagittal saw. Methods: In this ex vivo cadaveric study, hindlimbs of eight canine cadavers were randomized to FHNE with osteotome or micro sagittal saw as performed by two recently graduated veterinarians. The hindimbs were imaged by computed tomography (CT) before and after the osteotomy. Post FHNE CT images were evaluated by a board certified radiologist blinded to the ostectomy technique for assessment of the number of bone fragments, fissures, smoothness of osteotomy margination, and volume of residual femoral neck. Results: Femoral head and neck excision performed with the osteotome produced more peri-ostectomy bone fragments, cortical fissures, irregular margins, and residual femoral neck volume, compared with osteotomy using a saw. Clinical relevance: Compared to FHNE performed with a sagittal saw, osteotome FHNE resulted in a greater bone trauma and residual neck bone volume, which would require post-ostectomy modification in a clinical setting.... M. D. O'Donnell (1, 2), J. J. Warnock (1), G. Bobe (3), R. P. Scholz (1, 4), J. E. Wiest (1), S. Nemanic (1) 24628 2015-07-21 08:36:02 Ahead of print: Biomechanical properties of the atlantoaxial joint with naturally-occurring... The biomechanical properties of the atlanto-axial joint in a young Yorkshire Terrier dog with spontaneous atlantoaxial instability were compared to those of another young toy breed dog with a healthy atlantoaxial joint. The range-of-motion was increased in flexion and lateral bending in the unstable joint. In addition, lateral bending led to torsion and dorsal dislocation of the axis within the atlas. On gross examination, the dens ligaments were absent and a longitudinal tear of the tectorial membrane was observed. These findings suggest that both ventral and lateral flexion may lead to severe spinal cord compression, and that the tectorial membrane may play a protective role in some cases of atlantoaxial instability. F. Forterre (1), C. Precht (2), B. Riedinger (1), A. Bürki (3) 24627 2015-07-21 08:35:04 Ahead of print: Tibial anatomy in normal small breed dogs including anisometry of various... Objectives: To investigate proximal tibial anatomy and its influence on anisometry of extracapsular stabilizing sutures in small dog breeds. Materials and methods: Mediolateral radiographs of the femora, stifles, and tibiae of 12 small breed dogs were acquired with the stifles positioned at various angles. Measurements taken included tibial plateau angle (TPA), diaphyseal: proximal tibial angle (DPA), patellar tendon angle (PTA), Z-angle, relative tibial tuberosity width (rTTW), and the distance between six combinations of two femoral and three tibial ECS attachment sites. Theoretical strain through stifle range-of-motion was recorded. Results: The TPA (32° ± 5.8°), DPA (10.2° ± 7.3°), PTA (103.7° ± 6.2°), and Z-angle (70.4° ± 9.0°) were positively correlated with one another (R >0.7), but none were correlated with rTTW (0.93 ±0.10). The F2-T1 combination of ECS attachment sites had lowest strain for nine stifles. The shortest attachment site separation was at a stifle flexion of 50° for nine stifles. Proximal tibial anatomy measurements could not predict optimal attachment site combination, optimal stifle angle for suture placement, or ECS strain. Clinical significance: There is individual variation in the optimal attachment site combination and stifle angle for suture placement, which may influence consistency of outcomes with ECS.... P. G. Witte (1) 24626 2015-07-21 08:31:52 Ahead of print: Analysis of lactate concentrations in canine synovial fluid Objective: To report synovial fluid lactate concentrations in normal and pathological canine joints. Study design: Controlled, prospective study. Methods: Lactate was measured in synovial fluid using a hand-held meter and the rest of the fluid was sent to a commercial laboratory for analysis. Samples were divided into four groups; group 1: control, group 2: osteoarthritis, group 3: immune-mediated inflammatory arthritis, and group 4: septic arthritis. Statistical analysis was performed to compare lactate concentrations between the four groups and to examine the predictive value of lactate in the diagnosis of septic arthritis. A correlation was sought between synovial fluid lactate and synovial fluid total nucleated cell count and total protein. Results: Seventy-four samples were investigated from 55 dogs. Statistical analysis found that lactate concentrations were significantly higher in the septic arthritis group than in each of the other three groups. No significant correlation could be found between synovial fluid lactate concentrations and synovial fluid total nucleated cell count or synovial fluid total protein. Lactate concentration was found to be a useful predictor of septic arthritis with a low concentration pointing towards exclusion rather than a high concentration to the diagnosis of septic arthritis. Clinical significance: Synovial fluid lactate concentration is not a good marker for osteoarthritis or immune-mediated inflammatory arthritis but it is significantly increased in septic arthritis and could help the clinician in ruling out this condition in a quick and cost-effective way.... J. L. J. Proot (1), F. de Vicente (1), D. E. Sheahan (1) 24472 2015-06-10 11:44:13 Influence of two types of self-retaining retractors on multifidus muscle blood flow during... Objectives: To assess the influence of the use of Gelpi and Grevel retractors on multifidus muscle blood flow during hemilaminectomy, using a dorsolateral approach, for acute disc extrusion in dogs as measured by laser speckle contrast imaging (LSCI). Methods: Blood flow in the multifidus muscles was measured intra-operatively using LSCI prior to insertion of the retractors, immediately after hemilaminectomy and removal of the retractors, and after 10 minutes of lavage of the surgical site. Plasma creatine kinase levels were measured preoperatively and 12–24 hours postoperatively. Results: Muscular blood flow was significantly decreased following retraction and remained lower than initial values 10 minutes after lavage in all dogs. The decrease in blood flow was significantly greater with Gelpi retractors (n = 8) than with Grevel retractors (n = 10). No significant relation was found between the duration of retraction and postoperative changes in creatine kinase levels or blood flow. Clinical significance: Findings in this study demonstrate a drop in blood flow within the multifidus muscles using the dorsolateral approach regardless of retractor type used. Gelpi retractors seem to have greater influence on muscular blood flow than Grevel retractors. Further studies are warranted to confirm this second finding.... D. Rohner (1), S. Forterre (1), H. Rohrbach (2), A. Bürki (3), D. Gorgas (4), J. Howard (5), F. Forterre (1) 24471 2015-06-10 11:43:19 Stifle arthrodesis using a locking plate system in six dogs Objectives: To describe the use of the Fixin locking plate system for stifle arthrodesis in dogs and to retrospectively report the clinical and radiographic outcomes in six cases. Materials and methods: Medical records of dogs that had arthrodesis with the Fixin locking plate system were reviewed. For each patient, data pertaining to signalment and implant used were recorded. Plate series and thickness, number of screws placed, number of cortices engaged, and screw diameters were also recorded. The outcome was determined from clinical and radiographic follow-ups. Radiographic outcomes assessed included the measurement of the postoperative femoral-tibial angle in the sagittal plane. Results: Six dogs met the inclusion criteria for the study. Mean body weight was 13 kg (range: 3 - 34 kg). Radiographic follow-up (mean: 32 weeks, range: 3 - 52 weeks) was available for all dogs. In one case, an intra-operative complication occurred. In another case, a tibial fracture occurred 20 days after surgery. All arthrodeses healed and no implant complication was detected although all cases had mechanical lameness. Clinical significance: Stifle arthrodesis can be performed successfully using a Fixin locking plate system.... M. Petazzoni (1), T. Nicetto (2) 24470 2015-06-10 11:42:15 Proximo-distal patellar position in three small dog breeds with medial patellar luxation Introduction: Medial patellar luxation is thought to be associated with a high proximal position of the patella in the trochlear groove. Objective: To determine whether the ratio of patellar ligament length and patellar length (L:P) is influenced by the stifle angle (75°, 96°, 113°, 130°, and 148°) in small dog breeds and to compare the L:P ratio in dogs of three small dog breeds with and without medial patellar luxation. Methods: A mediolateral radiograph of the stifle joint was used to measure the L:P ratio in the stifle joints of dogs of three small breeds with and without medial patellar luxation. The L:P ratio was evaluated at five stifle angles (75°, 96°, 113°, 130°, and 148°) in 14 cadavers (26 stifle joints) of small dog breeds in order to identify the best stifle angle to measure the L:P ratio. Then the mean ± SD L:P ratio was calculated for normal stifles and stifles with medial patellar luxation grades 1, 2, and 3 in 194 Pomeranians, 74 Chihuahuas, and 41 Toy or Standard Poodles. Results: The L:P ratio was the same for all five stifle angles in the cadavers (p = 0.195). It was also not significantly different in the three breeds (p = 0.135), in normal and medial patellar luxation-affected stifles overall (p = 0.354), and in normal and medial patellar luxation-affected joints within each breed (p = 0.19). Clinical significance: We conclude that a proximo-distal patellar position is not associated with medial patellar luxation in Pomeranians, Chihuahuas, and Toy or Standard Poodles. Thus a longer patellar ligament length does not play a role in the pathophysiology of medial patellar luxation in these small dog breeds.... C. Wangdee (1), L. F. H. Theyse (2), H. A. W. Hazewinkel (3) 24446 2015-06-03 13:15:22 Ex vivo biomechanical comparison of barbed suture and standard polypropylene suture for acute tendon... Objectives: Evaluate performance and resistance to gap formation of a non-absorbable, barbed, monofilament suture, in comparison with a non-absorbable, smooth, monofilament polypropylene suture, in two different suture patterns: three-loop pulley (3LP) and modified Bunnell-Mayer (BM). Sample size: Seventy-two medium-sized cadaveric superficial digital flexor muscle tendon units. Methods: After manual transection and suture repair, individual specimens were placed in an electromechanical tensile testing machine and tested to monotonic failure using tensile ramp loading. Video data acquisition allowed evaluation of failure mode and quantification of gap formation. Results: Incidence of gap formation between tendon ends was significantly greater in tenorrhaphies repaired with barbed suture compared to those repaired with smooth polypropylene. Use of a 3LP suture pattern caused significantly less gapping between tendon ends when compared to the BM pattern. Conclusion: Smooth polypropylene suture was consistently superior in load performance than a unidirectional barbed suture. The 3LP pattern was more resistant than a BM pattern at preventing gap formation. Clinical significance: Smooth polypropylene should be recommended over barbed unidirectional suture for use in canine tendinous repair to provide increased resistance to gap formation. The 3LP is superior to the BM suture pattern, requiring significantly more force to cause tenorrhaphy gap formation and failure, which may translate to increased accrual of repair site strength and tendinous healing in clinical situations.... D. J. Duffy (1), R. P. Main (2, 3), G. E. Moore (4), G. J. Breur (1), R. P. Millard (1) 24445 2015-06-03 13:14:34 Comparison of double locking plate constructs with single non-locking plate constructs in single... Objective: To evaluate the biomechanical properties of single 3.5 mm broad dynamic compression plate (DCP) and double 3.5 mm String-of-Pearls (SOP) plate constructs in single-cycle bending and torsion. We hypothesized that the double SOP construct would outperform the broad DCP in both bending and torsional testing. Methods: Broad DCP plates and double 3.5 mm SOP plates were secured to a previously validated bone model in an effort to simulate bridging osteosynthesis. Constructs were tested in both four-point bending and torsional testing. Results: The double SOP constructs had significantly greater bending stiffness, bending strength, bending structural stiffness, and torsional stiffness when compared to the broad DCP constructs. The single broad DCP constructs had significantly higher yield torque and yield angles during torsional testing. Clinical relevance: Although the in vitro mechanical performance of the double SOP construct was significantly greater than the single broad DCP constructs under bending loads, the actual differences were small. Various patient, fracture, and implant factors must be considered when choosing an appropriate implant for fracture fixation.... K. D. Hutcheson (1), J. R. Butler (1), S. E. Elder (2) 24444 2015-06-03 13:13:45 Ahead of print: Tibial plateau levelling osteotomy in 69 small breed dogs using conically coupled... Objective: To report clinical experiences with the tibial plateau levelling osteotomy (TPLO) procedure in small breed dogs with cranial cruciate ligament (CCL) disease using specific, conically coupled, 1.9/2.5 mm locking plates and evaluating short-term complications and outcome. Methods: Medical records of small breed dogs (<15 kg) that underwent TPLO using 1.9/2.5 mm locking plates were reviewed retrospectively. The preoperative, postoperative and six to eight weeks postoperative tibial plateau angle (TPA) measurements were determined from the radiographic images. Lameness evaluation was assessed subjectively preoperatively and six to eight weeks postoperatively. Results: Sixty-nine small breed dogs (n = 79 stifles) were included in the study. Mean (± SD) preoperative TPA was 29.0 ± 3.4°, postoperative TPA was 5.8 ± 2.5°, and six to eight weeks postoperative TPA was 7.3 ± 4.1°. Sixteen complications occurred in 12 out of 79 TPLO procedures: three were intraoperative (intra-articular screw placement) and 13 were postoperative complications, of which nine were identified as minor complications not requiring surgical reintervention, and four as major complications requiring additional surgical intervention, including tibial tuberosity fracture (n = 1), osteomyelitis (n = 1), screw failure (n = 1), and plate breakage (n = 1). Lameness scores by clinical assessment reduced from a median value of 3/4 preoperatively to 1/4 at six to eight weeks postoperatively. Clinical significance: 1.9/2.5 mm locking plates appear to be a valid choice of implant for the stabilization of unilateral TPLO in small breed dogs.... G. Cosenza (1), U. Reif (1), F. M. Martini (2) 24443 2015-06-03 13:12:36 Histological and immunohistological analysis of degenerative changes in the cranial cruciate... Objective: To create a canine model of excessive tibial plateau angle (eTPA) and assess the chondroid metaplasia and extracellular matrix alteration in the cranial cruciate ligament. Methods: Seven mature female Beagles were included. Cylindrical osteotomy was performed bilaterally in the proximal tibia. The TPA was increased to approximately 40° in the left tibia (eTPA stifle) and left unchanged in the right tibia (control stifle). Exercise stress was started at three months postoperatively, and at 12 months postoperatively the dogs were euthanatized and the cranial cruciate ligaments were collected. The specimens were subjected to haematoxylin and eosin staining to assess the ligamentocyte morphology and immunostaining to assess the type I (COLI), type II (COLII), and type III (COLIII) collagen, and the sry-type HMG box 9 (SOX9) staining. Results: Macroscopic cranial cruciate ligament injury was absent in six dogs but present in the eTPA stifle of one dog, which was excluded from the analysis. The ligamentocyte density decreased and the percentage of round ligamentocytes increased in the eTPA stifles. The COLII, COLIII, and SOX9 staining increased significantly and COLI deposition decreased in the eTPA stifles compared to the control stifle. Clinical significance: The extracellular matrix changed, COLI deposition decreased, and COLIII and SOX9 staining increased in the cranial cruciate ligament of the eTPA stifles. SOX9 may contribute to COLII synthesis in the extracellular matrix of the cranial cruciate ligament in eTPA stifles, and eTPA may promote chondroid metaplasia and extracellular matrix alteration.... T. Ichinohe (1), N. Kanno (1), Y. Harada (1), T. Yogo (1), M. Tagawa (1), Y. Hara (1) 24398 2015-05-22 10:42:49 In vitro biomechanical testing of different configurations of acrylic external skeletal fixator... Objective: To evaluate the in vitro biomechanical properties of four different configurations of acrylic external skeletal fixator constructs. Materials and methods: Simulated bone constructs were prepared using two segments of 20 mm ultra-high-density polyethylene rods with a gap of 5 mm. The full pins (1.5 mm) were passed through the proximal and distal segments of ultra-high-density polyethylene rods, in the same plane, parallel to each other in configuration U, and were crossed in the M1, M2 and C configurations at a 90° angle to each other. Configuration U was a single bilateral uniplanar construct, M1 was a double orthogonal bilateral construct, M2 was a double orthogonal bilateral construct with proximal and distal connecting articulations, and C was a double orthogonal bilateral construct with proximal and distal circumferential articulations. Temporary scaffolds of different external skeletal fixator configurations were constructed using commercially available polyvinyl chloride pipes (20 mm) connected and secured to the fixation pins at a fixed distance from the rods. Acrylic powder (polymer) mixed with liquid (monomer) was poured into the pipes and allowed to solidify to form the side bars and rings. The external skeletal fixator constructs were then subjected to axial compression, cranio-caudal three-point bending and torsion (n = 4 each) using a universal testing machine. Mechanical parameters, namely stress, strain, modulus of elasticity, stiffness and bending moment of fixator constructs, were determined from load-displacement curves. Results: Configuration U was the weakest and configuration C was the strongest under all the testing modes. Under compression, the M1, M2 and C configurations were similar. Under bending, a significant difference was observed among the uniplanar, multiplanar and circular configurations with no difference between M1 and M2. However, under torsion, all the external skeletal fixator configurations differed significantly. Clinical significance: The freeform external skeletal fixator using acrylic as a replacement for a metallic bar may be useful to treat bone fractures and luxations in small animals, as it is mechanically strong, lightweight, economical, and pins can be passed from any direction depending upon the clinical situation.... S. K. Tyagi (1), H. P. Aithal (1), P. Kinjavdekar (1), Amarpal (1), A. M. Pawde (1), T. Srivastava (1), J. Singh (1), D. N. Madhu (1) 24397 2015-05-22 10:40:48 Veterinary Orthopedic Society - 42nd Annual Conference 24353 2015-05-12 16:28:51 Promotion of Bone Regeneration K. A. Johnson 24352 2015-05-12 14:54:22 Comparison of autogenous cancellous bone grafting and extracorporeal shock wave therapy on osteotomy... Objectives: To compare optical values in the osteotomy gap created after a tibial tuberosity advancement (TTA) treated with autogenous cancellous bone graft, extracorporeal shock wave therapy, a combination of autogenous cancellous bone graft and extracorporeal shock wave therapy, and absence of both autogenous cancellous bone graft and extracorporeal shock wave therapy using densitometry. Methods: Dogs that were presented for surgical repair of a cranial cruciate ligament rupture were randomly assigned to one of four groups: TTA with autogenous cancellous bone graft (TTA-G), TTA with autogenous cancellous bone graft and extracorporeal shock wave therapy (TTA-GS), TTA with extracorporeal shock wave therapy (TTA-S), and TTA with no additional therapy (TTA-O). Mediolateral radiographs at zero, four and eight weeks after surgery were evaluated to compare healing of the osteotomy gap via densitometry. An analysis of variance was used to compare the densitometric values between groups. Results: At four weeks after surgery, a significant difference in osteotomy gap density was noted between TTA-GS (8.4 millimetres of aluminium equivalent [mmAleq]) and TTA-S (6.1 mmAleq), and between TTA-GS (8.4 mmAleq) and TTA-O (6.4 mmAleq). There were no significant differences noted between any groups at the eight week re-evaluation. Clinical significance: There were no significant differences in the osteotomy gap density at eight weeks after surgery regardless of the treatment modality used. The combination of autogenous cancellous bone graft and extracorporeal shock wave therapy may lead to increased radiographic density of the osteotomy gap in the first four weeks after surgery. Densitometry using an aluminium step wedge is a feasible method for comparison of bone density after TTA in dogs.... K. Barnes (1), O. Lanz (1), S. Werre (1), K. Clapp (1), R. Gilley (1) 24274 2015-04-22 13:11:36 Distal tibial tuberosity translation using TTA implants for the treatment of patella alta in large... Introduction: Medial patellar luxation frequently occurs in dogs resulting in lameness with increasing incidence in large breed dogs. Patella alta has been defined as a patellar ligament length to patellar length ratio that is greater than two and may predispose to patellar luxation. Objective: To describe the surgical technique for stabilization of the distal translation of the tibial tuberosity using tibial tuberosity advancement plates and the clinical outcomes with follow-up for clinical cases of dogs. Methods: Dogs that were presented with the complaint of patellar luxation and that were concurrently diagnosed with patella alta and were greater than 20 kg in body weight underwent surgery using a tibial tuberosity advancement plate to stabilize the osteotomy. Radiographic assessment of A:PL distance (the ratio of the proximal aspect of the patella to the femoral condyle [A] to the patellar length [PL]), L:P ratio (ratio of the length of the patellar ligament to the diagonal length of the patella), and owner assessment were obtained. Results: Eleven stifles in nine dogs underwent surgical correction with a mean preoperative L:P ratio of 2.47. There were no complications and the lameness resolved clinically. The mean A:PL ratios preoperatively (2.6 ± 0.22) and postoperatively (2.1 ± 0.25) were significantly different (p = 0.0003). All owners were satisfied with the outcome and all dogs had a resolution of lameness with no recurrence of patellar luxation. Clinical significance: Stabilization of distal translation of the tibial tuberosity using tibial tuberosity advancement implants to correct patella alta in large breed dogs was feasible and resulted in good clinical outcome.... L. C. Pugliese (1), F. S. Pike (2), S. W. Aiken (2) 24273 2015-04-22 12:58:01 Single-stage bilateral tibial tuberosity advancement for treatment of bilateral canine cranial... Objective: To report complications in dogs with naturally occurring cranial cruciate ligament rupture following single-stage bilateral tibial tuberosity advancement (SS-BTTA) procedures, and to compare these complications to a population of dogs undergoing unilateral tibial tuberosity advancement (UTTA). Methods: Medical records and radiographs of client-owned dogs treated with tibial tuberosity advancement between August 2008 and December 2011 were reviewed. Forty-four client-owned dogs with bilateral cranial cruciate ligament rupture that underwent SS-BTTA procedures and 82 client-owned dogs that underwent UTTA procedures were randomly selected from our hospital population. Complications were recorded and analysed. Major complications were defined as fractures or any complication requiring a second surgery. Minor complications were any problem identified that did not require surgical management. Results: Incidence for major and minor complications in the UTTA group was 2.3% and 24.4%, respectively. Incidence for major and minor complications in the SS-BTTA group was 12.5% and 26.1%, respectively. Single-stage bilateral tibial tuberosity advancement procedures had a four- to five-fold increase in odds of a major complication (p... J. E. Kiefer (1), A. Langenbach (1), J. Boim (2), S. Gordon (1), D. J. Marcellin-Little (3) 24272 2015-04-22 12:57:57 Evaluation of a distractor to increase joint space of the stifle joint in dogs: a cadaveric study Objective: To evaluate the technical feasibility and efficacy of a joint distraction technique to increase the stifle joint space and assess potential soft tissue damage due to the distraction. Methods: Twenty stifle joints of twelve canine cadavers without evidence of disease were radiographically evaluated by medio-lateral, cranio-caudal and varus-valgus stressed projections. Joint distraction was applied with loads from 40 N up to 200 N, and the joint space achieved was measured on radiographic images. Distraction plus distension with saline was subsequently applied and measured. Varus-valgus stressed projections were repeated after distraction to evaluate a potential increase in joint laxity. Results: Distraction produced a significant increase of the joint space for most of the evaluated loads. Distraction plus distension produced a significant increase for most of the loads compared to the distraction alone. No ensuing joint laxity could be inferred from the post-distraction radiographic evaluation. Clinical significance: Stifle distraction produces an increase of the joint space, which is wider when intra-articular saline is injected. This may be potentially useful for improving joint structure visualization and facilitating arthroscopic procedures, thus reducing the potential for iatrogenic damage to intra-articular structures. No soft tissue damage could be inferred by radiographic pre- and post-procedure comparison. Further clinical studies are required to evaluate potential neurovascular complications.... G. L. Rovesti (1), V. Devesa-Garcia (2), P. G. Urrutia (3), F. San Roman (2), J. Rodriguez-Quiros (2) 24271 2015-04-22 12:57:50