Orthotics and prosthetics by 3D-printing: Accelerating its fabrication flow.

Orthoses and socket prostheses are rarely used orthopaedic devices in veterinary medicine. Recently, more pet owners have sought these treatments for pets with orthopaedic conditions. However, veterinarians often lack substantial scientific evidence on device outcomes and may expect high costs, the main limiting factor, if human orthopaedic market prices are assumed. This discrepancy creates an imbalance between pet owners' expectations, veterinarians' recommendations, and actual patient benefits. To address economic constraints and enhance knowledge about these devices, this study used 3D technology-namely 3D scanning and printing via fused deposition modelling-to design, modify, and manufacture orthoses and socket prostheses for ten patients, including nine dogs and one calf. An equation was devised and applied to all printed devices to streamline the resizing process for sockets and orthoses. The 3D-printed devices were fitted to the patients, and their adaptation was assessed using three novel scales based on prior scientific literature in the small animal orthopaedic field. The orthoses were well-tolerated, with successful and straightforward adaptation. Although socket prostheses were tolerated, the dogs' adaptation was suboptimal, while the calf demonstrated excellent and immediate adaptation.

Muscular morphometric study of the canine shoulder for the design of 3D-printed endoprostheses in dogs with osteosarcoma of the proximal humerus: a pilot cadaveric study by MRI.

OBJECTIVE: Osteosarcoma frequently affects the proximal humerus in dogs. In veterinary medicine, no therapeutic option for the treatment of osteosarcoma satisfactorily preserves limb function. 3D-printed personalized endoprosthesis offers a promising treatment option. Morphometric data, necessary for the design of the endoprosthesis, are currently lacking in canine patients. Our objective was to acquire the morphometric data necessary to refine the design of the endoprosthesis. ANIMAL: A single canine cadaveric thoracic limb. PROCEDURES: Sagittal proton-density, and sagittal, dorsal, and transverse T1-weighted sequences of the thoracic limb were acquired with a 1.5 Tesla Magnetic Resonance Imaging (MRI) unit. Nineteen muscles of interest were subsequently identified using medical imaging software (Mimics©) and their volume was reconstructed in 3D using computer-aided design (CATIA©). Mormophetric data were recorded for each of the 19 muscles. The same canine cadaver was then dissected to measure the same parameters. RESULTS: All muscles were successfully identified with data consistent with the dissected cadaveric data. Certain muscles were more challenging to isolate on MRI, namely the heads of the triceps brachii, superficial pectoral, and latissimus dorsi. The relative distribution of muscle volumes was similar to historical data. Muscle tissue density was not significantly affected by freezing (1.059 g/cm3). CLINICAL RELEVANCE: MRI is a useful tool to collect morphometric data but imperfect if used alone. This approach was the first attempt to validate more general morphometric data that could be used to refine the design of custom 3D-printed prostheses for limb-sparing of the proximal humerus. Further imaging studies are warranted to refine our model.

Patient specific, synthetic, partial unipolar resurfacing of a large talar osteochondritis dissecans lesion in a dog.

OBJECTIVE: To describe the application and early outcome of a custom-made unipolar partial tarsal replacement in a dog with an extensive medial talar ridge OCD. ANIMAL: A 7-month-old, 25 kg male Rhodesian Ridgeback with progressive left hindlimb lameness (grade III-IV/IV) and diagnosis of talar OCD. METHODS: The dog presented with progressive lameness attributed to extensive medial talar ridge OCD. Due to the severity of the lesion, a resurfacing procedure was chosen. Based on CT data, a bi-layered resurfacing implant consisting of a titanium socket and a polycarbonate urethane bearing surface was constructed. For intraoperative guidance, a set of matching drill guides were 3D-printed, along with some models of the affected talus, to allow for dry-lab training. Surgical implantation using a medial malleolar osteotomy to approach the lesion was without complications. Orthopedic follow-up examinations were conducted at 10 days, 4 weeks, 6 weeks, 6 months and 12 months. Radiographic examinations were included at the 6-week, 6-month, and 12-month follow-ups. RESULTS: Function improved considerably during the follow-up period with a lameness grade of 0-I/IV at the 12-month follow-up. ROM differed by 15° in flexion compared to the contralateral side, while there was no difference in extension. Moderate periarticular fibrosis was present at 12 months. Implant positioning was unchanged at follow-up-radiographic examination and there was only mild progression of osteoarthritis (OA). CONCLUSION: Patient specific instrumentation - guided tarsal OCD resurfacing with a synthetic patient-specific implant may be an effective treatment option.

Biocompatibility of the fiberoptic microneedle device chronically implanted in the rat brain.

The fiberoptic microneedle device (FMD) is a fused-silica microcatheter capable of co-delivery of fluids and light that has been developed for convection-enhanced delivery and photothermal treatments of glioblastoma. Here we investigate the biocompatibility of FMD fragments chronically implanted in the rat brain in the context of evaluating potential mechanical device failure. Fischer rats underwent craniectomy procedures for sham control (n = 16) or FMD implantation (n = 16) within the brain. Rats were examined daily after implantation, and at 14, 30, 90, and 180 days after implantation were evaluated via computed tomography of the head, hematologic and blood biochemical profiling, and necropsy examinations. Clinical signs of illness and distant implant migration were not observed, and blood analyses were not different between control and FMD implanted groups at any time. Mild inflammatory and astrogliotic reactions localized to the treatment sites within the brain were observed in all groups, more robust in FMD implanted groups compared to controls at days 30 and 90, and decreased in severity over days 90-180 of the study. One rat developed a chronic, superficial surgical site pyogranuloma attributed to the FMD silica implant. Chronically implanted FMD fragments were well tolerated clinically and resulted in anticipated mild, localized brain tissue responses that were comparable with other implanted biomaterials in the brain.

Reconstrução de palato com malha de polipropileno e prótese acrílica para correção de fístula oronasal adquirida em cão / Palate reconstruction with polypropylene mesh and acrylic prosthesis in dog for correcton of acquired oronosal fistulae

As fístulas oronosais adquiridas são defeitos que permitem a comunicação anormal entre as cavidades oral e nasal. Inúmeras causas podem ser atribuídas à etiologia de tal defeito. O presente trabalho visa relatar o caso de um cão com fístula oronasal adquirida que foi submetido à reconstrução cirúrgica do palato com o uso de malha de polipropileno e prótese acrílica. Após estabilização do quadro clínico e remoção manual das larvas, o paciente foi encaminhado para o desbridamento cirúrgico das lesões orais e correção do defeito no palato. A palatoplastia foi realizada com o uso da malha e resina de polimetilmetacrilato autopolimerizável. A malha foi suturada sobre o defeito palatino com pontos simples separados e fio náilon 3-0 nas extremidades da ferida. Em seguida, a resina foi preparada e, ao atingir consistência adequada, foi aplicada e modelada sobre o a malha de polipropileno com o auxílio de um descolador de Molt, sendo também suturada nas bordas da fístula com pontos simples separados e fio náilon 3-0. No mesmo tempo cirúrgico foi inserida uma sonda esofágica para alimentação enteral. Devido complicações cirúrgicas no pós operatório, o paciente foi submetido a mais duas intervenções cirúrgicas para desfecho satisfatório do tratamento. Conclui-se que associação entre a tela de polipropileno e a prótese acrílica foi uma alternativa exequível para a palatoplastia em cão.

Acquired oronosal fistulae are abnormal communication between the oral and nasal cavities. A oronasal fistula can be the result of different causes, like oral myiasis. The objetctive of these paper is to report the case of a dog with acquired oronasal fistula that underwent surgical reconstruction of the palate using polypropylene mesh and acrylic prosthesis. After stabilization of the patient ́s clinical condition and mecanic removal of the larvae, the dog was referred for surgical debridement of the oral lesions and correction of the defect in the palate. Palatoplasty was performed using a mesh and polymethylmethacrylate resin. The mesh was sutured over the palatal defect with separate simple suture and 3-0 naylon thread at the ends of the wound. Then, the resin was prepared and, upon reaching adequate consistency, it was applied and shaped over the polypropylene mesh with Molt peeler. It was also sutured on the edges of the fistula with separate simple suture and 3-0 nylon suture. At the same surgical time, an esophageal tube was inserted for enteral feeding. Due to complications, the dog underwent two more surgical interventions for a satisfactory treatment outcome. It is concluded that the association between the polypropylene mesh and the acrylic prosthesis was a practical alternative for palatoplasty in dogs after oral myiasis.

Occipital cranioplasty using customized titanium prosthesis yields successful outcome in association with foramen magnum decompression in dogs suffering by Chiari-like malformation.

OBJECTIVE: To describe the use of a customized 3-D-printed titanium prosthesis as adjunctive treatment for foramen magnum decompression (FMD) in dogs with Chiari-like malformation (CM) and syringomyelia (SM). ANIMALS: 8 dogs with clinical signs and MRI findings of CM-SM. PROCEDURES: 3-D reconstruction of CT images of the head was used to simulate an occipital craniectomy and design the prosthesis. FMD was performed, and the prosthesis was implanted. Follow-up was performed 1, 6, and 12 months later, and clinical status was scored. Repeated MRI images were compared to identify changes involving the neural structures, particularly the syrinx. RESULTS: All prostheses were easily positioned based on the preoperative 3-D models, with no complications. At 12 months after surgery, 3 dogs were free of previous medications, 4 were still receiving steroid medications but at lower doses, and 1 was occasionally receiving acupuncture. MRI of 5 dogs 6 to 20 months after surgery revealed resolution of SM (n = 1), reduced size of SM (3), or worse SM (1). All dogs showed an increase in size of the caudal cranial fossa. Dogs with a longer presurgical duration of the clinical signs and wider syrinx generally had worse outcomes than other dogs. CLINICAL RELEVANCE: Findings suggested that use of customized 3-D-printed titanium prosthesis and associated FMD can represent an adjunctive option to medically treated dogs with CM-SM. Although the small number of cases precludes definitive conclusions, early surgical treatment, particularly in dogs with a small syrinx, could ensure better long-term outcomes, as previously suggested.

Risk factors for surgical site infection associated with clean surgical procedures in dogs.

Surgical site infection (SSI) is associated with increased morbidity, cost and mortality in human medicine and with increased morbidity and cost in veterinary medicine. The aim of this study was to evaluate risk factors for SSI development after clean surgical procedures in dogs, treated at both first opinion clinics as well as referral hospitals. 1550 dogs scored 1 or 2 according to the American Society of Anesthesiologists (ASA), that underwent clean surgical procedures at 103 clinics located in Northern and Central Europe were included in the study. Data regarding the surgical procedure, surgery time use of perioperative antimicrobial prophylaxis (AMP), surgery type, intraoperative hypothermia, and the use of surgical implants were recorded according to predefined protocols. Active 30-day SSI surveillance was performed. A random effects logistic regression model was used to evaluate the association between the perioperative variables and SSI development. SSI was detected in 85/1550 dogs (5.5%); 25 occurred in the 500 orthopedic/neurosurgery procedures (5.0%), and 60 in the 1050 soft tissue procedures (5.7%). A total of 1524 dogs were included in the final multivariable model. Increased surgery time was the only variable associated with an increased risk of SSI. No association between the other risk factors evaluated in the study and SSI occurrence was detected. Efforts must therefore be made to keep the surgery time as short as possible. Orthopedic and neurosurgical procedures including those where an implant is placed should not automatically be regarded as high-risk procedures benefiting from perioperative AMP.

[Dog license taxes and tags]. / Hundesteuern und Hundemarken.

INTRODUCTION: Based on a donation of more than 1000 Swiss dog license tags to the museum of veterinary medical history in Zurich, historic dog license taxes and tags are compared between Switzerland and other European countries. In 2006 the microchip was launched as mandatory identification for dogs in Switzerland and dog license tags became redundant.

INTRODUCTION: Dans le cadre du don d'une collection de plus de 1000 médailles d'identité suisses pour chiens au Musée d'histoire de la médecine vétérinaire de Zurich, le sujet des taxes et médailles pour chiens est étudié en Suisse et comparé à d'autres pays européens. Avec l'introduction de l'identification des chiens au moyen d'une puce électronique en 2006, il n'était plus nécessaire de remettre ces médailles.

Detection of atrial fibrillation with implantable loop recorders in horses.

BACKGROUND: Cardiac arrhythmias in horses are diagnosed by auscultation or electrocardiogram (ECG), which results in a low sensitivity for detecting arrhythmias that occur sporadically. Implantable loop recorders (ILRs) are small ECG devices placed subcutaneously, to automatically detect arrhythmias in human patients. OBJECTIVES: To test ILRs ability to detect atrial fibrillation (AF) in horses. Furthermore, we hypothesised that anatomical location of the implant site might influence signal quality. Signal quality was evaluated both during exercise and over time. STUDY DESIGN: Experimental study. METHODS: In five Standardbred mares, eleven ILRs were implanted subcutaneously in up to three different positions (Front: pectoral region, Left-6: sixth left intercostal space and Ventral: xiphoid region) and AF induced. The R- and T-wave amplitudes were measured in all positions over time during AF. AF burden automatically registered by the ILRs over a 2-month period was compared with selected Holter ECG recordings. RESULTS: All three positions had stable R- and T-wave amplitudes during the study period and were of sufficient quality to allow AF detection at rest. The position Left-6 showed significantly higher R- and T-wave amplitudes compared with the other positions. During submaximal exercise only the Left-6 position was able to record ECG signals of diagnostic quality. No position yielded diagnostic signals at maximum exercise due to artefacts. MAIN LIMITATIONS: Few horses and ILRs included and no spontaneous AF episodes were studied. CONCLUSIONS: This preliminary study indicates that ILRs can be used for AF detection in horses, but the anatomical location is important for optimal ECG quality. Despite insufficient quality during exercise, ILRs were suitable for AF detection at rest. Therefore, the ILR may be a valuable diagnostic tool for detecting paroxysmal AF in horses.

Risk factors for reluxation after toggle rod stabilization for treatment of coxofemoral luxation in 128 dogs.

OBJECTIVE: Evaluate the risk factors for reluxation and outcomes for dogs with a toggle rod construct. STUDY DESIGN: Retrospective case series. ANIMALS: One hundred twenty-eight client-owned dogs. METHODS: Medical records from 2007 to 2018 were reviewed for signalment, history, surgery, and outcome for dogs with a coxofemoral luxation repaired with a commercial toggle rod and nylon monofilament suture construct. Univariate and multiple logistics regression analysis were performed to assess risk factors associated with postoperative luxation. Primary veterinarians and owners were contacted for follow-up via telephone or electronic communication. RESULTS: The overall complication rate was 24.2%, and the reluxation rate was 14.8%. There was a decreased risk of reluxation when the cause was traumatic in origin (odds ratio [OR] 0.10) or when the lameness was severe at presentation (OR 0.42). Fifteen of 58 (25.9%) owners contacted completed a follow-up survey. CONCLUSION: Dogs with nontraumatic, low impact luxations were at a higher risk for reluxation. CLINICAL SIGNIFICANCE: Dogs of any body condition with a traumatic coxofemoral luxation are at lowest risk for reluxation.

Radiographic and Biomechanical Assessment of Three Implant Designs for Canine Cementless Total Hip Replacement.

OBJECTIVE: The aim of this study was to evaluate the relationship between radiographic fit/fill measurements and biomechanical performance of three canine cementless total hip implant designs using an in vitro biomechanical testing protocol that replicates compression and torsion. STUDY DESIGN: Eighteen (six/group) canine cadaveric femurs were implanted with one of three cementless total hip implant designs: (1) collarless, (2) collared or (3) lateral bolt stems. Femoral length, canal flare index (CFI), canal fill, stem fit, stem level and stem angle were measured as independent variables. Biomechanical performance was tested using physiological, non-destructive gait loading (loading protocols) and destructive testing (failure protocols). RESULTS: During loading protocols, compressive stiffness was influenced by stem level (p < 0.05) and torsional stiffness was influenced by stem level and CFI for collarless stems (p < 0.05). During failure protocols, peak load was influenced by mediolateral (ML) stem angle (p < 0.05) and CFI (p < 0.01) for collarless stems and CFI for lateral bolt stems (p < 0.05). Peak torque was influenced by ML stem angle, craniocaudal stem angle and CFI for collarless stems (p < 0.05) and average ML fill for collared stems (p < 0.05). CONCLUSION: Biomechanical performance of collarless stems in cementless hip arthroplasty is more impacted by radiographic fit/fill than lateral bolt and collared stems. As a result, collarless stems may be more dependent on preoperative fit and intraoperative precision.

Treatment of a large osseous defect in a feline tarsus using a stem cell-seeded custom implant.

The aim of this study is to describe the treatment of an infected segmental bone defect in a cat using a novel, custom-designed titanium implant seeded with adipose-derived stem cells (AdMSCs) to facilitate osseous ingrowth and preserve limb function. Large bone defects occur secondary to trauma, infection, or neoplasia and often result in amputation. We established a novel autologous AdMSC-impregnated trabecular metal spacer made using 3D printing, to bridge the distal tibia and metatarsal bones in the left pelvic limb of a cat that had previously undergone right pelvic limb amputation. Six months postoperatively, there was radiographic evidence of bone growth and implant integration. A titanium spacer seeded with AdMSCs successfully encouraged bone ingrowth in a large defect site and successfully preserved limb function. However, further studies are needed to justify the use of differentiated stem cell impregnated mesh as a framework to bridge large bone defects.

Schedule feasibility and workflow for additive manufacturing of titanium plates for ranioplasty in canine skull tumors.

BACKGROUND: Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty immediately following craniectomy. RESULTS: Computed tomography scans from patients with tumors of the skull were considered and 3 cases were selected. Images were imported into a DICOM image processing software and tumor margins were determined based on agreement between a board-certified veterinary radiologist and veterinary surgical oncologist. Virtual surgical planning was performed and a bone safety margin was selected. A defect was created to simulate the planned intraoperative defect. Stereolithography format files of the skulls were then imported into a plate design software. In collaboration with a medical solution centre, a custom titanium plate was designed with the input of an applications engineer and veterinary surgery oncologist. Plates were printed in titanium and post-processed at the solution centre. Total planning time was approximately 2 h with a manufacturing time of 2 weeks. CONCLUSIONS: Based on the findings of this study, with access to an advanced 3D metal printing medical solution centre that can provide advanced software and printing, patient-specific additive manufactured titanium implants can be planned, created, processed, shipped and sterilized for patient use within a 3-week turnaround.

Management of postoperative dysphagia after prosthetic laryngoplasty or arytenoidectomy.

OBJECTIVE: To evaluate the efficacy of various treatments for dysphagia after laryngeal surgery. STUDY DESIGN: Retrospective. ANIMALS: Horses treated for dysphagia after laryngeal surgery. METHODS: Medical records of horses treated for dysphagia after prosthetic laryngoplasty (PLP) or partial arytenoidectomy (PA) were reviewed. Signalment, prior surgery, preoperative videoendoscopic diagnosis, and surgical treatments were recorded. Short- and long-term follow-up were obtained. Chi-square and logistical regression were performed to correlate independent variables and outcomes. RESULTS: Forty-four percent of horses with prior PLP and 88% of horses with prior PA had persistent resting dorsal displacement of the soft palate (DDSP). Vocal fold augmentation (VFA) as a single treatment was most commonly performed (n = 22), followed by laryngoplasty removal (LPR; n = 1). Fifteen horses received a combination of treatments: VFA (n = 15), LPR (n = 4), laryngeal tie-forward (LTF; n = 2), and esophageal release (n = 1). Short-term clinical outcomes were reported; 80% of horses treated with VFA (n = 35) had resolution of dysphagia, and 20% were improved. Among the 33 horses available to long-term follow-up, 31 (94%) returned to some level of work, and DDSP during work was reportedly resolved in 23 of 25 horses. CONCLUSION: Vocal fold augmentation resulted in resolution of symptoms relating to dysphagia in 81% of horses. Twenty percent of horses treated with LPR had sustained resolution of dysphagia. A combination of LPR, VFA, LTF was performed in 18% of horses. CLINICAL SIGNIFICANCE: Treatment options directed at altering laryngeal geometry and/or position of the larynx were successful in resolving 86% of dysphagia in horses previously regarded as very difficult to treat.

Experimental Basis for Creating an Osseointegrated Neural Interface for Prosthetic Control: A Pilot Study in Rabbits.

INTRODUCTION: While debate persists over how to best prevent or treat amputation neuromas, the more pressing question of how to best marry residual nerves to state-of-the-art robotic prostheses for naturalistic control of a replacement limb has come to the fore. One potential solution involves the transposition of terminal nerve ends into the medullary canal of long bones, creating the neural interface within the bone. Nerve transposition into bone is a long-practiced, clinically relevant treatment for painful neuromas. Despite neuropathic pain relief, the physiological capacity of transposed nerves to conduct motor and sensory signals required for prosthesis control remains unknown. This pilot study addresses the hypotheses that (1) bone provides stability to transposed nerves and (2) nerves transposed into bone remain physiologically active, as they relate to the creation of an osseointegrated neural interface. METHODS: New Zealand white rabbits received transfemoral amputation, with the sciatic nerve transposed into the femur. RESULTS: Morphological examination demonstrates that nerves remain stable within the medullary canal, while compound nerve action potentials evoked by electrical stimulation of the residual nerve within the bone could be achieved at 12 weeks (p < 0.0005). CONCLUSION: Transposed nerves retain a degree of physiological function suitable for creating an osseointegrated neural interface.

Dimensões da patela relacionadas à massa corporal do cão para emprego na confecção de prótese: estudo em cadáver / Patellar dimensions related to canine body mass for use in the manufacture of prosthesis: cadaver study

O objetivo deste trabalho foi mensurar as dimensões da patela de cadáveres caninos e avaliar sua relação com a massa corporal. Para a realização das medidas patelares, foram utilizados 70 cadáveres de cães adultos, com massa corpórea de 1 a 50kg, sem evidência clínica de afecção na articulação femorotibiopatelar. Com auxílio de um paquímetro, foram mensurados os comprimentos externo e interno, a largura externa no terço médio, a largura e a espessura internas nos terços proximal, médio e distal das patelas. Também foram mensuradas a largura nos terços proximal, médio e distal, a profundidade nos terços proximal, médio e distal do sulco troclear; essas medidas foram exclusivamente internas. Observou-se, de forma geral, forte correlação entre as medidas patelares e a massa corporal de cadáveres de cães. Nas condições deste estudo, pode-se concluir que o tamanho da patela varia segundo a massa corporal do cão e que essas medidas devem ser consideradas ao se planejar uma substituição protética.(AU)

The aim of this study was to measure the canine cadaver patellar dimensions and evaluate its relationship with body mass. 70 cadavers of adult dogs were used, with a body mass between 1 and 50kg, without clinical evidence of affection in the stifle joint. The external and internal lengths, external width in the middle third, width and thickness of the proximal, middle and distal thirds were measured using a pachymeter. The width was also measured in the proximal third, middle third and distal third, depth in the proximal third, middle third and distal third of the trochlear groove; these measurements were exclusively internal. A strong correlation was observed between the patellar dimension and body mass of canine cadavers. Under this study conditions, it is possible to conclude that the patellar size varies according to the canine body mass and these measures should be considered when planning a prosthetic replacement.(AU)

Limb-sparing in dogs using patient-specific, three-dimensional-printed endoprosthesis for distal radial osteosarcoma: A pilot study.

Limb-sparing for distal radial osteosarcoma has a high rate of complications. Using personalized three-dimensional (3D)-printed implants might improve outcome. The goals of this study were to optimize use of patient-specific, 3D-printed endoprostheses for limb-sparing in dogs in the clinical environment and to report the outcome. This was a pilot study where five client-owned dogs were enrolled. Computed tomography (CT) of the thoracic limbs was performed, which was used to create patient-specific endoprostheses and cutting guides, and repeated on the day of surgery. Intra-arterial (IA) carboplatin was introduced in the clinical management. Limb-sparing was performed. Outcome measures were time required to produce the endoprosthesis and cutting guide, fit between cutting guide and endoprosthesis with host bones, gait analysis, size of the tumour, percent tumour necrosis, complications, disease-free interval (DFI) and survival time (ST). Four dogs received IA carboplatin. Excessive tumour growth between planning CT and surgery did not occur in any dog. The interval between the CT and surgery ranged from 14 to 70 days. Fit between the cutting-guide and endoprosthesis with the host bones was good to excellent. At least one complication occurred in all dogs. Two dogs were euthanized with STs of 192 and 531 days. The other dogs were alive with a follow up of 534 to 575 days. IA chemotherapy is a promising strategy to minimize the risk of excessive tumour growth while waiting for the endoprosthesis and cutting-guide to be made. The design of the cutting-guide was critical for best fit of the endoprosthesis with host bones.

Torsional comparative biomechanical test of modified tibial-plateau-leveling osteotomy plate and locking plate in canine synthetic tíbias / Teste de torção biomecânica comparative de placa de TPLO modificada e placa bloqueada em tibia sintética canina

The objective of this study was to develop a locked tibial-plateau-leveling osteotomy (TPLO) plate and to compare this implant with the conventional bone fixation method using a locked plate to determine bone stabilization against torsion forces. Maximum force, angle at peak torque, and stiffness values were determined. Ten synthetic tibias were used, divided into 2 groups. The results in Group 1 (modified TPLO plate) and Group 2 (locked plate) were assessed using analysis of variance and the means were compared using Tukey's test at 5% probability. There were significant differences in the angle at peak torque and stiffness. The group Modified TPLO plate had higher mean values of stiffness compared with Group locked plate. Group locked plate showed a greater angle at peak torque compared with Group modified TPLO plate. All constructs failed due to tibial fractures distal to the plate. The modified TPLO plate presented higher stiffness indexes than conventional locked plate in torsion. The locked plate presented greater elasticity than modified TPLO plate having greater angle at the peak of torque.(AU)

O objetivo do presente estudo foi desenvolver placa de TPLO bloqueada modificada e avaliar, em ensaio de torção, a estabilização óssea proporcionada pelo implante desenvolvido comparativamente a método de fixação óssea convencional com placa reta bloqueada. As variáveis obtidas foram força máxima, ângulo no pico de torque e rigidez. Foram utilizadas 10 tíbias sintéticas, dividas em dois grupos. Os resultados obtidos do grupo 1 (placa TPLO modificada) e do grupo 2 (placa bloqueada) foram submetidos à análise de variância, e as médias comparadas entre si pelo teste de Tukey a 5% de probabilidade. Houve diferença significativa em relação às variáveis, ângulo no pico de torque e rigidez. Na variável rigidez, a média do grupo placa de TPLO modificada foi maior que a do grupo placa reta bloqueada. Em relação à variável ângulo no pico de torque, o grupo placa reta bloqueada foi superior ao grupo placa de TPLO modificada. Todas as montagens falharam devido à quebra do corpo de prova distal à placa. Conclui-se que a placa de TPLO modificada apresentou maior índice de rigidez que a placa reta convencional sob força de torção. A placa reta bloqueada apresentou maior ângulo no pico de torque, sendo, portando, mais elástica.(AU)

Advances in Exotic Animal Osteosynthesis.

Exotic animal orthopedics has not incorporated the most recent progress made in small animal surgery or human medicine. Although minimally invasive osteosynthesis has been incorporated as a routinely used alternative in small animals, its use in exotic animals is still in its infancy. This article compliments the reviews of orthopedics in small mammals, birds, and reptiles in the previous issue. It reviews relevant recent studies performed in laboratory animals about new orthopedic materials and techniques showing potential to become incorporated into the routine orthopedic treatment of exotic animals in the coming years.

Investigation of a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament-deficient stifle joints in adult cattle.

OBJECTIVE: To evaluate a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament (CCL)-deficient stifle joints in adult cattle. SAMPLE: 13 cadaveric bovine stifle joint specimens. PROCEDURES: In the first of 3 study phases, the most isometric points on the distal aspect of the femur (distal femur) and proximal aspect of the tibia (proximal tibia) were determined from measurements obtained from lateromedial radiographs of a stifle joint specimen maintained at angles of 135°, 90°, 65°, and 35°. During phase 2, 800-lb-test monofilament nylon leader line was cut into 73-cm-long segments. Each segment was secured in a loop by use of 2, 3, or 4 crimping sleeves such that there were 12 replicates for each construct. Each loop was distracted to failure at a constant rate of 1 mm/s. Mean force at failure and elongation and mode of failure were compared among the 3 constructs. During phase 3, bone tunnels were created in the distal femur and proximal tibia at the isometric points identified during phase 1 in each of 12 CCL-deficient stifle joint specimens. The 3-sleeve construct was applied to each specimen. Specimens were distracted to failure at a constant rate of 1 mm/s. RESULTS: Among the 3 constructs evaluated, the 3-sleeve construct was considered optimal in terms of strength and amount of foreign material. In phase 3, all replicates failed because of suture slippage. CONCLUSIONS AND CLINICAL RELEVANCE: Use of 800-lb-test monofilament nylon leader line as a prosthesis might be a viable alternative for extracapsular stabilization of CCL-deficient stifle joints in adult cattle. Further in vivo studies are necessary.