Traumatic medial luxation of the triceps brachii tendon with medial subluxation of the elbow joint in a dog.

OBJECTIVE: To describe the surgical reduction of luxation of the triceps brachii tendon in a dog. ANIMAL: One 2.5-year-old 2.58 kg castrated male toy poodle. STUDY DESIGN: Clinical case report. METHODS: The dog displayed intermittent, non-weight bearing lameness of the right forelimb for approximately 18 months before presenting at the veterinary medical center. Medial subluxation of the right elbow joint was detected by palpation. The Campbell test was consistent with an increased range of motion during supination. At ultrasonographic examination, medial luxation of the triceps brachii tendon was noted, whereas collateral ligaments appeared normal. No skeletal deformities were found on radiographs of the right forelimb. The luxation of the triceps brachii tendon was surgically corrected with antirotational suture, a stopper pin, medial retinaculum release, and imbrication of the lateral retinaculum. RESULTS: The right triceps brachii tendon and elbow joint were successfully reduced. Gait returned to normal by 55 days postoperatively. No implant failure or recurrence were observed 3.5 years after surgery. CONCLUSION: Surgical reduction of a luxation of the triceps brachii tendon in a dog resolved lameness and restored the range of motion of the affected elbow, leading to good long-term outcome.

Repair of segmental radial defects in dogs using tailor-made titanium mesh cages with plates combined with calcium phosphate granules and basic fibroblast growth factor-binding ion complex gel.

Repair of large segmental defects of long bones are a tremendous challenge that calls for a novel approach to supporting immediate weight bearing and bone regeneration. This study investigated the functional and biological characteristics of a combination of a tailor-made titanium mesh cage with a plate (tTMCP) with tetrapod-shaped alpha tricalcium phosphate granules (TB) and basic fibroblast growth factor (bFGF)-binding ion complex gel (f-IC gel) to repair 20-mm segmental radial defects in dogs. The defects were created surgically in 18 adult beagle dogs and treated by implantation of tTMCPs with TB with (TB-gel group) or without (TB group) f-IC gel. Each tTMCP fitted the defect well, and all dogs could bear weight on the affected limb immediately after surgery. Dogs were euthanized 4, 8 and 24 weeks after implantation. Histomorphometry showed greater infiltration of new vessels and higher bone union rate in the TB-gel group than in the TB group. The lamellar bone volume and mineral apposition rate did not differ significantly between the groups, indicating that neovascularization may be the primary effect of f-IC gel on bone regeneration. This combination method which is tTMCP combined with TB and f-IC gel, would be useful for the treatment of segmental long bone defects.

Comparison of the long-term effects on rabbit bone defects between Tetrabone and ß-tricalcium phosphate granules implantation.

Tetrabone is a newly developed granular artificial bone. The 1-mm Tetrabone has a four-legged structure. In this study, the long-term effect of implanting Tetrabone or ß-TCP granules in rabbit femoral cylindrical defects was evaluated. The rabbits were euthanized at 4, 13, and 26 weeks after implantation. Micro-CT was conducted to evaluate the residual material volume and the non-osseous tissue volume. New bone tissue areas were measured by histological analysis. Micro-CT imaging showed that the residual material volume in the ß-TCP group had decreased significantly at 4 weeks after implantation (P < 0.05) and that the ß-TCP granules had nearly disappeared at 26 weeks after implantation. In the Tetrabone group, it did not significantly change until 13 weeks after implantation; it then continued to decrease slightly until 26 weeks after implantation. The non-osseous volume increased in the ß-TCP group, whereas that of the Tetrabone group decreased (P < 0.05). Histological examination showed that the new bone areas were significantly greater in the Tetrabone group than in the ß-TCP group at 13 and 26 weeks. In conclusion, resorption of ß-TCP granules occurs before sufficient bone formation, thereby allowing non-osseous tissue invasion. Tetrabone resorption progressed slowly while the new bone tissues were formed, thus allowing better healing. Tetrabone showed better osteoconductivity, whereas the ß-TCP granules lost their function over a long duration. These results may be caused by the differences in the absorption rate of the granules, intergranular pore structure, and crystallinity of each granule.

Forelimb lameness caused by Malignant peripheral nerve sheath tumors of the median nerve in a dog: a case report.

An 8-year-old Portuguese Water Dog presented with a 5-month history of left forelimb lameness. There was palmar pain. Ultrasonography revealed enlargement of the left median nerve. Subsequent MRI also showed enlargement of the median nerve in the distal palmar to the mid-forearm region. Rapid intraoperative diagnosis suggested Malignant peripheral nerve sheath tumors (MPNST) and a neurotomy was performed. The lameness had almost disappeared in 1 month after surgery. Recurrence occurred 26 months postoperatively and the forelimb was amputated. At 950 days after the neurotomy, radiography revealed lung metastasis, and the dog died 988 days after the neurotomy. Neurotomy for MPNST should be performed with caution until more information is available regarding methods for early detection, margin determination, and indication determination for neurotomy.

Measurement of Femoral Trochlear Morphology in Dogs Using Ultrasonography.

OBJECTIVE: The aim of this study was to examine a method for measuring femoral trochlear morphology in dogs using ultrasonography, and survey femoral trochlear morphology in skeletally normal dogs. STUDY DESIGN: To examine the validity of ultrasonography, three raters measured the sulcus angle (SA; the angle between the medial and lateral facets) five times in five skeletally normal dogs. Intra- and interrater reliabilities were then calculated. We also calculated the correlation coefficient between SAs measured using ultrasonography and computed tomography (CT) or magnetic resonance imaging (MRI). Then, we surveyed the femoral trochlear morphology in skeletally normal dogs using ultrasonography. RESULTS: The intra- and interrater reliability for SAs measured using ultrasonography was good, and the correlation coefficient between SAs measured using ultrasonography and CT, or MRI, was strong. In skeletally normal dogs, the SAs for osseous contours decreased until 6 months of age. However, the SAs for cartilaginous contours did not change during the growth period. CONCLUSION: The ultrasonographic measurement method is reliable for the evaluation of femoral trochlear morphology in dogs. The contour of the articular cartilage surface of the femoral trochlea is already determined early in life, and ossification of the articular cartilage of the femoral trochlea proceeds until 6 months of age. The results of this study will provide crucial information for the evaluation of femoral trochlear morphology in dogs.

Computed Tomographic Measurements of the Sulcus Angle of the Femoral Trochlea in Small-Breed Dogs with and without Medial Patellar Luxation.

Trochleoplasty is often performed in dogs with medial patellar luxation (MPL); however, the current guidelines on when to perform a trochleoplasty in dogs are vague. The sulcus angle (SA) is used to assess the femoral trochlear morphology in humans. The aim of this study is to describe a method to measure the SA and other parameters of trochlea morphology in dogs using computed tomography. First, we searched for a suitable measuring location for the SA. Transverse images of the femurs were obtained as perpendicular planes to the tangent of the femoral trochlea which was 0 to 60 degrees (every 5 degrees) to the anatomical axis of the femur. The deepest point of the femoral trochlea was found in the transverse images perpendicular to the tangent of the femoral trochlea which was at 15 degrees to the anatomical axis of the femur. The SA and the other parameters of femoral trochlea morphology were measured at the deepest point of the femoral trochlea. The SA of the stifle joints with grade 3 and 4 MPL was significantly higher than the SA of stifle joints not affected by MPL. There was no significant difference in the SA between dogs affected by grade 1 and 2 MPL and dogs not affected by MPL. Further studies are needed to establish whether the SA can be used as selection criteria for trochleoplasty.

Evaluation of the susceptibility artifacts and tissue injury caused by implanted microchips in dogs on 1.5 T magnetic resonance imaging.

Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. The purpose of this study was to investigate these complications in dogs with implanted microchips by evaluating MR images and the histopathological changes after 1.5 Tesla (T) MRI. Five dogs underwent microchip implantation in the cervicothoracic area. One month later, the area was imaged using 1.5T MRI in three dogs. The microchips were removed surgically together with the surrounding tissue in all dogs. There was significant signal loss and image distortion over a wide range around the area where the microchip was implanted. This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. The artifact was more extensive in T2*-weighted images (gradient-echo) and less extensive in proton density-weighted images (fast spin-echo with short echo time). Histopathologically, all microchips were well-encapsulated with granulation tissue, and there were no evidence of migration of microchips. Cell debris and a moderate number of degenerated cells with fibrin were seen in the inner layer of the granulation tissue in each dog that underwent MRI. These changes were very subtle and did not seem to be clinically significant. The results of this study suggest that, in 1.5T MRI, susceptibility artifacts produced by implanted microchips can be marked, although the dogs with implants appeared to be scanned safely.

Preoperative planning for tibial plateau leveling osteotomy based on proximal tibial width.

The purpose of this study was to evaluate the applicability and feasibility of a novel preoperative planning method for tibial plateau leveling osteotomy (TPLO) based on the width of the proximal tibia. All TPLO procedures were performed by the same surgeon. In preoperative planning, the width of the tibial crest to the caudal edge of the medial tibial plateau (W) was measured, and the saw blade size that was closest to the distance between the point of the cranial third W and the intercondylar tubercles was selected. The postoperative tibial plateau angle (TPA), distance of eccentricity (DOE), and minimum thickness of the tibial tuberosity remaining cranial to the osteotomy (tibial tuberosity width; TTW) were documented. Complications in the perioperative and follow-up periods were documented. Thirty-one TPLO procedures were performed in 28 dogs, including both small and large breeds. The postoperative TPA was 8.4 ± 2.0° and the DOE was 3.55 ± 2.88 mm. The ratio of the TTW to the preoperative W was 0.27 ± 0.06. There were no major complications, such as fractures of the tibial tuberosity or implant breakage. This preoperative planning method allowed appropriate planning for TPLO with a clear index that was based on the size of the tibia rather than the breed or weight of the dog. This method should be of benefit to the surgeon, whether an expert or a novice, and contribute to the success of TPLO.

Efficacy of frozen autograft treated with liquid nitrogen in limb-sparing surgery in feline scapular osteosarcoma: A case report.

In recent years, a novel technique of limb preservation has been used in human medicine that involves frozen autograft treated with liquid nitrogen. In this case, frozen autograft treatment along with shoulder joint reconstruction was performed in an 11-year-old cat with osteosarcoma of the distal scapula. Surgical site infection, shoulder dislocation, local recurrence, and pulmonary metastases were not reported for 24 months after surgery. Moreover, the patient was able to bear weight on the operated limb after 2 months of surgery, and excellent limb function without lameness was demonstrated after 15 months. The frozen autograft technique is advantageous because it is inexpensive, simple, and retains its initial strength after treatment, and could be a novel treatment in feline osteosarcoma.

A Biomechanical Comparison of Three Miniature Locking Plate Systems in a Rabbit Radial and Ulnar Fracture Model.

OBJECTIVE: The aim of this study was to evaluate the biomechanical properties of three different miniature locking plate systems used to fixate radial and ulnar fractures in toy breed dogs. Implant size, shape, material and locking systems differ, and their influence on the fracture healing process is unknown. In the present study, we aimed to investigate this matter in vivo using rabbit radial and ulnar fracture models. STUDY DESIGN: Eighteen rabbits were randomly divided into three groups, and the left radius and ulna were osteotomized to create fracture models. The osteotomies were then fixated using either the TITAN LOCK 1.5, Fixin micro or LCP 1.5 system. Radiographs were obtained 2, 3 and 4 weeks after surgery. Four weeks after surgery, the radiuses were collected and used for biomechanical testing or histological examinations. RESULTS: During the 4 weeks of observation, no adverse effects due to the implants occurred. The radiographic scores in each group did not differ significantly at any time point. The maximum load in the LCP group was significantly higher than that in the TITAN and Fixin groups. There was no significant difference in bending stiffness or work to failure among the groups. Initial fracture healing via woven bone was evident at histological evaluation. CONCLUSIONS: All three miniature locking plate systems provided adequate fracture stabilization 4 weeks after surgery, despite their differences, in rabbit models.

Bone regeneration by calcium phosphate-loaded carboxymethyl cellulose nonwoven sheets in canine femoral condyle defects.

The bone regeneration capacities of calcium phosphate (CaP)-loaded carboxymethyl cellulose (CMC) nonwoven sheet (CMC/CaP) were evaluated using a dog lateral femoral condyle defect model. In addition, the effect of bFGF on bone regeneration when added to CMC/CaP sheet was investigated. The CMC and CMC/CaP sheets have high operability. The new bone formation rate in the CMC/CaP group was significantly higher than that in the control and CMC groups based on micro-computed tomography and histological evaluation. In contrast, there was no significant difference between the CMC/CaP group and the CMC/CaP/f group. In conclusion, the CMC/CaP sheet has the ability to promote new bone formation and seems to be useful as a sheet-shaped bone graft substitute. The effect of the auditioning signaling molecules to the CMC/CaP sheet, such as bFGF, requires further investigation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1516-1521, 2019.

Implantation of tetrapod-shaped granular artificial bones or ß-tricalcium phosphate granules in a canine large bone-defect model.

We investigated biodegradability and new bone formation after implantation of tetrapod-shaped granular artificial bone (Tetrabone®) or ß-tricalcium phosphate granules (ß-TCP) in experimental critical-size defects in dogs, which were created through medial and lateral femoral condyles. The defect was packed with Tetrabone® (Tetrabone group) or ß-TCP (ß-TCP group) or received no implant (control group). Computed tomography (CT) was performed at 0, 4 and 8 weeks after implantation. Micro-CT and histological analysis were conducted to measure the non-osseous tissue rate and the area and distribution of new bone tissue in the defect at 8 weeks after implantation. On CT, ß-TCP was gradually resorbed, while Tetrabone® showed minimal resorption at 8 weeks after implantation. On micro-CT, non-osseous tissue rate of the control group was significantly higher compared with the ß-TCP and Tetrabone groups (P<0.01), and that of the ß-TCP group was significantly higher compared with the Tetrabone group (P<0.05). On histology, area of new bone tissue of the ß-TCP group was significantly greater than those of the Tetrabone and control groups (P<0.05), and new bone distribution of the Tetrabone group was significantly greater than those of the ß-TCP and control groups (P<0.05). These results indicate differences in biodegradability and connectivity of intergranule pore structure between study samples. In conclusion, Tetrabone® may be superior for the repair of large bone defects in dogs.

Bone regeneration by the combined use of tetrapod-shaped calcium phosphate granules with basic fibroblast growth factor-binding ion complex gel in canine segmental radial defects.

The effect of tetrapod-shaped alpha tricalcium phosphate granules (Tetrabones(®) [TB]) in combination with basic fibroblast growth factor (bFGF)-binding ion complex gel (f-IC gel) on bone defect repair was examined. Bilateral segmental defects 20-mm long were created in the radius of 5 dogs, stabilized with a plate and screws and implanted with 1 of the following: TB (TB group), TB and bFGF solution (TB/f group), and TB and f-IC gel (TB/f-IC group). Dogs were euthanized 4 weeks after surgery. Radiographs showed well-placed TB granules in the defects and equal osseous callus formation in all the groups. Histomorphometry revealed that the number of vessels and volume of new bone in the TB/f-IC group were significantly higher than those in the other groups. However, no significant differences in neovascularization and new bone formation were observed between the TB/f and TB groups. Furthermore, no significant difference in the lamellar bone volume or rate of mineral apposition was observed among groups. These results suggest that increased bone formation might have been because of the promotion of neovascularization by the f-IC gel. Therefore, the combinatorial method may provide a suitable scaffold for bone regeneration in large segmental long bone defects.

Changes in bone regeneration by trehalose coating and basic fibroblast growth factor after implantation of tailor-made bone implants in dogs.

In this study, we aimed to determine the effect of trehalose coating and the optimal dose of basic fibroblast growth factor (bFGF), an osteoinductive protein, loaded onto tailor-made bone implants for implant-induced bone formation in vivo. We fabricated tailor-made α-tricalcium phosphate bone implants (11 mm diameter with 2 parallel cylindrical holes). bFGF 0, 1, 10, 100 or 200 µg/implant was incorporated into implants with and without a trehalose coating, and these were subsequently implanted into dogs to correct temporal bone defects of the same size and shape. Four weeks after implantation, we analyzed the bone implants and surrounding tissues by using micro-computed tomography imaging and histological analyses, as well as gross evaluation. No significant difference in new bone formation was observed between implants with and without a trehalose coating at any of the bFGF doses. Bone implants with 100 and 200 µg bFGF showed significantly more new bone formation at the implant site and within the cylindrical holes of the implants than those without bFGF (P<0.05). However, heterotopic bone formation on the skull near the implant was observed in the group that received 200 µg bFGF. These results suggest that 100 µg bFGF is the optimal dose for this implant in dogs, and that the trehalose coating may not be necessary in vivo, probably due to the presence of blood proteins and electrolytes at the implant site.

Cell-sheet technology combined with a thienoindazole derivative small compound TD-198946 for cartilage regeneration.

Articular cartilage is a permanent tissue, with poor self-regenerative capacity. Consequently, a tissue engineering approach to cartilage regenerative therapy could greatly advance the current treatment options for patients with cartilage degeneration and/or defects. A successful tissue engineering approach would require not only induction of chondrogenic differentiation, but also suppression of subsequent endochondral ossification and chondrocyte dedifferentiation. We previously reported that direct injection of the thienoindazole derivative, TD-198946, into the knee joints of mice halted the progression of osteoarthritis; the compound induced chondrogenic differentiation without promoting endochondral ossification. In the present study, we applied TD-198946 to a cell-based cartilage reconstruction model, taking advantage of the cell-sheet technology. Cartilaginous cell-sheets were generated by culturing mouse and canine costal chondrocytes and human mesenchymal stem cells with TD-198946 on temperature-responsive dishes. The transplanted cell-sheets were then successfully used to promote the reconstruction of permanent cartilage, with no evidence of chondrocyte hypertrophy in the knee articular cartilage defects created in mice and canines. Thus, TD-198946 is a promising candidate for cell-based cartilage reconstruction therapies, enabling us to avoid any concern surrounding the use of scaffolds or cytokines to stimulate regeneration.

Repair of rabbit segmental femoral defects by using a combination of tetrapod-shaped calcium phosphate granules and basic fibroblast growth factor-binding ion complex gel.

The effect of tetrapod-shaped alpha tricalcium phosphate granules (TB) as a scaffold combined with basic fibroblast growth factor (bFGF)-binding ion complex gel (f-IC gel) on neovascularization and bone regeneration was evaluated in segmental femoral defects of rabbits. The defects were stabilized using a plate with a polypropylene mesh cage (PMC) containing one of the following: PMC alone (PMC group), TB (TB group), TB and bFGF (TB/f group), TB and IC gel (TB/IC group), or TB and f-IC gel (TB/f-IC group). Four rabbits from each group were euthanized at 2 and 4 weeks after surgery. Histomorphometry showed that the number of vessels and the volume of new bone in the TB/f-IC group were significantly higher than those in the other groups at all time points. There were no differences in the extent of neovascularization and new bone formation between the TB and TB/f groups. These findings suggest that the combination of TB and f-IC gel facilitated both neovascularization and new bone formation in segmental femoral defects of rabbits. This combination may be of considerable use for treating segmental long bone defects.

Development and evaluation of tetrapod-shaped granular artificial bones.

We have developed a novel form of granular artificial bone "Tetrabones" with a homogeneous tetrapod shape and uniform size. Tetrabones are four armed structures that accumulate to form the intergranular pores that allow invasion of cells and blood vessels. In this study we evaluated the physicochemical characteristics of Tetrabones in vitro, and compared their biological and biomechanical properties in vivo to those of conventional ß-tricalcium phosphate (ß-TCP) granule artificial bone. Both the rupture strength and elastic modulus of Tetrabone particles were higher than those of ß-TCP granules in vitro. The connectivity of intergranular pores 100, 300, and 400 µm in size were higher in Tetrabones than in the ß-TCP granules. Tetrabones showed similar osteoconductivity and biomechanical stiffness to ß-TCP at 2 months after implantation in an in vivo study of canine bone defects. These results suggest that Tetrabones may be a good bone graft material in bone reconstruction.