Facilitation of arthroscopic visualization and treatment of meniscal tears using a stifle joint distractor in the dog.

BACKGROUND: Stifle arthroscopy has been described to have high sensitivity and specificity in the evaluation of menisci in dogs, particularly for the medial meniscus. However, the visualization of menisci can be difficult. The use of femoral distractors in human medicine has been described to simplify demanding surgical procedures, such as meniscus transplantation. In veterinary medicine, stifle distraction has been reported to facilitate access to the joint and visualization of intra-articular structures, but there are no studies reporting the use of a stifle distraction technique while performing challenging surgical procedures, such as meniscal suture, in clinical patients. The objective of this study was to evaluate the feasibility, effectiveness and safety of stifle distraction to achieve consistent visualization of menisci and to facilitate performing arthroscopic procedures in clinical patients with stifle disease. Initial arthroscopic evaluation of the stifle joint was performed without distraction in the study population consisting of 13 dogs with naturally occurring stifle disease. The criteria for inclusion was prospectively set as the observation of a frank disease or anomaly of the menisci that could not be further treated or clarified without the risk of damaging the joint cartilage due to the requested manoeuvres. After the first examination, distraction was applied in order to complete the assessment of menisci. After achieving an accurate diagnosis, partial meniscectomy or meniscal repair was performed as needed while maintaining the distraction. RESULTS: Complete visualization and assessment of menisci were achieved thanks to the use of distraction. This manoeuvre facilitated access to the required area of the involved meniscus, and meniscal treatment could be successfully performed without damaging the articular cartilage. During the follow-up period, no postoperative complication related to the distraction or to the arthroscopic procedure was observed. CONCLUSIONS: Stifle joint distraction during arthroscopy in dogs improves visualization of both menisci, and particularly the caudal horn of the medial meniscus. Despite being a subjective assessment, it is the authors' opinion that this procedure also increases the ease of performing challenging procedures like meniscal suture, as it enlarges the space available to reach the correct working angulations.

Evaluation of sixty-eight cases of fracture stabilisation by external hybrid fixation and a proposal for hybrid construct classification.

BACKGROUND: Hybrid external fixation (HEF) is an emerging technique for fracture stabilization in veterinary orthopedics, but its use has been reported in few papers in the veterinary literature. The linear and circular elements that form hybrid fixators can be connected in a very high number of combinations, and for this reason just referring to HEF without any classification is often misleading about the actual frame structure. The aim of this study was to retrospectively evaluate fracture stabilization by HEF in 58 client-owned dogs and 8 cats, and to extend the already existing classification for hybrid constructs to include all frame configurations used in this study and potentially applicable in clinical settings. Animal signalment, fracture classification, surgical procedure and frame configuration were recorded. Complications, radiographic, functional and cosmetic results were evaluated at the time of fixator removal. RESULTS: Sixty-eight fractures in 58 dogs and eight cats were evaluated. Two dogs had bilateral fractures. Fifty-one percent were radio-ulna, 34% tibial, 9% humeral, 3% femoral and 3% scapular fractures. One ring combined with one or two linear elements was the most widely employed configuration in this case series. Radiographic results at the time of frame removal were excellent in 59% of the cases, good in 38% and fair in 3%, while functional and cosmetic results were excellent in 69% of the cases, good in 27% and fair in 4%. CONCLUSIONS: HEF is a useful option for fracture treatment in dogs and cats, particularly for peri and juxta-articular fractures. It can be applied with a minimally invasive approach, allows adjustments during the postoperative period and is a versatile system because of the large variety of combinations that can fit with the specific fracture features. The classification used enables to determine the number of linear and circular elements used in the frame.

A Bilateral Acetabular Physeal Fracture Treated with External Fixation in an Immature Cat.

This study aimed to assess the outcome of a bilateral acetabular physeal fracture treated with external fixation in an immature cat, a surgical technique not usually employed in immature patients. The fixator took 40 days, and it was removed after radiographic bone healing was achieved. No significant complications related to the technique were identified, and the outcome was classified as good based on the functional assessment and pain scales employed. The use of external fixation for stabilising acetabular fractures in immature cats should be considered a viable technical option, especially for minimally invasive stabilisation.

Effects of rotation and osteotomy angulation on patellar tendon insertion position during circular tibial tuberosity osteotomy.

OBJECTIVE: To evaluate the influence of rotation of the tibial tuberosity (TT) in the sagittal plane and angulation of osteotomy in the frontal plane (FPA) on the displacement of patellar tendon (PT) insertion. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: Canine tibiae (n = 36). METHODS: Nine groups of 4 tibiae each had a circular osteotomy of the TT at an FPA from -20° to +20° with increments of 5° for each group. The osteotomized TT was rotated by angles of rotation (AORs) of 10°, 20°, or 30° in the sagittal plane. The craniocaudal (CCD), distoproximal (DPD), and mediolateral (MLD) displacements of a marker located at the PT insertion on the TT were evaluated radiographically. Differences between groups were analyzed by Mann-Whitney U test and Friedman 2-way ANOVA. RESULTS: There was a significant correlation between the AOR and CCD. A positive FPA resulted in a high CCD and lateral shift of the TT at every AOR. Performing an osteotomy at an FPA of 0° produced the maximum amount of DPD. CONCLUSIONS: FPA and AOR during circular osteotomy of the TT influence the final displacement of the PT insertion in all 3 planes.

External Fixation for Fracture Stabilization of the Sacrum in 15 Dogs.

This study aimed to evaluate the feasibility, complications, and outcomes of external fixation (EF) for the treatment of sacral fractures in dogs, either as a primary fixation system or as a complementary technique. A total of 15 dogs with sacral fractures were surgically treated using different EF configurations, either as primary or secondary stabilization. The results were evaluated for the extent of fracture reduction, stability during treatment, complications, and bone healing. In most cases, the outcomes were excellent in terms of bone healing, neurological conditions, and pain assessment. The mean bone healing time was 9.45 ± 5.66 weeks. One (6.66%) patient presented a complication due to the technique. In conclusion, the use of EF should be considered for the stabilization of sacral fractures because of its minimal invasiveness, stability, and ease of application.

Retrospective Assessment of Thirty-Two Cases of Pelvic Fractures Stabilized by External Fixation in Dogs and Classification Proposal.

The goals of this study were to evaluate the outcomes of bone healing, patient comfort during the treatment, functional results, and complications in pelvic fractures treated with external fixation, as well as to propose a classification system for the applied external frames. A total of thirty-two canine patients with pelvic fractures of different origins were treated. To provide a better reference for the frames used, an alphanumeric classification system was developed, detailing the frame structure and the number and location of the pins used. In this study, eighty-six fractures were treated in the 32 patients of this work, with an average fixation time of 9.88 ± 4.15 weeks. No major complications were detected in this case cohort, and the outcomes were rated at 9.46 based on a visual assessment scale for the patient's comfort during treatment. Outcomes graded as excellent and good were 96%. The use of external fixation for stabilization of pelvic fractures should be considered as a technical option, especially for minimally invasive stabilization of complex fractures, either as a primary or secondary stabilization.

Comparison between Areas of Bone Visualization Using Radiolucent Hybrid Fixator Frames and Graphically Simulated Metallic Frames: An Ex Vivo Study.

The objective of this study is to evaluate the difference between the amount of bone visible with the superimposition of a radiolucent hybrid external fixator and a graphically simulated metallic frame. Eighteen frames were applied to eighteen bone specimens. The fracture area (FA), the radiolucent area (RLA) and the radiopaque area (ROA) inside the FA were calculated for each construct on both postoperative views. The ratio between the RLA and FA and between the ROA and FA was used to evaluate the amount of bone visible in the FA with a radiolucent and a radiopaque fixator, respectively. Finally, the areas of RLA and ROA were compared using the Wilcoxon test and Friedman test to evaluate the effect of the radiolucent material on the amount of bone visible. Differences were considered significant if p < 0.5. In every specimen p was <0.5. The amount of bone visible was significantly higher with the radiolucent frame compared to the radiopaque frame. Based on the results of this study, the use of radiolucent materials can be a valuable option for external fixation, in order to decrease the radiographic interference of the frame, allowing better assessment of fracture reduction and bone healing on postoperative radiographs.

Minimally Invasive Osteosynthesis Techniques for Humerus Fractures.

A thorough knowledge of humeral anatomy is critical to performing minimally invasive techniques. Fluoroscopy, when available, is invaluable in optimizing fracture repair with minimally invasive techniques. Minimally invasive approaches decrease morbidity and allow an earlier return to function. Minimally invasive fracture repair is performed using implant systems similar to open approaches.

Minimally Invasive Plate Osteosynthesis Fracture Reduction Techniques in Small Animals.

Indirect fracture reduction is used to align diaphyseal fractures when using minimally invasive fracture repair. Indirect reduction achieves functional fracture reduction without opening the fracture site. The limb is restored to length and spatial alignment is achieved to ensure proper angular and rotational alignment. Fracture reduction can be accomplished using a variety of techniques and devices, including hanging the limb, manual traction, distraction table, external fixators, and fracture distractors.

Acute lameness in a cat with disseminated mycobacteriosis.

Mycobacterium avium infection was diagnosed in an adult cat showing acute lameness of the right hind limb, enlargement of the right popliteal lymph node and two cutaneous nodular lesions of the right chest wall. Conventional radiography of the proximal tibia showed a proliferative osteolytic lesion. Cytological examination of the right popliteal lymph node and the nodular skin lesions fine needle aspiration smears, demonstrated granulomatous inflammation with many negative staining bacilli within macrophages or in smears background. The diagnosis was confirmed by Ziehl­Neelsen staining of the smears and the identification of mycobacteria was performed by microbiological and molecular methods. Histopathology performed after the necropsy revealed disseminated mycobacteriosis with granulomatous mesenteric lymphadenitis, granulomatous pneumonia, hepatitis and tibial osteomyelitis. M. avium is a well­known agent of gastro­enteric, respiratory or disseminated disease in immunocompromised cats but there are few cases reported in literature of bone involvement in systemic mycobacteriosis.

Real-time detection of the mutation responsible for progressive rod-cone degeneration in Labrador Retriever dogs using locked nucleic acid TaqMan probes.

Progressive rod-cone degeneration (prcd) is a late onset, autosomal recessive, inherited disease in dogs caused by a G > A substitution in the PRCD locus. prcd has been reported in more than 18 breeds, including Labrador Retriever dogs. In this study, a real-time polymerase chain reaction (PCR) assay, exploiting the features of locked nucleic acid (LNA) fluorescent-labeled probes, was developed to genotype the sequence variants responsible for the disease. Two Labrador Retrievers were diagnosed with prcd by ophthalmological examination performed by a panelist of the Italian hereditary eye disease control program. The 2 dogs, as well as 8 related and 14 unrelated Labrador Retrievers, were genotyped with both direct sequencing of the disease locus and real-time LNA TaqMan PCR assay. Even though the region surrounding the mutation was predicted to be highly structured, making probe annealing difficult, the real-time PCR assay allowed researchers to correctly genotype the dogs in all cases with a sensitivity threshold of 4 ng/reaction of genomic DNA. A real-time PCR assay will allow a high-throughput analysis of a larger cohort of dogs, thereby enabling researchers to investigate the prevalence of the mutated allele in the affected breeds.

Minimally invasive plate osteosynthesis fracture reduction techniques in small animals.

Indirect fracture reduction is used to align diaphyseal fractures in small animals when using minimally-invasive fracture repair. Indirect reduction achieves functional fracture reduction without opening the fracture site. The limb is restored to length and spatial alignment is achieved to ensure proper angular and rotational alignment. Fracture reduction can be accomplished using a variety of techniques and devices, including hanging the limb, manual traction, distraction table, external fixators, and a fracture distractor.

Early detection and treatment of screw loosening in triple pelvic osteotomy.

OBJECTIVE: To detect early screw loosening in triple pelvic osteotomy (TPO) and to evaluate the efficacy of retightening using fluoroscopic guidance and minimally invasive surgery to maintain acetabular alignment and achieve bone healing. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Sixteen dogs that had TPO. METHODS: Dogs (16) had TPO (21) by using pre-angled plates secured with 3.5 and 4.0 mm screws, with ischiatic or iliac cerclage, for osteosynthesis. In all but 1 TPO at least 1 screw was inserted into the sacral body (43 screws). The mean radiographic screw length inserted in the sacrum was 10.2 mm, and the mean percent sacral engagement was 22%. Dogs were examined clinically and radiographically immediately postoperatively, and at 10, 30, 60, and 90 days to evaluate screw position. Loose screws were retightened through stab incisions using fluoroscopy to locate the screw. RESULTS: TPO was performed without operative complications. At 10 days, 12 TPOs (57%; 11 dogs) had loose screws primarily located in the cranial aspect of the plate. This represented 20% (25) of the inserted screws. In 5 dogs, screw loosening resulted in medial rotation of the acetabular segment. All loose screws were retightened; 3 screws loosened again in 2 dogs and were detected at 60 days. However, the osteotomies healed with the planned acetabular rotation without further intervention. Screw tightening corrected the acetabular segment displacement. Screws correctly seated at 10 days did not subsequently loosen. Clinical and radiographic outcome was judged excellent in all dogs. CONCLUSION: Loose screws in TPO plates can be identified by 10 days postoperatively and retightened using fluoroscopic guidance to achieve acetabular realignment and healing without need for further surgery. CLINICAL RELEVANCE: Postoperative radiographic evaluation of screw position at 10 days after TPO is recommended to detect loose screws. Retightening loose screws should be considered as an alternative to TPO revision or confinement, especially in immature dogs.

Limb sparing using a double bone-transport technique for treatment of a distal tibial osteosarcoma in a dog.

OBJECTIVE: To evaluate the treatment of a spontaneously occurring osteosarcoma in a dog by means of tumor resection and bone regeneration of a 12-cm defect using double bone transport. STUDY DESIGN: Case report. ANIMALS OR SAMPLE POPULATION: An 11 year-old client-owned German shepherd. METHODS: After tumor resection, a preassambled Ilizarov frame was secured to the proximal tibia and to the tarso-metatarsal region. Two osteotomies were performed in the proximal metaphysis. The two bone segments were transfixed with 1.5-mm-diameter wires, each secured to a ring, and bone transport was performed until the distal segment reached the talar surface. Cisplatin was administered 14, 35, and 59 days after surgery. RESULTS: Bone regenerate was first visible radiographically 4 weeks after surgery. The frame was removed 162 days after surgery. The hock was protected with a plaster cast because the tarsal arthrodesis was not complete. The dog underwent tibiotarsal arthrodesis 201 days after osteosarcoma resection. The dog died of metastatic disease 239 days after the initial surgery. CONCLUSIONS: Even though this dog died of systemic metastases, local recurrence did not develop. Cisplatin chemotherapy did not appear to negatively affect bone regeneration. CLINICAL RELEVANCE: To our knowledge, the double transport technique has not been previously described in the veterinary literature. In this dog, this technique decreased the duration of treatment compared with a conventional single-segment transport technique.

Are circular external fixators weakened by the use of hemispheric washers?

OBJECTIVES: To compare the axial mechanical stability of 3 circular external fixators systems with and without hemispheric washers. STUDY DESIGN: Experimental study. METHODS: The axial stiffness and load necessary to produce 0.5 and 1 mm of displacement of 10 circular external fixator constructs from 3 manufacturers were tested on a materials testing machine. The constructs tested included the Small Bone fixator (SBF; Hofmann S.a.S., Monza, Italy), the IMEX ring fixator (IMEX Inc., Longview, TX), and the Multiplanar C-Fix (MCF; PanVet Distribuzione, Seriate, Italy). Five configurations were tested for each construct: (1) conventional nut fixation, (2) hemispheric washer fixation with connecting rods offset by 0, (3) 1, and (4) 2 holes, and (5) with a ring placed at maximum angulation. RESULTS: The loads resisted at 0.5 and 1 mm of displacement did not differ when frame configurations were compared (P =.25733 and.33769, respectively). The linear stiffness of the following configurations were decreasingly stiff: standard constructs, hemispheric washers with connecting rods perpendicular to rings, hemispheric washers with connecting rods offset by 1 hole, hemispheric washers with connecting rods offset by 2 holes, and ring offset in relation to bone model. The SBF constructs tested were 34% and 41% more rigid than the IMEX and MCF constructs tested despite the larger diameter of the connecting rods for the IMEX frames (6 mm) compared with the SBF frames (5 mm). The IMEX constructs tested were 6% more rigid than the MCF constructs tested. CONCLUSIONS: Adding hemispheric washers and angling connecting rods in relation to rings did not influence the loads resisted at 0.5 and 1 mm displacement but decreased construct stiffness. CLINICAL RELEVANCE: The use of hemispheric washers had minor effects on the biomechanical performance of fixator frames tested in this study when used to angle a ring in relation to connecting rods for circular external fixators.