Comparison of three-dimensional printed patient-specific guides versus freehand approach for radial osteotomies in normal dogs: Ex vivo model.

OBJECTIVE: To compare the accuracy of three-dimensional (3D) printed patient-specific guide (PSG) with a freehand (FH) approach for radial osteotomies in ex vivo normal dogs. STUDY DESIGN: Experimental study. ANIMALS: Twenty four ex vivo thoracic limb pairs from normal beagle dogs. METHODS: Computed tomography (CT) images were collected preoperatively and postoperatively. Three osteotomies tested (n = 8/group) were: (1) uniplanar 30° frontal plane wedge ostectomy, (2) oblique plane (30° frontal, 15° sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30° frontal, 15° sagittal, and 30° external). Limb pairs were randomized to a 3D PSG or FH approach. The resultant osteotomies were compared with virtual target osteotomies by surface shape-matching postoperative to the preoperative radii. RESULTS: The mean ± standard deviation osteotomy angle deviation for all 3D PSG osteotomies (2.8 ± 2.8°, range 0.11-14.1°) was less than for the FH osteotomies (6.4 ± 6.0°, range 0.03-29.7°). No differences were found for osteotomy location in any group. In total, 84% of 3D PSG osteotomies were within 5° deviance from the target compared to 50% of freehand osteotomies. CONCLUSION: Three-dimensional PSG improved FH accuracy of osteotomy angle in select planes and the most complex osteotomy orientation in a normal ex vivo radial model. CLINICAL SIGNIFICANCE: Three-dimensional PSGs provided more consistent accuracy, which was most notable in complex radial osteotomies. Future work is needed to investigate guided osteotomies in dogs with antebrachial bone deformities.

Accuracy of pin placement in the canine thoracolumbar spine using a free-hand probing technique versus 3D-printed patient-specific drill guides: An ex-vivo study.

OBJECTIVE: To compare pin placement accuracy, intraoperative technique deviations, and duration of pin placement for pins placed by free-hand probing (FHP) or 3D-printed drill guide (3DPG) technique. SAMPLE POPULATION: Four greyhound cadavers. METHODS: Computed tomography (CT) examinations from T6-sacrum were obtained for determination of optimal pin placement and 3DPG creation. Two 3.2/2.4-mm positive profile pins were inserted per vertebra, one left and one right from T7-L7 (FHP [n = 56]; 3DPG [n = 56]) by one surgeon and removed for repeat CT. Duration of pin placement and intraoperative deviations (unanticipated deviations from planned technique) were recorded. Pin tracts were graded by two blinded observers using modified Zdichavsky classification. Descriptive statistics were used. RESULTS: A total of 54/56 pins placed with 3DPGs were assigned grade I (optimal placement) compared with 49/56 pins using the FHP technique. A total of 2/56 pins placed with 3DPGs and 3/56 pins using the FHP technique were assigned grade IIa (partial medial violation). A total of 4/56 pins placed using the FHP technique were assigned grade IIIa (partial lateral violation). No pins were assigned grade IIb (full medial violation). Intraoperative technique deviations occurred with 6/56 pins placed using the FHP technique and no pins with 3DPGs. Overall, pins were placed faster (mean ± SD 2.6 [1.3] vs. 4.5 [1.8] min) with 3DPGs. CONCLUSIONS: Both techniques were accurate for placement of spinal fixation pins. The 3DPG technique may decrease intraoperative deviations and duration of pin placement. CLINICAL RELEVANCE: Both techniques allow accurate pin placement in the canine thoracolumbar spine. The FHP technique requires specific training and has learning curve, whereas 3DPG technique requires specific software and 3D printers.

Comparison of two postoperative complication grading systems after treatment of stifle and shoulder instability in 68 dogs.

OBJECTIVE: (1) To adapt and apply the Clavien-Dindo (aCD) postoperative complication grading system to dogs experiencing complications following a single orthopedic procedure. (2) To compare the reliability of the Clavien-Dindo system to the Cook complication grading system. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Sixty-eight client-owned dogs. METHODS: Scenarios derived from complications following TightRope stabilization of the stifle and shoulder were graded by four ACVS-boarded surgeons using two systems; the Cook 3-point scale and the aCD 5-point scale. Because the aCD system distinguishes complications from outcomes ("sequelae" or "failure to cure"), two data sets were created: one with (n = 76) and without (n = 67) inclusion of "sequelae" and "failure to cure" cases. Interobserver reliability was evaluated using intraclass correlation coefficient (ICC) calculations. RESULTS: Seventy-six scenarios from 68 records were evaluated. The ICC of the aCD system was 0.620 consistent with moderate reliability. The reliability of the Cook system was good, with an ICC of 0.848. Exclusion of cases with "sequelae" or "failure to cure" resulted in excellent reliability of the aCD system (ICC = 0.975) and good reliability of the Cook systems (ICC = 0.857). CONCLUSION: The aCD grading system was less reliable than the Cook system when evaluating all cases but more reliable when evaluating cases of complications excluding "sequelae" and "failures to cure". CLINICAL SIGNIFICANCE: The Cook grading system is reliably good in grading postoperative complications in dogs. The aCD system can also be used to assess postoperative complications with excellent reliability but is less reliable when distinguishing complications from other postoperative outcomes.

Virtual surgical planning and 3D printing: Methodology and applications in veterinary oromaxillofacial surgery.

Virtual surgical planning is the process of planning and rehearsing a surgical procedure completely within the virtual environment on computer models. Virtual surgical planning and 3D printing is gaining popularity in veterinary oromaxillofacial surgery and are viable tools for the most basic to the most complex cases. These techniques can provide the surgeon with improved visualization and, thus, understanding of the patients' 3D anatomy. Virtual surgical planning is feasible in a clinical setting and may decrease surgical time and increase surgical accuracy. For example, pre-operative implant contouring on a 3D-printed model can save time during surgery; 3D-printed patient-specific implants and surgical guides help maintain normocclusion after mandibular reconstruction; and the presence of a haptic model in the operating room can improve surgical precision and safety. However, significant time and financial resources may need to be allocated for planning and production of surgical guides and implants. The objectives of this manuscript are to provide a description of the methods involved in virtual surgical planning and 3D printing as they apply to veterinary oromaxillofacial surgery and to highlight these concepts with the strategic use of examples. In addition, the advantages and disadvantages of the methods as well as the required software and equipment will be discussed.

Transarticular elastic external skeletal fixator correction of a stifle rotational deformity and patellar luxation in a dog.

OBJECTIVE: To report the preoperative evaluation, treatment with transarticular elastic external skeletal fixation (ESF), and outcome of a dog with bilateral medial patellar luxation (MPL) and stifle rotational deformity. ANIMAL: One nonambulatory, 2.5-month-old, 7.5-kg mixed-breed intact female dog. STUDY DESIGN: Case report METHODS: Complex pelvic limb deformities were assessed with physical examination and computed tomography (CT) and characterized as bilateral grade 4 MPL and 90° internal rotation of the tibia in relation to the femur. Three-dimensional imaging and bone models were used to quantify the deformity and rehearse surgical correction. Transarticular elastic chains between ESF pins in the femur and tibia were used to gradually correct stifle rotational malalignment on each pelvic limb. Soft tissue releases, imbrication, and a transphyseal staple were used to correct the patellar luxation (PL) and femoral varus. The dog was reevaluated for 1 year postoperatively. RESULTS: Short- and long-term management included intensive physical rehabilitation to increase pelvic limb strength and function. Surgical treatment resulted in resolution of the PL and neutral stifle alignment. The dog was able to ambulate with persistent decreased range of motion of the stifle. CONCLUSION: Transarticular elastic chains and femoral physeal stapling improved the function of a dog with severe bone deformities and PL in a growing dog.

Accuracy and safety of three-dimensionally printed animal-specific drill guides for thoracolumbar vertebral column instrumentation in dogs: Bilateral and unilateral designs.

OBJECTIVE: To evaluate the safety and accuracy of a unilateral three-dimensionally printed animal-specific drill guide (3DASDG) design for unilateral stabilization in the thoracolumbar vertebral column of dogs compared to a bilateral design. STUDY DESIGN: Cadaveric study. SAMPLE POPULATION: Fifty-two corridors in one canine cadaver. METHODS: Two 3DASDG designs with 2 drilling tubes each were created from T8 to L7 vertebrae. Fifty-two corridors were drilled on the right and the left sides by using unilateral and bilateral designs, respectively. Planned and postoperative trajectories (entry point, exit point, angle) were compared to establish the accuracy. Statistical analysis was used for accuracy comparison between designs. Safety was evaluated by using Zdichavsky classification. RESULTS: Unilateral and bilateral drill guide designs were not different for entry point and angle deviations; however, they were different for the exit point deviations. Two corridors breached outside the vertebra. For all guides, mean entry and exit point deviations were less than 1 and 2 mm, respectively. The maximum entry or exit point deviation in both groups was 4.7 mm. The mean angle deviation was <3.5°, and the maximum angle deviation was 9.3°. CONCLUSION: No difference was detected in accuracy of entry points and angle deviations between drill guide designs tested in normal vertebrae. The technique was classified as highly safe. CLINICAL SIGNIFICANCE: A unilateral drill guide design may be a safe alternative to bilateral guides for unilateral stabilization of the thoracolumbar vertebral column in dogs.

A computed tomographic graphical approach to guide correction of femoral torsion.

OBJECTIVE: To report geometric methods to assess femoral transverse bone morphology and develop a virtual method to guide the surgical correction of femoral torsional deformities. STUDY DESIGN: Observational study. SAMPLE POPULATION: Sixteen client-owned dogs comprising 14 normal femurs and 14 femurs with angulation-rotation bone deformities. METHODS: Femoral torsion angle was measured with computed tomographic (CT) three-dimensional (3D) multiplanar reconstruction. Distal femoral transverse morphology was estimated with geometric methods and compared to direct measurements to span a target 20° angle on 3D reconstructions. A virtual correction of 20° was performed, and 3D-printed bone models were created. Femoral torsion of corrected bone models was compared to precorrection. RESULTS: Geometric estimates with an arc and chord of the metaphyseal area and chord of a best fit circle did not differ from direct measurement of femoral cortical length along the cranial cortex. Femoral torsion differed between normal femurs (25.8° ± 6°) and those with deformity (36.9° ± 8.4°, P < .001). Torsion that was measured on corrected 3D bone models did not differ from the expected torsion (preoperative +20°). CONCLUSION: Geometric methods provided an accurate estimate of distal femoral transverse bone morphology. Rotation of the distal femur based on geometric methods resulted in an accurate correction of torsion. CLINICAL SIGNIFICANCE: Femoral bone diameter can be measured on a CT cross-section, and rotation distance can be calculated to achieve a desired correction of torsion. This approach provides a simple and accurate method to guide the correction of femoral torsion.

Recommendations for rehabilitation after surgical treatment of cranial cruciate ligament disease in dogs: A 2017 survey of veterinary practitioners.

OBJECTIVE: To report current recommendations made by veterinarians for rehabilitation after surgical treatment of cranial cruciate ligament (CrCL) disease. STUDY DESIGN: Anonymized electronic survey. SAMPLE POPULATION: Veterinarians performing CrCL stabilization. METHODS: An electronic survey was created to collect information on general attitudes toward postoperative rehabilitation and recommendations regarding therapeutic modalities and bandaging. Quantitative data are reported by descriptive statistical analysis, percentage of responses, or mean (±SD). The recommendations for postoperative bandaging beyond 24 hours and for postoperative rehabilitation after extracapsular stabilization compared with after tibial osteotomy were tested by using Cochran-Mantel-Haenszel tests, with P < .05 considered statistically significant. RESULTS: The data analysis included 376 responses (13% response rate). Most (71%) respondents consistently recommended postoperative rehabilitation. Rehabilitation was more than twofold more likely to be recommended after extracapsular stabilization than after osteotomies (P = .0142). Most respondents did not recommend bandaging beyond 24 hours postoperatively (P = .00012). CONCLUSION: Most respondents recommended either formal or informal postoperative rehabilitation therapy. CLINICAL SIGNIFICANCE: If the survey respondents are representative of veterinarians performing CrCL surgery, the current attitude is supportive of postsurgical rehabilitation. Most respondents would welcome evidence-based guidelines for rehabilitation protocols.

An Interdisciplinary Approach to Surgical Skills Training Decreases Programmatic Costs.

BACKGROUND: Surgical resident duty hour limitations have necessitated operative skill training outside of the operating room. Although wet-lab skills training is ideal, materials and human resource requirements make wet labs-utilizing biologic samples cost prohibitive for many residency programs. To resolve this problem, our general surgery residency program collaborated with the Institution's School of Veterinary Medicine Surgery Residency program to pilot a cost-effective interdisciplinary surgical skills curriculum. MATERIALS AND METHODS: The general surgery residency program manager and program director initiated a collaboration with the Veterinary Surgery Residency. Postgraduate year (PGY) 2 general surgery residents and PGY 1-3 veterinary surgery residents participated in monthly joint surgical skills practice sessions. A novel interdisciplinary surgical skills curriculum was implemented that incorporated skills beneficial to both sets of trainees utilizing donated canine cadavers. RESULTS: A total of nine joint skills sessions were conducted for nine general surgery residents and five veterinary surgery residents. A cost analysis was conducted for a surgical skills curriculum servicing both programs independently and compared to the actual costs of the collaborative curriculum. The cost analysis estimated total savings generated by the collaborative to be $27,323.79. Review of initial feedback from trainees suggest that skill sessions reinforce knowledge, and that the collaborative skills sessions were an enjoyable and valuable learning activity. CONCLUSIONS: The skills curriculum collaborative has proven to be a cost-effective and high quality interdisciplinary pedagogic tool. The partnership allowed for mutually beneficial resource sharing and allowed for the initiation of a surgical skills wet lab that had previously been unavailable to both groups.

Teaching and proficiency assessment for arthroscopy in veterinary surgery: A 2017 survey of diplomates and residents of the American and European College of Veterinary Surgeons.

OBJECTIVE: To determine current methods of arthroscopic skills training and proficiency assessment, identify skills considered fundamental to arthroscopy, and evaluate desire for a formal training and assessment program. STUDY DESIGN: Anonymized electronic survey. SAMPLE POPULATION: Diplomates and residents of the American College of Veterinary Surgeons (ACVS) and European College of Veterinary Surgeons (ECVS). METHODS: An electronic survey was distributed in commercial software (Qualtrics, Provo, Utah). Questions were divided into 4 categories: (1) demographics, (2) arthroscopy experience, (3) teaching, and (4) proficiency assessment. Descriptive statistical analysis was performed. Comparisons between groups were performed by using χ2 , t tests, and 1-way ANOVA (P ≤ .05). RESULTS: In total, 429 diplomates and 149 residents responded (response rate 28%). Overall, 80% of respondents trained using clinical cases. Barriers to simulator training included cadaver/simulator availability and time. Skills deemed most fundamental included anatomic knowledge, precise portal placement, triangulation, and image orientation. Overall, 90% of respondents supported a formal training program with requirement to demonstrate proficiency; 80% believed this should be part of standard ACVS/ECVS residency training. CONCLUSION: Arthroscopic skills are taught by using clinical cases, with subjective proficiency assessment. Fundamental skills are those that may be taught using simulators. There is enthusiasm for formal arthroscopic skills training and assessment. CLINICAL SIGNIFICANCE: Improved acquisition and assessment of fundamental arthroscopic skills is indicated. A validated methodology for formal training using simulators, minimizing morbidity, and facilitating objective evaluation is warranted. This is the first phase of a project to develop and validate a simulator program.

Assessment of overall thoracic limb axial alignment in dogs with antebrachial deformity.

OBJECTIVE: To assess overall thoracic limb axial alignment in dogs with and without angular limb deformity (ALD). STUDY DESIGN: Ex vivo and retrospective observational clinical study. ANIMALS: Forty canine thoracic limbs from bilateral normal specimens (10 pairs) and unilateral antebrachial ALD (10 uniapical and 10 biapical deformities). METHODS: Computed tomography images of the entire thoracic limb were collected for multiplanar reconstruction. Baseline limb axis was defined by the humeral anatomic axis. Axial alignment of the distal humerus, proximal and distal radius, and metacarpal bones were obtained and compared among levels and groups. RESULTS: The mean overall thoracic limb rotation of normal dogs was 35.4 ° (95% CI, 27.2 °, 43.6 °). Mean overall limb rotation in uniapical and biapical deformity was 41.6 ° (95% CI, 33.0 °, 50.1 °) and 54.4 ° (95% CI, 45.8 °, 62.9 °), respectively, but was not statistically different (P = .096). Only overall limb rotation in limbs with biapical ALD was different from normal limbs (P = .008). Rotation at the level of the elbow was 77% and 85% of overall limb rotation in normal and deformity limbs, respectively, and was increased from normal in limbs with ALD (both P < .05). Radial torsion did not differ among groups but was moderately correlated with overall limb rotation. CONCLUSION: Rotation arising in the elbow of limbs with ALD was higher than in normal limbs and accounted for the greatest contribution of overall limb rotation. CLINICAL SIGNIFICANCE: Assessment of radial torsion alone is insufficient to understand overall limb axial alignment in dogs with antebrachial bone deformity.

Application of computed tomography and stereolithography to correct a complex angular and torsional limb deformity in a donkey.

OBJECTIVE: To report the evaluation, surgical planning, and outcome for correction of a complex limb deformity in the tibia of a donkey using computed tomographic (CT) imaging and a 3D bone model. STUDY DESIGN: Case report. ANIMALS: A 1.5-year-old, 110 kg donkey colt with an angular and torsional deformity of the right pelvic limb. METHODS: Findings on physical examimation included a severe, complex deformity of the right pelvic limb that substantially impeded ambulation. Both hind limbs were imaged via CT, and imaging software was used to characterize the bone deformity. A custom stereolithographic bone model was printed for preoperative planning and rehersal of the surgery. A closing wedge ostectomy with de-rotation of the tibia was stabilized with 2 precontoured 3.5-mm locking compression plates. Clinical follow-up was available for 3.5 years postoperatively. RESULTS: CT allowed characterization of the angular and torsional bone deformity of the right tibia. A custom bone model facilitated surgical planning and rehearsal of the procedure. Tibial corrective ostectomy was performed without complication. Postoperative management included physical rehabilitation to help restore muscular function and pelvic limb mechanics. Short-term and long-term follow-up confirmed bone healing and excellent clinical function. CONCLUSION: CT imaging and stereolithography facilitated the evaluation and surgical planning of a complex limb deformity. This combination of techniques may improve the accuracy of the surgeons' evaluation of complex bone deformities in large animals, shorten operating times, and improve outcomes.

Radiographic and magnetic resonance imaging predicts severity of cruciate ligament fiber damage and synovitis in dogs with cranial cruciate ligament rupture.

Cruciate ligament rupture (CR) and associated osteoarthritis (OA) is a common condition in dogs. Dogs frequently develop a second contralateral CR. This study tested the hypothesis that the degree of stifle synovitis and cranial cruciate ligament (CrCL) matrix damage in dogs with CR is correlated with non-invasive diagnostic tests, including magnetic resonance (MR) imaging. We conducted a prospective cohort study of 29 client-owned dogs with an unstable stifle due to complete CR and stable contralateral stifle with partial CR. We evaluated correlation of stifle synovitis and CrCL fiber damage with diagnostic tests including bilateral stifle radiographs, 3.0 Tesla MR imaging, and bilateral stifle arthroscopy. Histologic grading and immunohistochemical staining for CD3+ T lymphocytes, TRAP+ activated macrophages and Factor VIII+ blood vessels in bilateral stifle synovial biopsies were also performed. Serum and synovial fluid concentrations of C-reactive protein (CRP) and carboxy-terminal telopeptide of type I collagen (ICTP), and synovial total nucleated cell count were determined. Synovitis was increased in complete CR stifles relative to partial CR stifles (P<0.0001), although total nucleated cell count in synovial fluid was increased in partial CR stifles (P<0.01). In partial CR stifles, we found that 3D Fast Spin Echo Cube CrCL signal intensity was correlated with histologic synovitis (SR = 0.50, P<0.01) and that radiographic OA was correlated with CrCL fiber damage assessed arthroscopically (SR = 0.61, P<0.001). Taken together, results of this study show that clinical diagnostic tests predict severity of stifle synovitis and cruciate ligament matrix damage in stable partial CR stifles. These data support use of client-owned dogs with unilateral complete CR and contralateral partial CR as a clinical trial model for investigation of disease-modifying therapy for partial CR.

Outcome and complications in dogs with appendicular primary bone tumors treated with stereotactic radiotherapy and concurrent surgical stabilization.

OBJECTIVE: To document the outcome of dogs with appendicular primary bone tumors treated with stereotactic radiotherapy (SRT) and concurrent stabilization. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Eighteen dogs with presumptive or definitive diagnosis of appendicular osteosarcoma. METHODS: Medical records of dogs with appendicular primary bone tumors treated with SRT and stabilization were reviewed for signalment, preoperative staging and diagnostics, radiation dose, stabilization method, and outcome. RESULTS: The distal radius was affected in 13/18 cases. Osteosarcoma or sarcoma was confirmed cytologically or histologically in 15/18 cases. Seven dogs were diagnosed with a pathological fracture at the time of treatment, and 11 were considered at high risk for pathological fracture. Dogs received a single dose (n = 5) or 3 doses (n = 13) of SRT. Surgical stabilization was performed under the same anesthetic event as the final dose of SRT in 10 dogs. Stabilization was achieved with a bone plate (n = 15) or interlocking nail (n = 3). Seventeen dogs received adjuvant chemotherapy. Complications occurred in 16/17 dogs, 15/17 of those being considered major complications. Four dogs experienced more than one complication. Infection was the most common complication, diagnosed in 15/17 cases, and considered as a major complication in 13/15 cases. Postoperative fracture was recorded as a major complication in 3 cases. Nine dogs were amputated at a median of 152 days. The median survival time was 344 days. CONCLUSION: Treatment of bone tumors with SRT and concurrent stabilization was associated with a prohibitively high complication rate in dogs. Alternative methods for limb salvage should be considered for dogs at risk for pathologic fracture.

Assessment of radial torsion using computed tomography in dogs with and without antebrachial limb deformity.

OBJECTIVE: To evaluate the reliability of radial torsion assessment in dogs using computed tomography (CT). STUDY DESIGN: Cadaveric and retrospective observational clinical study. ANIMALS: Thoracic limbs (n = 40) from bilateral normal cadaveric canine specimens (10 pairs) and unilateral antebrachial angular limb deformity (ALD) dogs (10 uniapical and 10 biapical deformities). METHODS: Limbs were evaluated using CT. Frontal, sagittal, and axial plane (torsion) values were obtained using published guidelines and compared between groups and limbs. Radial torsion reliability was assessed among 3 observers using intraclass correlation coefficients (ICC). RESULTS: The mean (±SD) radial torsion of normal dogs was 3.6° ± 6.4° and contained a significant right to left limb variation of 2.6°. Mean radial torsion in uniapical ALD limbs (3.6° ± 18.7°) was not significantly different from biapical ALD limbs (8.9° ± 17.9°). There was a wide range of torsion values in normal and ALD limbs. The interobserver reliability was excellent (ICC > 0.8) for normal dogs, good (0.73) for uniapical, and excellent (0.89) for biapical ALD limbs. The intraobserver reliability was excellent (>0.8) for all groups. CONCLUSION: There was a small side-to-side variation of radial torsion in normal dogs. With directed training, torsion assessment using CT is reliable in dogs with and without antebrachial bone deformity.

Autologous Bone Marrow-Derived Mesenchymal Stem Cells Modulate Molecular Markers of Inflammation in Dogs with Cruciate Ligament Rupture.

Mid-substance rupture of the canine cranial cruciate ligament rupture (CR) and associated stifle osteoarthritis (OA) is an important veterinary health problem. CR causes stifle joint instability and contralateral CR often develops. The dog is an important model for human anterior cruciate ligament (ACL) rupture, where rupture of graft repair or the contralateral ACL is also common. This suggests that both genetic and environmental factors may increase ligament rupture risk. We investigated use of bone marrow-derived mesenchymal stem cells (BM-MSCs) to reduce systemic and stifle joint inflammatory responses in dogs with CR. Twelve dogs with unilateral CR and contralateral stable partial CR were enrolled prospectively. BM-MSCs were collected during surgical treatment of the unstable CR stifle and culture-expanded. BM-MSCs were subsequently injected at a dose of 2x106 BM-MSCs/kg intravenously and 5x106 BM-MSCs by intra-articular injection of the partial CR stifle. Blood (entry, 4 and 8 weeks) and stifle synovial fluid (entry and 8 weeks) were obtained after BM-MSC injection. No adverse events after BM-MSC treatment were detected. Circulating CD8+ T lymphocytes were lower after BM-MSC injection. Serum C-reactive protein (CRP) was decreased at 4 weeks and serum CXCL8 was increased at 8 weeks. Synovial CRP in the complete CR stifle was decreased at 8 weeks. Synovial IFNγ was also lower in both stifles after BM-MSC injection. Synovial/serum CRP ratio at diagnosis in the partial CR stifle was significantly correlated with development of a second CR. Systemic and intra-articular injection of autologous BM-MSCs in dogs with partial CR suppresses systemic and stifle joint inflammation, including CRP concentrations. Intra-articular injection of autologous BM-MSCs had profound effects on the correlation and conditional dependencies of cytokines using causal networks. Such treatment effects could ameliorate risk of a second CR by modifying the stifle joint inflammatory response associated with cranial cruciate ligament matrix degeneration or damage.

Successful Treatment of Mandibular Nonunion With Cortical Allograft, Cancellous Autograft, and Locking Titanium Miniplates in a Dog.

Discontinuities of the mandible can occur for a variety of reasons including primary pathology of bone, pathologic fracture secondary to periodontal disease, and segmental resection for the treatment of neoplasia. Surgical intervention is necessary in many cases to establish normal occlusion and normal mandibular function. Rigid stabilization and treatment of these defects can be challenging due to the limited availability of bone for fixation as well as limited soft tissue coverage. This case report describes successful treatment of a nonunion fracture using cortical allograft and locking titanium miniplates. Complete osseointegration and bone healing were achieved, allowing for complete return to normal occlusion and function.

Mechanical Evaluation of Locking, Nonlocking, and Hybrid Plating Constructs Using a Locking Compression Plate in a Canine Synthetic Bone Model.

OBJECTIVE: To evaluate the mechanical properties of locking screw placement in hybrid plating in comparison to all-locked and all nonlocked constructs. STUDY DESIGN: Completely randomized design. Forty-eight synthetic bone cylinders (4th generation composite Sawbones(®)) across 6 construct types (n = 8 each). METHODS: An 8-hole 3.5 mm LCP was placed across a 2 mm cylinder gap to mimic an unstable fracture model. The plates were secured with all locking screws, all nonlocking screws, or a combination of locking screws and nonlocking screws in the hybrid constructs. Constructs were cyclically tested nondestructively in 4-point bending, axial compression, and torsion, and then tested to failure in torsion. The stiffness and strength of each construct were calculated and compared across construct types. RESULTS: Constructs with a locking screw located adjacent to the fracture gap were stiffer in bending and stronger in torsion to failure than constructs without an adjacent locking screw. Hybrid and nonlocking screw constructs more frequently failed by catastrophic breakage of the bone cylinder, compared to all locking screw constructs that failed by plastic deformation of the plate. CONCLUSIONS: Mechanical testing of synthetic bone model constructs shows that hybrid constructs are at least as stiff and strong as entirely nonlocked constructs, and with some screw configurations, are not statistically different from entirely locked constructs.

Focal defect resembling a subchondral bone cyst of the ulnar trochlear notch in a dog.

A 13 mo old spayed female golden retriever/standard poodle mixed-breed dog was presented for intermittent right forelimb lameness. Physical examination revealed marked effusion and decreased flexion in the right elbow joint, radiography showed mild osteophytosis of the right elbow joint, and computed tomography showed a focal defect in the subchondral bone in the trochlear notch of the ulna resembling a subchondral bone cyst. Arthroscopy of the affected elbow revealed a focal defect in the articular cartilage on the trochlear notch with vascular ingrowth covering a defect in the subchondral bone plate. The synovium surrounding the defect was inflamed. To the authors' knowledge, this is the first published report of a subchondral bone cyst in the ulna of a dog.

Arthroscopic assessment of stifle synovitis in dogs with cranial cruciate ligament rupture.

Cranial cruciate ligament rupture (CR) is a degenerative condition in dogs that typically has a non-contact mechanism. Subsequent contralateral rupture often develops in dogs with unilateral CR. Synovitis severity is an important factor that promotes ligament degradation. Consequently, we wished to evaluate the utility of arthroscopy for assessment of stifle synovitis in dogs with CR. Herein, we report results of a prospective study of 27 dogs with unilateral CR and bilateral radiographic osteoarthritis. Arthroscopic images and synovial biopsies from the lateral and medial joint pouches were obtained bilaterally and graded for synovial hypertrophy, vascularity, and synovitis. Synovial tartrate-resistant acid phosphatase-positive (TRAP+) macrophages, CD3(+) T lymphocytes, Factor VIII+ blood vessels, and synovial intima thickness were quantified histologically and related to arthroscopic observations. Risk of subsequent contralateral CR was examined using survival analysis. We found that arthroscopic scores were increased in the index stifle, compared with the contralateral stifle (p<0.05). Numbers of CD3+ T lymphocytes (SR = 0.50, p<0.05) and TRAP+ cells in joint pouches (SR = 0.59, p<0.01) were correlated between joint pairs. Arthroscopic grading of vascularity and synovitis was correlated with number density of Factor VIII+ vessels (SR>0.34, p<0.05). Arthroscopic grading of villus hypertrophy correlated with numbers of CD3(+) T lymphocytes (SR = 0.34, p<0.05). Synovial intima thickness was correlated with arthroscopic hypertrophy, vascularity, and synovitis (SR>0.31, p<0.05). Strong intra-observer and moderate inter-observer agreement for arthroscopic scoring was found. Dog age and arthroscopic vascularity significantly influenced risk of contralateral CR over time. We conclude that arthroscopic grading of synovitis is a precise tool that correlates with histologic synovitis. Arthroscopy is useful for assessment of stifle synovitis in client-owned dogs, and could be used in longitudinal clinical trials to monitor synovial responses to disease-modifying therapy.