OBJECTIVE:The aim of this study was to define the extent of the biceps tendon, subscapularis tendon, and cranial border of the medial glenohumeral ligament within the field of view during standard lateral shoulder arthroscopy in the dog. We also examine the effect of joint flexion on the field of view of the biceps tendon.STUDY DESIGN:This was a cadaveric study using 21 shoulders of large breed dogs. Each shoulder was explored with a 30-degree arthroscope using standard lateral ports. For each supporting structure, the margins within the arthroscopic field of view were marked with ink. In 11 shoulders, the distal margin of the biceps tendon was identified and marked first with the limb at a standing angle and then in flexion. The margins of the cranial border of the medial glenohumeral ligament were marked at the standing angle. In 10 additional shoulders, the margins of the subscapularis tendon were evaluated. Each joint was fully dissected and the portion of each stabilizing structure within the field of view was quantified.RESULTS:Fifty-eight percent of the cranial border of the medial glenohumeral ligament was within the arthroscopic view. At a standing angle, 48% of the intra-articular length of the biceps tendon was within the arthroscopic view, compared to 63% with the limb flexed. Twenty percent of the subscapularis tendon was within the arthroscopic view.CONCLUSION:A significant portion of the biceps tendon and medial stabilizing structures of the canine shoulder are outside the field of view of arthroscopy through a standard lateral approach. The limitations of the arthroscopic field of view should be appreciated when evaluating the shoulder.

Dogs are commonly affected with cruciate ligament rupture (CR) and associated osteoarthritis (OA), and frequently develop a second contralateral CR. Platelet rich plasma (PRP) is a component of whole blood that contains numerous growth factors, which in combination with a collagen scaffold may act to promote bioenhanced primary repair of ligament. This study tested the hypothesis that treatment of partial stable CR stifles with an intra-articular collagen scaffold and PRP would decrease the disease progression, synovitis and risk of complete CR over a 12-month study period. 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. All dogs were treated with tibial plateau leveling osteotomy (TPLO) on the unstable stifle and a single intra-articular application of PRP-collagen in the stable partial CR stifle. Dogs were evaluated at the time of diagnosis, and at 10-weeks and 12-months after treatment. We evaluated correlation between both development of complete CR and time to complete CR with diagnostic tests including bilateral stifle radiographs, 3.0 Tesla magnetic resonance (MR) imaging, and bilateral stifle arthroscopy. Additionally, histologic evaluation of synovial biopsies, C-reactive protein (CRP) concentrations in serum and synovial fluid, and synovial total nucleated cell count, were determined. Results indicated that a single application of PRP-collagen in partial CR stifles of client owned dogs is not an effective disease-modifying therapy for the prevention of progression to complete CR. Radiographic effusion, arthroscopic evaluation of cranial cruciate ligament (CrCL) damage, and MR assessment of ligament fiber tearing in partial CR stifles correlated with progression to complete CR over the 12-month follow-up period. We determined that the best predictive model for development of complete CR in PRP-collagen treated partial CR stifles included variables from multiple diagnostic modalities.

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.

Canine cranial cruciate ligament rupture is often bilateral and asymmetrical, ranging from partial to complete rupture. The purpose of our diagnostic accuracy study was to assess the accuracy of 3 Tesla magnetic resonance imaging (MRI) detection of fiber loss and use of a visual analog scale in the diagnosis of complete versus partial cranial cruciate ligament rupture in 28 clinical dogs with unilateral complete rupture and contralateral partial rupture. Three Tesla MRI was performed on 56 stifles using sagittal sequences (T2-weighted fast spin echo with fat saturation, proton density fast spin echo, and T2-weighted 3D fast spin echo CUBE). Two MRI observers assessed the cranial cruciate ligament for fiber loss and completed a visual analog scale. The MRI data were compared to arthroscopy and clinical status. Accuracy classifying partial or complete rupture was assessed using receiver operating characteristic analysis. Compared to arthroscopy, for complete cranial cruciate ligament rupture, sensitivity, specificity, and accuracy of MRI detection of fiber loss were 0.78, 0.50-0.60, and 0.68-0.71, respectively, and, for partial tears, specificity was 1.00. An MRI visual analog scale score ≥79 was indicative of complete cranial cruciate ligament rupture (sensitivity 0.72-0.94 and specificity 0.71-0.84). Using a visual analog scale cut-point ≥79, observers achieved good accuracy discriminating clinical status of partial or complete cranial cruciate ligament rupture (area under the curve 0.87-0.93). MRI evaluation for fiber loss and use of a visual analog scale are specific in stifles with clinically stable partial cranial cruciate ligament rupture. In stifles with clinically unstable complete cranial cruciate ligament rupture, both MRI tests are sensitive though not specific compared to arthroscopy. As a diagnostic imaging method, MRI may help guide treatment in patients with cranial cruciate ligament damage, particularly for stable partial rupture.

Tibial plateau leveling osteotomy (TPLO) was first described in 1993 by Slocum to address stifle instability due to cruciate ligament rupture (CR). Preoperative determination of the patient's tibial plateau angle (TPA) allows calculation of the magnitude of rotation necessary to achieve a desired post- operative TPA. Appropriate case selection is important to the success of TPLO. A wide range of orthopaedic implant manufacturers produce commercially available TPLO implants in a growing variety of sizes. The use of locking bone screws causes significantly less translational movement of the proximal tibial segment towards the bone plate compared to the use of conventional bone screws in an identical plate. A retrospective evaluation of change in TPA during bone healing and radiographic osteotomy stability showed no difference between non-locking and locking plates. Despite the potential complications, outcome after TPLO has been reported as favorable in both large- and small-breed dogs.

Orthopedic examination and diagnostic tools -- Fractures: classification, diagnosis, and treatment -- Bone grafting -- Delayed union and nonunion -- Treatment of acute and chronic bone infections -- Arthrology -- Principles of joint surgery -- Arthroscopy in joint surgery -- Fractures of the scapula -- The shoulder joint -- Fractures of the humerus -- The elbow joint -- Fractures of the radius and ulna -- Fractures and other orthopedic conditions of the carpus, metacarpus, and phalanges -- Fractures of the pelvis -- The hip joint -- Fractures of the femur and patella -- The stifle joint -- Fractures of the tibia and fibula -- Fractures and other orthopedic injuries of the tarsus, metatarsus, and phalanges -- Fractures and luxations of the mandible and maxilla -- Fractures in growing animals -- Correction of abnormal bone growth and healing -- Disease conditions in small animals.

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.

Summary Case description: A 10-year-old female Belgian Teruven dog was presented to our clinic for total hip revision following a diagnosis of implant (cup) failure with metallosis and abdominal pseudotumour formation. The patient had a cementless metal-on-polyethylene total hip replacement performed nine years prior to presentation. Clinical findings: The clinical findings, including pseudotumour formation locally and at sites distant from the implant and pain associated with the joint replacement, were similar to those described in human patients with this condition. Histopathological, surgical, and radiographic findings additionally supported the diagnosis of metallosis and pseudotumour formation. Treatment and outcome: Distant site pseudo -tumours were surgically removed and the total hip replacement was explanted due to poor bone quality. The patient recovered uneventfully and has since resumed normal activity. Conclusion: In veterinary patients with metal-on-polyethylene total hip implants, cup failure leading to metallosis and pseudo-tumour formation should be considered as a potential cause of ipsilateral hindlimb lameness, intra-pelvic abdominal tumours, or a combination of both. These clinical findings may occur years after total hip replacement surgery.