Objective—To determine the in vitro effects of selected growth factors on fibrochondrogenesis by synovial membrane cells from nonosteoarthritic (normal) and osteoarthritic joints of dogs.
Animals—5 dogs with secondary osteoarthritis of shoulder or stifle joints and 6 dogs with normal joints.
Procedures—Synovial membrane cells were harvested from normal and osteoarthritic joints and cultured in monolayer with or without (control) basic fibroblast growth factor, transforming growth factor-β1, and insulin-like growth factor-1. In the cultured cells, fibrochondrogenesis was measured by use of a real-time reverse transcriptase PCR assay to determine relative expressions of collagen I, collagen II, and aggrecan genes and of 3 genes involved in embryonic chondrogenesis: Sry-type homeobox protein-9 (SOX-9), frizzled-motif associated with bone development (Frzb), and regulator of G-protein signaling-10 (RGS-10). Tissue collagen content was measured via a hydroxyproline assay, and sulfated glycosaminoglycan content was measured via a 1,9-dimethylmethylene blue assay. Cellularity was determined via a double-stranded DNA assay. Immunohistochemical analysis for collagens I and II was also performed.
Results—In vitro collagen synthesis was enhanced by growth factor stimulation. Although osteoarthritic-joint synoviocytes could undergo a fibrocartilage-like phenotypic shift, their production of collagenous extracellular matrix was less than that of normal-joint synoviocytes. Gene expressions of SOX-9 and RGS-10 were highest in the osteoarthritic-joint cells; Frzb expression was highest in growth factor treated cells.
Conclusions and Clinical Relevance—Autogenous synovium may be a viable cell source for meniscal tissue engineering. Gene expressions of SOX-9 and RGS-10 may be potential future targets for in vitro enhancement of chondrogenesis.
Objective—To compare biomaterials used in orthopedics with respect to in vitro cell viability and cell retention and to in vivo tissue healing and regeneration.
Animals—65 adult female Sprague-Dawley rats and synovium, tendon, meniscus, and bone marrow specimens obtained from 4 adult canine cadavers.
Procedures—Synovium, tendon, meniscus, and bone marrow specimens were used to obtain synovial fibroblasts, tendon fibroblasts, meniscal fibrochondrocytes, and bone marrow–derived connective tissue progenitor cells for culture on 5 biomaterials as follows: cross-linked porcine small intestine (CLPSI), non–cross-linked human dermis, cross-linked porcine dermis, non–cross-linked porcine small intestine (NCLPSI), and non–cross-linked fetal bovine dermis. After 1 week of culture, samples were evaluated for cell viability, cell density, and extracellular matrix production. Biomaterials were evaluated in a 1-cm2 abdominal wall defect in rats. Each biomaterial was subjectively evaluated for handling, suturing, defect fit, and ease of creating the implant at the time of surgery, then grossly and histologically 6 and 12 weeks after surgery.
Results—All biomaterials allowed for retention of viable cells in culture; however, CLPSI and NCLPSI were consistently superior in terms of cell viability and cell retention. Cell infiltration for NCLPSI was superior to other biomaterials. The NCLPSI appeared to be replaced with regenerative tissue most rapidly in vivo and scored highest in all subjective evaluations of ease of use.
Conclusions and Clinical Relevance—These data suggested that NCLPSI and CLPSI have favorable properties for further investigation of clinical application in orthopedic tissue engineering.
Case Description—A 1-year-old 7.4-kg (16.3-lb) castrated male mixed-breed dog was evaluated because of intermittent lameness and an antebrachial angular limb deformity.
Clinical Findings—The left forelimb had gross antebrachial external rotation (approx 90°) and marked procurvatum. Radiography revealed a severe partially compensated biapical antebrachial angular limb deformity. Measurements of medial proximal radial angle (MPRA) and lateral distal radial angle (LDRA) were obtained from orthogonal radiographs of the proximal and distal segments of the radius, respectively. Elbow joint-to-carpus translation was quantified. Deformities were localized and quantified by the center of rotation of angulation (CORA) method. Computed tomographic 3-dimensional image reconstructions of the antebrachium and carpus were completed to create 3 life-size stereolithographic models.
Treatment and Outcome—2 closing wedge radial osteotomies were performed at the level of the CORAs and stabilized with bone plates and screws.
Results—Frontal and sagittal plane alignments were corrected to 8° and 15°, respectively (reference limits, 0° to 8° and 8° to 35°, respectively). The MPRA was corrected from 55° to 68°, and LDRA was corrected from 32° to 76° (values considered normal are approx 85° and 87°, respectively). Elbow joint-to-carpus translation was improved by 42.5%. After 8 weeks, radiography revealed bone union. Owners considered the outcome acceptable, on the basis of limb appearance and lack of lameness at 1 year after surgery.
Conclusions and Clinical Relevance—A segmental radiographic planning technique combined with the CORA method, computed tomography, and stereolithography may be useful in the characterization of and planning corrective surgery for forelimb deformities in dogs.
Objective—To determine outcome of open toggle rod stabilization in dogs with luxation of the hip joint.
Design—Retrospective case series.
Procedures—Information on signalment, surgical procedure, and postoperative care was obtained from the medical records. A questionnaire was sent to all owners to solicit follow-up information.
Results—The distribution for time between luxation and surgery was bimodal, with 24 (39%) dogs examined ≤ 2 days after injury and 23 (37%) examined > 7 days after injury. Postoperative complications developed in 16 of the 62 (26%) dogs, with complications developing within 1 week after surgery in 10 of the 16. The most common complication was reluxation, which occurred in 7 dogs. Dogs in which surgery time was < 2 hours were significantly less likely to have a reluxation (2/40 [5%]) than were dogs in which surgery time was ≥ 2 hours (5/22 [23%]). When asked to rate current limb function (0 = no lameness and 5 = non–weightbearing lame) a minimum of 6 months after surgery, 23 of 27 (85%) owners indicated a score of 0 or 1.
Conclusions and Clinical Relevance—Results of the present study suggest that toggle rod stabilization is an effective treatment for hip joint luxation in dogs. However, complications, particularly reluxation, were common.