Loïc M. Déjardin

Tissue-Engineered Rotator Cuff Tendon Using Porcine Small Intestine Submucosa Histologic and Mechanical Evaluation in Dogs

To determine its efficacy in stimulating the regeneration of a rotator cuff tendon, an implant of 10-ply porcine small intestinal submucosa was used to replace a completely resected infraspinatus tendon in 21 adult mongrel dogs. The contralateral infraspinatus tendon was elevated and then reattached to the greater tubercle with sutures to mimic conventional repair (sham operation). Mechanical evaluations were performed at 0, 3, and 6 months (five specimens at each time period). Histologic comparisons were made at 3 and 6 months (three specimens). At both times, the gross appearance, histologic continuity, and failure mode of the constructs mimicked those of sham-operated and native infraspinatus tendons, thus suggesting host tissue ingrowth and implant remodeling with solid integration of the regenerated tissue to muscular and bony interfaces. Tissue ingrowth occurred without histologic evidence of foreign body or immune-mediated reactions or adhesions to peripheral tissues. Sham operations simulated tendon mobilization and reimplantation procedures routinely performed to treat chronic rotator cuff tendon injuries. Although the ultimate strength of small intestinal submucosa-regenerated tendons was significantly less than that of native infraspinatus tendons (P<0.001), it was similar to that of reimplanted tendons at 3 (P<0.05) and 6 months (P<0.05).

Use of small intestinal submucosal implants for regeneration of large fascial defects: An experimental study in dogs

A single layer of porcine small intestinal submucosa (SIS) was sutured into a 5 x 5 cm window created in the fascia lata of ten adult mongrel dogs in order to determine the efficacy of this material in promoting tissue regeneration of large fascial defects. A similar defect in the contralateral limb was left empty and served as a negative control. Tissue regeneration was examined grossly and histologically at 6 and 12 weeks. By 6 weeks, marked fibroplasia and angiogenesis had occurred throughout the SIS scaffold. The regenerated tissue was well organized and showed good integration with the adjacent fascia while the control specimens were filled with loose areolar connective tissue. At 12 weeks the experimental defects were filled with a regenerated tissue that grossly and histologically resembled normal fascia. There was no evidence of adhesions to the underlying musculature. Conversely, the tissue that filled the control defects remained disorganized and was markedly thinner than the adjacent fascia. The results of this study suggest that SIS is capable of supporting tissue regeneration in large fascial defects. The ability of this material to induce regeneration of a substantial area of tissue grossly and histologically similar to normal fascia and without adhesions to the underlying musculature makes its application in reconstructive surgery appear promising.

Prospective evaluation of minimally invasive plate osteosynthesis in 36 nonarticular tibial fractures in dogs and cats.

Objective: To evaluate the clinical outcome of minimally invasive plate osteosynthesis (MIPO) for nonarticular tibial fractures stabilized using bone plates with or without an intramedullary rod (IMR). Study Design: Prospective study. Animals: Dogs (n=28) and 8 cats. Methods: After closed reduction, fracture fixation was achieved using an epiperiosteal plate inserted percutaneously through epiphyseal small incisions. In some fractures, an IMR was inserted via medial parapatellar arthrotomy. Radiographs were recommended every 3 weeks until clinical union. Postoperative tibial length and alignment were compared with contralateral measurements (P<.05). Time to clinical union and complications were recorded. Results: An IMR was used in 30.5% of the cases. Repaired tibiae were 1% shorter than contralateral tibiae (P .05). Six dogs were lost for follow-up; owners indicated normal function. In 30 cases for which bone healing was documented, mean±SD healing time was 45±20.8 days; however, when considering the 23 cases, which completed preestablished scheduled follow-ups, healing time was 36±11.6 days. Minor complications occurred in 4 cases (11%). One major complication (3%) consisting of a plate fracture was successfully revised using MIPO with a larger plate. Conclusions: Consistent restoration of alignment was accomplished using MIPO techniques. Furthermore, MIPO appeared to yield faster healing times and lower complication rates than those reported with conventional plate osteosynthesis.OBJECTIVE To evaluate the clinical outcome of minimally invasive plate osteosynthesis (MIPO) for nonarticular tibial fractures stabilized using bone plates with or without an intramedullary rod (IMR). STUDY DESIGN Prospective study. ANIMALS Dogs (n=28) and 8 cats. METHODS After closed reduction, fracture fixation was achieved using an epiperiosteal plate inserted percutaneously through epiphyseal small incisions. In some fractures, an IMR was inserted via medial parapatellar arthrotomy. Radiographs were recommended every 3 weeks until clinical union. Postoperative tibial length and alignment were compared with contralateral measurements (P<.05). Time to clinical union and complications were recorded. RESULTS An IMR was used in 30.5% of the cases. Repaired tibiae were 1% shorter than contralateral tibiae (P<.05). Frontal and sagittal alignment were similar between repaired and contralateral tibiae (P>.05). Six dogs were lost for follow-up; owners indicated normal function. In 30 cases for which bone healing was documented, mean±SD healing time was 45±20.8 days; however, when considering the 23 cases, which completed preestablished scheduled follow-ups, healing time was 36±11.6 days. Minor complications occurred in 4 cases (11%). One major complication (3%) consisting of a plate fracture was successfully revised using MIPO with a larger plate. CONCLUSIONS Consistent restoration of alignment was accomplished using MIPO techniques. Furthermore, MIPO appeared to yield faster healing times and lower complication rates than those reported with conventional plate osteosynthesis.

Traumatic Anterior Cruciate Ligament Tear and its Implications on Meniscal Degradation: A Preliminary Novel Lapine Osteoarthritis Model

BACKGROUND Injury patterns of the meniscus following impact trauma resulting in anterior cruciate ligament (ACL) rupture are not well understood. This study explored the spatial and temporal distribution of meniscal tears in a novel in vivo lapine model. METHODS Skeletally mature Flemish Giant rabbits were subjected to either tibiofemoral impaction resulting in ACL rupture or surgical ACL transection. Meniscal damage was assessed acutely and after 12 wk for traumatically torn, and after 12 wk in ACL transected animals. Morphological grading was assessed using previously established criteria, and descriptions of meniscal damage were diagnosed by a Board certified orthopedist. Histological assessment was also made on 12 wk traumatically torn and ACL transected animals using Fast-Green/Safranin-O staining. RESULTS Traumatic ACL rupture resulted in acute tears predominately in the lateral menisci. Animals subjected to both surgical transection and traumatic ACL rupture experienced degradation of the lateral and medial menisci 12 wk after injury. However, traumatic ACL rupture resulted in acute lateral damage and chronic degradation of the menisci, as well as more severe degradation of the menisci 12 wk after injury. CONCLUSIONS This study showed that unconstrained high-intensity impacts on the tibiofemoral joint lead to meniscal damage in conjunction with ACL ruptures. Both acute and chronic changes to the menisci following traumatic impaction were observed. This research has implications for the future use of lapine models for osteoarthritis, as it incorporates traumatic loading as a more realistic mode contributing to the progression of osteoarthritis (OA) compared to surgically transected models.

Cancellous Bone Grafting of Large Osteochondral Defects: An Experimental Study in Dogs

Autogenous cancellous bone was evaluated as a material to repair large osteochondral defects in 20 adult mongrel dogs. In one knee, the bone graft was used to fill an osteochondral cylindrical defect (10 mm diameter x 10 mm deep) created in the femoral trochlea. A similar lesion was created in the contralateral knee but was left untreated for spontaneous healing. Four animals were killed at each of five periods (2, 4, 8, 12, and 24 weeks), and the healing response of the defects was evaluated by gross anatomic inspection, plain film radiography, high-resolution radiography, and histology. The results of this study suggest that the use of a cancellous bone graft accelerates the repair of large osteochondral defects and produces more uniform filling of the defect than the ungrafted control. The reparative surface of the grafted lesions also differed from that of controls, having uniform coverage with histochemical-positive staining fibrocartilage at 8 weeks, a finding not observed in any control defect through the length of this study, 24 weeks.

The effect of varied electrical current densities on lumbar spinal fusions in dogs.

BACKGROUND CONTEXT The use of electrical stimulation has been shown to increase the rate of successful spinal fusions. It is possible that increasing the current density of these stimulators may increase the speed and success rate of these fusions. PURPOSE This study evaluated the effects of varied current densities on the speed and success rate of spinal fusion in dogs. STUDY DESIGN/SETTING Three different current densities (0.83 microA/cm, 4 microA/cm and 10 microA/cm) were used to stimulate spinal fusions in a canine model over a 12-week period. OUTCOME MEASURES Radiographic and histologic assessments were used to determine the degree of facet fusions at each time period. METHODS Fifteen dogs underwent spinal facet fusion bilaterally at the level of L1-2 and L4-5. Each fusion site was electrically stimulated using one of three current densities. At 6, 9 and 12 weeks, the specimens were evaluated using high-resolution radiography and routine histology. The fusion masses were graded and then statistically evaluated. RESULTS The results demonstrate a dose response of fusion mass scores to increasing current density. The highest current density (10 microA/cm) demonstrated a statistically higher fusion scores than the lowest currently density (0.83 microA/cm) at 6 weeks and statistically greater than both the middle (4 microA/cm) and lowest (0.83 microA/cm) current densities at 9 weeks. No differences were noted at 12 weeks, because all groups showed complete fusion. CONCLUSIONS This controlled study suggests that speed of fusion may be further improved by increasing the current density of the electrical stimulation.

Evaluation of a collagenase generated osteoarthritis biomarker in naturally occurring canine cruciate disease.

OBJECTIVE To determine the clinical value of a novel osteoarthritis (OA) biomarker in detecting canine cruciate disease. STUDY DESIGN Cross sectional clinical study. ANIMALS Dogs (n=22) with cranial cruciate ligament (CCL) rupture and 12 control dogs. METHODS Concentrations of collagenase-generated cleavage epitope of type II collagen (Col2-3/4C(long mono), or C2C) in serum, urine, and joint fluid were compared between a group of dogs with CCL rupture and a control group. Correlation of C2C concentrations to the clinical stage of stifle OA was also evaluated. RESULTS There were no significant differences in C2C concentrations in serum, urine, and joint fluid between groups (P>.05). Subjective scores of lameness, joint effusion, osteophytosis were significantly more severe in the CCL rupture group compared with the control group (P<.05). There was no significant correlation of C2C concentrations with clinical stage of stifle OA (P>.05). CONCLUSION This OA biomarker did not detect pathology associated with CCL rupture. Our results suggest that collagenase-specific degradation of type II collagen in articular cartilage may not be involved in the early stage of naturally occurring canine cruciate disease, and that pathology associated with naturally occurring CCL rupture is different from that of experimental OA model. CLINICAL RELEVANCE C2C is not clinically useful in detecting CCL rupture in dogs.

Tibial Plateau Symmetry and the Effect of Osteophytosis on Tibial Plateau Angle Measurements

A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2 degrees between right and left tibial plateau angles, which was considered symmetrical.

The Effect of an Exogenous Fibrin Clot on the Regeneration of the Triangular Fibrocartilage Complex: An In Vivo Experimental Study in Dogs

The effect of an exogenous fibrin clot on the regeneration of the triangular fibrocartilage complex (TFCC) was examined in a dog model. In 12 mature dogs, bilateral TFCC resection was performed. The resulting defect was packed with an exogenous fibrin clot (experimental) while the contralateral side was left empty (control). Tissue regeneration was evaluated grossly and histologically at 6, 12, and 26 weeks. At each time period, the regenerated tissue in the fibrin clot-filled defect appeared more mature and more congruent with the adjacent cartilaginous surfaces than did the control (empty) defect. At 26 weeks, the clot regenerated tissue had the histological appearance of a normal TFCC with a homogeneous fibrocartilaginous matrix, regularly oriented collagen fibers, and normal integration with the adjacent support structures of the joint. The results of this study indicate that an exogenous fibrin clot could be used to promote a fibrocartilaginous repair tissue for a resected TFCC. Such therapy could be used in the arthroscopic treatment of TFCC injury and resection in an effort to improve postoperative outcome.

Does Osgood-Schlatter Disease exist in the dog? Review of human and canine literature and proposed classification system for tibial tuberosity avulsions in the immature dog.

Osgood-Schlatter disease (OSD) is a condition affecting human adolescents in which there is partial separation of bone fragments from the tibial tuberosity at the site of insertion of the patellar ligament to the tibial tuberosity. Tensile trauma seems to be the most likely aetiology. Clinical signs in people consist of swelling and pain at the proximal part of the tibial tuberosity and around the distal end of patellar ligament. Radiographs frequently show small ossicles at the patellar ligament insertion. Conservative treatment is usually curative. The term OSD has also been used for the canine patient. However, radiographs of these patients typically show an enlarged radiolucent line at the apophyseal plate of the tibial tuberosity. This finding is consistent with a mild avulsion fracture of the canine tibial tuberosity. Based on the radiographic differences between the two species, it seems more appropriate to use the term OSD only for people. The purpose of this paper is to review the literature on OSD in people and the reports of injuries to the proximal tibial tuberosity in dogs. In addition, a new classification system for tibial tuberosity avulsion injuries in the immature dog is proposed, with an algorithm for management of this injury.