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1.
OBJECTIVES: To report an ovine model that can be used to evaluate the efficacy of bone substitutes for repair of segmental diaphyseal bone defects. STUDY DESIGN: Experimental study. ANIMALS: Eleven 2-year-old Pré-Alpes Sheep. METHODS: Mid-diaphyseal metatarsal bone defects (25 mm long) were stabilized by a dynamic compression plate over a polymethylmethacrylate (PMMA) cement spacer, and by external coaptation. The PMMA spacer was removed at 6 weeks by incising the encapsulating membrane. The defect remained unfilled (Group 1; n=5) or was filled with morselized autologous corticocancellous graft (Group 2; n=6), the membrane sutured closed, and external coaptation applied for 6 months, when healing was evaluated. RESULTS: Radiographic, computed tomographic, and histologic examinations at 6 months after the 2nd surgery revealed non-union in ungrafted defects whereas grafted defects showed bone healing. The induced membrane had blood vessels, CBFA1+ cells, and very few macrophages entrapped in a collagenous tissue positive for type I collagen. CONCLUSION: This ovine metatarsal defect model resulted in a critical-size defect (non-union) that healed when grafted. The PMMA-induced membrane constrained the graft, was well vascularized, and may have osteogenic properties. CLINICAL RELEVANCE: This model may be useful to evaluate new strategies in bone tissue engineering because the PMMA-induced membrane may help confine bone morphogenetic proteins, skeletal stem cells, or other agents to the defect cavity where they could be useful to enhance bone formation.  相似文献   

2.
OBJECTIVE: To evaluate a femoral window technique for retrieval of cemented total hip prostheses. STUDY DESIGN: Retrospective clinical study. ANIMALS: Twelve dogs with infection of a cemented modular total hip prosthesis. METHODS: Implant removal was performed by an extended craniolateral approach to the hip and proximal femur without trochanteric osteotomy. The femoral cement mantle was fragmented and removed with simple orthopedic instrumentation by a lateral femoral window that was repaired using cerclage wires. Surgical technique, intraoperative and postoperative complications, bacterial culture results, histopathologic findings, and completeness of cement removal were recorded. Follow-up radiographs were taken 5 to 9 weeks postoperatively. Long-term follow-up information was obtained by client questionnaire. Functional outcome was assessed by scoring ability to stand, sit, walk, run, play, climb stairs, and get into a car. RESULTS: Prosthesis retrieval was performed 2 to 41 months after implantation (median, 14 months). Complete removal of femoral cement was achieved in 10 dogs. A nondisplaced femoral fissure, extending proximally from the window, was an intraoperative complication in 2 dogs. Staphylococcus spp was most commonly isolated (6 dogs) from interfacial membrane samples. Systemic antibiotic therapy, dependent on susceptibility testing, was administered for 3 to 10 weeks postoperatively. There was radiographic evidence of osteotomy healing at 5- to 9-week reassessment. Recurrence of osteomyelitis was not observed. Long-term functional outcome was considered mildly abnormal. CONCLUSIONS: The lateral window was an effective technique for retrieval of retained femoral cement. CLINICAL RELEVANCE: Removal of an infected prosthesis using this technique generally resulted in a clinical outcome comparable to that with ab initio femoral head and neck excision.  相似文献   

3.
Clinical orthopaedic use of calcium phosphate cement has been limited due to its slow resorption rate, but a new macroporous alpha-tricalcium phosphate (alpha-TCP) bone cement has been designed to accelerate resorption and to increase bone ingrowth. To assess its clinical potential, the in vivo behaviour of alpha-TCP was evaluated in a critical-size defect drilled in the femoral condyles of 36 adult female New Zealand rabbits. Macroporous or standard cement was injected immediately after preparation of the defect. The foaming agent was albumen, which gave up to 75% porosity. The rabbits were divided into three groups and the lesions examined histopathologically at 1, 4 and 12 weeks. No inflammatory reaction was detected at any time period following implantation with either macroporous or standard cement. At 12 weeks, the area of the implanted macroporous cement was approximately 35% of the initial lesion size. Bone growth and revascularisation was observed inside the central pores of the macroporous cement, not only at the margins, as was found with standard calcium phosphate cement. The results indicated that both cements were osteoconductive, biocompatible and biodegradable but their different physicochemical and biological properties had a marked influence on their post-implant behaviour.  相似文献   

4.
The present study was undertaken to evaluate porous hydroxyapatite (HAp), the powder of which was prepared by a novel aqueous solution combustion technique, as a bone substitute in healing bone defects in vivo, as assessed by radiologic and histopathologic methods, oxytetracycline labeling, and angiogenic features in Bengal goat. Bone defects were created in the diaphysis of the radius and either not filled (group I) or filled with a HAp strut (group II). The radiologic study in group II showed the presence of unabsorbed implants which acted as a scaffold for new bone growth across the defect, and the quality of healing of the bone defect was almost indistinguishable from the control group, in which the defect was more or less similar, although the newly formed bony tissue was more organized when HAp was used. Histologic methods showed complete normal ossification with development of Haversian canals and well-defined osteoblasts at the periphery in group II, whereas the control group had moderate fibro-collagenization and an adequate amount of marrow material, fat cells, and blood vessels. An oxytetracycline labeling study showed moderate activity of new bone formation with crossing-over of new bone trabeculae along with the presence of resorption cavities in group II, whereas in the control group, the process of new bone formation was active from both ends and the defect site appeared as a homogenous non-fluoroscent area. Angiograms of the animals in the control group showed uniform angiogenesis in the defect site with establishment of trans-transplant angiogenesis, whereas in group II there was complete trans-transplant shunting of blood vessel communication. Porous HAp ceramic prepared by an aqueous combustion technique promoted bone formation over the defect, confirming their biologic osteoconductive property.  相似文献   

5.
OBJECTIVE: To determine the practicality and clinical outcome of miniature total hip replacement (THR) in dogs. STUDY DESIGN: Retrospective study. Sample Population- Seventeen client-owned dogs that had miniature THR. METHODS: Patient data surveyed included signalment, body weight, diagnosis, implant size, surgical technique, and intraoperative and postoperative complications. Radiographic evaluation included angle of lateral opening of the acetabular component, implant positioning, cement mantle quality, and femoral displacement measurement and ratio. Client questionnaire and orthopedic examination were used to obtain long-term follow-up information. RESULTS: Miniature THR was performed to address hip dysplasia and secondary osteoarthritis. In 1 dog, a staged bilateral procedure was performed. Mean body weight was 19 kg (range, 12 to 25 kg). Penetration or fissure of the femoral cortex was the most common intraoperative complication and occurred in 3 dogs. In 3 dogs, there was excessive coxofemoral laxity after reduction of the prosthesis. This instability was addressed specifically in 2 dogs by capsulorrhaphy or capsular prosthesis. Postoperative convalescent complications (craniodorsal luxation, 2 dogs; acetabular cup displacement, 1 dog) were related to surgical errors. Aseptic loosening of the femoral implant was diagnosed in 1 dog at 18 months. Mean follow-up time was 17 months (range, 4 to 42 months). Fifteen of 18 (83%) miniature THRs had good or excellent outcomes. CONCLUSIONS: Miniature THR should be considered a satisfactory alternative to femoral head and neck ostectomy in medium-size dogs affected by hip dysplasia and secondary osteoarthritis. The population of medium-size dogs that might derive more benefit from THR than FHO has yet to be defined. CLINICAL RELEVANCE: Miniature THR is a viable treatment option in medium-size dogs with hip dysplasia.  相似文献   

6.
OBJECTIVE: To evaluate the effect of arthroscopic subchondral bone microfracture on healing of large chondral defects in horses. STUDY DESIGN: Short- (4 months) and long-term (12 months) in vivo experimental chondral defect model. ANIMALS: 10 horses, aged 2 to 5 years. METHODS: Each horse had a 1 cm2 full-thickness chondral defect created in both radial carpal bones and both medial femoral condyles. One carpus and one femoral condyle of each horse had the subchondral bone plate under the defect perforated using an orthopedic awl. All horses were exercised, five horses were evaluated after 4 months and five horses after 12 months. Gross, histologic, and histomorphometric examination of defect sites and repair tissues was performed, as was collagen typing of the repair tissue. RESULTS: On gross observation a greater volume of repair tissue filled treated defects (74%) compared with control defects (45%). Histomorphometry confirmed more repair tissue filling treated defects, but no difference in the relative amounts of different tissue types was observed. There was an increased percentage of type II collagen in treated defects compared with control defects and evidence of earlier bone remodeling as documented by changes in porosity. CONCLUSIONS: In full-thickness chondral defects in exercised horses, treatment with subchondral bone microfracture increased the tissue volume in the defects and the percentage of type II collagen in the tissue filling the defects when compared to nontreated defects. CLINICAL RELEVANCE: No negative effects of the microfracture technique were observed and some of the beneficial effects are the basis for recommending its use in patients cases with exposed subchondral bone.  相似文献   

7.
OBJECTIVES: To evaluate the effects of different cementing techniques on radiographic cement mantle grade and short-term aseptic loosening of the femoral component in canine total hip replacement (THR). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Radiographs of 284 dogs that had THR. METHODS: Immediate postoperative radiographs of 284 dogs that had cemented THR were reviewed by 4 surgeons and 1 radiologist and assigned a cement mantle grade using a 4-grade classification system. Dog age and weight at surgery, cementing technique (1st, 2nd, 3rd generation), complications (type and timing), and follow-up time were retrieved and analyzed. RESULTS: Mean cement mantle score for 2nd generation technique was significantly higher than 3rd generation technique and both were significantly higher than 1st generation technique (P<.001). Aseptic loosening was the 2nd most common complication observed with an incidence of 2.1%. Mean time from surgery to last follow-up examination was 122 days. No statistically significant difference in incidence of aseptic loosening was identified among different cement mantle grades or cementing techniques. CONCLUSIONS: Advanced cementing techniques resulted in better cement mantles based on grading of immediate postoperative radiographs, however grading did not predict short-term aseptic loosening. Cementing technique seemingly did not affect the incidence of short-term aseptic loosening of the femoral component for dogs in this study. CLINICAL RELEVANCE: Our study suggests that advances in cementing technique may result in improvements in the radiographic grade of cement mantles. With respect to aseptic loosening of the femoral component, our data only suggest that short-term (3 months-3 years) loosening cannot be predicted by immediate postoperative radiographic evaluation of cement mantle.  相似文献   

8.
OBJECTIVE: To report the clinical, radiographic, and pathologic features of extraosseous cement granuloma (ECG), a low occurrence, long-term complication of total hip replacement (THR). STUDY DESIGN: Retrospective clinical study. Sample Population-Six client-owned dogs. METHODS: Medical records for 6 dogs that had a cemented modular THR and developed ECG were reviewed for the clinical, radiologic, and histopathologic findings of ECG. Morphologic and elemental analyses of retrieved particles were conducted in 2 dogs using scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). RESULTS: Three golden retrievers and 3 Labrador retrievers had progressive lameness in the operated limb 4 to 7 years after THR and developed ECG. Other clinical features included an acute deterioration to non-weight bearing associated with pathologic fracture of the proximal femur in 2 dogs, and obstipation in 1 dog. In 5 dogs, there was a large caseous mass surrounding the proximal femur. Obstipation in 1 dog was caused by a similar mass adjacent to bone cement used for fixation of the acetabular cup. Radiographic changes included a multilobular soft tissue mass, containing irregular mineral densities, in the gluteal mass surrounding the proximal femur, THR interface deterioration, osteolysis, new bone formation, and implant subsidence were consistent with chronic aseptic loosening. The histopathologic diagnosis was sterile granuloma associated with a massive heterogeneous particulate burden, which was assumed to have resulted from severe wear of all prosthesis components. CONCLUSIONS: ECG is a manifestation of severe aseptic loosening of cemented total hip replacement, with the generation of wear debris probably responsible for granuloma formation. CLINICAL RELEVANCE: Because revision can offer a good prognosis in early aseptic femoral loosening, yearly radiographic monitoring of the recipients is recommended.  相似文献   

9.
For future clinical use as synthetic bone replacement, an injectable brushite-(chronOS-Inject) and hydroxylapatite-(Biobon) cement were compared in a drill hole model in 10 sheep over time at 2, 4, 6, 8, 16 and 24 weeks. Results were compared regarding their practical use, biocompatibiliy, resorption mechanism and subsequent new bone formation. The cements were filled into drill holes (psi 8 x 13mm) of the proximal and distal humerus, and femur and the samples evaluated macroscopically, radiologically and microscopically including histomorphometrical quantification of percentages of new bone, fibrous tissue and remnants of cements. The cement area decreased continuously from 2 to 24 weeks with chronOS-Inject, as well as the area of granules. Inversely, the subsequent new bone formation increased from 2-24 weeks accordingly. With Biobon the cement area decreased slower between 2 and 24 weeks, and the new bone formation was less. Both cements were well integrated into the bone in long bones. chronOS-Inject demonstrated good biocompatibility and was almost completely replaced through bone within 24 weeks. Biobon was resorbed considerably slower and initially a slight inflammatory reaction including bone resorption was observed within the adjacent host bone.  相似文献   

10.
The radiographic signs associated with implanted canine total hip prostheses include: (1) a 1 mm-or-less wide static lucent zone at the acetabular and femoral bone-cement interfaces, and (2) periosteal bone proliferation surrounding the stem of the femoral prosthesis. The radiographic signs associated with total hip replacement complications are dislocation of the femoral component, bone changes suggestive of infection involving the acetabular and femoral components, and loosening of the acetabular component. Arthrography is beneficial in determining the presence of a loose prosthesis with or without infection.  相似文献   

11.
OBJECTIVE: To determine the effects of femoral prosthesis stem length and head size on cement strains in a canine hip replacement system. STUDY DESIGN: An in vitro experimental model. SAMPLE POPULATION: (1) Three standard and 3 1-cm shortened femoral implants with +3 femoral heads. (2) Two standard implants with +0, +3, and +6 femoral heads. METHODS: Femoral stems were embedded in polymethylmethacrylate cement. A uniaxial proximodistal-oriented strain gauge was applied to the cement on the medial and lateral aspects of the construct 1.5 cm, 6.0 cm and 7.0 cm distal to the collar. Each construct with a +3 femoral head was mounted in a materials testing system. An axial compressive load (0-200 N) was applied to the femoral head and cement strains were recorded. Additionally, 2 standard length constructs were also tested with +0 and +6 femoral heads. The effects of stem length and neck length on cement strains were assessed with analysis of variance. RESULTS: Strains increased at all locations with increasing loads for all constructs. Shorter implants had higher strains by 152% and 171%, lateral (P =.003) and medial (P =.0025) to the stem tip. No significant strain differences were noted, at any strain gauge location, between different neck lengths (P values ranged from.20 to.67). CONCLUSIONS: Although a shorter implant stem has a potential to improve implant fit, it led to significantly higher cement strains that may increase the risk for aseptic loosening. Changes in femoral neck length did not significantly affect cement strains under the conditions tested. CLINICAL RELEVANCE: Shortening of the femoral stem currently cannot be recommended in canine total hip replacement. The existing use of variable neck lengths likely does not increase the risk of failure of the femoral stem.  相似文献   

12.
The medical records of 171 dogs with traumatic hip luxations were examined. German shepherds, mixed breeds, and poodles were significantly overrepresented. The mean age of the patients at the time of diagnosis was 4.4 years (range 5 months to 14 years). Vehicular trauma caused 83% of the 133 luxations where the etiology was known; 53% had at least one other diagnosed traumatic injury. Long-term results were obtained from owner questionnaires (25 dogs) or clinical and radiographic examinations (11 hip joints). The short-term recurrence rate after closed reduction (47.3%) was higher than that after surgical reduction using any of the three surgical techniques most frequently used here (9.5, 12.5, and 14.3%), even when the operation was performed after failure of a closed reduction (11.8%). Excluding dogs that had a femoral head ostectomy, 68% (17 of 25) of the dogs had a normal gait, 16% had only a mild lameness, and 16% had more severe lameness when evaluated on an average of 31 months after repair. Of 11 hip joints radiographed on an average of 25 months following repair, five had no radio-graphic abnormalities related to the luxation and six showed one or more of the following: periosteal new bone formation, femoral head subluxation, partial resorption of the femoral head, periarticular osteophytes, and subchondral bone erosion. Closed reduction should be the initial treatment of choice in uncomplicated luxations even though the rate of reluxation is high, because it avoids the need for surgery in approximately one half of affected dogs and does not increase the recurrence rate following subsequent surgical reduction.  相似文献   

13.
OBJECTIVE: To compare fit and geometry of reconstruction of femoral components of 4 canine cemented total hip replacement implants and determine which implants are most compatible with current principles of cemented arthroplasty. SAMPLE POPULATION: Paired femurs from 16 adult mixed-breed dogs. PROCEDURE: Femurs were prepared for femoral stem implantation of either the Bardet, BioMedtrix, Mathys, or Richards II implant. Mediolateral and craniocaudal radiographs were obtained with femoral components in situ. Cross-sectional analysis of implant fit was performed on transected cemented specimens. Computer-aided analyses of digitized images were performed. RESULTS: The Bardet and Richards II implants reconstructed the original femoral head position significantly better than the other 2 implants. None of the implants allowed neutralization of the implant axis in the sagittal plane or were routinely centralized in the femoral canal.The Bardet implant had the smallest minimum distal tip offset in the sagittal plane. Greatest tip to cortex distance was provided by the Richards II implant in the transverse plane and the Mathys implant in the sagittal plane. The thinnest cement mantle regions for all implants were in the central longitudinal third of the femoral stem. CONCLUSIONS AND CLINICAL RELEVANCE: The Bardet and BioMedtrix implants had stem design characteristics that were most compatible with principles of cemented stem fixation. None of the implants completely satisfied the theoretically optimal conditions of centralization and neutralization of the femoral stem. Innovative design modifications, therefore, may be needed if these conditions are important to the long-term success of canine total hip replacement.  相似文献   

14.
Changes in physiological parameters that are induced by acute exercise on a treadmill in healthy military dogs have not been thoroughly investigated, especially with regard to age. This study investigated the effects of acute exercise on a treadmill on cardiovascular function, biochemical parameters and gastric antral motility in military dogs. Thermography was used to assess variations in superficial hindlimb muscle temperature. Nine healthy dogs were distributed into three groups according to their age (Group I: 25 ± 7 months; Group II: 51 ± 12 months; Group III: 95 ± 10 months) and sequentially subjected to running exercise on a treadmill for 12 min (3.2 km/h at 0° incline for 4 min, 6.4 km/h at 0° incline for 4 min and 6.4 km/h at 10° incline for 4 min). Heart rate, systolic and diastolic arterial pressure (DAP), gastric motility, haematocrit and biochemical analyses were performed at rest and after each session of treadmill exercise. Infrared thermographic images of muscles in the pelvic member were taken. Exercise decreased DAP in Group I, increased systolic arterial pressure in Groups II and III and increased mean arterial pressure in Group III (all p < 0.05). After the exercise protocol, plasma creatine kinase and aspartate aminotransferase levels increased only in Group I (p < 0.05). Exercise increased heart rate and decreased the gastric motility of a solid meal at 180 min in all groups (all p < 0.05). Exercise also elevated temperature in the femoral biceps muscles in Group I compared with the older dogs. The results indicate that acute exercise decreased gastric motility in dogs, regardless of age, and caused more pronounced cardiovascular changes in older dogs than in younger dogs. Acute exercise also altered biochemical parameters and superficial hindlimb muscle temperature in younger military dogs.  相似文献   

15.
For the in vivo evaluation of hip joint prostheses that are developed for man, the suitability of the pony as an animal model has been studied. Human and custom made prostheses were implanted into 1 femur in each of 7 ponies to replace the femoral head. The surgical approach was through a caudolateral incision. The prosthesis was fixed in the femur with bone cement. Because of errors in the implantation technique and resulting lack of sufficient fixation 2 ponies as well as 1 control animal with an excision arthroplasty were unwilling or unable to stand. Rigid fixation of the implant was achieved in 3 ponies. They were returned to pasture after 8 days. A full return to a normal gait did not occur within an observation period of up to 3 months. All 3 ponies developed a dorsolateral coxofemoral luxation and pseudarthrosis within the first 10 days. A mismatch between the equine anatomy and human prosthesis geometry was thought to be the cause. We, therefore, believe that the pony does not provide a suitable model for the testing of human femoral joint implants. The results, however, indicate that coxofemoral surgery can be performed in the adult pony. For clinical reconstruction of joint function, a custom made total artificial hip joint might provide better results.  相似文献   

16.
The purpose of this study was to investigate the effect of the nonsteroidal anti-inflammatory drug carprofen on bone turnover and to monitor the progress of chronic osteoarthritic dogs by measuring different bone markers and radiographic evalutation of the corresponding joints. For this purpose 20 dogs of different ages and weight were devided into 2 groups. Ten dogs were assigned to Group R, treated with carprofen, and ten dogs to Group C, which had no treatment. Radiographs of the affected joints were reviewed initially and six months later at the end of the experiment. Blood was taken 8 times from each dog. Four bone markers (Osteocalcin (OC), bone-specific alkaline phosphatase (bAP), carboxyterminal telopeptide of type I collagen (ICTP), serum CrossLaps (CTX) as well as 1,25-(OH)2-Vitamin D and parathyroid hormone (PTH) were monitored for 6 months. No significant group effects on bone markers were notied. In Group R a decrease in ICTP concentrations during the first three months and a significant decrease in CTX concentrations in the first two months of the study were observed. The bone formation marker bAP revealed a significant decrease throughout the experiment. Three dogs of Group C and one dog of Group R showed osteoarthritic progression in the radiographs. The significant decrease of CTX indicates that carprofentreatment could have a retarding effect on the progression of osteoarthritis. Radiological findings suggest that carprofen may delay osteophyte formation. The monitoring of focal metabolic processes as in bone of a osteoarthrotic joint is difficult, since the bone mass is very active and metabolic processes may have an influence on the monitoring.  相似文献   

17.
Sixteen tenorrhaphies were performed at mid-metatarsal region in eight buffalo calves. A 2-cm long gap was created in the superficial digital flexor (SDF) tendon in all animals. The gap was immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II, and in group III the defect was repaired with autografts (control group). The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Gross observation revealed filling of host tendon-graft junction with fibrous connective tissue. Increased vascularity was seen in group I when compared with group II and III. Graft was resorbed in animals of group I and III, whereas partial absorption of graft was seen in group II. Histological observations on day 30 revealed restoration of cellularity in acellular graft and fragmentation and resorption of glutaraldehyde-preserved graft. Graft was replaced by newly formed fibrous connective tissue. Tissue reaction around polygalactin suture consisted of plasma cells, lymphocytes and macrophages. On day 90, most of the acellular graft was replaced by newly formed fibrous connective tissue. In group II the majority of graft portion remained at the site and was in a state of resorption. In the control group it was difficult to distinguish between the host tendon and the graft. Scanning electron microscopical observation showed densely packed neoformed tissue at host tendon-graft junction. Hydrolysis and invasion of connective tissue between polygalactin suture filaments, resorption of graft with cavity formation and dissolution of ground substance were observed.  相似文献   

18.
OBJECTIVE: To investigate the relationship between stage of estrous cycle and bone cell activity in Thoroughbreds. SAMPLE POPULATION: Blood samples collected from forty-seven 2-year-old Thoroughbred mares in training for racing. PROCEDURES: Blood samples were collected monthly (in April through September) from the mares. Stage of estrus was determined by assessing serum progesterone concentration. Bone cell activity was determined by measuring concentrations of 2 markers of bone formation (osteocalcin and the carboxy-terminal propeptide of type I collagen [PICP]) and a marker of bone resorption (the cross-linked carboxy-terminal telopeptide of type I collagen [ICTP]) in sera. RESULTS: When the relationship between stage of the estrous cycle and markers of bone cell activity was examined, serum concentrations of both osteocalcin and ICTP were significantly higher in mares that were in the luteal phase, compared with mares that were at other stages of the estrous cycle. Stage of estrus did not affect serum PICP concentration. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that bone cell activity in Thoroughbred mares fluctuates during the estrous cycle; serum concentrations of markers of bone formation and bone resorption are increased during the luteal phase. Further studies are required to determine whether these changes are of clinical importance and increase the risk of injury for mares in training during the breeding season. As in humans, stage of estrus must be considered as a source of uncontrollable variability in serum bone marker concentrations in horses.  相似文献   

19.
OBJECTIVES: To define the release of nitric oxide (NO), prostaglandin E2 (PGE2), and the neutral metalloproteinases (NMPs) in horses with subchondral cystic lesions (SCL) and to study bone resorption triggered by conditioned media of fibrous tissue of SCL in vitro. STUDY DESIGN: Equine explant cultures of fibrous tissue of SCL, and synovial membrane and articular cartilage of normal horses and horses affected with moderate and severe osteoarthritis were performed. NO, PGE2, and NMP concentrations of media samples were measured, and osteoclast formation and activation was studied in vitro. ANIMALS: Experiment 1: 32 horses with SCL (n = 8), normal joints (7), and joints with moderate (7) and severe (10) osteoarthritis (OA). Experiment 2: 22 horses with SCL (n = 3), normal joints (7), and chip fractures (12). Experiment 3: Conditioned media of fibrous tissue from 3 horses with SCL of the medial femoral condyle (n = 1), distal metacarpal bone (1), and tarsal bone (1). METHODS: Determinations of local mediator concentrations were made with the Griess assay for NO and an enzyme immunoassay kit for PGE2 concentrations in biological fluids. Enzyme activities were assessed with radiolabeled substrates indicating collagenolytic, gelatinolytic, and caseinolytic activities. The resorption pit assay was used to assess osteoclast recruitment and activity. RESULTS: Fibrous tissue of SCL produced NO, PGE2, and NMPs. Of all the variables measured, PGE2 concentrations were the highest in cystic tissue of SCL compared with synovial membrane and articular cartilage from normal joints and joints with chip fractures, indicating that this mediator may play an important role in pathological bone resorption associated with SCL. These findings were supported by the observation that conditioned media of SCL tissue were capable of recruiting osteoclasts and increasing their activity. CONCLUSION: Fibrous tissue of SCL released NO, PGE2, and NMPs into the culture media. It is suspected that intralesional fibrous tissue may play an active role in the pathological process of bone resorption occurring in SCL in horses and may be partly responsible for the maintenance, slow healing rate, and expansion of these lesions. CLINICAL RELEVANCE: Understanding the pathogenesis of SCL will help to establish successful therapy in horses affected with SCL.  相似文献   

20.
Objective— To compare the quality of second-intention healing and that of compacting sternally harvested cancellous bone into subchondral bone defects of the medial femoral condyle in horses.
Study Design— A controlled experiment using a surgical technique that minimizes soft tissue trauma, customized for consistency among horses.
Animals or Sample Population— Ten horses, aged 2 to 5 years, free of hindlimb lameness and with radiographically normal stifles.
Methods— After a 12.7-mm-diameter × 19-mm-deep defect was created into randomly selected medial femoral condyles, bone and cartilage healing was evaluated over a 6-month period in control horses (  n = 5  ) and horses receiving a compacted cancellous bone graft (  n = 5  ). Healing was evaluated using lameness assessment, radiographic and microradiographic interpretation, arthroscopic appearance, percent bone fill, proteoglycan content, and histology.
Results— Six months after surgery, there was no significant difference between grafted and ungrafted defects with respect to lameness, radiographic score, or percent bone fill. Histologically, grafted defects were characterized by the presence of dead graft and secondary cyst formation in four defects. Ungrafted defects filled with fibrous tissue and no cyst formation were identified.
Conclusions— Grafted defects do not heal better than ungrafted defects, and lameness was not affected by surgical technique.
Clinical Significance— Cartilage healing is similar in grafted and ungrafted defects in the equine medial femoral condyle at 6 months, suggesting that surgical debridement alone of cystic structures remains the treatment of choice.  相似文献   

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