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Biomedical subjects

C E Kawcak

Publications and source records attributed to C E Kawcak.

At least 19 recordsLinked to original sources
PubMed2004

Assessment of subchondral bone mineral density in equine metacarpophalangeal and stifle joints.

Functional relationships between articular cartilage and underlying subchondral bone have been shown to be associated with the progression of osteoarthritis (OA). However, quantifiable factors substantiating this relationship do not exist. Therefore, the study objective involved quantifying subchondral bone mineral density (BMD) of the equine metacarpophalangeal (MCP) and stifle joints as a step in determining if regional subchondral BMD may be associated with OA changes. BMD was bilaterally quantified using dual energy xray absorptiometry (DEXA) for four subchondral regions: palmer and dorsal aspect of the medial 3rd metacarpal (MC3P, MC3D), medial femoral condyle (MFC), and the medial trochlear ridge (MTR). BMD (g/cm2) was measured using a 5.2 x 5.2 mm region of interest in the subchondral bone area. To account for the differences in thickness, BMD (g/cm2) was divided by sample thickness providing volumetric BMD (g/cm3). No significant effect of side on BMD values was found (p > 0.72). However, there were significant differences in BMD found between all regions (p < 0.05). The volumetric BMD of the MC3P region was significantly greater than the MC3D and the MC3D was greater than the MFC, while the MFC was greater than the MTR (MC3P > MC3D > MFC > MTR). The MCP regions had a higher volumetric BMD than the stifle regions possibly due to higher weight distribution, smaller articular surface area, and joint geometry. The adaptive bone structural variations between the regions studied were shown to be significant. Mechanical properties of the overlying cartilage are currently being analyzed to correlate with these results and provide a possible diagnostic method to investigate OA progression.

Absorptiometry, Photon↗
PubMed2001

The role of subchondral bone in joint disease: a review.

Subchondral bone plays a role in the pathogenesis of osteochondral damage and osteoarthritis in horses and humans. Osteochondral fragmentation and fracture, subchondral bone necrosis and osteoarthritis are common diseases in athletic horses, and subchondral bone is now thought to play an integral role in the pathogenesis of these diseases. There have been numerous research efforts focused on articular cartilage damage and its pathogenesis, yet comparatively little effort focused on subchondral bone pathology or the coordinated disease states of the osteochondral tissues. The purpose of this report is to review the current understanding of osteochondral disease in all species and its application to equine research and practice. It can be concluded from this review that our current understanding of osteochondral disease is based on clinical and pathological sources; and that the lack of information about joint tissue adaptation and disease has hampered objective studies of osteochondral tissues.

Animals↗
PubMed2000

Clinical effects of exercise on subchondral bone of carpal and metacarpophalangeal joints in horses.

OBJECTIVE: To determine effects of treadmill exercise on subchondral bone of carpal and metacarpophalangeal joints of 2-year-old horses. ANIMALS: 12 healthy 2-year-old horses. PROCEDURE: Horses were randomly assigned to the control (n = 6) or exercised (6) groups. Horses in the exercised group ran on a high-speed treadmill 5 d/wk for 6 months. Horses in the control group were hand walked for the same amount of time. Results of clinical, radiographic, nuclear scintigraphic, and computed tomographic examinations, and serum and synovial concentrations of biochemical markers of bone metabolism were compared between groups. RESULTS: Exercised horses were significantly lamer at the end of the study than control horses. Radionuclide uptake in the metacarpal condyles, but not in the carpal joints, was greater in exercised horses, compared with control horses. Exercised horses also had a higher subchondral bone density in the metacarpal condyles than control horses, but such differences were not detected in the carpal bones. CONCLUSIONS AND CLINICAL RELEVANCE: None of the diagnostic techniques evaluated was sufficiently sensitive to detect all osteochondral damage. Computed tomography and computed tomographic osteoabsorptiometry were superior to conventional radiography for detecting small osteochondral fragments. Nuclear scintigraphy was a sensitive indicator of subchondral bone change but lacked specificity for describing lesions and discerning normal bone remodeling from damage. Newer techniques such as computed tomography may help clinicians better diagnose early and subtle joint lesions in horses prior to development of gross joint damage.

Animals↗
PubMed2000

The effect of initiation of exercise training in young horses on vitamin K status.

Twelve Quarter Horses, 18 to 24 mo of age and having an average body weight of 460+/-12 kg, were randomly assigned to one of two exercise treatments (control and exercise) to study the effect of initiation of exercise training in young horses on vitamin K status. The control treatment consisted of hand-walking the horses 7 min/d and 5 d/wk for 180 d. Exercise consisted of the following treadmill exercise regimen: 2 min at 4.5 to 5.4 m/s, 3 min at 13.4 to 14.3 m/s, and 2 min at 4.5 to 5.4 m/s on 5 d/wk for 180 d. Both groups were allowed free access to brome grass hay (273 mg of phylloquinone/100 g) individually. Additionally, the exercise group was fed .45 kg of a grain-mix concentrate (40 mg of phylloquinone/100 g) on the days they were exercised. Jugular venous blood samples were collected at d 0, 30, 60, 90, 120, 150, and 180. Blood samples were analyzed for total serum osteocalcin and vitamin K status via the hydroxyapatite binding capacity of serum osteocalcin calculated as follows: Hydroxyapatite binding capacity of serum osteocalcin = [(total serum osteocalcin - serum osteocalcin following extraction of serum with hydroxyapatite)/total serum osteocalcin] x 100. All horses were killed with an overdose of sodium pentobarbital on d 180. Computed tomographic osteoabsorptiometry was used to measure relative bone density distribution on the surface of the distal radial carpal bone, proximal third carpal bone, and the distal third metacarpal condyle. Relative bone density distribution was measured in Hounsfield units and categorized as low-, medium-, and high-density bone corresponding to 800 to 1,199, 1,200 to 1,299, and 1,300 to 3,000 Hounsfield units, respectively. Carpal and metacarpophalangeal joints were assigned a score of 0 (normal) to 3 (severe) that reflected the presence and severity of joint lesions. Hydroxyapatite binding capacity of serum osteocalcin and serum osteocalcin were unchanged over the 180-d period in both groups. Exercised horses had a higher percentage of high density bone (P < .01) and a lower percentage of low density bone (P < .01) on the surface of the third metacarpal condyle and a higher cumulative gross lesion score (P < .01) in the metacarpophalangeal joint than controls. There were no differences between treatments in relative bone density distribution in the carpal bones, or cumulative gross lesion score of the carpal joints. No significant correlation was present between the serum measures, osteocalcin and hydroxyapatite binding capacity of serum osteocalcin, and the bone measures, relative bone density distribution and joint gross lesion score.

Animals↗
PubMed1999

Calcified cartilage morphometry and its relation to subchondral bone remodeling in equine arthrosis.

The calcified layer of articular cartilage is known to be affected by age and mechanical factors that may play a role in the development of arthrosis. Because these factors are also related to subchondral remodeling and sclerosis, a morphometric study was carried out in fluorochrome-labeled animals to determine whether the level of subchondral remodeling affected the thickness of the calcified cartilage layer and its irregularity and vascularity at the interface with subchondral bone. These parameters were also studied at a site of increased mechanical stress. The area and thickness of the calcified cartilage layer was determined in basic fuchsin-stained ground sections (120 microm). The irregularity of the chondro-osseous interface was expressed as the ratio of its length to that of the relatively straight tidemark (Int/Tid) and the number of abutting vessels with and without fluochrome labels were counted (N.Ves/Tid,%L.Ves/Tid). These were compared with single-labeled surface (sLS/BS, %) in subchondral bone, which was used as an index of remodeling. In a group of 12 horses, in which one carpus had an osteochondral fragment surgically created 10 weeks earlier, there was activation of subchondral remodeling in the third carpal bone opposite the fragment. An increase in %L.Ves/Tid (p < 0.01) at the interface was correlated with the increase in %sLS/BS in subchondral bone (r=0.431, p=0.035). The number of abutting vessels and the interface irregularity were not significantly changed on the fragmented side. In the metacarpal condyles from the fetlock joints of the same horses there were no differences associated with the surgically created fragment in the carpus and no correlation of %L.Ves/Tid with subchondral %sLS/BS. At a site where mechanical overload and traumatic osteochondrosis is known to occur on the palmar surface, the calcified cartilage was thinner, and the interface irregularity tended to be greater. These findings indicate that activated subchondral remodeling extends to involve the calcified layer, but the thickness and irregularity of the calcified cartilage are not consistently related to current subchondral remodeling. At sites of mechanical overload the calcified cartilage was thinner and the interface tended to be more irregular, suggesting previous increased remodeling.

Animals↗
PubMed1998

Subchondral bone failure in an equine model of overload arthrosis.

Gross examination of metacarpo-/metatarsophalangeal (fetlock) joints from racehorses revealed defects on the condylar surface that ranged from cartilage fibrillation and erosion to focal cartilage indentations and cavitation in subchondral bone characteristic of traumatic osteochondrosis. Because these lesions represented a spectrum of mechanically induced arthrosis in which microdamage is thought to play a role, a histologic study of sagittal sections was made to study the morphogenesis. Subchondral bone failure developed beneath a flattened section of the condyle where the margin of the sesamoid bone produces compression as well as shear on impact of the foot with the ground. Milder lesions had thickening of subchondral bone and underlying trabeculae. With advancing sclerosis an increased amount of osteocyte necrosis was present. Occasional vascular channels with plugs of matrix debris and cells were present just beneath the cartilage. There was increased prominence of subchondral vessels, and osteoclastic remodeling was seen in and around the sclerotic zone. Apparent fragmentation lines in the subchondral bone suggested increased matrix fragility. Irregular trabecular microfractures developed at a depth of a few millimeters. Increased vascularity with hemorrhage, fibrin, and fibroplasia could be seen in enlarged marrow spaces at this more advanced stage. The overlying articular cartilage was variably indented but remained largely viable with degeneration and erosion limited to the superficial layers. Focally, breaks in the calcified layer appeared to lead to collapse and cartilage infolding. In metacarpal condyles from experimental horses run on a treadmill, there were milder changes at the site. The subchondral bone was increased in volume and there was increased diffuse staining with basic fuchsin, but no increase in the number of microcracks was seen. The findings in the racehorses indicate that the equine fetlock condyle is a consistent site of overload arthrosis in which microfracture and failure in subchondral bone may occur. Controlled exercise in treadmill horses may provide a model in which to study the pathogenesis.

Animals↗
PubMed1998

The assessment of chondrocyte proteoglycan metabolism using molecular sieve column chromatography as compared to three commonly utilized techniques.

OBJECTIVE: Various methods have been used to quantify [35S] sulfate incorporation into proteoglycans and separate this from unincorporated [35S] sulfate. The methods currently used have not been compared for accuracy or precision, ease of completion and relative economics. This experiment evaluated and compared cetylpyridinium chloride (CPC) precipitation, potassium acetate (KAc) precipitation, rapid filtration, modified dye-binding (AB) technique to molecular weight exclusion chromatography (PD-10) as techniques to quantitate chondrocyte proteoglycan metabolism. METHODS: Each of the first three techniques was compared to the PD-10 technique as a 'gold standard' based on this technique's accuracy, precision and repeatability in molecular weight exclusion utilizing sieve chromatography. Articular cartilage was harvested, cultured and labeled with [35S] sulfate in a routine manner. Seventeen samples were processed and each was analyzed by the four different methodologies. Linear regression analysis was used to predict the linear relationship of PD-10 chromatography to the other methods (CPC, KAc, and AB) in the amount of proteoglycan synthesis in a pulse chase experiment. RESULTS: The KAc and AB methods had a significant linear relationship to the PD-10 method but the CPC did not. The AB technique was much easier than the KAc method to complete although the relative economics were similar per sample, when capital equipment costs were not considered. CONCLUSIONS: Either the KAc or AB methods compared favorably to the PD-10 method, although the AB procedure was much easier, and was more precise and more accurate. The CPC method did not compare favorably to the PD-10 method in precision or accuracy although it was easier and cost effective.

Alcian Blue↗
PubMed1998

Effects of osteochondral fragmentation and intra-articular triamcinolone acetonide treatment on subchondral bone in the equine carpus.

To determine the effects of osteochondral fragmentation and intra-articular corticosteroid treatment on dynamics of bone remodelling and fragility, 12 horses each had a unilateral, 8 mm osteochondral fragment created in the distal aspect of one radiocarpal bone. Six of the horses were treated in the fragmented joint, and the other 6 were treated in the nonfragmented joint with 12 mg of triamcinolone acetonide (TA) 14 and 28 days after surgery. All horses were exercised on a high-speed treadmill starting 15 days, and ending 72 days after surgery. Horses treated with TA in the fragmented joints were significantly less lame than those treated in the nonfragmented joints. Third carpal bones from joints with fragments showed significantly more vascularity, single labelled surface, total labelled surface and mineralising surface in subchondral and subjacent trabecular bone. Trends were also seen towards higher vascular canal volume and osteochondral junction remodelling sites in third carpal bones from fragmented joints. No significant differences were seen in microdamage density or size between fragmented and nonfragmented joints. No significant influence of TA treatment was seen on any parameter measured. The results from this study show that osteochondral fragmentation induces significant changes in remodelling of opposing bones, and that the administration of corticosteroids into joints with fragmentation does not significantly alter bone remodelling or fragility.

Animals↗
PubMed1998

Effects of 6alpha-methylprednisolone acetate on an equine osteochondral fragment exercise model.

OBJECTIVE: To determine effects of intra-articularly administered 6alpha-methylprednisolone acetate (MPA) in exercised horses with carpal osteochondral fragmentation. ANIMALS: 18 horses: 3 groups of 6 each. PROCEDURE: An osteochondral (chip) fragment was created in 1 randomly chosen middle carpal joint of each horse. Polyionic fluid (PF) was injected into both middle carpal joints of horses in the control group. In horses of the MPA-control group, MPA was injected into the middle carpal joint without an osteochondral fragment; a similar volume of PF was injected into the contralateral middle carpal joint. In the MPA-treated group of horses, 100 mg of MPA was injected into the middle carpal joint containing the osteochondral fragment; a similar volume of PF was injected into the contralateral joint. Injections were administered on postsurgical days 14 and 28, and horses were exercised on a high-speed treadmill for 8 weeks, starting on postsurgical day 15. RESULTS: Clinical improvement in degree of lameness was not associated with MPA administration. Joints that contained an osteochondral fragment and were treated with MPA had lower prostaglandin E2 concentration in synovial fluid, and lower scores for intimal hyperplasia and vascularity in synovial membrane, compared with PF-treated joints. However, articular cartilage erosion and morphologic lesions suggested possible deleterious effect of intra-articular MPA administration. CONCLUSIONS: Some beneficial effects of MPA administration on synovial fluid and synovial membrane were identified; however, the deleterious findings contrast with those associated with triamcinolone acetonide used in a similar model, but agree with other results of MPA administration in normal and abnormal joints.

Animals↗
PubMed1997

Effects of triamcinolone acetonide on an in vivo equine osteochondral fragment exercise model.

The objective of this study was to determine the effects of intra-articularly administered triamcinolone acetonide (TA) in exercised equine athletes with carpal osteochondral fragmentation. Eighteen horses were randomly assigned to each of 3 groups. An osteochondral chip fragment was created in one randomly chosen intercarpal joint of each horse. Both intercarpal joints in the placebo control group (CNT) horses were injected with intra-articular administration (IA) of polyionic fluid. Both joints in the TA control group (TA CNT) horses were treated with 12 mg of TA in the intercarpal joint without an osteochondral fragment, and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. The TA treated group (TA TX) horses were treated with 12 mg of TA in the joint that contained the osteochondral fragment and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. All horses were treated IA on days 13 and 27 after surgery and exercised on a high speed treadmill for 6 weeks starting on Day 14. Horses in the TA TX group were significantly less lame than horses in the CNT and TA CNT groups. Horses in either TA CNT or TA TX groups had lower total protein, and higher hyaluronan, and glycosaminoglycan concentrations in synovial fluid than did those in the CNT group. Synovial membrane collected from subjects in TA CNT and TA TX groups had significantly less inflammatory cell infiltration, subintimal hyperplasia and subintimal fibrosis compared to the CNT group. Articular cartilage histomorphological parameters were significantly better from the TA CNT and TA TX groups compared to the CNT group. In conclusions, results from this study support favourable effects of TA on degree of clinically detectable lameness, and on synovial fluid, synovial membrane, and articular cartilage morphological parameters, both with direct intra-articular administration and remote site administration as compared to placebo treatment. The clinical use of IA administered TA in horses may be therapeutically beneficial in selected cases of osteochondral fragmentation and osteoarthritis.

Animals↗
PubMed1997

Effects of intravenous administration of sodium hyaluronate on carpal joints in exercising horses after arthroscopic surgery and osteochondral fragmentation.

OBJECTIVE: To evaluate the effects of arthroscopic surgery, osteochondral fragmentation, and treatment with IV administered hyaluronate on histologic, histochemical, and biochemical measurements within the carpal joints of horses. ANIMALS: 12 clinically normal horses, 2 to 7 years of age. PROCEDURE: Horses had an osteochondral fragment created at the distal aspect of the radiocarpal bone of 1 randomly chosen middle carpal joint to simulate osteochondral fragmentation. Horses were treated with 40 mg of hyaluronate or saline solution (placebo) intravenously once a week for 3 consecutive weeks (days 13, 20, and 27 after surgery). Treadmill exercise proceeded 5 days per week beginning 15 days, and ending 72 days, after surgery. Clinical evaluations were performed at the beginning and end of the study. Synovial fluid samples were obtained aseptically from both middle carpal joints on days 0, 13, 20, 27, 34, and 72 after surgery, and total protein, inflammatory cell, hyaluronate, glycosaminoglycan, and prostaglandin E2 concentrations were measured in each sample. All horses were euthanatized on day 72. Synovial membrane and articular cartilage were obtained for histologic evaluation. Articular cartilage samples were also obtained aseptically for determining glycosaminoglycan content and chondrocyte synthetic rate for glycosaminoglycans. RESULTS: Horses treated with hyaluronate intravenously had lower lameness scores (were less lame), significantly better synovial membrane histologic scores, and significantly lower concentrations of total protein and prostaglandin E2 within synovial fluid 72 days after surgery, compared with placebo-treated horses. Treatment with intravenously administered hyaluronate had no significant effects on glycosaminoglycan content, synthetic rate or morphologic scoring in articular cartilage, or other synovial fluid measurements. CONCLUSION: Intravenously administered hyaluronate appears to alleviate signs of lameness by interacting with synoviocytes, and by decreasing production and release of inflammatory mediators.

Animals↗
PubMed1996

Surgical materials and wound closure techniques.

Recent innovations in surgical materials have helped to enhance wound healing and protect surgical wounds from infection. Materials such as polyglyconate have been evaluated in equine tissues and found efficacious. Other materials, such as poliglecaprone 25, appear to have qualities useful to equine surgery but are untested in equine tissues. Care must be taken to fully evaluate a new surgical material because its usefulness in equine tissues may not match that in human or laboratory animal tissues. Furthermore, use of disposable materials in surgery, although considered ideal for maintenance of sterility, may come under more scrutiny in the future as environmental issues gain prominence. We tend to reserve disposable materials for prolonged procedures and for procedures that carry high risk of failure if infection develops.

Animals↗
PubMed1996

Maintenance of equine articular cartilage explants in serum-free and serum-supplemented media, compared with that in a commercial supplemented medium.

OBJECTIVE: To evaluate the effects of a commercially defined, serum-free medium additive on equine articular cartilage explants, compared with effects of serum-free and serum-supplemented media. ANIMALS: Articular cartilage from a 3-year-old, mixed breed horse euthanatized for reasons other than musculoskeletal disease or sepsis. PROCEDURE: Media were changed every 48 hours, and the glycosaminoglycan (GAG) content was determined in media collected at each time point. Glycosaminoglycan synthesis by explant chondrocytes, and residual GAG content of articular cartilage (as a measure of explant GAG loss) were determined at the end of the study (day 8). RESULTS: Articular cartilage explants in serum-free medium and the commercial supplemented medium had significantly lower GAG synthesis and GAG content than did those incubated in serum-supplemented medium. There were no significant differences in GAG synthesis and content between serum-free and commercial supplemented medium groups. When comparing medium GAG content for all treatment groups, the GAG content in serum-free medium on day 8 was significantly greater than that in commercial supplemented medium, but significant differences were not evident in percentage of release of GAG (as an indicator of GAG degradation) among all 3 treatment groups. CONCLUSIONS: Commercial supplemented medium had effects on articular cartilage matrix GAG loss into medium equal to those of serum-supplemented medium (eg, both lost articular cartilage explant GAG to a similar degree). However, residual articular cartilage GAG content was higher in serum-supplemented medium, as was GAG synthesis. Commercial supplemented medium appears to either lack the proper ingredients to maintain steady-state GAG synthesis, or lacks proper concentrations of these ingredients.

Analysis of Variance↗
PubMed1995

Diagnosis and management of incomplete fracture of the distal palmar aspect of the third metacarpal bone in five horses.

Incomplete fracture of the distal palmar aspect of the third metacarpal bone was diagnosed in 5 horses. Mild to moderate lameness and positive response to flexion of the metacarpophalangeal joint were evident in all horses. Fractures were not detectable in 4 horses when the routine 30 degrees proximodorsal-palmarodistal radiographic view was used. Visualization of the fractures in these 4 horses required imaging of the palmar condylar surface by use of a dorsopalmar view of the flexed joint or a 125 degrees dorsoproximal-dorsodistal view. The dorsopalmar view of the flexed joint was used in a fifth horse to evaluate fracture healing when the fracture was no longer evident on routine radiographic views. Scintigraphy was used to locate the fracture sites in 2 horses. Treatment in all horses involved rest with gradual return to exercise, and all horses returned to their previous levels of racing. Scintigraphy and imaging of the palmar condylar surface of the third metacarpal bone allow for a more complete evaluation when other diagnostic images are within normal limits.

Animals↗
PubMed1995

Abnormalities in oxygenation, coagulation, and fibrinolysis in colonic blood of horses with experimentally induced strangulation obstruction.

OBJECTIVE: To measure arterial and venous blood gas, coagulation, and fibrinolysis variables in blood from isolated segments of control and ischemic large colons for the purpose of identifying variables for rapid, indirect assessment of colonic mucosal injury. DESIGN: Variables were determined at specific intervals during the 4-hour study (3 hours of ischemia and 1 hour of reperfusion). ANIMALS: Seven clinically normal horses between 2 and 15 years old. PROCEDURES: Horses underwent laparotomy and occlusion of the lumen and vasculature of the mid-portion of the pelvic flexure of the large colon. During ischemia of 1 randomly-chosen colonic segment, variables were measured to determine colonic mucosal damage and were compared with histologic scores of colonic biopsy specimens. RESULTS: Significant (P < 0.05) differences from control values were observed over time for venous pH, PCO2, PO2, oxygen saturation, oxygen content, arteriovenous oxygen difference, and lactate and glucose concentrations. Mean histologic scores of biopsy specimens obtained from ischemic colons were significantly (P < 0.05) greater (indicating greater damage) than those from control colons, and increased significantly (P < 0.05) with duration of ischemia. CONCLUSIONS: Venous lactate, oxygen saturation, and PO2 values were the most significant predictors of the severity of histologic damage within the ischemic colons (R2 = 0.661). CLINICAL RELEVANCE: Venous blood gas and lactate values in the large colon are good predictors of the amount of intestinal damage incurred during 3 hours of ischemia, and may be clinically useful for the rapid determination of colonic viability.

Animals↗
PubMed1994

Proximodorsal first phalanx osteochondral chip fragmentation in 336 horses.

The results of arthroscopic surgery in the treatment of osteochondral fragmentation of the proximodorsal aspect of the first phalanx and the influence of other fetlock joint lesions on prognosis were evaluated in 336 horses. Horses were classified as: 1) returning to previous use at the same or higher class of performance; 2) returning to previous use (regardless of class of performance); or 3) failing to return to previous use. Ninety-six horses (29%) had fragmentation alone; 140 horses (42%) had fragmentation and additional fetlock lesions, and 100 horses (29%) underwent concurrent carpal arthroscopy. Of the 100 horses that underwent carpal arthroscopy, 63 had proximodorsal first phalanx fragmentation alone and 37 had other fetlock lesions associated with the fragment. There was significant association between lesion type and return to previous use for the Thoroughbred racehorse group. There was also a significant association between lesion type and return to the same or higher class of racing for the Thoroughbred racehorse group. No significant association in return to previous use existed for racehorses vs. non-racehorses, Thoroughbred racehorses vs. Quarter Horse racehorses, single vs. multiple joint involvement, and single vs multiple fragmentation per joint. The Thoroughbred racehorses in this study were sensitive to additional fetlock or carpal lesions, as was exemplified by the significant effect lesion type had on outcome.

Animals↗
PubMedDate not supplied

Comparison of bone healing by demineralized bone matrix and autogenous cancellous bone in horses.

OBJECTIVE: The purpose of this study was to compare bone healing induced by equine demineralized bone matrix (DBM) to autogenous cancellous bone graft (ACB) or no graft (control) in a rib-defect model in horses. STUDY DESIGN: The osteogenic properties of ACB and DBM were evaluated in bilateral 19-mm circular defects created in the outer cortex of the 6th and 8th ribs of each horse. ANIMALS OR SAMPLE POPULATION: Eight mature horses. METHODS: Three rib defects in each horse were randomly treated with each of the 3 treatment groups, and the fourth rib defect received a random treatment. Rib sections, including the defects, were harvested 56 days after implantation and examined for bone mineral density, percent ash and calcium and graded for signs of radiographic and histological healing. RESULTS: All ribs were fractured at the defect site and were classified as nonunion fractures 56 days after implantation. There were no significant differences among groups in bone mineral density and signs of radiographic or histological healing. There was an increased volume of bone in control and ACB-treated sites compared with DBM-treated sites. Rib defects treated with ACB were significantly higher in percent ash and calcium than those treated with DBM. DBM elicited no inflammatory reaction, and remodeling occurred around the periphery and within vascular channels of the decalcified particles. CONCLUSION: DBM particles remodel from the periphery, which may explain the significantly lower percent ash, calcium, and bone when compared with ACB, because 2- to 4-microL pieces of DBM may act as space-occupying masses until completely mineralized. There was no evidence of enhanced healing associated with the use of DBM in this model. CLINICAL RELEVANCE: Particles of 2 to 4 mm DBM should not be used as an aid to fracture repair because particles of this size interfere with normal mineralization. However, our model of nonunion fracture healing may be useful in future studies.

Animals↗