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Biomedical subjects

M B Hurtig

Publications and source records attributed to M B Hurtig.

18 recordsLinked to original sources
PubMed2006

Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint.

REASONS FOR PERFORMING STUDY: To improve osteochondral graft reconstruction of subchondral cystic lesions in the medial and lateral femoral condyles by matching the material properties of donor and recipient sites. OBJECTIVES: To measure biomechanical and biochemical parameters that influence the function and healing of osteochondral grafts used to reconstruct subchondral cystic lesions. HYPOTHESIS: Suitable donor sites are available within the stifle joint for reconstructing the femoral condyles, despite considerable regional property variation. METHODS: Fifty-six osteochondral cores were harvested from 6 distal femurs for initial studies that determined subchondral bone modulus of elasticity and ultimate stress. In a second study, 28 osteochondral cores were harvested from 6 distal femurs to measure cartilage aggregate modulus, thickness and sulphated glycosaminoglycan (sGAG) content. Using micro-CT imaging, subchondral bone mineral density and bone volume fraction were also measured. In both studies 2-dimensional contour plots using a bicubic interpolation method and normalised data were generated to allow visual comparison of joint surface characteristics. Statistical comparisons between donor and recipient site raw data were made using an ANOVA for repeated measures with a post hoc Tukey test. RESULTS: Material properties of cartilage and bone vary considerably over the surface of the stifle joint but the central region of the medial condyle, where subchondral cystic lesions freqdently occur, typically demonstrated bone strength and modulus values of the highest observed. Cartilage thickness and aggregate modulus were highest in the medial femoral condyle and axial aspect of the lateral condyle. CONCLUSIONS: Material properties of the grafts from the trochlear groove and axial aspect of the lateral trochlear ridge were the closest match for those found in the medial condyle, whereas properties of the lateral condyle were most similar to those found in the trochlear groove and axial aspect of the medial trochlear ridge.

Analysis of Variance↗
PubMed2001

An investigation of 2 techniques for optimizing joint surface congruency using multiple cylindrical osteochondral autografts.

PURPOSE: To compare 2 techniques for optimizing joint congruency for miniature osteochondral autografting in the knee: intrinsic postoperative forces acting on overdrilled autografts protruding from the femur versus alignment by a surgeon at the time of grafting. TYPE OF STUDY: Controlled animal model experiment. METHODS: A full-thickness cartilage defect was created on the weight-bearing surface of the medial femoral condyle of 13 mature sheep. Three 4.5 x 10 mm cylindrical autografts were inserted into 14-mm deep recipient holes such that the grafts were held in place by side-wall friction alone. One treatment group received grafts that were delivered flush with the surrounding cartilage and the second group received grafts that were left 2-mm proud of the joint surface. RESULTS: Three months postoperatively, the proud grafts had been repositioned by weight bearing but perigraft fissuring and fibroplasia, and subchondral cavitations were serious complications. It is suspected that these complications were caused by excessive motion between the graft and recipient site in the proud grafts. CONCLUSIONS: Grafts should be delivered flush with the joint surface when performing osteochondral transfers to avoid graft micromotion and the consequent interference with graft integration and function.

Animals↗
PubMed1999

Surgical repair of a ruptured cranial cruciate ligament in a dromedary camel.

A 14-year-old dromedary camel was examined because of lameness of the left hind limb of 3.5 months'duration. The camel injured the stifle joint when it slipped while reclining into sternal recumbency. Radiography did not reveal major abnormalities that could account for the lameness, but nuclear scintigraphy revealed increased radionuclide uptake in the left stifle joint. Intra-articular injection of anesthetic further localized the injury to the area of the left stifle joints, and arthroscopy of that joint revealed rupture of the cranial cruciate ligament. Surgical repair of the ligament was attempted, using an autogenous graft obtained from the tensor fascia lata muscle. Outcome for the camel initially was considered good on the basis of a substantial improvement in attitude, apparent increase in comfort, and decrease in lameness. The tendency for the camel to remain in sternal recumbency after surgery increased the number and severity of postoperative complications. The camel was doing well 9 months after surgery; however, it was euthanatized 16 months after surgery because of a 4-month episode of lameness. Necropsy revealed chronic osteoarthritis and bilateral rupture of the cranial cruciate ligaments.

Animals↗
PubMed1996

Development of a laboratory animal model of postoperative small intestinal adhesion formation in the rabbit.

In order to establish a model of postoperative intestinal adhesions that would simulate the problem experienced in horses, New Zealand White rabbits were utilized to compare two models of adhesion formation that had been successful in the horse, an ischemic strangulating obstruction (ISO) model and a serosal scarification model. An untreated control group was compared with animals subjected to 1, 2, 3 and 4 h periods of ISO, and to serosal scarification. At postmortem examination 14 d postoperatively, the number of rabbits in each group with adhesions was recorded. Serosal scarification was significantly more consistent at producing adhesions than ISO (Fisher's exact test, P = 0.0022). The 3 h of ISO group was significantly different from the control group: however, compared to the serosal scarification group, fewer animals had adhesions and one animal died of complications associated with the experimental procedure. Based on these results, serosal scarification was selected as the best model for utilization in further studies of adhesion prevention.

Animals↗
PubMed1996

Utilization of the serosal scarification model of postoperative intestinal adhesion formation to investigate potential adhesion-preventing substances in the rabbit.

A rabbit serosal scarification model was utilized to compare the ability of four drugs, previously administered peri-operatively to horses undergoing exploratory celiotomy, to prevent the development of postoperative intestinal adhesions. The substances compared were 32% Dextran 70 (7 mL/kg), 1% sodium carboxymethylcellulose (7 mL/kg), trimethoprim-sulfadiazine (30 mg/kg), and flunixin meglumine (1 mg/kg). The first two were administered intra-abdominally following surgery, while the latter two were administered systemically in the peri-operative period. Fibrous adhesions were evident in all animals in the untreated serosal scarification group. No significant difference in the number of animals with adhesions was found between the untreated control group and any treatment group, nor among the treatment groups. Microscopic examination of adhesions collected at postmortem examination revealed fibers consistent with cotton, surrounded by a giant-cell reaction and ongoing acute inflammation. The source of the fibers was likely the cotton laparotomy sponges used to scarify the intestinal surface, since the pattern in the granuloma and sponge fibers appeared similar under polarized light. Though consistent intestinal adhesion formation was produced in the rabbit, the presence of foreign body granulomas may prevent consideration of this model for future research. The drugs tested were ineffective in preventing the formation of postoperative small intestinal adhesions in this model.

Animals↗
PubMed1995

Geometrical properties of the ovine tibia: a suitable animal model to study the pin-bone interface in fracture fixation?

To determine whether dimensional scaling (relative to the human) is necessary for screwed pins used in externally applied fracture fixation studies on sheep, geometrical data were determined for six ovine tibiae. Each tibia was potted relative to a lengthwise reference axis and sectioned at 5 per cent length intervals over its central 80 per cent. Enlarged (280 per cent) images of each cross-section were digitized at 1 mm increments around the periphery of the periosteal and endosteal surfaces, the data were digitally filtered, and geometrical properties were computed to include cross-sectional area A, maximum and minimum second moments of area (Imax and Imin), polar second moment of area J, and effective polar second moment of area J(eff). Proportional scaling of geometrical properties with respect to bone length (L2 for A, and L4 for second moments of area) significantly (p < 0.000001) decreased the coefficient of variation in data by an average 36 per cent. From 30-90 per cent distal, J(eff) for the ovine tibia is smaller but within 7 per cent of J--in stark contrast with the human tibia, where J(eff) has been reported as 70-80 per cent of J over the same tibial length. While previous ovine studies involving external fixator pins have employed the same diameter of pin as has been used in humans (that is 5 or 6 mm), a 'first-order' approximation of the data for A, Imax, Imin and J(eff) suggests these pins should be scaled down to 4 mm and 4.75 mm respectively for use on the ovine tibia over the range 25-80 per cent distal along its length.

Adult↗
PubMed1989

Mandibular condylectomy in a horse.

Mandibular condylectomy was effective in improving mastication and stopping weight loss in a horse. The horse had a history of intermittent purulent drainage from a facial wound and unilateral ankylosis of the temporomandibular joint.

Animals↗
PubMed1988

Effects of lesion size and location on equine articular cartilage repair.

The mechanisms and completeness of equine articular cartilage repair were studied in ten horses over a nine month period. Large (15 mm square) and small (5 mm square) full-thickness lesions were made in weight bearing and nonweight bearing areas of the radiocarpal, middle carpal and femoropatellar joints. The horses were euthanized in groups of two 1, 2.5, 4, 5 and 9 months later. Gross pathology, microradiography, and histopathology were used to evaluate qualitative aspects of articular repair. Computer assisted microdensitometry of safranin-O stained cartilage sections was used to quantitate cartilage matrix proteoglycan levels. Structural repair had occurred in most small defects at the end of nine months by a combination of matrix flow and extrinsic repair mechanisms. Elaboration of matrix proteoglycans was not complete at this time. Statistically better healing occurred in small weight bearing lesions, compared to large or nonweight bearing lesions. Synovial and perichondrial pannus interfered with healing of osteochondral defects that were adjacent to the cranial rim of the third carpal bone. Clinical and experimental experience suggests that these lesions are unlikely to heal, whereas similar lesions in the radiocarpal and femoropatellar joints had satisfactory outcomes. Observations made in this study support the use of early postoperative ambulation, passive flexion of operated joints, and recuperative periods of up to a year for large cartilage defects.

Analysis of Variance↗
PubMed1987

Balloon-tipped catheter arterial occlusion for prevention of hemorrhage caused by guttural pouch mycosis: 13 cases (1982-1985).

Epistaxis, caused by guttural pouch mycosis, was treated by balloon-tipped catheter and ligature occlusion of the involved arteries in 13 horses. In 7 horses, more than one artery was catheterized. Serious postoperative hemorrhage was prevented in all horses. Long-term endoscopic follow-up examination was possible in 8 horses, and all had complete regression of the fungal lesion as early as 5 weeks after surgery. Six of the 8 horses did not receive medical treatment. Problems related to the use of the balloon-tipped catheter technique were rare. There were incisional infections in 3 horses, catheter breakage during removal occurred twice, and in one horse, a catheter was inappropriately placed.

Angioplasty, Balloon↗
PubMed1986

Arthroscopic landmarks of the equine carpus.

The radiocarpal and middle carpal joints of 4 clinically normal horses and 24 necropsy specimens were examined with an arthroscope to describe the topographic anatomy of these joints. The carpal bones of the radiocarpal joint had congruent articular surfaces in extension, but carpal flexion resulted in a stairstep between the radial and intermediate carpal bones. The variable surface anatomy, as well as the restricted synovial space and the technical limitations of the arthroscope, contributed to the need for more than one arthroscopic approach to the radiocarpal joint to ensure a thorough examination. The middle carpal joint's hinge-like biomechanics resulted in a spacious synovial cavity that was more amenable to arthroscopic examination. Careful planning was necessary to ensure that areas of interest were distant from the arthroscope-insertion site to allow the best perspective possible. The lateral approach to the middle carpal joint provided the best viewing of both facets of the intermediate and third carpal bones as well as the dorsal rim of the radial carpal bone. The medial approach did not allow complete inspection of these areas.

Animals↗
PubMed1985

Recent developments in the use of arthroscopy in cattle.

Diagnostic arthroscopy can be applied to the bovine stifle to directly visualize the menisci, cranial and caudal cruciate ligaments, the articular surfaces, and the synovium. Basic arthroscopic technique for the bovine stifle hock is described using line drawings and endophotography. Examples of joint lesions as seen through the arthroscope and at postmortem dissection are presented.

Animals↗
PubMedDate not supplied

Heterotopic transfer of fresh and cryopreserved autogenous articular cartilage in the horse.

Two 10 mm thick osteochondral grafts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. The grafts were frozen in a 7.5% DMSO solution and stored in liquid nitrogen. The horses were anesthetized again on day 14 and the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifle. A fresh graft was transferred from the right hock to the left stifle. To control for the effects of surgery, another fresh graft was transferred from the right stifle to the left stifle. The result was two grafts in each femoropatellar joint. Fresh and frozen osteoarticular autografts appeared to maintain a durable weight-bearing surface for 3 months; however, the fresh grafts were clearly superior. Frozen grafts had fewer living chondrocytes, decreased safranin-O staining, and decreased SO435 uptake. Graft stability and articular surface congruency were determining factors in the outcome of all grafts. Since the availability of osteochondral autografts is limited, further work on the use of preserved allogeneic osteochondral tissue is warranted.

Animals↗
PubMedDate not supplied

Incorporation of fresh and cryopreserved bone in osteochondral autografts in the horse.

The structural integrity of subchondral bone in fresh and frozen osteochondral autografts was investigated at month 3 in 10 horses. Two osteochondral autografts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. Grafts were frozen in 7.5% DMSO. After 14 days, the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifles. A fresh graft from the right hock was implanted in each left stifle. To control for the effects of surgery, a fresh graft was transferred from the right stifle to the left stifle. The end result was two grafts in each femoropatellar joint. Fresh and frozen bone grafts maintained a structurally intact support for the cartilage surface. Graft stability and surface congruency were determining factors in the outcome of the grafts. Incorporation of both types of graft was complete at month 3, but remodeling of the fresh grafts was more active.

Animals↗
PubMedDate not supplied

Osteochondral dowel transplantation for repair of focal defects in the knee: an outcome study using an ovine model.

OBJECTIVE: A model system was developed to objectively assess the quality of articular cartilage after surgical reconstruction of focal defects in the median femoral condyle using osteochondral dowel grafts. STUDY DESIGN: The surgical technique was developed and customized to reproducibly minimize surgical trauma and graft instability in order to improve the survival of the transplanted cartilage and the long-term integrity of the joint surfaces. ANIMALS OR SAMPLE POPULATION: 24 adult female Suffolk-Romanoff crossbred sheep. METHODS: Biomechanical creep testing, paravital staining for chondrocyte viability, histological analysis, and gross morphological analysis were performed at 3, 6, and 12 months postoperatively to compare fresh autografted osteochondral dowels with allografts that had been subject to a freezing protocol known to kill chondrocytes. The latter was used to investigate the time course of cartilage degeneration after injury. These two groups were also compared with normal unoperated control tissue. RESULTS: Biomechanical behavior, chondrocyte survival, and cartilage histology differed significantly between fresh grafts and those that had been frozen. CONCLUSIONS: Indentation testing and paravital staining were able to identify degenerative changes earlier than other methods of assessment. The technique developed here reproducibly and reliably transplanted osteochondral dowel grafts while minimizing the confounding effects of surgical trauma and graft instability. CLINICAL RELEVANCE: The technique provides both a promising surgical technique for the repair of focal defects of the medial femoral condyle and a sensitive model for the future study of cryopreservation strategies for articular cartilage.

Animals↗