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  • Author or Editor: Sharon Stevenson x
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Summary

The biocompatibility and osteoconductive properties of biocompatible osteoconductive polymer (bop), a synthetic implant, were evaluated. Bilateral oval cortical defects (1 × 2 cm) were made in the lateral subtrochanteric area of the proximal portion of the femur in 16 dogs that later were treated with bop fiber (n = 16) or autogenous cancellous bone (n = 11), or were not treated (n = 5). The bop block was attached extraperiosteally to the proximal portion of the humerus in 6 dogs. Radiographic assessment of surgery sites was performed at 4-week intervals, and histologic evaluation was performed at 4, 8, 16, and 24 weeks after surgery. Radiographic signs of bone healing were not observed in defects treated with bop fiber. Defects treated with cancellous bone or not treated had radiographic signs of progressive bone ingrowth. Radiographic evidence of periosteal new bone formation near control and bop-treated defects was observed 4 weeks after surgery; increased periosteal reaction was associated with bop fiber. This new bone had resorbed by week 24, except bone adjacent to bop fiber, where continued periosteal reaction was apparent. Histologic evidence of bone formation was observed extending to, but not incorporating, bop fibers. The bop fibers became surrounded by a fibrous capsule, and fibrovascular connective tissue infiltrated between and into bop fibers, but minimal bone formation incorporated the bop material during the follow-up period. During that time, active periosteal new bone formation was evident adjacent to the bop fibers. Defects treated with cancellous bone or not treated healed by ingrowth of cancellous bone during the first 12 weeks after surgery and by reformation of the lateral cortical wall by week 24. The bop blocks became surrounded by a fibrous capsule, but connective tissue or bone ingrowth into bop blocks was not observed. Results indicate that bop is not osteoconductive within a 6-month time frame when used in subtrochanteric femoral defects or when placed extraperiosteally on the proximal portion of the humerus of clinically normal dogs.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To compare the biochemical, histochemical, and immunohistochemical profiles of articular cartilage from horses with naturally acquired distal tibial osteochondrosis (OC) with cartilage from a similar location in clinically normal horses.

Animals

9 affected horses (group 1, 16 OC lesions) and 4 control horses (group 2, 8 normal osteochondral specimens).

Procedure

OC specimens were collected during arthroscopic removal of the fragment, and control specimens were collected by aseptic osteotomy. Uronic acid, total protein, total glycosaminoglycan (GAG), chondroitin sulfate (CS), and keratan sulfate (KS) contents were determined. Histomorphologic, histochemical, and immunohistochemical examinations were performed on specimens after snap freezing at −80 C and cryosectioning. Monoclonal antibodies (MAB) 3B3 and 5D4 were applied for location of epitopes of CS and KS, respectively.

Results

OC lesions had significantly lower quantity of uronic acid, total GAG, and CS, compared with normal cartilage. OC cartilage had significantly less intense staining with toluidine blue, along with irregular cellularity and tidemark characteristics, compared with normal cartilage. Monoclonal antibodies 3B3 and 5D4 stained OC cartilage, whereas MAB 5D4 did not stain control cartilage. Additionally, MAB 3B3 and 5D4 stained the fibrous tissue that was found firmly attached to the OC lesion located between the parent distal portion of the tibia and OC fragment.

Conclusion

OC cartilage lesions of the distal intermediate ridge of the tibia in horses are biochemically, histochemically, and immunohistochemically distinct from normal cartilage from the same location. Results may reflect the inability of the chondrocyte of the developing joint to alter matrix components that would allow proper maturation and differentiation into bone. (Am J Vet Res 1997;58:89–98)

Free access
in American Journal of Veterinary Research

Summary

Bilateral midbody hemimandibular osteotomies were performed between premolars 3 and 4 in 18 adult dogs. Hemimandibles were repaired by use of monocortically applied bone plates (n = 6), an interdental fixator composed of an Erich arch bar and acrylic (n = 6), or a type I external skeletal fixator (n = 6). At the immediate postoperative evaluation, hemimandibles stabilized with interdental fixators had an osteotomy gap distance (mean ± SEM, 1.6 ± 0.2 mm) that was significantly (P < 0.05) greater than for hemimandibles stabilized with external skeletal fixators (1.2 ± 0.3 mm). Osteotomy gap distance of hemimandibles stabilized with external skeletal fixators (1.5 ± 0.2 mm) was significantly (P < 0.05) greater at weeks 4 (1.1 ± 0.2 mm) and 8 (0.8 ± 0.3 mm) after surgery than the osteotomy gap distance of hemimandibles stabilized by application of bone plates. By week 16, significant differences in osteotomy gap distance were not detected between groups. Immediately after surgery, mandibular alignment measurements were not significantly different for dogs with bone plates (0.3 ± 0.1 mm), interdental fixators (0.3 ± 0.1 mm), and external skeletal fixators (0.9 ± 0.5 mm). Mandibular alignment scores were not significantly different between treatment groups during the remaining postoperative period. Occlusal measurements were not significantly different between evaluations performed before surgery and 16 weeks after surgery, regardless of treatment group. Radiographic evidence of healing in hemimandibles stabilized with external skeletal fixators was significantly (P < 0.05) less at 4 and 8 weeks, compared with hemimandibles stabilized with bone plates and interdental fixators; however, radiographic evidence of bone healing was not significantly different between fixation groups at 16 weeks. Radiographic evidence of implant loosening was seen in 1 of 12 (8%) hemimandibles receiving bone plates, 1 of 12 (8%) hemimandibles receiving interdental fixators, and 4 of 12 (33%) hemimandibles receiving external skeletal fixators. Periosteotomy callus was radiographically evident in 11 of 18 (61%) hemimandibles at 4 and 8 weeks only, but significant differences in periosteotomy callus surface area were not detected between groups. Of 24 hemimandibles stabilized with interdental and external skeletal fixators, 22 (92%) had callus formation that progressively matured into trabecular bone by 16 weeks. At 4 weeks, bone healing characterization scores of hemimandibles stabilized with bone plates were significantly (P < 0.05) less than (ie, had greater stability) bone healing characterization scores of hemimandibles stabilized with interdental and external skeletal fixators, but at 8 and 16 weeks, bone healing characterization scores between treatment groups were not significantly different. Histopathologic or radiographic evaluation did not reveal evidence of pulp disease or pathologic changes of teeth, which would have been associated with root resection at the osteotomy site, application of acrylic to the crown surface, or placement of external fixator pins and cortical screws. On the basis of the fact that the dogs appeared clinically normal and were able to masticate, analgesics were discontinued by 24 hours after surgery. Analysis of data indicated that an interdental fixator composed of an Erich arch bar and acrylic may be a viable method for fracture repair of mandibles.

Free access
in Journal of the American Veterinary Medical Association