Purpose: To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + β-tri-calcium phosphate (β-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery.Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/β-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions:The inclusion of β-TCP favors screw degradation since the PDLLA/β-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/β-TCP screws presented less bone tissue at the implantation site.

Background: The management of malunion of pelvic fracture and its complications may require from conservative to surgical methods, depending on the severity and temporal evolution. Thus, the aim of this present report is to describe the treatments adopted in a cat with severe pelvic stenosis.Case: An approximately 3-year-old neutered male crossbreed cat, weighing 3 kg, was presented due to difficulty in defecation in the previous eight months. According to its tutor, the cat was adopted one year earlier, with a history of pelvic fracture due to a run over, which had been treated conservatively. The tutor also mentioned that since the appearance of dyschezia, the cat had only been treated with enemas, but without success. In abdominal palpation, there was presence of pain and a mass of firm content in descending colon topography. The radiographic examination of the pelvis presented an exuberant bone callus, characterizing an old fracture, a consolidation with change of bone axis in the right ischium, together with megacolon and fecaloma. It was initially decided that a liquid glycerin-based enema would be performed, in conjunction with clinical treatment with administration of cisapride, dimethicone and lactulose. Although the medical treatment initially helped improve the clinical picture, the cat presented fecaloma two months later. Surgical treatment was then performed, in which distraction of the pubic symphysis with use of a heterologous cortical bone graft (canine tibia stored in glycerin 98%) was performed, as the tutor was not favorable to colectomy as the first option. However, after one month of intervention, despite good evolution, the animal again showed signs of dyschezia. At this point the tutor agreed to colectomy, which was subtotal with preservation of the ileocolic valve.Discussion: The initial treatment of the cat in this report, with administration of prokinetic, antifoaming agent and laxative was insufficient, as the cat again developed fecaloma after two months of use of such medications. In general, cats presenting dyschezia, with constipation and megacolon over a period of more than 6 months, may present irreversible lesion due to damage to the smooth muscle of the colon, with presence of hypertrophy and neuromuscular degeneration of the organ. The problem had already been explained to the tutor, who preferred the medical treatment, as until then the cat had only been treated with enemas. Several techniques have been used to promote the widening of the pelvic canal, including the pelvic symphysiotomy and use of spacers. Although the autograft stimulates osteogenesis more rapidly, there is difficulty in obtaining bones of adequate size and strength, one of the reasons why the heterologous bone was used in the present case. Even with adequate widening of the pelvic canal, the lesion’s evolution over time may have predisposed to irreversible damage of the colon in this case. Among existing techniques for resolution of megacolon in cats, coloplasty, partial colectomy, and subtotal colectomy can be cited. The latter technique was undertaken in the present case, in conjunction with ileocolic junction preservation, which has the advantage of a lower incidence of diarrhea. Thus, thesigns of dyschezia had ceased. In conclusion, the combination of procedures adopted for distraction of the pelvic symphysis and subsequent subtotal colectomy allowed adequate recovery of the animal without relapses during a follow-up period of five years. The use of the heterologous graft (canine tibia) for distraction of the pelvic symphysis behaved as a spacer of adequate size and resistance.

Objective The aim of this study was to evaluate the influence of near-cortical over-drilling holes on the mechanical behaviour of locking plate constructs applied in maned wolf's femur by using mechanical testing and finite element method (FEM). Study Design Seven pairs of adult maned wolves (Chrysocyon brachyurus) femur bones were randomly distributed into four groups. In all groups, a 3.5 mm locking compression plate, designed with 12 combi-holes and one locked, was applied to the lateral surface of the femur. G1 (n = 4) received bicortical locking screws placed in holes 1, 3, 5, 8, 10 and 12. In G2 (n = 5), the plate was applied as used in G1, but the application of the locked screws involved the near-cortical over-drilling technique. In G3 (n = 4), the plate was applied as used in G2, but the size of the near-cortical over-drilling was larger. The combi-holes 6 and 7 were maintained over a 10 mm fracture gap without screws. All constructs were tested for failure in the axial load. The axial load was applied eccentrically to the femoral head. Results Statistical differences were observed in the maximum load with G3 > G1 and G3 > G2, and in the deflection with G2 > G1 and G2 > G3. The FEM showed the lowest total displacement of the bone-plate constructs as well as of the plate in G1 compared with G2 and G3. Conclusion The near-cortical over-drilling technique used in unstable fractures induced in the maned wolf's femur showed by static axial compression test that maximum load and deflection are dependent on drill hole size induced in the near-cortex. Based on FEM, the lowest total displacement of the bone-plate constructs was observed in Group 1.