Porous titanium is a kind of new biomaterial. After being implanted into the bone, the ingrowth of the bone was demonstrated. This ingrowth of bone tissuse was thought to be beneficial to fixation of a prosthesis and filling of a bone cavity.In this study, the porous sample was abtained from sintered amorphous titanium powder, with the mean size of pores larger than 150? in diameter, and the porosity in the range of 45-47%. It was implanted into the femurs of rabbits and dogs, and specimons were taken for examination 2, 4, 6 and 12 weeks after operation.It was shown that the shear strength of the samples at the implant bone surface was 7.51kg/cm2 2 weeks after surgery. It was demonstrated that bone tissue had begun to grow into the meshwork 2 weeks after surgery, and deeper penetration was seen after 4 weeks. Scanning electron microscopy was done to show the appearance of bony growth into the meshwork. Bony growth was verified by x-ray diffraction scan analysis for calcium. Bone ingrowth could be seen in the majority of the interstices of the meshwork 12 weeks after surgery. Bone lacuna and tubules could be seen when stained with silver nitrate. The deepest penetration of bone ingrowth was 1400?. There was no obvious tissue reaction or formation of fibrous membrane.The use of the porous material may help to prevent loosening of a prosthesis. It is believed that porous titanium we used possesses the characteristics that a porous material should possess. Further research should be done to ascertain its clinical usefulness.

The repair of severed tendons within the digital sheath constitutes a complicated surgical problem. The injury and adhesion of the tendons are an important factor for functional return in the hand. On the basis of experimental study, 7 cases of injuries of flexor digitalis tendons have been treated by using silastic artificial tendons since 1982. During the operation the tendon graft was ensheathed in a porous filmy silastic tube, including the sites of anastomosis. This technique can prevent adhesion between tendon and its surrounding tissues. The operation can be performed in one stage. The operative procedure and its indication, reconstruction of the pulley system and the gliding function of the tendon were discussed.

[Objective]The purpose of this study was to describe mid report the result of the ulnar nerve transfer to biceps muscle to restore elbow flexion after acute and delayed upper brachial plexus injuries.[Methods]Two patients with acute brachial plexus injury (the time between the injury and the operation were six and eight months) and three patients with delayed brachial plexus injury(the time between the injury and the operation were from twevle to eighteen months) underwent nerve transfer using fascicles of the ulnar nerve to the motor branch of the biceis muscle. The average age of the patients was twenty eight and the mean follow-up periods were nine months after the surgery. Patients were evaluated with regard to reinnervation of the biceps, ulnar nerve function, elbow flexion strength, and grip strength.[Results]For the two acute patients, the first sign of biceps muscle contraction were observed within 1 week, the average time required for reinnervation of the biceps after nerve fascicle transfer was within six months. For the three delayed patients, the first sign of bicep muscle contraction was observed in about three month, and the average time required for reinnervation of the biceps was ten months.Hypoesthesia of the ulnar nerve was clinically abserved in three patients, but this symptom disappeared within month with no treatment.Compared with those delayed cases, the acute patients had faster and better recovery of their olbow flexion function.However, all patients achieved grade-3 or better elbow flexion strength according to the grading system of the Medical Research Council.[Conclusion]The author recommend this safe, simple and effective Oberlin procedure for brachial plexus injuries involving the C5、6 or C5~7 nerve roots.

This study aims at the mechanism of foveola formation in bovine trabecular bone under fatigue process and its relation with biomechanical pathogenesis of senile osteoporosis. The scanning electron microscope equipped with fatigue stage was used to observe fatigue micro injury accumulation of cancellous bone. The massive foveola formation in the laminal bone of vertical trabeculae was found in the tensile fatigue test. There existed the collagen avulsion in the foveola. The massive foveola formation was also observed in the lamina bone of the horizontal trabeculae in the compressive fatigue test. The bone collagen fibers were protracted, debound with hydroxyapatite crystal, and then avulsed under tensile and bending stresses. Finally the retraction of the avulsed collagen fibers brought on the massive formation of foveolae in lamina bone. The mechanical capacity of bone also declined greatly. We infer that the direct mineralization of avulsed collagen and foveola in lamina bone would be one of the main processes of self repair in vivo, which brings on the increase in fragility and stiffness of trabeculae of senile osteoporotic bone along with the agelong accumulation of collagen fatigue injury and foveola formation in the lamina bone.
Animals ; Bone and Bones ; pathology ; ultrastructure ; Cattle ; Collagen ; ultrastructure ; Compressive Strength ; Durapatite ; chemistry ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Models, Biological ; Stress, Mechanical ; Tensile Strength