ABSTRACT
Polyvinyl Alcohol (PVA) hydrogel plugs were implanted in artificial osteochondral defects on the trochlear groove of rat knees. After 0, 3, 6, 12, and 24 weeks of followup, samples containing the implants were mechanically evaluated by creep indentation test, chemically, and histologically by optical microscopy. The mechanical test pointed towards an increase of the implant creep modulus and the chemical analysis exhibited an increasing concentration of calcium and phosphorus within the implants over time. Optical microscopy showed no foreign body reaction and revealed formation, differentiation, and maintenance of new tissue at the defect/implant interface. The absence of implant wear indicated that the natural articular lubrication process was not disturbed by the implant. The performance of the irradiated and acetalized PVA was considered satisfactory for the proposed application.
ABSTRACT
Stainless steel plugs coated with and without Al2O3, TiO2 and Nb2O5 were inserted into canine femora in order to develop a methodology of rapid identification of appropriate specimens for deeper analysis of implant-bone interfaces. This approach is especially meaningful in areas where research funds are scarce. After a maximum follow-up period of 52 wk, bone segments containing plugs were radiographed using conventional techniques, high resolution techniques (which allowed a good preliminary evaluation) and microradiography. Analysis by X-ray fluorescence spectrometry indicated release of the materials by the implants. Microdensitometry of the microradiographs allowed a precise thickness determination of the tissue formed around the implants.
