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This study was designed to examine the attachment and reactions of soft tissues to sol-gel-derived TiO2 coatings. In the first experiment, TiO2 coated and uncoated titanium cylinders were placed subcutaneously into the backs of rats for 3, 11 and 90 days. Tissue response and implant surfaces were characterized with routine light microscopy and scanning electron microscopic (SEM) analysis. In the second experiment, TiO2-coated and uncoated discs were implanted subcutaneously into the backs of rats for 14 and 21 days. The discs were pulled out from the implantation sites with a mechanical testing device using a constant speed of 5 mm/min. Rupture force was registered, after which the discs were assigned for SEM and transmission electron microscopic (TEM) analysis. All the coated implants showed immediate contact with the surrounding soft tissues without a clear connective tissue capsule. Significantly better soft tissue response was measured for all the coated compared to the uncoated cylinders (p<0.01). Higher rupture forces were measured for all coated discs, although the differences were not statistically significant. An immediate and tight connection between connective tissue fibroblasts and coatings was noticed in TEM analysis. Our study indicates that TiO2 coatings improve soft tissue attachment on a titanium surface.

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We reviewed 19 patients who presented with aggressive granulomatosis around the femoral stem after hip replacement. All had experienced stress pain and had required revision arthroplasty on average 8.8 years after the primary operation. Fifteen patients were men and four were women; none had rheumatoid arthritis. One patient had an uncemented Moore hemiprosthesis; the others all had cemented total hip replacements. When first detected, the granulomatous lesions were multifocal in 13 patients. The first granuloma was in the region of the lesser trochanter in 10, and near the tip of the stem in only two. Speed of growth varied but on average there was doubling of the area on anteroposterior films in 2.2 years (range 6 months to 4.6 years). Aggressive granulomatous lesions in replaced hips are a distinct condition, different from simple loosening or infection; the lesions may grow rapidly, so revision surgery is indicated soon after diagnosis.

Of 155 institutionalized epileptics, 16 (10%) were noted to have suffered from different kinds of fractures when observed over a period of 1 year. The patients with fractures were further investigated with respect to blood and urine chemistry and bone morphology. The serum and urinary calcium values were below the average values for the population. Elevated values for serum alkaline phosphatase and for immunoreactive parathyroid hormone were found in most patients. The values of serum phosphate were distributed close to those of the normal population, while the urinary phosphate values were lower. Examination of bone biopsies revealed a significantly increased amount of osteoid and a significantly increased osteoclastic resorptive activity in epileptics, compared with age-matched controls. Furthermore, a slightly diminished volume of trabecular bone was noted. The high incidence of fractures may be explained by bone disease--a combination of osteoporosis, osteomalacia, and hyperparathyroidism due to chronic treatment with anticonvulsant drugs.