Evaluation of the Bactericidal and Fungicidal Activities of Poly([2-(methacryloyloxy)ethyl]trimethyl Ammonium Chloride)(Poly (METAC))-Based Materials.

Poly([2-(methacryloyloxy)ethyl]trimethyl ammonium chloride) (METAC) and the gels were prepared and evaluated for their bactericidal and fungicidal activities. The antimicrobial properties of poly(METAC) were tested against Escherichia coli (E. coli), Bacillus subtilis (B. subtilis), Saccharomyces cerevisiae (Sa. cerevisiae), methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans). Moreover, the structural forms of the linear and cross-linked poly(METAC) were investigated for their influences on bacterial aggregation, precipitation, and cell-death. To our knowledge, this is the first report on the comparison of the antimicrobial properties of poly(METAC) and poly(METAC)-gels. The bactericidal and fungicidal activities were evaluated by determining minimum inhibitory concentrations (MICs), UV⁻Vis spectroscopy, and fluorescence and confocal microscopies. The MICs were found to be 123 (MSSA), 123 (MRSA), 123 (P. aeruginosa), 370 (E. coli), 123 (B. subtilis), 370 (C. albicans), and 370 µg/mL (Sa. cerevisiae), as determined by broth dilution, and 370 (MSSA), 370 (MRSA), 370 (P. aeruginosa), 3300 (E. coli), 370 (B. subtilis), 1100 (C. albicans), and >10,000 µg/mL (Sa. cerevisiae), as determined by paper disc diffusion (on solid medium). The poly(METAC)-gels achieved rapid adsorption/precipitation of bacteria via the cationic surface charge. Thus, these poly(METAC)-based polymers can potentially be used as antibacterial materials.

Disassembly of a modular femoral component after femoral head prosthetic replacement.

We report a rare case of a taper-locked femoral inner head that have been completely separated from the stem neck. A 76-year-old man who had hip fracture of the right hip had disassembly of inner head and stem neck after revision of bipolar hip prosthesis. This force could have been amplified by the pumping phenomenon generated after the revised inner head. We suspect the sealed air pushes back the stem neck, and unlocks the taper lock of the inner head, causing separation of the stem neck from the inner head. To prevent pumping phenomenon, we recommend manual testing of the taper lock to confirm that it has been assembled correctly and its integrity before implantation when the bloody and fatty membrane is adequately removed from stem neck.

Risk factors for hip fracture in Japanese elderly women with osteoporosis: applicability of biochemical markers in bone turnover.

AIM: The purpose of this study was to investigate risk factors for hip fracture in 169 Japanese elderly women. METHODS: Patients were divided into three groups: 53 patients had osteoporosis with hip fractures (FX-G), 59 patients had osteoporosis without hip fractures (NFX-G) and 57 patients had low back pain with neither osteoporosis nor hip fracture (NOP-G). Bone mineral density (BMD) of lumbar spine, bone-specific alkaline phosphatase (BAP) and deoxypyridinoline (DPD) were compared among the three groups. RESULTS: The mean BMD of FX-G and NFX-G was lower than that of NOP-G, but there was no significant difference between FX-G and NFX-G. Although the mean BAP of FX-G was similar to that of NOP-G, both were lower than NFX-G (P < 0.05). However, the mean DPD of FX-G was higher than the other groups (P < 0.05, vs NFX-G, P < 0.001, vs NOP-G). The percentage of patients who showed BAP levels less than 35 IU/L and DPD levels of 7.5 nmoL/mmol-Cr or more, was highest in FX-G (72.7%). This percentage was lower for NFX-G (30.9%) and NOP-G (16.4%). The odds ratio of hip fracture occurring was 5.77 (95% confidence interval, 2.25-14.66). CONCLUSION: Bone turnover consisting of increase in bone resorption and decrease in bone formation apart from BMD of lumbar spine resulted in a higher incidence of hip fracture for Japanese elderly women with osteoporosis.

Minimum 10-year radiographic follow-up of a cementless acetabular component for primary total hip arthroplasty with a bulk autograft.

We radiographically investigated 36 hips in 34 patients with osteoarthritis of the hip who had undergone total hip arthroplasty. Their mean age was 59.2 years (range 36-79 years), and the mean follow-up period was 11.2 years (range 10-14 years). The long-term outcome and the chronological changes in the bulk autograft were examined. The acetabular component of the prosthesis was a Lord-type threaded cup with a smooth surface. At follow-up, bone absorption was minor in 17 joints, moderate in 11, and major in 8. The hips with graft coverage of >==20% (group A) had a significantly higher loosening rate than hips with coverage of <<20% (group B) ( P << 0.05). The cup position changed markedly in group A. Our findings indicate that graft coverage should be less than 20% when a bulk graft is used together with a smooth-surfaced cementless cup.