Surface-modified nanoparticles as a new, versatile, and mechanically robust nonadhesive coating: suppression of protein adsorption and bacterial adhesion.

The synthesis of surface-modified silica nanoparticles, chemically grafted with acrylate and poly(ethylene glycol) (PEG) groups, and the ability of the resulting crosslinked coatings to inhibit protein adsorption and bacterial adhesion are explored. Water contact angles, nanoindentation, and atomic force microscopy were used to characterize the cross-linked coatings. Coatings showed a high degree of hydrophilicity combined with a remarkable hardness and stiffness in the dry state. Adsorption of the small protein lysozyme from buffer solution on coated silica wafers decreased significantly with increasing grafting density of the PEG groups on the nanoparticles and was completely inhibited at 0.6 chains nm(-2). Coatings significantly reduced adhesion of Staphylococcus epidermidis HBH 276 in a parallel plate flow chamber with respect to bare glass (>90%), whereas adhesion of Pseudomonas aeruginosa AK1 was only marginally affected by the presence of the coating (<15%). Passage of an air-bubble resulted in almost complete detachment (>93%) of both strains from coated glass, indicating that the adhesion strength between both bacterial strains and the coated surface was significantly reduced by the grafted PEG groups. These coatings thus provide a new method to prepare mechanically robust films with nonadhesive properties that will be extremely useful for the design of biocompatible surfaces in biomedical applications.

Retrospective direct comparison of three intraarticular anterior cruciate ligament reconstructions.

A long-term retrospective study (minimum 5 years) was done looking at three groups of anterior cruciate deficient knee patients using both subjective and objective anterior cruciate tests. Twenty-seven chronic anterior cruciate ligament deficient knees reconstructed with the middle third of the patellar tendon and 28 chronic anterior cruciate ligament deficient knees reconstructed with the semitendinosus tendon were included in this consecutive group of patients and were felt to be directly comparable. It was found that the chronic anterior cruciate ligament deficient group reconstructed with the semitendinosus tendon had 4 excellent, 10 good, 7 poor, and 7 failures with an objective score averaging 4.5 of a possible 12, while the comparable group reconstructed with the middle third of the patellar tendon had 16 excellent, 7 good, 3 poor, and only 1 failure with a score of 10 of a possible 12 (P less than 0.0032). For completeness sake, 20 anterior cruciate deficient knees from this group of consecutive patients that were reconstructed acutely with the semitendinosus tendon were also examined. This group had 8 excellent results, 9 good, 3 poor, and no failures with a score of 9.8 (P less than 0.03 compared to the other group using the semitendinosus tendon). This comparison between the two groups where the semitendinosus tendon was used in the anterior cruciate ligament reconstruction was made only to show the difference between studies dealing with knee reconstructions. There may be a significant difference between a study dealing with acutely reconstructed knees versus one focusing on chronically reconstructed knees, most likely because of both patient selection and time between injury and reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

The results of extensor mechanism realignment following failed lateral retinacular releases.

An evaluation of open extensor mechanism realignments performed in patients with previously failed lateral retinacular releases was performed. A 76 per cent and 66 per cent good to excellent objective and subjective result was found in this study. Radiography, muscle power determinations, failure determinations, and complications are discussed.

Aspergillus discitis. Report of two cases and review of the literature.

Aspergillus discitis is a rare disease that usually occurs in immunocompromised hosts. In the one case reported in the orthopedic literature surgical debridement was required. Two additional cases, which occurred in intravenous drug abusers, are reported here. One case is unique in the orthopedic literature in that eradication of the disease occurred with chemotherapy alone.