Bovine bone screws: metrology and effects of chemical processing and ethylene oxide sterilization on bone surface and mechanical properties.

We assess the effects of chemical processing, ethylene oxide sterilization, and threading on bone surface and mechanical properties of bovine undecalcified bone screws. In addition, we evaluate the possibility of manufacturing bone screws with predefined dimensions. Scanning electronic microscopic images show that chemical processing and ethylene oxide treatment causes collagen fiber amalgamation on the bone surface. Processed screws hold higher ultimate loads under bending and torsion than the in natura bone group, with no change in pull-out strength between groups. Threading significantly reduces deformation and bone strength under torsion. Metrological data demonstrate the possibility of manufacturing bone screws with standardized dimensions.

Overcorrection during treatment of pectus deformities with DCC orthoses: experience in 17 cases.

Treatment of pectus carinatum and pectus excavatum with dynamic chest compressor (DCC) orthoses have been reported by Haje and others. The goal of this study was to demonstrate that overcorrection during orthotic treatment of children and adolescents with pectus deformities can occur and requires medical attention. Of 3,028 children and adolescents with pectus deformities, observed between 1977 and October 2005, 1,824 were prescribed treatment with DCC orthoses and, after a few months of treatment, some overcorrection was noted in 30 patients. Of the patients who received orthoses, 738 had a minimum follow-up of 1 year and 17 of these, 2 with pectus excavatum and 15 with pectus carinatum, presented overcorrection and were studied. The dynamic remodeling method (DCC orthoses + exercises) was applied. The procedures, adopted according to each patient's needs, were: decreasing the time of orthosis wear and/or the tightening of the screws, introducing a second orthosis, and improving the prescribed exercises and/or encouraging the patient to perform them more intensively. The therapy was successful in all patients, and the result was maintained in one case of pectus excavatum followed up until adulthood. It was concluded that overcorrection during DCC orthosis wear can occur and that careful medical follow-up is necessary if this complication is to be successfully reversed.