Biomedical subjects
K E Marks
Publications and source records attributed to K E Marks.
Patella alta and chondromalacia.
The Insall-Salvati method of determining the position of the patella by radiography was employed in fifty-one patients with chondromalacia patellae that had been proved at arthrotomy. There was no definite relationship between chondromalacia patellae and patella alta. There was, however, a highly significant statistical difference between the ratio of the length of the patella to that of the patellar tendon in normal men and women.
Mechanical strength of acrylic bone cements impregnated with antibiotics.
Admixing of several antibiotic powders which were insoluble in methyl methacrylate did not decrease the compressive and diametral tensile strengths of two acrylic bone cements when tested after setting for 1 day and after leaching 40 days in water at 37 degrees C. When antibiotics were added as water solutions, the included water resulted in a significant decrease in these bulk mechanical properties. Storage in water for 40 days caused surface irregularities only on specimens of the set antibiotic admixtures. Approximately 0.5% of the admixed dosage of these water-soluble antibiotics could be leached from the set cements. The observed surface channels, presumably left by the loss of antibiotic, suggest further study of surface-sensitive mechanical properties may be needed. The bulk mechanical strengths presented here are conclusive only for the particular combinations of antibiotics and cements investigated, and should not be generalized at this time to any or all antibiotic admixtures or other mechanical properties.
Antibiotic-impregnated acrylic bone cement.
In vitro and in vivo experiments were performed to study the antibacterial and mechanical properties of Simplex and Palacos acrylic bone cements utilized for the production of acrylic cement-antibiotic composites. Acrylic cement without antibiotic had no bacteriostatic effect on Staphylococcus aureus, Escherichia coli, and Pseudomonas. Oxacillin, cefazolin, and gentamicin are stable in acrylic cement and are released in a microbiologically active form. The three antibiotics diffused from the Palacos in larger amounts daily and for a significantly longer time than from the Simplex. Mechanical tests demonstrated that admixture of antibiotics and acrylic cement had no influence on the compressive and diametral tension strengths of the cement. Bacteriostatic concentrations of oxacillin in wound hematomas were measured for fourteen days after implantation of an oxacillin-Simplex composite in dogs. High bactericidal concentrations of the antibiotic were measured in the surrounding bone for twenty-one days after implantation.
Effects of visual cortical lesions upon ambulatory and static localization of light in space.
Explore the source record for details and available documents.
Antibiotic-impregnated acrylic bone cement.
Explore the source record for details and available documents.
Revision of Mueller total hip arthroplasties.
Experience with 65 revisions of Mueller total hip arthroplasties and a minimum of two years follow-up on 32 revised total hips showed that the results appear to be poor in a significant number (22%) of patients: 18% required additional surgery. Revision of total hip arthroplasties with recementing of one or both components carries a significant risk of intraoperative and postoperative complications. Since the introduction of femoral components with improved metallurgic properties, no stem failures have occurred. Varus position of the femoral stem predisposes for stem loosening. Aspiration arthrography is of limited value in the evaluation of a painful total hip. In cases of femoral component loosening with gross cystic changes on the roentgenograms, early revision is recommended as fracture of the femoral shaft may ensue. Late loosening of the acetabular cup as yet appears to be an uncommon cause of total hip arthroplasty failure. Attention to the details of surgical technique and more research on material selection in primary total hip replacement are important.