Biomedical subjects
Publications and source records attributed to J A Rand.
The most frequent reasons for revision of total knee arthroplasty are loosening, instability, and abnormal axial alignment. Failure to obtain appropriate component orientation, axial alignment, and soft tissue balance predisposes the implants to loosening and failure. The use of minimally constrained prostheses and careful attention to the technique are essential. Revision surgery may be successful in approximately two-thirds of the knees.
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UNLABELLED: We compared the effects of compression-plating and open intramedullary nailing after reaming on the vascular supply to a standard fracture site, on the rate of fracture union, and on the biomechanical quality of bone after union, and on the biomechanical quality of bone after union in dogs. The proper location of a compression plate in relation to the periosteum also was investigated. Bone blood flow reached higher levels and remained elevated longer in fractures that were fixed with a rod than in those fixed with a plate. Rod-fixed fractures healed by periosteal callus, whereas plate-fixed fractures healed by endosteal callus. The fracture gained mechanical strength more slowly in the rod-fixed group than in the plate-fixed group. Subperiosteal or extraperiosteal placement of a plate revealed similar effects on bone-healing. CLINICAL RELEVANCE: Decisions to use intramedullary rods or compression plates for internal fixation of fractures should be based on knowledge of the biological effects of these procedures on blood flow at the fracture site and on the mechanical strength of the healing fracture. This study defines in quantitative terms the advantages and disadvantages of intramedullary rods compared with compression plates in the internal fixation of fractures.
Fifteen patients sustained fractures of the tibia after geometric and polycentric total knee arthroplasty. The mean follow-up after arthroplasty was 45.1 months. The chief causes for the stress fractures were axial malalignment and improper component orientation. All fifteen patients experienced loosening of the prosthesis and required revision arthroplasty for a satisfactory result. Revision at the time of diagnosis of the fracture did not adversely affect fracture healing.
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The purpose of this study was to review the authors' experiences with serial sodium Amytal (amobarbital) interviews and to compare these results with those found in the literature. A chart review of 21 patients with suspected conversion disorder evaluated by Amytal interview was conducted retrospectively. Presenting symptoms included movement disorders, focal neurologic deficits, chronic pain, "spells," and pseudoseizures. The serial Amytal interviews confirmed the presence of psychopathology noted on admission and revealed underlying psychosocial stressors. In 2 of 21 patients, agents other than Amytal were used after the first interview. This series confirms that the serial Amytal interview has utility in the clinical setting as a diagnostic and therapeutic tool.
Eleven patients who were treated for talonavicular arthrosis with a talonavicular arthrodesis between 1961 and 1979 at the Mayo Clinic have been reviewed. Follow-up from surgery ranged from 2.5 to 21 years with a mean of 9.5 years. Clinical, radiographic, and gait analyses were obtained. All patients had satisfactory pain relief, but all noted difficulty in ambulating on irregular ground. Three patients had roentgenographic evidence of arthrosis affecting other tarsal joints that had not been involved before arthrodesis. Gait analysis revealed decreased terminal stance-phase plantarflexion and pronounced reduction of subtalar motion. Talonavicular arthrodesis does give predictable union and patient satisfaction but results in limitation of subtalar motion and loss of stance-phase plantarflexion.