Biomedical subjects

T V Swanson

Publications and source records attributed to T V Swanson.

4 recordsLinked to original sources

PubMed1993

Effects of partial patellectomy and reattachment of the patellar tendon on patellofemoral contact areas and pressures.

We used a previously reported experimental method to measure patellofemoral contact areas and pressures in four pairs of human cadaveric knees before and after a partial patellectomy. The knee joints were loaded by application of a flexion moment, which was resisted by the extension moment of the quadriceps mechanism. Patellofemoral contact was measured with the use of pressure-sensitive film, at 30, 60, and 90 degrees of flexion of the knee. Partial patellectomy decreased the patellofemoral contact area and increased pressure. We observed alterations in the patterns of contact, including a proximal shift in patellofemoral contact, after partial patellectomy. An anterior reattachment of the patellar tendon significantly minimized the effects of 20 and 40 per cent patellectomies (p < 0.05). After a 60 per cent patellectomy, patellofemoral contact was altered markedly, with the contact area reduced to less than 50 per cent of the control values regardless of the position of the patellar tendon reattachment.

Adult↗

PubMed1992

Fractures of the talar neck. A mechanical study of fixation.

Anatomical reduction and rigid internal fixation of fractures of the talar neck allow early mobilization of the ankle and subtalar joints. Forty fresh tali from cadavera were fractured across the talar neck and were internally fixed with one of four methods. The specimens were again loaded to failure, and mean yield loads, yield deformations, stiffness, and energy absorbed were compared. The two configurations of screws that were inserted posterior to anterior provided yield loads superior to those of screws inserted anterior to posterior. All combinations of screws were stronger than Kirschner wires. Comparisons of yield deformations, stiffness, and energy absorbed corroborated these results. The calculated theoretical maximum shear force across the talar neck during active motion was 1129 newtons. This exceeded the strength that was provided by Kirschner wires and anteriorly inserted screws but not that provided by screws that were placed posteriorly.

Adolescent↗

PubMed1991

Open hand fractures: prognosis and classification.

Two hundred open fractures distal to the carpus in one hundred twenty-one patients were studied retrospectively. One hundred seventy-three fractures were followed-up to complete bony union, which occurred at a median period of seven weeks. Ninety-seven total complications included nine wound infections in seven patients, eighteen malunions, seventeen delayed or nonunions, twenty-three fixation problems, and two late amputations. Infection rate increased in the presence of wound contamination, delay in treatment greater than twenty-four hours, or systemic illness. It was not increased by presence of internal fixation, immediate wound closure, large wound size, tendon/nerve/vascular injury, or high-energy mechanism. We suggest a classification predictive of infection: type I: Clean wound and no systemic illness; type II: Contaminated wound, delay in treatment greater than twenty-four hours, or significant systemic illness. We recommend choosing fracture stabilization on the basis of the mechanical needs of the fracture, regardless of wound size, injury energy, or contamination. Immediate wound closure is appropriate for type I injuries and delayed closure should be reserved for type II wounds.

Adolescent↗

PubMed1988

Kidney size at diagnosis of childhood acute lymphocytic leukemia: lack of prognostic significance for outcome.

The prognostic significance of kidney size at diagnosis of acute lymphoblastic leukemia (ALL) was assessed in a population of 142 children. Kidney size was determined using three different methodologies, and its significance was determined by univariate and multivariate life-table methods. Enlarged kidney size (as determined by any of the three methods used) was not associated with an overall poorer survival. These findings were consistent when kidney size at diagnosis was analyzed as a singled variable and when it was considered after adjustment for the known prognostic factors of age, sex, and initial WBC count. Assessment of renal size at the time of diagnosis of childhood ALL is not indicated for the purpose of predicting subsequent prognosis.

Age Factors↗