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Biomedical subjects

A Unsworth

Publications and source records attributed to A Unsworth.

At least 91 records · Page 5Linked to original sources
PubMed1986

Measurement of stiffness in the metacarpophalangeal joint: the effects of physiotherapy.

Five common modes of physiotherapy were applied to a group of normal subjects and to a group of patients with rheumatoid arthritis. The metacarpophalangeal joint stiffness was measured before therapy and immediately afterwards and the results compared. The only statistically significant result was that short-wave diathermy and ultrasound both reduced the amount of energy dissipated in the joints of the patients. No significant changes occurred in the normal group.

Arthritis, Rheumatoid↗
PubMed1984

Measurement of stiffness in the metacarpophalangeal joint: circadian variation.

A finger arthrograph has been used to investigate circadian variation of stiffness in the metacarpophalangeal joints of normal subjects. A marked increase in the resistive torques of male and female joints was noted during the early hours of the morning (typically 2 to 3 times the torque found during the afternoon). The amount of energy dissipated by the joint and associated soft tissues also showed a circadian variation, with the highest levels of energy dissipation again occurring during the early hours of the morning (0200-0400).

Circadian Rhythm↗
PubMed1982

Measurement of stiffness in the metacarpophalangeal joint: the arthrograph.

A new type of finger arthrograph is described that evaluates the stiffness parameters of the metacarpophalangeal joint of the index finger at 10 degrees increments of flexion and extension. Stiffness is evaluated in terms of the energy loss per cycle (of amplitude 4 degrees), at every 10 degrees interval from 4 degrees to 94 degrees of flexion and by the mid-position torque and the mean slope of the least-squares fitted line through the graph of resistive torque against angular displacement. The instrument is simple to use, quick and comfortable for the patient, and gives reproducible results.

Equipment and Supplies↗
PubMed1982

Modes of lubrication in human hip joints.

Cadaveric hip joints were tested in a hip function simulator which subjected the femoral head to a cycle of loading and oscillation similar to that experienced during walking and measured the frictional torque transmitted to the acetabulum. Silicone fluids with viscosities from 10-2 Pa s (pascal second) to 30 Pa s were used as lubricants and the transition from mixed to full fluid film lubrication was observed around 5 x 10(-2) Pa s. Sodium carboxymethylcellulose solutions were also tested at the lower viscosities. Hyaluronidase digestion of samples of synovial fluid caused a significant increase in friction over the control samples. Trypsin digestion had no significant effect. No correlation between compliance of the cartilage and the frictional values was observed.

Elasticity↗
PubMed1981

Stiffness in the metacarpo-phalangeal joints of young adults.

A simple design of arthrograph is described and used to study the stiffness of the metacarpo-phalangeal joints of 55 subjects between the ages of 18 and 25. The apparatus and experimental technique produced results which were repeatable to within four percent. Results obtained when the tests were conducted at different angles of flexion showed that the direction of approach to the angle of flexion was important. For example, if the same angular position were approached first from a greater angle of flexion and then from a smaller angle of flexion, the resulting measured resistive torques were different. However, the two different values were repeatable and not dependent on the order of testing. Stress relaxation of the soft tissues surrounding the joint was observed while the variation in the equilibrium position (resting angle of flexion) was seen to be from 16 to 44 deg (mean 33.2). Stiffness was strongly correlated with subject mass and weakly correlated with wrist circumference. Women exhibited lower joint stiffness than mean but some of this difference may be due to their lower body mass.

Adolescent↗
PubMed1975

Some new evidence on human joint lubrication.

Theoretical consideration has been given to the use of pendulum machines which are used to examine the frictional properties of human joints by incorporating them as fulcra. As a result, a new type of pendulum machine has been built which incorporates the facility to apply sudden loads to the joint on starting the swinging motion, and also the ability to measure directly the frictional torque experienced by the joint. The results obtained from natural hip joints indicate the presence of squeeze film lubrication under conditions of sudden loading of a joint. In addition, a self-generated fluid film process was observed at low loads while at higher loads boundary lubrication appeared to be important. These results have been used to describe the lubrication regimens occurring in a normal activity such as walking. A single experiment carried out on a hip from a patient suffering from severe rheumatoid arthritis has also been reported and the frictional resistance was seen to be increased fifteenfold compared to a normal hip.

Arthritis, Rheumatoid↗
PubMed1975

Quantitative study of stiffness in the knee joint.

Data from a knee arthrograph, which imparts a passive sinusoidal motion to the joint and measures the resistive torque and displacement, have been shown to be reproducible. Tests carried out on joints (from 49 males, 21 females) showed that the energy loss per cycle of the joint increased with age for both sexes but the peak to peak torque (elastic stiffness) did not vary with age. Muscle bulk had a large influence on the stiffness (both dissipative and elastic) of the knee as did the size of the joint itself. Women's knee joints exhibited lower values of dissipative energy loss and peak to peak torque than men's for all ages and sizes of joints.

Adult↗