Faculty Bibliography

The change in spinal configuration of the cervical, thoracic, and lumbar regions in relation to an amount of weight lifted was determined using videophotogrammetry. Fifteen healthy male subjects, 20-38 years of age, with no previous history of back pain participated in the study. The subjects lifted a crate containing 0, 10, and 20 kg weights using the straight-legs, bent-over-back method of lifting. The results showed that cervical and thoracic spinal segment configurations were not significantly influenced by the amount of weight lifted and that the mobility of the lumbar spinal segment was significantly decreased with increasing load (p = .03)

Prompted by previous reports on muscle thixotropy, we have investigated changes in inherent and reflex stiffness of the finger flexor muscles of human subjects at rest, following transient conditioning manoeuvres involving contractions and/or length changes of the finger flexors. The stiffness measurements were combined with electromyographic recordings from forearm and hand muscles and with microneurographic recordings of afferent stretch responses in finger flexor nerve fascicles. Finger flexor stiffness was evaluated by measuring (a) the flexion angle of the metacarpo-phalangeal joints at which the system during rest balanced the force of gravity and (b) the speed and amplitude of angular finger extensions induced by recurrent extension torque pulses of constant strength delivered by a torque motor. In the latter case, extension drifts in the resting position of the fingers were prevented by a weak flexion bias torque holding the fingers in a pre-determined, semiflexed position against a stop-bar. Stiffness changes following passive large amplitude finger flexions and extensions were studied in subjects with nerve blocks or nerve lesions preventing neurally mediated contractions in the forearm and hand muscles. Inherent stiffness was enhanced following transient finger flexions and reduced following transient finger extensions. The after-effects gradually declined during observation periods of several minutes. Similar results were obtained in subjects with intact innervation who succeeded during the pre- and post-conditioning periods in keeping the arm and hand muscles relaxed (i.e. showed no electromyographic activity). In these subjects it was also found that the after-effects were similar for active and passive finger movements and that isometric voluntary finger flexor contractions loosened the system in a way similar to finger extensions. In some subjects electromyographic reflex discharges appeared in the finger flexors in response to the extension test pulses. When elicited by small ramp stretch stimuli of constant amplitude, the stretch reflex responses were found to vary in strength in parallel with the changes in inherent stiffness following the various conditioning manoeuvres. The strength of the multi-unit afferent stretch discharges in the muscle nerve, used as index of muscle spindle stretch sensitivity, varied in parallel with the changes in inherent stiffness. Post-manoeuvre changes in muscle spindle stretch sensitivity were seen also when the spindles were de-efferented by a nerve block proximal to the recording site. The results can be explained in terms of thixotropic behaviour of extra- and intrafusal muscle fibres.(ABSTRACT TRUNCATED AT 400 WORDS)

In a prospective study, 90 consecutive patients with total midstructural tears of the anterior cruciate ligament (ACL) were assigned at random to surgical (Group I) or conservative (Group II) treatment. Within 18.2 months of operation, 95% of the patients in Group I and 11% of those in Group II had a stable knee. The mean knee function score in Group I was 89 points, and 75% achieved more than 84 points (good or excellent). In Group II the mean score was 85; only 53% achieved more than 84 points (p less than .05). Group II patients showed greater mean quadriceps strength than those in Group I. The ability to perform a one-leg jump and to run a figure eight was similar in both groups. Early primary suture of the acutely torn ACL usually resulted in a stable knee, whereas conservatively treated patients showed knee instability. At the 18-month interval, however, the patients' functional performance seemed to be comparable in the two groups

Ectopically generated and antidromically conducted nerve impulses were recorded in 5 patients with tungsten microelectrodes inserted into skin nerve fascicles. All patients had mainly positive sensory symptoms and reported paresthesiae which could be provoked by different maneuvers which suggested increased mechanosensitivity of the primary sensory neurons at different anatomic levels. Ectopic multiunit nerve activity correlating in intensity and time course to the positive sensory symptoms was recorded: when Tinel's sign was elicited in a patient with entrapment of the ulnar nerve at the elbow, when paresthesiae were provoked by elevation of the arm in a patient with symptoms consistent with a thoracic outlet syndrome, when paresthesiae were evoked by straining during chin-chest maneuver in a patient with an S1 syndrome due to a herniated lumbar disc, when a painful Lasegue's sign occurred during the straight-leg raising test in a patient with an S1 syndrome due to root fibrosis, and when Lhermitte's sign was elicited by neck flexion in a patient with multiple sclerosis. The sites for the ectopic impulse generation in these cases are suggested to be peripheral nerve, brachial plexus, dorsal root or dorsal root ganglion and dorsal columns. The paresthesiae were non-painful except in the patient with Lasegue's sign and the ectopic impulses were probably recorded from large myelinated afferent fibers

To study spinal movements during work, an instrument that measured angles and angle changes in relation to a vertical plane was adapted to continuously measure forward flexion of the trunk. The instrument, which is battery-powered and worn on the back, registers the amount of flexion and its distribution over time during a work cycle by recording the time spent in each of five 18 degrees intervals between 0 degrees and 90 degrees. Also the number of times that the angle of flexion changed from one interval to another is recorded. A total of 43 subjects from three occupations--dentistry, nurses' aide work, and warehouse work--were each tested during a 60 minute work cycle. On the average, the dentists spent most of the time (52.2 minutes) in a semi-flexed position not exceeding 36 degrees and performed eight deep forward flexions (greater than 73 degrees). The nurses' aides spent one-half of the work cycle (34.4 minutes) in an upright position (0-18 degrees) and performed 70 deep forward flexions. The warehouse workers spent less than one-half of the work cycle in an upright position (27.5 minutes) and performed 153 deep forward flexions that nearly always were associated with lifting

The influence of a preventive educational back care programme on the movement patterns of the spine during work was assessed objectively and subjectively in six janitors. Trunk flexion was measured in the subjects using a flexion analyser before they attended a preventive educational back care programme and twice afterwards. The results show that the subjects increased the amount of time spent in an upright position by about a third after the educational programme and maintained this change two and a half to three months later. They also decreased the time spent in moderate and deep forward flexion (37-72 degrees ) by about half and also maintained this decrease at three months. These changes are consistent with a decrease of the mechanical load on the spine. The study emphasises that it is possible to alter movement patterns of the spine, and thereby decrease the load during janitorial work, by a suitably designed educational programme

The object of this study was to analyze the quadriceps muscle peak strength with the Cybex-II isokinetic dynamometer in patients with patellofemoral arthralgia with and without a patella brace. Twenty-four patients, 18 women and 6 men, were studied. All had patellofemoral arthralgia. The diagnosis was made on typical clinical findings, but was supplemented with arthroscopy in seven patients with pain also over the medial joint line. After a 2 week adaptation period with the brace, a Cybex-II test was done with and without the brace. The other leg was tested as control. Twenty-one patients (88%) improved their performance in the strength test with the brace (mean difference 13.7 +/- 9.1%). With the brace, 14 patients (58%) performed at 95% of their control leg or more compared to 6 (25%) without the brace. Patients under the age of 30 years had a better effect than patients over that age

Intra-abdominal pressures were measured simultaneously with a wireless radio pill and two wire-connected pressure transducers introduced orally and rectally respectively. Measurements were made on 8 men during common postures, simple activities and static and dynamic lifting. An acceptable correspondence was found in wave forms of the generated pressure curves in time and shape. The three systems showed, however, a less good agreement in recorded peak differences, i.e. highest and lowest pressure responses to each task. The radio pill is simple to use, but more difficult to calibrate and expensive, compared to the wire-connected methods, which however are less attractive for use in the work environment