Biomedical subjects

K M Refshauge

Publications and source records attributed to K M Refshauge.

17 recordsLinked to original sources

PubMed2006

Pectoral stretching program for women undergoing radiotherapy for breast cancer.

Surgery and radiotherapy commonly cause adverse musculoskeletal problems, particularly loss of strength and range of motion, in the upper quadrant of breast cancer patients. Few well-designed studies have investigated whether these impairments can be prevented. Stretching is an effective technique for increasing range of motion, hence the aim of this study was to investigate whether a stretching program reduced acute musculoskeletal impairments in patients undergoing radiotherapy for breast cancer. Sixty-four women were recruited prior to commencement of radiotherapy following breast cancer surgery. Participants were randomised to either a control or stretch group. Participants in both groups were reviewed by the physical therapist on a weekly basis for approximately 6 weeks, and were given general information about skin care and lymphedema. The control group received no advice about exercise. The stretch group received instruction on low-load, prolonged pectoral stretches, which were to be performed daily and were checked at weekly visits. Shoulder range of motion, strength, arm circumference, and quality of life measurements were taken prior to, and at completion of radiotherapy, and at 7 months after radiotherapy. There was no difference in any outcome between groups. Breast symptoms increased for both groups during radiotherapy, without loss of strength or range of movement. The incidence of lymphedema during the study was low for both groups and did not differ between groups. The pectoral stretching program did not influence the outcomes measured because the symptoms reported by patients were not a consequence of contracture.

Breast Neoplasms↗

PubMed2006

Design of a knee rotatory kinaesthetic device.

The anterior cruciate ligament (ACL) constrains rotatory motion at the knee and is commonly injured during rotational movements in athletic activity. This densely innervated ligament is assumed to play a role in knee proprioception, however, no study has measured proprioception in a manner relevant to either the kinematics of the ligament or the mechanism of injury, partly because of a lack of suitable equipment. The aims of this technical note are to document the development of a novel knee rotatory kinaesthetic device, and to present details of its construction, reproducibility, accuracy and application. The purpose-built device allows rotational movements at the knee to occur with minimal frictional resistance and provides accurate limits to the magnitude of these movements. This allows analysis of subjects' ability to discriminate between movements of differing magnitudes and thus allows calculation of subjects' sensitivity to small differences in magnitude of active knee rotation. Measurements taken with the device had a high level of agreement with those of a calibrated digital inclinometer (ICC=0.99; 95% CI 0.88 to 0.99) with a mean error of 0.24 degrees . The device also demonstrated excellent reproducibility (Pearson's r=1.0). A single case study is presented to detail the clinical application of the device. This novel device allows subjects to perform active knee rotational movements in a closed kinetic chain with discrete, self-paced movement, enabling calculation of movement discrimination. The device is compact and portable enabling testing to be undertaken in remote settings enhancing its clinical applicability.

Adult↗

PubMed2006

Do voluntary strength, proprioception, range of motion, or postural sway predict occurrence of lateral ankle sprain?

Prevention of ankle sprain, the most common sporting injury, is only possible once risk factors have been identified. Voluntary strength, proprioception, postural sway, and range of motion are possible risk factors. A systematic review was carried out to investigate these possibilities. Eligible studies were those with longitudinal design investigating ankle sprain in subjects aged > or = 15 years. The studies had to have measured range of motion, voluntary strength, proprioception, or postural sway before monitoring incidence of lateral ankle sprain. Dorsiflexion range strongly predicted risk of ankle sprain. Postural sway and possibly proprioception were also predictors. Therefore the preliminary evidence suggests that people with reduced ankle dorsiflexion range may be at increased risk of ankle sprain.

Ankle Injuries↗

PubMed2006

Low back pain investigations and prognosis: a review.

Low back pain is reviewed in terms of when investigations are useful and its clinical course. Despite the extensive evaluation of the accuracy of investigations such as radiography, magnetic resonance imaging, and myelography, there is a surprising dearth of research to inform their use in primary care. There is no clear evidence on which to base judgments for selection of appropriate tests to confirm or exclude low back pain pathology. It appears that investigations are rarely necessary for low back pain. Specific investigations should be ordered to identify a particular pathology but should not be ordered routinely for general screening. In the absence of pathology, low back pain and its associated disability improve rapidly in the first weeks after onset, but, in contradiction to all guidelines, both commonly persist and the best evidence suggests that recurrences are common.

Humans↗

PubMed2006

Does anterior cruciate ligament reconstruction restore normal knee kinematics?: A prospective MRI analysis over two years.

This prospective study used magnetic resonance imaging to record sagittal plane tibiofemoral kinematics before and after anterior cruciate ligament reconstruction using autologous hamstring graft. Twenty patients with anterior cruciate ligament injuries, performed a closed-chain leg-press while relaxed and against a 150 N load. The tibiofemoral contact patterns between 0 degrees to 90 degrees of knee flexion were recorded by magnetic resonance scans. All measurements were performed pre-operatively and repeated at 12 weeks and two years. Following reconstruction there was a mean passive anterior laxity of 2.1 mm (sd 2.3), as measured using a KT 1000 arthrometer, and the mean Cincinnati score was 90 (sd 11) of 100. Pre-operatively, the medial and lateral contact patterns of the injured knees were located posteriorly on the tibial plateau compared with the healthy contralateral knees (p=0.014), but were no longer different at 12 weeks (p=0.117) or two years postoperatively (p=0.909). However, both reconstructed and healthy contralateral knees showed altered kinematics over time. At two years, the contact pattern showed less posterior translation of the lateral femoral condyle during flexion (p<0.01).

Adult↗

PubMed2005

Cutaneous receptors contribute to kinesthesia at the index finger, elbow, and knee.

The neural mechanisms underlying the sense of joint position and movement remain controversial. While cutaneous receptors are known to contribute to kinesthesia for the fingers, the present experiments test the hypothesis that they contribute at other major joints. Illusory movements were evoked at the interphalangeal (IP) joints of the index finger, the elbow, and the knee by stimulation of populations of cutaneous and muscle spindle receptors, both separately and together. Subjects matched perceived movements with voluntary movements of homologous joints on the contralateral side. Cutaneous receptors were activated by stretch of the skin (using 2 intensities of stretch) and vibration activated muscle spindle receptors. Stimuli were designed to activate receptors that discharge during joint flexion. For the index finger, vibration was applied over the extensor tendons on the dorsum of the hand, to evoke illusory metacarpophalangeal (MCP) joint flexion, and skin stretch was delivered around the IP joints. The strong skin stretch evoked the illusion of flexion of the proximal IP joint in 6/8 subjects (12 +/- 5 degrees, mean +/- SE). For the group, strong skin stretch delivered during vibration increased the perceived flexion of the proximal IP joint by eight times with a concomitant decrease in perceived flexion of the MCP joint compared with vibration alone (P < 0.05). For the elbow, vibration was applied over the distal tendon of triceps brachii and skin stretch over the dorsal forearm. When delivered alone, strong skin stretch evoked illusory elbow flexion in 5/10 subjects (9 +/- 4 degrees). Simultaneous strong skin stretch and vibration increased the illusory elbow flexion for the group by 1.5 times compared with vibration (P < 0.05). For the knee, vibration was applied over the patellar tendon and skin stretch over the thigh. Skin stretch alone evoked illusory knee flexion in 3/10 subjects (8 +/- 4 degrees) and when delivered during vibration, perceived knee flexion increased for the group by 1.4 times compared with vibration (P < 0.05). Hence inputs from cutaneous receptors, muscle receptors, and combined inputs from both receptors likely subserve kinesthesia at joints throughout the body.

Adult↗

PubMed2003

The detection of human finger movement is not facilitated by input from receptors in adjacent digits.

These experiments were designed to determine whether cutaneous input from a digit provides a general facilitation of the detection of movements applied to an adjacent digit. The ability to detect passive movements at the proximal interphalangeal joint of the right index finger was measured when cutaneous (and joint) input was removed (using local anaesthesia) from the tip of one or both digits adjacent to the test finger (16 subjects). The same parameter was also measured when input was artificially increased by stimulation of the adjacent digits at three intensities: below, above and at perceptual threshold (PT; 15 subjects). Detection of flexion or extension movements was not altered by anaesthesia of one or both adjacent digits. Since it was possible that too few tonically active afferents in the hand had been blocked to reveal an effect, the median nerve was blocked, with movements applied to the little finger, causing no measurable impairment in acuity (three subjects). Simultaneous electrical stimulation of the tips of the adjacent digits at intensities above PT impaired movement detection, but had no effect when delivered at or below PT. To test whether the effect of detectable electrical stimuli was due to a specific interaction between the artificial input and the input evoked by moving the digit, or due to mental distraction, stimuli were delivered above PT to either the left or right little finger, or the test index finger during movement of the index finger. Electrical stimulation of the index finger significantly reduced detection by approximately 50%, but stimulation of the remote little fingers did not. Electrical stimulation is a non-natural stimulus, so a "natural" stimulus was applied by continuously stroking the tips of the adjacent digits with a brush (10 subjects). The natural stimulus also significantly reduced movement detection by approximately 50%. Together, these findings suggest that tonic inputs from digital nerve afferents adjacent to, or more remote from the passively moved finger do not facilitate movement detection. However, the reduced detection during stimulation of the adjacent digits shows that there is nevertheless some interaction between the various proprioceptive inputs from the digits.

Adult↗

PubMed2001

Causes of complications from cervical spine manipulation.

Cervical manipulation occasionally causes serious vertebrobasilar complications. The usual cause is vertebral artery dissection, however in some cases there has been no obvious arterial injury. The present paper reviews the mechanisms by which complications occur, particularly when the applied force is trivial or there is no injury to the vertebral arteries, and the factors that increase risk of complications. In addition, implications are drawn for use of the recently revised Australian Physiotherapy Association (APA) guidelines. In the absence of vertebral artery rupture, complications are proposed to arise from vasospasm, haemostasis, endothelial injury or turbulent flow. These mechanisms have a sound scientific basis but have yet to be demonstrated as specifically causing vertebrobasilar complications. The most important risk factors for vertebrobasilar complications appear to be prior trauma to the vertebral arteries and symptoms of vertebrobasilar ischaemia from previous manipulation. There is weak evidence that hypoplasia of the vertebral arteries also increases the risk of complications. Neither general vascular factors nor pre-existing degenerative conditions of the cervical spine increase risk of vertebrobasilar complications. The procedures described in the APA guidelines test adequacy of total cerebral perfusion during cervical movements rather than patency of the vertebral arteries or their susceptibility to injury. The guidelines may therefore indicate potential for surviving a complication from manipulation. They may also identify patients at risk of complications from minor trauma. It is recommended that the procedures described in the APA guidelines be applied prior to every manipulation, and that manipulation be avoided in the presence of any signs of vertebrobasilar insufficiency.

Humans↗

PubMed2000

Sensory integration in the perception of movements at the human metacarpophalangeal joint.

These experiments were designed to investigate illusions of movements of the fingers produced by combined feedback from muscle spindle receptors and receptors located in different regions of the skin of the hand. Vibration (100 Hz) applied in cyclic bursts (4 s 'on', 4 s 'off') over the tendons of the finger extensors of the right wrist produced illusions of flexion-extension of the fingers. Cutaneous receptors were activated by local skin stretch and electrical stimulation. Illusory movements at the metacarpophalangeal (MCP) joints were measured from voluntary matching movements made with the left hand. Localised stretch of the dorsal skin over specific MCP joints altered vibration-induced illusions in 8/10 subjects. For the group, this combined stimulation produced movement illusions at MCP joints under, adjacent to, and two joints away from the stretched region of skin that were 176 +/- 33, 122 +/- 9 and 67 +/- 11 % of the size of those from vibration alone, respectively. Innocuous electrical stimulation over the same skin regions, but not at the digit tips, also 'focused' the sensation of movement to the stimulated digit. Stretch of the dorsal skin and compression of the ventral skin around one MCP joint altered the vibration-induced illusions in all subjects. The illusions became more focused, being 295 +/- 57, 116 +/- 18 and 65 +/- 7 % of the corresponding vibration-induced illusions at MCP joints that were under, adjacent to, and two joints away from the stimulated regions of skin, respectively. These results show that feedback from cutaneous and muscle spindle receptors is continuously integrated for the perception of finger movements. The contribution from the skin was not simply a general facilitation of sensations produced by muscle receptors but, when the appropriate regions of skin were stimulated, movement illusions were focused to the joint under the stimulated skin. One role for cutaneous feedback from the hand may be to help identify which finger joint is moving.

Electric Stimulation↗

PubMed2000

Lumbar spine traction: evaluation of effects and recommended application for treatment.

Despite the widespread use of traction, little is known of the mode of effect, and application remains largely anecdotal. The efficacy of traction is also unclear because of generally poor design of the clinical trials to date, and because subgroups of patients most likely to benefit have not been specifically studied. These observations prompted this review, the purposes of which are to evaluate the mechanisms by which traction may provide benefit and to provide rational guidelines for the clinical application of traction. Traction has been shown to separate the vertebrae and it appears that large forces are not required. Vertebral separation could provide relief from radicular symptoms by removing direct pressure or contact forces from sensitised neural tissue. Other mechanisms proposed to explain the effects of traction (e.g. reduction of disc protrusion or altered intradiscal pressure) have been shown not to occur. We conclude that traction is most likely to benefit patients with acute (less than 6 weeks' duration) radicular pain with concomitant neurological deficit. The apparent lack of a dose-response relationship suggests that low doses are probably sufficient to achieve benefit.

Animals↗

PubMed2000

The effect of recurrent ankle inversion sprain and taping on proprioception at the ankle.

PURPOSE: A common explanation for the tendency for ankle inversion sprains to recur is that proprioception is impaired by the initial sprain. It is further hypothesized that the application of tape prevents further sprains by enhancing proprioceptive acuity. The purpose of this study was to determine whether proprioception was impaired in people with recurrent ankle inversion sprain, and whether taping the ankle provided enhanced proprioceptive ability. METHODS: We compared the ability to perceive passive plantarflexion and dorsiflexion movements imposed at the relaxed ankle in 25 subjects with recurrent ankle inversion sprain, with a group of 18 healthy control subjects, matched for age, height, weight, and activity level. Subjects were tested with the ankle both taped and untaped. Detection thresholds were determined at three velocities, 0.1 degrees x s(-1), 0.5 degrees x s(-1), and 2.5 degrees x s(-1). Velocity of the imposed movements and testing of the taped and untaped conditions were randomized. RESULTS: There was no significant difference in the ability to perceive ankle movements between subjects with sprains and healthy controls at any velocity of movement tested. In addition, there was no significant difference in movement perception between the taped and untaped conditions for either subject group at any velocity. CONCLUSION: The ability to detect passive plantarflexion and dorsiflexion movements is not impaired in subjects with recurrent ankle inversion sprain. Furthermore, the protective effect of taping was shown not to arise from enhanced proprioception in the dorsiflexion-plantarflexion plane.

Adolescent↗

PubMed1998

Movement detection at the human big toe.

1. To be detected, movements of the interphalangeal joint of the big toe must be greater than at other joints. This poor acuity may arise because the anatomy of the foot and ankle results in poor coupling between the toe and the muscles that operate it. To vary this coupling, the effect of ankle position on proprioceptive acuity at the toe was measured. 2. We measured proprioceptive acuity at the toe with the ankle in different positions and found that ankle plantarflexion did improve acuity. This implies that, with the ankle at mid-range or dorsiflexed, toe movement is inadequately transferred to muscle fascicles. 3. To determine actual changes in fascicle length of the toe extensor, movements of extensor hallucis longus near the toe and at the muscle-tendon junction were measured during surgical exposure in one subject. Ankle position greatly affected movement transfer from toe to muscle-tendon junction: no tendon movement was transferred with the ankle dorsiflexed, but all movement was transferred with the ankle plantarflexed. 4. When the relationship between joint rotation and muscle fascicle length measured in vivo was used to express the smallest detectable movements of the toe as proportional changes in muscle fascicle length, these detectable changes were similar to those at all other limb joints. This suggests that change in muscle fascicle length is of major interest to the nervous system.

Adult↗

PubMed1998

Movement detection at the distal joint of the human thumb and fingers.

To determine whether proprioceptive acuity is the same at all digits, particularly when postured as in a 'grasp', we imposed 10 degrees movements at the distal joint of the thumb, index and ring finger, at three velocities; 1.25 degrees/s, 2.5 degrees/s and 5 degrees/s. The test joint was initially flexed by 25 degrees and the joints proximal to the test joint were maintained in a standard posture for each study. When in a grasp posture that disengaged the extensor muscles at the distal joint of the finger, movement detection at the thumb was superior to that at the fingers for all velocities. However, when the fingers were positioned so that all proprioceptive inputs were able to contribute (i.e. cutaneous, joint and both flexor and extensor muscle afferents), proprioceptive acuity was similar for the three digits. Loss of local cutaneous (and joint) inputs by digital anaesthesia significantly impaired performance at all digits, suggesting a critical role for cutaneous input in normal proprioceptive sensibility at all distal joints of the digits. Anaesthesia of the extensor muscle afferents innervating the thumb did not affect its proprioceptive acuity. Thus, for the thumb, the extensor muscle afferents do not provide critical information. The greater change in muscle fascicle length for the thumb's long flexor muscle (3% per 10 degrees) compared with that in the finger flexor muscles (e.g. 0.1% per 10 degrees) could contribute to the thumb's performance. There appears to be less redundancy of muscle and non-muscle signals for the fingers than for the thumb, because a reduction in either cutaneous or muscle input significantly impaired acuity at the fingers. Overall, when the hand is in a grasping posture, irrespective of the contribution of local cutaneous inputs, the long flexor acting on the thumb may contribute more to its proprioceptive acuity than the long finger flexors contribute to acuity at the fingers.

Adolescent↗

PubMed1995

Detection of movements imposed on human hip, knee, ankle and toe joints.

1. The angular displacements necessary for 70% correct detection were determined in normal subjects at the hip, knee and ankle joints, and the interphalangeal joint of the big toe. Angular velocities between 0.1 and 50 deg s-1 were tested. The hip and knee joints were tested in slight flexion and the ankle and toe joints were tested in the mid-range of the normal excursion. The joints were carefully supported for testing and the muscles acting at the joints were relaxed. 2. When detection thresholds and velocities were assessed in terms of angular displacements and angular velocities, proprioceptive performances at the hip, knee and ankle joints were superior to that at the toe joint. 3. When detection levels and displacement velocities were expressed in terms of linear displacements and velocities at the tip of the extended toe for all four joints, instead of in angular terms, the ankle gave the best performance and the hip and knee the worst. 4. The detection level and velocity data were expressed also in terms of proportional changes in the fascicle lengths of muscles operating these joints. Analysis in these terms showed that performance was similar at the hip, knee and ankle joints, but that performance for the toe was much poorer than for the other joints. 5. These results for the hip, knee and ankle are similar to those previously measured for the elbow and distal interphlangeal joint of the finger, and are consistent with the theory that muscle fascicle length is the variable of significance to the central nervous system. However, the proprioceptive performance at the big toe is notably poorer than all other joints studied and analysed in terms of this variable.

Adult↗

PubMed1995

Perception of movement at the human ankle: effects of leg position.

1. Recent studies show that subjects perceive smaller ankle movements when they are upright in the standing position than when they are seated. To examine this improvement, the ability to perceive ankle movements was tested in five positions of body, knee and ankle. Subjects reported the direction of slow ramp movements of the ankles. 2. The threshold for perceiving ankle movements was unchanged when only one ankle was moved rather than both together. When seated with the knees bent and ankles slightly plantarflexed, subjects perceived movements of 0.65 deg at 0.05 deg s-1. However, when upright or when seated with their knees and ankles in the standing position, subjects perceived movements that were one-third of this size. 3. These findings show that the knee and ankle positions, rather than being upright, explain the better performance in the standing position. During standing, knee extension and ankle dorsiflexion stretch the calf muscles. Thus, enhanced input from intramuscular stretch receptors appears responsible for the better performance.

Adult↗

PubMed1994

The relationship between surface contour and vertebral body measures of upper spine curvature.

STUDY DESIGN: In this study, parameters of sagittal cervical posture obtained from surface markers and from vertebral body locations were compared. OBJECTIVES: Several postural parameters were examined to establish the degree to which surface measures of cervical alignment reflect the underlying vertebral body alignment. SUMMARY OF BACKGROUND DATA: Previous studies of the relation between surface and vertebral alignment in the thoracic and lumbar regions have shown conflicting results. Some data suggest a connection between surface cervical posture and head and neck pain, but the relation between surface and vertebral posture in the cervical region has not been reported. METHODS: Lateral view radiographs of 24 healthy volunteers were used to give the surface alignment of skin markers and the locations of the geometric centers of vertebral bodies. Three angles describing sagittal alignment were investigated: 1) forward inclination of C2 relative to C7 (cervical inclination); 2) cervicothoracic kyphosis; and 3) cervical lordosis. RESULTS: A strong relationship between surface and vertebral data was not established. Two factors were identified as contributing to the observed differences: length of spinous processes and depth of soft tissue overlying the spinous processes at each spinal level. CONCLUSIONS: The assumption that the surface curve is the same as the vertebral curve is not supported by these results, suggesting caution is needed in inferring vertebral alignment from observed surface contours.

Adult↗

PubMed1994

Rotation: a valid premanipulative dizziness test? Does it predict safe manipulation?

OBJECTIVE: The purpose of this study was to investigate the validity of cervical spine rotation as a test of patency of the vertebral arteries (VAs) and the internal carotid arteries (ICAs). DESIGN: A descriptive study was undertaken. SETTING: Testing was carried out in a private clinical vascular unit attached to a large Sydney public hospital. PARTICIPANTS: Twenty healthy volunteers, both male and female, who were free of risk factors commonly associated with vascular disease, participated in the study. INTERVENTIONS AND MAIN OUTCOME MEASURES: An AutoSector 5 Duplex Doppler ultrasound instrument was used to record mean and peak frequency of blood flow (a measure of blood velocity) in the right and left VAs and ICAs in the cervical spine positions of neutral, 45 degrees contralateral rotation and full range contralateral rotation. To determine general hemodynamic stability, blood pressure and heart rate were recorded pre- and posttest, as well as in all tested positions. RESULTS: There was a significant trend for blood velocity to increase in 45 degrees contralateral rotation and to decrease in full rotation (p < .01). This trend was not consistent across vessels. Blood velocity decreased with rotation from neutral head position in the right VA, and continued to increase throughout rotation in the right ICA. CONCLUSION: It appears that sustained rotation influences blood velocity in the extracranial vessels. This may have relevance in patients with abnormal blood flow who are candidates for cervical manipulation.

Adult↗