Geoffrey R. Strauss

Knee Bracing: Effects on Proprioception

OBJECTIVE To examine the effects of a knee sleeve type brace on the proprioceptive ability of subjects with normal knees during a dynamic tracking task. DESIGN A 2 X 2 Latin square cross over design; in each Latin square, subjects were matched for age and gender. SETTING An institution focused on clinical education. PARTICIPANTS Twenty subjects with no musculoskeletal or neurological conditions. INTERVENTIONS Each subject performed a tracking task on a Kin-Com dynamometer. Angle and force data from the Kin-Com and angle data from an electrogoniometer were sampled at 100Hz using a data acquisition program on a PC computer. The subjects were blindfolded and the limb attached to the Kin-Com was moved passively by the dynamometer. Subjects were instructed to follow the movement as closely as possible with the other limb (the tracking limb). Subject performed two trials, one without knee bracing and another that involved the application of a brace to the tracking limb. OUTCOME MEASURE The magnitude of the error in tracking was established by taking the difference of the active and passively moving limbs and calculating the root mean square (RMS) of the difference. RESULTS The findings showed that there was an improvement of 11% in tracking when subjects wore the knee brace (p < .05). CONCLUSION Alterations in proprioception as a result of bracing may be partly responsible for the improvement in knee injury statistics reported in some studies.

Patient handling with and without slings: an analysis of the risk of injury to the lumbar spine.

Health professionals handling patients are known to be at risk of sustaining work related low back injuries. It is not known whether the use of lifting slings reduces the risk of injury to the lumbar spine for patient handlers. This study used kinematic variables and subjective ratings of body part stress and lifter preference as measures of relative risk for three two-person techniques for carrying a patient from one chair to another chair. The techniques used no slings, one and two slings respectively. Twenty-two nurses performed five trials each of the three techniques. Kinematic measures of angular displacement, velocity and acceleration were obtained using the lumbar motion monitor and visual analogue scales were used to obtain measures of body part stress for seven body parts. Angular displacement, velocity and acceleration were significantly greater (p < 0.05) in the frontal, sagittal and transverse planes for the no sling technique compared to techniques using slings. Comparatively small yet significant differences between techniques using slings were recorded for sagittal flexion and rotation. There was no significant difference between one and two sling techniques for other dependent variables. Mean total body stress rating was higher for the no sling technique and all subjects indicated that their first preference was for slings. Although all three measures of risk rated the no sling technique as carrying a higher level of risk than the techniques using slings. No single measure adequately captured all aspects of relative risk. The elimination of manual patient handling is thought to be the best option for the reduction of work related back injuries in patient handlers. Where resources or technology are not yet adequate to provide practical alternatives and where the use of manual technique for a seat to seat task is unavoidable, the use of patient handling slings will reduce the risk.

Functional measurement of knee joint position sense after anterior cruciate ligament reconstruction

OBJECTIVE To examine for differences in joint position sense (JPS) between knees with reconstructed anterior cruciate ligaments (ACLs) and uninjured knees by using a functional weight-bearing measurement method. DESIGN Two-way repeated-measures in a convenience sample. SETTING An Australian university rehabilitation laboratory. PARTICIPANTS Nine subjects presenting at 12 to 16 months after unilateral ACL reconstruction using the semitendinosus/gracilis graft who were recruited from 2 orthopedic surgeons. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES JPS of the reconstructed and uninjured knees was examined by using the Peak Motus motion measurement system to record target joint angles and to calculate reproduced angles after limb movement into flexion and extension, performed in a weight-bearing position. RESULTS There were no significant differences in JPS between reconstructed and uninjured knees (P=.68) or between the flexion and extension tasks (P=.47). CONCLUSION There was no deficit in knee JPS 12 to 16 months after ACL reconstruction, as measured by a functional weight-bearing method. Further studies should examine the clinical utility of the method as a way to evaluate functional aspects of knee joint proprioception.

Kinematic changes in jaw and lip control of children with cerebral palsy following participation in a motor-speech (PROMPT) intervention

Abstract This study evaluates kinematic movements of the jaw and lips in six children (3–11 years) with moderate-to-severe speech impairment associated with cerebral palsy before, during, and after participation in a motor-speech (PROMPT) intervention program. An ABCA single subject research design was implemented. Subsequent to the baseline phase (A), phase B targeted each participants first intervention priority on the PROMPT motor-speech hierarchy. Phase C then targeted one level higher. A reference group of 12 typically-developing peers, age- and sex-matched to each participant with CP, was recruited for comparison in the interpretation of the kinematic data. Jaw and lip measurements of distance, velocity, and duration, during the production of 11 untrained stimulus words, were obtained at the end of each study phase using 3D motion analysis (Vicon Motus 9.1). All participants showed significant changes in specific movement characteristics of the jaw and lips. Kinematic changes were associated with significant positive changes to speech intelligibility in five of the six participants. This study makes a contribution to providing evidence that supports the use of a treatment approach aligned with dynamic systems theory to improve the motor-speech movement patterns and speech intelligibility in children with cerebral palsy.

Extensor strength in the anterior cruciate reconstructed knee

Truncated range average torque (TRAT), peak torque (PT) and angle of peak torque (APT) in the knee extensor musculature of subjects with patellar tendon autograft anterior cruciate ligament reconstructions were compared with non-operated limbs two to four years following surgery. Twenty subjects were assessed using a Kin-Com 500H isokinetic dynamometer at three velocities for both concentric and eccentric muscle actions. Results of TRAT for the knee extensors showed average concentric and eccentric deficits of 8.48 per cent and 6.73 per cent, respectively. Deficits in PT were 8.26 per cent concentrically and 7.96 per cent eccentrically. There was no difference in the APT for each action or velocity. Despite an accelerated rehabilitation program, significant residual deficits were evident. Continued strengthening of the knee extensor muscles is recommended.

M-mode ultrasound used to detect the onset of deep muscle activity

M-mode ultrasound imaging (US) reflects motion of connective tissue within muscles. As muscle contraction is accompanied by motion of muscle tissue, M-mode US may be used to measure non-invasively the onset of deep muscle activity. Isometric hip abduction was measured on nine healthy subjects in the deep region of the gluteus medius muscle and in gluteus minimus by fine-wire electromyography (EMG) and M-mode US. Following signal transformation with the Teager-Kaiser Energy Operator, EMG and M-mode US onsets of muscle activity were computer-processed. Correlation between log-transformed EMG and M-mode high-energy onsets was higher in gluteus medius (r 0.93) than in gluteus minimus (r 0.86). M-mode high-energy onsets followed EMG onset by median 33 (IQR 53) ms in gluteus medius, and by 17 (IQR 63) ms in gluteus minimus. 4% of gluteus medius and 23% of gluteus minimus M-mode onsets were detected before EMG onset. Using a higher onset threshold reduced the rate of onsets detected before EMG but also prediction accuracy. In voluntary activation, M-mode US high-energy onsets were closely related to EMG-measured onsets, but the time interval between both measures varied. The relationship of electrical and mechanical activation onsets appears to be influenced by modifying factors which may differ between muscles.

M-Mode Ultrasound Reveals Earlier Gluteus Minimus Activity in Individuals With Chronic Hip Pain During a Step-down Task

STUDY DESIGN Controlled laboratory study. BACKGROUND The hip abductor muscles are important hip joint stabilizers. Hip joint pain may alter muscle recruitment. Motion-mode (M-mode) ultrasound enables noninvasive measurements of the onset of deep and superficial muscle motion, which is associated with activation onset. OBJECTIVES To compare (1) the onset of superficial and deep gluteus medius and gluteus minimus muscle motion relative to the instant of peak ground reaction force and (2) the level of swing-phase muscle motion during step-down between subjects with chronic hip pain and controls using M-mode ultrasound. METHODS Thirty-five subjects with anterior, nontraumatic hip pain for more than 6 months (mean ± SD age, 54 ± 9 years) and 35 controls (age, 57 ± 7 years) were scanned on the lateral hip of the leading leg during frontal step-down onto a force platform using M-mode ultrasound. Computerized motion detection with the Teager-Kaiser energy operator was applied on the gluteus minimus and the deep and superficial gluteus medius to determine the time lag between muscle motion onset and instant of peak ground reaction force and the level of gluteus minimus motion during the swing phase. Time lags and motion levels were averaged per subject, and t tests were used to determine between-group differences. RESULTS In participants with hip pain, gluteus minimus motion onset was 103 milliseconds earlier (P = .002) and superficial gluteus medius motion was 70 milliseconds earlier (P = .047) than those in healthy control participants. The level of gluteus minimus swing-phase motion was higher with pain (P = .006). CONCLUSION Increased gluteus minimus motion during the swing phase and earlier gluteus minimus and superficial gluteus medius motion in individuals with hip pain suggest an overall increase of muscle activity, possibly a protective behavior.

Separate assessment of gluteus medius and minimus: B-mode or M-mode ultrasound?

Abstract The hip abductors gluteus medius (Gmed) and minimus (Gmin) differ slightly in function and how they are affected by hip joint pathology. A separate assessment of Gmed and Gmin is feasible by ultrasound (US) imaging. B-mode and M-mode US can be used to measure muscle thickness. Two B- and two M-mode scans of Gmed and Gmin thickness were taken in relaxation on 16 asymptomatic volunteers, repeated within 4 days on 11 subjects. Three types of intra-rater reliability of muscle thickness measurements were examined: (1) within-session reliability comparing two scans from the same session, (2) between-days reliability comparing thickness from two scanning occasion within 4 days and (3) reliability of taking thickness measurements by re-measuring the same US scans after 1 week. Thickness measurements on B- and M-mode images provided ICC3,1 >0.96 for within-session reliability. ICC3,k >0.89 for between-days reliability and ICC3,1 >0.85 for re-reading the same scans were estimated. Minimal detectable changes >1.0 mm within-session, >2.4 mm between-days and >1.7 mm for re-reading scans indicated that small thickness changes are not detectable. The investigation suggests a slight advantage for fascia recognition in B-mode and the advantage of visual control of muscle relaxation in M-mode.