Luc J. Hébert

Gait study of patients with patellofemoral pain syndrome

Patellofemoral pain syndrome is a frequent knee impairment in young adults. This study investigated the kinematic and kinetic gait patterns of individuals suffering from patellofemoral pain syndrome (PFPS). It was hypothesized that PFPS subjects modify their gait pattern in order to reduce loading on the painful patellofemoral joint. To verify this, the gait pattern of five subjects with right chronic PFPS was compared with that of five healthy subjects. Spatiotemporal, kinematic and kinetic data were collected from five gait cycles. The joint moments at the hip, knee and ankle joints were calculated using an inverse dynamic approach and the values were normalized to body weight (N·m/kg). Individual joint moments were expressed as a percentage of the support moment in order to quantify possible compensatory strategies. The kinematic analysis revealed a significant reduction of the knee flexion angle (ANOVAs, P 0.05) as far as the individual joint moments and their contribution to the support moment were concerned. However, modifications were observed in the knee and hip moments between 10% and 20% of the gait cycle. These modifications may suggest that PFPS subjects alter their gait pattern in order to reduce loading of the patellofemoral joint to avoid pain.

Effect of motor control and strengthening exercises on shoulder function in persons with impingement syndrome: a single-subject study design.

The aim of the study was to evaluate the effect of an intervention including shoulder control and strengthening exercises on function in persons with shoulder impingement. Eight subjects with shoulder impingement were evaluated weekly during the nine weeks of this single-subject design study. The study was divided into three phases (A(1)-B-A(2)) and involved repeated measures of shoulder pain and function (Shoulder Pain And Disability Index (SPADI) questionnaire), painful arc of motion, peak torque and 3-dimensional scapular attitudes. During the intervention phase, each subject participated in 12 exercise sessions supervised by a physiotherapist. Measures taken during the intervention and post-intervention phases were compared to pre-intervention values. All subjects showed significant improvement in the SPADI at the end of the study. A disappearance of a painful arc of motion in flexion and abduction (n=6), an increase in isometric peak torque in lateral rotation (n=3) and abduction (n=2), and changes in the scapular kinematics, mainly in the sagittal plane, were also observed. The present results provide preliminary evidence to support the use of shoulder control exercises to reduce pain and improve function of persons with shoulder impingement.

Isometric muscle strength in youth assessed by hand-held dynamometry: a feasibility, reliability, and validity study.

Purpose: To determine, with respect to measurement of maximal isometric torque (MIT) using a specific hand-held dynamometer (HHD) protocol, (1) protocol feasibility over a wide age range, (2) intra- and interrater reliability, (3) standard error of measurement, and (4) concurrent validity. Methods: The MIT of selected upper and lower limb muscle groups was assessed (n = 74; age = 4-17.5 years) using a standardized, HHD protocol. Testing was repeated in 20 adolescents (n = 10 for each muscle group), who were also assessed with a Cybex dynamometer. Results: The protocol was feasible for all participants. Mean intra- and interrater reliability [intraclass correlation coefficient (ICC)] varied from 0.75 to 0.98, except for ankle dorsiflexor interrater reliability (mean ICC = 0.67). The standard error of measurement varied from 0.5 to 4.9 Nm and was highest for hip extensors. Mean concurrent validity (ICC) varied from 0.78 to 0.93, except for ankle plantar flexors (mean ICC = 0.48). Conclusions: Our HHD protocol was feasible over a wide age range and most MIT values were valid and reliable.

A method of measuring three-dimensional scapular attitudes using the Optotrak probing system

OBJECTIVE To develop a method to obtain accurate three-dimensional scapular attitudes and to assess their concurrent validity and reliability. STUDY DESIGN In this methodological study, the three-dimensional scapular attitudes were calculated in degrees, using a rotation matrix (cyclic Cardanic sequence), from spatial coordinates obtained with the probing of three non colinear landmarks first on an anatomical model and second on a healthy subject. BACKGROUND Although abnormal movement of the scapula is related to shoulder impingement syndrome, it is not clearly understood whether or not scapular motion impairment is a predisposing factor. Characterization of three-dimensional scapular attitudes in planes and at joint angles for which sub-acromial impingement is more likely to occur is not known. METHODS The Optotrak probing system was used. An anatomical model of the scapula was built and allowed us to impose scapular attitudes of known direction and magnitude. A local coordinate reference system was defined with three non colinear anatomical landmarks to assess accuracy and concurrent validity of the probing method with fixed markers. Axial rotation angles were calculated from a rotation matrix using a cyclic Cardanic sequence of rotations. The same three non colinear body landmarks were digitized on one healthy subject and the three dimensional scapular attitudes obtained were compared between sessions in order to assess the reliability. RESULTS AND CONCLUSIONS The measure of three dimensional scapular attitudes calculated from data using the Optotrak probing system was accurate with means of the differences between imposed and calculated rotation angles ranging from 1.5 degrees to 4.2 degrees. Greatest variations were observed around the third axis of the Cardanic sequence associated with posterior-anterior transverse rotations. The mean difference between the Optotrak probing system method and fixed markers was 1.73 degrees showing a good concurrent validity. Differences between the two methods were generally very low for one and two direction displacements and the largest discrepancies were observed for imposed displacements combining movement about the three axes. The between sessions variation of three dimensional scapular attitudes was less than 10% for most of the arm positions adopted by a healthy subject suggesting a good reliability. The Optotrak probing system used with a standardized protocol lead to accurate, valid and reliable measures of scapular attitudes. RELEVANCE Although abnormal range of motion of the scapula is often related to shoulder pathologies, reliable outcome measures to quantify three-dimensional scapular motion on subjects are not available. It is important to establish a standardized protocol to characterize three-dimensional scapular motion on subjects using a method for which the accuracy and validity are known. The method used in the present study has provided such a protocol and will now allow to verify to what extent, scapular motion impairment is linked to the development of specific shoulder pathologies.

The ability of the Biodex Stability System to distinguish level of function in subjects with a second-degree ankle sprain:

Objective: To assess the capacity of the Biodex Stability System using a one-leg stance protocol to differentiate between injured and non-injured limbs and between level of disabilities. Design: Cross-sectional study. Setting: Military and civilian clinic. Subjects: Thirty-four individuals with a second-degree lateral ankle sprain and 36 healthy subjects. Methods and measures: Subjects were tested on the Stability System 30 days after injury using a one-leg stance protocol in the dynamic limit-of-stability mode. All subjects also filled out a disability questionnaire (Lower Extremity Functional Scale). The groups were compared based on the overall dynamic limit-of-stability score and its relationship with the score on the disability questionnaire was also examined. Results: The overall dynamic limit-of-stability scores (subjects with a lateral ankle sprain: 13.0% (5.5)-26.0% (9.2); healthy subjects: 16.9% (7.9)-27.9% (9.6)) clustered in the lower end of the theoretical range of 0–100%. Statistically significant differences in the overall dynamic limit-of-stability scores were found between the injured and non-injured limbs but group differences were small and clinically not relevant. No significant relationships were found between the overall dynamic limit-of-stability scores and the Lower Extremity Functional Scale scores (58.2 (11.8)) of the subjects with a lateral ankle sprain. Conclusions: The one-leg stance protocol carried out in the dynamic limit-of-stability mode is very challenging and offers a very limited capacity to differentiate between injured and non-injured limbs. The main outcome of the Stability System does not appear to be a good indicator of the functional capacity of people with a lateral ankle sprain.

Quantitative assessment of skeletal muscle degeneration in patients with myotonic dystrophy type 1 using MRI.

To identify MRI biomarkers that could be used to follow disease progression and therapeutic efficacy in one individual muscle in patients with myotonic dystrophy type 1 (DM1).

The use of muscle strength assessed with handheld dynamometers as a non-invasive biological marker in myotonic dystrophy type 1 patients: a multicenter study

BackgroundMyotonic dystrophy type 1 (DM1) is a multisystem disorder that demonstrates variable symptoms and rates of progression. Muscle weakness is considered one of the main problems with a clinical picture that is characterized by distal weakness of the limbs progressing to proximal weakness. The main objective of this study was to characterize the maximal strength of ankle eversion and dorsiflexion in DM1 patients. Manual and handheld dynamometer (HHD) muscle testing were also compared.MethodsThe maximal strength of 22 patients from Quebec (mean age = 41,1 ± 13,8) and 24 from Lyon (mean age = 41,6 ± 10,2) were compared to 16 matched controls.ResultsWith the use of HHD, an excellent reproducibility of the torque measurements was obtained for both centers in eversion (R2 = 0,94/Quebec; 0,89/Lyon) and dorsiflexion (R2 = 0,96/Quebec; 0,90/Lyon). The differences between 3 groups of DM1 (mild, moderate, severe) and between them and controls were all statistically significant (p < 0,001). No statistical differences between sites were observed (p > 0.05). The degree of muscle strength decline in dorsiflexion (eversion) were 60% (47%), 77% (71%), and 87% (83%) for DM1 with mild, moderate, and severe impairments, respectively. The smallest mean difference between all DM1 patients taking together was 2.3 Nm, a difference about twice than the standard error of measurement. There was a strong relationship between eversion and dorsiflexion strength profiles (R2 = 0,87;Quebec/0,80;Lyon). Using a 10-point scale, manual muscle testing could not discriminate between the 3 groups of DM1 patients.ConclusionsThe HHD protocol showed discriminative properties suitable for multicentre therapeutic trial. The present results confirmed the capacity of quantitative muscle testing to discriminate between healthy and DM1 patients with different levels of impairments. This study is a preliminary step for the implementation of a valid, reliable and responsive clinical outcome for the measurement of muscle impairments with this population.

Report of the first Outcome Measures in Myotonic Dystrophy type 1 (OMMYD-1) international workshop: Clearwater, Florida, November 30, 2011

Groupe de recherche interdisciplinaire en maladies neuromusculaires (GRIMN), Centre de sante et de services sociaux de Jonquiere, Quebec, Canada Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Quebec, Canada Department of Neurology, University of Milan, IRCCS Policlinico San Donato, Italy Human Genetics Unit, Centre hospitalier de l’Universite Laval, Quebec, Canada e ECOBES, Cegep de Jonquiere, Quebec, Canada Centre hospitalier universitaire de Chicoutimi, Chicoutimi, Quebec, Canada Department of Health Sciences, Universite du Quebec a Chicoutimi, Quebec, Canada Faculty of Medicine, Universite Laval, Quebec, Canada Canadian Forces Health Services HQ, Directorate of Medical Policy, Quebec, Canada

Report of the second Outcome Measures in Myotonic Dystrophy type 1 (OMMYD-2) international workshop San Sebastian, Spain, October 16, 2013

Report of the second Outcome Measures in Myotonic Dystrophy type 1 (OMMYD-2) international workshop San Sebastian, Spain, October 16, 2013 Cynthia Gagnon *, Giovanni Meola , Luc J. Hebert , Luc Laberge , Mario Leone , Chad Heatwole i a Groupe de Recherche Interdisciplinaire sur les Maladies Neuromusculaires (GRIMN), Centre de Sante et de Services Sociaux de Jonquiere, Jonquiere, Quebec, Canada b Faculty of Medicine and Health Sciences, Universite de Sherbrooke, Sherbrooke, Quebec, Canada c Department of Neurology, IRCCS Policlinico San Donato, University of Milan, Milan, Italy d Faculty of Medicine, Universite Laval, Laval, Quebec, Canada e Centre for Interdisciplinary Research in Rehabilitation and Social Integration (CIRRIS), Quebec, Quebec, Canada f ECOBES, Cegep de Jonquiere, Jonquiere, Quebec, Canada g Centre Hospitalier Universitaire de Chicoutimi, Chicoutimi, Quebec, Canada h Department of Health Sciences, Universite du Quebec a Chicoutimi, Chicoutimi, Quebec, Canada i Department of Neurology, The University of Rochester Medical Center, Rochester, NY, USA Received 19 December 2014

MRI of Tibialis Anterior Skeletal Muscle in Myotonic Dystrophy Type 1

OBJECTIVE The aim of this study was to evaluate whether magnetic resonance imaging (MRI) can be used as a noninvasive approach to assessment of disease severity and muscle damage in Myotonic Dystrophy type 1 (DM1). METHODS The MRI findings in legs of 41 patients with DM1 were evaluated with respect to the tibialis anterior (TA) skeletal muscle impairment. Magnetic resonance imaging findings were compared with TA strength measurements obtained by quantitative manual testing, duration of the disease and with the length of the CTG repeats. RESULTS Muscle MRI abnormalities were observed in 80% of DM1 patients, ranging from edema-like abnormalities alone to severe atrophy/fatty replacement. Edema-like abnormalities seem to be an earlier MRI marker of the disease. Fatty infiltration/atrophy correlated with the TA muscle force (r = 0.95), the severity (P = 0.00001) of the disease but not with the duration of the disease (P = 0.3) or the length of the CTG repeats (P > 0.10), measured in peripheral leukocytes. Evaluation of other muscles of the legs revealed that the medial gastrocnemius and soleus muscles were the most frequently and severely affected muscles, while tibialis posterior muscles were relatively spared. Edema-like abnormalities are most frequently observed in the skeletal muscles of the anterior compartment. CONCLUSION Muscle MRI is helpful to depict muscle abnormalities but does not seem to be a reliable indicator of skeletal muscle involvement in DM1 since the decrease in TAmuscle force is not correlated with MRI abnormalities in some patients.