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Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27. Published in final edited form as: Indian J Physiother Occup Ther. 2012 ; 6(3): 76–81.
Reliability and Concurrent Validity of Dynamic Rotator Stability Test–A Cross Sectional study K V Binoy Mathew* [Clinical Instructor cum Lecturer], Charu Eapen** [Associate Professor], and P. Senthil Kumar*** [Associate Professor] *College
of Physiotherapy, Medical Trust Institute of Medical Sciences, Kochi, Kerala
**Kasturba
Medical College Hospital, Mangalore, Karnataka
Author Manuscript
***Kasturba
Medical College Hospital, Mangalore, Karnataka
Abstract Purpose of the study—To find intra rater and inter rater reliability of Dynamic Rotator Stability Test (DRST) and to find concurrent validity of Dynamic Rotator Stability Test (DRST) with University of Pennsylvania Shoulder Score (PENN) Scale. Material and method—40 subjects of either gender between the age group of 18–70 with painful shoulder conditions of musculoskeletal origin was selected through convenient sampling. Tester 1 and tester 2 administered DRST and PENN scale randomly. In a subgroup of 20 subjects DRST was administered by both the testers to find the inter rater reliability. 180° Standard Universal Goniometer was used to take measurements.
Author Manuscript
Results—For intra-rater reliability, all the test variables were showing highly significant correlation (p=.94 – 1). For inter -rater, with tester 2, test variables like position, ROM, force, direction of abnormal translation, pain during the test, compensatory movement during test were found to be significant (p=.71–1).only some variables of DRST showed significant correlation with PENN scale (P=.320–.450) Conclusion—Dynamic Rotator Stability Test has good intra rater and moderate inter rater reliability. Concurrent validity of Dynamic Rotator Stability Test was found to be poor when compared to PENN Shoulder Score. Keywords Dynamic Rotator Stability Test; Shoulder; Instability; Rotator cuff
Author Manuscript
Introduction Shoulder pain is estimated to be the third most common cause of musculoskeletal consultation in primary care.1 The incidence of shoulder pain is quite high.2 Shoulder pain often impairs the ability to sleep, and restricted and/or painful range of motion of the shoulder influences performance of activities of daily living.3 Four basic mechanical abnormalities causing pain at the shoulder are stiffness, instability, weakness, and
Binoy Mathew et al.
Page 2
Author Manuscript
roughness. Instability is a functional complaint. Asymmetry, reproduction of symptoms, and apprehension are possible signs of instability.4 The shoulder joint instability occurs due to an imbalance in the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intraarticular pressure, the glenoid labrum, and the Gleno-humeral ligaments along with the joint capsule provide mainly end range stability.5 The dynamic stabilizing structures include the rotator cuff muscles and other shoulder muscles. Mid-range stability is provided by rotator cuff muscles by ‘concavity compression’.6
Author Manuscript
Failure of function of rotator cuff muscles in their stabilizing role leads to creation of an abnormal axis of rotation and abnormal translation of the head of humerus.7 Excessive translation of the humeral head along the glenoid results in pain and functional impairment.8 Commonly used tests for shoulder joint stability were mostly done at end range or mid range which were passive and assess only integrity of the capsular and ligamentous structures.9 Recent research findings have shown the need to consider dynamic joint stability and the local muscle system in the treatment of segmental spinal pain.10 Strong evidence is available that pain alters the timing of contraction in stabilizing muscles – transversus abdominis and multifidus in relation to the lumbar spine,vastus medialis obliquus in relation to the knee.6 Tests to detect lumbar and cervical dynamic stability are routinely used in clinical practice.11
Author Manuscript
Such tests developed to assess and treat dynamic stability of the shoulder is Dynamic Rotator Stability Test and Dynamic Relocation Test developed by Mary Magarey and Mark Jones.6, 11 DRST is more important for assessment of humeral head translation due to abnormal rotator cuff activity and the test involves multiple positions which might mimic function. In order for any type of measurement tool to be used with confidence when making decisions regarding patient care, the psychometric or measurement properties of reliability, validity, and responsiveness must be established.12 To date, research on reliability and validity and on establishing normative values for DRST is incomplete.6,11 But no study has been published which confirms reliability and validity of this test.13 The purpose of this study is to find reliability and concurrent validity of Dynamic Rotator Stability Test in subjects with painful shoulder.
Author Manuscript
Methodology Source of data Department of physiotherapy KMC Hospitals, Mangalore.
Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27.
Binoy Mathew et al.
Page 3
Study design
Author Manuscript
Cross sectional design for which ethical clearance granted by the institutional ethical committee Subjects 40 subjects of either gender between the age group of 18–70 with painful shoulder conditions of musculoskeletal origin referred to KMC Hospitals, Attavar and Ambedkar Circle were recruited for the study. Inclusion criteria
Author Manuscript
1.
Subjects with painful shoulder of musculoskeletal origin
2.
Availability of active shoulder ROM up to 120°
3.
Subjects with pain, apprehension or click with active shoulder movement.
4.
Willingness to participate in the study
5.
Capable of understanding instructions given by the tester.
Exclusion criteria
Author Manuscript
1.
History of recent fracture of the shoulder complex
2.
History of recurrent shoulder dislocation
3.
Subjects with diagnosed neurological problems pertaining to trunk and upper extremity
4.
Worsening of symptoms or high irritability with movement of shoulder complex.
Procedure Dynamic Rotator Stability Test (DRST) The subject seated on a stool. The therapist holds around the head of the humerus as shown in the figure.(Fig:2)
Author Manuscript
The test is done as described by Mary Magarey and Mark Jones.11The movement is done first in Scaption between 0–120 degrees.(Fig:1) All the movements are started in internal rotation direction(Fig:3); later movement to external rotation is done. The force initially used is isometric (30% of max. voluntary contraction force).As progression free active (Fig: 4), resisted concentric and eccentric force is used. If no abnormal humeral head translation is detected in Scaption, the test progress to flexion (sagittal) and abduction (coronal) plane. The test stops at the position where abnormal translation is detected and measurement is taken using Goniometer. (Fig: 5) University Of Pennsylvania Shoulder Score (Penn) Scale. 12 Penn Scale,100-point self-report scale consisting of 3 sections: pain, satisfaction, and function. There are 3 questions regarding pain (30 points), 1 regarding satisfaction of
Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27.
Binoy Mathew et al.
Page 4
Author Manuscript
shoulder function (10 points), and 20 regarding function (60 points). Measurement properties have been established for the Penn scale in patients with various shoulder pathologies.12 Prior to starting of study, testers underwent a habituation programme to habituate with the test variables or parameters of assessment in dynamic rotator stability test. Dynamic Rotator Stability Test was done in shoulders of 4 asymptomatic subjects of age between 20–25y. Penn shoulder score was also administered in a sample population of 40 asymptomatic subjects of either gender between the ages of 20–30 for cross cultural validation.14, 15 Subjects were selected through convenient sampling. Written informed consent was obtained after explaining them about the objectives and methodology of the study. Subjects were then screened using screening check-list for inclusion and exclusion criteria.
Author Manuscript
Part- I Reliability of DRST Order of the tester for the performance of DRST was randomized and the testers were blinded to each other’s findings. Part-II Validity-Concurrent Validity One tester evaluated the patient by administering score. Other tester did Dynamic Rotator Stability Test. Randomization of the tester was done for selected test for each subject. Each tester was blinded to other tester’s finding. Only one trial of assessment was done.
Statistical analysis Author Manuscript
All statistical testing was carried out using Statistical Package for Social Science version 13.0 software. Differences were considered statistically significant at p
Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27. Published in final edited form as: Indian J Physiother Occup Ther. 2012 ; 6(3): 76–81.
Reliability and Concurrent Validity of Dynamic Rotator Stability Test–A Cross Sectional study K V Binoy Mathew* [Clinical Instructor cum Lecturer], Charu Eapen** [Associate Professor], and P. Senthil Kumar*** [Associate Professor] *College
of Physiotherapy, Medical Trust Institute of Medical Sciences, Kochi, Kerala
**Kasturba
Medical College Hospital, Mangalore, Karnataka
Author Manuscript
***Kasturba
Medical College Hospital, Mangalore, Karnataka
Abstract Purpose of the study—To find intra rater and inter rater reliability of Dynamic Rotator Stability Test (DRST) and to find concurrent validity of Dynamic Rotator Stability Test (DRST) with University of Pennsylvania Shoulder Score (PENN) Scale. Material and method—40 subjects of either gender between the age group of 18–70 with painful shoulder conditions of musculoskeletal origin was selected through convenient sampling. Tester 1 and tester 2 administered DRST and PENN scale randomly. In a subgroup of 20 subjects DRST was administered by both the testers to find the inter rater reliability. 180° Standard Universal Goniometer was used to take measurements.
Author Manuscript
Results—For intra-rater reliability, all the test variables were showing highly significant correlation (p=.94 – 1). For inter -rater, with tester 2, test variables like position, ROM, force, direction of abnormal translation, pain during the test, compensatory movement during test were found to be significant (p=.71–1).only some variables of DRST showed significant correlation with PENN scale (P=.320–.450) Conclusion—Dynamic Rotator Stability Test has good intra rater and moderate inter rater reliability. Concurrent validity of Dynamic Rotator Stability Test was found to be poor when compared to PENN Shoulder Score. Keywords Dynamic Rotator Stability Test; Shoulder; Instability; Rotator cuff
Author Manuscript
Introduction Shoulder pain is estimated to be the third most common cause of musculoskeletal consultation in primary care.1 The incidence of shoulder pain is quite high.2 Shoulder pain often impairs the ability to sleep, and restricted and/or painful range of motion of the shoulder influences performance of activities of daily living.3 Four basic mechanical abnormalities causing pain at the shoulder are stiffness, instability, weakness, and
Binoy Mathew et al.
Page 2
Author Manuscript
roughness. Instability is a functional complaint. Asymmetry, reproduction of symptoms, and apprehension are possible signs of instability.4 The shoulder joint instability occurs due to an imbalance in the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intraarticular pressure, the glenoid labrum, and the Gleno-humeral ligaments along with the joint capsule provide mainly end range stability.5 The dynamic stabilizing structures include the rotator cuff muscles and other shoulder muscles. Mid-range stability is provided by rotator cuff muscles by ‘concavity compression’.6
Author Manuscript
Failure of function of rotator cuff muscles in their stabilizing role leads to creation of an abnormal axis of rotation and abnormal translation of the head of humerus.7 Excessive translation of the humeral head along the glenoid results in pain and functional impairment.8 Commonly used tests for shoulder joint stability were mostly done at end range or mid range which were passive and assess only integrity of the capsular and ligamentous structures.9 Recent research findings have shown the need to consider dynamic joint stability and the local muscle system in the treatment of segmental spinal pain.10 Strong evidence is available that pain alters the timing of contraction in stabilizing muscles – transversus abdominis and multifidus in relation to the lumbar spine,vastus medialis obliquus in relation to the knee.6 Tests to detect lumbar and cervical dynamic stability are routinely used in clinical practice.11
Author Manuscript
Such tests developed to assess and treat dynamic stability of the shoulder is Dynamic Rotator Stability Test and Dynamic Relocation Test developed by Mary Magarey and Mark Jones.6, 11 DRST is more important for assessment of humeral head translation due to abnormal rotator cuff activity and the test involves multiple positions which might mimic function. In order for any type of measurement tool to be used with confidence when making decisions regarding patient care, the psychometric or measurement properties of reliability, validity, and responsiveness must be established.12 To date, research on reliability and validity and on establishing normative values for DRST is incomplete.6,11 But no study has been published which confirms reliability and validity of this test.13 The purpose of this study is to find reliability and concurrent validity of Dynamic Rotator Stability Test in subjects with painful shoulder.
Author Manuscript
Methodology Source of data Department of physiotherapy KMC Hospitals, Mangalore.
Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27.
Binoy Mathew et al.
Page 3
Study design
Author Manuscript
Cross sectional design for which ethical clearance granted by the institutional ethical committee Subjects 40 subjects of either gender between the age group of 18–70 with painful shoulder conditions of musculoskeletal origin referred to KMC Hospitals, Attavar and Ambedkar Circle were recruited for the study. Inclusion criteria
Author Manuscript
1.
Subjects with painful shoulder of musculoskeletal origin
2.
Availability of active shoulder ROM up to 120°
3.
Subjects with pain, apprehension or click with active shoulder movement.
4.
Willingness to participate in the study
5.
Capable of understanding instructions given by the tester.
Exclusion criteria
Author Manuscript
1.
History of recent fracture of the shoulder complex
2.
History of recurrent shoulder dislocation
3.
Subjects with diagnosed neurological problems pertaining to trunk and upper extremity
4.
Worsening of symptoms or high irritability with movement of shoulder complex.
Procedure Dynamic Rotator Stability Test (DRST) The subject seated on a stool. The therapist holds around the head of the humerus as shown in the figure.(Fig:2)
Author Manuscript
The test is done as described by Mary Magarey and Mark Jones.11The movement is done first in Scaption between 0–120 degrees.(Fig:1) All the movements are started in internal rotation direction(Fig:3); later movement to external rotation is done. The force initially used is isometric (30% of max. voluntary contraction force).As progression free active (Fig: 4), resisted concentric and eccentric force is used. If no abnormal humeral head translation is detected in Scaption, the test progress to flexion (sagittal) and abduction (coronal) plane. The test stops at the position where abnormal translation is detected and measurement is taken using Goniometer. (Fig: 5) University Of Pennsylvania Shoulder Score (Penn) Scale. 12 Penn Scale,100-point self-report scale consisting of 3 sections: pain, satisfaction, and function. There are 3 questions regarding pain (30 points), 1 regarding satisfaction of
Indian J Physiother Occup Ther. Author manuscript; available in PMC 2015 August 27.
Binoy Mathew et al.
Page 4
Author Manuscript
shoulder function (10 points), and 20 regarding function (60 points). Measurement properties have been established for the Penn scale in patients with various shoulder pathologies.12 Prior to starting of study, testers underwent a habituation programme to habituate with the test variables or parameters of assessment in dynamic rotator stability test. Dynamic Rotator Stability Test was done in shoulders of 4 asymptomatic subjects of age between 20–25y. Penn shoulder score was also administered in a sample population of 40 asymptomatic subjects of either gender between the ages of 20–30 for cross cultural validation.14, 15 Subjects were selected through convenient sampling. Written informed consent was obtained after explaining them about the objectives and methodology of the study. Subjects were then screened using screening check-list for inclusion and exclusion criteria.
Author Manuscript
Part- I Reliability of DRST Order of the tester for the performance of DRST was randomized and the testers were blinded to each other’s findings. Part-II Validity-Concurrent Validity One tester evaluated the patient by administering score. Other tester did Dynamic Rotator Stability Test. Randomization of the tester was done for selected test for each subject. Each tester was blinded to other tester’s finding. Only one trial of assessment was done.
Statistical analysis Author Manuscript
All statistical testing was carried out using Statistical Package for Social Science version 13.0 software. Differences were considered statistically significant at p
