IT IS WIDELY RECOGNIZED that the ability to position

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1 ORIGINAL ARTICLE Scapular Positioning in Patients With Shoulder Pain: A Study Examining the Reliability and Clinical Importance of 3 Clinical Tests Jo Nijs, PhD, MSc, Nathalie Roussel, PT, Kim Vermeulen, PT, Greet Souvereyns, PT ABSTRACT. Nijs J, Roussel N, Vermuelen K, Souvereyns G. Scapular positioning in patients with shoulder pain: a study examining the reliability and clinical importance of 3 clinical tests. Arch Phys Med Rehabil 2005;86: Objective: To examine the interobserver reliability, internal consistency, and clinical importance of 3 clinical tests for the assessment of scapular positioning in patients with shoulder pain. Design: Prospective repeated-measures design. Setting: Private practices for physical therapy and hospital outpatient physical therapy divisions. Participants: Twenty-nine patients with shoulder pain who were diagnosed by a physician as having a shoulder disorder. Interventions: Not applicable. Main Outcome Measures: Study participants filled in a visual analog scale for pain and the Shoulder Disability Questionnaire. Next, 2 assessors performed the following tests: the acromion and the table, measurement of the distance from the medial scapular border to the fourth thoracic spinous processes, and the lateral scapular slide test. Results: The interobserver reliability coefficients were greater than.88 (intraclass correlation coefficients) for the the acromion and the table, were greater than.50 for the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes, and were greater than.70 for the lateral scapular slide test. The Cronbach coefficient for internal consistency for all tests was.88. No associations between the outcome of the tests and self-reported pain severity or disability were found. Conclusions: These data provide evidence favoring the interobserver reliability of 2 of 3 tests for the assessment of scapular positioning in patients with shoulder pain. The clinical importance of the tests outcomes, however, is questionable. Key Words: Rehabilitation; Reliability and validity; Scapula by American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation From the Division of Musculoskeletal Physiotherapy, Department of Health Sciences, Hogeschool Antwerpen, Antwerp, Belgium (Nijs, Roussel, Vermeulen, Souvereyns) and Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium (Nijs). Supported by the Hogeschool Antwerpen, Antwerp, Belgium. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the author(s) is/are associated. Reprint requests to Jo Nijs, PhD, MSc, Campus HIKE, Dept G, Hogeschool Antwerpen, Van Aertselaerstraat 31, 2170 Merksem, Belgium, Jo.Nijs@vub.ac.be /05/ $30.00/0 doi: /j.apmr IT IS WIDELY RECOGNIZED that the ability to position the scapula at rest and during movements and tasks (scapular positioning) is essential for optimal upper-limb function. 1,2 Scapular positioning should be optimal in relation to both the thorax and the humerus. In relation to the humerus, optimal positioning is essential for appropriate positioning of the glenoid, which in turn guarantees maximal mobility and stability of the glenohumeral joint. From basic sciences like anatomy and movement analysis it can be concluded that the muscular system is the major contributor to scapular positioning both at rest and during functional tasks. In the case of altered muscle activity (delayed firing or increased tension and consequent shortening) of scapular muscles, however, scapular positioning is likely to become abnormal. Inappropriate control of scapular positioning has frequently been linked to the development of shoulder impingement syndrome, 2-6 and Ackermann et al 7 suggested a link with shoulder and neck problems in violinists. From a clinical perspective, however, guidelines for a reliable and valid assessment of faulty scapular positioning in patients with shoulder pain are currently unavailable. Hébert et al 2 concluded that simple clinical indicators should be developed to allow clinicians to assess scapular kinematic behavior accurately. The measurement of scapular protraction (intraclass correlation coefficient [ICC].97 [intrarater reliability]; ICC.96 [interrater reliability]) and scapular rotation (ICC.97 [intrarater and interrater reliability]) has good reliability and validity (statistically related to radiographic measurements) in 8 healthy subjects. 8 Host 3 described how scapular taping was able to improve the resting position of the scapula and the scapulothoracic joint movement in a patient with chronic shoulder pain. To quantify the resting scapular position, she used 2 clinical tests: measurement of the distance from the medial scapular border to the fourth thoracic spinous processes and measurement of the distance between the posterior border of the acromion and the table. No data addressing either the reliability or the validity of these tests are currently available. Host herself indicated that the normal distance from the medial scapular border to the thoracic spinous processes is believed to be 5.08 cm, but this value is not based on data or research findings. 3(p808) It has been suggested that the measurement of the distance between the posterior border of the acromion and the table is indicative of the length of the pectoralis minor muscle. 3 A short or overactive pectoralis minor muscle can maintain the scapula in an excessive protracted or downwardly rotated position (ie, pseudowinging, a frequently observed type of abnormal scapular positioning). 1 Likewise, the lateral scapular slide test () was designed by Kibler 9 to assess scapular asymmetry under varying loads (measurement of the distance between the inferior angle of the scapula and the closest spinous process in 0, 45, and 90 of abduction in the coronal plane). It was originally proposed that a side-to-side difference (asymmetry) greater than 1.5cm was indicative of shoulder dysfunction. 9 Experimental data, however, showed that asymmetric scapular position is commonly seen in asymptomatic subjects and that the cutoff value of 1.5cm has a low specificity. 10,11 Thus,

2 1350 SCAPULAR POSITIONING WITH SHOULDER PAIN, Nijs further studying of the reliability and validity of these 3 clinical tests for the assessment of scapular positioning (, measurement of the distance from the medial scapular border to the fourth thoracic spinous processes, measurement of the distance between the posterior border of the acromion and the table) was warranted. Therefore, this study aimed at (1) examining the interobserver reliability, (2) examining the internal consistency, and (3) examining the clinical importance of 3 clinical tests for the assessment of scapular positioning in patients with shoulder pain. To examine the clinical importance of the tests, we searched for associations between the outcome of the tests and self-reported pain severity and disability in patients with shoulder pain. Indeed, some impairments (ie, impairments in scapular positioning) may not be related to disability and therefore need not become a focus of treatment. 12,13 This is a difficult yet critical step in the clinical reasoning process. The Clinical Research Agenda for Physical Therapy 14 has identified the relation between impairments and disability as an extremely important question for the conduct of clinical practice. Furthermore, it was hypothesized that if the outcome on the clinical tests generates clinically relevant data, then the outcome would differ between the symptomatic and asymptomatic side. METHODS Subject Recruitment and Research Design A convenience sample of 29 patients with a variety of shoulder disorders, diagnosed by a physician, was recruited from 10 private practices for physical therapy (PT) and 4 hospital outpatient PT divisions. To be included in the trial, subjects had to be diagnosed as having a shoulder disorder by a physician, be referred by a physician for PT, and have shoulder pain at the time of the study. In addition, patients receiving PT for shoulder pain related to a recent surgical intervention were excluded. Blinding of assessors was deemed crucial for the examination of the research questions; scars due to a recent surgical intervention would prohibit blinding of the assessors (symptomatic side). Likewise, all subjects having a visible injury related to the shoulder pain (eg, a hematoma) were excluded from the study sample. Before study participation, all subjects received oral information about study. Next, an information leaflet was handed out to all participants, and they were instructed to read it carefully and, if applicable, to ask for additional clarification. Subjects able to provide written informed consent were then asked to fill in the Shoulder Disability Questionnaire (SDQ) 15,16 and a visual analog scale (VAS) for pain severity. Afterward, the first examiner assessed the patient. The following tests were performed in order of appearance: measurement of the distance between the posterior border of the acromion and the table (both with the shoulder girdle at rest and with active shoulder retraction), measurement of the distance from the medial scapular border to the fourth thoracic spinous processes (again, both at rest and with active shoulder retraction), and the. After the standardized assessment by the first examiner, the second examiner entered the room and performed the same tests. Both shoulders were assessed, and the investigators were blinded to both the symptomatic side and the outcome of the tests performed by the other assessor. When the study took place, the investigators held a bachelor s degree in PT and had completed their final year of the master s degree program in PT. In a 2-hour training session before data collection, the investigators were trained in performing the tests under supervision of 2 manual therapists. Self-Reported Measures The SDQ aims at assessing disability in patients with shoulder pain. In this study, we used the Dutch version of the SDQ. The SDQ is a self-administered questionnaire consisting of 16 items. For each item, the patient has 3 possible responses: shoulder pain during the activity included in the item, no pain during the activity of interest, or not applicable (if the patient did not perform the activity of interest during the past 24 hours). The overall score is the ratio of the painful activities versus the number of applicable items, multiplied by 100. Consequently, the overall scores vary from 0% to 100% disability. The time to administer the SDQ ranges from 5 to 10 minutes. The responsiveness ratio (calibrated responsiveness ratio) of the SDQ after 1 month was 2.22 and after 6 months was Data supporting the content validity of the SDQ have been reported as well. 16 From a systematic literature review on clinimetric evaluation of shoulder disability questionnaires, it was concluded that the construct validity of the SDQ is good, but data addressing the test-retest reliability are currently lacking. 17 The VAS (range, 0 100mm) was used to assess shoulder pain severity. The pain scores obtained with the VAS are believed to be reliable, 18,19 valid, 20 and sensitive to change. 19 Clinical Tests The measurement of the distance between the posterior border of the acromion and the table was performed as described by Host. 3 The patient was positioned supine and instructed to relax. In this position, the assessor measured the distance between the posterior border of the acromion and the table bilaterally (measured vertically with a tape measure as shown in fig 1). Afterward, this procedure was repeated with the patient actively retracting both shoulders. To achieve active bilateral shoulder retraction, the patient was instructed to actively move both shoulders toward the table surface. Next, the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes (fig 2) was performed as described by Host. 3 The test was performed with the patient standing and instructed to stay relaxed. Both the fourth thoracic spinous process and the medial scapular border were identified through palpation. The distance between Fig 1. The measurement of the distance between the posterior border of the acromion and the table surface with the patient supine.

3 SCAPULAR POSITIONING WITH SHOULDER PAIN, Nijs 1351 both anatomic landmarks was measured in the horizontal plane using a tape measure. Again, this procedure was repeated with the patient actively retracting both shoulders. To achieve active bilateral shoulder retraction, the patient was instructed to actively move both shoulders backward. The was designed by Kibler 9 to assess scapular asymmetry under varying loads. To maintain a consistent posture during the various test positions, subjects were instructed to fix their eyes on an object in the examination area. 11 For the first test position of the, the patient was instructed to keep the arms relaxed at his/her sides. When the test position was obtained and confirmed by the assessor, the most inferior aspect of the inferior angle of the scapula and the closest spinous process in the same horizontal plane were identified through palpation and marked. The distance between the 2 reference points was measured bilaterally with a tape measure. This procedure was repeated for test position 2 (the patient was instructed to actively place both hands on the ipsilateral hips, and consequently the humerus was positioned in medial rotation at 45 of abduction in the coronal plane) and test position 3 (the patient was instructed to actively extend both elbows and to elevate and maximally internally rotate [ thumbs down ] both arms at or below 90 in the coronal plane). Test positions 2 and 3 are illustrated in figures 3 and 4, respectively. Between test positions 2 and 3, the patient was instructed to reposition the upper extremities from the test position to neutral. Statistical Analysis All data were analyzed using SPSS, version 11.0, a for Windows. Appropriate descriptive statistics were used (mean, standard deviation [SD], standard error of the mean, and range for age, illness duration, VAS scores, SDQ scores, and the outcome on the 3 clinical tests; frequencies and percentage for gender and symptomatic side). For examining the interobserver reliability of the clinical tests, the ICC (2-way mixed-effect model) was used. 21,22 For interpretation of the ICCs, we used the threshold value of.70 to define fair reliability. 17 The Cronbach coefficient was computed to examine the internal consistency of the outcome of the clinical tests. For examining the clinical importance of the outcome of the clinical tests, we used 2 different statistical approaches. First, we used a Pearson Fig 3. The test, position 2. correlation analysis for examining the associations between the self-reported measures and the tests outcomes. Second, we compared the outcomes of the clinical tests between the symptomatic and asymptomatic side using a paired-samples Student t test. A 1-sample Kolmogorov-Smirnov goodness-of-fit test was used to examine whether the variables entering a Student t test and Pearson correlation analysis were normally distributed. The significance level was set at.01 to help protect against potential type I errors. RESULTS Twenty-nine patients with shoulder pain were recruited; 19 subjects were women (65.5%), and in 18 patients (62.1%) the right shoulder was affected. The mean age of the study sample was years (range,.18 81y), and the mean shoulder pain duration was months. The mean SDQ total scores ranged between 13% and 100% disability (mean total score SD, 58.3% 20.1%), and the mean VAS pain score Fig 2. The measurement of the distance from the medial scapular border to the fourth thoracic spinous with active bilateral shoulder retraction. Fig 4. The test, position 3.

4 1352 SCAPULAR POSITIONING WITH SHOULDER PAIN, Nijs Table 1: Descriptive Statistics of the Outcome on the 3 Clinical Tests for the Assessment of Scapular Positioning: Symptomatic Versus Asymptomatic Sides (Assessor 1) Test n Mean SD (mm) SEM Range (mm) t (P*) Acromion Table relaxed symptomatic side (.32) Table relaxed asymptomatic side Table retraction symptomatic side (.91) Table retraction asymptomatic side Scapula T4 relaxed symptomatic side (67) T4 relaxed asymptomatic side T4 retraction symptomatic side (.08) T4 retraction asymptomatic side Position 1 symptomatic side (.28) Position 1 asymptomatic side Position 2 symptomatic side (.20) Position 2 asymptomatic side Position 3 symptomatic side (.16) Position 3 asymptomatic side Abbreviations: SEM, standard error of the mean; T4, fourth thoracic spinous process. *Level of significance was set at.01 to help protect against potential type I errors. was mm (range, 4 62mm). The descriptive statistics of the outcome of the first assessor on the 3 clinical tests are presented in table 1, and for assessor 2 these data are presented in table 2. The interobserver ICCs of the measurement of the distance between the posterior border of the acromion and the table at rest and during active shoulder retraction were greater than.91 and.88, respectively (table 3). For the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes at rest and with active shoulder retraction, the ICCs were greater than.50 and.70, respectively. For positions 1, 2, and 3 of the, the ICCs were greater than.82,.86, and.70, respectively. Figure 5 shows the reliability data of the position 2 (right side), and figure 6 shows the reliability data of the measurement of the distance between the posterior border of the acromion and the table (relaxed left side). The Cronbach coefficient for internal consistency of the different tests included in the assessment of scapular positioning was.88 for both assessors. All variables were normally distributed (Kolmogorov-Smirnov test, P.05; data not shown). A Pearson correlation analysis showed a significant association between pain severity (VAS) and the SDQ total scores (r.61, P.001). The results of Pearson correlation analysis searching for associations between the self-reported measures (VAS, SDQ) and the outcome of the tests for the assessment of scapular positioning (symptomatic side) are shown in table 4. Using the data of either assessor 1 or assessor 2, we found no associations (P.01). The comparison of the outcome of the 3 clinical tests between the symptomatic and asymptomatic sides is presented in tables 1 and 2. Comparing the symptomatic versus the asymptomatic side, assessor 1 found higher mean values in the symptomatic side Table 2: Descriptive Statistics of the Outcome of the 3 Clinical Tests for the Assessment of Scapular Positioning: Symptomatic Versus Asymptomatic Sides (Assessor 2) Test n Mean SD (mm) SEM Range (mm) t (P*) Acromion Table relaxed symptomatic side (.24) Table relaxed asymptomatic side Table retraction symptomatic side (1.00) Table retraction asymptomatic side Scapula T4 relaxed symptomatic side (.51) T4 relaxed asymptomatic side T4 retraction symptomatic side (.01) T4 retraction asymptomatic side Position 1 symptomatic side (.07) Position 1 asymptomatic side Position 2 symptomatic side (.33) Position 2 asymptomatic side Position 3 symptomatic side (.39) Position 3 asymptomatic side *Level of significance was set at.01 to help protect against potential type I errors.

5 SCAPULAR POSITIONING WITH SHOULDER PAIN, Nijs 1353 Table 3: Interobserver Reliability of 3 Clinical Tests for the Assessment of Scapular Positioning Test n ICC* Posterior acromion Table relaxed left side Table relaxed right side Table retraction left side Table retraction right side Medial scapular border T4 relaxed left side T4 relaxed right side T4 retraction left side T4 retraction right side Position 1 left side Position 1 right side Position 2 left side Position 2 right side Position 3 left side Position 3 right side *Two-way mixed model. for 4 of 7 test positions, and assessor 2 found higher mean values for 6 of 7 test positions. However, no statistically significant differences were observed between the painful and the nonpainful shoulders (P.01). DISCUSSION The interobserver reliability of the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes with the shoulder relaxed was poor. However, it was shown that the interobserver reliability of the the acromion and the table at rest and during active shoulder Fig 5. Scatter diagram displaying the interobserver reliability data of the position 2, right side. Legend: x axis, assessor 1; y axis, assessor 2. Fig 6. Scatter diagram displaying the interobserver reliability data of the the acromion and the table (relaxed left side). Legend: x axis, assessor 1; y axis, assessor 2. retraction, the, and the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes with active shoulder retraction was fair. To our knowledge, this is the first study addressing the reliability of the the acromion and the table and the measurement of the distance from the medial scapular border to the fourth thoracic spinous processes in patients with shoulder pain. One study 23 examined the intrarater reliability of the horizontal distance from the medial border of the scapula to the third (not the fourth) thoracic spinous processes in healthy subjects (ICC.91). For positions 1, 2, and 3 of the, the ICCs were greater than.82,.86, and.70, respectively. These results are not in accordance with 2 previous studies, which found ICC values of.79,.45, and.57 for subjects with shoulder impairments 11 and even lower ICC values (range,.18.69) for asymptomatic subjects. 24 It is difficult to explain the differences in findings among various studies. Variation in training and clinical experience among examiners is unlikely to account for the observed discrepancies: the examiners of the Odom et al 11 study of shoulder patients had 4 to 7 years of experience in outpatient orthopedics, whereas the examiners in our study were senior PT students. These students received training before the study, but their skills may not be reflective of most experienced physical therapists and medical doctors who currently use these tests. One would therefore expect to find lower interobserver reliability between senior PT students than between experienced physical therapists (as was the case in the Odom 11 study). A study examining the intertester reliability of clinical tests of the sacroiliac joint concluded that the years of experience did not affect the reliability. 25 The internal consistency of these clinical tests was high for both assessors. This suggests that the 3 tests are assessing the same underlying construct and dimension. It is tempting to speculate that scapular positioning represents this construct.

6 1354 SCAPULAR POSITIONING WITH SHOULDER PAIN, Nijs Table 4: Correlations Between the Self-Reported Measures (VAS, SDQ) and the Outcome of the Tests for the Assessment of Scapular Positioning (N 29) Test Assessor 1 Assessor 2 r * SDQ (P ) r * VAS (P) r * SDQ (P) r * VAS (P) Distance posterior acromion Table relaxed.18 (.35).02 (.94).20 (.31).04 (.85) Table with active shoulder retraction.15 (.45).14 (.46).08 (.68).20 (.29) Distance medial scapular border T4 relaxed.04 (.85).13 (.49).08 (.67).20 (.29) T4 retraction.07 (.72).25 (.19).05 (.79).19 (.33) Position 1.01 (.98).24 (.22).02 (.92).11 (.59) Position 2.24 (.22).05 (.79).01 (.95).11 (.56) Position 3.16 (.40).02 (.93).01 (.97).08 (.68) *Pearson r correlation coefficient. Level of significance was set at.01 to help protect against potential type I errors. Future studies (criterion validity studies) are required to confirm this assumption. Lewis et al 26 showed that surface palpation of scapular position is a valid method for determining the actual location of the scapula, which in turn supports the use of scapular skin surface palpation as a component of the clinical tests of interest in our report. Further studying of the biometric properties of these clinical tests for the assessment of scapular positioning is still required. We found a significant association between pain severity and shoulder disability, measured with the SDQ (r.61). This observation provides evidence supporting the convergent validity of the Dutch version of the SDQ. We found no significant correlations between the self-reported measures and the outcome of the 3 scapular positioning tests. Together with the inability of any of the 3 tests to differentiate between the symptomatic and asymptomatic side, these observations question the clinical importance of the data obtained with the 3 clinical tests for the assessment of scapular positioning. The data outlined by Hébert et al 2 provide a hypothetical explanation for the lack of differences between the symptomatic and asymptomatic sides as observed in our report. Previous research has shown that in patients with shoulder impingement syndrome, the 3-dimensional scapular behavior does not differ between the symptomatic and asymptomatic sides. 2 However, when comparing the scapular behavior of the impingement syndrome patients with healthy subjects, Hébert concluded that both shoulders of the patients group presented with abnormal scapular positioning as compared with the healthy subjects. 2 Thus, further studying of the outcome of the clinical assessment of scapular positioning and associated shoulder disability, especially in comparison with asymptomatic healthy subjects, is warranted. In addition, although the tests used in our study are linear, scapular movements are 3-dimensional. Thus, using 3-dimensional tests for assessing scapular positioning may increase the probability of finding evidence that supports a role of scapular positioning in patients with shoulder pain. The results of our study should be interpreted in relation to the study limitations. The limited experience of the assessors has been discussed above, and one could argue that the sample size lacked strength to find significant associations between the self-reported measures and the scapular positioning tests outcomes. Because the correlation coefficients were very small (the majority were 0.2) and the corresponding P values did not come near to a trend toward statistical significance (P.05), we deemed a power analysis unnecessary. We conclude that the sample size did not affect the outcome of the correlation analysis. Furthermore, the patients included in the present study were recruited from different private practices for PT and hospital outpatient PT divisions and were referred by a physician for PT for their shoulder pain. Consequently, these subjects are likely to be representative of shoulder patients in general seen in outpatient PT settings. However, the study sample was not randomly allocated. CONCLUSIONS These data provide evidence favoring the interobserver reliability of 2 of 3 clinical tests for the assessment of scapular positioning in patients with shoulder pain. The internal consistency of the tests outcomes was high for both assessors, suggesting that the 3 tests assess the same underlying construct and dimension. The clinical importance of the tests outcomes, however, is questionable. Further work is required to provide clinicians with simple, reliable, and valid assessment techniques for scapular behavior in patients with shoulder pain. 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