[
research report
]
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
MARCELA BEMBO DE SOUZA, UG1 • JAQUELINE MARTINS, PT, MSc1 GISELE HARUMI HOTTA, PT1 • ANAMARIA SIRIANI DE OLIVEIRA, PT, PhD1
Measurement Properties of the Brazilian Version of the Penn Shoulder Score (PSS-Brazil): Reliability, Validity, and Responsiveness
S
houlder disorders are the third most prevalent musculoskeletal condition after spine and knee pain.24 For evaluating patients with shoulder pain, health-related patient-reported outcomes are considered essential,15 as they assess disease impact on
health-related quality of life and assist in clinical decision making.15 A number of shoulder-specific quesTTSTUDY DESIGN: Clinical measurement.
TTOBJECTIVES: To determine the reliability, validity, and responsiveness of the Brazilian version of the Penn Shoulder Score (PSS-Brazil) in patients with shoulder dysfunctions.
TTBACKGROUND: Several questionnaires assessing shoulder dysfunctions are available in Brazil, but the measurement properties of most of them, such as the PSS, have not yet been tested.
TTMETHODS: Internal consistency, measurement error, construct validity, and floor and ceiling effects were evaluated in 62 patients, 36 of whom completed the questionnaire at baseline and after 2 to 7 days to assess test-retest reliability. Responsiveness was determined with 50 patients who completed the questionnaire at an initial visit and after 4 weeks of physical therapy.
TTRESULTS: The PSS-Brazil displayed acceptable
internal consistency, with a Cronbach alpha of .92. Test-retest reliability was excellent, with an intraclass
tionnaires have been developed.1 However, the usefulness of these tools depends on their reliability, validity, and responcorrelation coefficient of 0.95; the standard error of measurement and minimal detectable change were 12.8 and 14.4 points, respectively. A high correlation was obtained between the PSS and the Shoulder Pain and Disability Index (0.96) and the Disabilities of the Arm, Shoulder and Hand questionnaire (0.86). There was moderate correlation between the PSS and its subscales and the pain and function subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey (0.40-0.68). There was high responsiveness, with an effect size of 0.95 and standardized response mean of 1.13 for patients with improvement of shoulder dysfunction, and adequate area under the curve of 0.81. No floor or ceiling effects were observed.
TTCONCLUSION: The PSS-Brazil is a reliable,
valid, and responsive measure for assessing patients with shoulder dysfunction. J Orthop Sports Phys Ther 2015;45(2):137-142. Epub 8 Jan 2015. doi:10.2519/jospt.2015.5165
TTKEY WORDS: clinimetrics, outcome measures, shoulder
siveness, as established by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN).26 The Penn Shoulder Score (PSS) is a valid, reliable, and responsive self-report questionnaire used to assess patients with various shoulder disorders.10 To date, the PSS has been translated and culturally adapted only for Brazil, but the measurement properties of the Brazilian version (PSS-Brazil) have not yet been tested.17 Therefore, the aim of this study was to determine the measurement properties of the PSS-Brazil for patients with shoulder disorders.
METHODS Participants
A
convenience sample of patients with shoulder disorders was recruited from the physiotherapy service of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo, Brazil. Patients 18 years of age or older who were diagnosed with shoulder dysfunctions were included. Patients were excluded if they had difficulty understanding the questionnaire (n
Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil. This study received financial support from the State of São Paulo Research Foundation (process number 2012/00169-2) and from the National Council for Scientific and Technological Development (process number 145814/2011-4). This study was approved by the Ethics in Research Committee of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo (reference number 14228/2011). This study did not require public trials registry. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address correspondence to Dr Anamaria Siriani de Oliveira, Prédio da Fisioterapia e Terapia Ocupacional da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Avenida Bandeirantes, 3900, Bairro Monte Alegre, CEP 14049-900 Ribeirão Preto/SP, Brazil. E-mail: [email protected] t Copyright ©2015 Journal of Orthopaedic & Sports Physical Therapy® 1
journal of orthopaedic & sports physical therapy | volume 45 | number 2 | february 2015 | 137
45-02 de Souza.indd 137
1/22/2015 10:56:36 AM
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
[ = 2 [both elderly patients over 90 years of age]), neurological diseases, systemic inflammatory conditions, dysfunctions in other structures of the upper limb, or if they were patients with postoperative shoulders. The study was approved by the Ethics in Research Committee of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo (reference number 14228/2011). Informed consent was obtained, and the rights of subjects were protected.
]
research report TABLE 1 Variable
Baseline Summary for Subjects With Shoulder Disorders* Phase 1 (n = 62)
Phase 2 (n = 50)
49.9 16.5
52.3 15.4
Male
31 (50)
19 (38)
Female
31 (50)
31 (62)
Mean SD age, y Sex
Affected shoulder Dominant
29 (46.8)
25 (50)
Nondominant
19 (30.6)
13 (26)
Bilateral
14 (22.6)
12 (24)
Employment status
Self-Report Measures
Employed
23 (37.1)
22 (44)
The PSS-Brazil was compared with well-validated Brazilian Portuguese questionnaires.1,21 The PSS assesses pain (3 items) and satisfaction (1 item) on an 11-point numeric rating scale, ranging from 0 (no pain/not satisfied) to 10 (worst possible pain/very satisfied), and assesses function (20 items) on a 4-category Likert scale, with response options ranging from 0 (can’t do at all) to 3 (no difficulty). The total PSS score ranges from 0 to 100, with higher scores indicating better shoulder status.1,10 Potential benefits of the PSS are that it includes items that address patient satisfaction and that cross a spectrum of contexts for pain and function. The Shoulder Pain and Disability Index (SPADI)13 measures pain and disability in patients with shoulder dysfunction through 13 items graded on a numeric rating scale from 0 to 10. The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire20 measures physical disability and symptoms of the entire upper limb through 30 items scored on a 5-point Likert scale. Both SPADI and DASH scores range between 0 and 100, with higher scores indicating worse shoulder-related quality of life.13,20 The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) measures overall health-related quality-of-life status in 8 domains, 3 of which were used in this study: physical functioning, bodily pain, and mental health. The total score
Employed but work suspended
15 (24.2)
11 (22)
Not employed (student)
12 (19.4)
9 (18)
Retired
12 (19.4)
8 (16)
Time since injury 6 mo
35 (56.5)
32 (64)
32 (51.6)
29 (58)
Shoulder disorders Impingement/rotator cuff tear Shoulder instability
9 (14.5)
5 (10)
Acromioclavicular separation
3 (4.8)
0 (0)
Proximal humerus fracture
9 (14.5)
11 (22)
Clavicle fracture or pseudarthrosis
3 (4.8)
4 (8)
Other
6 (9.7)
1 (2)
*Values are n (%) unless otherwise indicated.
of the SF-36 and each of its subscales ranges from 0 to 100, with higher scores indicating better quality of life.2,21
Study Protocol Psychometric properties were evaluated in 2 phases. In phase 1, 62 patients completed the PSS-Brazil, SPADI, DASH, and SF-36 questionnaires in random order at their initial visit. After 2 to 7 days, under similar conditions to the first visit, the PSS-Brazil was reapplied, and the patients completed the 7-point global rating of change (GROC) scale based on the question, “Since your first visit here, do you feel that your shoulder is slightly better (+1), moderately better (+2), much better (+3), extraordinarily better (+4), the same (0), worse (−1), or much worse (−2)?” The data were used to as-
sess reliability and construct validity, and only patients with a stable GROC score (score of 0) were analyzed for test-retest reliability. In phase 2, 50 patients completed, in random order, the PSS-Brazil, SPADI, and DASH during an initial visit; after 4 weeks of physical therapy, all questionnaires were readministered alongside the GROC, which divided the sample into 2 groups, those who reported improvement (score of +2 or greater) and no improvement (score of +1 or less) in shoulder dysfunction. These data were used for responsiveness analysis.
Data Analysis Demographic data and questionnaire scores were presented as the mean and standard deviation or frequencies, and
138 | february 2015 | volume 45 | number 2 | journal of orthopaedic & sports physical therapy
45-02 de Souza.indd 138
1/22/2015 10:56:36 AM
TABLE 2
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
Score
Scores on Instruments* Phase 1 Baseline
Phase 2 Baseline
4 wk
PSS-Brazil (0-100)
51.6 23.1
48.8 20.9
62.7 23.0
DASH (0-100)†
34.1 20.2
37.6 17.9
29.5 19.7
SPADI (0-100)
51.1 26.2
53.3 25.0
40.4 27.7
SF-36 pain (0-100)
44.9 21.3
NA
NA
SF-36 physical (0-100)
60.4 25.4
NA
NA
SF-36 mental (0-100)
65.0 25.6
NA
NA
Original PSS (0-100)‡
…
48.8 19.5
67.2 19.6
Abbreviations: DASH, Disabilities of the Arm, Shoulder and Hand questionnaire; NA, not applicable; PSS, Penn Shoulder Score; SF-36, Medical Outcomes Study 36-Item Short-Form Health Survey; SPADI, Shoulder Pain and Disability Index. *Values are mean SD. † The DASH was applied on a sample of 28 patients. ‡ Scores obtained from the study by Leggin et al.10
Measurement Properties of the Original Penn Shoulder Score 10
TABLE 3 Measurement Property Cronbach α (n = 178) ICC2,1 (n = 40) SEM (n = 178)
Total
Pain
Satisfaction
.93
…
…
Function …
0.94
0.88
0.93
0.93
8.5
3.8
1.3
6.1
MDC90 (n = 178)
12.1
5.2
1.8
8.6
MCID (n = 49)
11.4
NA
NA
NA
1.01
0.85
1.19
0.80
SRM (n = 104)
1.27
0.95
1.15
1.09
CSS, r (n = 40)
0.85
…
…
…
ASES, r (n = 40)
0.87
…
…
…
Effect size (n = 104)
Abbreviations: ASES, American Shoulder and Elbow Surgeons standardized shoulder assessment form; CSS, Constant Shoulder Score; ICC, intraclass correlation coefficient; MCID, minimal clinically important difference; MDC, minimal detectable change; NA, not applicable; SEM, standard error of measurement; SRM, standardized response mean.
the analyses were performed using SPSS Version 17 for Windows (SPSS Inc, Chicago, IL). Reliability was analyzed by internal consistency, test-retest reliability, and measurement error.26 Internal consistency was calculated using Cronbach alpha, with values between .70 and .95 considered adequate.25 Test-retest reliability was determined by the intraclass correlation coefficient (ICC2,1), with a 95% confidence interval,25 and the values were categorized as poor (less than 0.40), moderate (between 0.40 and 0.75), or excellent (greater than 0.75).6 Mea-
surement error was determined using the standard error of the measurement (SEM) and minimal detectable change (MDC) at 95% confidence interval levels. The SEM was calculated using the formula SEM = 1.96 ≈ SD ≈ √(1 – R), where SD is the standard deviation at baseline and R is the alpha value or, for satisfaction, the ICC. The MDC was calculated as MDC95 = SEM × √2.10 Construct validity was analyzed by evaluating whether the PSS-Brazil conformed to the expected relationships of high correlation (greater than 0.7) with the DASH and SPADI,8 the high-
est correlation being with the SPADI, a shoulder-specific questionnaire. The correlations of the PSS-Brazil to the SF36 and between their similar constructs were expected to be from 0.50 to 0.70.4 The satisfaction score was also expected to correlate moderately with the pain and function subscales of the SPADI and with the SF-36, as we assumed that the greater the shoulder pain or disability, the worse the patient’s satisfaction with their shoulder.7 Discriminant validity was evaluated by determining whether the expected weak relationship occurred between the PSS-Brazil and SF-36 mental health score.4 Knowngroups validity assessed the ability of the PSS-Brazil to discriminate between patients with subacromial impingement or rotator cuff tear and those with shoulder instability (SI),7 with the expectation that patients with SI would have different scores based on differences in their pathology.22 All correlations were performed using Pearson correlation coefficients and were classified as high (r≥0.70), moderate (r≥0.40 and r
research report
]
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
MARCELA BEMBO DE SOUZA, UG1 • JAQUELINE MARTINS, PT, MSc1 GISELE HARUMI HOTTA, PT1 • ANAMARIA SIRIANI DE OLIVEIRA, PT, PhD1
Measurement Properties of the Brazilian Version of the Penn Shoulder Score (PSS-Brazil): Reliability, Validity, and Responsiveness
S
houlder disorders are the third most prevalent musculoskeletal condition after spine and knee pain.24 For evaluating patients with shoulder pain, health-related patient-reported outcomes are considered essential,15 as they assess disease impact on
health-related quality of life and assist in clinical decision making.15 A number of shoulder-specific quesTTSTUDY DESIGN: Clinical measurement.
TTOBJECTIVES: To determine the reliability, validity, and responsiveness of the Brazilian version of the Penn Shoulder Score (PSS-Brazil) in patients with shoulder dysfunctions.
TTBACKGROUND: Several questionnaires assessing shoulder dysfunctions are available in Brazil, but the measurement properties of most of them, such as the PSS, have not yet been tested.
TTMETHODS: Internal consistency, measurement error, construct validity, and floor and ceiling effects were evaluated in 62 patients, 36 of whom completed the questionnaire at baseline and after 2 to 7 days to assess test-retest reliability. Responsiveness was determined with 50 patients who completed the questionnaire at an initial visit and after 4 weeks of physical therapy.
TTRESULTS: The PSS-Brazil displayed acceptable
internal consistency, with a Cronbach alpha of .92. Test-retest reliability was excellent, with an intraclass
tionnaires have been developed.1 However, the usefulness of these tools depends on their reliability, validity, and responcorrelation coefficient of 0.95; the standard error of measurement and minimal detectable change were 12.8 and 14.4 points, respectively. A high correlation was obtained between the PSS and the Shoulder Pain and Disability Index (0.96) and the Disabilities of the Arm, Shoulder and Hand questionnaire (0.86). There was moderate correlation between the PSS and its subscales and the pain and function subscales of the Medical Outcomes Study 36-Item Short-Form Health Survey (0.40-0.68). There was high responsiveness, with an effect size of 0.95 and standardized response mean of 1.13 for patients with improvement of shoulder dysfunction, and adequate area under the curve of 0.81. No floor or ceiling effects were observed.
TTCONCLUSION: The PSS-Brazil is a reliable,
valid, and responsive measure for assessing patients with shoulder dysfunction. J Orthop Sports Phys Ther 2015;45(2):137-142. Epub 8 Jan 2015. doi:10.2519/jospt.2015.5165
TTKEY WORDS: clinimetrics, outcome measures, shoulder
siveness, as established by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN).26 The Penn Shoulder Score (PSS) is a valid, reliable, and responsive self-report questionnaire used to assess patients with various shoulder disorders.10 To date, the PSS has been translated and culturally adapted only for Brazil, but the measurement properties of the Brazilian version (PSS-Brazil) have not yet been tested.17 Therefore, the aim of this study was to determine the measurement properties of the PSS-Brazil for patients with shoulder disorders.
METHODS Participants
A
convenience sample of patients with shoulder disorders was recruited from the physiotherapy service of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo, Brazil. Patients 18 years of age or older who were diagnosed with shoulder dysfunctions were included. Patients were excluded if they had difficulty understanding the questionnaire (n
Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil. This study received financial support from the State of São Paulo Research Foundation (process number 2012/00169-2) and from the National Council for Scientific and Technological Development (process number 145814/2011-4). This study was approved by the Ethics in Research Committee of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo (reference number 14228/2011). This study did not require public trials registry. The authors certify that they have no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the article. Address correspondence to Dr Anamaria Siriani de Oliveira, Prédio da Fisioterapia e Terapia Ocupacional da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Avenida Bandeirantes, 3900, Bairro Monte Alegre, CEP 14049-900 Ribeirão Preto/SP, Brazil. E-mail: [email protected] t Copyright ©2015 Journal of Orthopaedic & Sports Physical Therapy® 1
journal of orthopaedic & sports physical therapy | volume 45 | number 2 | february 2015 | 137
45-02 de Souza.indd 137
1/22/2015 10:56:36 AM
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
[ = 2 [both elderly patients over 90 years of age]), neurological diseases, systemic inflammatory conditions, dysfunctions in other structures of the upper limb, or if they were patients with postoperative shoulders. The study was approved by the Ethics in Research Committee of the Hospital das Clínicas of Ribeirão Preto Medical School, University of São Paulo (reference number 14228/2011). Informed consent was obtained, and the rights of subjects were protected.
]
research report TABLE 1 Variable
Baseline Summary for Subjects With Shoulder Disorders* Phase 1 (n = 62)
Phase 2 (n = 50)
49.9 16.5
52.3 15.4
Male
31 (50)
19 (38)
Female
31 (50)
31 (62)
Mean SD age, y Sex
Affected shoulder Dominant
29 (46.8)
25 (50)
Nondominant
19 (30.6)
13 (26)
Bilateral
14 (22.6)
12 (24)
Employment status
Self-Report Measures
Employed
23 (37.1)
22 (44)
The PSS-Brazil was compared with well-validated Brazilian Portuguese questionnaires.1,21 The PSS assesses pain (3 items) and satisfaction (1 item) on an 11-point numeric rating scale, ranging from 0 (no pain/not satisfied) to 10 (worst possible pain/very satisfied), and assesses function (20 items) on a 4-category Likert scale, with response options ranging from 0 (can’t do at all) to 3 (no difficulty). The total PSS score ranges from 0 to 100, with higher scores indicating better shoulder status.1,10 Potential benefits of the PSS are that it includes items that address patient satisfaction and that cross a spectrum of contexts for pain and function. The Shoulder Pain and Disability Index (SPADI)13 measures pain and disability in patients with shoulder dysfunction through 13 items graded on a numeric rating scale from 0 to 10. The Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire20 measures physical disability and symptoms of the entire upper limb through 30 items scored on a 5-point Likert scale. Both SPADI and DASH scores range between 0 and 100, with higher scores indicating worse shoulder-related quality of life.13,20 The Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) measures overall health-related quality-of-life status in 8 domains, 3 of which were used in this study: physical functioning, bodily pain, and mental health. The total score
Employed but work suspended
15 (24.2)
11 (22)
Not employed (student)
12 (19.4)
9 (18)
Retired
12 (19.4)
8 (16)
Time since injury 6 mo
35 (56.5)
32 (64)
32 (51.6)
29 (58)
Shoulder disorders Impingement/rotator cuff tear Shoulder instability
9 (14.5)
5 (10)
Acromioclavicular separation
3 (4.8)
0 (0)
Proximal humerus fracture
9 (14.5)
11 (22)
Clavicle fracture or pseudarthrosis
3 (4.8)
4 (8)
Other
6 (9.7)
1 (2)
*Values are n (%) unless otherwise indicated.
of the SF-36 and each of its subscales ranges from 0 to 100, with higher scores indicating better quality of life.2,21
Study Protocol Psychometric properties were evaluated in 2 phases. In phase 1, 62 patients completed the PSS-Brazil, SPADI, DASH, and SF-36 questionnaires in random order at their initial visit. After 2 to 7 days, under similar conditions to the first visit, the PSS-Brazil was reapplied, and the patients completed the 7-point global rating of change (GROC) scale based on the question, “Since your first visit here, do you feel that your shoulder is slightly better (+1), moderately better (+2), much better (+3), extraordinarily better (+4), the same (0), worse (−1), or much worse (−2)?” The data were used to as-
sess reliability and construct validity, and only patients with a stable GROC score (score of 0) were analyzed for test-retest reliability. In phase 2, 50 patients completed, in random order, the PSS-Brazil, SPADI, and DASH during an initial visit; after 4 weeks of physical therapy, all questionnaires were readministered alongside the GROC, which divided the sample into 2 groups, those who reported improvement (score of +2 or greater) and no improvement (score of +1 or less) in shoulder dysfunction. These data were used for responsiveness analysis.
Data Analysis Demographic data and questionnaire scores were presented as the mean and standard deviation or frequencies, and
138 | february 2015 | volume 45 | number 2 | journal of orthopaedic & sports physical therapy
45-02 de Souza.indd 138
1/22/2015 10:56:36 AM
TABLE 2
Journal of Orthopaedic & Sports Physical Therapy® Downloaded from www.jospt.org at UCSF Lib & CKM/RSCS Mgmt on April 26, 2015. For personal use only. No other uses without permission. Copyright © 2015 Journal of Orthopaedic & Sports Physical Therapy®. All rights reserved.
Score
Scores on Instruments* Phase 1 Baseline
Phase 2 Baseline
4 wk
PSS-Brazil (0-100)
51.6 23.1
48.8 20.9
62.7 23.0
DASH (0-100)†
34.1 20.2
37.6 17.9
29.5 19.7
SPADI (0-100)
51.1 26.2
53.3 25.0
40.4 27.7
SF-36 pain (0-100)
44.9 21.3
NA
NA
SF-36 physical (0-100)
60.4 25.4
NA
NA
SF-36 mental (0-100)
65.0 25.6
NA
NA
Original PSS (0-100)‡
…
48.8 19.5
67.2 19.6
Abbreviations: DASH, Disabilities of the Arm, Shoulder and Hand questionnaire; NA, not applicable; PSS, Penn Shoulder Score; SF-36, Medical Outcomes Study 36-Item Short-Form Health Survey; SPADI, Shoulder Pain and Disability Index. *Values are mean SD. † The DASH was applied on a sample of 28 patients. ‡ Scores obtained from the study by Leggin et al.10
Measurement Properties of the Original Penn Shoulder Score 10
TABLE 3 Measurement Property Cronbach α (n = 178) ICC2,1 (n = 40) SEM (n = 178)
Total
Pain
Satisfaction
.93
…
…
Function …
0.94
0.88
0.93
0.93
8.5
3.8
1.3
6.1
MDC90 (n = 178)
12.1
5.2
1.8
8.6
MCID (n = 49)
11.4
NA
NA
NA
1.01
0.85
1.19
0.80
SRM (n = 104)
1.27
0.95
1.15
1.09
CSS, r (n = 40)
0.85
…
…
…
ASES, r (n = 40)
0.87
…
…
…
Effect size (n = 104)
Abbreviations: ASES, American Shoulder and Elbow Surgeons standardized shoulder assessment form; CSS, Constant Shoulder Score; ICC, intraclass correlation coefficient; MCID, minimal clinically important difference; MDC, minimal detectable change; NA, not applicable; SEM, standard error of measurement; SRM, standardized response mean.
the analyses were performed using SPSS Version 17 for Windows (SPSS Inc, Chicago, IL). Reliability was analyzed by internal consistency, test-retest reliability, and measurement error.26 Internal consistency was calculated using Cronbach alpha, with values between .70 and .95 considered adequate.25 Test-retest reliability was determined by the intraclass correlation coefficient (ICC2,1), with a 95% confidence interval,25 and the values were categorized as poor (less than 0.40), moderate (between 0.40 and 0.75), or excellent (greater than 0.75).6 Mea-
surement error was determined using the standard error of the measurement (SEM) and minimal detectable change (MDC) at 95% confidence interval levels. The SEM was calculated using the formula SEM = 1.96 ≈ SD ≈ √(1 – R), where SD is the standard deviation at baseline and R is the alpha value or, for satisfaction, the ICC. The MDC was calculated as MDC95 = SEM × √2.10 Construct validity was analyzed by evaluating whether the PSS-Brazil conformed to the expected relationships of high correlation (greater than 0.7) with the DASH and SPADI,8 the high-
est correlation being with the SPADI, a shoulder-specific questionnaire. The correlations of the PSS-Brazil to the SF36 and between their similar constructs were expected to be from 0.50 to 0.70.4 The satisfaction score was also expected to correlate moderately with the pain and function subscales of the SPADI and with the SF-36, as we assumed that the greater the shoulder pain or disability, the worse the patient’s satisfaction with their shoulder.7 Discriminant validity was evaluated by determining whether the expected weak relationship occurred between the PSS-Brazil and SF-36 mental health score.4 Knowngroups validity assessed the ability of the PSS-Brazil to discriminate between patients with subacromial impingement or rotator cuff tear and those with shoulder instability (SI),7 with the expectation that patients with SI would have different scores based on differences in their pathology.22 All correlations were performed using Pearson correlation coefficients and were classified as high (r≥0.70), moderate (r≥0.40 and r
