Archives of Physical Medicine and Rehabilitation
Volume 87, Issue 9 , Pages 1242-1249, September 2006

Intraobserver Reliability of 4 Physiologic Movements of the Shoulder in Subjects With and Without Symptoms

  • Rachel E. Valentine, BSc, MCSP

      Affiliations

    • Therapy Department, Chelsea and Westminster Hospital, London, UK
    • ,
  • Jeremy S. Lewis, PhD, MCSP, MAPA, MMPA

      Affiliations

    • Therapy Department, Chelsea and Westminster Hospital, London, UK
    • Physiotherapy Department, St George’s Hospital, London, UK.
    • Corresponding Author InformationReprint requests to Jeremy S. Lewis, PhD, MCSP, MAPA, MMPA, Therapy Department, Chelsea and Westminster Hospital, 369 Fulham Rd, London, UK

Article Outline

Abstract 

Valentine RE, Lewis JS. Intraobserver reliability of 4 physiologic movements of the shoulder in subjects with and without symptoms.

Objective

To assess intraobserver reliability of 4 physiologic movements of the shoulder.

Design

Test-retest analyses. Blinded data entry.

Setting

Outpatient department in National Health Service teaching hospital.

Participants

Forty-five asymptomatic volunteers and 45 subjects with shoulder symptoms.

Interventions

Not applicable.

Main Outcome Measures

Intraclass correlation coefficients (ICC), 95% confidence intervals, and standard error (SE) of measurements for bilateral measurements of shoulder flexion and abduction (gravity dependent inclinometer), shoulder external rotation (tape measure), and shoulder internal rotation (visual estimation).

Results

For subjects without symptoms, single measure ICC results ranged from .85 to .96; SE of measurement results for the angular movements ranged from 2.1° to 2.8° and for the linear measurements 1.1 to 1.6cm. For subjects with symptoms, single measure ICC results ranged from .82 to .98; SE of measurement results for the angular movements ranged from 1.5° to 13.3° and for the linear measurements 1.3 to 1.6cm.

Conclusions

With the exception of painful shoulder flexion in the group of subjects with symptoms, the single-measure ICC results were very good to excellent and the highest SE of measurement values were 5.3° for the angular measurements and 1.6cm for the linear measurements. For clinicians involved in the management of subjects with shoulder symptoms, the SE of measurement results provide guidance as to the error associated with the individual measurements. Using the SE of measurement results, a clinician may determine if a clinically important change, be it negative or positive, has occurred as a result of any intervention offered.

Key Words:  Intraobserver variation , Outcome assessment (health care) , Range of motion, articular , Rehabilitation , Shoulder

 

MUSCULOSKELETAL DISORDERS of the shoulder are extremely common, with 1 in 3 people experiencing shoulder pain at some stage of their lives.1, 2 The clinical investigation of patients presenting with shoulder pathology involves: history taking, using appropriate outcome measurement scores, and assessing the shoulder with a series of clinical tests that include measuring the physiologic shoulder range of motion (ROM). Measuring ROM is a necessary and important part of the clinical examination, because deficiencies of physiologic movement have been reported in groups of patients whose shoulder pathology is associated with a traumatic onset, such as in sport, as well as those with no identifiable traumatic onset of symptoms.

Measuring shoulder ROM prior to, during, and at the end of a course of treatment provides the clinician with an indication of the effectiveness of the intervention. Randomized clinical trials investigating the effect of intervention on shoulder pathology have included measurements of shoulder ROM among the outcome measurements assessed to determine the effectiveness of the interventions.3, 4, 5 As such it is essential that reliable methods of measuring shoulder ROM that are easily accessible to clinicians are available to measure this component of shoulder function. The physiologic movements of the shoulder that are most commonly measured include flexion, abduction in the plane of the scapular, external rotation, internal rotation, and hand behind back.3, 4, 5, 6

Recommendations for measuring internal and external rotation of the shoulder involve placing the shoulder at 90° abduction while the patient is lying in the supine position.7, 8 Shoulder elevation in this range frequently provokes pain3, 5 and is therefore not appropriate for patients experiencing discomfort in this range. It would therefore be advantageous to have a reliable method of measuring both internal and external rotation with the arm by the side, which is generally a less provocative position. The assessment of hand behind back is recommended by the American Academy of Orthopaedic Surgeons and the Society of American Shoulder and Elbow Surgeons,9 because it is commonly described by patients as a maneuver associated with restriction of movement and pain, when dressing, attending to personal hygiene, and during other activities of daily living (ADLs). However, the movement of hand behind back should not be considered as an assessment of the ability of the shoulder to internally rotate. Mallon et al10 reported that measuring shoulder internal rotation by the maximal vertebral level reached by the patient’s thumb is an inexact method to measure this range. They conducted a radiologic analysis of the hand behind back movement in 8 subjects without shoulder symptoms and reported that internal rotation occurred at the glenohumeral joint when the arm was in front of the body and that scapulothoracic articulation contributed to the hand behind back maneuver by both extension (anterior tilt) and downward (internal) rotation of the scapula. They also reported from radiologic analysis that flexion at the elbow contributed substantially to the movement. In addition to this, Edwards et al11 argued that the range of hand behind back would be adversely influenced by conditions involving the elbow, wrist, or thumb. As such, it is not possible to determine the amount of glenohumeral internal rotation occurring during this movement. Furthermore, measurement error associated with determining the range of hand behind back by identifying the vertebral level reached by the extended thumb is substantial, with the level identified clinically differing by 1 to 2 spinal levels from the actual level.11 An alternative method to measure internal rotation of the shoulder has been proposed.9, 12 The method involves placing the subjects’ arm by the side of the body with the thumb facing laterally. The examiner palpates the medial and lateral epicondyles of the humerus with the thumb and index finger. The assumption is that in this position of the shoulder the interepicondylar line is in the frontal plane, and as the shoulder internally rotates the interepicondylar line also rotates internally (medially) from the frontal plane. A visual estimation of the amount of rotation from the starting position is recorded as the range of internal rotation. Although this is potentially an appealing method to measure shoulder internal rotation, a search of the literature failed to identify any study that has investigated the reliability of this method.

Other recommendations for the clinical measurement of shoulder ROM include tape measurements, goniometry, inclinometry, visual estimation, digital devices, and photography.7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19 Positions for measuring ROM have not been standardized, with recommendations including sitting in a chair with support,19 sitting without support, supine, side lying, prone, and standing.7, 8, 20 Other recommendations include measuring active range, passive range, range to the first onset of pain, and movement to the end of range. In clinical practice, the assessment of shoulder ROM is usually determined by visual estimation or goniometry. However, research findings suggest that these methods lack reliability21, 22 and these findings challenge the continuation of this method of assessment in clinical practice.

To be clinically meaningful, ROM reliability statistics need to include a combination of intraclass correlation coefficients (ICCs), 95% confidence intervals (CIs), and standard error (SE) of measurement. ICC results can range from 0 to 1, with minimal measurement error being associated with results closer to 1.23, 24, 25 ICC values between .75 and .9 indicate good reliability and values between .91 and 1 indicate adequate reliability for clinical measurements.26

ICC results in isolation should not be used as sole indicators of reliability; other reliability statistics, such as the 95% CI and the SE of measurement, provide additional meaningful methods of interpreting the reliability of a measurement.24, 27 The 95% CI presents a band of values that, with 95% confidence, contains the true reliability. A narrow CI suggests greater precision in the estimate of reliability. A higher “lower limit” for the CI suggests greater measurement reliability. The SE of measurement is calculated using the following formula: SE of measurement = SD √ (1 − ICC) (where SD is the standard deviation). It provides an interpretation of the reliability of a measurement that is expressed in the units of the measurement of interest, such as degrees or centimeters. As such, it is valuable for the clinician because it provides guidance as to whether the measured change is due to measurement error or to real (positive or negative) change.25, 28

The findings of shoulder ROM reliability studies are detailed in table 1.29 The findings from these studies suggest that no method of measurement has demonstrated sufficient reliability to be accredited as the clinical method of choice when assessing the shoulder ROMs. The implications of these findings are that shoulder ROM assessment and reassessment may be inaccurate, and determining if a change of ROM has occurred must be done with caution.

Table 1. Review of Studies Investigating the Reliability of Measuring Shoulder ROM
StudyMeasurementSubjectsMethodPositionIntrarater ReliabilityInterrater ReliabilityClinical Comment
Riddle et al13Flexion, passive⁎SShort goniometerVariableICC1,1=.98ICC1,1=.87SEM and 95% CI NR
Riddle et al13Flexion, passive⁎SLong goniometerVariableICC1,1=.98ICC1,1=.89SEM and 95% CI NR
Green et al17Flexion, active to P1SInclinometerSittingICC=.49ICC=.72SEM and 95% CI NR
Sabari et al34Flexion, passiveAS+?SGoniometerSupineICC2=.94 SEM and 95% CI NR
Sabari et al34Flexion, activeAS+?SGoniometerSupineICC2=.95 SEM and 95% CI NR
Sabari et al34Flexion, passiveAS+?SGoniometerSittingICC2=.95 SEM and 95% CI NR
Sabari et al34Flexion, activeAS+?SGoniometerSittingICC2=.97 SEM and 95% CI NR
Hayes et al18Flexion, passive to end ROMSVisualSittingICC2,1=.59, SEM=13°, 95% CI, ±26°ICC2,1=.70, SEM=19°, 95% CI, ±38°Not reliable
Hayes et al18Flexion, active to end ROMSGoniometerSittingICC2,1=.53, SEM=17°, 95% CI, ±34°ICC2,1=.69, SEM=25°, 95% CI, ±50°Not reliable
Riddle et al13Abduction, passive⁎SShort goniometerVariableICC1,1=.98ICC1,1=.84SEM and 95% CI NR
Riddle et al13Abduction, passive⁎SLong goniometerVariableICC1,1=.98ICC1,1=.87SEM and 95% CI NR
Croft et al21Abduction, passive to P1SDiagramNot stated ICC=.84SEM and 95% CI NR
Croft et al21Abduction, passive end ROMSDiagramNot stated ICC=.95SEM and 95% CI NR
Croft et al21Abduction, preselected rangeNot statedVisual ROPNot stated ICC=.99SEM and 95% CI NR
Green et al17Abduction, active to P1SInclinometerSittingICC=.38ICC=.77SEM and 95% CI NR
Sabari et al34Abduction, passiveAS+?SGoniometerSupineICC2=.98 SEM and 95% CI NR
Sabari et al34Abduction, activeAS+?SGoniometerSupineICC2=.99 SEM and 95% CI NR
Sabari et al34Abduction, passiveAS+?SGoniometerSittingICC2=.95 SEM and 95% CI NR
Sabari et al34Abduction, activeAS+?SGoniometerSittingICC2=.97 SEM and 95% CI NR
Hayes et al18Abduction, passive to end ROMSVisualSittingICC2,1=.60, SEM=21°, 95% CI, ±42°ICC2,1=.66, SEM=19°, 95% CI, ±38°Not reliable
Hayes et al18Abduction, active to end ROMSGoniometerSittingICC2,1=.58, SEM=23°, 95% CI, ±46°ICC2,1=.69, SEM=21°, 95% CI, ±38°Not reliable
de Winter et al35Abduction, passive†SElectronic inclinometerSitting ICC=.83 (affected side), ICC=.28 (CL side)Changes in ROM <20°−25° = possible ME
Riddle et al13ER, passive⁎SShort goniometerVariableICC1,1=.98ICC1,1=.90SEM and 95% CI NR
Riddle et al13ER, passive⁎SLong goniometerVariableICC1,1=.99ICC1,1=.88SEM and 95% CI NR
Croft et al21ER, passive to end ROMSDiagramNot stated ICC=.43Not reliable
Croft et al21ER, preselected rangeNot statedVisual ROPNot stated ICC=.37Not reliable
Green et al17ER, in neutral-active to P1SInclinometerSupineICC=.85ICC=.88SEM and 95% CI NR
Green et al17ER, in abduction-active to P1SInclinometerSupineICC=.75ICC=.65SEM and 95% CI NR
Hayes et al18ER, passive to end ROMSVisualSittingICC2,1=.67, SEM=11°, 95% CI, ±22°ICC2,1=.57, SEM=14°, 95% CI, ±28°Not reliable
Hayes et al18ER active to end ROMSGoniometerSittingICC2,1=.65, SEM=14°, 95% CI, ±28°ICC2,1=.57, SEM=14°, 95% CI, ±28°Not reliable
de Winter et al35ER, passive‡SElectronic inclinometerSupine ICC=.90 (affected side), ICC=.56 (CL side)Changes in ROM <20°−25° = possible ME
Riddle et al13IR, passive⁎SShort goniometerVariableICC1,1=.93ICC1,1=.43SEM and 95% CI NR
Riddle et al13IR, passive⁎SLong goniometerVariableICC1,1=.94ICC1,1=.55SEM and 95% CI NR
Green et al17IR, in abduction-active to P1SInclinometerSupineICC=.82ICC=.44SEM and 95% CI NR
Green et al17HBB to P1SVisualStandingICC=.84ICC=.73SEM and 95% CI NR
Hayes et al18HBB, active to end ROMSTape measureStandingICC2,1=.39, SEM=6cm, 95% CI, ±12cmICC2,1=.39, SEM=.6cm, 95%CI ±12cmNot reliable
Hayes et al18HBB, passive to endROMSTape measureSittingICC2,1=.14, SEM=2 SL, 95% CI, ±4 SLICC2,1=.26, SEM=.2 SL, 95%CI ±4 SLNot reliable
Edwards et al11HBB, preselected levelASVisualNot statedICC=.44, 1–2 SL error from actual levelICC=.21, 1–2 SL error from actual levelSEM and 95% CI NR

NOTE. Adapted from Lewis and Tennent.29 Reprinted with permission.

Abbreviations: AS, asymptomatic; CL, contralateral; ER, external rotation; HBB, hand behind back; IR, internal rotation; ME, measurement error; NR, not reported; P1, first point of pain; ROP, recorded on paper; S, symptomatic; SEM, standard error of measurement; SL, spinal level.

⁎ End of range or point of pain not stated.

† To first point of pain or point at which scapular rotation commences.

‡ To first point of pain or end of range.

The aim of this study was to estimate the intraobserver reliability of measuring the physiologic movements of shoulder flexion, abduction in the plane of the scapula, external rotation with the arm by the side, and internal rotation with the arm by the side, in a group of subjects without shoulder symptoms and in a group with symptoms.

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Methods 

Participants 

Two groups of subjects, with and without shoulder symptoms, gave informed consent prior to participation in this investigation. We recruited subjects with symptoms through the orthopedic and physical therapy outpatient department in the teaching hospital where the study was conducted. Subjects without symptoms were recruited through personal contact and public advertisements. Permission to conduct this study was granted by the local research ethics committee (Riverside Research Ethics Committee).

Inclusion and exclusion criteria 

An inability to fully communicate in English, younger than 18 years of age; allergies to taping products; cardiac, respiratory, kidney, or circulatory problems; systemic disease; diabetes; and, for female subjects, pregnancy or suspicion of pregnancy were exclusion criteria for both groups. For subjects without symptoms, additional exclusion criteria were: a history of fractures, and treatment or surgery to the lumbar, thoracic, cervical spine, and upper limbs. Inclusion criteria for this group were subjects without lumbar, thoracic, cervical, or shoulder, or upper-limb symptoms. Inclusion criteria for subjects with symptoms were: pain and/or restriction of movement arising from the area of the shoulder.

Procedure 

We measured the 4 physiologic movements of interest on 2 separate occasions, on both sides of all subjects. Random number tables were used to randomly allocate subjects to the side to be tested first. The investigator measured each movement of interest using the measurement procedures described below. The investigator verbally relayed the measurements to an assistant who recorded each set of measurements on an individualized data entry sheet. At all stages the investigator was blinded to data entry. The 4 physiologic movements were measured in a constant order during data collection: flexion, abduction, external rotation, and internal rotation. The 4 physiologic movements were measured in each data collection phase. An interval of approximately 30 minutes separated the 2 data collection phases for each subject. This 30-minute gap served to reduce examiner bias to ensure the investigator was unable to recall any earlier measurements. In addition to this, and to further reduce bias, during this 30-minute interval, a set of measurements was made on a different subject. The data collection process was arranged as follows: subject 1 (first data collection phase), subject 2 (first data collection phase), subject 1 (second data collection phase), subject 2 (second data collection phase), etc. The examiner has had approximately 20 years of clinical experience and works as a consultant physical therapist for the National Health Service in the United Kingdom. As part of this role, the examiner works in an orthopedic outpatient department and independently assesses patients, requests investigations including radiographs, magnetic resonance imaging, and computed axial tomography scans, bone scans, blood tests, nerve conduction tests, and performs diagnostic and therapeutic injections and refers to other services.

Measurements 

We measured 4 physiologic movements in standing position. Prior to each set of measurements, subjects were asked to adopt a comfortable and natural standing position. To facilitate this, each subject was informed that during the investigation it was important that a natural posture should be adopted. Subjects were asked to gently flex and extend their head and stop in a position that felt natural and comfortable, to gently flex and extend their shoulders and stop in a position that felt natural and comfortable, and then finally to take a breath and adopt a posture that felt natural and comfortable.

We performed shoulder flexion in the sagittal plane. Subjects without symptoms were requested to perform the movement, leading with their thumb, to the end of their available range. Subjects with symptoms were requested to elevate to the first increase of pain, or if there was no pain, to the end of their available range. ROM was measured using an inclinometer.a The device was positioned just distal to the insertion of the deltoid muscle, with the base of the inclinometer placed parallel to the length of the humerus along its uppermost aspect. The subject performed the movement 3 times and the mean of the 3 measurements was used in the data analysis. The same procedure was used to measure shoulder abduction. Shoulder abduction was performed in approximately 45° off the sagittal and frontal planes. Shoulder external rotation was measured by asking the subject to keep the elbow by the side of the body and flexed to 90° with the forearm and palm facing upward. The subject was then requested to externally rotate the shoulder to the end of range (asymptomatic subjects) or to the first increase in pain, or the end of range if no pain was experienced (symptomatic subjects). External rotation range was measured in centimeters using a nonstretch fiberglass tape measure from the ulnar styloid process to the umbilicus. Three measurements were recorded and again the mean of the 3 was used in data analysis. Shoulder internal rotation was measured using the method suggested by Kessel12 and Kumar and Satku.9 The starting position was arm by the side with the thumb facing laterally. An imaginary line, transecting the medial and lateral humeral epicondyles in this position which was initially aligned in the frontal plane was considered as the starting position. It is acknowledged that this starting position is not the true neutral position of the shoulder, but this starting position was chosen to ensure a standardized method for the measurement of shoulder internal rotation. Subjects were requested to keep the arm by the side and internally rotate the shoulder to the first point of pain or end of range if there was no pain (symptomatic subjects), or to the end of range (asymptomatic subjects). The range of internal rotation was measured visually (without use of a goniometer) in 5° increments, as a function of the angle made from the starting position (imaginary line transecting the medial and lateral humeral epicondyles) in the frontal plane, to the angle made by the line at the end point of movement.

Power Analysis 

This study formed part of a series of studies aiming to investigate measurement reliability as well as relationships of posture for the shoulder and upper body. Walter et al30 have provided estimates to calculate the number of subjects needed for a reliability study where reliability is measured using intraclass correlation ρ. For a true ρ0 of .7 against an alternative ρ1 of .9, based on a 5% significance level and a power of 80% (β=20) for 2 raters, or 2 time points, 19 subjects are required.25, 30 Forty-five subjects were recruited into each group (total, n=90). This number of subjects was considered adequate to determine the intraobserver reliability for measuring the 4 physiologic measurements of interest in this study. Of interest, 46 subjects are the required number for a true ρ0 of .8 against an alternative ρ1 of .9.30

Statistical Analysis 

The descriptive statistics, and ICC model 3,1, 95% CI, and the SE of measurement statistics were analyzed using SPSSb software.

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Results 

We recruited forty-five subjects into each group. There were 24 (53%) women and 21 (47%) men in the asymptomatic group. There were 23 (51%) women and 22 (49%) men with symptoms. The shoulder diagnostic categories included: rotator cuff tendinopathy (n=12), frozen shoulder (n=2), stable clavicular fractures (n=4), glenohumeral instability (n=2), nonspecific shoulder pain (n=21), acromioclavicular joint pain (n=2), stable humeral fractures (n=1), and stable scapular fractures (n=1). The majority of subjects had experienced their symptoms for more than 3 months at the time of data collection. Descriptive information relating to these 2 subject groups is detailed in Table 2, Table 3.

Table 2. Subject Descriptive Data
SubjectsMean ± SDMinimumMaximum
Asymptomatic
Age (y)32±7.32356
Height (cm)173±9.1158191
Weight (kg)70±14.250111
Body mass index (kg/m2)23.3±3.717.533.5
Symptomatic
Age (y)42±16.61984
Height (cm)171±9.4149190
Weight (kg)71±11.84990
Body mass index (kg/m2)24.3±3.318.431.9
Table 3. Data Relating to Hand Dominance and Symptoms
ValuesAsymptomaticSymptomatic
LeftRightLeftRight
Hand dominance8(18)37(82)7(16)38(84)
Painful sideNANA18(40)27(60)

NOTE. Values are n (%).

Abbreviation: NA, not applicable.

The ICC, 95% CI, and SE of measurement data are presented in table 4 (subjects without symptoms) and table 5 (subjects with symptoms).

Table 4. Asymptomatic Subjects
MeasurementROM⁎Single Measure (ICC3,1)95% CISE of Measurement
Flexion (right shoulder) (deg)169±10.1(136–92).94.89–.972.5
Flexion (left shoulder) (deg)166±9.9(134–181).91.84–.952.8
Abduction (right shoulder) (deg)167±9.4(137–185).93.88–.962.4
Abduction (left shoulder) (deg)165±9.5(132–182).91.85–.952.7
Internal rotation (right shoulder) (deg)95±8.4(60–115).92.87–.962.4
Internal rotation (left shoulder) (deg)95±10.4(45–120).96.93–.982.1
External rotation (right shoulder) (cm)37.7±4.3(26.5–45.5).85.74–.911.6
External rotation (left shoulder) (cm)37.2±4.1(29.0–46.8).92.84–.961.1

⁎ Values are mean ± SD and range.

Table 5. Symptomatic Subjects
MeasurementROM⁎Single Measure (ICC3,1)95% CISE of Measurement
Flexion (painful shoulder) (deg)143±35.7(54–180).82.69–.8913.8
Flexion (nonpainful shoulder) (deg)167±10.7(133–186).89.82–.943.9
Abduction (painful shoulder) (deg)138±34.0(60–180).98.96–.994.8
Abduction (nonpainful shoulder) (deg)165±10.6(136–185).88.79–.933.6
Internal rotation (painful shoulder) (deg)85±16.2(45–110).98.98–.992.3
Internal rotation (nonpainful shoulder) (deg)95±5.6(80–105).83.71–.912.3
External rotation (painful shoulder) (cm)35.1±4.8(23.2–47.5).93.87–.961.3
External rotation (nonpainful shoulder) (cm)37.6±4.8(24.5–43.9).87.76–.931.5

⁎ Values are mean ± SD and range.

Descriptive statistics for the measurement of shoulder internal rotation range in the subjects with and without symptoms are presented in table 6.

Table 6. Descriptive Statistics for Shoulder Internal Rotation Range
SubjectsMean ± SD (deg)Minimum (deg)Maximum (deg)Mode (deg)
Asymptomatic (n=45)
Left shoulder
First measurement95±10.44512090(n=14)
Second measurement95±10.44512090(n=15)
Right shoulder
First measurement94±8.56011590(n=19)
Second measurement94±8.36511590(n=15)
Symptomatic (n=45)
Left shoulder
First measurement92±9.94511090(n=13)
Second measurement92±9.65011090(n=19)
Right shoulder
First measurement88±14.74510590(n=13)
Second measurement88±14.74511090(n=13)
Nonpainful shoulder
First measurement93±5.68510590(n=14)
Second measurement93±5.68010590(n=16)
Painful shoulder
First measurement87±16.34511090(n=13)
Second measurement87±16.14511090(n=15)

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Discussion 

Portney and Watkins26 have recommended that single measure ICC results above .91 are an acceptable level of reliability for clinical measurements. The measurement of external rotation for the right shoulder in the asymptomatic group did not achieve this level of reliability. In the symptomatic group, the following measurements did not achieve this level of reliability: flexion (painful shoulder), flexion (nonpainful shoulder), abduction (nonpainful shoulder), internal rotation (nonpainful shoulder), and external rotation (nonpainful shoulder). The lowest single measure ICC3,1 result was for painful shoulder flexion in the symptomatic group (.82); this was associated with an SE of measurement of 13.8°. When this result was reanalyzed with the outliers removed, the ICC result improved to .97 (95% CI, .94−.98), with an associated SE of measurement of 5.4°.

For ROM, clinicians require the ability to determine if any change in ROM associated with intervention is real. The SE of measurement is a statistic that informs the clinician about measurement error expressed in the unit of measurement of interest. The SE of measurement results reported in Table 4, Table 5 provide information that suggests that any change in the ROM less than or equal to the SE of measurement figure should only be considered as occurring in association with measurement error. Increases or decreases in the ROM of more than the SE of measurement value may be considered as being associated with real (positive or negative) change.

The measurements of shoulder flexion and abduction in the plane of the scapula range are recommended in most shoulder assessment protocols. These movements have also been investigated in studies that have investigated the relationship between upper-body posture and shoulder ROM.5, 6 The results of the current investigation suggest that the SE of measurement for these movements for both the left and right shoulders of subjects without symptoms ranges from 2.4° to 2.8°. This information, together with the single measure ICC and 95% CI results, may be of value for the clinician who wants to perform screening examinations on asymptomatic subjects, or for researchers who wish to investigate the effect of an intervention on asymptomatic subjects, or possibly establish the relationship between posture and movement, or establish what changes occur to shoulder flexion and abduction range in a longitudinal study in this group. The SE of measurement results for shoulder flexion and abduction in the group of subjects with shoulder symptoms ranged from 3.9° to 13.8°. When the outliers were removed from the symptomatic subjects, the largest SE of measurement was 5.4°. It is uncertain why the range for painful shoulder flexion (which in 60% of subjects was the right shoulder) should be associated with the highest SE of measurement. Potentially it would have been easier to explain this if the same finding had been reported also for shoulder abduction range in the plane of the scapula, because the findings might have been attributed to general uncertainty as to where the subjective interpretation of the first point of pain was occurring or potentially to a fatigue effect. If both ranges were affected in the same way, then the variation might also have been attributed to variation in pain perception over time. The movements of shoulder flexion and abduction involve variations and differences in muscle activity as well as the biomechanical relationships between the bony, musculotendinous, and capsular ligamentous structures of the shoulder. The biomechanical variations and differences between shoulder flexion and abduction may have accounted for the poor ICC results and larger SE of measurement for painful side flexion in subjects with shoulder symptoms. It is not possible to offer a definitive explanation; future research may be able to explain the reason why painful side shoulder flexion range in the symptomatic groups was associated with the lowest levels of reliability. The difference in means between the first and second measurements for painful shoulder flexion in the symptomatic group for the 3 outlier results was 63.6° (subject 4: first measurement, 113°; second measurement, 155°; subject 10: first measurement, 76°; second measurement, 120°; subject 17: first measurement, 56°; second measurement, 161°).

Although the reason for the poorer ICC result and the relatively large SE of measurement findings for painful shoulder flexion in this group remains undeterminable from the available results, an analysis of the first and second flexion measurements using a paired sample t test suggested that there was no significant difference for the measurement of painful side flexion (2-tailed, P=.26), which suggests that the second set of measurements was not significantly greater or smaller than the first. Fatigue was not considered to be the reason for the difference between the first and second measurements, as the second measurement was consistently higher than the first for the 3 subjects. It was speculated that the difference might have occurred due to an alteration in the perception of pain, due to the repeated movements of the shoulder during the data collection, which led to an alteration in the recorded ROM.

The range of shoulder external rotation is usually expressed in degrees. The technique used in this study involved measuring external rotation as the distance from the umbilicus to the ulnar styloid process. The maximum SE of measurement associated with this measurement for subjects with and without symptoms was 1.6cm. Clinically this finding suggests that for subjects with unilateral symptoms, a baseline measurement may be made with the unaffected shoulder and then compared to the side with symptoms. A side-to-side percentage comparison may be produced by dividing the distance on the symptomatic side by the distance on the asymptomatic side and multiplying this by 100. In addition to this, changes in this linear measurement of more than 1.6cm suggest that either an increase or decrease in shoulder external rotation range has occurred. Changes in range of less than this amount should only be considered as measurement error. Subjects who increase or decrease weight and the circumference of their waist during the time that measurements are being taken using this method would substantially reduce the accuracy of this method and potentially invalidate any change. However, a side-to-side linear and percentage comparison may be made at any time point. The accuracy of this technique would be compromised in subjects who were unable to fully supinate their forearms. To compensate for a lack of forearm supination, this measurement could be assessed with the thumb facing superiorly on both sides. The reliability of this modified technique would need verification in future research. Measuring essentially angular movement linearly, using tape measures, has been recommended in previous studies and clinical procedures involving lumbar, thoracic, and cervical spine movement7, 31, 32 and therefore should be considered as an alternative method of quantifying movement available at the shoulder. The presence of severe pain and movement restriction will generally make it impossible to measure shoulder external rotation range at 90° of shoulder abduction. As such, the ability to reliably measure shoulder external rotation with the arm by the side is one advantage of the method proposed in this study.

Clinically, shoulder internal rotation is not measured with the elbows flexed because the abdomen will potentially limit the available ROM. As a result of this limitation, the measurement of hand behind back has become a clinical measurement that is used to inform clinicians on the range of shoulder internal rotation. Hand behind back is an important movement to assess due to its functional importance in ADLs and it is commonly limited in patients with shoulder symptoms. However, it should not be considered as a measurement of shoulder internal rotation and issues pertaining to the reliability and validity of the measurement exist.11, 18 The recommendations suggested by Kessel12 and Kumar and Satku9 are appealing because they allow for the measurement of shoulder internal rotation to be made with the arm by the side, which is potentially a position that is less pain provocative for many patients than measuring shoulder internal rotation range with the shoulder abducted to 90°. The minimum and maximum ranges, mean, SD, and mode values for measuring internal rotation in this manner in this investigation are detailed in table 6. Williams et al33 have stated that during shoulder rotation the humerus revolves about one quarter of a circle about a vertical axis. The range of rotation is therefore approximately 90° and the findings of the current investigation support this, as the mode for all the measurements in both groups was 90°.

Although the ranges of internal rotation recorded in the current study varied from 45° to 120° for the subjects without symptoms and from 45° to 110° for the subjects with symptoms, the finding that the most frequent range measured visually was 90° may have influenced the reliability results. It is acknowledged that it is visually easier to determine a 90° change in range (being at a right angle) from the baseline than any other another angle using visual estimation. As such the reliability results may have been influenced by the homogeneity of the results with regard to the large number of subjects who were found to have an internal rotation range close to 90° from the baseline angle. Further research is required to investigate the reliability as well as the validity of this method of measuring shoulder internal rotation.

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Conclusions 

Shoulder ROM is frequently limited by pain and joint restriction in subjects with shoulder symptoms. In subjects without shoulder symptoms, there is uncertainty regarding the relationship of shoulder ROM and posture, as well as uncertainty relating to any longitudinal influences on shoulder ROM. The results of this intrarater reliability study suggest that for 1 observer employing the methods and procedures applied in this investigation the majority of the main physiologic movements of the shoulder may be measured reliably for subjects both with and without shoulder symptoms. The methods described are relatively quick and inexpensive and do not require lengthy set up times, quiet environments, or expensive equipment. For clinicians involved in the management of subjects with shoulder symptoms the SE of measurement results provide guidance as to the error associated with the individual measurements. Using the SE of measurement results, the clinician may determine if a clinically important change, be it negative or positive, has occurred as a result of any intervention offered. Of note, the SE of measurement values for the range of shoulder flexion in subjects with symptoms, as well as for the range of flexion in the symptomatic shoulder, are associated with a larger SE of measurement than the other physiologic movements. This needs to be considered when attempting to determine if a clinically important change has occurred when measuring these particular movements. Further research is required to determine the interobserver reliability as well as to establish the reliability of measuring other shoulder ROMs.

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Acknowledgment 

We acknowledge the support of the physiotherapy outpatient staff at Chelsea and Westminster Hospital.

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  • a Isomed Inc, 975 SE Sandy Blvd, Portland, OR 97214.
  • b Version 14; SPSS Inc, 233 S Wacker Dr, 11th Fl, Chicago, IL 60606.

 Supported by the Westminster Medical School Research Trust and the Chelsea and Westminster Healthcare NHS Trust Charity.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 author(s) or upon any organization with which the author(s) is/are associated.

PII: S0003-9993(06)00439-4

doi:10.1016/j.apmr.2006.05.008

Archives of Physical Medicine and Rehabilitation
Volume 87, Issue 9 , Pages 1242-1249, September 2006

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