How to Assess Shoulder Functionality: A Systematic Review of Existing Validated Outcome Measures

Test-retest reliability of isometric shoulder muscle strength during abduction and rotation tasks measured using the Biodex dynamometer

BACKGROUND

The Constant score (CS) is often used clinically to assess shoulder function and includes a muscle strength assessment only for abduction. The aim of this study was to evaluate the test-retest reliability of isometric shoulder muscle strength during various positions of abduction and rotation with the Biodex dynamometer and to determine their correlation with the strength assessment of the CS.

METHODS

Ten young healthy subjects participated in this study. Isometric shoulder muscle strength was measured during 3 repetitions for abduction at 10° and 30° abduction in the scapular plane (with extended elbow and hand in neutral position) and for internal and external rotation (with the arm at 15° abduction in the scapular plane and elbow flexed at 90°). Muscle strength tests with the Biodex dynamometer were measured in 2 different sessions. The CS was acquired only in the first session. Intraclass correlation coefficients (ICCs) with 95% confidence interval, limits of agreement, and paired t tests for repeated tests of each abduction and rotation task were calculated. Pearson's correlation between the strength parameter of the CS and isometric muscle strength was investigated.

RESULTS

Muscle strength did not differ between tests (P > .05) with good to very good reliabilities for abduction at 10° and 30°, external rotation and internal rotation (ICC >0.7 for all). A moderate correlation of the strength parameter of the CS with all isometric shoulder strength parameters was observed (r > 0.5 for all).

CONCLUSION

Shoulder muscle strength for abduction and rotation measured with the Biodex dynamometer are reproducible and correlate with the strength assessment of the CS. Therefore, these isometric muscle strength tests can be further employed to investigate the effect of different shoulder joint pathology on muscle strength. These measurements consider a more comprehensive functionality of the rotator cuff than the single strength evaluation in abduction within the CS as both abduction and rotation are assessed. Potentially, this would allow for a more precise differentiation between the various outcomes of rotator cuff tears.

Effectiveness of Exercises With Electromyographic Biofeedback in Conservative Treatment of Massive Rotator Cuff Tears: A Randomized Controlled Study

OBJECTIVE

The aim of the study is to investigate the effectiveness of a rehabilitation program with electromyographic biofeedback compared with the control group on patients with massive rotator cuff tear.

DESIGN

Forty-six adults with massive rotator cuff tears, randomly assigned to 2 groups (23 electromyographic biofeedback group vs. 23 control group). The electromyographic biofeedback group (experimental group) performed the exercises under the guidance of electromyographic biofeedback, unlike the control group. All patients underwent a 45-minute training session a day, 3 times a week over a 6-wk duration, and followed up until 1-year. The outcome measures were American Shoulder and Elbow score, shoulder flexion strength, shoulder range of motion, Numeric Pain Rating Scale, and Global Rating of Change Scale.

RESULTS

Compared with the control group, the electromyographic biofeedback group demonstrated a significant change in shoulder flexion strength and patient satisfaction from baseline to 6 wks (posttraining) and from baseline to 12-mo follow-up ( F = 4.671, P = 0.005). There were significant improvements in within groups statistics for American Shoulder and Elbow score, shoulder flexion strength, shoulder range of motion, and Numeric Pain Rating Scale in both groups ( P < 0.05).

CONCLUSIONS

The results demonstrate that deltoid-focused structured rehabilitation program combined with electromyographic biofeedback can be used to increase shoulder flexion strength and patient satisfaction in conservative treatment of massive rotator cuff tear.

Sonographic and elastographic findings after arthroscopic rotator cuff repair: a comparison with clinical results

OBJECTIVE

We assessed the relationship between early postoperative clinical outcomes of arthroscopic rotator cuff repair (ARCR) and observations obtained by postsurgical ultrasound (US) and strain elastography (SE) of repaired supraspinatus tendons (SSTs).

METHODS

This retrospective study included 42 cases in which the patient underwent ARCR followed by postoperative US and SE. The Korean Shoulder Scoring (KSS) system was used to assess preoperative and postoperative conditions. The thickness of the repaired SST and subdeltoid fluid was measured by US. SE scores were classified into four grades (1 to 4) according to elasticity of repaired SST. In addition, SE scores were divided into two groups: soft (SE scores of 1 and 2) and hard (SE scores of 3 and 4). The relationship between clinical outcomes and US parameters and SE scores was determined by KSS.

RESULTS

Postoperative SE scores observed by two readers correlated significantly with function (p = 0.021 and p = 0.021, respectively) and muscle strength (p = 0.008 and p = 0.015, respectively). SE scores were significantly correlated with a difference value of muscle strength of KSS scores (p = 0.002 and p = 0.014). In a comparison of hard and soft groups of repaired SSTs, function (p = 0.008 and p = 0.010, respectively) and muscle strength (p = 0.002 and p = 0.014, respectively) in postoperative KSS scores were statistically higher in the hard SE scores than the soft SE scores. The difference value of function (p = 0.021 and p = 0.021,) and muscle strength (p = 0.008 and p = 0.015) of KSS scores was significantly higher in the hard SE scores.

CONCLUSIONS

Postoperative SE scores of repaired tendons correlated significantly with muscle strength and function after ARCR. Postoperative US images including thickness of repaired tendon and subdeltoid fluid did not correlate with clinical outcome.

ADVANCES IN KNOWLEDGE

SE evaluations of repaired SST may provide important information about postoperative muscle strength and function.

Cross-cultural adaptation and validation of the Arabic version of the simple shoulder test in the United Arab Emirates

Background

The Simple Shoulder Test (SST) is a simple and short patient-reported outcome measuring functional limitations of the affected shoulder in patients with shoulder dysfunction. Although it is widely used in different clinical cultures, literature review to date revealed that the SST has not been yet translated nor validated in the Arabic language.

Research objectives

To translate, culturally adapt, and validate the Arabic version of the Simple Shoulder Test (SST).

Methodology

A forward-backward translation method was adopted. One hundred and forty-one patients with shoulder pain were recruited for psychometric analysis based on the inclusion criteria. The test–retest reliability of the Arabic SST (ASST), pain, disability and total scores were assessed using intraclass correlation coefficients (ICC). The construct validity of the ASST was tested by Spearman rank coefficients through comparing the Arabic SST scores to the severity of shoulder pain measured using the visual analogue scale (VAS) and the Arabic version of the Shoulder Pain and Disability Index (SPADI). Internal consistency was assessed by the Cronbach’s alpha.

Findings

One hundred and forty participants (60 males and 80 females) with a mean (Standard Deviation) age of 39.3 (4.9) years participated in the study. The ICCs for score of ASST were reported high; pain 0.84 (0.78–0.93), disability 0.96 (0.93–0.97) and total score 0.95 (0.91–0.97). Similarly, the Cronbach α values for the ASST scores were also of high values with regards to pain (0.89), disability (0.94), and total score (0.97) respectively. Comparing the scores between the first and the second use of the ASST revealed no statistically significant mean differences of -1.9 (95% CI—3.61 to 0.17).

Conclusion

The Arabic-translated version of the SST showed high reliability, internal consistency, and construct validity based on substantial correlations of the ASST with Arabic SPADI and VAS. We recommend the Arabic version of the SST for the evaluation of Arabic-speaking patients with shoulder dysfunction.