Comparative analysis of acromiohumeral distances according to the locations of the arms and humeral rotation

Are acromiohumeral distance measurements on conventional radiographs reliable? A prospective study of inter-method agreement with ultrasonography, and assessment of observer variability

OBJECTIVES

This study aims to investigate the reliability of acromiohumeral distance (AHD) measurements using conventional radiographs and to compare non-standardized and standardized radiographs with intra-/interobserver reliability measurements.

PATIENTS AND METHODS

Between February 2021 and January 2022, a total of 110 shoulders of 55 patients (25 males, 30 females; mean age: 49.7±12.6 years; range, 25 to 77 years) were included. Radiographs were taken in four different positions: primarily shoulder anteroposterior (AP), true AP, standardized true AP, and standardized outlet views. The AHD was measured by three orthopedists. A prospective ultrasonography (US) evaluation was performed by an experienced physiatrist, and the relationship between US and radiographic measurements was evaluated. The intra- and interobserver reliability of radiographic measurements was assessed.

RESULTS

On the standardized true AP view measurements, all observers showed a moderate to good agreement with US measurements (intraclass correlation coefficients [ICC]: 0.68-0.75). There was no significant difference between the AHD measurements of the senior orthopedist on standardized true AP and outlet views, and the US measurements. The intraobserver agreement of US measurements was excellent (ICC: 0.98, 95% confidence interval [CI]: 0.98-0.99), and the intraobserver agreement level of measurements on radiographs were good to excellent with a wide range of ICC values (ICC: 0.79-0.97). Interobserver reliability was the highest on the standardized outlet view, with an ICC of 0.91 and 0.88 in two measurement times. Interobserver reliability of other measurements were good with ICC values ranging from 0.82 to 0.88.

CONCLUSION

The AHD measurements on radiographs are compatible with US measurements within up to 2 mm difference if standardization is ensured. Also, measurements on standardized views have a superior consistency with lower standard error of measurement and minimal detectable change values. Therefore, we recommend using standardized true shoulder AP and standardized outlet radiographs in clinical practice and studies, as these are the most accurate in demonstrating true AHD.

Shoulder kinematics impact subacromial proximities: a review of the literature

BACKGROUND

Alterations in glenohumeral and scapulothoracic kinematics have been theorized to contribute to rotator cuff pathology by impacting the magnitude of the subacromial space.

OBJECTIVE

The purpose of this review is to summarize what is currently known about the relationship between shoulder kinematics and subacromial proximities.

CONCLUSIONS

A variety of methods have been used to quantify subacromial proximities including photographs, MR imaging, ultrasonography, and single- and bi-plane radiographs. Changes in glenohumeral and scapulothoracic kinematics are associated with changes in subacromial proximities. However, the magnitude and direction of a particular motion's impact on subacromial proximities often vary between studies, which likely reflects different methodologies and subject populations. Glenohumeral elevation angle has been consistently found to impact subacromial proximities. Plane of humeral elevation also impacts subacromial proximities but to a lesser degree than the elevation angle. The impact of decreased scapulothoracic upward rotation on subacromial proximities is not absolute, but instead depends on the angle of humerothoracic elevation. The effects of scapular dyskinesis and humeral and scapular axial rotations on subacromial proximities are less clear. Future research is needed to further investigate the relationship between kinematics and subacromial proximities using more homogenous groups, determine the extent to which compression and other factors contribute to rotator cuff pathology, and develop accurate and reliable clinical measures of shoulder motion.

What is the reliability of clinical measurement tests for humeral head position? A systematic review

STUDY DESIGN

Systematic review.

INTRODUCTION

Physiotherapists routinely assess the position of the humeral head (HH) in patients with shoulder pain.

PURPOSE OF THE STUDY

To conduct a systematic review to determine the quality and content of studies that evaluated the reliability of clinical measurement methods for assessing the HH position.

METHODS

Five databases and gray literature were searched for studies fitting the eligibility criteria. After abstract and full-text review, the included studies were appraised using the Quality Appraisal of Reliability Studies checklist. Articles were considered of high quality if 8 was achieved on the checklist, and the overall quality of evidence was classified using prespecified criteria. Multiple raters extracted and performed quality ratings; a consensus process was used to finalize the reliability data that were synthesized and presented in a narrative synthesis. Reliability was classified as excellent if the intracorrelation coefficients or intercorrelation coefficients (ICCs) reported exceeded 0.75.

RESULTS

Fifteen studies on the reliability of ultrasound (US) and 3 studies on palpation were included. The methodologic quality was moderate in 17 of 18 studies. The intrarater reliability for all studies was excellent (ICC, 0.76-0.99) with the exception of the 90° abduction in internal rotation position (ICC, 0.48) for palpation. The inter-rater reliability tended to be lower (ICC, 0.48-0.68) for palpation and higher (ICC, 0.66-0.99) for US. Physiotherapists demonstrated excellent intrarater reliability across different levels of training in ultrasonography.

DISCUSSION

Our study found a moderate overall level of evidence to support the use of US for assessing HH position in symptomatic or asymptomatic subjects.

CONCLUSION

A moderate overall level of evidence exists for the use of US to reliably assess the HH position. Limited research supports the methods used for palpation within a clinical setting.

LEVEL OF EVIDENCE

2a.

The effect of exercise types for rotator cuff repair patients on activities of shoulder muscles and upper limb disability

[Purpose] This study investigated the effect on activities, shoulder muscle fatigue, upper limb disability of two exercise types performed by patients in the post- immobilization period of rotator cuff repair. [Subjects and Methods] The intervention program was performed by 20 patients from 6 weeks after rotator cuff repair. Ten subjects each were randomly allocated to a group performing open kinetic chain exercise and a group preforming closed kinetic chain exercise. Muscle activity and median frequency were measured by using sEMG and the Upper Extremity Function Assessment before and after conducting the intervention and changes in the results were compared. [Results] There was a significant within group increases in the activities of the shoulder muscles, except for the posterior deltoid. The median power frequencies (MFD) of the supraspinatus, infraspinatus and anterior deltoid significantly increased in the open kinetic chain exercise group, but that of the posterior deltoid decreased. There were significant differences in the changes in the upper limb disability scores of the two groups, in the shoulder muscle activities, except for that of the posterior deltoid, in the comparison of the change in the muscle activities of the two groups, and in the MDFs of all shoulder muscles. [Conclusion] The Median power frequencies of all these muscles after closed kinetic chain exercise increased indicating that muscle fatigue decreased. Therefore, research into exercise programs using closed kinetic chain exercises will be needed to establish exercise methods for reducing muscle fatigue.