In vivo effects of two shoulder girdle motor control exercises on acromiohumeral and coracohumeral distances in healthy men

Intra- and inter-rater reliability in ultrasonographic measurements of coracohumeral distance

BACKGROUND

Ultrasonography (US) is a widely used diagnostic tool in physical therapy. One of the US variables often utilized to quantify the dimensions of the subacromial space and its association with shoulder pathology is the coracohumeral distance (CHD), however, this measurement presents diverse evidence in terms of reliability.

OBJECTIVES

To assess the intra- and inter-rater reliability of both expert and non-expert raters when measuring CHD through US in asymptomatic subjects. Additionally, we determined the effect of rater experience and measurement conditions on the recording of CHD.

METHODS

CHD of 15 individuals were recorded from US images of the glenohumeral joint of both upper extremities in three different positions. An expert and a non-expert rater in US usage recorded three CHD measurements, after a randomization procedure. To determine intra- and inter-rater reliability, the interclass correlation coefficient (ICC) and a multivariate variance model for the effects of rater experience, joint position and time of measure were used. Standard Error of Measurement and Minimal Detectable Change was also estimated for CHD measurements.

RESULTS

Intra-rater reliability ranged 0.970 to 0.998) and Inter-rater reliability ranged 0.48 to 0.876). Joint position (F2;55 = 38.308; p < 0.001; ηp2 = 0.582) and measurement time (F2;55 = 6.019; p = 0.004; ηp2 = 0.180) effect was observed on CHD.

CONCLUSION

Excellent intra- and poor to moderate inter-rater reliability between expert and non-expert clinicians was determined, the latter being influenced by the position of the glenohumeral joint position at the time of US recording and the time of recording the measurement.

Reliability of coracohumeral distance and subcoracoid tendons in subacromial pain syndrome

This study investigated the intra-rater reliability of a novice ultrasound (US) examiner and the inter-rater reliability of two examiners (novice, expert) in the measures of coracohumeral distance at rest (CHD) and at 60° of elevation without (CHD60) or with weights (CHD60w), tendon thickness of the long head of the biceps (LHB) and subscapularis (SCP). Twenty-one patients with subacromial pain syndrome (SAPS) and 20 asymptomatic participants were included. Intra and inter-rater reliability were tested with intraclass-correlation-coefficient (ICC), differences between raters were analyzed with Bland-Altman plots. Intra-rater reliability for CHD, CHD60 and CHD60w was excellent (ICC = 0.97-0.98) in asymptomatic participants, and good-to-excellent (0.88-0.93) in SAPS, while intra-rater reliability for LHB and SCP was good-to-excellent in asymptomatic participants (0.88-0.97) and in SAPS (0.90-0.92). Inter-rater reliability for CHD, CHD60 and CHD60w was moderate-to-good (0.70-0.90) in asymptomatic participants and good (0.85-0.87) in SAPS, in contrast inter-rater reliability for LHB and SCP was poor in asymptomatic participants (0.10-0.46) and poor-to-moderate (0.49-0.61) in SAPS. Bland-Altman plots revealed systematic and/or proportional bias for tendons' thickness. A novice showed good-to-excellent intra-rater reliability in all US measures, whereas in comparison to an expert a novice can measure reliably CHD, CHD60 and CHD60w, but not LHB and SCP, where more training is recommended.