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.

In vivo measurements of glenohumeral distraction technique performed in three different joint positions.

Introduction: Distraction techniques are an important part of the manual approach in the glenohumeral joint; however, there is controversy regarding the initial joint position to maximize separation of joint surfaces.Objective: To identify, through an in vivo exploration, the behavior of the coracohumeral distance (CHD) during the application of a short lever arm grade III distraction technique on the humeral head, executed in three different glenohumeral positions (zero position (P0), rest position (RP) and 90º abduction position with maximum external rotation (ABD+ER)).Methods: 15 participants were selected. A physical therapist executed grade III distraction techniques in described joint positions. Ultrasound was used to visualize the differences in CHD. Statistical analysis included interclass correlation coefficients (ICC) and repeated measurements of ANOVA.Results: The range of ICC values was 0.740 and 0.948. The differences in CHD were 5.74 ± 0.51 mm, 3.97 ± 0.24 mm, and 0.64 ± 0.02 mm, for P0, RP and ABD+ER during application of distraction technique, respectively. There were differences between P0 and RP with ABD+ER (P < 0.001), and no differences between P0 and RP.Conclusion: Initial joint position of application influences the separation of the articular surfaces, being wider in the zero and rest positions.