Reliability of a new standardized measurement technique for reverse Hill-Sachs lesions in posterior shoulder dislocations

Abstract

Purpose: The purpose of this study was to determine whether standardized measurements are more reliable than mere estimation in determining the extent of the defect in reverse Hill-Sachs lesions.

Methods: Twelve patients with 13 reverse Hill-Sachs lesions and available computed tomographic scans were included in this study. Based on the computed tomographic scans, estimation and measurement of the defect size in reverse Hill-Sachs lesions using a novel standardized method were carried out twice by 6 observers (3 experts and 3 residents), with an interval of 3 months between observations. To assess and compare the reliability of the estimation of the defect size and the measurement of the defect size, intraclass correlation coefficients were computed.

Results: Estimation of the defect size showed a low interobserver reliability of 0.61 (95% confidence interval [CI], 0.38 to 0.83) and 0.47 (95% CI, 0.24 to 0.74) and a moderate intraobserver reliability of 0.71 (95% CI, 0.51 to 0.89). The estimations of the different observers showed statistically significant differences (P < .001). The standardized measurements reached high interobserver reliability (at least ≥0.81) and excellent intraobserver reliability (at least ≥0.88). Residents provided less reliable estimations compared with experts; however, they obtained similarly high reliability when applying the standardized measurements.

Conclusions: The mere estimation of the size of reverse Hill-Sachs lesions showed poor reliability, raising the concern for potential overestimation or underestimation in clinical practice. Standardized measurements, which showed good reliability, should be used whenever analyzing the size of a reverse Hill-Sachs defect.

Level of evidence: Level IV, diagnostic case series.