|Beitragstitel||Inter- and Intra-observer variability of Glenoid Track measurements|
Recently a method of assessing combined glenoid and humeral bone loss in traumatic shoulder instability with an associated treatment protocol was published (Di Giacomo et al). The aim of this study was to investigate its reliability and reproducibility.
71 patients with unilateral antero-inferior shoulder instability underwent CT scans, from which 3D images were derived. En-face views of both glenoid fossae, along with 3 views of the humeral head were provided to 4 assessors to determine inter-observer reliability. From these measurements the shoulder was assigned a treatment classification. Two ob-servers repeated their assessments a month later to determine intra-observer reliability. For each measurement, the mean Co-efficient of Variability (CoV) was calculated.
Assessment of glenoid bone loss showed good inter-observer (4 observers agreeing in 90.1% of cases) and also a good intra-observer agreement (94% and 96%).
There was a poor level of inter-observer reliability regarding On- or Off-track classification (72%). Intra-observer reliability for this measurement was less variable (90% and 80%).
There was a poor level of agreement between observers (65%) regarding treatment classi-fication.
The CoV for the Hill-Sachs lesion measured 19.2%, indicating a high level of variability for this measurement, compared with < 4% for all other measures.
Linear bone loss on the glenoid can be measured reliably and reproducibly, however eva-luation of Hill-Sachs lesions demonstrates a high level of variability, and poor inter-observer reliability.