Shoulder instability Assessment of anterior-posterior translation with a knee laxity tester

Abstract

We developed a simple method to measure the anterior-posterior (AP) translation of the shoulder joint: by positioning the Donjoy® Knee Laxity Tester horizontally over the shoulder girdle, the AP translation was measured after applying a standardized sagittal force. Measurement of AP-translation during two tests on the same shoulder was reproducible with an intraclass correlation coefficient (ICC) of 0.996. In normal subjects the mean side difference was 0.6 mm, corresponding to a p-value of 1.00. In patients with unilateral instability AP-translation was significantly larger on the injured shoulder. Furthermore, the intraindividual differences in AP-translation were significantly larger in patients with unilateral instability than in normal subjects. Individuals with multidirectional instability had significantly higher values than any of the other groups.