Biomechanics of posterior shoulder instability - current knowledge and literature review

Figure 1 Jerk test and Kim test. A: Jerk test: The patient is sitting, their arm is flexed to 90° and internally rotated. An axial loading and horizontal adduction is applied; B: Kim test: The patient is sitting and the arm is abducted to 90° at the beginning. The examiner elevates the arm approximately 45° while applying postero-inferior force to the upper arm and axial load to the elbow. In a positive test, a subluxation of the glenohumeral joint can be observed.

Figure 2 Posterior labral tear. A: Posterior labral tear in magnetic resonance arthrography; B: Intraoperative finding of a posterior labral tear and posterior SLAP tear.