**9. Proprioception in shoulder instability**

The AAR has been used to assess shoulder proprioception before, for example, in shoulder instability. Pötzl and colleagues examined the proprioceptive capabilities of 14 patients with recurrent anterior shoulder instability preoperatively and at least five years postoperatively using the AAR test [20]. In their series the joint position sense improved significantly in abduction, flexion, and rotation (p<0.05). They concluded that five years after surgical restoration of shoulder instability the joint position sense improved significantly to the same level as normal healthy shoulders. Having these results in mind we have to ask why proprioception measured with a comparable AAR deteriorates after shoulder arthroplasty, whereas it improves after surgery of shoulder instability?
