A 12-year old female miniature Poodle was presented because of a 4/4 right fore-limb lameness. The orthopedic examination demonstrated pain at palpation of the right shoulder and an abduction angle of 55 °. MRI examination confirmed injuries consistent with a traumatic medial shoulder instability with no evidence of shoulder dysplasia. A partial rupture of the subscapularis tendon and complete detachment of the cranial gleno- humeral ligament were confirmed with arthroscopy. The joint was successfully stabilized using an arthroscopic assisted prosthetic suture.