Instability of the sternoclavicular joint is most often anterior, but can be superior, and is either developmental in teen-agers or post-traumatic. Symptomatic cases have painful dislocations of the medial clavicle end when the arm is in abduction, extension, and outward rotation. The effect of non-surgical treatment is undocumented. Surgery is based on stabilization of the joint with a tendon graft (usually gracilis or semitendinosus). We prefer a technique by which the intra-articular disc is spared, which is also appropriate in young persons with an active epiphysis. The tendon is fixed to sternum in a drill tunnel and the clavicle is stabilized by a V-shaped reconstruction through two drill tunnels in the clavicle. The risk of re-instability after the procedure is about 15%.