Incarcerated Sternoclavicular Joint Intra-articular Disc Following Closed Reduction of a Posterior Dislocation Leading to Recurrent Anterior Instability.

Traumatic posterior dislocations of the sternoclavicular joint (SCJ) are rare. One option for management is to undertake a closed reduction within 48 hours, confirmed by a post-reduction computed tomography (CT) scan. We describe the case of a 17-year-old male patient who sustained a posterior SCJ dislocation that was treated within 48 hours by a closed reduction confirmed by CT. However, he went on to develop recurrent SCJ instability. A magnetic resonance imaging (MRI) arthrogram demonstrated that the intra-articular disc had been incarcerated at the back of the joint at the time of reduction and tears to both the anterior and posterior capsule. He underwent a successful open excision of the disc and hamstring tendon autograft reconstruction. Following closed reduction for an acute posterior SCJ dislocation, we would recommend undertaking a post-reduction MRI scan to confirm the reduction and status of the soft tissues.