The sternoclavicular joint (SCJ) is a pivotal articulation in the linked system of the upper limb girdle, providing load-bearing in compression while resisting displacement in tension or distraction at the manubrium sterni. The SCJ and acromioclavicular joint (ACJ) both have a small surface area of contact protected by an intra-articular fibrocartilaginous disc and are supported by strong extrinsic and intrinsic capsular ligaments. The function of load-sharing in the upper limb by bulky periscapular and thoracobrachial muscles is extremely important to the longevity of both joints. Ligamentous and capsular laxity changes with age, exposing both joints to greater strain, which may explain the rising incidence of arthritis in both with age. The incidence of arthritis in the SCJ is less than that in the ACJ, suggesting that the extrinsic ligaments of the SCJ provide greater stability than the coracoclavicular ligaments of the ACJ. Instability of the SCJ is rare and can be difficult to distinguish from medial clavicular physeal or metaphyseal fracture-separation: cross-sectional imaging is often required. The distinction is important because the treatment options and outcomes of treatment are dissimilar, whereas the treatment and outcomes of ACJ separation and fracture of the lateral clavicle can be similar. Proper recognition and treatment of traumatic instability is vital as these injuries may be life-threatening. Instability of the SCJ does not always require surgical intervention. An accurate diagnosis is required before surgery can be considered, and we recommend the use of the Stanmore instability triangle. Most poor outcomes result from a failure to recognise the underlying pathology. There is a natural reluctance for orthopaedic surgeons to operate in this area owing to unfamiliarity with, and the close proximity of, the related vascular structures, but the interposed sternohyoid and sternothyroid muscles are rarely injured and provide a clear boundary to the medial retroclavicular space, as well as an anatomical barrier to unsafe intervention. This review presents current concepts of instability of the SCJ, describes the relevant surgical anatomy, provides a framework for diagnosis and management, including physiotherapy, and discusses the technical challenges of operative intervention. Cite this article: Bone Joint J 2013;95-B:721–31

After establishing anatomical feasibility, functional reconstruction to replace the anterolateral part of the deltoid was performed in 20 consecutive patients with irreversible deltoid paralysis using the sternoclavicular portion of the pectoralis major muscle. The indication for reconstruction was deltoid deficiency combined with massive rotator cuff tear in 11 patients, brachial plexus palsy in seven, and an isolated axillary nerve lesion in two. All patients were followed clinically and radiologically for a mean of 70 months (24 to 125). The mean gender-adjusted Constant score increased from 28% (15% to 54%) to 51% (19% to 83%). Forward elevation improved by a mean of 37°, abduction by 30° and external rotation by 9°.

The pectoralis inverse plasty may be used as a salvage procedure in irreversible deltoid deficiency, providing subjectively satisfying results. Active forward elevation and abduction can be significantly improved.

We describe a new method of stabilising a painful unstable sternoclavicular joint using the sternocleidomastoid tendon and passing it through the medial clavicle and onto the manubrium sternum. This method is simple, reproducible and avoids the potential risks of reefing the joint to the first rib. The technique was used in seven cases of sternoclavicular joint instability in six patients who were reviewed at a mean of 39.7 months (15 to 63). Instability was markedly reduced or eliminated in all cases, but in one there was occasional persistant subluxation. There were minor scar complications after two procedures and one patient had transient ulnar neuritis. This procedure provides satisfactory results in the medium term