Sternoclavicular Joint Pain and Instability

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This article reviews sternoclavicular instability and pain. See Sternoclavicular Joint for a review of the anatomy. The sternoclavicular joint (SCJ) is inherently unstable. The main stabilisers are the strong extrinsic ligaments, and to a lesser extent the muscular envelope.

Classification of Instability

SCJ instability can be structure or non-structural, and causative factors may be traumatic, atraumatic, neurological, or a combination. Other than an acute first time event, instability may be persistent or recurrent. Dislocations are usually anterior, but can uncommonly be posterior.

Stanmore's triangle system, traditionally used for describing glenohumeral joint instability, has also been used to describe SCJ instability. There are three factors that are represented as points in a triangle: type I traumatic structural, type II atraumatic structure, and type III muscle patterning (neuromuscular) non-structural. The groups exist as a spectrum, and patients can have features of two groups, and/or move to a different pattern. With type I, there is a history of trauma such as SCJ dislocation or medial clavicular fracture. In Type II there is a structural capsular pathology without a history of "macro"-trauma but there may be micro-traumatic change. In type III there is a pathological muscle-pattern with inappropriate activation of the pectoralis major clavicular and sternal parts. This is most noticeable with eccentric overhead activities. Muscle patterning can be difficult to detect.

The spectrum of pathologies affecting the SCJ can be categorised into the three Stanmore instability groups. For type I traumatic structural there is medial clavicular fracture and dislocations (posterior, anterior). For type II atraumatic structural there are the heritable connective tissue disorders causing capsular laxity (e.g. Ehlers Danlos syndrome, Marfan syndrome), short clavicular shape increasing torque on the SCJ, osteoarthritis, inflammatory arthritis, infection, and sternoclavicular hyperostosis syndrome. For type III non-structural there is pathological activation of pectoralis major.

Characteristics of the Stanmore triangle classification of joint instability

Pathology	Type I: Traumatic structural	Type II: Atraumatic structural	Type III: Muscle patterning, non-structural
Trauma	Yes	No	No
Articular surface damage	Yes (e.g. disc or chondral injuries)	Not initially, but occurs when longstanding (disc attrition)	No
Capsular problem	Yes	Yes	Sometimes
Laxity	Unilateral	Uni-/bilateral	Often bilateral
Muscle patterning	Normal	Normal	Abnormal pectoralis major activity
Treatment	Physiotherapy + often ORIF, SCJ reconstruction	Physiotherapy +/- SCJ reconstruction	Physiotherapy (biofeedback)

Clinical Assessment

Red Flags

• High energy injury (concomitant injuries)
• Stridor, dysphagia, shortness of breath (oesophageal or tracheal compression)
• Venous congestion of the face and upper limb (subclavian vein compression)
• Unequal pulses (subclavian artery compression)
• Subtle findings (posterior dislocation)
• Child (medial clavicular physeal or metaphyseal fracture-separation)

Medial clavicular fractures and first-time traumatic SCJ dislocations are caused by direct or indirect injury. Posterior dislocation of the SCJ (referring to the medial clavicle dislocating posteriorly) can be sustained by a direct blow tot he anteromedial aspect of the clavicle. Anterior displacement tends to occur through a characteristic oblique shearing extracapsular fracture in the medial clavicle (disrupting the anterior capsule +/- coraco-clavicular ligament (CCL), while sparing the posterior capsule), and can be sustained by a compressive force applied to the lateral aspect of the shoulder girdle such as when being struck from the side. With these high-energy injuries there should be a high index of suspicion for additional internal thoracic and upper limb injuries. This type of force can also cause anterior dislocation, and can be difficult to differentiate from a medial clavicular fracture. A fractured medial clavicle has a blunt pointed shape and moves obliquely in front of the sternum, while with a dislocated SCJ the medial clavicle moves forward (not across the sternum) and looks like a lump. A compressive lateral force with the arm flexed at the shoulder is another mechanism for posterior SCJ dislocation.

Anterior dislocations are generally quite obvious presenting as a prominent anterior lump. Posterior dislocations on the other hand are often subtle. Pain and swelling are often localised to the joint. The patient may hold their arm across their chest to minimise both glenohumeral and scapulothoracic movement. There may be bruising below the clavicle. If there is a lack of resistance where the CCL should be, then this could suggest a fracture with incomplete CCL rupture. With posterior dilocation the scapula may be protracted and the entire shoulder girdle may be shorted and asymmetrical, with little if any visible swelling. Tracheal and/or oesophageal compression can occur with the patient having stridor, dysphagia, or shortness of breath. This requires emergent joint reduction which can be achieved in a closed method if acute, but if persistent then open surgery may be required due to distorted adherent vessel tissue behind the joint due to inflammatory changes.

Compression and thrombosis of the subclavian vein can occur. In this situation the patient may have venous congestion of the face and upper limb. Subclavian artery compression is rare and may be suggested by unequal pulses. If suspicious then angiography may be required. Chest x-ray is required in order to exclude a pneumothorax, pneumomediastinum, and haemopneumothorax. Brachial plexopathy is possible and can occur following direct trauma, compression, or traction. These can be managed conservatively if it is a closed injury.

Radiological Investigations

Radiographs

Standard chest x-rays have a low sensitivity for detecting traumatic SCJ dislocation.

Serendipity view

In the cephalic-tilt or 'serendipity' view, the x-ray beam projects caudocephalically. In this view anterior dislocations are detected by a superiorly displaced medial clavicle, and posterior dislocations as an inferiorly displaced medial clavicle.

Heinig view

In this view the beam is directed perpendicular to the joint (i.e. oblique to the patient), while the patient is supine. This is a useful view. Dislocations are detected by looking at their relationship to the laterally projected manubrium.

CT

CT is superior to x-ray for diagnosing dislocation. It can provide high-resolution axial images, and a three dimensional reconstruction. It can identify abnormal anatomical variants that predispose the patient to instability.

MRI

MRI has a poorer resolution than CT, but can detect soft tissue injuries. Disc injury (especially in recurrent atraumatic instability), ligament disruption, and the adjacent neovascular structures can all be assessed. Contrast enhancement is often required to detect disc injuries.

Management

Anterior Dislocation

The acute anterior dislocation (7-10 days) can be reduced by closed manipulation under conscious sedation, or in an operating room under general anaesthesia. Place the patient supine, and put a bolster between the scapulae. Place the arm in neutral flexion and abduction. Apply pressure over the medial clavicle and traction the arm. This almost always reduces the dislocation. Place the arm in a sling that maintains scapular protraction for up to four weeks. Recurrence is very common at > 50%. For patients with persistent instability, open reduction and stabilisation can be considered.

Resources

See Garcia et al for an open access review on sternoclavicular joint instability. Also an older open access review by Sewell et al.

Literature Review

Literature Review

Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf

Articles from all years: PubMed search, Google Scholar search.

TRIP Database: clinical publications about evidence-based medicine.

Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,