Floating shoulder

Introduction

The term floating shoulder was first introduced by Herscovici in 1992 and comprised a fracture of the scapular neck and ipsilateral clavicle.

Goss described the Superior Shoulder Suspensory Complex (SSSC) and defined a floating shoulder as a double disruption of the SSSC.

The most commonly thought of form of the floating shoulder is the ipsilateral scapula neck and clavicle fracture, however many variations of floating shoulder exist, purely bony fractures or in combination with ligamentous disruption.

The implications of a floating shoulder are not hard and fast, I would suggest most should be treated operatively in part at least (fixation of the clavicle). However with undisplaced fractures it is possible to treat a floating shoulder non operatively with a reasonable outcome. Fixation of the scapula is more contentious.

The definition of significant displacement is once again not hard and fast, most authors on the subject would suggest medial displacement of the glenoid by more than 3 cm is significant. The amount of inferior angulation/ tilt of the scapula is also important.

Classification

See Clavicle for various classification systems of clavicle fracture.

Scapula neck Fractures

Surgical neck (black line) exits medial to coracoid, most common
Anatomical neck (white line), rare

Variations of floating shoulder

Clinical

Do a thorough neurovascular examination, and document any motor and sensory deficits clearly, neurological injury is not uncommon.

The shoulder may appear to droop, be lower than the opposite shoulder.

Radiography

Glenopolar angle GPA

GPA = Angle measured between a line connecting the most cranial with the most caudal point of the glenoid cavity (white line)and a line connecting the most cranial point of the glenoid cavity with the most caudal point of the scapular body (black line).

The GPA measures the obliquity of the glenoid articular surface in relation to the scapular body.

Normal is 30° to 45°

Glenoid inclination angle

Glenoid inclination = Angle measured between a line drawn perpendicular to the line connecting the most cranial with the most caudal point of the glenoid cavity and a line drawn perpendicular to the tangent along the medial border of the scapula.

Caudal dislocation of the glenoid is defined as an angle >=20°

CT has not been shown to dramatically alter the reliability of the angles above, however if considering surgical intervention I personally believe it dramatically improves your understanding of the nature of the injury.

Management

The treatment of a floating shoulder is dependant on several variables and as such a single all encompassing treatment algorhythm is not possible at the present time.

In principle undisplaced or minimally displaced fracture can be treated non operatively.

Displaced and significantly comminuted fractures require fine judgement as to the best form of treatment.

Surgical treatment options include:

ORIF of Clavicle alone
ORIF of Clavicle and scapula neck

Recent evidence supports ORIF of displaced, comminuted clavicle fractures based on the clavicle injury alone as such I would ORIF the clavicle based on these criteria.

The scapula and scapula neck can be difficult to access and stabilise and at present it has not been shown that scapula fixation is much better than ORIF of clavicle alone. Having said that, with the introduction of pre contoured scapula locking plates and less invasive approaches to the scapula neck it is becoming possible to undertake scapula fixation more readily.

References

Herscovici D Jr, Fiennes AG, Allgower M, Ruedi TP. The floating shoulder: ipsilateral clavicle and scapular neck fractures. J Bone Joint Surg Br, 1992;74: 362-4

Goss TP. Double disruptions of the superior shoulder suspensory complex. J Orthop Trauma, 1993;7: 99-106

Goss TP. Scapular fractures and dislocations: diagnosis and treatment. J Am Acad Orthop Surg, 1995;3: 22-33

Williams GR Jr, Naranja J, Klimkiewicz J, Karduna A, Iannotti JP, Ramsey M. The floating shoulder: a biomechanical basis for classification and management. J Bone Joint Surg Am. 2001 Aug;83-A(8):1182-7.

Linksvan Noort A, van der Werken C. The floating shoulder. Injury. 2006 Mar;37(3):218-27