Scapular and Clavicle Fractures

Sternoclavicular Joint

Anatomy

Diarthrodial jt, both jt surfaces covered by fibrocartilage
Artic surface of clavicle larger than that of the sternum, jt surfaces not congruent

Ligaments

intraarticular disc- fibrocartilage, divides jt into 2 cavities, rarely perforated
- runs from synchondral junction of 1st rib + sternum to sup + post aspect of med clavicle. Ant and post it blends with the capsule.
- acts to prevent med displacement of the med clavicle
Costoclavicular lig ( = rhomboid lig) - form the upper surface of the 1st rib and synchondral junction with the sternum to the rhomboid tubercle on the inf surface of the clavicle. Has 2 laminae - run in same pattern as the int and ext oblique muscles.
- ant fibres act to prevent upward motion of the clavicle
- post fibres act to prevent downward motion of the clavicle
Interclavicular lig - connects the superomed ends of each clavicle with the capsule and the upper sternum
- acts to prevent upward motion of the med clavicle
Capsule - thickened ant and post with the post being strongest
- prevents upward displacement of the med clavicle

Ossification

the clavicle is the 1st long bone of the body to ossify ( 5th intrauterine wk)
the med epiphysis is the last to appear (~ 18 ) and last to close ( ~ 25)
The capsule attaches to the epiphysis and the costoclavicular lig attaches to the metaphysis.
Thus in a SH 1 injury the costoclavicular lig is detached from the metaphysis or torn while the capsule and epiphysis remain intact.
In a SH 2 injury the costoclavicular lig remains attached to the distal fragment comprising the epiphysis and a piece of metaphysis

Classification

Anterior - most common, caused by lat compression with the shoulder rolling backward
Posterior - uncommon, caused by lat compression with the shoulder rolling forward
Injuries to the jt can be

sprain
acute dislocation
recurrent dislocation
unreduced dislocation

Symptoms and signs

severe pain increased by any movement of the arm ( post more painful than ant )
the affected shoulder appears shortened and thrust forward cf the normal side

Anterior

the med clavicle can be observed and palpated ant to the sternum
med clavicle may be fixed or mobile

Posterior

the med prominence of the normal clavicle is absent
the med clavicle is not palpable
may be venous congestion
breathing or swallowing difficulties
pneumothorax
shock due to damage to great vessels

XRay

AP view difficult to interpret
Hobbs view - pt seated, leans over table with arms up and head resting in hands, cassette on table ~ under pts neck, XR beam directed vertically down
Serendipity view : pt supine, 40 deg cephalic tilt view
Tomography
CT - gold standard

Treatment

Sprain: Rest, sling, gradual return to activity

Dislocation, anterior

most ant dislocations are unstable - notwithstanding -

CR - GA, pt supine, sandbag under centre of back
assistant pushes shoulders back
surgeon pushes clavicle back into place
in most cases this will not remain reduced - pt counselled that the risks of ORIF outweigh the cosmetic benefits of reduction
postreduction - if stable - clavicular rings to maintain position
if unstable - sling, gradual return to activity
NB cosmetic and functional deficit minimal if unreduced


Dislocation, posterior

once reduced are usually stable
may need to involve thoracic surgeon if mediastinal structures compromised

CR - GA, pt supine, sandbag under centre of back
gentle traction in line of clavicle, countertraction by assistant - this alone may reduce the dislocation
if not reduced, add manipulation with a towel clip - will reduce with clunk
rarely CR fails therefore ® OR
same position, free drape arm
involve thoracic surgeon
incision parallel to med 7-10 cm clavicle
reduction -
if stable treat as for CR
if unstable - excise the med 1- 1.5 cm clavicle and secure the remaining clavicle to the 1st rib with dacron tape
post op - clavicular rings 6 wks

Unreduced dislocation

Anterior
functional and cosmetic deficit minimal if any - no treatment indicated

Posterior
due to risk to mediastinal structures - OR indicated ( as above)


Clavicular Fractures

Classification

Type 1

middle 1/3 fractures ~ 80%

Type 2

distal 1/3 fractures ~ 15%

minimal displacement bw conoid and trapezoid ligs
ie both ligs intact
(a). fracture med to coracoclavicular ligs - displaced
(b). fracture bw conoid and trapezoid lig - displaced - ie conoid lig ruptured, trapezoid lig intact
intraartic fracture of AC jt - no lig disruption or displacement
Paediatric: ligaments intact attached to periosteum while prox frag displaces up through the disrupted periosteal sleeve
Comminuted with ligaments not attached prox or dist, but an inferior, comminuted fragment

Type 3 prox 1/3 fractures ~ 5%

minimal displacement
signif displacement ie ligs ruptured
intraarticular
epiphyseal separation - children and young adults
comminuted

Assoc injuries

Skeletal AC and SC dislocations
head and neck injuries
fracture 1st rib
Scapulothoracic dissociation
Lung and pleura PTX or haemothorax
tears of trachea or main bronchi
Brachial Plexus ulnar n most often involved in direct trauma
Vascular unusual - vessels protected by subclavius and deep cervical fascia

Mechanisms of injury

birth trauma clavicle compressed against maternal symphysis in a cephalic presentation or direct traction in a breech deli