Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Clavicle Fractures: Anatomy, Indications, and Complications

Anatomical Distribution & Age Considerations

The clavicle is the most commonly fractured bone in the body.
Middle Third (Midshaft): Accounts for approximately 80% of all fractures. It is the thinnest segment and lacks ligamentous reinforcement.
Lateral Third: Accounts for roughly 15% of fractures. These are prone to instability due to coracoclavicular ligament disruption.
Medial Third: Rare pattern representing roughly 5% of fractures. Most heal predictably with non-operative care.
Young Patients with Medial Pain: Always obtain a CT scan. The medial clavicular epiphysis is the last ossification center to fuse in the skeleton (up to age 22 to 25).

Fracture Location	Incidence (%)	Primary Management Strategy
Middle Third	~80%	Non-operative if non-displaced; ORIF if shortened or comminuted
Lateral Third	~15%	Variable; often requires fixation if ligaments are torn
Medial Third	~5%	Predominantly conservative; CT rule-out for physeal injury

Standard Non-Operative Protocol: Sling immobilization followed by staged physiotherapy.
Healing Rate: Conservative treatment achieves an approximate 85% success rate.
Callus Formation: Non-operative treatment produces robust secondary bone healing with visible peripheral callus. Rigid plating results in primary healing with minimal to no external callus.
Non-Union & Malunion Risks:
- Non-union develops in roughly 15% of conservatively treated cases.
- Symptomatic malunion occurs in approximately 10% of cases.
- Displacement greater than 1.5 cm increases the non-union rate up to 30%.
Functional Deficits: Symptomatic malunion or non-union may reduce shoulder girdle endurance and peak muscle strength.
Range of Motion: Long-term total active shoulder motion is essentially equivalent between operative and non-operative groups.

Inspection: Look for localized deformity, focal ecchymosis, and palpable subcutaneous prominence.
Skin Tenting: Marked displacement stretches the overlying skin, creating a risk of open conversion or necrosis.
Neurovascular Assessment:
- The brachial plexus and subclavian vessels course directly inferior to the middle third of the clavicle.
- High-yield anatomical relationship: The posterior cord of the brachial plexus is closely related to midshaft fragments.
- Innervation pearl: The clavicular head of the pectoralis major is innervated specifically by the lateral pectoral nerve.

Fracture displacement exceeding 100% (no cortical contact).
Shortening greater than 2.0 cm on panoramic bilateral shoulder views.
Severe segmental comminution.
Z-Type Fractures: Vertical or oblique intermediate fragments resemble the letter Z.
- The spike can penetrate downward toward the brachial plexus and subclavian vessels.
- Fixing this pattern acutely avoids hazardous neurovascular dissection during late non-union surgery.

Clinical Parameter	Operative Threshold
Cortical Displacement	Greater than 100% translation
Bony Shortening	Greater than 2.0 cm
Comminution Pattern	Segmental or vertical Z-type fragment
Skin Integrity	Threatened soft tissue envelope (tenting)

Construct Design: Pre-contoured anatomical clavicle plates. Locking screws are reserved for osteopenic bone; non-locking screws are standard in young bone.
Plate Position Options:
- Superior: Stronger biomechanical resistance against inferior bending forces.
- Anteroinferior: Reduces hardware prominence and lowers the risk of superior screw penetration into the chest.
Symptomatic Hardware: Hardware irritation is common. Roughly 30% of patients require a second surgery for plate removal after complete healing.
Supraclavicular Nerve Injury:
- Two to three cutaneous branches cross the clavicle in 97% of individuals.
- More than 50% of operative patients develop numbness in the infraclavicular zone.
- Numbness can persist past 1 year postoperatively.
- Safe zones extend 2.0 cm from the sternoclavicular joint and 2.0 cm from the acromioclavicular joint, but these windows are too small for plate placement.
Number Needed to Treat (NNT): Surgeons operate on roughly seven patients with displaced clavicle fractures to prevent a single non-union.

Diagnostic Imaging: Plain radiographs can hide non-unions due to cortical overlap. Obtain a CT scan with multiplanar reconstructions when non-union is suspected.
Dual Requirements for Healing:
- Biological Stimulation: Provide local autograft, iliac crest bone graft, or osteoinductive bone graft substitutes.
- Mechanical Stability: Rigid fixation using a superior pre-contoured plate engaging a minimum of three bicortical screws (six cortices) on each side of the non-union site.