Anatomy of the Shoulder

The humeral head sits in the shallow socket of the scapula (the glenoid) to form the ball-and-socket glenohumeral joint. The joint surfaces are covered with cartilage; the labrum deepens the socket, and the rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis) hold the humeral head within it.

The clavicle connects the chest wall to the shoulder and provides a stable strut for shoulder movement. The scapula glides over the chest wall, enabling the wide arc of shoulder motion. A healthy shoulder allows raising the arm, reaching overhead, throwing and the fundamental movements of daily life without pain.

Proximal Humerus Fractures

These are fractures of the region of the humerus close to the shoulder. They may occur after a fall or a high-energy injury. The Neer classification is based on the number of fracture parts:

• One-part: displacement <1 cm or angulation <45°; may be treated non-operatively in some cases
• Two-part: a single anatomical part is displaced; surgery may be required
• Three-part: two anatomical parts are displaced; surgery is often required
• Four-part: all four anatomical parts are displaced; the blood supply to the humeral head may be compromised, and surgery (plate and screws or arthroplasty) is required
• Fracture–dislocation: fracture plus shoulder dislocation; urgent treatment is required
• Anatomical neck fracture: the blood supply to the humeral head is disrupted; the risk of avascular necrosis (bone death) is high
• Surgical neck fracture: the most common two-part pattern; surgical treatment often gives a good result
• Greater tuberosity fracture: the attachment site of the rotator cuff; displacement >5 mm requires surgery
• Lesser tuberosity fracture: the attachment site of subscapularis; uncommon

Clavicle (Collar Bone) Fractures

Clavicle fractures are divided into three regions according to the Allman / Robinson classification:

• Middle third (mid-shaft): the most common type (~80%); usually treated non-operatively, although surgery is preferred where there is marked displacement, comminution or shortening
• Distal (lateral) third: close to the acromioclavicular joint; surgery is required for displaced type II injuries (with rupture of the coracoclavicular ligaments)
• Medial third: close to the sternum; uncommon, high energy, and requires attention to possible mediastinal injury

Scapula (Shoulder Blade) Fractures

Scapular fractures account for less than 1% of all fractures; they usually result from high-energy injuries and require attention to associated injuries.

• Scapular body fracture: the most common type; most are treated non-operatively
• Glenoid (socket) fracture: intra-articular; surgery is required for displaced fragments, and some patterns may lead to shoulder instability
• Scapular neck fracture: surgery may be required where there is displacement and angulation
• Acromion fracture: may affect the rotator cuff outlet
• Coracoid process fracture: the attachment site of ligaments and tendons; uncommon
• "Floating shoulder": clavicle plus scapular fracture on the same side; more often requires surgery

Classification by Displacement and Joint Involvement

• Non-displaced fracture: the bone fragments have not shifted; most are suitable for non-operative treatment
• Displaced fracture: the fragments have shifted; surgical correction may be required
• Intra-articular fracture: the fracture line extends into the joint surface, increasing the long-term risk of arthritis
• Open fracture: uncommon; requires emergency surgery
• Stress fracture: caused by repetitive loading; may be seen in the clavicle, in athletes and in older patients

Symptoms

• Sudden, severe pain: at the moment of injury, prominent over the shoulder or collar bone
• Swelling and bruising: oedema and haematoma developing within the first hours
• Restricted movement: inability to raise the arm, difficulty with internal and external rotation
• Deformity: a visible prominence in displaced clavicle fractures (a "tenting" appearance); loss of the normal contour around the shoulder in proximal humerus fractures
• Tenderness: pain that increases on palpation of the fracture site
• Crepitus: a grating sensation or sound during movement
• Supporting the arm: the patient holds the arm close to the body with the other hand
• Altered sensation or coldness: if there is nerve or vascular injury (particularly the axillary nerve or brachial plexus)
• Open wound: loss of skin integrity in an open fracture
• Shortness of breath or chest pain: important as an indicator of associated lung or chest wall injury in scapular or high-energy fractures

Mechanisms of Injury

• Low energy: tripping or falling on level ground, falling onto the elbow or an outstretched hand (typical of proximal humerus fractures in older patients with osteoporosis)
• High energy: road traffic accidents (particularly motorcycle and bicycle), falls from height
• Direct blow: a direct impact to the shoulder or collar bone (typical of clavicle and scapular fractures)
• Sports injuries: falls from a bicycle, skiing, motocross, rugby, football
• Pathological fractures: with minimal trauma in the presence of bone tumour or metastasis
• Repetitive loading (for stress fractures)

Diagnosis

Diagnosis is based on a detailed history, physical examination and imaging. Examination assesses swelling, deformity, points of tenderness, range of motion, associated ligament injuries, neurovascular status (particularly the axillary nerve — sensation over the outer upper arm and deltoid contraction), pulses, skin integrity and the chest (for pneumothorax in scapular and high-energy injuries).

Plain radiographs are the first-line investigation; anteroposterior, scapular Y and axillary views for the proximal humerus, anteroposterior and cephalic tilt views for the clavicle, and anteroposterior and axillary views for the scapula are standard. CT is almost always required for intra-articular fractures (particularly glenoid and comminuted proximal humerus fractures) and for surgical planning; three-dimensional CT is critical for assessing fragment displacement. MRI is used to evaluate associated rotator cuff injury and soft-tissue pathology. Angiography or CT angiography may be required where vascular injury is suspected after a high-energy injury.

Non-operative (Conservative) Treatment

A sling or a body–arm bandage (Velpeau bandage) is used for stable, non-displaced or minimally displaced fractures. The sling is worn for an average of 3–6 weeks, after which graduated passive range-of-motion exercises begin.

• Non-displaced proximal humerus fractures (Neer one-part)
• Isolated minimally displaced mid-shaft clavicle fractures
• Most scapular body fractures
• Non-displaced glenoid fractures

Surgical Treatment (ORIF or Arthroplasty)

Surgery is performed for displaced or unstable fractures and for those that disturb the joint surface. Plates and screws, intramedullary nails, tension band techniques, cannulated screws, reverse shoulder arthroplasty or anatomical shoulder arthroplasty may be used.

• Displaced Neer three- and four-part proximal humerus fractures
• Comminuted four-part fractures in older patients (usually with reverse shoulder arthroplasty)
• Displaced mid-shaft clavicle fractures (>2 cm shortening, >100% displacement, comminuted fracture)
• Displaced distal clavicle type II fractures
• Displaced glenoid fractures (particularly of the anterior rim)
• Marked angulation in a scapular neck fracture; open fractures; cases with associated vascular or nerve injury

Advantages

The principal advantage is anatomical restoration of the fracture with rigid fixation. This reduces the long-term risk of malunion, non-union, disturbance of shoulder mechanics and post-traumatic arthritis. Whereas prolonged immobilisation in a sling during non-operative treatment can lead to shoulder stiffness, surgery allows early movement.

• Anatomical reduction: fragments are restored with millimetre precision and the joint surface is accurately repaired
• Early motion: stable fixation allows passive and active shoulder range-of-motion exercises to begin early, reducing stiffness related to sling immobilisation
• Prevention of clavicular shortening: in markedly shortened mid-shaft clavicle fractures, surgery restores anatomical length and improves shoulder mechanics
• Operative time: 60–90 minutes for clavicle fractures; 90–150 minutes for proximal humerus fractures; longer for reverse arthroplasty or complex cases
• Discharge after 1–2 days
• Shoulder function is better preserved in the long term; the risk of non-union and loss of function is higher after non-operative treatment of displaced fractures

Disadvantages

• You will need to wear a sling; moving the arm excessively during this period may lead to implant failure or loss of reduction in the early phase
• There are surgery-specific risks: wound infection, deep infection, implant failure, nerve injury (particularly the axillary nerve), rare vascular injury and rare anaesthetic complications
• Avascular necrosis of the humeral head: the blood supply may be compromised, particularly in anatomical neck and four-part fractures; collapse of the humeral head may occur even after ORIF and conversion to arthroplasty may be required
• Implant irritation: plates over the clavicle may cause irritation in patients with thin skin; implant removal may be required in 20–30% of patients once the bone has healed
• Shoulder stiffness may develop during immobilisation; frozen shoulder (adhesive capsulitis) may occur, particularly in older patients. This resolves with physiotherapy.

Why Surgery?

The shoulder has the widest range of motion of any joint in the body and is critical to many activities of daily life. In proximal humerus fractures, displaced fragments impair rotator cuff function, and advanced displacement threatens the blood supply to the humeral head.

Marked shortening in a clavicle fracture disturbs shoulder mechanics and scapular movement; the non-union rate in markedly displaced mid-shaft clavicle fractures treated non-operatively reaches 15–20%, whereas after surgery it falls below 5%. In glenoid fractures, incongruity of the joint surface leads to shoulder arthritis in the long term.

Who is a Candidate?

Surgery is performed for displaced or unstable fractures around the shoulder and for those that disturb the joint surface.

• Displaced Neer three- and four-part proximal humerus fractures
• Greater tuberosity fractures displaced >5 mm
• Markedly shortened (>2 cm) or comminuted mid-shaft clavicle fractures
• Displaced distal clavicle type II fractures
• Glenoid fractures involving the joint surface; open fractures
• Complex cases such as neurovascular injury or a "floating shoulder"
• Non-operative treatment: stable, non-displaced fractures; selected patients at very high surgical risk; most scapular body fractures

Expected Outcomes

Most patients with a correctly treated fracture around the shoulder achieve a pain-free, functional shoulder. Most return to daily activities within 3–6 months; complete recovery may take up to a year in some cases. Fracture healing takes 6–8 weeks in simple isolated fractures and 10–12 weeks or longer in complex or intra-articular fractures.

Success rates after surgery for clavicle fractures are high; in comminuted proximal humerus fractures in older patients, reverse shoulder arthroplasty has in recent years become an option that gives very satisfactory results.

Risks Specific to Non-operative (Sling) Treatment

• Inadequate reduction / secondary displacement: fragments shifting within the sling; further surgery may be required
• Skin problems: pressure sores and friction beneath the sling
• Shoulder stiffness / frozen shoulder (adhesive capsulitis): the most common complication, particularly in older patients
• Rotator cuff weakness: atrophy related to immobilisation
• Non-union: may reach 15–20%, particularly in displaced mid-shaft clavicle fractures
• Malunion: shortening and deformity of the clavicle with disturbance of shoulder mechanics

Risks Specific to Surgery — Common (Under 5%)

• Superficial wound infection (usually treated with antibiotics)
• Postoperative pain, swelling and temporary bruising
• Temporary joint stiffness — resolves with regular physiotherapy
• Temporary loss of strength — regained with rehabilitation
• Transient symptoms related to anaesthesia such as nausea and dizziness
• Temporary altered sensation after an interscalene block
• Scar discomfort (particularly over the clavicle)

Risks Specific to Surgery — Less Common

• Deep infection (osteomyelitis / implant infection): 1–3%; may require revision, implant removal and prolonged antibiotics
• Nerve injury: the axillary nerve (the most commonly affected in shoulder surgery), the suprascapular nerve and elements of the brachial plexus
• Vascular injury (very rare, under 1%)
• Pneumothorax (particularly with clavicle and scapular fractures)
• Implant failure: loosening or breakage of screws or plates, particularly in osteoporotic bone
• Avascular necrosis (bone death of the humeral head): particularly in anatomical neck and four-part fractures; may develop even after ORIF, with rates reaching 25–30%
• Heterotopic ossification (bone formation in soft tissue)
• Complex regional pain syndrome (CRPS / Sudeck's atrophy): skin colour change, pain and temporary bone loss. This is a fully reversible condition
• Deep vein thrombosis (DVT) / pulmonary embolism — rare in upper limb surgery

Long-term Complications

• Malunion: the bone heals in the wrong position, disturbing shoulder mechanics and increasing pain and the risk of arthritis; this is common with clavicular shortening
• Non-union: increased by smoking, diabetes, osteoporosis and early activity
• Post-traumatic osteoarthritis: may develop years later after intra-articular fractures (particularly glenoid and humeral head fractures); shoulder arthroplasty may be required in advanced cases
• Persistent shoulder stiffness (frozen shoulder)
• Rotator cuff weakness or tearing
• Chronic pain; chronic instability (particularly after glenoid fractures)
• Cosmetic deformity (in clavicle fractures)

Implant-related Problems

• Implant irritation close to the skin: a plate over the clavicle causes marked irritation in patients with thin skin; implant removal may be required in 20–30% of patients
• Need for implant removal: usually performed after 9–12 months, once fracture healing is complete
• Screw cut-out (a screw penetrating into the joint in an osteoporotic humerus): may occur with proximal humeral locking plate fixation

Factors that Increase Risk

• Smoking (markedly increases the risk of wound healing problems, non-union and infection)
• Poorly controlled diabetes (impaired wound healing)
• Osteoporosis (poor implant purchase, secondary displacement, screw cut-out)
• Peripheral vascular disease
• Immunosuppressive therapy and rheumatological disease
• Advanced age; high-energy or open fracture
• Active or recently treated infection (dental, urinary, skin)

Contact Your Doctor Immediately If You Have

• Sudden increase in pain or swelling
• Fever above 38 °C
• Discharge, malodour or separation of the wound
• Numbness, tingling or loss of strength in the arm, shoulder or hand
• Bruising, coldness or pallor of the hands or fingers (suspected vascular problem)
• Shortness of breath or chest pain (suspected pneumothorax or pulmonary embolism)
• Wound edge separation or exposed hardware
• Sudden change in the shape of the shoulder

Long-term Outcomes

With accurate diagnosis, appropriate treatment and compliant rehabilitation, the great majority of fractures around the shoulder heal without problems. Most patients return to daily activities within 3–6 months and to sport within 6–12 months. Complete recovery may take up to a year in some cases; stiffness may persist for 12 months, particularly after high-energy and complex proximal humerus fractures.

There is a risk of post-traumatic arthritis years later after intra-articular fractures; anatomical reduction, appropriate implant selection, early motion and compliant rehabilitation reduce this risk. Stopping smoking, controlling blood glucose and maintaining a healthy weight are critical factors for healing and long-term outcome.