Type IV: AC + CC torn, clavicle posterior displacement
Urgent orthopaedic referral (likely ORIF)
Type V: AC + CC torn, CC distance >100%
Urgent orthopaedic referral (likely ORIF)
Return to Sport Criteria
Full ROM without pain
No AC joint tenderness
No pain with abduction/overhead activity
Can weight-bear on an outstretched hand
Complications
Post-traumatic OA
Chronic pain, impingement, instability with lifting/sports
Cosmetic deformity (step-off, common in III–V, benign)
Note:
Type III: Controversial; conservative favoured. Surgery if persistent symptoms or high functional demands
AC Joint Dislocation
Definition
A traumatic injury to the shoulder where the acromioclavicular (AC) joint, connecting the clavicle and the acromion, becomes disrupted
Commonly caused by a direct fall or blow to the lateral shoulder, often in contact sports or high-impact activitiesMay also occur from an outstretched arm mechanism leading to upward force on the humerus
Anatomy of the coracoclavicular joint (RACGP)
Types
Type I – AC and coracoclavicular (CC) ligaments intact
Type II – Torn AC ligament; CC ligaments remain intact
Type III – Both AC and CC ligaments torn, CC distance <100% of opposite side
Type IV – Both AC and CC ligaments torn, clavicle displaced posteriorly
Type V – Both AC and CC ligaments torn, CC distance >100% of opposite side
X-ray images of acromioclavicular dislocation: (a) anteroposterior view bilateral shoulders and (b) axial view.
Management
Type I & II & III (Conservative)
Broad arm sling for pain relief, typically 2–3 days
Analgesia (e.g. paracetamol, NSAIDs) and ice therapy
Early referral to physiotherapy for guidance on gradual range-of-motion exercises and scapular stabilisation work
Avoid contact sports for approximately 3–6 weeks, depending on pain and function
Most Type III injuries are managed conservatively, unless high functional demands or persistent pain indicate surgical review
Type IV & V (Surgical)
Urgent orthopaedic referral for likely open reduction and internal fixation (ORIF)
More common in high-demand athletes, labourers, or cases with significant displacement
Examination and Investigations
Tenderness over the AC joint and visible step-off deformity (especially in Type III–V)
Special tests such as the cross-arm adduction test can help localise AC joint pain
Plain X-rays (AP, axillary lateral, and/or specialised views) to assess CC distance, displacement, and rule out associated fractures
MRI considered if additional soft tissue or rotator cuff injury is suspected
Return to Sport Criteria
Full, pain-free range of motion in the shoulder
No tenderness on palpation of the AC joint
No pain on abduction or overhead activity
Ability to weight-bear through an outstretched hand without discomfort
Protective padding may be considered for contact sports
Complications
Post-traumatic osteoarthritis of the AC joint
Chronic pain and possible impingement
Instability or weakness with lifting and sporting activities
Cosmetic deformity (step-off), more common in Type III–V injuries
Notes
Type III management remains controversial: conservative is generally preferred, but surgery can be indicated for athletes, labourers, or cases with ongoing pain and dysfunction
Physiotherapy is crucial for maintaining and restoring shoulder strength and stability
Prognosis for Type I–III is generally excellent with appropriate rehabilitation and a graded return to activity
