01/09/2025
⚡Pathophysiology Of AC Joint Injury
- Trauma causes tearing of AC ligament → if severe, also coracoclavicular ligament.
- Leads to loss of clavicle–scapula stability.
- Depending on severity → subluxation or complete dislocation of clavicle upward relative to acromion.
Graded using Rockwood classification (Type I–VI):
- Type I: AC ligament sprain, no displacement.
- Type II: AC ligament torn, CC ligament sprained, slight displacement.
- Type III: Both AC & CC ligaments torn, obvious displacement.
- Type IV–VI: Severe displacement with posterior, superior, or inferior clavicle dislocation.
⚡ Symptoms
- Localized pain over AC joint.
- Swelling, tenderness, and possible bruising.
- Pain worsens with overhead or cross-body movements.
- Visible deformity (step-off sign) in higher grades.
- Limited shoulder ROM due to pain.
⚡Assessment
- History: Mechanism of injury (fall on shoulder, FOOSH).
- Inspection: Deformity, swelling, prominence of distal clavicle.
- Palpation: Tenderness at AC joint.
- Range of Motion: Painful, especially abduction and horizontal adduction.
- Strength: Reduced due to pain.
⚡ Special Tests
1. Cross-Body Adduction (Scarf Test)
- Patient flexes shoulder 90° and adducts across body.
- Pain over AC joint = Positive.
2. O’Brien’s Test (Active Compression Test)
- Shoulder flexed 90°, adducted 10–15°, internally rotated (thumb down).
- Patient resists downward pressure.
- Pain localized at AC joint = Positive.
3. Paxinos Sign
- Examiner squeezes acromion against clavicle (thumb on posterolateral acromion, fingers on clavicle).
- Pain = Positive.
8. Medical Management
- Type I–II (Mild to moderate):
- Rest, Ice, NSAIDs (ibuprofen, diclofenac).
- Arm sling for comfort (1–2 weeks).
- Type III: Conservative in most, surgery only if severe instability or high-demand athlete.
- Type IV–VI: Usually require surgical stabilization (AC joint reconstruction or fixation).
