Instability

Acromioclavicular Joint Sprain

Common shoulder injury. Rockwood classification in 6 types. Conservative treatment for types I-III, surgical for types IV-VI.

The acromioclavicular (AC) joint sprain is a common shoulder injury, especially in contact sports (rugby, judo, cycling falls). It results from a direct impact on the shoulder tip with a downward force. The Rockwood classification distinguishes 6 types based on severity: type I (ligament stretch), type II (AC ligament rupture, intact coracoclavicular (CC) ligaments), type III (complete AC + CC rupture, 100% superior clavicular displacement), types IV-VI (severe displacements requiring surgery). Types I-III are generally treated conservatively with good functional results. The debate persists for type III in overhead athletes or heavy laborers.

Characteristics

  • Pain at the top of the shoulder, localized at the AC joint. "Piano key" sign in types III+: the clavicle drops when pressed and rises back up. Bruising over the AC joint.
  • Bilateral AP radiograph (comparison with the other side): measurement of coracoclavicular distance (normal 1.1-1.3 cm). Increase > 25% = type III minimum.
  • Cross-body adduction test (forced horizontal adduction) reproduces the pain. Painful palpation of the acromioclavicular joint.
  • Types IV-VI: severe dislocations with posterior (IV), major superior (V) or inferior (VI) displacement of the clavicle. Formal surgical indication.

Medical and surgical management

  • Types I-III: conservative treatment in the majority of cases. Arm sling, NSAIDs, physiotherapy. Functional outcomes generally excellent.
  • Types IV-VI: surgical stabilization by coracoclavicular ligament reconstruction (screw, endobutton, tendon graft). Arthroscopic techniques in development.
  • Type III in heavy laborers or overhead athletes: case-by-case surgical discussion. Recent studies show comparable results between conservative and surgical treatment.

Physiotherapy rehabilitation

  • Types I-II: relative rest, cryotherapy (15 min / 4x daily), comfort sling for 1-2 weeks. Early progressive shoulder mobilization.
  • Type III: sling immobilization for 3-4 weeks then progressive rehabilitation. Strengthening of scapular stabilizers and deltoid.
  • Post-surgical rehabilitation (types IV-VI): immobilization 4-6 weeks, then passive mobilization, active-assisted, and progressive strengthening.
  • Return to sports: types I-II in 2-4 weeks, type III in 6-12 weeks, post-surgical in 4-6 months. Protective taping for sports.

Classification

  1. Rockwood I — Simple sprain

    Stretch of acromioclavicular ligaments. No displacement. Conservative treatment.

  2. Rockwood II — Subluxation

    Rupture of acromioclavicular ligaments. Coracoclavicular ligaments intact. Moderate subluxation.

  3. Rockwood III — Complete dislocation

    Rupture of all ligaments. 100% superior clavicular displacement. Treatment debated.

Average duration

3 to 12 weeks depending on type

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Scientific sources

General information only: this content cannot provide a diagnosis or prescription. A healthcare professional must assess your situation.