SECTION D: SHOULDER DISORDERS

ACROMIOCLAVICULAR JOINT SEPARATION

CONDITION/DISORDER SYNONYMS

• Separated Shoulder

• AC separation

• AC dislocation

• Shoulder Separation

ICD-9-CM CODES

• 840.0 Acromioclavicular (joint or ligament) sprain

• 831.04 Closed dislocation of acromioclavicular (joint)

• 831.14 Open dislocation of acromioclavicular (joint)

ICD-10-CM CODES

• S43.109A Unspecified dislocation of unspecified acromioclavicular joint, initial encounter

• S43.50XA Sprain of unspecified acromioclavicular joint, initial encounter

PREFERRED PRACTICE PATTERN

• 4E: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated with Localized Inflammation¹

KEY FEATURES

Description

• Inflammation, irritation, or separation of the joint between the clavicle and acromion (AC joint)²

• Three ligaments of stability:

  • Acromioclavicular ligament²

  • Coracoacromial ligament

  • Coracoclavicular ligament: Made up of the conoid ligament and trapezoid ligament²

Essentials of Diagnosis

• Patient history and clinical examination

• X-ray

• Occurs most often from falling on an outstretched arm or hand

• AC separation occurs when the ligaments are completely torn and there is a dislocation of the joint

• Look for separation of the clavicle and acromion

• Step deformity often noticed when the clavicle is raised due to ligament tearing

• Six grades of sprain to separation: Rockwood Scale

  • Grade I

    • Slight displacement of the joint

    • Partially torn AC ligament

    • Separation <4 mm

  • Grade II

    • Partial dislocation of the joint

    • Complete disruption tear of the AC ligament

    • Partial disruption of the coracoclavicular ligament

    • Separation >5 mm

  • Grade III

    • Partial dislocation of the joint

    • Complete disruption tear of the AC ligament

    • Complete disruption/rupture of the coracoclavicular ligament

  • Grade IV

    • Dislocation of the joint

    • Posterior displacement

    • Requires surgery

  • Grade V

    • Dislocation of the joint

    • Superior displacement

    • Requires surgery

  • Grade VI

    • Dislocation of the joint

    • Inferior displacement

    • Requires surgery

General Considerations

• Not a synovial joint.

• Osteoarthritis is common without treatment or with prolonged instability.

Demographics

• Predominately in individuals with a history of activities involving overhead reach: Swimming, tennis, and baseball as well as with occupational activities involving repetitive overhead activity

CLINICAL FINDINGS