Acromioclavicular Separation

  • Also known as a “shoulder separation”
  • Traumatic injury to the acromioclavicular (AC) joint with disruption of the AC ligaments +/- the coracoclavicular (CC) ligaments
  • The vast majority of patients with these injuries can be placed in a sling and discharged with orthopaedic follow-up

  • Mechanism
    • Direct blow such as a fall onto an adducted shoulder is most common
    • Common athletic injury (e.g. football, snowboarding, etc.)
  • Timing of injury
    • Acute vs. chronic
  • Other locations of pain
    • Must rule out injuries to the head and neck
    • Rule out associated fractures (e.g. clavicle, humerus, etc.)
  • Numbness or tingling?
    • Severe injury can injure brachial plexus
  • Hand dominance (right vs. left hand dominant)
  • Profession
  • Sporting involvement
    • Often occurs in athletes (high level versus recreational athlete)

    Vitals

  • Deformity - abnormal contour of the shoulder compared to contralateral side
    • Threatened skin (tented and blanched skin) or open injury (traumatic arthrotomy)
      • If traumatic arthrotomy, ensure 2-3g of IV cefazolin (Ancef) given, consult to orthopaedic surgery
  • Tender to palpation over the AC joint
  • Palpate the remainder of the upper extremity and clavicle to assess for other injury

Motor Exam:
  • Axillary nerve
    • Assess function by getting the patient to push elbow posteriorly into the gurney
    • Typical abduction of the shoulder is difficult to assess secondary to pain
  • Median Nerve/ Anterior interosseous nerve (AIN)
    • Opposition of the thumb
      • Opponens innervated by the median nerve - helpful to assess if concern for acute carpal tunnel syndrome
    • Flexion of wrist, fingers, thumb
    • “A-OK sign” = AIN
      • Tests flexion of thumb IP joint (FPL) and flexion of index DIP joint (FDP)
  • Radial nerve/ Posterior interosseous nerve (PIN)
    • Extension of wrist, fingers, thumb
      • Radial nerve palsy is common seen in humeral shaft fractures especially midshaft and distal third
    • “Thumbs up” = PIN
      • Tests extension of thumb IP and MCP joints (EPL))
      • Palm on flat surface and lifting/extending thumb off the surface is also a good test for PIN (tests extension of thumb MCP joint (EPL))
  • Ulnar nerve
    • Finger abduction (spread fingers, “peace sign”), finger adduction, cross fingers (“promise”)
Sensory Exam:
  • Median, Radial, Ulnar nerve distributions
    • Radial: Dorsal first web space
    • Median: Volar distal index finger
    • Ulnar: Volar distal small finger
Vascular exam:
  • Radial artery, Ulnar artery
    • If having difficulty with palpation of radial artery, find a US doppler
  • Capillary refill to digits

  • Likely limited ROM about the shoulder secondary to pain

  • AP/Scapular Y/axillary lateral vs. velpeau shoulder, Zanca view
    • Can obtain radiographs of contralateral side for comparison if needed
    • Axillary lateral view - confirm shoulder is in concentric alignment
    • Axillary lateral vs. Velpeau of shoulder
      •
      • Important to rule out concomitant shoulder dislocation which may not always be apparent on AP
        • Axillary
          • Beam directed into the axilla
          • Requires patient to abduct which might be painful in the setting of proximal humerus fracture
        • Velpeau
          • Superoinferior view looking down upon shoulder
          • Does not requires patient to abduct arm
    • Zanca view
      • Is a special view to look down the plane of the AC joint with minimal superimposition of bony structure which may obscure more traditional views
      • Performed by tilting the XR beam 10-15 degrees cephalad

     Medical Decision Making

Closed AC Separation without Tenting Skin :
*** is a *** y/o ***R/L hand-dominant individual with a history of *** presenting with an injury to the *** shoulder which occurred while ***, found to have a closed AC separation. On exam, the patient is neurovascularly intact with no poke holes or punctate wounds or tenting skin. There is tenderness to palpation and localized edema about AC joint. Radiographs reveal ***. The patient was placed in a sling and will follow up with orthopaedic surgery within 7-10 days.
Open or Tenting AC Separation :
*** is a *** y/o ***R/L hand-dominant individual with a history of *** presenting with an injury to the *** shoulder which occurred while ***, found to have an open/tenting*** AC separation. On exam, the patient is neurovascularly intact with an open wound/tenting skin*** about the AC joint. The patient was given ***ancef/gentamicin immediately after identifying the open injury. Radiographs reveal ***. Orthopaedics was consulted and will provide further recommendations. The patient is npo and last ate ***.

If open injury:
  • Consult orthopaedic surgery immediately
  • NPO, preop labs (type and screen, INR, aPTT, CBC, BMP)
  • Ensure IV antibiotics were given (ancef, gentamicin)
    • Gustillo-Anderson chart for antibiotic type and dose
If threatened skin (tenting with poor capillary refill):
  • Consult orthopaedic surgery immediately
  • NPO, preop labs (type and screen, INR, aPTT, CBC, BMP)
All other isolated AC separations:
  • WB status: Nonweightbearing injured upper extremity, remain in sling
  • Diet: Regular
  • Analgesia: short course of narcotic pain medication, tylenol (scheduled)
    • Ex: 5mg oxycodone q4 - 25 pills
  • Immobilization
    • Sling immobilization
  • Disposition: Home with follow up in orthopedic surgery clinic in 1 week

Common ICD-10 Codes Brief Description
S43.11 Subluxation of acromioclavicular joint
S43.12 Dislocation of acromioclavicular joint, 100%-200% displacement
S43.13 Dislocation of acromioclavicular joint, greater than 200% displacement
S43.14 Inferior dislocation of acromioclavicular joint
S43.15 Posterior dislocation of acromioclavicular joint
S43.16