Sports Medicine: Just the Facts

CHAPTER 46 • STERNOCLAVICULAR, CLAVICULAR, AND ACROMIOCLAVICULAR INJURIES 279

initially appeared to have minor injuries will have much

more obvious deformity and instability.

ACROMIOCLAVICULAR INJURY
CLASSIFICATION

• The two most commonly used classification system
  for injuries to the AC joint were described by Allman-
  Tossey and Rockwood.


• The Allman-Tossey classification is broken down into
  three grades:
  
  
  1. A type I injury involves a strain of the acromio-
     clavicular ligaments. There is usually some widen-
     ing of the AC joint on plain radiographs but no
     increase in the coracoclavicular interval.
  
  
  2. A type II injury involves tearing of the acromio-
     clavicular ligaments and strain of the coracoclavic-
     ular ligaments.
  
  
  3. A type III injury is characterized by complete rup-
     ture of the acromioclavicular and coracoclavicular
     ligaments.
  
  
  
  


• Rockwood felt that not all type III injuries were equiv-
  alent and further broke this type into type IV, V, and VI.
  
  
  1. A type IV injury involves complete rupture of the AC
     and CC ligaments; however, the clavicle is displaced
     posteriorly into or through the trapezius muscle.
  
  
  2. A type V injury represents a severe type III injury
     with significant displacement of the clavicle rela-
     tive to the acromion. Radiographically this is seen
     as a 100–300% increase in the distance between
     the clavicle and the coracoid.
  
  
  3. A type VI injury is a very rare event where the CC
     and AC ligaments are completely ruptured and the
     clavicle is displaced inferior to the coracoid. Only
     handfuls have ever been reported in the literature
     (Rowe, 1968).
  
  
  
  


• One of the most significant problems with these two clas-
  sification systems is that they are often used interchange-
  ably and there tends to be little interobserver reliability.

RADIOGRAPHIC EVALUATION

• It is difficult to obtain radiographs that adequately
  reflect the extent of the injury in the early postin-
  jury period. This is due to pain and the splinting of
  the shoulder girdle muscles. The most accurate
  radiographs are obtained a few weeks after the
  injury; however, if operative intervention is indi-
  cated, it is best performed within the first 2 weeks
  after injury.


• Standard radiographs should include an AP and axillary
  view of the shoulder. If there is posterior displacement

of the clavicle relative to the scapular, it can be seen

best on the axillary view.

• Stress radiographs, although commonly obtained in
  urgent care settings, are of questionable value because
  if the patient is actively guarding due to the pain of the
  injury, the results will not show the full extent of the
  injury.
  •A very useful view is the cross-body adduction radi-
  ograph. The radiograph is taken similar to a standard
  AP radiograph except that the patient is instructed to
  pull the elbow of the affected shoulder across their
  chest to the midline. Since the patients cannot splint or
  actively restrain motion of the shoulder in this posi-
  tion, subtle instability patterns can be detected in the
  early postinjury period. In the case of complete rupture
  of the AC and CC ligaments, the scapula will rotate
  anteriorly and medially relative the distal clavicle and,
  on this view, the acromion will appear to go medial
  and under the distal clavicle. If either of the CC liga-
  ments is intact, this will not happen. This obvious radi-
  ographic finding can easily differentiate severe injuries
  that may need operative intervention from lesser ones
  that can be treated nonoperatively (Basamania, 2000).


• In the case of high demand athletes with questionable
  injuries, MRI studies can be used to detect injuries to
  the AC and CC ligaments.

TREATMENT

•Few injuries have had as much controversy over treat-

ment as acromioclavicular joint injuries. Although

there is a consensus on the treatment of type I, II, IV,

V, and VI injuries, there is little, if any agreement, on

the treatment of type III injuries. Most studies support

nonoperative treatment of all type I and II injuries

while most studies support operative intervention in

type IV through VI injuries. To add further confusion,

many studies do not distinguish whether they are

referring to an Allman-Tossey type III injury or a

Rockwood type III injury, potentially including

Rockwood type IV–VI injuries in the former. An

equal number of studies showing good results from

both operative and nonoperative treatment of type III

injuries are found in the literature (Bergfeld, Andrish,

and Clancy, 1978; Bjerneld, Hovelius, and Thorling,

1983; Eskola et al, 1991; Galpin, Hawkins, and

Grainger, 1985).

• One particular exception to the treatment régime is the
  contact athlete. In those athletes who are high risk for
  a recurrent injury, such as a hockey player, it makes
  little sense to put them through an operative treatment
  program when they will probably go on to have
  another injury. It is better to wait until the end of their