Diagnosis of Acromioclavicular Joint Injuries

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1 PO Box 15 Rocky Hill, CT (860) ChiroCredit.com is proud to present a section from one of our continuing education programs: Physical Diagnosis 103 Diagnosis of Acromioclavicular Joint Injuries Instructor: Robert D. Schwer, DC Lecture: Most disorders of the acromioclavicular joint are related to trauma, although degenerative conditions of the joint can also affect its function. The most common source of injury is a fall, with impact on the superior aspect of the shoulder and the arm in adduction. Falls off a bike or a horse often produce this type of injury. Laterally directed force to the shoulder, as in a hockey player hitting the boards is another common mechanism of injury. If the arm is not used to absorb the force the acromioclavicular joint takes the impact. The direction and magnitude of the force determines the extent of the injury. There is atypical progression to acromioclavicular injury based on the amount of force involved. Often, the acromioclavicular ligaments take the initial distribution of force. If the force is of greater magnitude, the injury progresses to the coracoclavicular ligaments and then the deltoid and trapezius fascia. Fractures of the distal third of the clavicle are not common but should be looked for. This type of fracture may or may not also have concomitant coracoclavicular ligament disruption. Indirect force as with a fall on an elbow or outstretched arm may also result in acromioclavicular injury. Primarily, this results in injury to the acromioclavicular ligaments and capsule. This is because the coracoclavicular ligaments are relaxed with upward movement of the scapula relative to the clavicle. Injuries to the acromioclavicular joint should be considered in any patient with trauma to the shoulder, especially if the history indicates one of the typical mechanisms of injury. The patient may have visible abrasion or contusion over the superior aspect of the shoulder as a result of a fall. Swelling may be present and there may be prominence of the distal end of the clavicle. Remember that this prominence is due to downward sag of the upper extremity, not upward displacement of the clavicle. On initial presentation, the patient may tense the shoulder muscles or cradle the arm to the side masking the prominence of the clavicle. Swelling may additionally mask this prominence. As swelling subsides, the prominence becomes more apparent. Palpation will usually reveal local tenderness.

2 In type I injuries, pain on palpation may be the only finding. Swelling will make the direction of instability difficult to determine initially. As swelling and pain subside instability will be more easily recognized. Anteroposterior and superoinferior translation of the distal clavicle can then be easily assessed. Motion of the shoulder joint is usually restricted in abduction or cross-body adduction. However, with type I injuries, pain may only be produced with resisted testing of abduction or cross-body adduction and direct palpation of the acromioclavicular joint. Examination findings typical to each type of acromioclavicular joint injury are listed below: Type I: Mild to moderate pain and swelling. Athletes often continue to participate in the activity that caused the injury. Upper extremity ROM is usually comfortable except cross body adduction. Resisted testing will accentuate pain. The only obvious finding is tenderness to palpation. Type II: Moderate to severe pain over the A/C joint. If evaluated before swelling occurs slight prominence of the clavicle will be noted. Anteroposterior motion of the distal clavicle can be felt when stabilizing the shoulder and grasping the clavicle. Type III: Moderate to severe pain is present. Prominence of the clavicle may be masked by swelling or cradling of the arm. Abduction or cross-body adduction increases pain. On palpation the distal clavicle feels unstable both anteroposteriorly and superoinferiorly. Tenderness is present at the A/C joint and the coracoclavicular space. Type IV: Severe pain is present. Palpation of the clavicle will reveal posterior displacement of the distal end through the trapezius. The instability of the clavicle is not as noticeable as in a type III injury. ROM is much more painful than in type III. Type V: Findings are very similar to type III but with more displacement of the clavicle. The skin is severely tented and it appears as if the clavicle may protrude through it. Injury to the deltoid and trapezius are more severe. Type VI: With type VI, the shoulder appears flatter due to the downward displacement of the clavicle. The acromion is more prominent and palpable. This is a rare injury, and may present with neurologic deficits due to damage to upper roots of the brachial plexus. Rib fractures, pneumothorax or sternoclavicular joint injuries may be found also. Radiographic evaluation of these injuries is important. Standard AP radiographs of the shoulder often over-penetrate the A/C joint and make diagnosis difficult. An anteroposterior acromioclavicular joint view as well as a 15-degree cephalad tilt view is recommended. The cephalad tilt avoids superimposition of the spine of the scapula over the acromioclavicular joint. In this way, subtle fractures of the distal clavicle are more apparent. Axillary lateral views help evaluate the position of the clavicle relative to the acromion. This is very useful in type IV injuries. Weighted stress views can be used to differentiate type II from type III injuries. The patient is seated or standing with 15 pound weights strapped to the patients wrists. This will accentuate the difference between the injured and uninvolved shoulder. It is important to have the patient relax or muscle forces may lift the arm and mask the disruption of the joint. The same may happen if the patient holds the weights in their hands rather than strapping the weights to the wrists. It is best to use a 14X17-in.

3 cassette to get both shoulders on a single film. Compare the coracoclavicular space between the normal and injured shoulder. A difference of 25-40% increase in space is generally felt to be indicative of complete disruption of the coracoclavicular ligaments. Radiographic findings typical of each type of acromioclavicular joint injury have been described: Type I: Essentially normal compared to the uninvolved side. Type II: Slight widening of the acromioclavicular joint compared to the uninvolved side. With stress radiographs, the coracoclavicular space is maintained. Type III: The joint is totally displaced on AP projection compared with the normal side. Axillary view fails to show anteroposterior displacement of the distal clavicle. Type IV: The AP view may show displacement of both the A/C joint and the coracoclavicular space. On the axillary view posterior displacement of the distal clavicle in relation to the acromion is most pronounced. CT scan for further evaluation may be needed. Type V: Gross displacement of the A/C joint and the coracoclavicular space. The coracoclavicular space may be two to three times wider than the normal side. Type VI: On AP projection, the clavicle will be seen inferior to the acromion or coracoid. Because of the large forces needed to produce this injury, other fractures of the ribs or scapula should also be ruled out. Conservative treatment of types I, II and III injuries is recommended initially. While treatment of type III can be done surgically, studies comparing operative and nonoperative treatment have shown similar results. Types IV, V, and VI require surgical intervention. Chiropractors are well placed to deliver conservative care to acromioclavicular injuries. Type I sprains of the AC joint are treated conservatively by all. Cold therapy is indicated in the acute phase to reduce swelling and pain. Active range of motion should be begun early on. Interferential current therapy is effective for both pain and edema. Strengthening exercises can be used to promote stability of the joint. Most patients will return to normal activity in two days to two weeks.

4 Courtesy of Primal Pictures, LTD. Figure 1. Type I Acromioclavicular sprain Type II injuries are treated similarly to type I early on. Cold therapy should begin immediately. A sling may be needed for the patient s comfort initially. Interferential current can be used to control pain as in type I. As the injury begins to heal active range of motion is instituted. Strengthening exercises follow. Return to activity is variable, and is based on restoration of motion, strength and patient comfort. Courtesy of Primal Pictures, LTD. Figure 2. Type II Acromioclavicular sprain The trend in treatment of type III injuries has been towards a conservative approach. Icing and a sling are used initially. Analgesics may be needed. Due to pain and deformity, return to normal activities will be slower as will the progression to active rehabilitative exercise. Bracing to correct the deformity has slowly fallen out of favor. TO be effective the brace must be worn six to eight weeks and any displacement of the brace during this time, will cause loss of reduction and subsequent failure. The brace can be cumbersome and painful. The trend is away from using them. Some patients with type III injuries will require surgery after the failure of conservative care.

5 Courtesy of Primal Pictures, LTD. Figure 3. Type III Acromioclavicular sprain NOTE: This is only one section of the Physical Diagnosis 103. If you enjoyed this material, please visit and take the entire one-hour program. Registration for the website is free and courses run between $20-$24 per credit hour With state-of-the-art technology, ChiroCredit offers online continuing education credits and ways to participate in other distance learning opportunities. Save time and money! No longer will you miss hours from your practice and family. You can obtain continuing education credits in the comfort of your own home or office at hours convenient to you while saving on travel and hotel expenses as well. To learn more, visit