Acromioclavicular Joint Injury 

Updated: Oct 22, 2018
Author: Brett D Owens, MD; Chief Editor: Craig C Young, MD 

Overview

Background

Injuries in and around the shoulder, including acromioclavicular joint injuries, occur most commonly in active or athletic young adults. However, pediatric acromioclavicular injuries have also increased owing to the rising popularity of dangerous summer and winter sporting activities. Proper knowledge of the different problems and treatment options for shoulder disorders is necessary to help patients return to their preinjury state.

Acromioclavicular joint injuries are often seen after bicycle wrecks, contact sports, and car accidents. The acromioclavicular joint is located at the top of the shoulder where the acromion process and the clavicle meet to form a joint (see the following image). Several ligaments surround this joint, and depending on the severity of the injury, a person may tear one or all of the ligaments. Torn ligaments lead to acromioclavicular joint sprains and separations.[1]

The distal clavicle and acromion process can also be fractured. Injury to the acromioclavicular joint may injure the cartilage within the joint and can later cause arthritis of the acromioclavicular joint.

Treatment of acromioclavicular separations has been a subject of debate. In general, types I and II injuries are treated nonoperatively in the acute setting, and types IV, V, and VI injuries generally require surgical repair. However, reaching a consensus regarding the optimal management of acute type III injuries has been difficult (see Treatment).[2]

Anatomy

The acromioclavicular joint is made up of 2 bones (the clavicle and the acromion), 4 ligaments, and a meniscus inside the joint. The normal width of the acromioclavicular joint is 1-3 mm in younger individuals; it narrows to 0.5 mm or less in individuals older than 60 years.

The acromioclavicular joint is a diarthrodial articulation with an interposed fibrocartilaginous meniscal disk that links the hyaline cartilage articular surfaces of the acromial process and the clavicle. The joint is horizontally and vertically stabilized in anterior and posterior translation by a combination of dynamic muscular and static ligamentous structures, which allow a normal anatomic range of motion. Because of the transverse orientation of the articulation, direct downward forces may result in shear stresses that cause disruption of these stabilizing structures and create displacement beyond the normal limits. This is evidenced by abnormal positioning of the clavicle relative to the acromion, usually in the superior direction.

The acromioclavicular capsular ligaments provide most of the joint stability in the anteroposterior (AP) direction.

The 2 coracoclavicular ligaments (the conoid and the trapezoid ligaments) are found medial to the acromioclavicular joint and attach from the coracoid process on the scapula to the inferior surface of the distal clavicle. These ligaments provide vertical (superior-inferior) stability to the joint (see the following image).[3, 4] Compression of the joint is restrained mainly by the trapezoid ligament. The deltoid and trapezius muscles are especially important in providing dynamic stabilization when these ligamentous structures are damaged.

Torn acromioclavicular joint ligaments and/or torn coracoclavicular ligaments are seen in acromioclavicular joint sprains. The meniscus that lies in the joint may also be injured during sprains or fractures around the acromioclavicular joint.

The coracoacromial ligament runs from the superior surface of the coracoid process to the inferior surface of the acromial process in a nearly horizontal direction. Although it is not an acromioclavicular joint–stabilizing structure, during operative repair of type III acromioclavicular injuries, the coracoacromial ligament may be resected from its acromial insertion and used to reconstruct the torn coracoclavicular ligament. (See Pathophysiology for the classification of acromioclavicular injuries.)

The superior shoulder suspensory complex (SSSC) is a bony and soft-tissue ring composed of the glenoid process, the coracoid process, the coracoclavicular ligament, the distal clavicle, the acromioclavicular joint, and the acromial process at the end of a superior bony strut (the midshaft clavicle) and an inferior bony strut (the junction of the lateral scapular body and the medial glenoid neck).

Type III, IV, V, and VI acromioclavicular separations are double disruptions of the SSSC characterized by disruptions of both the coracoclavicular and acromioclavicular ligaments. As a result, these constitute unstable injuries that must be accounted for or that require surgical reduction and stabilization.[5]

Pathophysiology

Multiple indirect forces can result in an acromioclavicular joint injury. The most common mechanism for an acromioclavicular joint injury is a fall directly onto the acromion, with the arm adducted up against the body. When a person falls onto their shoulder, the force pushes the tip of the shoulder down. The clavicle is usually kept in its anatomic position, whereas the shoulder is driven down, which injures the different ligaments or causes a fracture. A fall onto an outstretched hand (FOOSH injury) and a downward force on the upper extremity have also been implicated in acromioclavicular joint injuries.[1, 6, 3]

The severity of an acromioclavicular separation is dependent upon the degree of ligamentous injury. When the ligaments are injured they are either sprained or, in more severe cases, torn. Severe forces resulting from significant falls are often associated with type III-VI injuries.

Classification of adult acromioclavicular joint injuries

Acromioclavicular joint sprains have been classified according to the severity of injury to the acromioclavicular and coracoclavicular ligaments, the acromioclavicular joint capsule, and the supporting muscles of the shoulder (trapezius and deltoid) that attach to the clavicle.[7]

An acromioclavicular joint sprain is more common than a fracture after an injury. However, fractures of the distal clavicle and the acromion process may occur, so the healthcare provider must be aware of such injuries and ready to diagnose and treat them as well (see Clavicular Injuries).

Allman and Tossy initially proposed a 3-grade classification[8, 9] that Rockwood expanded to 6 types of injury (see the following images).[10, 1] Type I and II injuries are the same in both classification schemes, with type III injuries in the Tossy classification subdivided into grades III, IV, V, and VI in the Rockwood classification. Type I-III acromioclavicular injuries are the most common injuries.

Classification of acromioclavicular joint injuries Classification of acromioclavicular joint injuries.
Allman/Rockwood classification of acromioclavicula Allman/Rockwood classification of acromioclavicular injuries.

The Rockwood classification of acromioclavicular injuries in adults is as follows[10, 1, 8, 9] :

  • Type I: Minor sprain of the acromioclavicular ligament, intact joint capsule, intact coracoclavicular ligament, intact deltoid and trapezius

  • Type II: Rupture of the acromioclavicular ligament and joint capsule, sprain of the coracoclavicular ligament but intact coracoclavicular interspace, minimal detachment of the deltoid and trapezius

  • Type III: Rupture of the acromioclavicular ligament, joint capsule, and coracoclavicular ligament; elevated clavicle (≤100% displacement); detachment of the deltoid and trapezius

  • Type IV: Rupture of the acromioclavicular ligament, joint capsule, and coracoclavicular ligament; posteriorly displaced clavicle into the trapezius; detachment of the deltoid and trapezius

  • Type V: Rupture of the acromioclavicular ligament, joint capsule, and coracoclavicular ligament; elevated clavicle (>100% displacement); detachment of the deltoid and trapezius

  • Type VI (rare): Rupture of acromioclavicular ligament, joint capsule, and coracoclavicular ligament; the clavicle is displaced behind the tendons of the biceps and coracobrachialis

In a type I sprain, a mild force applied to the acromioclavicular and coracoclavicular ligaments does not tear them.[8, 9, 11] The injury simply results in a sprain, which hurts, but the shoulder does not show any gross evidence of an acromioclavicular joint dislocation.

Type II sprains are seen when a heavier force is applied to the shoulder, disrupting the acromioclavicular ligaments but leaving the sprained coracoclavicular ligaments intact.[8, 9, 11] When these injuries occur, the lateral clavicle becomes a little more prominent.

As noted earlier, type III, IV, V, and VI acromioclavicular separations are double disruptions of the superior shoulder suspensory complex (SSSC).[8, 9, 11]

In type III sprains, the force applied to the shoulder completely disrupts the acromioclavicular and coracoclavicular ligaments, leading to complete separation of the clavicle and obvious changes in appearance. The lateral clavicle is very prominent.

Type IV injuries are defined by posterior displacement of the clavicle relative to the acromion with buttonholing through the trapezius muscle.

In type V injuries, the clavicle is widely displaced superiorly relative to the acromion as a result of disruption of muscle attachments.

The rare type VI injuries are characterized by inferior displacement of the distal clavicle below the acromial process or the coracoid process.

Pediatric acromioclavicular injuries

Acromioclavicular joint injuries in children are relatively uncommon, and they differ anatomically from such injuries in adults. The immature clavicle is encased in a periosteal tube. The coracoclavicular ligament is within this tissue, whereas the acromioclavicular ligament is exterior to it. This anatomic relationship explains why the acromioclavicular ligament is frequently injured with direct trauma, whereas the coracoclavicular ligament remains intact.

The pediatric Rockwood classification of acromioclavicular injuries is as follows[12] :

  • Type I: Stable clavicle; radiographically normal joint

  • Type II: Partial tear of the periosteal tube, allowing for some mobility of the distal clavicle; disrupted acromioclavicular ligament

  • Types III-VI: Larger tear through the periosteal tube, allowing for greater clavicle mobility and gross instability with clavicle positioning; the coracoclavicular ligament remains attached to the clavicle periosteal tube

When evaluating a pediatric radiograph, remember that incomplete closure of or failure of an ossification center may appear to be a fracture.

Etiology

The most common mechanism of injury to the acromioclavicular and coracoclavicular ligaments is a direct force applied to the superior aspect of the acromion, usually from a fall with the arm in an adducted position. This impact drives the acromion inferiorly, spraining the intra-articular acromioclavicular ligaments. If the force is great enough, the extra-articular coracoclavicular ligament may also be damaged.

Less commonly, an indirect force may be transmitted up the arm as a result of a fall on an outstretched hand (FOOSH injury). The force continues through the humeral head to the acromial process, displacing it superiorly and stressing the acromioclavicular ligaments. The coracoacromial ligaments are not injured with this type of mechanism.

Other injuries, depending on the force of injury, may include tears of the deltoid and trapezius attachments at the clavicle and fractures of the acromion, clavicle, and coracoid (or of their cartilaginous attachments).

Epidemiology

United States statistics

The true incidence of acromioclavicular injury is not known, as many affected individuals do not seek treatment. Approximately 12% of all dislocations involving the shoulder affect the acromioclavicular joint.

Athletes participating in contact sports (eg, football, rugby, hockey, martial arts) are at increased risk of acromioclavicular joint injuries,[13, 14, 15] and injuries to the acromioclavicular joint are the most common reason that athletes seek medical attention following an acute shoulder injury (glenohumeral dislocations are the second most common injuries seen) (see Shoulder Dislocation). Patients involved in motor vehicle collisions with direct trauma to the apex of the shoulder are also at risk for such injuries.

Males are more commonly affected than females, with a male-to-female ratio of approximately 5:1,[1] and younger individuals (< 35 y) sustain more acromioclavicular injuries, primarily due their greater participation in high-risk activities. Men in their second through fourth decades of life have the greatest frequency of acromioclavicular joint injuries, which are most often incomplete tears of the ligaments.[1]

No difference in injury patterns exists among various racial or ethnic backgrounds.

Prognosis

Significant morbidity is negligible with type I and II acromioclavicular injuries.

For type I injuries, the prognosis following nonoperative care is excellent. Affected patients may usually return to sports in 1-2 weeks. Some studies have shown mild symptoms occurring in approximately 30% of heavy laborers, but significant symptoms are much less common.[16, 17]

Following nonoperative management of type II injuries, patients in most long-term studies have shown good-to-excellent outcomes as well. These patients usually require a longer period of recovery that those with type I injuries, usually returning to sports in 2-4 weeks.

However, a small portion of the population with type II injuries will report symptomatic acromioclavicular degenerative disease that necessitates surgery. Reports exist of patients with type II injuries who continue to experience some subjective loss of strength up to 3 years after injury. Although the literature does not contain studies investigating the natural history of acromioclavicular joint degenerative disease, some studies report that athletes with distal clavicle osteolysis often experience resolution of symptoms with avoidance of provocative activities.[18, 19]

Morbidity is highest with type III injuries, which may be due to the controversy surrounding management. However, those treated nonoperatively generally do quite well. There is a scarcity of literature regarding long-term follow-up after surgical repair of type III.

Types IV, V, and VI injuries generally do well with surgical repair. Published studies of patients undergoing both arthroscopic and open resection have reported good or excellent results in approximately 60-100% of cases of acromioclavicular joint injuries. A 2007 prospective comparison of open versus arthroscopic treatment and retrospective studies have shown similar long-term results. Patients undergoing arthroscopic treatment are likely to return to activity more quickly than other patients.[20, 21]

Mortality is not commonly associated with acromioclavicular injuries.

Complications

Just like any other joint in the body, once the acromioclavicular joint has been injured, it has a tendency for arthritis and pain, with pain in the joint being the most common problem after these injuries. In type III sprains, the most common setback is also instability in the clavicle from the torn ligaments.

Acromioclavicular separations may be accompanied by fractures and other disruptions, as well as by injuries to nonorthopedic systems. Most frequent are midclavicular, distal clavicular, acromial, and coracoid fractures.[22, 23]

Degenerative changes involving the acromioclavicular joint are common late complications. Symptomatic traumatic arthritis may develop following nonoperative management of type I or II injuries. Surgery is often indicated to alleviate symptoms. However, symptomatic acromioclavicular joint arthritis may also develop in patients who undergo surgical management acutely.

Impingement symptoms, muscle-fatigue discomfort, and/or neurovascular symptomatology may occur in patients treated nonoperatively for type III separations and may require a surgical reconstruction.

Postoperative complications may also arise. The most common complication is mild residual instability after ligament reconstruction. This complication was more common when screws, sutures, suture tape, and Kirschner wires (K-wires) were being used to repair coracoclavicular ligament tears. Migration may also occur if pins or wires are used for fixation. Other postprocedure complications include osteomyelitis, soft-tissue ossification, and failure of fixation with recurrent deformity. Infections (eg, wound infection) may also occur, but these are rare, occurring less than 1% of the time.

When a patient is dealing with an arthritic acromioclavicular joint, the most common problem is inadequate resection of the clavicle during surgery. This causes continued acromioclavicular joint pain in these patients, but it is easily fixed with proper arthroscopic resection of the fragment.

Other complications from acromioclavicular joint injuries may include the following:

  • Cosmetic deformity

  • Accelerated osteoarthrosis

  • Decreased shoulder range of motion/upper extremity strength

  • Distal clavicle osteolysis

 

Presentation

History

An acromioclavicular joint injury should be considered in any patient complaining of pain over the superior part of the shoulder,[24] particularly after a fall either onto the apex of the shoulder or onto an outstretched hand. Patients may also notice restricted shoulder motion.

In the immediate setting, the patient may initially experience generalized shoulder tenderness and swelling; however, as the diffuse pain resolves, specific point tenderness over the acromioclavicular joint is usually noted.

The athlete may note a significant abrasion or prominence of the distal clavicle. Athletes involved in weight training typically experience pain with specific exercises such as with use of the bench press and dips.

Many individuals experience nocturnal pain and awakening when rolling onto the involved shoulder, which puts pressure on the acromioclavicular joint. Rarely, the patient may report popping or catching in the region of the acromioclavicular joint.

Physical Examination

Patients have pain over the acromioclavicular joint. Swelling, bruising, and a prominent clavicle may be evident, depending on the type of sprain that the patient has sustained. In types I and II sprains, deformity is usually minimal.

In type III injuries, the distal clavicle is abnormally prominent. A prominent clavicle with loss of the normal contour of the shoulder caused by sagging of the acromion is highly suggestive of a ligamentous disruption of the acromioclavicular joint. Of note, clavicle fractures, without acromioclavicular joint sprains, can also cause the clavicle to be prominent.

With an acute injury, the patient has poor shoulder range of motion and moderate pain when trying to raise the arm. These patients can often be seen carrying the affected arm close to the side of their bodies. Alternatively, patients use the unaffected arm to splint the injured extremity. These findings may be clearer when the patient is asked to hold a 10- to 15-lb weight in the hand of the affected arm.

In the acute situation, the examiner may have difficulty ruling out a concomitant rotator cuff tear, as active and passive shoulder abduction maneuvers are difficult to perform in the face of an acromioclavicular joint separation.

The most reliable physical examination test for acromioclavicular joint pathology is the cross-body adduction test. This test assesses the stability of the affected shoulder and should be performed by manipulating the midshaft of the clavicle rather than the acromioclavicular joint itself. The patient elevates the arm on the affected side 90°, while the examiner grasps the elbow and adducts the involved arm across the body.

Although reproduction of pain with this maneuver may occur in patients with posterior capsule tightness or subacromial impingement, pain is suggestive of acromioclavicular joint pathology. Restriction of range of motion, which is rarely associated with acromioclavicular joint pathology, more likely suggests adhesive capsulitis or glenohumeral arthritis.

 

DDx

Diagnostic Considerations

Patients with suspected acromioclavicular joint injuries should undergo a standard shoulder examination, including evaluation of range of motion, palpation of the bony structures of the shoulder for any stepoff that might suggest occult fracture, and assessment of neurovascular status to rule out brachial plexus injury (although concomitant neurovascular injury is relatively rare in acromioclavicular joint injuries).

Other problems to consider include the following:

  • Glenoid labrum tear

  • Septic arthritis

  • Erb-Duchenne injury

  • Distal clavicle osteolysis

Differential Diagnoses

 

Workup

Approach Considerations

Distinguishing acromioclavicular injuries from other shoulder injuries (ie, clavicular fractures, shoulder dislocations, proximal humeral fractures) is difficult.

Standard radiographs are usually adequate to confirm the diagnosis of acromioclavicular joint injury. The clavicle and scapula should also be assessed for any associated fractures.

To optimally image the acromioclavicular joint, obtain a cross-body adduction radiograph. Additionally, a radiograph of the entire upper thorax is useful to compare the vertical distance between the clavicle and the coracoid process on both sides. Radiographic results according to severity of injury are as follows:

  • Type I: Normal

  • Type II: Subluxation of the acromioclavicular joint space is less than 1 cm; normal coracoclavicular space

  • Type III: Subluxation of the acromioclavicular joint space is greater than 1 cm; widening of the coracoclavicular space is more than 50%

  • Types IV-VI: Subluxation of the acromioclavicular joint space is more than 1 cm, and widening of the coracoclavicular space is more than 50%; there is associated displacement of the clavicle

With complete acromioclavicular/coracoclavicular ligament rupture, cross-body adduction films will show the scapula rotated anteromedially, and the acromion will migrate medially.

Athletes with a previous history of acromioclavicular injury or a history of heavy weight lifting may present with relatively acute shoulder pain over the distal clavicle, and they may have classic radiographic findings of distal clavicle osteolysis or of acromioclavicular osteoarthritis (ie, joint narrowing, distal clavicle or acromial spurring). When these radiographic findings are present, the clinician may expect that seemingly little trauma can result in significant pain.

Radiography

As with all skeletal injuries, in cases of suspected acromioclavicular joint injury a minimum of 2 radiographic views (eg, anteroposterior [AP], lateral, axillary views of the shoulder; lateral projection of the scapula [scapular Y]) is necessary to evaluate the individual injury.[25] For pediatric injuries, plain radiographs may reveal fractures at the base of the coracoid.

If the athlete has sustained concomitant rib fractures with shortness of breath, good quality chest radiographs are indicated. A consultation from a pulmonary physician or cardiovascular chest surgeon may be necessary.

AP, lateral, and axillary views of the shoulder

The AP view should be taken with the patient’s arms at the side, and both acromioclavicular joints should be imaged for comparison. If a true AP view is obtained, the acromioclavicular joint can be seen superimposed on the spine of the scapula; hence, some authorities have recommended the Zanca view, in which 10-15° of cephalic tilt of the radiographic beam provides a clearer image of the acromioclavicular joint. (See below.)

Anteroposterior (AP) radiograph of right shoulder Anteroposterior (AP) radiograph of right shoulder showing step-off of the acromioclavicular (AC) joint.
Type III acromioclavicular joint separation. Type III acromioclavicular joint separation.

An axillary lateral view is also needed in suspected acromioclavicular joint injuries to account for any anterior or posterior displacement of the distal clavicle.

Stress views of the shoulder

Stress radiographs can be used to more accurately assess the integrity of the ligamentous structures by showing the degree of displacement of the acromion relative to the clavicle. If an unstable acromioclavicular joint injury is suspected, yet not confirmed on routine AP and lateral views, stress views may be indicated.

A 10- to 15-lb weight is attached to the wrist of the affected side, and an AP view can be taken. This stress tests the integrity of the coracoclavicular ligament and, if the ligament has been disrupted completely, the test will demonstrate the complete dislocation.

Routine use of stress radiographs is not recommended in the acute setting. Although these radiographs may help distinguish type I from type II injuries, many authorities consider such studies unnecessary, as any involuntary splinting by the patient prevents full visualization of the acromioclavicular joint and may simply serve to increase the patient's pain.

Weighted stress tests may be valuable in follow-up care if the clinician has any doubt about the instability of the acromioclavicular joint. Even with conservative care of type III-VI acromioclavicular disruptions, this test may be helpful for determining a timetable for the athlete’s return to conditioning and sporting activities.

Ultrasonography

Heers and Hedtmann reported that ultrasonographic examination of the acromioclavicular joint in experienced hands had 100% sensitivity for diagnosis of deltoid muscle detachment and fascial disruption.[26] The study also showed 80% sensitivity and 100% specificity for disruption of the trapezius muscle. A study by Faruch Bilfeld et al also found that ultrasound is an effective examination for the diagnostic work-up of lesions of the coracoclavicular ligaments in the acute phase of an acromioclavicular injury.[27] However, more studies are necessary to evaluate the potential for additional information provided by ultrasonography in the routine examination of suspected acromioclavicular injury.

Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is not routinely ordered in the management of straightforward acromioclavicular disruptions, although it has been shown to be helpful in differentiating between type II and type III injuries.[28] Such detailed knowledge of acromioclavicular and coracoclavicular ligamentous injury is generally not needed for conservative or, in rare cases, surgical care.[25]

Clinicians may consider an MRI to evaluate for a possible rotator cuff tear in middle-aged and older patients who continue to have disabling shoulder pain after the acute pain of an acromioclavicular disruption abates. In highly competitive athletes, MRI may be considered to further delineate the extent of the acromioclavicular injury.

Very rarely, athletes with persistent pain over the acromioclavicular joint merit an MRI to determine whether or not the cartilaginous disk has been damaged irreversibly and to determine whether or not the process of distal clavicle osteolysis or early osteoarthritis has begun.

 

Treatment

Approach Considerations

Treatment of acromioclavicular separations has been a subject of debate. Type I and II injuries are generally treated nonoperatively in the acute setting, and types IV-VI injuries generally require surgical repair. However, reaching a consensus regarding the optimal management of acute type III injuries has been difficult, despite randomized trials that indicate success with nonoperative treatment in most cases.[29, 30, 31]

Conservative versus surgical management

For types I-III injuries in pediatric patients, closed reduction can be effective, although surgical intervention for selected cases may be indicated to achieve better functional results. As a result, surgical correction should at least be considered in younger, more active patients or younger patients who are unsure of their future careers, as well as for heavy laborers and soldiers.[32, 1, 33]

In most adult patients with type III injuries, nonoperative care achieves an excellent functional outcome. However, many surgeons believe that this degree of displacement leads to muscle-fatigue discomfort and difficulty manipulating heavy loads.

Type I-III injuries that are managed conservatively may result in persistent shoulder pain, dysfunction, or both. Type I and II separations may progress to develop symptomatic degenerative disease. Type III separations may result in impingement symptoms, muscle-fatigue discomfort, and/or neurovascular symptomatology. Late surgical management may be required.

Fractures in and around the acromioclavicular joint are mostly treated conservatively in a sling. The few times surgery needs to be considered are when there is a moderate amount of displacement of the fracture fragments. Surgery is indicated for open fractures, neurovascular injury, and for those cases in which the skin is compromised and may rupture from the pressure of the prominent bone.

Injuries that lead to arthritis of the acromioclavicular joint are also first treated with conservative measures. Anti-inflammatory medication and intra-articular steroid injections work well for degenerative changes in the acromioclavicular joint. In injuries that have failed conservative therapy, excision of the distal clavicle can be performed with a minimally invasive arthroscopic procedure.[34]

A systematic review and meta-analysis by Chang et al that compared outcomes between operative and nonoperative management of types III-V acromioclavicular joint dislocations reported that the operative group had better cosmetic outcome and radiographic reduction and that the nonoperative treatment was associated with faster return to work, however, no significant clinical difference in functional outcome scores were seen between the two groups.[52]

Operative intervention

In general, surgical management should be offered acutely only to those who require high-level upper extremity function and late to those with significant shoulder pain and/or dysfunction refractory to nonoperative treatment. Given the proper choice of treatment, outcomes should be acceptable in more than 90% of patients.[1]

The current criterion standard is to reconstruct the torn coracoclavicular ligaments with either local tissue or an allograft. However, many procedures have been described for the repair of acute and chronic type III-VI injuries.[35, 36, 37, 38, 39, 40, 41] These all include open reduction and stabilization of the dislocation with repair of the usually torn deltotrapezial fascia and debridement of the acromioclavicular articulation.

Bosworth described the use of a screw placed from the clavicle into the coracoid base to stabilize the articulation,[42] whereas others have used bioabsorbable or nonbioabsorbable devices passed through a drill hole in the clavicle and around the coracoid base. Pins placed through the acromion, across the acromioclavicular joint, and down the clavicle have also been used. The acromioclavicular ligaments and coracoclavicular ligament are repaired, if possible. Many authors have also advocated performing a distal clavicle excision at the time of the operative repair, especially in late reconstructive procedures.[35, 36, 37, 38, 39, 40, 41]

Weaver and Dunn described a procedure designed to reconstruct the coracoclavicular ligament by excising the distal end of the clavicle and transferring the acromial attachment of the coracoacromial ligament to the resection site.[43, 44]

A study aimed to evaluate the vertical biomechanical behavior of two techniques for the anatomic repair of coracoclavicular (CC) ligaments after an acromioclavicular (AC) injury. The study concluded that anatomic repair of coracoclavicular ligaments with a double system (double tunnel in the clavicle and in the coracoid) permits vertical translation that is more like that of the acromioclavicular joint. Acromioclavicular repair in a "V" configuration does not seem to be biomechanically sufficient.[45]

Precautions

The presence of infection is a contraindication to repair of an acromioclavicular separation. Additionally, an open wound with compromised soft tissues may necessitate delay of the surgery until the risk of infection is minimized by irrigation and antibiotic prophylaxis. Other considerations include the patient's overall health and ability to undergo anesthesia.

Prehospital and Emergency Department Care

Acutely, acromioclavicular separations are generally quite painful. Prehospital providers should splint suspected acromioclavicular injuries in a position of comfort. Always check the neurovascular status of the injured extremity after application of a splint. If indicated, assess and immobilize the spine.

Acromioclavicular injuries requiring open reduction and internal fixation (ORIF) should be repaired within 2 weeks of the time of injury. Reduction of acromioclavicular injuries is rarely attempted in the emergency department. Such maneuvers should only be performed in cooperation with an orthopedic surgeon.[46] Unless other injuries are sustained, these patients do not require admission on the day of injury.

Orthopedic surgeons should also be consulted in pediatric cases and in adults with type III-VI acromioclavicular joint injuries.

Management of Type I and II Injuries

Acromioclavicular joint sprains do well with conservative management. Type I and type II injuries are generally accepted to be treated nonoperatively in the acute setting. A brief course of narcotics followed by nonsteroidal anti-inflammatory drugs in combination with locally applied ice and activity modification is usually sufficient for type I and II injuries.

However, these injuries may need further care if the acromioclavicular joint becomes arthritic from the injury (see below).

Postoperative coracoclavicular ligament reconstruc Postoperative coracoclavicular ligament reconstruction. The clavicle is back to its normal position. The anchor in the clavicle keeps the allograft tendon from coming off of the clavicle. Also note the distal clavicle has been excised, because it had traumatic arthritis from the injury.

Type I injuries involve minimal disruption of the acromioclavicular joint and are intrinsically stable. Treatment involves application of a sling for comfort and activity modification, ice, and analgesic agents until the symptoms subside and the range of motion is reasonably comfortable.

Athletes can usually return to sports in 1-2 weeks. For patients whose symptoms do not improve within this time frame, intra-articular steroid injections may be indicated. Patients with persistent pain for extended amounts of time may be candidates for a distal clavicle excision.

Type II

In patients with type II injuries, the acromioclavicular ligament is completely torn. For the most part, these patients receive the same treatment as those with type I injuries, in combination with a rehabilitation program that emphasizes maintaining or regaining range of motion. However, patients with type II injuries take longer to improve than those with type I injuries, because the acromioclavicular ligaments are disrupted. With significant instability, strap immobilization for 2-4 weeks and no heavy lifting for 6-12weeks are appropriate to allow healing and prevent progression to a type III injury.[47, 35]

A Kenny-Howard shoulder harness may be used for strap immobilization, although this device is frequently uncomfortable for the patient and may not change the outcome.

Late management of type II injuries may require intra-articular steroids or surgery. Distal clavicle excision has been noted to produce inferior results compared with the same surgery in patients with type I injury due to increased instability of the acromioclavicular joint.

Surgical intervention

When conservative measures fail to manage symptomatic acromioclavicular joint arthrosis after type I and type II injuries, a distal clavicle resection provides predictable relief. This can be performed in both an open manner and an arthroscopic manner.

The amount of bone that should be resected has been debated; original descriptions suggested 1-2 cm, and the arthroscopic advocates suggest less (5-7 mm). In general, adequate bone should be resected to prevent acromioclavicular contact during shoulder range of motion yet avoid violating the coracoclavicular ligament.

Management of Type III-VI Injuries

Type III

Patients with type III acromioclavicular injuries have complete tearing of both the coracoclavicular and acromioclavicular ligaments. This type of injury results in superior displacement and greater instability of the clavicle.

As noted earlier, there is controversy regarding the optimal management of type III injuries. Most studies suggest that conservative therapy produces better functional results than operative repair.[29, 30, 31] If nonoperative management is chosen after a type III separation, the treatment is similar to that for a type II injury.

However, comparison trials between operative and nonoperative management have suffered from an insufficient numbers of patients, a retrospective design in most cases, heterogeneous patient groups, or a lack of objective evaluation in the follow-up period. Furthermore, a variety of different surgical techniques have been developed, making comparison between conservative management and general operative management difficult.

Nissen and Chatterjee published a survey of members of the American Orthopaedic Society for Sports Medicine and accredited residency directors from the Accreditation Council for Graduate Medical Education (ACGME) in which they found conservative therapy is still the recommended first line of care for type III injuries (>90%).[48] An earlier meta-analysis of all studies looking at outcomes of acromioclavicular separations—consisting of 24 papers, 5 of which directly compared surgical and nonsurgical management of type III acromioclavicular injuries—appeared to conclude that nonsurgical intervention yielded improved strength, range of motion, and fewer complications than operative intervention.[49]

Surgical intervention

Surgical intervention may be an option in type III acromioclavicular joint sprains, but only after the patient's condition has failed a good trial of conservative treatment with physical therapy and medication. Some authorities indicate that individuals in certain active occupations, such as baseball pitchers, manual laborers, and soldiers, may disproportionately benefit from operative intervention.[32, 1, 33] The procedure for these patients is reconstruction of the torn coracoclavicular ligaments with either local tissue or an allograft.

In the past, surgeons have used screws, sutures, suture tape, synthetic grafts, and Kirschner (K)-wires to try to repair the type III defect. These have all fallen out of favor, and the current criterion standard is to reconstruct the torn ligaments as mentioned above.[50]

Leidel et al studied the operative outcome of acute grade III acromioclavicular joint separations after temporary K-wire transfixation in 70 patients and found no significant differences among patients divided into 3 groups: 1-2 years post procedure; 3-5 years post procedure; and 6-10 years post procedure.[32] All 3 treatment groups had good functional results and consistent outcome over the long term.[32]

In a cadaver study that assessed the capsular and ligamentous insertions around the acromioclavicular joint in 28 cadaveric shoulders to determine the amount of bone that can be removed without destabilizing the joint, Stine and Vangsness indicated that an acromioclavicular joint resection (5-7 mm) consisting of 2-3 mm from the medial acromion and 3-4 mm from the distal clavicle would not remove the acromioclavicular capsular insertions.[51] The investigators also noted that medial resections greater than 15 mm would begin to take down the trapezoid ligament and suggested that arthroscopic bone resection be directed into the acromioclavicular joint at approximately 50° in the axial plane and 12° in the coronal plane for safe symmetric resection.[51]

Type IV-VI Injuries

Type IV, V, and VI injuries in adults and pediatric patients generally require surgical repair. Because the clavicle is so far displaced from the acromial process in the posterior, superior, or inferior direction, respectively, conservative management is inadequate. The patient continues to experience pain and dysfunction if the articulation is not reduced and stabilized.

Type IV

In patients with a type IV injury, the deltotrapezial fascia is disrupted in addition to complete tears of the acromioclavicular and coracoclavicular ligaments. This injury complex allows posterior displacement of the clavicle into the trapezius and requires reduction, usually operative.

In theory, a closed reduction could be possible to convert the injury into a type III acromioclavicular injury, which could then be managed conservatively. Barring this possibility, surgery with an open reduction and internal fixation is necessary (ORIF).

Type V and VI injuries

Type V and VI acromioclavicular injuries are the most severe and will universally require ORIF. Acromioclavicular joint injection may be considered in the patient with recurrent visits to the emergency department for acromioclavicular pain. However, this is not recommended in the acute setting, as any fluid injected may complicate magnetic resonance imaging evaluation of the joint.

Physical Therapy

Acromioclavicular joint injuries are painful, and the patient often lacks full range of motion after the injury. Physical therapy plays a role in the treatment of these patients. Some clinicians routinely start therapy within the first couple of weeks in acromioclavicular joint sprains.

For fractures of the acromioclavicular joint, wait until evidence of healing is apparent either clinically or radiographically before starting formal therapy. Therapy for degenerative joint disease of the acromioclavicular joint has not been proven to be successful.

Activity

Some clinicians have strict return-to-sports criteria that they address with patients who have acromioclavicular joint injuries and with physical therapists. These criteria may include the following:

  • No swelling/pain with functional activity

  • Isokinetic strength that is 80% of the opposite rotator cuff

  • Full active and passive range of motion

  • Stable scapula through full range of motion, with a normal scapulohumeral rhythm

  • Pain-free activities of daily living (ADLs)

Long-Term Monitoring

Postoperative follow-up is important; this is mandatory for type III-VI injuries and recommended in all pediatric injuries. Patients are generally seen at 2-week intervals to monitor and update their rehabilitation program.

Patients undergoing reconstructive procedures remain in a sling for 2 weeks. Thereafter, a progressive, passive, range-of-motion program is begun. The patient's affected arm remains in the sling between sessions. At 6 weeks, healing is sufficient to allow patients to discontinue protection and to encourage progressive functional use.

Physiotherapy continues until the patient’s range of motion and strength are maximized. Heavy physical use of the shoulder is prohibited for an additional 6 weeks. Patients undergoing a distal clavicle resection are simply protected in a sling for 2 weeks to allow soft-tissue healing to occur.

If a coracoclavicular screw or a trans-acromioclavicular joint pin is used for stabilization, the device is removed 6 weeks postoperatively.

Prevention

Prevention of significant acromioclavicular joint degenerative pathology generally consists of early diagnosis of the problem and avoidance of causative maneuvers, if possible. Football shoulder pads may decrease the extent of an injury, but they by no means prevent acromioclavicular injuries.

For patient education resources, see Medscape Reference’s First Aid & Injuries Center articles on Shoulder Dislocation and Shoulder Separation.

Maintenance Phase

Rehabilitation Program

Content.

 

 

Medication

Medication Summary

The initial treatment of degenerative arthritis of the acromioclavicular joint may include the use of nonsteroidal anti-inflammatory drugs (NSAIDs), along with occasional corticosteroid injections.

Nonsteroidal Anti-inflammatory Drugs (NSAIDs)

Class Summary

NSAIDs have analgesic, anti-inflammatory, and antipyretic activities. The mechanism of action of these agents is not known, but they may inhibit cyclooxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well; these may include inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell-membrane functions.

Ibuprofen (Motrin, Advil, IBU-200, Caldolor, Addaprin)

Ibuprofen is the drug of choice for patients with mild to moderate pain. This agent inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.

Ketoprofen

Ketoprofen is used for relief of mild to moderate pain and inflammation. Small dosages are initially indicated in small and elderly patients and in those with renal or liver disease. Doses exceeding 75 mg do not increase the therapeutic effects. Administer high doses with caution, and closely observe patients for a response.

Naproxen (Naprelan, Anaprox, Naprosyn, Aleve)

Naproxen is used for relief of mild to moderate pain. This agent inhibits inflammatory reactions and pain by decreasing the activity of cyclooxygenase, which results in a decrease of prostaglandin synthesis.

Indomethacin (Indocin)

Indomethacin is rapidly absorbed; its metabolism occurs in the liver by demethylation, deacetylation, and glucuronide conjugation. This agent inhibits prostaglandin synthesis.

Diclofenac (Voltaren-XR, Cataflam, Zipsor, Zorvolex, Cambia)

Diclofenac inhibits prostaglandin synthesis by decreasing the activity of the enzyme cyclooxygenase, which in turn decreases the formation of prostaglandin precursors.

Sulindac (Clinoril)

Sulindac decreases the activity of cyclooxygenase and in turn inhibits prostaglandin synthesis. This process results in a decreased formation of inflammatory mediators.

Fenoprofen (Nalfon)

Fenoprofen decreases the formation of prostaglandin precursors by inhibiting cyclooxygenase (COX)–1 and 2 enzymes. It may also inhibit neutrophil aggregation/activation and chemotaxis and may alter lymphocyte activity and decrease proinflammatory cytokine levels.

Flurbiprofen

Flurbiprofen may inhibit COX, thereby inhibiting prostaglandin biosynthesis. These effects may result in analgesic, antipyretic, and anti-inflammatory activities.

Cyclo-oxygenase 2 Inhibitors

Class Summary

COX-2 inhibitors are used to control pain and inflammation, especially in cases of contraindication to conventional anti-inflammatories. Although increased cost can be a negative factor, the incidence of costly and potentially fatal GI bleeds is clearly less with COX-2 inhibitors than with traditional NSAIDs. Ongoing analysis of cost avoidance of GI bleeds will further define the populations that will find COX-2 inhibitors the most beneficial.

Celecoxib (Celebrex)

Celecoxib inhibits primarily COX-2, an isoenzyme induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity, but at therapeutic concentrations, COX-1 isoenzyme is not inhibited and thus, GI toxicity may be decreased. Seek the lowest dose of celecoxib for each patient.

Nonopioid Analgesics

Class Summary

Nonopioid analgesic agents are used for relief of mild to moderate pain. Acetaminophen (with or without an opiate) is the most commonly used analgesic.

Acetaminophen (Tylenol, Aspirin Free Anacin Extra Strength, Acephen, FeverAll)

Acetaminophen is the drug of choice for pain in patients with documented hypersensitivity to aspirin or NSAIDs, in those diagnosed with upper gastrointestinal disease, or in those taking oral anticoagulants.

Opioid Analgesics

Class Summary

Opioid agents are used for moderate to strong analgesic effects.

Hydrocodone bitartrate and acetaminophen (Vicodin ES, Lorcet 10/650, Lortab, Norco, Zydone)

The combination of hydrocodone bitartrate and acetaminophen is indicated for the relief of moderate to severe pain.

Acetaminophen and codeine (Tylenol with Codeine, Capital and Codeine)

The combination of acetaminophen and codeine is indicated for the treatment of mild to moderate pain.

Corticosteroids

Class Summary

Corticosteroid agents have both anti-inflammatory and salt retaining properties. Glucocorticoids have profound and varied metabolic effects. In addition these agents modify the body's immune response to diverse stimuli.

Hydrocortisone (Solu-Cortef, Cortef, A-Hydrocort)

Hydrocortisone decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing increased capillary permeability.

Triamcinolone (Aristospan Intra-Articular, Aristospan intralesional, Kenalog)

Triamcinolone is used for inflammatory dermatoses that are responsive to steroids. This agent decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing capillary permeability.

Methylprednisolone (Depo-Medrol, Solu-Medrol, A-Methapred, Medrol)

Methylprednisolone decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.

 

Questions & Answers

Overview

What are acromioclavicular joint injuries?

What are the treatment options for acromioclavicular joint injury?

What is the anatomy involved in an acromioclavicular joint injury?

What is the pathophysiology of an acromioclavicular joint injury?

How are acromioclavicular joint injuries classified?

What is the Rockwood classification of acromioclavicular joint injuries?

What is the pathophysiology of pediatric acromioclavicular joint injuries?

What is the pediatric Rockwood classification of acromioclavicular joint injuries?

What causes acromioclavicular joint injuries?

What is the prevalence of acromioclavicular joint injury in the US?

What is the prognosis of acromioclavicular joint injuries?

What are possible complications of an acromioclavicular joint injury?

What are possible postoperative complications of acromioclavicular joint injury?

What are possible complications of acromioclavicular joint injury in the presence of arthritis?

What are complications from acromioclavicular joint injuries?

Presentation

Which clinical history is characteristic of an acromioclavicular joint injury?

What are the physical findings suggestive of an acromioclavicular joint injury?

How is acromioclavicular joint pain tested in a physical exam?

How is acromioclavicular joint injury differentiated from other shoulder pathology during physical exam?

DDX

What is included in a shoulder exam for suspected acromioclavicular joint injuries?

What should be included in the differential diagnoses of acromioclavicular joint injury?

What are the differential diagnoses for Acromioclavicular Joint Injury?

Workup

What is the role of radiography in the diagnosis of acromioclavicular joint injury?

Which radiographic findings are diagnostic in the evaluation of acromioclavicular joint injuries?

What imaging findings are characteristic of athletes with a previous history of acromioclavicular joint injury?

How is radiography used to diagnose acromioclavicular joint injury?

How is imaging of the anteroposterior (AP) view performed to evaluate acromioclavicular joint injury?

What is the role of stress radiographs in the diagnosis of an acromioclavicular joint injury?

What is the role of ultrasonography in the evaluation of acromioclavicular joint injury?

What is the role of MRI in the workup of acromioclavicular joint injury?

Treatment

What are the treatment options for acromioclavicular joint injury?

What are conservative treatment options for acromioclavicular joint injury?

What is the role of surgery in the treatment of acromioclavicular joint injury?

What are contraindications to surgery for acromioclavicular joint injury?

What is included in prehospital and emergency department (ED) care of acromioclavicular joint injury?

What are the treatment options for type I and type II acromioclavicular joint injuries?

How are type I acromioclavicular joint injuries treated?

How are type II acromioclavicular joint injuries treated?

When is surgical intervention indicated for type I and type II acromioclavicular joint injuries?

How are type III acromioclavicular joint injuries treated?

When is surgical intervention indicated for type III acromioclavicular joint injuries?

Why is conservative management inadequate for the treatment of type IV-VI acromioclavicular joint injuries?

How are type IV acromioclavicular joint injuries treated?

How are type V and VI acromioclavicular joint injuries treated?

What is the role of physical therapy in the treatment of acromioclavicular joint injuries?

What is the return-to-sports criteria following treatment for acromioclavicular joint injuries?

What is included in long-term monitoring of acromioclavicular joint injuries?

How are acromioclavicular joint injuries prevented?

Medications

What is the role of medications in the treatment of acromioclavicular joint injuries?

Which medications in the drug class Corticosteroids are used in the treatment of Acromioclavicular Joint Injury?

Which medications in the drug class Opioid Analgesics are used in the treatment of Acromioclavicular Joint Injury?

Which medications in the drug class Nonopioid Analgesics are used in the treatment of Acromioclavicular Joint Injury?

Which medications in the drug class Cyclo-oxygenase 2 Inhibitors are used in the treatment of Acromioclavicular Joint Injury?

Which medications in the drug class Nonsteroidal Anti-inflammatory Drugs (NSAIDs) are used in the treatment of Acromioclavicular Joint Injury?