Injury to the Acromioclavicular and Sternoclavicular Joints

Injuries to the acromioclavicular (AC) joint are common occurrences in the athletic patient population, with approximately 9% of all shoulder injuries involving the AC joint. Injuries to the sternoclavicular (SC) joint are less common, accounting for up to 3% of all shoulder girdle injuries. Damage to either of these joints can lead to significant limitations and pain, and as such, it is critical for the orthopaedic surgeon to recognize and treat these conditions. Studies have shown that the majority of AC joint injuries occur in young males and that injuries are often incomplete rather than complete. Although SC injuries are rare, disruptions to this joint can involve the critical airway and vascular structures just deep to the sternum, ultimately leading to life-threatening complications.

Numerous procedures, protocols, and a wealth of biomechanical testing have recently been devised to treat injuries to the AC and SC joints. This multitude of research with its various conflicting outcomes can lead to confusion regarding the choice of an appropriate treatment. In this chapter we focus on the relevant clinical and biomechanical anatomy of the AC and SC joints, treatment options and decision-making principles, and clinical outcomes reported in the literature. Specific attention is given to our preferred operative techniques. Although details regarding the history, physical examination, and imaging findings associated with AC and SC joint disease are discussed briefly in this chapter, these aspects are covered in detail elsewhere in this text.

Acromioclavicular Joint


Similar to other major joints, the AC joint is composed of its own joint capsule that contains an intraarticular meniscus-like structure. Eventually the meniscus-like structure undergoes age-related degeneration and has no function beyond the fourth decade of life. Articular cartilage lines both aspects of the articulation; however, the true articular portion of the distal clavicle varies with regard to location and size. In addition to the primary structures of the joint, the AC joint depends on a coordinated function of the AC, coracoclavicular (CC), and coracoacromial ligaments ( Table 60-1 ). The AC ligament acts as the primary restraint to anterior and posterior displacement of the AC joint. The CC ligament is unique because it is composed of the trapezoid and conoid ligaments. The two major functions of the CC ligament include mediating synchronous scapulohumeral motion by attaching the clavicle to the scapula and providing additional strength to the AC articulation. As a result, the CC ligament mainly contributes to vertical stability by preventing superior and inferior translation of the clavicle. Although it is not a primary stabilizer, the coracoacromial ligament provides secondary glenohumeral stabilization to prevent anterosuperior displacement of the humeral head in long-standing massive rotator cuff disease. Of note, the normal anatomic CC interspace is approximately 1.1 to 1.3 cm ( Figs. 60-1, 60-2, and 60-3 ).

TABLE 60-1

Summary of the Ligamentous Anatomy of the Acromioclavicular Joint

Ligament Origin Attachment Function Notes
Acromioclavicular: superior, posterior, anterior Anteromedial edge of the acromion Lateral aspect of the clavicle Provides horizontal stability Flattened tissue that joins the superior surface of the acromioclavicular joint capsule
Trapezoid (coracoclavicular) Upper coracoid process Oblique ridge on the inferior clavicle Provides vertical stability (less than a conoid ligament) Broad, thin, and quadrilateral; lateral to conoid
Conoid (coracoclavicular) Base of the coracoid process Conoid tubercle on the inferior clavicle Provides vertical stability (more than a trapezoid ligament) Dense and conical; medial to trapezoid
Coracoacromial Lateral border of the coracoid Anterior and inferior surface of the acromion just anterior to the clavicular articular surface Forms part of the coracoacromial arch, preventing superior migration of the humeral head Strong, dense, triangular band


Normal anatomy of the acromioclavicular joint.

(From Rockwood CA Jr, Williams GR Jr, Young DC: Disorders of the acromioclavicular joint. In Rockwood CA Jr, Matsen FA III, Wirth MA, et al, editors: The Shoulder , ed 3, Philadelphia, 2004, Elsevier.)


Resection or injury of the acromioclavicular ligaments causes horizontal instability and, if in excess, can cause abutment of the posterior clavicle into the anterior portion of the scapular spine.


Injury to both of the coracoclavicular ligaments frequently occurs in the face of acromioclavicular ligament injury and causes an inferior translation of the scapulohumeral complex from the clavicle. In this illustration it is important to note that the clavicle stays in its normal anatomic position, tethered by the sternoclavicular joint, and the scapulohumeral complex subluxates inferiorly.

Native Joint Biomechanics

During normal motion, approximately 5 to 8 degrees of motion is detected at the AC joint, with forward elevation and abduction to 180 degrees. The clavicle rotates between 40 and 50 degrees during full overhead elevation. This motion is combined with scapular rotation as opposed to occurring through the AC joint itself. This synchronous motion between the clavicle—which is rotating upward as the scapula rotates downward during abduction—and forward elevation was described by Codman as synchronous scapular-clavicular rotation, which is coordinated by the CC ligaments. The motion of the AC joint is important to understand clinically, because the contribution of different ligaments with regard to resisting translation changes depends on the amount of displacement. For example, with small displacements, the AC ligaments are most important in preventing posterior and superior translation of the clavicle; however, with larger amounts of displacement, the conoid ligament becomes the primary restraint to superior translation. The trapezoid ligament is vital in resisting compression at both small and large amounts of displacement ( Fig. 60-4 ).


Motions of the clavicle and the sternoclavicular joint. A, With full overhead elevation, the clavicle is elevated 35 degrees. B, With adduction and extension, the clavicle displaces anteriorly and posteriorly 35 degrees. C, The clavicle rotates on its long axis 45 degrees as the arm is elevated to full overhead position.

(From Rockwood CA, Green DP, editors: Fractures in adults , ed 2, Philadelphia, 1984, JB Lippincott.)


The pathologic process of AC joint dislocations involves sequential injury, beginning with the AC ligaments, extending to the CC ligaments, and finally affecting the deltoid and trapezial muscles and fascia. Tossy and colleagues originally developed a classification scheme that included types I, II, and III. Rockwood expanded the classification to include types IV, V, and VI ( Fig. 60-5 ).


The classification of the ligamentous injuries that can occur to the acromioclavicular (AC) joint. In a type I injury, a mild force applied to the point of the shoulder does not disrupt either the AC or coracoclavicular (CC) ligament. In a type II injury, a moderate to heavy force applied to the point of the shoulder disrupts the AC ligaments, but the CC ligaments remain intact. In a type III injury, when a severe force is applied to the point of the shoulder, both the AC and the CC ligaments are disrupted. In a type IV injury, not only are the ligaments disrupted, but the distal end of the clavicle is displaced posteriorly into or through the trapezius muscle. In a type V injury, a violent force applied to the point of the shoulder not only ruptures the AC and CC ligaments but also disrupts the muscle attachments and creates a major separation between the clavicle and the acromion. A type VI injury is an inferior dislocation of the distal clavicle in which the clavicle is inferior to the coracoid process and posterior to the biceps and coracobrachialis tendons. The AC and CC ligaments have also been disrupted.

(From Rockwood CA Jr, Williams GR Jr, Young DC: Disorders of the acromioclavicular joint. In Rockwood CA Jr, Matsen FA III, Wirth MA, et al, editors: The shoulder, ed 3, Philadelphia, 2004, Elsevier.)


The key element of the history for a patient presenting with a potential AC or SC joint injury is the mechanism of injury, which is usually related to direct trauma. The AC joint is considered to be vulnerable to traumatic injury because it lacks additional protection from muscle and adipose tissue as a result of its subcutaneous position. Direct trauma related to a fall or blow to the acromion with the arm adducted is often described. During such high-energy events, the innate stability of the SC joint results in a transfer of energy to the AC and CC ligaments, resulting in a dislocation of the AC joint. The AC joint can also be subjected to indirect trauma during a fall onto an adducted outstretched hand or elbow, resulting in superior translocation of the humerus, and ultimately resulting in a collision of the humeral head into the acromion. Although rare, nontraumatic injury to the AC joint can result from chronic overuse, referred to as AC arthrosis, which often results from a history of weight lifting and repetitive overhead or throwing activities ( Fig. 60-6 ).


Mechanism of acromioclavicular joint injury. A, Direct trauma as result of a fall or blow to the acromion with the arm adducted. B, Indirect injury caused by falling on an adducted outstretched hand or elbow, causing the humerus to translocate superiorly.

Physical Examination

Several physical examination techniques are available to help identify and isolate AC joint disease. The complete examination must include inspection, palpation, range of motion, strength, sensation, and stabilization assessments of both shoulders, after which special tests specific to the AC joint can be performed. The clinician should be aware of and test for any appropriate cervical spine and/or glenohumeral joint pathologic conditions that, if present, may confuse the clinical picture. Similarly, other disease processes including gout, pseudogout, and chondromatosis should be considered and ruled out.

The initial physical examination of the patient with a suspected AC joint injury should include observation of the patient. When examining a patient for suspected AC joint injuries, the clinician must be sure to examine the entire clavicle and AC joints because of the possibility of biclavicular dislocations. When the patient is sitting with both arms hanging freely, the weight of the arm helps accentuate any AC joint deformity. In this position, it can be possible to observe a superior prominence of the distal clavicle of the involved AC joint. In the event of an SC joint injury, it is often possible to readily observe a gross deformity, especially with an anterior dislocation or subluxation. In these situations the patient is likely to be seen supporting the affected extremity with his or her head tilted toward the affected extremity in an attempt to decrease stress across the joint.

After inspection, the clinician should attempt to isolate the location of the patient’s pain via direct palpation, which can be difficult in the acute situation because of diffuse inflammation and edema. In AC joint injuries, the patient most often reports pain originating from the anterosuperior aspect of the shoulder. However, isolating the structure responsible for anterosuperior shoulder pain can be a diagnostic challenge because of the innervation of the AC joint and the superior aspect of the glenohumeral joint. The lateral pectoral nerve provides innervation to the anterior aspect of the AC joint and surrounding structures of the shoulder, whereas the suprascapular nerve provides innervation to the posterior aspect of the AC joint and other posterior structures of the shoulder. Gerber and colleagues evaluated patterns of pain and found that irritation to the AC joint produced pain over the AC joint, in the anterolateral neck, and in the region of the anterolateral deltoid. Irritation of the subacromial space produced pain in the region of the lateral acromion and the lateral deltoid muscle but did not produce pain in the neck or the trapezius region.

Diagnostic tests specific to the AC joints include the following techniques: cross-arm adduction test, active compression test, AC resisted extension test, the Paxino test, and the Hawkins-Kennedy sign. Of note, several of the AC-specific tests are more specific for AC arthrosis and distal clavicle osteolysis as opposed to unstable AC joint disease.

  • Cross-arm adduction test: This test is performed with the arm elevated to 90 degrees and then adducted across the chest with the elbow bent at approximately 90 degrees. The described motion causes compression across the AC joint, leading to pain. Of note, this motion can also produce pain in the posterior aspect of the shoulder that is associated with a tight posterior capsule or at the lateral aspect of the shoulder, which can be associated with rotator cuff pathology ( Fig. 60-7, A ).

    FIGURE 60-7

    A, The cross-arm adduction test is performed with the arm flexed to 90 degrees in adduction across the body with a finger placed on the acromioclavicular (AC) joint, indicating pain at that spot only. It is important to understand that this test may produce pain posteriorly if a tight posterior capsule is decreasing internal rotation or in the glenohumeral joint if glenohumeral arthritis is present. This test is positive for AC joint disease only if cross-arm adduction produces pain at the AC joint itself. B and C, The O’Brien test is performed with the arm flexed to 90 degrees with the elbow in extension and adducted 10 to 15 degrees with maximal supination; it is then performed again in maximal pronation. Symptoms referred to the AC joint with either of these maneuvers or with the arm in supination indicate more of an AC joint disorder, whereas symptoms referred to the anterior glenohumeral joint that are increased in maximal pronation indicate more of a superior labral disorder.

  • Active compression test (O’Brien test): This test is performed with the arm elevated to 90 degrees and adducted to 10 to 15 degrees with the elbow in extension, followed by maximal pronation of the forearm with obligate internal rotation of the arm as the examiner applies a downward force resisted by the patient. The described positioning of the shoulder causes the greater tuberosity of the humerus to elevate the depressed acromion with the addition of applied resistance resulting in a “lock and load” of the AC joint. Symptoms referred to the top of the shoulder and confirmed by examiner palpation of the AC joint indicate damage to this structure, whereas symptoms referred to the anterior glenohumeral joint suggest labral or biceps disease. Therefore this test can be useful in differentiating AC joint disease from intraarticular disease ( Fig. 60-7, B and C ) .

  • AC resisted extension test: This test is performed with the arm flexed to 90 degrees and the elbow bent to 90 degrees. The patient is asked to extend the arm against resistance, and the test is positive if pain is reproduced in the area of the AC joint.

  • Paxino test: To perform this test the examiner places thumb pressure at the posterior AC joint in an attempt to cause reproducible pain.

  • Hawkins-Kennedy sign: This test was originally described with regard to the diagnosis of impingement syndrome by causing pain with forced passive internal rotation behind the back and forced adduction with internal rotation. Because impingement syndrome can lead to involvement of the AC joint, the maneuver has been shown to reproduce AC joint-related pain.

Overall, the clinical diagnosis of AC joint disease after a traumatic event can be determined via a triad of (1) point tenderness to palpation at the AC joint, (2) pain at the AC joint with cross-arm adduction, and (3) relief of symptoms by injection of a local anesthetic agent. Meanwhile, diagnosis of AC joint pathology resulting from nontraumatic or chronic overuse can often be accomplished via the cross-arm adduction test, active compression test, and AC resisted extension test. Chronopoulus et al. found that the AC resisted extension test combined with the cross-arm adduction test had the greatest sensitivity, whereas the active compression test had the greatest specificity and highest overall accuracy for diagnosis of these injuries.

Physical examination can help differentiate the different types of AC joint injuries ( Table 60-2 ). For example, type III injuries can often be distinguished from type V injuries by having the patient shrug both shoulders. Type III injuries are reducible with a shoulder shrug because the integrity of the deltotrapezial fascia has not been compromised.

TABLE 60-2


Type AC Ligament Injury CC Ligament Injury Deltotrapezial fascia Clinical Findings Radiographic Findings
I Intact Intact Intact AC tenderness Normal
II Ruptured Intact Intact Pain with motion; the clavicle is unstable in the horizontal plane The lateral end of the clavicle is slightly elevated; stress views show <100% separation
III Ruptured Ruptured Mild injury The clavicle is unstable in both the horizontal and vertical planes, the extremity is adducted, and the acromion is depressed relative to the clavicle Plain films and stress radiographs are abnormal—100% separation; in reality, the acromion and upper extremity are displaced inferior to the lateral clavicle
IV Ruptured Ruptured Injured as the clavicle is posteriorly displaced Possible skin tenting and posterior fullness The clavicle is displaced posteriorly on the axillary view
V Ruptured Ruptured Injured and stripped off the clavicle A more severe type III injury, shoulder with severe droop; if a shoulder shrug does not reduce it, then it is a type V injury A 100% to 300% increase in the clavicle to acromion distance
VI Ruptured Ruptured Possible injury Rare inferior dislocation of the distal clavicle; accompanied by other severe injuries; transient paresthesias The clavicle is lodged behind the intact conjoined tendon

AC, Acromioclavicular; CC, coracoclavicular.


Radiographic evaluation of the AC joint typically requires one third to half of the radiographic penetration that is generally required for the denser glenohumeral joint, which is why in a standard anteroposterior (AP) view of the shoulder, the AC joint is overpenetrated (dark) and small problems or subtle disease may be overlooked. A plain radiographic workup of AC joint disease should include standard AP, lateral, and axillary views of the shoulder; specialized views that are more helpful in identifying AC joint pathology include the Zanca view, Basmania view, stress view, and Stryker notch view.

Although the standard AP view of the shoulder is not specific to the AC joint, this view does permit evaluation of vertical CC translation. The normal anatomic CC interspace is approximately 1.1 to 1.3 cm, although this interval does exhibit variability, as demonstrated by Bosworth. Bearden et al. cites a 25% to 50% increase of the CC interval compared with the contralateral shoulder as indicative of complete CC disruption. The axillary view of the shoulder can be helpful in evaluating type IV injuries with a posteriorly displaced distal clavicle.

The Zanca view is the most accurate plain film assessment of AC joint pathology. This view is performed by tilting the radiologic beam 10 to 15 degrees toward the head and using only 50% of the standard shoulder AP penetration strength, which is optimal in delineating the AC joint. As determined by Zanca, the normal AC joint width is between 1 and 3 mm, although this width diminishes with age ( Fig. 60-8 ).


An explanation of why the acromioclavicular (AC) joint is poorly visualized on routine shoulder radiographs. A, This routine anteroposterior view of the shoulder shows the glenohumeral joint well. The AC joint is too dark to be interpreted, however, because that area of the anatomy has been overpenetrated by the x-rays. B, When the usual exposure for the shoulder films is decreased by two thirds, the AC joint is well visualized. The inferior corner of the AC joint, however, is superimposed on the acromion process. C, Tilting the tube 15 degrees upward provides a clear view of the AC joint. D, The position of the patient for the Zanca view: a 10- to 15-degree cephalic tilt of the x-ray tube is required to visualize the AC joint.

(From Rockwood CA Jr, Williams GR Jr, Young DC: Disorders of the acromioclavicular joint. In Rockwood CA Jr, Matsen FA III, Wirth MA, et al, editors: The shoulder, ed 3, Philadelphia, 2004, Elsevier.)

The Basmania view is a cross-arm adduction view, taken with the arm elevated to 90 degrees and adducted across the body. This view is helpful in showing unstable AC joint injuries if the clavicle is found to override the position of the acromion.

The stress view of the AC joint is obtained by placing 5 lb on each wrist and essentially taking an AP view of both shoulders and is mainly used to differentiate between type II and III dislocations. Patients who present with a clinically obvious AC injury and deformities suggestive of complete dislocation (types III, IV, V, and VI) often demonstrate maximal CC interspace widening on routine AP view and thus do not require stress views ( Fig. 60-9 ).


The technique of obtaining stress radiographs of the acromioclavicular (AC) joint. A, Anteroposterior radiographs are made of both AC joints with 10 to 15 lb of weight hanging from the wrists. B, The distance between the superior aspect of the coracoid and the undersurface of the clavicle is measured to determine whether the coracoclavicular ligaments have been disrupted. One large horizontally positioned 14- by 17-inch x-ray cassette can be used in small patients to visualize both shoulders on the same film. In large patients, it is better to use two horizontally placed smaller cassettes and take two separate films to obtain the measurement. The arrows indicate the inferior subluxation of the scapulohumeral complex.

(From Rockwood CA Jr, Williams GR Jr, Young DC: Disorders of the acromioclavicular joint. In Rockwood CA Jr, Matsen FA III, Wirth MA, et al, editors: The shoulder, ed 3, Philadelphia, 2004, Elsevier.)

The Stryker notch view is helpful in evaluating patients in whom the clinical suspicion for AC joint dislocation is high despite a normal CC interval on the standard AP view of the shoulder ( Fig. 60-10 ). This view helps visualize a coracoid fracture, which should be suspected in the case of a normal CC interspace with complete AC disruption. This view is taken with the patient supine with his or her palm (affected side) placed on his or her head and the beam titled 10 degrees cephalad.

FIGURE 60-10

The Stryker notch view.

Decision-Making Principles

Treatment options for AC joint injuries are continuously evolving ( Table 60-3 ). The overall goal, regardless of injury severity, is to regain pain-free movement with full and stable range of motion. Initially nonoperative treatment (i.e., use of a sling, ice, analgesics, and immobilization) should be attempted for all patients with incomplete (types I and II) AC joint injuries. Although no current evidence supports the recommendation of surgical intervention for type I or II injuries, some studies have demonstrated persistent symptoms years after nonoperative treatment.

TABLE 60-3


Treatment Classification Essentials of Repair Clinical and Operative Considerations Level of Evidence
AC ligament repair The AC ligament is repaired with reinforcing pin(s), screw, or plate The implant is usually removed IV
Dynamic muscle transfer Transfer of the short head of the biceps with or without coracobrachialis Partial transfer of structures—may alter shoulder mechanics IV
CA ligament transfer Transfer of CA ligament alone or in concert with other procedures Preserve the length of the CA ligament IV
CC ligament repair Traditionally the Bosworth screw technique—wires, suture loops, and grafts have been described Usually requires a second procedure for hardware removal IV
Distal clavicle resection with CC reconstruction Classically, the distal clavicle is excised and the CC is reconstructed using CA ligament Can also be a salvage procedure for persistent pain after an AC dislocation (especially for type I and II injuries) IV
Distal clavicle resection without CC reconstruction IV
Arthroscopic repair and reconstruction Repair or reconstruction arthroscopically viewed from the subacromial space of CC ligaments Technical reports have described the efficacy of the procedure VI
Anatomic reconstruction of the CC ligaments Reconstruction of CC ligaments using soft tissue grafts to reapproximate the conoid and trapezoid ligaments Potential advantages of improved horizontal plane stability IV

AC, Acromioclavicular, CA, coracoacromial; CC, coracoclavicular.

For patients with complete AC joint injuries (i.e., types IV, V, and VI), treatment is typically operative because of the significant morbidity associated with persistently dislocated joints and severe soft tissue disruption. In the randomized controlled trial of 12 patients with type V AC joint dislocations, Bannister and colleagues demonstrated superior results with operative treatment with CC screw and AC joint fixation compared with nonoperative treatment.

Treatment of type III injuries remains controversial, with a trend toward initial nonoperative treatment in most cases. Factors involved in the decision-making process include activity level, type of sport/work, timing of injury with regard to athletic season, and throwing demands on both the injured and contralateral shoulder. A basic algorithm has been proposed with regard to high-level athletes with type III injuries. If the athlete is currently in the midst of his or her playing season, then consideration of an intraarticular injection and return to sport may be considered. If the athlete is not in the midst of his or her playing season, then he or she should undergo functional rehabilitation for up to 3 months followed by either return to full activity (if asymptomatic) or consideration of surgery (if symptomatic). Evidence supporting nonoperative treatment of type III AC dislocations has been provided by a metaanalysis performed by Phillips and colleagues, in which 88% of operatively treated patients and 87% of nonoperatively treated patients (a total of 1172 patients) had satisfactory outcomes. Complications included the need for further surgery (59% operative vs. 6% nonoperative), infection (6% vs. 1%), and deformity (3% vs. 37%). Pain and range of motion were not significantly affected regardless of the treatment choice. Overall, based on the available evidence, the authors did not recommend surgery for type III AC joint injuries in young patients.

McFarland and associates published the results of a survey of Major League Baseball team physicians evaluating treatment modalities for a type III injury in a pitcher. Sixty-nine percent of the respondents reported that they would opt for nonoperative treatment. Of the 32 patients with type III injuries, 20 were treated nonoperatively and 12 were treated operatively. Complete pain relief and normal function was achieved in 80% of the patients treated nonoperatively and in 91% of the patients treated operatively. A recent survey of American Orthopaedic Society for Sports Medicine members indicated that 86% of respondents preferred nonoperative treatment for their patients with type III injuries.

Treatment Options

As mentioned in the preceding section, most type I and type II AC joint separations are treated in a nonoperative fashion, and type III injuries are usually evaluated on a case-by-case basis, taking into account hand dominance, occupation, whether heavy labor is performed, position/sport requirements (e.g., quarterbacks and pitchers), scapulothoracic dysfunction, and a risk for reinjury. Patients with types IV, V, and VI are generally treated operatively. Some literature information supports reduction of the clavicle in type IV, V, and VI injuries, turning them into a type III injury and then treating them conservatively. Certainly, higher level studies are needed before a gold standard treatment algorithm for type III injuries can be provided.

The main goals of treatment, whether surgical or nonsurgical, are to achieve a pain-free shoulder with full range of motion, strength, and no limitations in activities. The demands on the shoulder will differ from patient to patient, and these demands should be taken into account during the initial evaluation.

General nonoperative treatment involves the use of a sling with ice and antiinflammatory agents, as well as a brief period of immobilization typically lasting 3 to 7 days. The use of the sling is recommended until the pain has subsided, which typically takes 1 to 2 weeks for type I injuries and upward of 3 weeks for type II injuries. Prior to return to athletic activity, a four-phase rehabilitation protocol has been described by Gladstone and colleagues, including (1) pain control, immediate protective range of motion, and isometric exercises; (2) strengthening exercises using isotonic contractions; (3) unrestricted functional participation with the goal of increasing strength, power, endurance, and neuromuscular control; and (4) return to activity with sports-specific functional drills (see Figs. 60-11 to 60-14 ).

  • Phase 1: The first phase of nonoperative treatment ( Fig. 60-11 ) is to decrease pain, thus allowing early range of motion to nourish the cartilage and maintain maximal soft tissue function. Ice and some short-term immobilization can be used in this phase to decrease pain and reduce inflammation. Active-assisted range of motion is begun as early as possible for shoulder internal-external rotation and elevation-depression of the arm in the plane of the scapula (30 to 45 degrees of abduction and 30 to 40 degrees of forward flexion). It is important for the patient to reach the range of motion where pain begins but not go beyond this point. Arm elevation in abduction allows the clavicle to rotate upward, which stresses the AC ligament and can further increase pain and inflammation, and thus the athlete is instructed not to perform this motion. Other motions to decrease the atrophy of the surrounding muscular groups in the shoulder are shoulder flexion and internal and external rotation. These exercises are performed in an isometric fashion so as not to cause the clavicle to rotate. The patient or athlete is transitioned to the second phase when the range of motion and forward elevation are relatively pain free or with minimal pain up to 140 degrees of flexion and maximal external rotation compared with the contralateral arm. The criteria to advance to phase 2 are (1) 75% of full range of motion, (2) minimal pain and tenderness on palpation of the AC joint, and (3) a manual muscle test grade of 4 out of 5 for the anterior deltoid, middle deltoid, and upper trapezius.

  • Phase 2: The main goal of phase 2 ( Fig. 60-12 ) is to help a patient advance to full painless range of motion and increase strength in an isotonic arc. Active-assisted motion exercises, allowing up to full forward flexion and internal and external rotation, are performed with 90 degrees of shoulder abduction, as well as with the arm at the patient’s side. Strengthening exercises are directed toward the deltoid, trapezius, and rotator cuff. Press maneuvers such as the bench press or the military shoulder press are limited because they increase the stress in the AC joint. The criteria for advancing from phase 2 to phase 3 are a nonpainful range of motion, no pain or tenderness on palpation, and strength that is 75% that of the contralateral side.

  • Phase 3: The main goal of phase 3 ( Fig. 60-13 ) is to increase the strength of the entire shoulder complex musculature. Specific exercises emphasized during this phase are isotonic dumbbell shoulder flexion, abduction, shrugs, and bench press ( Fig. 60-14 ).

  • Phase 4: Transition to phase 4, which involves sport-specific exercises, is allowed when the patient achieves (1) full range of the motion, (2) no pain or tenderness, (3) satisfactory clinical examination, and (4) isokinetic test data with close to 100% of strength and range of motion compared with the contralateral uninjured side (if available). These isokinetic tests are performed at 180 degrees per second and 300 degrees per second (see Fig. 60-14 ) .

FIGURE 60-11

Phase 1: Nonoperative treatment. Active-assisted range of motion for external rotation.

FIGURE 60-12

Phase 2: The patient advances to active-assisted motion exercises that allow up to full forward flexion. Internal and external rotation is performed with 90 degrees of shoulder abduction, as well as with the arm at the patient’s side. The T bar is used for active-assisted range of motion, allowing the patient to participate in his or her care.

FIGURE 60-13

Phase 3: Increased strength and endurance of both the scapula stabilizers and specific rotator cuff muscles are attained using Thera-Bands and isometrics.

FIGURE 60-14

Phase 4: The last rehabilitative stage involves sport-specific exercise and permits throwing.

Despite the prevalence and the success of nonoperative management of AC joint injuries, much of the literature has focused on surgical treatment. Operative treatment of types IV, V, and VI is generally recommended because of morbidity associated with persistent marked displacement of the distal clavicle, although good results with conservative management have been reported. A closed reduction maneuver should be attempted because these types of dislocations can sometimes be reduced into a position that mimics a type III injury, then treated nonoperatively.

The literature is replete with surgical techniques to address complete AC dislocations, with more than 75 different techniques described in various reports. The majority of all techniques are based on several basic types of procedures, including (1) primary AC joint fixation with pins, screws, or rods; (2) coracoacromial ligament transfer (Weaver-Dunn) ± distal clavicle excision; (3) anatomic CC reconstruction; and (4) arthroscopic suture fixation. Nearly all of the recently reported “novel” techniques involve combinations of the basic techniques, modifications of these techniques, and/or modifications of the modifications.

In addition to primary repair, these procedures can include reconstruction augmentation with autogenous tissue (coracoacromial ligament), augmentation with absorbable and nonabsorbable suture and prosthetic material, and CC stabilization with metallic screws. The Weaver-Dunn technique using transfer of the coracoacromial ligament has been the most popular procedure in acute and chronic injuries. Several more recent reports have described good results with modifications of the Weaver-Dunn technique. However, compromised results have been observed in patients after Weaver-Dunn–based procedures with residual subluxation or dislocation after surgery. Ammon and associates performed a biomechanical study comparing the Bosworth screw with a poly-L-lactic acid bioabsorbable screw and found that the Bosworth screw provided superior strength (native ligament, 340 N; poly-L-lactic acid screw, 272 N; and Bosworth screw, 367 N).

From a biomechanical perspective, the importance of the CC ligaments and AC ligaments in controlling superior and horizontal translations has been elucidated. In fact, failure to surgically reproduce the conoid, trapezoid, and AC ligament function with current techniques may explain the observed incidence of recurrent instability and pain. Several authors have advocated using a separate and potentially more robust graft source to improve surgical results. The use of a free autogenous or allograft tendon has been further supported biomechanically. Other reconstruction grafts, such as the lateral half of the conjoined tendon, have also been described. Anatomic reconstruction of the CC ligaments has been shown to be biomechanically superior when compared with previous surgical constructs. Other types of fixation have been biomechanically evaluated, including interference screw fixation, suture cerclage, and suture anchors. Although none of these techniques fully restored native AC joint stability, they were all found to be superior to the Weaver-Dunn procedure. Thus given the biomechanical limitations of CA ligament transfer, newer techniques involve augmentation with CC ligament reconstruction using tendon grafts, suture anchors, screws, or suture loops.

The major surgical options for AC joint reconstruction are included in the following summary:

  • Primary AC joint repair involves primary repair of the AC ligament with reinforcement of the superior AC ligament with joint meniscus. The repair is typically augmented with smooth or threaded pins, screws, suture wires, or plates (e.g., an AC joint plate or hook plate). This technique features limited surgical dissection; however, it places the patient at risk for pin migration ( Fig. 60-15 ) .

    FIGURE 60-15

    Acromioclavicular ligament repair. The acromioclavicular joint is fixed internally with two unthreaded Kirschner wires. The wires are generally removed about 8 weeks after surgery.

    (From Justis EJ Jr: Traumatic disorders. In Canale ST, editor: Campbell’s operative orthopedics, vol 3, ed 7, St Louis, 1987, Mosby.)

  • Coracoacromial ligament transfer (Weaver-Dunn) with or without distal clavicle excision involves transfer of the coracoacromial ligament from the acromion to the clavicle as a substitute for the ruptured CC ligament with or without distal clavicle excision ( Fig. 60-16 ) .

    • Debate exists regarding distal clavicle excision:

      • If the patient’s condition is very acute, if AC joint arthrosis is minimal, and/or if stability is of paramount concern, one may consider keeping the distal clavicle, especially because recent biomechanic evidence has suggested increases in horizontal translation with sequential resection.

      • If the patient has a chronic injury or preexisting AC joint arthrosis, consideration of excision should be recommended.

    • Modification to the Weaver-Dunn procedure includes transfer of the conjoined tendon to the distal clavicle, augmentation with a suture loop, and augmentation with a semitendinosus autograft or anterior tibialis allograft via a bone tunnel and interference screw fixation.

    FIGURE 60-16

    Dr. Charles Rockwood’s method of reconstructing a chronic type III, IV, V, or VI acromioclavicular dislocation. A, The incision is made in Langer’s lines. B, The distal end of the clavicle is excised. C, The medullary canal is drilled out and curetted to receive the transferred coracoacromial ligament. D, Two small drill holes are made through the superior cortex of the distal clavicle. The coracoacromial ligament is carefully detached from the acromion process. E, With the coracoacromial ligament detached from the acromion, a heavy nonabsorbable suture is woven through the ligament. F, The ends of the suture are passed out through the two small drill holes in the distal end of the clavicle. The coracoclavicular lag screw is inserted, and when the clavicle is reduced to its normal position, the sutures used to pull the ligament snugly up into the canal are tied.

    (From Rockwood CA Jr, Williams GR Jr, Young DC: Disorders of the acromioclavicular joint. In Rockwood CA Jr, Matsen FA III, Wirth MA, et al, editors: The shoulder, ed 3, Philadelphia, 2004, Elsevier.)

  • Anatomic CC reconstruction involves arthroscopy, distal clavicle excision, and reconstruction with an autograft or allograft. Biomechanically, this technique has been shown to better reapproximate the stiffness of the native CC ligament complex and improve anterior and posterior translation restriction compared with the Weaver-Dunn procedure and is described in detail in the Authors’ Preferred Technique section.

  • Arthroscopic suture fixation involves restoration of the CC ligaments arthroscopically using two suture anchors through four drill holes in the clavicle with an associated CC ligament transfer. The suture anchors are thus fixed to the coracoid as the suture is tied over a bone bridge to the clavicle. Similarly, tightrope devices have been used as well; this technique is also arthroscopic and involves two single tunnels through the clavicle and coracoid in which to feed the tightrope device.

Authors’ Preferred Technique

Anatomic Coracoclavicular Reconstruction


  • A curvilinear center incision is placed roughly 3.5 cm from the distal clavicle or AC joint, along Langer’s lines toward the coracoid process ( Figs. 60-17 and 60-18 ).

    • Control of superficial skin bleeders down to the fascia of the deltoid is accomplished with a needle-tip bovie.

    • Once the entire clavicle is palpated, full-thickness flaps are made from the midline of the clavicle both posteriorly and anteriorly, skeletonizing the clavicle; this is done in the area of the CC ligament.

    FIGURE 60-17

    Initial exposure for access to the acromioclavicular joint. The skin incision is made in line with Langer’s lines, from anterior to posterior. Once the deltotrapezial fascia is encountered, this layer is incised sharply over the midline to develop full-thickness fascial flaps in a medial to lateral direction. Repair of this layer during closure is an important aspect of the case.

    FIGURE 60-18

    Distances for the distal clavicle excision and bone tunnels are shown. The conoid bone tunnel should start about 45 mm from the acromioclavicular joint, in the posterior one third of the clavicle. The trapezoid bone tunnel should be positioned 15 mm anteromedial to the conoid bone tunnel.

Distal Clavicle Excision

  • When the joint is diseased or the patient has a history of arthrosis, the preference is to leave the distal clavicle intact.

  • If necessary, only a small amount (a small sliver) of up to 3 to 5 mm of distal clavicle is removed with the use of a sagittal saw and rasp ( Fig. 60-19 ).

    FIGURE 60-19

    If the distal clavicle is excised, care is taken to ensure that the posterior aspect of the distal clavicle is beveled, using the small sagittal saw and a rasp, to avoid posterior abutment.

Graft Preparation

  • Selection depends on the surgeon’s preference.

  • A semitendinosus autograft or allograft or anterior tibialis allograft can be used ( Fig. 60-20 ).

    FIGURE 60-20

    Graft preparation. Here a tibialis anterior allograft is used, and the two ends of the tendon are stitched in Krakow fashion using No. 2 FiberWire (Arthrex). The graft is then doubled over and measured using graft sizers from the Biotenodesis System (Arthrex). The doubled-over graft size is usually 6 to 7 mm. If larger, the graft should be trimmed (especially in an allograft situation). The graft is then placed under tension on the back table in preparation for implantation.

Coracoid Fixation

  • A bone tunnel interference screw fixation or loop technique is used.

Bone Tunnel Interference Screw Fixation Technique

  • The graft is folded in its middle, and a high-strength suture (No. 2 FiberWire, Arthrex) or a No. 2 nonabsorbable suture is placed through the doubled-over tendon graft in a Krakow manner.

  • One to two Krakow sutures are placed in the remaining two free ends of the graft.

  • The graft is placed on the table in a moist sponge until the bone tunnels are prepared.

  • Bone tunnel preparation in the coracoid: The diameter of the doubled-over portion of the graft is measured with a standard tendon-measuring device or using the handle of a repair system (Biotenodesis System, Arthrex) to determine the graft size (see Fig. 60-20 ).

  • The appropriate cannulated reamer is chosen (usually, 6 or 7 mm).

  • Finger palpation of both the lateral and medial portions of the coracoid process and drilling into the coracoid base under direct visualization with a cannulated reamer guide pin is completed.

    • A coracoid drilling guide (Arthrex) can also be used to act as a pipe-fitting device, fitting over the base of the coracoid process and placing the surgeon in the correct position to insert the pin.

    • When the guide pin has been inserted and it has been confirmed by digital palpation that it is not out of the coracoid process, the cannulated reamer of the specific graft size is used and the coracoid is reamed to a depth of 15 to 17 mm.

  • Copious irrigation is used to remove any excess bone shavings from the reaming.

  • The driver is assembled, and a 5.5 × 15 mm bioabsorbable or inert (polyetheretherketone [PEEK]) screw is placed on the end.

  • A nitinol wire is placed through the center cannulation of the screwdriver and used to shuttle the suture from the graft through the driver.

  • The long end of the Krakow suture attached to the graft should be placed through the cannulated portion of the Biotenodesis driver.

  • The tenodesis driver is advanced to touch the tendon graft, and the entire tendon, driver, and screw complex is placed into the coracoid bone tunnel ( Fig. 60-21 ) . The Krakow suture, usually measured to be about 15 mm in length and running up and down the doubled portion of the tendon graft, should disappear from view when the tendon, driver, and screw complex is placed into the coracoid bone tunnel.

Feb 25, 2019 | Posted by in SPORT MEDICINE | Comments Off on Injury to the Acromioclavicular and Sternoclavicular Joints
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