Management of Acromioclavicular Joint Injuries: Acute and Chronic

The Problem

Acromioclavicular (AC) injuries are very common in contact sports (rugby, wrestling, ice hockey, and football) and the majority of these injuries are in the form of sprains. The common mechanism of AC joint separation involves a direct trauma to the posterosuperior part of the shoulder or an indirect mechanism via a fall on an outstretched adducted arm or elbow, which drives the humeral head into the AC joint. The AC joint injury involves disruption of the AC ligaments, with complete dislocations involving injury to the coracoclavicular (CC) ligaments, the deltoid, and trapezial muscles and fascia. The ideal operative technique for the management of high-grade AC injuries and the ideal graft choice for AC joint reconstruction (autograft, allograft, or synthetic graft) is a matter of ongoing debate. The management of type III AC joint separation is another area of controversy and there is no uniform consensus on operative versus non-operative management.

Clinical Presentation

Patients with acute AC joint injury present with pain, swelling, occasional ecchymosis, and bruising based on the mechanism of injury. Pain and/or deformity are the two principal presentations of sub-acute and chronic AC joint instability. Pain in the trapezius region and the anterolateral deltoid is more specific for AC joint injury, whereas pain located only in the lateral deltoid is more indicative of a subacromial process. Mechanism of injury provides an important cue for AC joint injury. The deformity associated with the AC joint separation is due to inferior translation of the scapulohumeral complex resulting in prominence of the lateral end of clavicle.

Classic history

Direct trauma on the point of the shoulder (superior aspect) during contact sports or a fall and presence of pain in the AC region with or without deformity.

Diagnostic Workup

Classic physical exam findings

Patients should be preferably examined in a seated position with the arm freely hanging by the side. Patients with acute AC joint injury are tender to palpation overlying the AC joint and may have swelling and ecchymosis depending on the severity of injury. Deformity associated with the AC joint separation is due to inferior translation of the scapulohumeral complex resulting in prominence of the lateral end of the clavicle. The patient can reduce this deformity by shrugging their shoulder. If the lateral end of the clavicle is buttonholed through the trapezial fascia, the shrugging maneuver may not result in reduction of the deformity.

A triad of point tenderness at the AC joint, worsening of pain at the AC joint with cross-arm adduction, and relief of symptoms by injection of a local anesthetic into the AC joint is diagnostic for AC joint injury and particularly useful when there is no deformity. The Paxinos test and O’Brien test are sensitive tests to confirm AC joint pathology. In a positive Paxinos test tenderness or pain is present in the AC joint region when the examiner applies pressure to the acromion and midpart of the clavicle in opposite directions in an attempt to stress the AC joint (anterosuperior direction for the acromion and inferiorly to the midpart of the clavicular shaft.

During the O’Brien active compression test, the affected shoulder is flexed to 90 degrees, adducted to 10-15 degrees, and internally rotated with the elbow in full extension. A downward force is applied with the palm facing down (pronation) and the maneuver is then repeated with the palm facing up (supination). The examiner must confirm that the pain is on the “top of the shoulder” and not front of the shoulder and that the pain is relieved by supination. The sternoclavicular joint should be examined and a complete neurovascular examination should be performed.

Imaging findings

Radiographic examination of the AC joint includes the anteroposterior (AP) view of the clavicle, the axillary and supraspinatus outlet view of the shoulder and the Zanca view. A bilateral Zanca view is made by tilting the x-ray beam 10-15 degrees toward the cephalic direction. Widening of the AC joint, step off deformity at the AC joint, and increase in the CC distance (common range 1.1-1.3 cm) are indicative of AC joint injury (Figure 1). Increase of CC distance of 25-50% over the normal side on a bilateral Zanca view indicates complete CC ligament disruption. An axillary view of the shoulder is helpful in differentiating a posterior translation versus superior translation of the clavicle in relation to the acromion. A Stryker notch view and axillary view provides a non-superimposed image of the coracoid process and is useful if a coracoid process fracture is suspected (normal CC distance in conjunction with a complete dislocation of the AC joint). The stress AP views (5-10 lbs laced in the ipsilateral hand) of the AC joint are of historical practice and are seldom necessary.

Figure 1.

Bilateral Zanca view demonstrating AC joint dislocation (black arrow) and increased CC distance on the right side compared to the left side (red arrow).

Non–Operative Management

The main goals of treatment are to achieve a pain-free shoulder with full range of motion and strength and no limitations in activity.

Treatment begins with a sling, ice, and a brief period of immobilization only for pain control followed by rehabilitation as soon as tolerated. The rehabilitation program consists of four phases:

  • Pain control, immediate protective range of motion, and isometric exercises.

  • Strengthening exercises using isotonic contraction.

  • Unrestricted functional participation with the goal of increasing strength, power, endurance, and neuromuscular control.

  • Return to activity with sports-specific functional drills.

The majority of type I and type II AC joint injuries are treated non-operatively and they do very well. The treatment of type III injuries is controversial and a matter of ongoing debate. Patients with Type III injuries are usually evaluated on a case-by-case basis, taking into account variables like hand dominance, occupation, heavy labor, position, and sport requirements (quarterbacks, pitchers), scapulothoracic dysfunction, and risk for re-injury. One approach for the management of type III AC joint separation is to treat these injuries conservatively and consider surgical stabilization if there is persistent pain, scapular dyskinesia, or weakness and fatigue with the use of injured arm. In an alternative approach, a type III AC joint separation can be treated surgically if they fail a brief trial of conservative management especially in athletes and high-demand patients to allow quicker return to work or play and to limit the duration of painful disability.

In an athlete multiple factors are considered during decision making of operative versus non-operative treatment of Type III dislocations and this includes type of sport (contact versus overhead), level of participation (recreation versus competitive), sports type (baseball, basketball, football, hockey, volleyball etc), and if the athlete is off season versus in season. All athletes with type III injures are given a 3-week trial of non-operative management and if they demonstrate improved pain control and increased use of their arm they are allowed to return back to sports especially if they are in competitive season. If the athlete demonstrates no or minimal improvement with a trial of non-operative management, a discussion is had with the athlete about operative management. We recommend surgery to patients with high-grade dislocations (Types IV, V and VI).

Indications for Surgery

Indications for surgery:

  • Type IV, V and, VI AC joint separations.

  • Type III AC joint separation in a high demand individual (athlete) or in a patient that failed conservative management.

Multiple different operative techniques for the surgical management of AC joint separation have been described in literature. Both arthroscopic and open techniques are available and can be broadly categorized as:

  • AC joint stabilization using hook plates, pins, or K-wires.

  • CC space stabilization using suture or tape, screw, cortical button, suture anchor, and other similar devices.

  • Ligament reconstruction: CC ligament and/or AC ligament reconstruction using autograft or allograft.

  • Dynamic muscle transfer (proximally-based conjoint tendon transfer).

Surgical Technique

Anatomic coracoclavicular ligament reconstruction

Anatomic coracoclavicular ligament reconstruction (ACCR) attempts to reconstruct the anatomy and biomechanics of the AC joint and CC space. ACCR can be performed via an open or arthroscopic approach. Open ACCR has been extensively studied in our biomechanics laboratory and is our procedure of choice and is described in detail here.

Necessary Equipment/Instrumentation
  • Standard OR table

  • Mini-C arm

  • ACCR instrumentation set

  • Allograft (Peroneus longus)

  • Graft preparation board

  • No. 2 Collagen coated FibreWires

  • PEEK suture anchors (5.5)

  • Hewson suture passer

  • Pointed reduction forceps

Patient Positioning
  • The patient is placed in a beach-chair position after induction of general anesthesia (Figure 2).

  • A small bump is placed on the medial scapular edge to stabilize it and elevate the coracoid anteriorly.

  • The head is safely and firmly secured but should not be taped because repositioning is sometimes necessary during medial clavicle drilling.

  • Wide draping is done to include the sternoclavicular joint and posterior clavicle for complete visualization of the shoulder girdle.

  • The arm is free draped to allow free motion and maneuvers to reduce the AC joint.

  • A mini C-arm image of the AC joint should be obtained to ensure feasibility of accurate imaging intraoperatively.

Figure 2.

Patient positioning. Beach chair position with head tilted to the opposite side and a bump under the scapula to elevate the coracoid anteriorly.


Anatomic Coracoclavicular Ligament Reconstruction

In the ACCR, autograft or allograft tendon tissue is used to reconstruct the conoid and trapezoid ligaments with reinforcement of the AC joint capsular ligaments. In open ACCR, the fixation of the graft on the clavicle is performed using interference screws. The fixation of the graft on the coracoid can be performed either by looping the graft around the coracoid base (loop technique is our preferred technique) or by using an interference screw (tenodesis technique). A collagen-coated FibreWire is also incorporated along with the graft around the coracoid base and through the bone tunnels. The graft provides a biological form of fixation and collagen-coated FibreWire provides the non-biologic form of fixation. Arthroscopy of the glenohumeral joint can be performed if there is concern for intra-articular injury.

Surgical Exposure

(Figure 3)

Figure 3.

Surgical exposure. The deltotrapezial fascia is tagged with sutures and fascioperiosteal flaps are elevated on either side of the clavicle to get a circumferential exposure of the distal clavicle.

  • A curvilinear skin incision centered ~3 cm medial to the AC joint is made starting more lateral at the posterior clavicle and gently angled towards the coracoid process along the Langer’s lines.

  • Full thickness cutaneous flaps are elevated to expose the underlying deltotrapezial fascia.

  • Deltotrapezial fascioperiosteal flaps are elevated from the midline of the clavicle both posteriorly and anteriorly to expose the lateral end of the clavicle circumferentially and the AC joint laterally. The deltoid muscle should be elevated in its entirety on the clavicle without damaging its origin. It is important to note the anterior deltoid takes origin from the superior, anterior, and anterioinferior surface of the clavicle.

  • Tagging sutures are placed in the deltotrapezial fascia during the approach for retraction and later to allow for effective closure.

Graft Preparation

(Figure 4)

Figure 4.

Graft preparation and sizing of the graft.

  • An allograft (peroneus longus) or autograft (semitendinosus) can be used for this procedure.

  • A whipstitch or grasping suture is placed in the two free ends of the tendon for passage through the bone tunnels. The tendon is sized using standard tendon sizers (usually 5 mm).

  • Tendon ends are bulleted for easy passage through bone tunnels.

Coracoid Preparation

(Figure 5, Figure 6)

Figure 5.

Figure 5. Suture passing device for passing suture around the coracoid.

Figure 6.

Suture passing device is used from the medial to lateral direction around the coracoid to pass a suture, which is used to shuttle the graft and FibreWire around the coracoid.

  • The graft can be fixed to the coracoid by either looping the graft around the base of the coracoid (Loop technique) or by the tenodesis of the graft into the base of coracoid with the use of an interference screw (Tenodesis technique).

  • Soft tissue dissection is performed to expose the coracoid process including the medial and lateral margins.

  • An aortic cross-clamp (Stanitski clamp) or a suture-passing device is then passed in a medial to lateral direction and a suture is fed around the base of the coracoid.

  • A loop is created at one end of this suture and is used to pass the prepared graft, and a collagen coated no. 2 FibreWire around the base of the coracoid.

Clavicle Preparation

(Figure 7)

Figure 7.

Bone tunnels in clavicle. The conoid tunnel is usually drilled at a distance of ~50 mm from the AC joint and the trapezoid tunnel is drilled no less than 20-25 mm from the AC joint.

Bone tunnels are drilled in the clavicle for the reconstruction of the conoid and trapezoid ligament attachment on the clavicle. We have shown in our laboratory that the bone density decreases as we move more laterally on the distal clavicle and this can affect the fixation strength and graft pull out strength in a negative fashion. Therefore we drill our tunnels through the densest part of the lateral clavicle, which also happens to be the anatomic locations for the conoid and trapezoid ligaments.

  • To recreate the conoid ligament attachment on the clavicle, a guide pin is drilled approximately 45 mm medial from the distal end of the clavicle. Alternatively, the conoid tubercle on the inferior surface of the lateral third of clavicle can be used as an anatomic landmark for this guide pin placement.

  • The drill hole for the conoid ligament should be as posterior as possible, taking into account the space needed to prevent a “blow out” of the posterior cortical rim during subsequent reaming. A 5 mm cannulated reamer (depending on the size of the graft) is used on power to drill over the pin to create the tunnel.

  • After the bone tunnel has been drilled, we pull the reamer out manually to ensure that the tunnel is a perfect circle and not widened by uneven reaming. The depth of the tunnel is measured for appropriate screw length placement. A 5.5 tap is then used to tap the hole.

  • The same procedure is repeated for the trapezoid ligament, which is a more anterior and lateral structure compared to the conoid ligament. This tunnel is centered on the clavicle, approximately 15 mm lateral to the center portion of the previous tunnel but definitely 25-30 mm medial to the AC joint.

Graft Fixation to the Clavicle and Reconstruction of Coracoclavicular space and Acromioclavicular joint anatomy

(Figure 8, Figure 9, Figure 10, Figure 11, Figure 12, Figure 13, Figure 14)

Figure 8.

Graft is passed around the coracoid and through the bone tunnels in the clavicle along with the collagen coated FibreWire.

Figure 9.

Reduction of the AC joint and CC space with a pointed reduction forcep (one tine of the forcep is on the clavicle and the other tine is on the inferior surface of the coracoid).

Figure 10.

Fixation of the reconstructed conoid ligament in the clavicle using a PEEK interference screw while the AC joint is held reduced with a pointed reduction forceps.

Figure 11.

The AC joint reconstruction with the excess graft from the trapezoid tunnel.

Figure 12.

Closure of the deltotrapezial-periosteal flaps.

Figure 13.

Skin closure.

Figure 14.

Intra-operative radiographic image demonstrating reduction of the AC joint and restoration of the CC distance.

  • The limbs of the graft can be passed through the bone tunnels in a crossed (figure-of-eight) or a non-crossed fashion (“U loop”).

  • If there is predominant posterior displacement, we prefer a non-crossed graft through the tunnels and if there is superior displacement, a figure-of-eight configuration is used.

  • Each limb of the graft is accompanied by one of the two ends of a no. 2 collagen coated FibreWire, which when tied to itself will provide non-biologic augmentation of the repair.

  • After the grafts and collagen coated FibreWire has been passed through the bone tunnels, the AC joint is reduced by applying an upwards-directed force to the elbow or arm. A large pointed reduction forceps placed on the coracoid process and the clavicle is used to hold the reduction. Fluoroscopy is used to confirm adequate reduction of the AC joint.

The conoid part of the CC ligament is secured first. The graft is positioned so that the graft tail representing the conoid ligament is left 2 cm proud from the superior margin of the clavicle. The long tail of the graft exits the trapezoid tunnel and will later be used to augment the AC joint repair.

  • With traction placed on the graft, ensuring its tautness, a non-absorbable radiolucent screw of appropriate size and length is placed in the conoid tunnel. We prefer a 5.5 mm size PEEK screw.

  • While holding reduction and tension on the ligament, another non-absorbable radiolucent screw is placed in the lateral trapezoid tunnel anterior to the trapezoid ligament graft.

  • With both grafts secured, the no. 2 collagen coated FibreWire is tied over the top of the clavicle.

  • The pointed reduction forceps is removed and mini C arm images are obtained to demonstrate anatomic reduction of the AC joint.

Distal Clavicle Excision Versus Acromioclavicular Joint Repair

For acute AC joint separations, our preferred approach is to perform an AC joint repair (Figure 12).

  • Simple or figure-of-eight sutures using a no. 0 non-absorbable suture are used to repair the AC joint capsule and ligaments primarily. The posterior and superior ligaments are critical in preventing posterior and superior displacement of the clavicle.

  • The long limb of the graft exiting the lateral (trapezoid) tunnel is taken laterally and looped on top of the AC joint and used for augmentation of the AC joint capsule repair.

  • The short limb of the graft exiting the medial tunnel is folded laterally and sewn to the base of the graft exiting the trapezoid tunnel.

In chronic dislocations, two options exist:

  • One approach is to repair the AC joint as described above.

  • An alternative approach is to perform a distal clavicle excision especially if AC joint arthrosis is a concern. An oscillating saw is used to remove enough bone from the distal end of the clavicle (<1 cm) to prevent any mechanical contact with the acromion.

Pearls and Pitfalls of Technique

Anatomic Coracoclavicular Ligament Reconstruction

  • The patient’s head should be slightly tilted away from the surgical field and not taped tightly to the bed so as to allow room for drilling of a tunnel for conoid ligament attachment.

  • Graft ends should be bulleted for easy passage through tunnels.

  • The AC joint should be slightly overreduced prior to fixation of the graft in clavicle tunnels.

  • Smaller bone tunnels should be used in the clavicle to prevent intra-operative or post-operative fractures of the clavicle.

  • Deltotrapezial fascia should be meticulously closed at the end.

Potential Complications

Procedure Specific Complications
  • ACCR: coracoid fracture, clavicle fracture, clavicular or coracoid osteolysis, hypertrophic distal clavicle, osteoarthritis of AC joint

  • Modified Weaver-Dunn: clavicle fracture, hardware complications

Complications Common to all Procedures
  • Loss of reduction and recurrence of deformity

  • Foreign body reaction to synthetic material

  • Adhesive capsulitis

  • Infection

  • Brachial plexopathy

  • Hardware complications (broken hardware, symptomatic hardware, migrating hardware)

Post–operative Rehabilitation

The goals of post-operative rehabilitation are to restore and reinforce the stability to the AC joint through strength training of the supporting muscles of the shoulder girdle and to achieve pain free movement of shoulder.

  • Post-operative support with a platform brace is a must for 6 to 8 weeks. The platform brace supports the arm and minimizes the gravity-induced stress on the AC joint reconstruction and is an essential facet of early post-operative management. For the first 6-8 weeks, the brace may be removed for grooming and supine gentle passive range of motion only.

  • Early intervention is directed toward reducing pain and inflammation to allow strength-based exercise to begin as soon as possible.

  • Patients are formally referred to rehabilitation following 8 weeks of immobilization. From 8 weeks to the 12-week mark, rehabilitation is focused on restoring shoulder range of motion and scapular control.

  • From 12-18 weeks, the focus of rehabilitation shifts from mobility to strength and control. Strength exercises for the scapular muscles include low rowing (involving no motion of the upper extremity), horizontal abduction with external rotation, and prone horizontal extension with the arm at 100 degrees of shoulder abduction (“Ts” and “Ys”).

Outcomes/Evidence in the Literature

There are no level 1 studies comparing ACCR to non-operative treatment or other common alternative treatment options (Weaver-Dunn procedure) for AC joint separations. The long-term outcome data (5 years or more) for the ACCR is not available in literature. The short-term data (<2-3 years data) demonstrates that the majority of patients report a significant relief of pain, return of normal strength and function, and negligible loss of motion. Some loss of radiographic reduction (<5 mm change in CC distance) is common but not clinically significant. Subjective and standardized outcome measures showed high satisfaction rates. Outcomes with the Weaver-Dunn procedure are difficult to compare due to the variations in the Weaver-Dunn method used and the makeup of the type of patients and severity of injury within study groups.

Rauschning, W, Nordesjo, LO, Nordgren, B. “Resection arthroplasty for repair of complete acromioclavicular separations”. Arch Orthop Trauma Surg. vol. 97. 1980. pp. 161-164. (Rauschning et al. reported 12 acute and 5 chronic type III AC joint injuries treated by the Weaver-Dunn procedure (isolated CA ligament transfer). At follow-up 1-5 years after the operation, all patients had stable and painless shoulders with resumption of full activities and functionally excellent results even though there was 21% loss of reduction (level IV evidence) PUBMED:7447665.)

Tienen, TG, Oyen, J, Eggen, PJ. “A modified technique of reconstruction for complete acromioclavicular dislocation: a prospective study”. Am J Sports Med. vol. 31. 2003. pp. 655-659. (Tienen et al. presented 21 patients with Rockwood type V AC joint dislocations who underwent a modified Weaver-Dunn procedure with clavicle reduction and AC joint fixation using absorbable braided sutures. At a mean follow-up of 35.7 months, 18 patients had returned to their sports without pain within 2.5 months after operation; the average Constant score at last follow-up was 97. Radiographs taken at this time showed residual subluxation in two patients and, in one patient, redislocation of the joint that occurred because of infection (level IV evidence) PUBMED:12975182.)

Martetschlger, F, Horan, MP, Warth, RJ, Millett, PJ. “Complications After Anatomic Fixation and Reconstruction of the Coracoclavicular Ligaments”. Am J Sports Med. 2013. (Martetschlager et al. reported outcomes on anatomic CC reconstruction (tendon graft or cortical fixation button) in 59 shoulders with a mean age of ~43 years. At a mean follow up of 2.4 years, the 12- and 24-month construct survivorship was calculated to be 86.2% and 83.2%, respectively. There was a significant improvement in the American Shoulder and Elbow Surgeons (ASES) scores and SF-12 physical component scores post-operatively. The complication rate was ~28% (13/46) and included 4 graft ruptures, 2 clavicle fractures, 1 case of hardware failure, 1 hypertrophic distal clavicle, 2 cases of hardware pain, 1 suture granuloma, 1 case of adhesive capsulitis, and 1 case of axillary neuropathy PUBMED:24007761.)

Nicholas, JS, Lee, SJ, Mullaney, MJ, Tyler, TF, McHugh, MP. “Clinical outcomes of coracoclavicular ligament reconstructions using tendon grafts”. AJSM. vol. 35. 2007. pp. 1912-1917. (Nicholas et al. reported a high satisfaction rate (89%), low complication rate, and significantly improved outcome scores and no loss of reduction at a minimum follow up of 1 year (mean 24 months) PUBMED:17687120.)

Carofino, BC, Mazzocca, AD. “The anatomic coracoclavicular ligament reconstruction: surgical technique and indications”. J Shoulder Elbow Surg. vol. 19. 2010. pp. 37-46. (Carafino et al., in a series of 17 patients, reported a significant improvement in the outcome scores (ASES and Constant Murley) at an average of 21 months follow up after ACCR for a type III/V AC joint separation. There were 3 complications ( ~18%) in their series, which included one radiographic loss of reduction, one infection and one patient with chronic AC joint pain PUBMED:20188267.)

Weinstein, DM, McCann, PD, McIlveen, SJ. “Surgical treatment of complete acromioclavicular dislocations”. Am J Sports Med. vol. 23. 1995. pp. 324-331. (When chronic and acute repairs of type III AC joint injuries were studied, patients with early repair were significantly better after 3 months. In a study by Berg EE, Ciullo JV. The SLAP lesion: a cause of failure after distal clavicle resection. Arthroscopy 1997;13:85-89 PUBMED:7661261).


Acromioclavicular joint injuries involve varying degrees of injury to the AC and CC ligaments and is a common sports-related shoulder injury. Acromioclavicular joint separations are graded according to the severity of injury to AC and CC ligaments and radiographic displacement of AC articulation. There is significant debate regarding operative versus non-operative management of type III AC joint injuries. The ideal surgical technique for complete AC joint separation is not known. There are no level 1 studies comparing different surgical techniques and their outcomes and complications. Lower grade separations (types I-III) are initially managed non-operatively and the majority of the patients do well. Operative treatment is indicated for higher-grade separations (types IV-V) and for type III injury that occurs in a high demand athlete or has failed conservative management. Post-operative immobilization and rehabilitation is an essential component of the AC joint reconstructive process.