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    A Case of Type V Acromioclavicular Joint Separation in a Young Laborer

    A left-hand dominant male laborer presents with left shoulder pain and deformity after a fall snowboarding. Radiographs demonstrate an acromioclavicular joint separation with more than 2 cm of superior displacement of the clavicle above the acromion. What is the next step in the management of this patient’s injuries?

    Author

    Ashley J. Bassett, MD

    Introduction

    Injury to the acromioclavicular (AC) joint is very common and accounts for 9% of shoulder girdle injuries. Nearly half of all AC joint injuries occur in young adults under age 30. [1,2] The rate of AC joint injury is higher in males as well as in athletes involved in contact sports such as football, rugby, hockey, and wrestling and high-velocity sports such as skiing and cycling. [3]

    Traumatic injury to the AC joint typically results from a direct impact to the superior or superolateral aspect of the shoulder with the arm in an adducted position. [2] The acromion and scapula translate inferomedially while the centrally stabilized clavicle maintains its relative position, resulting in various disruption of the AC joint complex depending on the magnitude and direction of the force.

    RELATED: Save the date for ICJR’s 10th Annual Shoulder Course, October 7-9, 2021, in Las Vegas

    The AC joint is a diarthrodial articulation that contributes greatly to proper function of the shoulder girdle and is supported by both dynamic and static stabilizers. [4] Dynamic stabilization is provided by the attachments of the trapezius and anterior deltoid muscles. Static stability of the AC joint complex has several contributions:

    • The joint capsule is reinforced by the AC ligaments and provides horizontal stability. The posterior and superior capsuloligamentous structures are particularly important for resisting excessive posterior translation of the distal clavicle. [5,6]
    • Vertical stability of the AC joint is provided by the 2 coracoclavicular (CC) ligaments that span from the inferior clavicle to the coracoid process. [5]
    • The conoid ligament is located more medial and is the primary restraint to superior translation of the distal clavicle, with the more lateral trapezoid ligament taking on a lesser role. [5]

    The Rockwood radiographic classification system separates AC joint injuries into 6 injury patterns based on type and amount of clavicle displacement, and it is useful to guide treatment. [1] Types I and II are low-grade injuries with partial tears of the AC and CC ligaments:

    • A type I injury is an isolated partial tear of the AC ligaments with normal radiographs.
    • A type II injury is a complete tear of the AC ligaments and partial tear of the CC ligaments, with mild radiographic asymmetry but less than 25% superior displacement of the distal clavicle compared with the uninjured shoulder.

    Types III-VI are high-grade injuries with complete disruption of the AC and CC ligaments, differing in the amount and direction of clavicle displacement.

    • A type III injury is characterized by 25% to 100% superior displacement of the distal clavicle compared with the uninjured shoulder.
    • A type IV injury consists of posterior dislocation of the distal clavicle into the trapezius muscle.
    • A type V injury is a more severe type III injury, with greater than 100% superior displacement of the distal clavicle compared to the uninjured shoulder.
    • A type VI injury involves inferior dislocation of the distal clavicle, either subacromial or subcoracoid.

    In general, type I and II injuries are treated non-operatively, with a brief period of sling immobilization followed by physical therapy that emphasizes scapular control and shoulder girdle strengthening. [7] Treatment of type III injuries remains controversial and depends on a multitude of factors, including the patient’s age, activity level, hand dominance, type of sport, and position. Typically, treatment will start with non-operative management and close monitoring of the patient’s pain, AC joint stability, and scapular function. [8] Type IV, V and VI injuries are often managed surgically with AC joint reduction and ligament repair or reconstruction.

    This article presents a case of a type V AC separation that was treated with open AC joint reduction and CC ligament reconstruction.

    Case Presentation

    A 20-year-old, left-hand dominant male presents with left shoulder pain and deformity after a fall when snowboarding 1 week earlier. The patient reports that he was doing a flip and landed onto the superolateral aspect of the left shoulder. He experienced a pop with immediate onset of pain and deformity localized to the left acromioclavicular joint.

    The patient notes a painful “shifting” and “grinding” sensation along the superior aspect of the left shoulder. He denies a prior history of left shoulder pain or injury. He had no previous injections or surgery on the left shoulder girdle.

    The patient is a steelworker and participates in recreational sports including basketball and snowboarding. His goal is to be able to return to his overhead laboring job without functional limitation.

    Physical Exam

    • Height: 70 inches; weight: 200 pounds
    • Clean, dry, intact skin with no surgical scars
    • Obvious deformity of the left AC joint with superior prominence of the distal clavicle; does not reduce with shoulder shrug
    • Left AC joint tender to palpation
    • Significant horizontal instability with manual anterior-to-posterior shucking of the distal clavicle
    • No deformity of the left sternoclavicular (SC) joint or clavicle shaft
    • No tenderness to palpation or instability of the left SC joint
    • Full passive range of motion (ROM) of the shoulder in all planes
    • Active ROM and shoulder manual muscle strength testing limited by pain
    • Positive crossbody adduction and active compression tests, with pain localized to the left AC joint with both tests
    • Neurovascularly intact distally

    Imaging

    Imaging evaluation for suspected AC joint injury begins with plain radiographs of the shoulder – anteroposterior (AP), scapular Y, and axillary views – and the bilateral AC joints with the Zanca view, an AP view with a 10° to 15° cephalic tilt, for comparison of the coracoclavicular distance (Figures 1-3). The addition of weighted views is helpful to differentiate between a type II and type III injury, if patients can tolerate it based on pain.

    Figure 1. Anteroposterior radiograph of the bilateral AC joints obtained with a 15°cephalic tilt (Zanca view) shows a left AC joint separation injury with greater than 100% superior translation of the distal clavicle. The CC distance measures 31.3 mm on the left compared with 11.7 mm on the contralateral uninjured side, consistent with vertical instability. The distal clavicle is displaced 2.6 cm above the level of the acromion.

    Figure 2. Axillary radiograph of the left shoulder shows posterior translation of the distal clavicle (green outline) relative to the acromion (blue outline), indicative of horizontal instability.

    Figure 3. Scapular Y radiograph of the left shoulder shows the distal clavicle overriding the acromion, which is consistent with horizonal instability.

    Obtaining an MRI of the involved shoulder can be useful to identify associated injuries of the shoulder girdle, such as labrum and rotator cuff tears, but is not routinely necessary for diagnosis. An MRI was not obtained in this patient, as his history and examination were consistent with an isolated AC joint injury and an open reconstruction was planned.

    Diagnosis

    • Left shoulder type V AC joint separation, with complete disruption of the AC joint capsule, AC ligaments, and coracoclavicular ligaments and gross vertical and horizonal instability

    Treatment

    I had a long discussion with the patient regarding his diagnosis, treatment thus far, and next best steps in management. Conservative treatment options were discussed, including a brief period of sling immobilization for soft tissue rest; formal physical therapy that would emphasize scapular control to lessen the development of scapular dyskinesis; and pain control with oral anti-inflammatory medications, cryotherapy, and intra-articular lidocaine injection.

    We then discussed the risks and benefits of surgical intervention in the form of left shoulder open AC joint reconstruction with anatomic reconstruction of the CC ligaments and AC ligaments using non-irradiated soft tissue allograft. Risks of this approach include but are not limited to:

    • Infection
    • Bleeding
    • Pain at the AC joint
    • Pain relating to symptomatic hardware
    • Loss of reduction with recurrent deformity of the AC joint
    • Implant complication and/or breakage
    • Clavicle fracture relating to bone tunnel placement
    • Disease transmission with use of allograft tissue
    • Need for additional surgery, such as removal of hardware or revision reconstruction

    The patient verbalized understanding of the risks and benefits, agreed to comply with the postoperative rehabilitation protocol, and elected to proceed with surgery.

    Procedure

    Positioning, Prep, and Drape

    • An interscalene nerve block was administered for perioperative pain control and general anesthesia was induced.
    • The patient was placed in the beach chair position with appropriate padding of all bony prominences.
    • Examination under anesthesia was performed and was notable for full glenohumeral joint motion symmetric to the contralateral shoulder with no instability. A deformity of the left AC joint with superior displacement of the distal clavicle was not reducible.
    • The left chest, shoulder, and upper extremity were prepped and draped in the usual sterile fashion.

    Preparation of the Tibialis Anterior Allograft

    • A non-irradiated tibialis anterior allograft measuring 8 mm in diameter by 290 mm in length was removed from sterile packaging and thawed in room temperature sterile saline.
    • The graft was trimmed and whip-stitched on both ends using 2-0 FiberWire (Arthrex; Naples, Florida).
    • The graft fit easily through a 5.5 mm sizing block and snuggly through a 5.0 mm sizing block.
    • Fifteen pounds of tension were applied for 15 minutes to precondition the graft.
    • The graft was then wrapped in a moist vancomycin-soaked sponge (5 mg/mL concentration) until implantation.

    Surgical Approach and Provisional Reduction of the AC Joint

    • An oblique longitudinal saber incision was made from the posterior edge of the AC joint traversing distally to the superior edge of the coracoid using a 15-blade scalpel.
    • Soft tissue planes were bluntly developed medially and laterally. Electrocautery was used to maintain hemostasis.
    • The deltotrapezial fascia was identified and incised in line with the clavicle. The fascia was elevated off the clavicle, creating full-thickness flaps anteriorly and posteriorly to the lateral portion of the clavicle and medial acromion, preserved for later repair.
    • The AC joint and surrounding soft tissue were thoroughly debrided, essentially skeletonizing the distal clavicle and medial acromion, to ensure an absence of tissue interposition that would prevent proper joint reduction.
    • A trial reduction was performed and the distal clavicle was noted to reduce weell to the acromion on intraoperative fluoroscopy Zanca view (Figure 4). Resection of the distal clavicle was not performed, reducing the risk of postoperative instability of the AC joint.

    Figure 4. Intraoperative fluoroscopy Zanca view of the left AC joint shows a left type V AC joint separation injury with superior displacement of the distal clavicle before reduction (A) and after provisional reduction of the AC joint (B).

    Creation of 2 Clavicular Bone Tunnels

    • Once the lateral aspect of the clavicle was sufficiently exposed and mobilized, we began placement of the clavicular bone tunnels that we would use to anatomically restore the CC ligaments.
    • A 5-mm cannulated reamer was utilized to create 2 bone tunnels corresponding with the anatomic locations of the conoid and trapezoid ligaments.
    • A 2.4-mm guide pin was placed for the conoid tunnel, positioned 4.5 cm medial to the AC joint and within posterior half of the clavicle, roughly even with the medial edge of the coracoid process (Figure 5). The 5-mm cannulated reamer was placed over the guide pin and the posterior aspect of the clavicle was inspected to ensure that the reamer would not blow out the posterior cortex.
    • After appropriate position of the conoid tunnel was confirmed, a second 2.4-mm guide pin was placed for the trapezoid tunnel, positioned within the center point of the clavicle anterior-to-posterior and approximately 20 mm lateral to the center of the conoid tunnel (Figure 5).

    Figure 5. Intraoperative fluoroscopy Zanca view of the left AC joint shows placement of the first guide pin in the anatomic footprint of the conoid ligament medially and the second guide pin in the anatomic footprint of the trapezoid ligament laterally.

    • A cannulated reamer was then placed over the guide pin and the planned tunnel position was checked to ensure that the tunnel was distanced 20 mm to 25 mm medially from the end of the clavicle and that at least 10 mm of bone remained between the tunnel edge and the anterior cortex.
    • A cannulated reamer was placed on each guide pin and the distance between the 2 reamers was measured to ensure that a solid bone bridge of 15 mm existed between the 2 tunnels to minimize susceptibility to clavicle fracture (Figure 6).

    Figure 6. Intraoperative photograph shows placement of the 5.0mm cannulated reamer on each guide pin to ensure adequate spacing between the 2 tunnels and to confirm appropriate tunnel positioning relative to the distal end of the clavicle as well as the anterior and posterior edges of the clavicle.

    • Once the tunnel positions were confirmed, the 5-mm reamer was used to create the 2 bone tunnels through the entire width of the clavicle.
    • The tunnels were tapped with a 5.5-mm tap to ease later screw placement and decrease fracture risk.
    • The surgical wound was copiously irrigated to remove bony debris.

    Placement of Shuttle Sutures (Figure 7)

    • A Hewson suture passer was used to place a #1 Vicryl shuttle suture (Ethicon; Somerville, New Jersey) through each clavicular tunnel for later graft passage.
    • The suture passer was used to place a shuttle suture around the clavicle inferiorly from anterior to posterior for later passage of the FiberTape Cerclage (Arthrex; Naples, Florida) circumferentially around the clavicle.
    • Under direct visualization, a coracoid graft passing instrument was looped under the coracoid from medial to lateral to protect the neurovascular structures. A FiberStick suture (Arthrex; Naples, Florida) was passed and a loop was fashioned medially.

    Figure 7. Intraoperative photograph shows interval placement of the 2 clavicular bone tunnels, followed by passage of 4 shuttle sutures through the conoid tunnel medially, trapezoid tunnel laterally, circumferentially around the clavicle, and inferior to the coracoid.

    Passage of the Graft and FiberTape Cerclage

    • With all shuttle sutures in place, we moved forward with passage of the tibialis anterior allograft and FiberTape cerclage.
    • The graft and FiberTape cerclage were first passed beneath the coracoid process from medial to lateral.
    • The FiberTape cerclage was then shuttled inferior to the clavicle from anterior to posterior.
    • The 2 limbs of the graft, accompanied by a free FiberTape suture, were then crossed and shuttled through the clavicular tunnels. The graft limb exiting the trapezoid tunnel was made longer to later recreate the AC ligaments and joint capsule (Figure 8).

    Figure 8. Intraoperative photograph shows passage of the graft and the FiberTape cerclage inferior to the coracoid. The FiberTape cerclage was passed inferior to the clavicle. The graft was crossed and passed through the clavicular bone tunnels to reconstruct the conoid and trapezoid ligaments.

    Reduction of the AC Joint and Cerclage Fixation

    • The FiberTape cerclage was passed over the top of the clavicle from posterior to anterior, draped between the 2 bone tunnels, to reach the other end of the cerclage anteromedially. The cerclage suture was then loaded to the pre-tied knot to complete the FiberTape cerclage loop. Gross slack was removed from the construct.
    • Once the graft and FiberTape cerclage were positioned appropriately, we reduced the AC joint with upward displacement of the scapulohumeral complex and downward force applied to the distal clavicle. Intraoperative Zanca view fluoroscopy was utilized to confirm slight over-reduction of the AC joint to account for inevitable creep in the reconstruction.
    • With reduction maintained, the FiberTape cerclage was gradually tightened using the tensioner, further securing the reduction while ensuring that the cerclage knot remained infraclavicular to avoid knot prominence. The cerclage suture limbs were then tied together with 2 alternating half-hitches. The cerclage construct was tensioned again and the suture tails were cut.

    Graft Fixation to Complete CC Ligament Reconstruction

    • To remove any remaining slack, the graft was cyclically loaded by pulling it up on both ends.
    • With maximum tension applied to the graft, a 5.5 mm x 8 mm PEEK tenodesis screw (Arthrex; Naples, Florida) was inserted into the conoid bone tunnel to secure the graft medially. Fluoroscopy was again used to confirm maintained reduction.
    • With maximum tension maintain on the lateral limb of the graft, a second 5.5 mm x 8 mm PEEK tenodesis screw was inserted into the trapezoid tunnel to secure the graft laterally.

    AC Ligament Reconstruction

    • The excess graft was used to reconstruct the AC ligaments and joint capsule.
    • The lateral graft limb from the trapezoid tunnel was brought across the superior aspect of the AC joint and sutured to the posterior tissue on the acromial side of the joint.
    • The remaining graft was shuttled around the AC joint from posterior to anterior and then sutured to itself, as well as to the anterior tissue on the acromial side of the joint (Figure 9).

    Figure 9. Illustration (A) and corresponding intraoperative photograph (B) show the final reconstruction construct.

    Completion of the Procedure

    • Successful reduction was confirmed on fluoroscopic Zanca view (Figure 10).

    Figure 10. Intraoperative fluoroscopy Zanca view of the left AC joint shows the final AC joint reconstruction with successful reduction of the joint and 2 bone tunnels anatomically positioned in the clavicle.

    • The surgical wound was copiously irrigated and the deltotrapezial fascia was then closed in an interrupted fashion with #1 Vicryl suture. The subcutaneous tissue was closed with a combination of 2-0 Vicryl suture deeper and 3-0 Monocryl suture (both from Ethicon; Somerville, New Jersey) more superficial in an interrupted fashion.
    • The skin was closed with running 3-0 Quill Monoderm suture (Surgical Specialties Corporation; Westwood, Massachusetts) subcuticularly, followed by the Dermabond Prineo skin closure system (Ethicon; Somerville, New Jersey) with application of a mesh and skin glue. The surgical incision was covered with a waterproof silver impregnated dressing.
    • The shoulder was then placed in a pillow abduction sling. A cryotherapy cold pad was placed over the shoulder, avoiding direct contact with the skin.

    Postoperative Protocol

    The typical postoperative rehabilitation protocol for AC joint reduction and reconstruction is structured to protect the surgical reconstruction, with early protected passive ROM in the early phase and progressive ROM and strengthening in the later phases. A pillow abduction sling is applied immediately postoperatively and is worn by the patient for 6 weeks. Hand, elbow, and wrist motion are encouraged immediately postoperatively.

    Below is the postoperative protocol utilized by the author to facilitate safe rehabilitation in this patient. It is important to note that progression through the protocol may vary from patient to patient. If there is any concern about the robustness of the reconstruction, physical therapy (PT) and all shoulder ROM should be delayed 4 weeks to protect the healing tissue.

    Days 07

    • Immobilize the operated shoulder in the sling at all times, except for hygiene. Ensure that the sling is appropriately tightened to support the weight of the arm.
    • Avoid shoulder ROM.
    • Change the dressing, obtain radiographs to confirm reduction (Figure 11), and provide a PT prescription at the first postoperative visit 7 days after surgery.

    Figure 11. Anteroposterior Zanca view of the left AC joint shows AC joint reconstruction with 2 clavicular tunnels and maintained reduction of the AC joint.

    Weeks 14

    • Immobilize the operated shoulder in the sling at all times, except for hygiene and PT exercises.
    • Begin passive shoulder ROM under PT guidance, limited to forward flexion 90, abduction 45, external rotation 60.
    • Begin deltoid and rotator cuff isometric exercises in neutral in all planes (flexion and extension, internal and external rotation, abduction and adduction).
    • Begin active elbow, wrist, digit, and cervical spine ROM and postural exercises.

    Weeks 48

    • Advance shoulder ROM to active-assisted ROM at 4 weeks and then active ROM at 6 weeks.
    • Progress shoulder ROM to full, with the following restrictions: no crossbody adduction for 8 weeks, no internal rotation behind the back for 8 weeks, and no end-range forward elevation stretching.
    • Discontinue the sling at 6 weeks.
    • Begin light manual resistance exercises and internal and external rotation at mid-range.

    Weeks 812

    • Advance shoulder ROM to full in all planes, with no restrictions.
    • Begin closed-chain scapular exercises and kinetic chain activities.

    Weeks 1216

    • Initiate isotonic rotator cuff and periscapular strengthening activities once full ROM has been achieved.
    • Return to laboring work without restriction once full shoulder ROM and strength (90% contralateral) have been achieved, typically at 16 weeks.

    Months 46+

    • Start sport-specific strengthening at low intensities.
    • Initiate a thrower’s program at 4 months if shoulder ROM and strength are full and demonstrate good scapular control.
    • Clearance for contact sports typically occurs at 6 months.

    Surgical Pearls

    • Ensure that the soft tissue is completely cleared from the distal clavicle and medial acromion, including residual joint capsule and early scar tissue, to permit anatomic reduction of the AC joint.
    • Avoid resecting the distal clavicle when possible, as it contributes to AC joint stability independent of the AC ligaments and capsule. [9] If resection is necessary to facilitate reduction after thorough clearance of soft tissue, do not resect more than 5 mm.
    • Select an allograft with a minimum length of approximately 280 mm. This will ensure that after CC ligament reconstruction, adequate tendon length remains to also reconstruct the AC ligaments and capsule.
    • Whipstitch the allograft ends with 2-0 FiberWire suture to avoid excess bulkiness associated with larger diameter suture, thereby easing passage through the bone tunnels.
    • Place the clavicular bone tunnels in the anatomic footprints of the CC ligaments to best restore native biomechanics. [10] The conoid tunnel should be 4.5 cm medial to the AC joint and within the posterior half of the clavicle. The trapezoid tunnel should be 20 mm lateral to the conoid tunnel and centrally in the clavicle from anterior to posterior.
    • Decrease the risk of clavicle fracture by: (1) Keeping bone tunnels less than 6 mm in diameter, (2) pre-tapping the tunnel with a 5.5-mm tap prior to graft passage and screw fixation, and (3) avoiding tunnel placement within the lateral 25 mm of the distal clavicle where the bone is weakest.
    • Use of FiberTape cerclage for CC fixation obviates the risk of coracoid fracture by avoiding coracoid drilling.
    • Insert the coracoid graft passing instrument beneath the coracoid from medial to lateral to lessen the risk of musculocutaneous nerve injury.
    • Position the FiberTape cerclage knot infraclavicular to minimize prominence.
    • Over-reduce the AC joint slightly to account for inevitable creep in the reconstruction.
    • Reconstruct the AC ligaments and capsule with the remaining graft to further stabilize the AC joint and decrease the load on the reconstructed CC ligaments. [11]
    • Close the deltotrapezial fascia to restore the dynamic stabilizers of the AC joint and for layered closure to lessen risk of infection.

    Discussion

    Traditionally, surgical intervention has been recommended to treat Rockwood types IV, V, and VI AC joint injuries; however, recent evidence suggests that not all high-grade AC joint injuries may require surgery. A systematic review by Chang et al [12] concluded that operative treatment of high-grade AC separations led to better cosmesis and improved radiographic reduction but had a slower return to work and a higher rate of implant complications and infection compared with non-operative treatment. There was no difference in functional outcome scores, return to sport, radiographic osteoarthritis, and need for additional surgery between the 2 groups.

    However, a retrospective study by Dunphy et al [13] found that while most patients with type V injuries were able to return to work after non-operative treatment, the majority did not achieve normal functional outcome scores. Other studies have reported that patients with more than 2 cm of displacement of the clavicle above the acromion are more likely to fail non-operative management. Surgical treatment should be considered for these individuals. [14,15]

    More than 150 surgical techniques have been described to treat AC joint separations and yet no single technique has been shown to be superior to another in terms of complication rate, loss of reduction, and rate of revision. [16,17] These techniques include:

    • Open and arthroscopic approaches
    • Primary repair or reconstruction of the AC and CC ligaments with autograft, allograft, or artificial ligaments
    • AC and/or CC stabilization
    • Various types of fixation including hardware, suture, and suspensory devices.

    Ligament reconstruction is the gold standard for chronic injuries and is being used for acute and subacute injuries with increasing frequency compared with repair and stabilization alone. [18] Ligament reconstruction can be divided broadly into 2 types: non-anatomic and anatomic:

    Nonanatomic reconstruction, termed the modified Weaver-Dunn procedure, involves resection of 10 mm to 20 mm of distal clavicle followed by transfer of the coracoacromial ligament from the acromion to the lateral clavicle. [19] Modern techniques have shifted towards anatomic ligament reconstruction, with use of a free tendon graft to recreate the trapezoid and conoid ligaments.

    Anatomic reconstruction of the CC ligaments more closely restores the native biomechanics of the AC joint complex and demonstrates improved stability compared with non-anatomic reconstruction techniques. [10,20] Additional reconstruction of the AC ligaments and capsule has also been shown to provide further stability to the AC joint, decreasing both translation and joint distraction with rotational loads compared with CC ligament reconstruction alone, and reducing the load on the CC ligaments. [11]

    Maximizing stability of the AC joint at the time of surgery is crucial, as loss of reduction remains the most common complication following AC joint reconstruction. The overall complication rate after surgical treatment of AC joint injuries ranges from 9% to 80% in the literature, with an average rate of 27%. Aside from loss of reduction, other complications include pain relating the symptomatic hardware, AC joint pain, fracture of the coracoid or clavicle, and superficial infection. [17]

    Risk factors for loss of reduction include: [22]

    • Non-anatomic reconstruction
    • Single tunnel reconstruction
    • Medialization of the conoid tunnel
    • Use of a hook plate

    Bone tunnel drilling through the coracoid and/or clavicle increases the risk of fracture; however, there are strategies to mitigate this risk: [23]

    • Drilling tunnels less than 6 mm in diameter
    • Tapping prior to screw placement and
    • Placing the trapezoid tunnel at least 25 mm medial to the distal end of clavicle to avoid the weaker lateral bone

    Looping the graft or fixation device around the coracoid rather than using transosseous tunnels avoids coracoid fracture risk. If coracoid tunnels are to be used, drilling with a center-to-center trajectory to avoid penetrating the lateral cortex decreases fracture risk. [24]

    Despite the relatively high complication rate, surgical treatment of high-grade AC joint injuries generally yields good to excellent functional outcomes in the majority of patients, with low overall clinical failure rates and high percentages of return to sport. [18,25,26] Venjakob et al [25] demonstrated significant improvements in VAS and Constant scores after AC joint stabilization surgery, with 96% of patients remaining satisfied or very satisfied with their outcome at 2 years postoperatively. A systematic review by Kay et al [26] reported a high rate of return to sport after surgical treatment of high-grade AC joint injuries, ranging from 94% to 100%. The rate of return to sport was equivalent among the varous injury types (types III-V), acute versus chronic injuries, and across different surgical techniques.

    More high-quality research is needed to determine the optimal reconstruction technique and to clarify which patients and/or injury types would benefit from acute surgical intervention and which may be treated successfully without surgery. For active patients with high-grade AC separation injuries, particularly those with substantial clavicle displacement greater than 2 cm, AC joint reconstruction is an excellent treatment option to restore shoulder function and enable return to athletic activity.

    Author Information

    Ashley J. Bassett, MD, is an orthopedic sports medicine and shoulder surgeon at the Orthopedic Institute of New Jersey in Morristown, New Jersey. She is former fellow in sports medicine surgery at the Rothman Orthopaedic Institute at Thomas Jefferson University, Philadelphia, Pennsylvania.

    Sports Medicine Section Editor, Rothman Institute Grand Rounds

    Brandon J. Erickson, MD

    Disclosures: Dr. Bassett has no disclosures relevant to this article.

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