Overview
Acromioclavicular (AC) joint separations are common shoulder injuries.
Low-grade injuries (Rockwood types I and II) are usually treated successfully without surgery.
High-grade injuries (types IV, V and VI) are generally considered operative lesions.
Type III remains controversial. Most are treated nonoperatively, but treatment must be tailored to the patient. (Campbell)
Associated glenohumeral lesions occur in up to 53% of high-grade separations. These are mostly articular-sided rotator cuff tears and SLAP tears, and advancing age is the strongest predictor. This is one argument for arthroscopically assisted stabilization, which also lets the surgeon see suture-passing devices directly beneath the coracoid, where neurovascular structures lie close. (Campbell)
Evaluation and Classification
Mechanism. Usually a direct blow to the lateral shoulder or acromion with the arm adducted. The injury progresses from the AC ligaments to the coracoclavicular (CC) ligaments and then the deltotrapezial fascia. (Rockwood)
Examination. Look for point tenderness and prominence at the AC joint, a positive cross-body adduction test, and AC-localized pain on the O'Brien active compression test. (Rockwood)
Imaging. Plain radiographs remain the most accessible and cost-effective routine study. (Rockwood)
Zanca view: beam tilted 10–15 degrees cephalad, at about 50% of standard AP penetration, compared with the contralateral side.
Axillary view: shows anteroposterior position of the clavicle and identifies type IV injuries.
Stryker notch view: shows the coracoid base and coracoid fractures.
Radiographic features of high-grade types (Rockwood)
Type IV: the distal clavicle is displaced posteriorly behind the acromion. It is best seen on the axillary view, and bilateral CT can help when an axillary view cannot be obtained.
Type V: the CC distance is markedly increased (100%–300%). The clavicle is often buttonholed through the deltotrapezial fascia and cannot be reduced.
Type VI: inferior dislocation, either subacromial or subcoracoid. It is very rare and the result of severe trauma, so look for associated rib, clavicle and intrathoracic injuries.
Coracoid fracture variant. A complete AC separation with a coracoid process fracture, with the CC ligaments intact and attached to the coracoid fragment. Most authors favor nonoperative care. Open reduction and internal fixation may be needed if the fragment carries a significant part of the glenoid fossa and is displaced. (Rockwood)
Indications and Treatment Selection
Nonoperative care (Rockwood authors' approach)
Used for all type I and II and most type III injuries, with close observation.
Start with a sling that supports and elevates the arm to unload the injured ligaments.
Low-grade injuries: range of motion can begin within 1 week and is typically pain-free by 2–3 weeks.
Higher-grade injuries: formal physical therapy for periscapular strengthening starts at 2 weeks.
Defer heavy lifting and contact sports until motion is full and the joint is no longer tender, usually 2–4 weeks. Contact sport typically resumes at 4–6 weeks.
Unless neurologic or skin problems demand earlier intervention, patients get a 6-week trial of nonoperative care before surgery is considered. (Rockwood)
Evidence for nonoperative care. Randomized trials of complete (type III–V) injuries found that nonoperative treatment gave better early outcome scores and an earlier return to work. Comparisons were with hook plate fixation (Canadian Orthopaedic Trauma Society) and with suspensory TightRope fixation. At 1 year, functional results did not differ. A small but persistent group of nonoperatively treated patients remain unhappy and later need reconstruction. (Rockwood)
Operative treatment (Rockwood)
Selected type III and most type IV and V injuries in young, active patients.
Type IV–VI injuries in polytrauma patients, in whom AC joint injuries have been linked to worse shoulder outcomes.
Graft augmentation. Injuries older than 2 weeks receive supplemental anterior tibialis allograft augmentation, to reduce the risk of loss of reduction and implant-related complications. The number and diameter of drill holes in the clavicle and coracoid are kept to a minimum to reduce fracture risk. (Campbell)
Technique 57.27: Arthroscopically Assisted AC Joint Reconstruction (Campbell)
Arthroscopic preparation
Place the patient in the beach-chair position.
Examine AC joint stability and how easily the joint reduces. Confirm that the shoulder can be imaged fluoroscopically.
Create a standard posterior portal. Perform diagnostic arthroscopy with a 30-degree scope and treat associated pathology.
Create a standard anterior portal high and slightly lateral in the rotator interval.
Take down the rotator interval with a shaver and electrocautery, preserving the superior and middle glenohumeral ligaments. This exposes the coracoacromial ligament and the coracoid.
Create a low accessory anterolateral portal in line with the upper border of the subscapularis. Insert a clear 8.25-mm cannula and switch to a 70-degree scope for the rest of the case.
Clear the undersurface of the coracoid of soft tissue and lightly decorticate it. Reach the medial extent of the coracoid, where the pectoralis minor inserts.
Clavicular exposure
Confirm with fluoroscopy that the superior incision lies over the clavicle, about 3 cm medial to the AC joint.
Make a 3- to 4-cm vertical incision over the clavicle. An alternative is a longitudinal incision over the anterior third of the clavicle.
Raise full-thickness flaps and incise the clavipectoral fascia in line with the clavicle.
Free the clavicle anteriorly and posteriorly so the graft can be passed, and mobilize it until the AC joint reduces easily.
If necessary, resect the distal 5–8 mm of the clavicle with a microsagittal saw.
Suspensory fixation
With the arm supported in a positioner, reduce the AC joint.
Introduce the AC joint drill guide through the anterior portal and seat it at the base of the coracoid, centered from medial to lateral. Under fluoroscopy, place its other end on the clavicle in line with the coracoid.
Advance the 2.4-mm guide pin through four cortices until it exits the inferior coracoid at the intended point. Confirm with fluoroscopy and remove the guide.
Overdrill the superior clavicular cortex so the knotless "top hat" sits flush.
Pass a nitinol wire through the drill sleeve and retrieve it out of the low anterolateral cannula. Use it to shuttle the TightRope suture limbs through the clavicle and coracoid.
Load a cortical button onto the suture limbs and seat it at the base of the coracoid with a grasper.
Tension the limbs and seat the "top hat" on the superior clavicle to reduce the AC joint completely. Confirm with fluoroscopy. Leave the limbs for later tying.
Graft passage (allograft augmentation)
Create the medial passage first. Place a switching stick just medial to the TightRope, starting at the posterior clavicle and exiting along the medial coracoid. Advance a cannula dilator over the stick, replace the stick with a suture shuttle and retrieve it out of the anterolateral cannula.
Repeat on the lateral side, starting just lateral to the TightRope and anterior to the clavicle, and passing lateral to the coracoid.
Whipstitch both ends of an anterior tibialis tendon allograft.
Shuttle the graft posterior to the clavicle and medial to the coracoid, then around the coracoid so it exits anterior to the clavicle. The graft should lie over the cortical button on the coracoid undersurface.
Finish tensioning the TightRope and tie its sutures.
Tie the graft over the clavicle and secure it to itself with two figure-eight No. 2 nonabsorbable sutures. Excise the excess. Alternative: fix one graft limb to the medial acromion with a 1.8-mm double-loaded all-suture anchor to reconstruct the superior AC ligaments and capsule.
Obtain final fluoroscopic images.
Close the clavipectoral fascia with No. 0 absorbable suture, then close the wounds.
Technical points from Rockwood (open/anatomic reconstruction)
Expose the AC joint adequately and remove scar or calcified tissue from the CC space, including the meniscus homologue if needed. Failing to do so is one of the most common operative errors and prevents anatomic reduction.
Keep clavicular bone tunnels smaller than 5.5 mm. Leave an adequate bone bridge between the tunnels and between each hole and the cortices to avoid fracture.
Repair the deltotrapezial fascia meticulously ("vest-over-pants"). It adds strength and blood supply to the reconstruction.
Rockwood's practice is to preserve the AC articulation where possible. If any distal clavicle is removed, take it from the posterior edge, where abutment against the posterior acromion typically causes pain.
Hook plate pitfalls: trial several hook depths before choosing a size (measuring distal clavicle thickness on preoperative radiographs guides the depth); contour the hook to the undersurface of the acromion to avoid point loading, overreduction and acromial erosion; obtain adequate medial screw fixation; plan removal at 9–12 months to limit acromial osteolysis and implant-related pain. After removal, avoid athletic or contact activity for 6–8 weeks. (Rockwood)
Postoperative Care
After Campbell Technique 57.27
Sling immobilization for 6 weeks, to limit gravity forces on the construct.
Hand, wrist, elbow and pendulum exercises from the first day.
Gentle passive shoulder motion with physical therapy from 4 weeks.
Unrestricted active motion from 6 weeks.
Strengthening from 10–12 weeks. (Campbell)
After anatomic reconstruction (Rockwood)
Strengthening of the scapular stabilizers from 6–12 weeks, once motion is pain-free.
Weight training from 3 months.
Full contact athletics from 6 months.
Regaining peak strength, especially for pressing and lifting from the floor, generally takes 9 months to a year. (Rockwood)
Complications
Overall rates. A recent meta-analysis cited by Campbell reports failure in 21.8% and complications in 14.2%. Anatomic CC reconstruction has complication rates of 13%–27%. (Campbell; Rockwood)
Loss of reduction. Reported in 10%–30%, with the range driven partly by inconsistent radiographic criteria. Suspensory devices and hook plates can still fail, because the weight of the whole upper extremity rests on the fixation. Early reports of cortical-button techniques showed high rates of loss of reduction (33%), complications (27%–44%) and reoperation (24%). Newer series compare favorably with biologic graft reconstruction. (Rockwood)
Fracture. Clavicle fracture through bone tunnels, and coracoid base fracture, can be a failure mode of suspensory fixation. (Rockwood)
Graft problems. Graft resorption or rupture, graft erosion, foreign-body reaction and infection. Late infections linked to nonabsorbable tape or suture have been reported. (Rockwood)
Implant problems. Implant failure, prominence or irritation. Hook plates cause acromial osteolysis and erosion and usually need removal. (Rockwood)
AC arthritis. Symptomatic AC arthritis can be treated by excising the distal 8–10 mm of the clavicle. (Rockwood)
General complications. Wound infection and osteomyelitis. Monitor wounds closely in the first few weeks. (Rockwood)
References
Brolin TJ, Lamplot JD. Arthroscopy of the upper extremity. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 57, Technique 57.27.
Hebert-Davies J, Sniderman J, Nauth A. Acromioclavicular and sternoclavicular joint injuries. In: Tornetta P III, Ricci WM, Ostrum RF, McKee MD, Ollivere BJ, de Ridder VA, eds. Rockwood and Green's Fractures in Adults. 10th ed. Wolters Kluwer; 2024. Chapter 32 (Turkish edition: Erişkin Kırıkları).