Shoulder Separations and Other AC Joint Injuries

Shoulder Separations and Other AC Joint Injuries


Controversy and conundra abound regarding acromioclavicular (AC) joint injuries. For the purposes of this chapter, we have placed these conundra into the following categories: evaluation of the AC joint, treatment, associated pathology, complications, and distal clavicle fractures.


Even the assessment of AC joint separations elicits debate. While the traditional Rockwood classification of AC joint separations (Fig. 6-1) maintains its position as the primary AC joint classification system, differentiating between some of these six types is not always clear from either a clinical or radiographic standpoint. Specifically, it seems the greatest difficulty is differentiating between type III, IV, and V separations.

We believe that a critical component of AC joint separations is the degree of anterior/posterior instability of the distal clavicle. AC joint injuries should be evaluated dynamically because the severity of their resulting dysfunction can depend very much on patient motion and activity. The Rockwood classification system is based on static information and unfortunately does not account for dynamic changes of the distal clavicle with shoulder motion or the degree of AP instability (unless the clavicle is posteriorly dislocated through the trapezius). Our experience leads us to believe that patients who have a great deal of AP instability or a relatively unstable distal clavicle in any plane (no matter what classification of AC separation) do more poorly than those patients who are relatively stable.


  • A 39-year-old male weightlifter was injured in a car crash 6 months prior to presentation and diagnosed with a left type III AC joint injury.

  • Because of initial diagnosis, he was treated with several months of physical therapy and NSAIDs (nonsteroidal antiinflammatory drugs) with little improvement.

  • The patient reports difficulty with lifting activities (which are very important in his job) and difficulty lying on his affected side (waking him up at night).

Physical Exam:

  • On initial inspection, the patient does not have an obvious deformity but only slight prominence of the left distal clavicle.

  • The AC joint is tender to palpation; the distal clavicle is ballotable and reducible; and there seems to be a moderate amount of anterior/posterior motion of the distal clavicle.

  • The deformity is more easily identified with specific provocative physical exam maneuvers noted below.

FIGURE 6-1 Schematic of the six types of AC joint separations. A: Type I injury involves a strain of the AC ligaments only. B: Type II injury includes disruption of the AC ligaments, but the CC ligaments are intact. C: In a type III injury, the AC and CC ligaments are disrupted, but the deltoid fascia remains intact and displacement of the clavicle relative to the coracoid is <100% of the diameter of the clavicle. D: In a type IV injury, the AC and CC ligaments are disrupted, and the clavicle is displaced posteriorly into (inset) or through the trapezius muscle. E: In a type V injury, the AC and CC ligaments are disrupted, and the CC displacement is >100% relative to the contralateral distance. F: In a type VI injury, the clavicle is displaced inferior to the coracoid.

FIGURE 6-2 Plain film x-ray at the time of his initial presentation demonstrates an AC joint separation. The clavicle is elevated just above the acromion; thus, the x-ray most resembles a type III AC joint separation.


  • X-ray demonstrates displacement of the AC joint. However, the clavicle is not quite elevated above the plane of the acromion suggesting a likely type III separation. (Fig. 6-2)

  • MRI images demonstrate edema in the AC joint and elevation of the distal clavicle. However, it is difficult to quantify the exact amount of elevation (Fig. 6-3).

FIGURE 6-3 MRI images (A, B) of the left shoulder demonstrate edema within and around the AC joint but do not give conclusive evidence for classification of the injury.

Physical Exam:

  • One provocative test for evaluating if an apparent type III AC separation is actually a type III is to have the patient lean forward in a chair and place his elbows on the knees. In so doing, the patient protracts the scapula, and this maneuver can accentuate the superior elevation of the distal clavicle and also can help determine if the clavicle shifts posteriorly during scapular protraction (Fig. 6-4).

  • Another helpful maneuver is to have the patient put significant pressure on his elbows—pushing down on his knees. If simply leaning forward does not elucidate the deformity, then sometimes the added protraction force produced by pushing on the knees can reveal the pathology (Fig. 6-5).

Pearls, Pitfalls, and Decision-Making:

While this patient has a type III AC joint separation from a radiographic standpoint, clinically it seems more significant. The patient reports more clinical difficulty with his shoulder than one would typically expect from a standard type III separation. This is likely due to the increased AP instability of the distal clavicle. Because of these findings and his continued symptoms, we were more aggressive with treatment and recommended operative intervention for this patient.

FIGURE 6-4 Photos of the patient’s left shoulder. A: The patient is sitting in a chair and resting the shoulder by the side. B: The patient leans forward and puts his elbows on his knees. This causes protraction of the scapula and demonstrates that the distal clavicle subluxes posteriorly.

FIGURE 6-5 When the patient tries to put pressure on the knees with the elbows—this causes increased protraction force of the scapula which then makes the deformity even more obvious.

Another important consideration in the evaluation of AC joint separations is the reducibility of the joint. Irreducibility can indicate that the distal clavicle has button-holed through the trapezius (Fig. 6-6). Alternatively, irreducibility may occur when the AC joint capsule become
invaginated into the AC joint thereby preventing complete reduction of the distal clavicle (Fig. 6-7). Regardless of the reason for irreducibility, we have found that irreducible AC joint separations can also more commonly fail conservative management. Thus, we are more likely to offer surgery in this situation.

FIGURE 6-6 Schematic of a type IV AC joint separation in which the distal clavicle button holes through the trapezius, thus preventing appropriate reduction of the clavicle to the acromion.

FIGURE 6-7 Schematic of the AC joint capsule becoming invaginated inside the AC joint and thus preventing full reduction of the AC joint.


Timing of Treatment and Necessity of Allograft

Another common source of AC joint controversy involves the timing of treatment of AC joint separations. Should all type III dislocations be treated conservatively initially? Should all type V dislocations undergo acute fixation? Answers to these questions are generally not clear-cut in the literature. We believe that one reason nonoperative management has historically been recommended as the initial treatment of choice is because there is a lack of safe and effective operative treatments. For decades, the Weaver-Dunn reconstruction was the surgical answer to this condition; yet, we know that strength of this repair is extremely poor (Fig. 6-8). However, newer techniques not only offer significantly greater strength of repair but can also be performed much less invasively and in most cases—arthroscopically.

FIGURE 6-8 Bar graph of the load to failure of various AC joint fixation methods. (Data from compilation of multiple studies.)

So this begs the question of whether early fixation would offer more reliable clinical and radiographic outcomes for many more patients with acute AC joint separations than are currently being treated operatively. Some of us believe quite strongly that early operative fixation of AC joint separations (specifically, type III) improves clinical and radiographic patient outcomes. We reason that the torn ligaments should heal if appropriately opposed to one another, just as they do in other anatomic areas. For example, why should it be that type III lateral ankle sprains have excellent clinical outcomes with nonoperative intervention? Is it not because of the inherent stability of the ankle joint? After a severe ligament injury, the inherent stability provided by the joint geometry and muscular forces keeps the hemorrhagic ligament ends opposed. Thus, healing is the routine outcome (Fig. 6-9). If the ankle were held in an inverted position for several weeks after an injury to the lateral ligament, this would likely not be the case. Similarly, the pull of the trapezius superiorly on the clavicle and the pull of gravity inferiorly on the arm often result in the torn AC joint ligaments having poor apposition after the injury, in many cases preventing adequate healing of the tissues (Fig. 6-10).

FIGURE 6-9 Schematic of the lateral ligamentous structures after a type III ankle sprain. Note that after the injury, the tibiotalar joint immediately reduces, thus allowing the torn ligament ends to sit directly opposed to one another and heal in this position.

FIGURE 6-10 Schematic of a type III (or higher) AC joint separation. The trapezius pulls the distal clavicle superiorly (red arrow), and gravity pulls the arm inferiorly (green arrow); thus, the torn ligament ends are NOT opposed to one another. There exists a diastasis, which prevents the appropriate healing of these ligaments.


  • A 43-year-old active male recreational athlete presented one day after injury to the shoulder. He enjoys multiple overhead sports on a regular basis.

  • He dove for a volleyball and although he made a “spectacular” play (as per his report)—he landed on the tip of his right (dominant) shoulder and knew immediately that he had suffered a significant injury to his shoulder.

Physical Exam:

  • Exam is limited secondary to pain, but he has full active and passive ROM.

  • No apparent strength deficits on cuff evaluation.

  • Obvious deformity of the AC joint with arms at rest by the side (Fig. 6-11).

  • Distal clavicle is reducible and no obvious excessive A-P instability when reduced.


  • Bilateral clavicle view demonstrates >100% displacement of the distal clavicle (Fig. 6-12).

  • MRI demonstrates significant edema within the coracoclavicular region (Fig. 6-13).

Arthroscopy Findings:

  • Intra-articular diagnostic arthroscopy revealed no pathological findings (Fig. 6-14).

  • Once the base of the coracoid is exposed, the tunnels are drilled, and the coracoid DogBone (Arthrex, Inc., Naples, FL) implant is seated underneath the coracoid (Fig. 6-15).

  • The clavicle DogBone is then placed, and the AC joint is reduced and the FiberTape sutures (Arthrex, Inc., Naples, FL) secured to complete the AC joint reduction/repair (Fig. 6-16).

FIGURE 6-11 Obvious deformity is seen at the right AC joint.

FIGURE 6-12 Bilateral 30° tilt view of the clavicles demonstrates >100% separation of the right AC joint and significant widening of the coracoclavicular distance on the right.

FIGURE 6-13 MRI demonstrated significant fluid/hemorrhage around the coracoclavicular region.

FIGURE 6-14 Diagnostic intra-articular arthroscopy revealed no rotator cuff pathology (A), normal labrum (B), and a normal biceps tendon (C). G, glenoid; H, humeral head; BT, biceps tendon.

FIGURE 6-15 The DogBone implant can be seen under the base of the coracoid. Note the subscapularis underneath the implant and that the implant is in-line or posterior to the subscapularis tendon. This implant location denotes appropriate placement of the coracoid tunnel. C, coracoid; SSc, subscapularis.

FIGURE 6-16 A: Intraoperative radiograph demonstrated appropriate placement of the coracoid and clavicle implants as well as reduction of the AC joint. B: Six-month postoperative films in the office demonstrate maintenance of the reduction of the AC joint and symmetry between bilateral AC joints.

Pearls, Pitfalls, and Decision-Making:

This case highlights the acute fixation of an AC joint separation with an isolated DogBone construct only. By reducing the joint and allowing the torn ligaments to appose one another, this patient healed uneventfully and maintained a 100% reduction of his AC joint at 6 months post-op.

The treatment of acute type III AC joint remains controversial with limited and conflicting data available in the literature to guide decision-making. Some believe very strongly that if the ligaments are still hemorrhagic, they will have a high likelihood of healing. Thus, we offer healthy and active patients isolated AC joint stabilization if the operation will be performed 2 weeks or less from the time of injury. Some of us have had consistently good to excellent results with maintenance of the reduction of the AC joint with this approach. Others of us have had more mixed results with treating grade III injuries with only DogBone reconstruction, even if performed for acute or subacute injuries. Thus, others of us have transitioned to utilizing allograft augmentation on all AC joint reconstructions.

Another pearl regarding AC joint treatment evaluation is to always get upright bilateral AC joint x-rays on a single film. As illustrated by the 6-month postoperative x-ray in this case (Fig. 6-17), if one focuses on only the right shoulder, one might incorrectly interpret the distal clavicle as being elevated. However, coracoclavicular (CC) distances of both shoulders are identical. Now notice how the nonoperative (noninjured) shoulder seems to have some elevation of the distal clavicle if one focuses only on the superior aspect of the joint. This illustrates how the radiographic appearance of the AC joint varies based on the patient’s anatomy and on the angle of the beam. Therefore, bilateral AC joint films are very beneficial and can alleviate surgeon anxiety about potential radiographic failure.

FIGURE 6-17 Six-month post-op x-ray shows how on casual inspection the right distal clavicle appears elevated in relation to the acromion. However, when comparing it to the left side, it is clear that this is the normal appearance of this patient’s AC joint on this x-ray view. The coracoclavicular distances are equal on both shoulders, thus confirming that the anatomic reduction has been maintained.


  • A 55-year-old male crashed his ATV (all-terrain vehicle) into a tree and hit his right shoulder against the tree. This occurred 1 day prior to orthopaedic evaluation.

  • No previous shoulder problems.

Physical Exam:

  • Obvious deformity of the right AC joint

  • Minimal ecchymosis or swelling (as injury was only 1 day old)

  • Normal strength on rotator cuff testing (although it does cause pain)

FIGURE 6-18 X-ray taken in the office of bilateral AC joints demonstrates a grade III AC joint separation.

FIGURE 6-19 A: Intraoperative fluoroscopy demonstrates significant elevation of the distal clavicle in relation to the acromion. This likely represents a grade V injury rather than a grade III. B: After the reduction and fixation, the clavicle looks appropriately positioned in relation to the acromion.


  • X-rays demonstrate a likely type III AC joint separation (Fig. 6-18).

Arthroscopy Findings:

  • The patient did not have any additional pathology in his shoulder on diagnostic arthroscopy.

  • DogBone fixation was performed in a standard fashion (Fig. 6-19).

Postoperative Course:

  • This patient did well postoperatively with no significant setbacks in his recovery.

  • Initial postoperative films at 2 weeks showed that the reduction was nearly anatomic (Fig. 6-20).

  • X-rays taken at the time of discharge (6 months) demonstrated that the distal clavicle had displaced further with the CC distance being almost twice that of the nonoperative side (Fig. 6-21).

  • Despite this, the patient reported that he felt that his shoulder function was almost normal, and he could not “notice” any visible difference in the two shoulders when looking in the mirror. On physical exam, the difference was indeed quite subtle.

FIGURE 6-20 X-rays in the office taken 2 weeks after repair demonstrate good alignment of the AC joint. The CC distance between the right and left shoulders is also quite similar. This constitutes a good reduction of the joint.

Pearls, Pitfalls, and Decision-Making:

If the torn AC and CC ligaments do not have a high likelihood of healing, any form of mechanical fixation is going to fail over time. As seen in this case, in the “biology versus hardware” race, the hardware fails every time if the tissues not heal appropriately. While the initial AC joint reduction was excellent postoperatively (as was the 3-month film), the AC joint had definitely separated by the final follow-up at 6 months. Interestingly, this patient was a radiographic failure, but from a clinical perspective, he was happy with the shoulder.

But why did his native ligaments not heal? Or did they heal but just were not strong enough to keep his reduction over time? The timing of his surgery was almost identical to the above acutely repaired case; however, his radiographic outcome was quite different. Perhaps age played some role in the poor outcome seen here.

FIGURE 6-21 Final 6-month postoperative film looks like there has been significant radiographic “settling” of the AC joint and has assumed the appearance of type II separation.

Another interesting conundrum in this case is why clinical failure did not accompany radiographic failure? One very favorable characteristic of the shoulder is that its large range of motion makes it quite adaptable to small changes in its biomechanics. As our techniques and tools for AC joint repair and reconstruction continue to advance, we are confident that many more patients will benefit from being treated in this fashion.


  • A 30-year-old male who is an active club tennis player fell directly onto his dominant right shoulder 3 weeks prior to his first orthopaedic evaluation. He was diagnosed with a type III AC joint separation. After a lengthy discussion regarding his treatment options, he chose not to have surgery. However, he changed his mind a few days later. Surgery was performed at 4 weeks postinjury.

Physical Exam:

  • Type III AC joint separation

  • Full active motion but pain as he elevates above 80°


  • X-rays confirmed a type III AC joint separation.

  • MRI showed no other pathology in addition to the AC joint separation.

Arthroscopic Findings:

  • Intra-articular examination showed a SLAP lesion, which was arthroscopically repaired (Fig. 6-22).

  • Arthroscopic AC joint repair with DogBone/FiberTape system (Arthrex, Inc., Naples, FL) was performed (Fig. 6-23).

  • The CA ligament was dissected off the undersurface of the acromion and the anterior deltoid and was transferred and repaired so that it was in contact with the distal clavicle (arthroscopic Weaver-Dunn procedure) (Fig. 6-24).

FIGURE 6-22 Right shoulder, posterior viewing portal. The SLAP lesion has been arthroscopically repaired. G, glenoid; BT, biceps tendon.

FIGURE 6-23 Right shoulder, anterosuperolateral viewing portal. DogBone implant is visible on the undersurface of the coracoid. C, coracoid.

FIGURE 6-24 Right shoulder, posterior subacromial viewing portal. A: The CA ligament (dashed line) is being dissected from the undersurface of the acromion and the anterior deltoid. B: The CA ligament is being transferred and will be held in contact with the undersurface of the distal clavicle by means of two suture pairs passing anterior and posterior to the prepared bone bed on the undersurface of the distal clavicle, then tied together above the distal clavicle. C, clavicle; A, acromion.

Pearls, Pitfalls, and Decision-Making:

  • This patient presented to us at 3 weeks postinjury with a type III AC joint separation, and his surgery took place almost 4 weeks postinjury. Ordinarily, for injuries up to 2 weeks old, we will reduce the AC joint with the
    DogBone/FiberTape system, bringing the torn ends of the CC ligaments into apposition so that they can heal together. After 2 weeks, we become concerned about decreased potential for primary healing of the torn ends of the ligaments, so we usually add an allograft (e.g., tibialis anterior) to enhance healing and stability. In this case, we were barely past our 2-week cut-off for primary repair versus allograft, so we elected to arthroscopically dissect and transfer the CA ligament to the undersurface of the distal clavicle as an autograft, thereby performing an arthroscopic Weaver-Dunn procedure.

  • The decision to offer surgery to this patient soon after injury was prompted by the fact that he was a competitive overhead athlete (club tennis player), and the injured shoulder was on his dominant side. We believe that overhead athletes with AC joint separations on their dominant side should be surgically repaired.

  • We always perform an arthroscopy of the glenohumeral joint when we do an AC joint repair or reconstruction because we have found that 30% of such patients have additional intra-articular pathology that needs to be addressed arthroscopically.1 This patient had a SLAP lesion that we repaired.


  • A 66-year-old male—right hand dominant avid golfer

  • 3 weeks prior, he tripped over a rope while playing golf and landed directly onto the point of the right shoulder.

  • Complains of sharp pain every time his right arm crosses midline; thus, with every golf follow-through, he has sharp pain and cannot play golf.

  • No improvement with PT or NSAIDs over the past 3 weeks.

Physical Exam:

  • Healthy active gentleman in no distress.

  • Full active and passive ROM although some motions cause AC joint pain.

  • AC joint prominence but the distal clavicle is reducible with palpation.

  • Some residual ecchymosis around the shoulder but minimal swelling.

  • Rotator cuff exam is slightly painful (around the AC joint), but the patient has normal strength in all planes.

FIGURE 6-25 Initial x-rays in the office demonstrating slightly >100% displacement of the right distal clavicle and significant widening of the coracoclavicular interval.


  • Bilateral clavicle films were obtained that demonstrated slightly >100% displacement of the distal clavicle and widening of the CC interval (Fig. 6-25).

Arthroscopy Findings:

  • The intra-articular exam revealed significant fraying of the upper subscapularis. This has been described by Dr. Stephen Snyder as the FUSSI lesion (Frayed Upper SubScapularis with Impingement) (Fig. 6-26A).

  • The FUSSI lesion is typically due to abrasion of the subscapularis tendon from anterior capsular tissue, and this offending tissue was debrided during the exposure of the rotator interval and coracoid (Fig. 6-26B).

  • The tunnels were drilled, and the coracoid DogBone implant was appropriately placed at the base of the coracoid (Fig. 6-27).

  • The FiberTape sutures were not tied until the allograft tissue had been passed underneath the coracoid and around the clavicle.

  • An Arthroflex graft (Arthrex, Inc.; Naples, FL) was prepared around a central FiberTape suture. The 15 × 140 graft was chosen. One edge of the graft was sewn to the FiberTape, and then, the graft was rolled such that the dermal side (shiny side) was outward. A suture was then wrapped around the tubular construct to hold its shape (Fig. 6-28).

  • The graft was passed anterior to the clavicle and MEDIAL to the coracoid as well as anterior to the clavicle and LATERAL to the coracoid. This was accomplished by placing a switching stick in each of these locations and dilating with a cannula inserter over top of the switching stick. The cannula inserter was left in position while a passing wire was passed through the cannula and pulled out the anterior portal (Fig. 6-29).

  • The passing wires (which are usually switched out to FiberLink sutures) are then utilized to shuttle the graft underneath the coracoid. Of note—the graft will position itself underneath the neck of the coracoid automatically, due to the concavity of the inferior coraoid (Fig. 6-30).

  • Next, one limb of the graft (preferably the medial limb as this is more anatomic) is then shuttled behind (posterior to) the clavicle. The AC joint is reduced, the clavicle DogBone attached, and FiberTapes tied. C-arm is utilized to assure appropriate reduction of the AC joint. Finally, the graft limbs are sewn to one another (via figure-8 sutures) over top of the clavicle DogBone implant (Fig. 6-31).

  • Postoperative and 6 week films demonstrate good hardware placement and excellent alignment of the AC joint (Fig. 6-32).

FIGURE 6-26 A: Diagnostic arthroscopy of the right shoulder demonstrates (as viewed from the posterior portal) significant abrasion of the upper subscapularis. This has been described as a FUSSI lesion. B: The offending capsular reflection is debrided with an arthroscopic shaver during the exposure of the rotator interval and coracoid. SSc, subscapularis; H, humeral head; BT, biceps tendon.

FIGURE 6-27 The coracoid DogBone has been placed at the base of the coracoid. The implant tilting posteriorly is evidence that the tunnel has been appropriately placed near the base. C, coracoid.

Pearls, Pitfalls, and Decision-Making:

As discussed above, when surgery occurs from between 2 and 4 weeks after the time of injury, we believe that isolated DogBone repair (without allograft reconstruction) has a higher likelihood of failure. For such subacute cases, we recommend supplementing the “biology” of the DogBone reconstruction in one of three ways: dermal allograft reconstruction (as seen in this case), arthroscopic Weaver-Dunn (as seen in the preceding case), or tendon allograft (as seen in the chronic reconstruction cases below).

The Arthroflex (Arthrex, Naples, FL) human acellular dermal allograft (nonhomologous use) should theoretically become a collagen scaffolding for CC ligament reconstruction. It is less expensive than other allograft tissue (of similar dimension), and it has excellent mechanical properties.

In this case, the allograft reconstruction worked very well with the patient having excellent radiographic (Fig. 6-33) and clinical outcomes. He returned to daily golf and was very satisfied with his result.

FIGURE 6-28 A: The ArthroFlex (AFlex150) 15 × 140 mm graft is wrapped around a FiberTape suture. B: One edge of the graft is sewn with a running suture to the FiberTape. C: The graft is then rolled such that the dermal (shiny) side is outward and another running suture is wrapped around the graft to hold its shape.

FIGURE 6-29 A: The switching stick has been passed anterior to the clavicle and medial to the coracoid in this figure. B: The second pass is anterior to the clavicle and lateral to the coracoid, and a cannula dilator is passed over top of each switching stick in order to widen the soft tissue tunnel for graft passage. C, coracoid.

FIGURE 6-30 The graft has “auto” positioned itself underneath the coracoid neck. Note that the DogBone implant is posterior to the graft since the DogBone was appropriately positioned at the base of the coracoid. C, coracoid; G, allograft.

FIGURE 6-31 The limbs of the allograft are overlapped over the top of the clavicle DogBone implant and then sewn to one another with figure-8 sutures. This is done after the joint is reduced, and the FiberTape sutures are tied over the clavicle DogBone.

FIGURE 6-32 A: Postoperative films and (B) 6-week films both demonstrate good alignment of the AC joint symmetrical to the contralateral side. The coracoclavicular distance is essentially equal on both sides.

FIGURE 6-33 Six-month postoperative film demonstrates good maintenance of the AC joint reduction.


  • A 31-year-old male who fell off a bicycle 1 year earlier and sustained a type III AC joint separation of his left shoulder.

  • He has persistent pain and weakness of the left shoulder and has been unable to resume recreational athletics.

Physical Exam:

  • Type III AC joint separation, left shoulder

  • Tender left AC joint

  • Full range of motion

  • Normal strength


  • X-rays show type III AC joint separation.

  • MRI scan suggests possible Bankart lesion.

Arthroscopic Findings:

  • A Bankart lesion was discovered and repaired with double-loaded suture anchors (Fig. 6-34).

  • Reconstruction of the CC ligaments was performed arthroscopically with a DogBone/FiberTape fixation system (Arthrex, Inc., Naples, FL) along with a tibialis anterior allograft (Fig. 6-35).

FIGURE 6-34 Bankart lesion has been repaired with suture anchors prior to the reconstruction for the AC joint reconstruction. MGHL, middle glenohumeral ligament. G, glenoid; H, humeral head.

FIGURE 6-35 The DogBone implant (Arthrex, Inc., Naples, FL) has been positioned at the junction of coracoid base and coracoid neck, adjacent to the previously passed tibialis anterior allograft. CB, coracoid base; TAA, tibialis anterior allograft.

Pearls, Pitfalls, and Decision-Making:

  • In performing a reconstruction for chronic AC separation, we believe that it is important to have a biologic graft (we prefer tibialis anterior tendon because it always has sufficient length for the C-C reconstruction as well as for reinforcement of the AC joint) in addition to a strong mechanical fixation (DogBone system) to protect the graft as it is being biologically assimilated by the body.

  • We have not found it necessary to crisscross the graft as some others have recommended. We pass the graft anterior to the clavicle, then loop it under the coracoid, then pass it posterior to the clavicle, then tension the graft, and suture the limbs of the graft together.

  • We do not like to make large holes in the coracoid or the clavicle. Therefore, we do not pass the graft through drill holes in the clavicle or in the coracoid. We have seen instances of pathologic fracture through such drill holes, and we do not believe they are necessary or desirable for graft fixation. The only bone holes that we drill are the small ones for the FiberTape that tensions between the DogBone implants.

  • The most difficult part of the procedure is passage of the graft medial to the coracoid. The passage must be directly against bone (coracoid) to help protect against neurovascular injury. Furthermore, passage of the tendon adjacent to the medial coracoid means that the graft must pass
    through the tendon of the pectoralis minor as it inserts into the coracoid. This tendon can be quite robust and difficult to pass through unless it is dilated. We have found that a very safe reliable way to pass the graft through this tendon is to pass it through an 8.25-mm clear cannula (Arthrex, Inc., Naples, FL) that is inserted over a switching stick after dilators have been passed sequentially over the switching stick to enlarge the channel. The proper position is first determined by placing a spinal needle under direct visualization just medial to the coracoid and then “walking down” a switching stick next to the needle. Once the cannula is in place, a shuttling suture is passed under the coracoid with a curved SutureLasso; this suture is used to safely shuttle the graft medial to the coracoid and then underneath the coracoid.


  • A 26-year-old male who crashed riding a dirt bike presented 4 days after initial injury stating that he was “already feeling better.”

  • Initial conservative treatment was recommended.

  • Returned 3 months later complaining of increased pain (without new injury), and he was concerned that the deformity had worsened.

Physical Exam:

  • Initial exam (at the time of injury) demonstrated slight AC joint prominence, which auto-reduced with shoulder shrug.

  • No deficits on rotator cuff or distal exam.

  • Examination at 3 months post-injury demonstrated gross deformity of the AC joint, which was reducible with palpation, however, no longer reducible with shoulder shrug exam.


  • Initial office x-ray at 4 days post injury demonstrated AC joint subluxation that was classified as type II+ (Fig. 6-36).

  • Images at his 3-month visit demonstrated worsening of the AC joint separation and increased CC distance (Fig. 6-37).

Arthroscopy Findings:

Oct 27, 2018 | Posted by in ORTHOPEDIC | Comments Off on Shoulder Separations and Other AC Joint Injuries

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