Indications

Rockwood type I and II AC injuries should be treated nonoperatively, with the expectation of excellent short- to midterm results.7 In the event that late, symptomatic AC arthrosis occurs, elective distal clavicle excision can predictably relieve pain and restore function.8 Nonoperative management can also be performed on type III AC dislocations, as the collective weight of evidence reveals no benefit from surgical treatment9,10; however, some authors believe that the overhead throwing athlete and manual laborer should undergo reconstruction, which is also the bias of the senior author of this chapter.11,12

Reductions, Casting Techniques, and Orthoses

Ice should be provided in the acute setting to relieve pain and swelling, and a sling is useful for support of the upper extremity against gravity. There is no benefit to closed reduction because the joint cannot be maintained in a reduced position with any orthosis, including a figure-of-eight sling.

Rehabilitation

A sling may be used for 2 to 3 weeks to support the extremity during the acute phase of pain if the patient desires. Function is advanced as discomfort allows. Shorter or longer periods with relative rest are required according to the severity of the sprain or dislocation. Patient reassurance is necessary during months of resolving symptoms.

Indications

Surgical reconstruction is indicated in patients with Rock-wood type IV to VI AC injuries to prevent chronic dysfunction and pain. The management of type III injuries remains controversial. Most experts recommend nonoperative management, whereas others believe that overhead throwing athletes and manual laborers should undergo operative treatment for Rockwood type III AC injuries.11–16

Surgical Anatomy

Fusion of the secondary ossification centers about the AC joint occurs at around 17 years of age for the acromial portion and 24 years of age for the distal clavicle. The average size of the joint is 9 × 19 mm. Branches of the axillary, suprascapular, and lateral pectoral nerves innervate the AC joint.5 Urist10 found that the clavicle slightly overrides the acromion process half the time, and that 21% of AC joints are incongruent. The lateral clavicular facet actually underrides the acromion 3% of the time.11 Knowledge of individual variation is helpful during diagnostic and surgical interpretation of anatomy. The AC joint capsule is strongest at its superior and posterior margin. The scapula is suspended from the clavicle via the CC ligaments, consisting of the well-defined trapezoid and conoid ligaments. These structures run from the base of the coracoid to the undersurface of the clavicle. The trapezoid ligament spans from the coracoid base just lateral to the conoid ligament. These strong ligaments provide restraint against clavicular elevation.

Surgical Techniques

Many surgical procedures have been described to repair an AC dislocation. The strategies have included fixing the distal clavicle directly to the acromion, augmenting the CC ligaments, or both. Though each strategy can be employed in the acute or delayed setting, if a late reconstruction is done, it is usually combined with a distal clavicle resection.

The most widely known historical procedure is that described by Weaver and Dunn,17 in which the CA ligament is transferred through the end of a resected distal clavicle. Today, some surgeons prefer either allograft or autograft tendon reconstructions to replace the CC ligaments. In either case, fixation across the AC joint or into the coracoid base is often added to augment the soft tissue repair during healing. One potential problem related to mobilization of the CA ligament is the concept of superior escape of the humeral head. The CA ligament may indeed play a role in containing the concentricity of the humeral head.18–20

The Hook Plate (Synthes, Paoli, PA) has become an increasingly popular option for AC joint dislocations.21–25 The plate is fixed to the cephalad border of the distal clavicle, and a terminal hook sweeps under the acromion so the clavicle is restrained from springing superiorly (Fig. 13.1). This can be employed alone or in conjunction with CC ligament augmentation. It is recommended that the plate be removed at 3 to 4 months after surgery to prevent known complications of acromial osteolysis and possibly acromial fracture22,26–28 and impingement.29,30 An attempt to repair the AC joint as well as the CC ligaments should augment the use of the Hook Plate.

The same procedures have been employed for distal clavicle fractures, specifically those in which the shaft displaces superiorly due to ruptured CC ligaments (Fig. 13.2). The fixation and repair challenges of distal clavicle fractures, regarding maintaining reduction, are similar to the surgical challenges of AC dislocations due to the deforming force of the sternocleidomastoid muscle on the proximal clavicle shaft. However, in the case of distal clavicle, eventual bony union helps to maintain reduction after plate removal.

Incisions

A 6-cm incision centered over the anterior edge of the distal clavicle is made to expose the dislocated AC joint. The incision is made in Langer′s lines, and thus is vertically oriented, enabling direct exposure of the torn ligaments and an adequate exposure of the coracoid. The flaps between the deltoid and trapezius are carefully developed for later closure of the deltotrapezial tissue plane. After the distal clavicle and AC joint are exposed, the torn AC joint capsule is debrided. The articular integrity is evaluated, and if there are pieces of detached articular cartilage, they are removed. In the acute setting, the clavicle should be noted to reduce rather readily by an inferior directed force on it (in a type III injury), or pistoning the arm cephalad to meet the clavicle. The CC ligaments are then inspected for integrity, with the intention of repairing them if possible, but only after fixation of the AC joint.

If the surgeon elects to retain the distal clavicle, as in the acute AC disruption, a drill hole is made in the clavicle adjacent to where the native CC ligament attaches. Mersilene tape is then passed along the base of the coracoid under the conjoint tendon and anterior to the hook-shaped coracoid, then up through the drill hole in the clavicle, and sutured securely after reduction. The nonabsorbable synthetic tape is preferable to heavy suture due to the increased likelihood of “cutting out” the drill hole with suture, although certainly, given the strong deforming forces, the tape has been described as cutting through as well. The CC ligaments are then sutured primarily. Though the Hook Plate can be used in this scenario as well (Fig. 13.3), another way to enhance fixation is with the addition of a screw from the superior clavicle down into the coracoid base. A 6.5-mm partially threaded screw is used for this purpose, so that with the lag effect, the Mersilene tape is offloaded. As mentioned before, it is the our preference to plan for elective removal of the hardware, and this is done at approximately 3 months postoperatively, after CC ligament healing.

In the case of a symptomatic chronic dislocation, arthritic joint, or comminuted distal clavicle, the surgeon should perform a distal clavicle resection and subsequent reconstruction of the CC ligaments. The clavicle is simply cut back from its distal end to the area of insertion of the CC ligaments, about 1.5 cm proximal on the bone. The distal clavicle is prepared by opening and smoothing the exit point of the medullary canal, and a slightly more proximal hole is drilled in the cephalad surface of the clavicle. The CA ligament is then detached from its insertion on the acromion, and a No. 2 braided suture is passed in a Krackow or modified Bunnell technique through the end of the clavicle up through the drill hole, where it is then sutured as a loop around the distal resected clavicle. Again, this procedure can be augmented with the hardware options described above.

Rehabilitation

Patients undergoing surgical reconstruction of AC injuries should be protected in a sling for 4 to 6 weeks. Passive range of motion (PROM) exercises should be encouraged over this time period, but pushing, pulling, or reaching activities are not permitted to allow for deltoid reattachment. Active range of motion (AROM) may commence at 6 weeks postoperatively, and strengthening exercises at 8 weeks. Contact sports may be initiated at 16 to 20 weeks postoperatively and after hardware removal when this option is utilized.31

New Techniques

Video 13.1 Acute Type III AC Joint Separation

A new suture-button construct called the Tightrope (Arthrex, Naples, FL) is being used by some surgeons for fixation.23,32–35 It provides fixation between the coracoid process and the clavicle, which can be performed arthroscopically or through a mini-open approach. Another potential benefit is reducing the need for implant removal (Fig. 13.4). Although it has the advantage of not crossing the AC joint, it has been associated with fractures of the coracoid.

Indications

Isolated and minimally displaced scapula fractures should be treated expectantly. Treatment has emphasized symptom relief and early motion. In fact, because the shoulder is such a mobile joint, it can tolerate moderate displacement quite well, although the limits of tolerable displacement are not well identified in clinical studies. After motion is restored in the first 4 to 6 weeks, therapy is directed at rehabilitating the rotator cuff and strengthening the parascapular musculature. Because more than 80 to 90% of scapula fractures are minimally displaced, this noninvasive approach is effective for most of these fractures.42,43,57–64 Indications for surgery are becoming better accepted, as it seems clear that severe displacement, as described below, is associated with symptoms of stiffness, pain, and dys-function as evidenced by subsets of patients in many studies who have fared poorly.43,57,65–69

Displacement of the scapula is difficult to describe, both anatomically and with respect to the functional consequences. Clearly, significant displacement is better tolerated in some patterns of scapula fractures than in others. For example, the same amount of displacement may have different implications depending on whether it is the scapula body, neck, or glenoid. It is helpful to think in terms of extra-articular and intra-articular fractures. Regarding intra-articular fractures, a superior glenoid fracture in the horizontal plane, such as the Ideberg grade II, which often exits inferior and medial to the coracoid, is a more stable pattern than a posterior or anterior glenoid fracture of the same size, due to the implications for shoulder instability. Thus, a surgeon may be less inclined to operate in the situation where the glenohumeral joint will likely remain stable despite some degree of articular stepoff. Regarding scapular neck fractures, if a fracture enters the spinoglenoid notch, then the glenoid is more unstable than if it exits the spine of the scapula medial to the acromion base. Furthermore, a fracture exiting the scapular spine may be more unstable than a fracture exiting the medial vertebral border of the scapula. These implications are not well understood, and clearly there are different deforming forces on each fragment depending on where fractures enter and exit. Consider the forces from the levator scapula, the rhomboids, and latissimus as they interact on fragments depending on where fractures relate to insertions of these muscles. These nuances may influence slightly the indications for operative intervention based on a surgeon′s interpretation of relative stability in each situation.

Reduction and Casting Techniques and Functional Bracing

There is no known or identified role for closed reduction or casting. No brace has proven to be efficacious for scapula fractures.

Rehabilitation

If the scapula fracture is treated nonoperatively, a 2-week period of immobility while the arm is supported with a sling is appropriate. Active mobility of the elbow and wrist are encouraged in the immediate phase to reduce swelling. After this, the patient should begin passive motion, advancing to a full range as symptoms allow. It is helpful to begin with pendulum exercises and increase the PROM under the guidance of a therapist.

The patient should be taught to use the uninvolved extremity to assist with exercises. Scapula fractures will heal rapidly due to a well-endowed blood supply. Therefore, AROM can be started at 4 weeks and maximized quickly. Resistive exercises are begun by 8 weeks, and restrictions lifted (including weight bearing) as symptoms allow by 3 months.

Indications

Displaced articular fractures of the glenoid are the clearest and most accepted indication for surgery. Although some studies recommend initial displacement of between 2 to 10 mm,49,70,71 we recommend 4 mm of step or gap as an appropriate indication for surgery72,73 (Fig. 13.7a,b). If humeral head subluxation, early arthrosis, and a poor outcome are to be prevented, open reduction and internal fixation (ORIF) should be performed.41,58,72,74 (Fig. 13.8).

Displaced fractures of the scapula neck should be treated operatively if displacement or angulation causes functional imbalance of the parascapular musculature. There is no agreement as to the exact definition of a neck fracture, but the variant entering lateral to the acromion base is most unstable; however, the variant entering medial to the acromion base, when displaced and angulated, can still be highly problematic.65 Though the original contemporary surgical recommendations by Ada and Miller43 included a medially displaced glenoid more than 9 mm or 40 degrees of angular displacement of the neck and body, more recent recommendations have allowed for more displacement, and are based on the interpretation of results from larger clinical series. We recommend considering operative intervention if relative displacement between the lateral border of the scapula and the glenoid exceeds 20 mm, or the lateral border angular deformity exceeds 45 degrees (Fig. 13.7c–f). Simultaneous displacements of > 15 mm and 30 degrees of angulation are also an indication that multiple planes of deformity should be considered.73,75

Perhaps the greatest amount of information correlating poor outcome with malunion relates to the deformity in the coronal plane, described as the glenopolar angle (GPA). This is the angle between vectors drawn from the inferior to superior edge of the glenoid, and then from the superior glenoid to the inferior body on an AP scapula view (Fig. 13.7c,d). Multiple studies show an association between poor outcome and a GPA < 20 degrees.66,69,76,77 We use 22 degrees as our indication, but also obtain an opposite-shoulder AP radiograph to compare to the normal side.

Double disruption of the superior shoulder suspensory complex (SSSC) is another indication for surgical treatment of scapula fractures. The SSSC is an osseoligamentous ring made up of the glenoid, coracoid, and acromion processes, as well as the distal clavicle, the AC joint, and the CC ligaments.59 The superior strut is the middle clavicle, and the inferior strut is the neck of the scapula. Lesions to two or more of these structures theoretically destabilize the shoulder and create the “floating shoulder” lesion. Stabilization of one or both lesions has been recommended to restore integrity to the SSSC, thereby preserving its function of maintaining a stable relationship between the upper extremity and axial skeleton and providing a firm attachment for the many soft tissues that enable shoulder function.78

Our approach to these double lesions is to restore integrity of the SSSC with ORIF of both lesions (i.e., clavicle and scapula) if each are displaced greater than 1 cm (Fig. 13.9). We use an opposite shoulder AP radiograph and a computed tomography (CT) scan to make such a determination. One can be misled by a single AP X-ray of the injured shoulder because the glenoid may be significantly displaced and angulated, making it impossible to get a “true” AP view of the glenohumeral joint perpendicular to the normal plane of the scapula. Wijdicks et al79 demonstrated that whereas a clear view through the glenohumeral joint is used as the criteria for determining a true AP, even subtle rotation of the shoulder can affect measurements significantly.

The operative indications for performing open reduction and fixation of extra-articular scapula fractures can be summarized as follows:

1. 
   

   Lateral border displacement (medialization) of > 2 cm

   
   
2. 
   

   Angulation as determined by a scapula-Y view of > 45 degrees

   
   
3. 
   

   Medialization and angulation of > 15 mm and 30 degrees, respectively

   
   
4. 
   

   A glenopolar angle of < 20 degrees

   
   
5. 
   

   Displacement of a clavicle and scapula fracture of > 1 cm (or complete disruption of an AC joint)

   
   
6. 
   

   Intra-articular stepoff or gap of the glenoid > 4 mm

These indications are based on measurement techniques shown in Fig. 13.7 . These criteria are not absolute and must be placed in the context of the patient′s age, comorbidities, activity demands, and extremity dominance.

Other extra-articular fractures that require ORIF include displaced fractures of the scapular spine, coracoid, and acromion processes. Process fractures carry a poor prognosis when treated nonoperatively.30,57,60–62,80,81 Anavian et al81 published the largest combined series of scapula process fractures, detailing an indication for surgery of a centimeter of displacement to prevent malunion and nonunion, inclusive of techniques for fixation. If the acromion fracture heals in a caudad position, causing encroachment into the subacromial space, impingement can become a major problem, so at times surgery of the acromion may be indicated even is lesser displacements. This angular displacement must be taken into consideration.

Surgical Anatomy

The scapula is approximately flat and triangular, with a thin translucent body, surrounded by borders that are well developed because of their positions as muscular origins and insertions. When fractured, landmarks are a bit harder to appreciate because predictable deforming vectors are at work based on muscular forces (Fig. 13.10). The scapular spine divides the superior and inferior angles of the scapula, thus forming the supraspinatus and infraspinatus fossae, which are origins for their respectively named muscles (Fig. 13.11). Its concave anterior surface serves as a broad origin for the subscapularis muscle.

The spine of the scapula ends laterally as the acromion, which arches over the humeral head from which it is separated by the rotator cuff and subacromial bursa. Along with the clavicle, it serves as the origin of the deltoid muscle. The trapezius also originates on the acromion and scapular spine anteriorly. The medial border of the scapula is the site of attachment of the serratus anterior, which functions during scapula protraction, and the rhomboid muscles, which assist with scapular retraction. The levator scapulae muscle inserts on the superior medial border and is specifically named for its function. The lateral border of the scapula sweeps up from the inferior angle, forming a thick condensation of bone that ends in the neck of the scapula. The lateral border is the site of origin of the teres major and minor muscles, as well as the insertion for the long head of the triceps on the neck and part of the latissimus dorsi at the inferior angle. The coracoid process is a curved osseous projection medial to the anterior neck of the scapula, which serves as the origin for the CC and CA ligaments as well as for the coracobrachialis, short head of the biceps, and pectoralis minor muscles. Just above the coracoid process on the superior margin of the scapula is the scapular incisura, traversed by the transverse scapular ligament, above which lays the suprascapular artery and below which runs the same nerve.

The pear-shaped glenoid fossa lies at the lateral angle of the scapula, its peripheral margin covered by a fibrocartilaginous labrum that is confluent above with the long head of the biceps tendon at the supraglenoid tubercle. The labrum increases the depth of the glenoid by 50%.63 The glenoid fossa is approximately 39 mm in a superior-inferior direction and 29 mm in an anterior-posterior direction in its lower half, which is 20% wider than the top half.64

The scapula is part of the superior shoulder suspensory mechanism, which attaches the upper extremity to the axial skeleton by the clavicle. Eighteen muscle origins and insertions on the scapula aid in its function to provide a stable base from which glenohumeral mobility can occur.82

Surgical Techniques

Video 13.2 ORIF Scapula Posterior Approach

Logical operative approaches should provide adequate exposure of the fracture, add as little structural damage as possible, and take into account the restorative capacity of the biological repair process.83 Most scapula fractures are best operated by some modification of the posterior approach of Judet or the anterior deltopectoral approach.

Posterior Approach

Positioning

The patient is placed in the lateral decubitus position, “flopping” slightly forward for better access to the posterior shoulder. An axillary roll must be appropriately positioned. Arm rests, towels, or specially designed positioning bumps should support the extremity in 90 degrees of forward flexion and slight abduction (Fig. 13.12). The entire upper extremity and forequarter should be prepped and draped to allow manipulation of the shoulder. Manipulation after fixation in delayed fractures is important to overcome the contractures. From a posterior view, the prep should include patient′s neck superiorly, the vertebral column medially, and the latissimus fold caudally.

Incisions

The key to a successful surgical incision is accurate palpation of the bony landmarks of the acromial spine and vertebral border of the scapula. The prominent posterolateral acromion is palpated and followed medially to the base of the spine of the scapula, and then caudad along the vertebral (medial) border. It is very helpful to manually protract and retract the scapula by grabbing the arm and “shucking” it medially and laterally to create scapulothoracic excursion. This enables the surgeon to feel the vertebral border as it is indirectly manipulated. Note that the incision makes an acute angle at the superomedial corner of the scapula.

A Judet posterior incision is planned using these landmarks, with the horizontal limb 1 cm caudad/distal to the scapular spine and the vertical limb 1 cm lateral to the scapular vertebral border. This adjustment places the scar off the prominent bony border for better plate coverage and enables lateral retraction of a slightly less voluminous flap.

The incision is made through subcutaneous tissue and then directly down onto the bony ridge of the scapula spine around to the medial angle and down the vertebral scapular border. For access to the lateral border of the scapula, the incision must be sufficiently generous to facilitate flap retraction. Properly executed, the fascial incision along the acromial spine and medial border should yield a cuff of tissue to suture back to its bony origin at the end of the procedure if the posterior musculature is elevated (Fig. 13.13).

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