Introduction

• AC joint disorders are among the most common causes of shoulder pain.

• Disorders involving this joint are often confused with other glenohumeral problems.

• The AC joint is susceptible to traumatic injury as well as a degenerative process from overuse.

• Successful treatment of AC disorders relies on an accurate diagnosis obtained through a detailed history, thorough physical examination, and a complete radiographic evaluation.

• For traumatic disorders, proper classification of the injury type will aid the clinician in employing a proper treatment algorithm.

• The majority of AC separations, including Grade III disorders, are usually successfully treated with a nonoperative program.

• High-grade AC separation (types IV, V VI) and occasionally those occurring in the overhead throwing athlete can be expected to have a successful outcome following a "three-in-one" surgical reconstruction.

Figure 26-1 Ligamentous structures of the acromioclavicular joint: acromioclavicular, coracoclavicular, and coracoacromial ligaments. (Adapted from Hawkins RJ, Bell SB, Lippitt LH: Atlas of Shoulder Surgery. Philadelphia, Mosby, 1996.)

Figure 26-1 Ligamentous structures of the acromioclavicular joint: acromioclavicular, coracoclavicular, and coracoacromial ligaments. (Adapted from Hawkins RJ, Bell SB, Lippitt LH: Atlas of Shoulder Surgery. Philadelphia, Mosby, 1996.)

motion may cause repetitive stress on the AC joint in the follow-through phase with horizontal cross-arm adduction. Weight lifters will often have excessive force on the AC joint with a bench press. This has been strongly implicated in the destruction of the articular cartilage. Cahill4 reported 46 patients who were athletes, none of whom had an acute injury, but 45 lifted weights as part of their training.

Physical Examination

A complete physical examination should be performed, as described in Chapter 16, when evaluating disorders of the AC joint. In chronic disorders, there will frequently be a deformity secondary to a clavicle osteophyte or capsular hypertrophy. For acute injuries, the patient should be examined either standing or sitting since gravity tends to accentuate a deformity (Fig. 263). In these cases, the extent of the deformity may initially appear less severe because of acute soft-tissue swelling. Tender

Figure 26-2 Direct trauma resulting in acromioclavicular joint injury.

ness at the AC joint will often be elicited by direct palpation in both acute and chronic disorders. The range of motion of the shoulder may often be restricted secondary to AC pain. In both chronic and traumatic disorders, provocative maneuvers such as forced horizontal adduction will create pain.

In acute injuries, it is important to assess joint stability by gently applying pressure to the mid-clavicular area and evaluating motion in the superoinferior plane. Pain created by inferior traction to the affected extremity will be a common finding in high-grade AC separations. Each type of AC injury presents with a pattern of common findings on examination, including swelling and displacement. Type I injuries are characterized by minimal joint tenderness and swelling. There is no palpable displacement and pain is typically minimal. In type II injuries, superior displacement of the clavicle from the acromion can be seen and pain at the AC joint is common. Palpation of the CC interspace is not typically painful.

Figure 26-3 "Tenting" of the skin following acute acromioclavicular trauma.

Patients with type III injuries often present with the arm in adduction close to the body to limit pain in the AC joint. The distal portion of the clavicle may provide tenting of the skin from displacement. Pain is increased with abduction, and most motion will be uncomfortable. Unlike type II injuries, palpation of the AC joint, CC interspace, and superolateral clavicle produces pain. If the injured arm is adducted across the body, clavicular displacement becomes prominent from medial displacement of the acromion.

Type IV injuries often present like a more painful type III injury, with the additional pathology of trapezius puncture from a posteriorly displaced distal clavicle. On occasion, the clavicular displacement is extensive and tenting can be seen in the skin on the posterior aspect of the shoulder. In type IV injuries, the clavicle is often fixed posteriorly and difficult to manually reduce, causing pain.

Type V injuries are also like type III injuries, but they are characteristically denoted by severe deformity of the AC joint, often reflected by considerable drooping of the extremity compared to the contralateral normal side. Soft-tissue damage and clavicular displacement can cause significant pain, especially at the distal portion of the clavicle. A type V AC separation can often be difficult to differentiate from a type III injury. In both cases, the clavicle is high riding in relationship to the acromion. However, in a type V AC separation, the clavicle is often irreducible in relationship to the acromion even when the scapula and upper arm are manually elevated. The inability to reduce the clavicle is due to penetration through the deltotrapezial fascia, which can create a fixed deformity.

Type VI injuries are usually caused by acute trauma to the joint, such as a motor vehicle accident, and concomitant injuries should be suspected. This subcoracoid dislocation is often associated with neurovascular injury, of which paresthesias should be relieved with reduction of the dislocation. It should be noted that in each of the higher grade AC separations (types IV V and VI), all have some component of a fixed deformity that results in a poor outcome with nonoperative management.

Radiographic Evaluation

Accurate diagnosis is essential for the proper treatment of AC disorders. At a minimum, three radiographic views are required in most shoulder evaluations to ensure an adequate evaluation. The patient should be standing or sitting to fully appreciate any joint deformity. Radiographs of the affected shoulder are taken both perpendicular and parallel to the separation plane, along with an axillary view with the affected shoulder in 20 to 40 degrees of abduction (Fig. 26-4). Films should be taken at 50% intensity compared to those for investigating glenohumeral injury to avoid overpenetration. It is often beneficial to obtain a fourth view where the x-ray beam is angled 15 degrees in a cephalad direction.5 This will eliminate the scapular spine superimposition of the AC joint in the anteroposterior radiograph (Fig. 26-5). These views should be used to assess for degenerative changes including joint space narrowing, translucency, cyst and/or osteophyte formation, and any accompanying deformity. In acute injuries, particular attention should be paid to assessing for fractures or any abnormal relationship of the clavicle to the acromion.

For traumatic injuries, weighted AP stress views of both joints obtained by attaching a 10- to 15-pound weight to the wrists while the patient is standing have been recommended to help differentiate between a partial or complete disruption. However, Bossart et al6 demonstrated the lack of efficacy of this study. We have subsequently discontinued using this technique. Instead, we found that adding an anteroposterior radiograph with the arm adducted across the body and supported with the unaffected arm, as described by Basamania (unpublished data, 2006), provides more information regarding the instability of the injury. In grossly unstable joints, the acromion will slide medially under the distal end of the clavicle (Fig. 26-6).

Injury Classification

Two systems have been popularized for the classification of AC joint injuries. Tossy et al7 proposed the division of AC injuries into three distinct groups. Type I injuries involve sprain of the AC ligaments, with no involvement of the CC ligaments. Type II injuries involve complete AC ligament rupture with sprain/partial tearing of the CC ligaments. Type III injuries require rupture of both the AC and CC ligaments and are therefore the most severe.

Rockwood and Young8 further divided the type III injuries from the Tossy et al system in order to classify the more severe injuries in terms of severity and clinical outcome (Table 26-1).

Characteristic radiographic appearance for each AC injury type depends on injury severity. Use of the normal contralateral is necessary in all cases. Type I injuries show little radiographic change in joint space and no visible deformity. Type II injuries exhibit an increase in CC interval, typically less than 25% compared to normal. In type III injuries, the clavicle is superiorly displaced compared to the acromion, with between a 25% and 100% increase in the CC interval. If the clavicle is displaced 25% to 100% of clavicular width, but a concurrent increase in CC interval is not found, then a coracoid fracture should be suspected. Type IV injuries show posterior clavicular displacement compared to the acromion, most often seen on the axillary view. Type V injury characteristically reveals greater than 100% increase in CC interval. Severe displacement of the AC joint is also seen, extending two to three times the clavicular width. A type VI injury is rare; typical radiographs reveal a clavicle displaced inferior to the coracoid.

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Cure Tennis Elbow Without Surgery

Cure Tennis Elbow Without Surgery

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