Abstract
The shoulder is a girdle consisting of four articulations: the glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic. These articulations are supported by muscles, tendons, and ligaments. Fractures, sprains, dislocations, and soft tissue tearing are all common ways to injure the shoulder. This chapter outlines the evaluation and management of clavicle fracture, proximal humerus fracture, glenohumeral dislocation, AC separation, and acute rotator cuff sprain/tear.
Keywords
acute shoulder injury, AC sprain, clavicle, dislocation, humerus fracture, rotator cuff, separation
1
What is the differential diagnosis for an acute shoulder injury?
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A thorough differential is dependent on an understanding of shoulder anatomy. The shoulder is a girdle consisting of four articulations: glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic. These articulations are supported by muscles, tendons, and ligaments.
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Fractures, sprains, dislocations, and soft tissue tearing are all common ways to injure the shoulder.
- •
The focus of this chapter will be to outline the evaluation and management of clavicle fracture, proximal humerus fracture, glenohumeral dislocation, AC separation, and acute rotator cuff sprain/tear.
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In a young patient with a direct fall onto the shoulder, the most common injuries are AC separation and clavicle fracture.
2
What imaging is useful for the acutely injured shoulder?
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Typical x-ray views for any acute shoulder injury include a standard AP, true AP, and axillary view.
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Additional views may be useful if certain injuries are suspected. This will be described in more detail later in the chapter.
Case: A 24-year-old hockey player is skating mid-ice and collides with a player from the opposing team. He loses his balance and falls on his right shoulder. He gets up and skates to the bench, where he complains to his athletic trainer of right anterior shoulder pain. He tries to lift his arm forward and has significant pain.
1
What is the differential diagnosis for an acute shoulder injury?
- •
A thorough differential is dependent on an understanding of shoulder anatomy. The shoulder is a girdle consisting of four articulations: glenohumeral, acromioclavicular, sternoclavicular, and scapulothoracic. These articulations are supported by muscles, tendons, and ligaments.
- •
Fractures, sprains, dislocations, and soft tissue tearing are all common ways to injure the shoulder.
- •
The focus of this chapter will be to outline the evaluation and management of clavicle fracture, proximal humerus fracture, glenohumeral dislocation, AC separation, and acute rotator cuff sprain/tear.
- •
In a young patient with a direct fall onto the shoulder, the most common injuries are AC separation and clavicle fracture.
2
What imaging is useful for the acutely injured shoulder?
- •
Typical x-ray views for any acute shoulder injury include a standard AP, true AP, and axillary view.
- •
Additional views may be useful if certain injuries are suspected. This will be described in more detail later in the chapter.
Case: A 24-year-old hockey player is skating mid-ice and collides with a player from the opposing team. He loses his balance and falls on his right shoulder. He gets up and skates to the bench, where he complains to his athletic trainer of right anterior shoulder pain. He tries to lift his arm forward and has significant pain.
Rotator Cuff Tear
9
What is the common presentation of an acute rotator cuff tear?
Patients will complain of pain and weakness with overhead and reaching activities following trauma or high demand use.
10
What are the exam findings?
The most common finding is weakness with abduction (supraspinatus tear). Weakness with internal or external rotation would indicate subscapularis or infraspinatus/teres minor tear, respectively.
11
What special tests are helpful?
Supraspinatus: positive drop arm. Infraspinatus: positive external rotation lag sign. Subscapularis: positive lift-off test. Teres minor: positive horn blowers.
12
What imaging tests are useful?
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Standard shoulder series x-rays are recommended to rule out bony abnormalities. MRI or ultrasound can provide a definitive diagnosis.
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It is important for the clinician to be aware that partial rotator cuff tearing is a common finding in older asymptomatic patients.
13
Is there a way to clinically differentiate complete versus partial tears?
Rotator cuff tears exist on a spectrum from partial to full width and from partial to full thickness and may involve one or more tendons ( Fig. 37.3 ). As such, there is no perfect test. The described special tests can be useful in identifying tears that are large enough to cause substantial weakness. If pain interferes with the exam, a subacromial lidocaine injection followed by repeat exam can allow pain-free muscle activation. Be aware that injections of lidocaine may result in a false-positive tear or bursitis seen on subsequent MRI if done shortly after the injection due to the iatrogenic introduction of fluid.
