eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Rotator Cuff Injuries

Author: Eileen C Quintana, MD, Assistant Professor, Departments of Pediatrics and Emergency Medicine, St Christopher's Hospital for Children
Coauthor(s): Richard H Sinert, DO, Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center
Contributor Information and Disclosures

Updated: Apr 15, 2009

Introduction

Background

Rotator cuff injuries are problems commonly encountered in athletic and nonathletic patients. Symptoms include pain, weakness, and decreased range of motion. Early diagnosis is important for identifying causes, implementing effective treatment, and preventing further injury.

Pathophysiology

Knowledge of the mechanical and normal anatomical structure allows for understanding of rotator cuff injuries (see Rotator Cuff Pathology). The rotator cuff muscles are the supraspinatus, infraspinatus, subscapularis, and teres minor.

Microscopically, all of the tendons of the rotator cuff fuse to form one continuous band, which is composed of a 5-layer structure. Because of this structure, none of the individual muscles have a higher incidence of tear, per se. However, the joint-side portion of the supraspinatus tendon is more susceptible to mechanical failure than the bursal side.

Most of the tears of the cuff are the result of chronic degeneration, which makes them susceptible to rupture. The chronic deterioration of the cuff results from the coracoacromial arch, which is composed of the bony acromion, the coracoacromial ligament, and coracoid process. Because of its position above the rotator cuff, the coracoacromial arch forms the roof through which the supraspinatus tendon must pass (ie, supraspinatus outlet). Repetitive microtrauma and anatomical variations lead to most of the rotator cuff injuries.

• Stage I - Edema and hemorrhage, affecting persons younger than 25 years
• Stage II - Fibrosis and tendinitis, affecting persons aged 25-40 years
• Stage III - Tears of cuff, affecting persons older than 50 years

Frequency

United States

The precise incidence of symptomatic rotator cuff injuries is not known. Many individuals with full-thickness cuff tears are not only asymptomatic but they have minimal functional disability. The most accepted figure is 20-30%. Cadaver studies of elderly persons have estimated full-thickness tears as high as 30%.¹

Mortality/Morbidity

An estimated 4% of cuff ruptures develop a cuff arthropathy. Various authors report a rate of success with conservative treatment ranging from 33-90%, with longer recovery time in older patients. Surgery results in improved function regardless of the patient's age.^2,3,4

Age

Rotator cuff injuries and tears usually do not occur in persons younger than 40 years (5-30%). The great majority is found in persons aged 55-85 years. Approximately 15% of patients with shoulder pain who are older than 70 years have rotator cuff injuries.¹

• Prevalence increases with age.¹
• Younger patients are more likely to have rotator cuff dysfunction because of overuse, subtle instability, and muscle imbalance.
• Older patients tend to have chronic shoulder pain and degeneration.

Clinical

History

Assess any patient with shoulder pain with respect to the patient's age and occupation. Characterize pain according to its duration of onset, location, radiation, timing, and quality. In addition, investigate pain for its relationship to activities and sport.

• Pain is the most common symptom encountered with rotator cuff injury.
  • Pain usually is located anterolaterally and superiorly and referred to the level of the deltoid insertion with full-thickness tears.
  • Pain is aggravated in activities where the arm must be in an overhead or a forward-flexed position.
  • In an acute injury, pain suddenly is elicited after a fall, after lifting of a heavy object, or even after a trivial amount of force.
• Following pain, weakness and limitation of motion are the next most common symptoms of a rotator cuff tear.
• The patient also may complain of clicking, catching, stiffness, and crepitus.

Physical

Approach the shoulder examination systematically in every patient with inspection, palpation, range of motion, strength testing, neurologic assessment, and performances of special shoulder tests. Also, include evaluation of the cervical spine and upper extremity.

• Inspect for scars, color, edema, deformities, muscle atrophy, and asymmetry.
• Palpate the bony and soft-tissue structures, noting any areas of tenderness.
  • The subdeltoid and subacromial bursae can be palpated anteriorly under the acromion, and laterally with the deltoid muscle and the arm in extension.
  • The supraspinatus is palpated anteriorly when the arm is externally rotated and flexed.
  • Hyperextension permits the palpation of the infraspinatus.
• Assess active and passive range of motion. Note any pain elicited and loss of motion.
  • Determine muscle strength.
  • The supraspinatus is isolated with the arm forward 90 degrees in the scapular plane and the forearm rotated into pronation (ie, thumbs down). If drooping of this position occurs, full-thickness rotator cuff tears are suggested.
  • The subscapularis may be tested with the arm at the side with internal rotation resistance. However, this can produce false-negative results; instead, place the arm internally rotated with the dorsum on the buttock surface and actively lift the hand from the buttocks against resistance.
  • The external rotators, teres minor, and infraspinatus can be tested with the arm on the side and in 90 degrees of abduction.
• Neer impingement test: An injection of 1% lidocaine into the subacromial bursae, using the lateral or posterior approach, creates signs of relief on forward flexion in patients with rotator cuff disease, distinguishing cuff disease from other sources of shoulder pain. However, rotator cuff tears are not distinguished from early stages of inflammation or fibrosis.

Causes

An emerging consensus suggests that the etiology of rotator cuff disease is multifactorial. Extrinsic factors exist, such as the morphology of the coracoacromial arch, tensile overload, repetitive use, and kinematics abnormalities. Intrinsic factors also exist, such as altered tendon vascular supply, microstructural collagen fiber abnormalities, and regional variations.

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