The shoulder provides one of the largest ranges of motion of all the joints in the musculoskeletal system. This is due partly to the morphology of the glenohumeral joint (the humeral head is much larger than the glenoid) and partly to additional motion provided by the claviculoscapular complex. Loss of shoulder motion (shoulder stiffness) may have a major impact on the ability to perform desired activities. Shoulder stiffness may be the consequence of multiple injuries or conditions. Understanding the factors that contribute to loss of shoulder motion is essential to properly manage shoulder stiffness. This chapter provides some general principles related to the various conditions that can lead to shoulder stiffness, provides some basic science information on biomechanics and pathophysiology, and then reviews primary shoulder stiffness and secondary shoulder stiffness.
Definition and classification of shoulder stiffness
Shoulder stiffness is defined as loss of passive range of motion in one or more planes. Many conditions leading to shoulder stiffness are associated with loss of motion in several planes (elevation, abduction, internal rotation, external rotation), although the degree of motion loss may vary for each plane, and occasionally there may be limited motion in only one plane.
There is some confusion regarding the terminology used to describe the various presentations of shoulder stiffness. The term frozen shoulder implies loss of shoulder motion in all planes ( Box 17.1 ). Frozen shoulder is considered primary when associated underlying pathology cannot be identified in the shoulder joint, and secondary (or acquired ) when capsular fibrosis restricting motion develops after fractures or other traumatic injuries, after surgery, or after other conditions (rotator cuff disease). The term adhesive capsulitis is often used to refer to primary frozen shoulder . Primary frozen shoulder has been found to be particularly prevalent in individuals with certain conditions when compared with the general population ( Box 17.2 ); when none of these conditions can be identified, patients are diagnosed with idiopathic primary frozen shoulder ( idiopathic adhesive capsulitis). The term systemic frozen shoulder has been used by some when any of the conditions in Box 17.2 are identified in association with frozen shoulder.
Frozen shoulder
Primary frozen shoulder (adhesive capsulitis)
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Systemic (diabetes mellitus, thyroid disorders, etc.)
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Idiopathic
Secondary frozen shoulder
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Posttraumatic
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Postoperative
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Other (in the setting of calcific tendonitis, cuff tears, etc.)
Other causes of shoulder stiffness
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Degenerative or inflammatory arthritis
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Heterotopic ossification
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Spasticity
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Septic arthritis and osteomyelitis
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Other
Hormonal/homeostatic
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Diabetes mellitus
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Thyroid (both hypothyroidism and hyperthyroidism)
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Adrenocorticotropic hormone deficiency
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Hyperlipidemia (triglycerides and/or cholesterol)
Cardiac
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Cardiac surgery
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Ischemic heart disease
Neurologic
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Stroke
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Parkinson disease
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Neurosurgery (especially acute aneurysm surgery)
Trauma (without fracture, dislocation, or cuff tear)
Drug induced or related
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Matrix metalloproteinase inhibitor for gastric carcinoma
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Antiretrovirals
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Fluoroquinolones
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Pneumococcal vaccine
Associated fibrotic conditions
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Dupuytren disease
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LaPeyronie disease
Other
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Chronic obstructive pulmonary disease
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Radical neck dissection
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Malignancy
Primary frozen shoulder
Primary frozen shoulder is defined as a condition in which patients experience progressive loss of active and passive motion in all planes, with various degrees of pain, in the absence of other pathologic conditions that may also lead to stiffness. As detailed later, the primary pathologic finding combines synovitis and capsular fibrosis of the glenohumeral joint. In most patients, the condition courses in three sequential phases. The initial freezing or painful phase is characterized by insidious progressive onset of pain and stiffness. Typically, at the beginning, pain is felt only at night or with activities, but eventually pain is constant. Although pain most often precedes stiffness, in a few patients stiffness is the first symptom. The average duration of the freezing phase has been reported to range between 10 and 36 weeks. In the second frozen or stiff phase, pain subsides a little and stiffness plateaus; this phase seems to range in duration between 4 and 10 months. The last phase of thawing or recovery leads to gradual spontaneous improvement of both pain and motion. The average duration of all three phases is 30 months.
For a patient presenting with a main complaint of shoulder stiffness and pain to be diagnosed with primary frozen shoulder, it is accepted that (1) the physical examination findings must confirm loss of passive motion in more than one plane (elevation, external rotation, and internal rotation) and (2) imaging studies must exclude other causes of stiffness (glenohumeral arthritis, inflammatory arthritis, full-thickness rotator cuff tears, and other). A challenging situation may occur when patients present with loss of passive motion and pain, normal radiographs, and magnetic resonance signal change involving the labrum or rotator cuff; it can be extremely difficult to determine if these individuals have secondary frozen shoulder complicating a partial-thickness cuff tear or a labral tear, or whether on the contrary these imaging findings are incidental because they are so common in the general population. The same may apply when there is radiographic evidence of calcifying tendonitis.
Along the history of orthopedic surgery, several attempts have been made to define primary frozen shoulder. Codman used the term frozen shoulder to describe a clinical pattern of muscle spasms and glenohumeral stiffness. He stated that this condition was “difficult to define, difficult to treat, and difficult to explain from the point of view of pathology.” Neviaser used the term adhesive capsulitis to refer to “a chronic inflammatory process involving the capsule of the shoulder causing a thickening and contracture of this structure which secondarily becomes adherent to the humeral head.” At a symposium sponsored by the American Academy of Orthopedic Surgeons in 1992, a workshop committee defined frozen shoulder as “a condition of uncertain etiology characterized by significant restriction of both active and passive shoulder motion that occurs in the absence of a known intrinsic shoulder disorder.” Zuckerman and Rokito published a summary of the consensus efforts of 190 shoulder experts from around the world. Frozen shoulder was defined as “a condition characterized by functional restriction of both active and passive shoulder motion for which radiographs of the glenohumeral joint are essentially unremarkable except for the possible presence of osteopenia or calcific tendonitis.” In that consensus, secondary frozen shoulder was classified as intrinsic (due to rotator cuff or biceps pathology), extrinsic (due to an abnormality remote to the shoulder), or systemic (when it occurs in the patients with diabetes mellitus or thyroid disorders). However, only 66% of the experts agreed on this classification scheme. We continue to favor the classification scheme outlined in Box 17.1 .
Secondary frozen shoulder
Secondary frozen shoulder is defined as the development of restriction of shoulder motion in the presence of other shoulder pathology. Secondary frozen shoulder is most commonly seen after surgery for rotator cuff repair or labral repair, and after trauma. Classifying secondary frozen shoulder is challenging because, in some conditions, capsular fibrosis clearly is the main contributor to loss of motion (as when stiffness develops after repair of the superior labrum), whereas in other conditions loss of motion may be mostly secondary to other abnormalities (e.g., loss of motion after a proximal humerus fractures may be due to a combination of malunion and capsular fibrosis). Secondary frozen shoulder may be classified in three general categories: posttraumatic shoulder stiffness, postsurgical shoulder stiffness, and other conditions that lead to acquired shoulder stiffness (see Box 17.1 ).
Posttraumatic shoulder stiffness
Occasionally, frozen shoulder may develop after a relatively minor injury; when that is the case, many surgeons would consider the patient to have developed primary frozen shoulder. Posttraumatic shoulder stiffness refers to stiffness after more substantial traumatic injuries that result in fracture or dislocation. The classic example is represented by proximal humerus fractures. As mentioned, a main goal in the evaluation of these patients is to understand how much of their shoulder stiffness is due to capsular contracture versus other abnormalities that may impair motion.
Postoperative shoulder stiffness
Any shoulder procedure may be complicated with postoperative stiffness. The most common procedures that can lead to postoperative stiffness include repair of superior labral tears, instability surgery, rotator cuff repair, fracture fixation, and shoulder arthroplasty. Although stiffness after some of these procedures may respond to isolated release of the contracture, in some others it may be necessary to address other factors to restore motion fully (revision of one or more components in shoulder arthroplasty, correction of malunion, or posttraumatic osteoarthritis after fracture internal fixation, etc.).
Other conditions leading to acquired shoulder stiffness
Multiple other conditions may be associated with acquired stiffness, including rotator cuff disease or calcific tendonitis. Conceptually, other conditions that lead to shoulder stiffness secondary to structural damage beyond capsular fibrosis could be lumped in this category, but because they typically require a completely different treatment strategy, they do not purely represent secondary frozen shoulder. These conditions include degenerative or inflammatory arthritis and other less common conditions such as septic arthritis with or without osteomyelitis, heterotopic ossification, and neuromuscular disorders leading to spasticity; scapular conditions may also lead to acquired shoulder stiffness.
Biomechanics of normal and abnormal shoulder motion
Evaluation and management of patients presenting with shoulder stiffness as their main complaint, secondary to any of the conditions mentioned earlier, require an understanding of the biomechanics of normal shoulder motion. To position the hand in space without restrictions, motion must occur at all the joints involved, including the glenohumeral articulation, the sternoclavicular articulation, the acromioclavicular articulation, the scapulothoracic interface, and the subacromial-subdeltoid interface.
Glenohumeral joint
The glenohumeral joint provides a remarkable range of motion. The larger spherical humeral head moves with little constraints on the smaller and relatively flat glenoid. In addition, the capsule of the glenohumeral joint is very capacious and remains loose except at the terminal ends of motion. The normal surface area of the capsule is nearly twice the surface area of the humeral head. When the torsional resistance of the normal, intact glenohumeral joint capsule has been measured, the capsule has been shown to be lax until the terminal range of motion is reached ( Fig. 17.1 ). The humeral head rotates and translates in reference to the glenoid articular surface. The glenohumeral joint capsule and its ligamentous reinforcements act as restraints to both rotation and translation at the end of range of motion.
