Adhesive capsulitis, also more generally referred to as “frozen shoulder,” describes a pathologic process marked by early shoulder pain and gradual loss of passive and active gleno-humeral motion. Primary adhesive capsulitis describes the idiopathic presentation of these symptoms, while secondary causes can develop as a consequence of trauma, infection, or other pain-generating shoulder conditions.
Adhesive capsulitis is a slowly developing condition. Gradually, over a period of months, patients develop shoulder pain. This pain is often unrelated to physical activity, and may occur at night, disrupting normal sleep patterns. Loss of motion commonly develops, and then replaces symptoms of pain, leading to functional disability. (Insert clinical picture of an individual with unilateral loss of external rotation) During the “frozen” stage, patients may complain of stiffness with rotational movements. Patients may complain of difficulty doing over-head hygienic practices (such as washing or combing hair and shaving) or toileting.
On physical exam, patients may lack focal areas of tenderness. Unique to this diagnosis, individuals with adhesive capsulitis have decreased passive and active shoulder motions. Rotational deficits tend to occur initially, followed by global motion involvement.
Early presentation of adhesive capsulitis, which has pain as its principal symptom, can be challenging to diagnose. For this reason, the diagnosis of early adhesive capsulitis is often made retrospectively, after symptoms of stiffness begin to predominate. Nocturnal shoulder pain can also be caused by infectious or neoplastic conditions.
The prototypical patient affected with primary adhesive capsulitis is a woman age 40 to 60 years. Approximately 2%-5% of the population will develop adhesive capsulitis, more commonly in the non-dominant shoulder; symptoms will develop in the contralateral shoulder 20%-30% of the time. Additionally, adhesive capsulitis is associated with endocrinopathies (most commonly thyroid disease and diabetes), cardiovascular disease, and the treatment of breast cancer. Patients with diabetes do not generally respond as well to treatment, leading to a worse prognosis than for other patients.
Pathology and pathophysiology
Primary adhesive capsulitis occurs idiopathically, leading to a scarred gleno-humeral capsule and the generation of intra-articular adhesions. The progression of scarring and adhesions decreases functional joint volume, and physically tethers the joint capsule to surrounding bone and tissues. This leads to mechanical limitations that prevent normal arcs of motion. Histologically, early adhesive capsulitis is dominated by synovitic inflammation. (insert arthroscopic photograph of inflamed synovium) With disease progression, this is replaced with diffuse fibrosis of the shoulder capsule.
Many shoulder pathologies can generate shoulder pain and symptoms similar to all stages of adhesive capsulitis. Specifically, similar pain distribution can occur with rotator cuff disease, calcific tendonitis, gleno-humeral or acromio-clavicular arthritis, or cervical strain and/or radiculopathy. Additionally, these pathologies may more solely limit active shoulder motion as a consequence of pain. As the cause of stiffness in these clinical situations is not intrinsic to the shoulder capsule, treatment is focused on the specific etiology of each condition.
By definition, the etiology of primary adhesive capsulitis is unknown. An autoimmune process that was once theorized to be linked with the development of adhesive capsulitis has never clinically or biologically established.
Radiographic and laboratory findings
Aside from excluding other shoulder pathologic conditions, radiographic imaging tends to have little role in the diagnosis of adhesive capsulitis. Isolated adhesive capsulitis will have normal radiographic findings. MRI may demonstrate capsular thickening and decreased axillary pouch filling.
Risk factors and prevention
As primary adhesive capsulitis is idiopathic, no true risk factors exist. Adhesive capsulitis does occur more commonly in women, and the associations that exist with some endocrine and cardiovascular disease are poorly understood.
The mainstay of treatment for primary adhesive capsulitis includes a multitude of non-surgical interventions. Adhesive capsulitis is a self-limiting disease. Benign neglect, although an option, is usually poorly tolerated. Due to the protracted course of adhesive capsulitis, which can take 2 years to resolve, many patients are unsatisfied with this lengthy period of pain and disability.
- The most commonly employed treatment for adhesive capsulitis is physical therapy. This is utilized to prevent soft-tissue contracture as well as to improve shoulder motion. Supporting evidence for the incorporation of physical therapy to treat adhesive capsulitis is predominantly low-level.
- Pharmacologic intervention is often included as empiric treatment in conjunction with therapy. Oral non-steroidal anti-inflammatory drugs (NSAIDs) and oral steroids may be given to decrease capsule inflammation and help modulate shoulder pain. Intra-articular steroid injections may better optimize local concentrations of medicine, and serve a similar purpose as its oral counterparts.
- Suprascapular nerve blocks have been attempted for pain relief. Advocates have suggested that disruption of pain signaling pathways may allow for a “resetting” of the pathologic processes responsible for adhesive capsulitis.
- Manipulation under anesthesia (MUA) is another commonly practiced, but poorly supported intervention for treatment of adhesive capsulitis. With a goal of physically disrupting motion-limiting adhesions, MUA is often incorporated with surgery, as treatment for patients unresponsive to conservative management.
- Hydrodilution offers a minimally invasive non-surgical alternative for arthroscopic or open surgery. Also known as “Brisement,” through the injection of intra-articular fluid, the capsule can be ruptured in an effort to disrupt adhesions and improve shoulder motion.
- The most popular surgical treatment for adhesive capsulitis is arthroscopic capsular release; however, there is little high-level evidence to support this treatment. Arthroscopic treatment can aid with disease staging and may also identify other unrecognized pathology contributed to disease symptoms. Specifically, the rotator cuff interval and posterior capsule may be incised to increase external and internal motion, respectively. This is done to remove contracted motion-limiting tissue.
- Open surgical treatment exists as an option, but is rarely done due the additional complications inherent with open procedures.
Although adhesive capsulitis is a self-limiting disease, analysis of the long-term consequence of benign neglect is equivocal. At worst, 50% of patients may continue to demonstrate either shoulder pain and/or stiffness at 7-year follow-up. A more recent review with 9-year follow-up, however, revealed that 94% of patients had normal motion and shoulder function.
- Despite widespread use of physical therapy for the treatment of adhesive capsulitis, little evidence supports it use. A Cochrane database review was unable to confirm its benefit as a treatment. Level I evidence similarly has shown no benefit, while retrospective level IV evidence has demonstrated 90% of patients treated with a multi-directional stretching program were satisfied with their clinical result.
- Treatment with oral medication has no high-level evidence supporting its use for treatment of adhesive capsulitis. A level II study has demonstrated that a 4-week regimen of naproxen or indomethicin had similar success for lowering pain levels. Risks of NSAID use include GI distress.
- Two level I studies have examined oral steroid treatment. Neither investigation demonstrated any long-term benefits in pain or motion compared with placebo. Several level I studies have evaluated intra-articular steroid injection. General trends from these studies seem to suggest that injection has more short-term pain relief, but it is largely unsustainable compared with placebo treatment. A recent level I study showed that although both treatments led to significant pain reduction and motion improvement, steroid injection led to superior results compared with oral steroids. Injection also avoids the systemic side effects of oral steroid use.
- Studies evaluating nerve block and hydrodilution are few in number. More evidence is required before routine use should be implemented in treatment of adhesive capsulitis.
- Isolated MUA is a more historic choice for failed conservative management. This particular treatment has the specific potential complication of humerus fracture. One level I study compared MUA with physical therapy, with both treatments showing similar improvement in shoulder motion. Several retrospective reviews have demonstrated more prolonged success, especially with patients specifically failing conservative measurements.
- Arthroscopic surgery is the most popular treatment for adhesive capsulitis, and it is routinely done following prolonged failure of other conservative measures. MUA is often included after releases are performed. Timelines are inexact, but surgery may be reasonable after 4 to 6 months of conservative treatment. Only low-level studies document the benefits of arthroscopic treatment. Additionally, controversy exists regarding which components of the capsule should be routinely excised. Regardless, arthroscopic treatment likely leads to less pain and quicker return of motion compared with open surgical alternatives.
“Brisement” is French for “breaking up” or “tearing.”
Adhesive capsulitis, frozen shoulder, stiff shoulder, capsule
Skills and competencies
- Recognize adhesive capsulitis and distinguish it clinically by history and physical exam from other common shoulder pathologies.
- Describe treatment options, both conservative and operative, for management of adhesive capsulitis.
- Understand the risks and benefits of these different treatment modalities.