Adhesive capsulitis is a painful shoulder condition characterized by a gradual loss of
both passive and active range of motion due to inflammatory changes and eventual fibrosis
and contracture of the shoulder joint capsule. It occurs in about 2% to 5% of the
population, and a majority of patients are female. The true cause of the condition
remains unclear, however, it has been proposed that the initial synovitis stimulates the
development of a fibrotic cascade. The development of adhesive capsulitis has been
associated with diabetes mellitus, thyroid dysfunction, Dupuytrens contractures,
autoimmune diseases and treatments for certain cancers. Adhesive capsulitis progresses
through four predictable phases, defined by symptoms, physical examination, arthroscopic
appearance and biopsies.
Regardless of stage, the mainstay of treatment for adhesive capsulitis of the shoulder is
conservative, focused mainly on physical therapy combined with a home exercise program,
regardless of stage. Pharmacologic agents are often used as adjuncts to physical therapy,
and include nonsteroidal anti-inflammatory medications (NSAIDs), oral corticosteroids and
intra-articular injections of corticosteroids. Although a large percentage of patients in
the early stages of disease respond well to conservative treatments, those who fail
therapy and injections may require surgical intervention, including arthroscopy with
lysis of adhesions and/or manipulation under anesthesia.
Numerous studies have investigated the effect and success of injections combined with
standard physical therapy for adhesive capsulitis of the shoulder. In general,
intra-articular injection of corticosteroids has been found to be superior to
administration of oral cortisone and at least equivalent to manipulation under anesthesia
alone. Injections have been shown to reduce pain quicker and result in earlier return of
range of motion. Low doses of steroid appear equally as effective as higher doses.
Image-guided injections, whether ultrasound or fluoroscopic guided injections, have also
been shown to be more effective than blinded injections.
Failure of an injection and therapy to provide relief either results in a repeat
image-guided injection or surgical intervention, both of which have significant
associated cost and potential morbidity. Thus, there would be significant potential value
to a long-acting, sustained release intra-articular steroid injection for the treatment
of adhesive capsulitis of the shoulder. Zilretta®, triamcinolone acetonide extended
release suspension 32 mg, is a microsphere formulation of injectable steroid which is
FDA-approved for and has shown significant promise for the treatment of knee
osteoarthritis. This long-acting steroid could have several important advantages in the
treatment of shoulder adhesive capsulitis. It may potentiate and prolong the
anti-inflammatory effect of the steroid, and potentially avoid the need for costly
additional image-guided injections or expensive and potentially morbid surgery. An
additional potential benefit is less elevation of peripheral blood glucose in diabetics,
a known complication of traditional steroid injections that has been demonstrated to be
mitigated using a sustained release formulation.
Out primary aim in this study is to assess patient reported pain and outcomes in patients
with idiopathic adhesive capsulitis of the shoulder at 3, 6 and 12 months following
single, image guided ZILRETTA injection.