Intra-articular Doxycycline: A Novel Treatment of Adhesive Capsulitis

Overview

We will recruit a total of 40 patients from the Vanderbilt Sports Medicine Clinics who have been diagnosed with adhesive capsulitis and have not undergone any previous treatment. The 40 patients will be randomized, with 20 in the control group of 3 intra-articular injections of 40mg Methylprednisolone spaced every two weeks, and 20 in the experimental group of 3 intra-articular injection of 50mg doxycycline spaced every two weeks. Both groups will begin a standardized physical therapy program within a pain-free range of motion 4 weeks after the initiation of treatment. We will prospectively follow patients for one year, with follow-up at 6 weeks, 12 weeks, 6 months, and 12 months after the initiation of treatment. Outcomes will be measured using the American Shoulder and Elbow Score (ASES) and objective measurements of shoulder range of motion, which will be collected by the treating physician. Both the patients and physicians participating in the study will be blinded.

Adhesive capsulitis, also known as frozen shoulder, is a common condition of the shoulder joint affecting 2-5% of the adult population and characterized by progressive, painful loss of both passive and active range of motion of shoulder \[1,2\]. Individuals affected by this condition find it increasingly difficult to perform activities of daily living that require overhead movement or rotation of the affected shoulder. The natural history of frozen shoulder follows a predictable progression of symptoms, lasting from 9-24 months before complete resolution, and results in significant loss of productivity and quality of life for those affected \[3\]. Despite the significant number of patients affected by adhesive capsulitis and the extensive literature focused on the progression and natural history of the condition, the true underlying etiology remains poorly understood. In light of this poor understanding of the condition, it is not surprising that a number of conservative and invasive modalities exist as accepted treatments. These include non-steroidal anti-inflammatory drugs (NSAIDS), oral steroids, intra-articular steroid injections, Physical Therapy (PT), and benign neglect as well as more invasive treatments such as hydroxylation, manipulation under anesthesia, and arthroscopic capsular release \[2\]. These treatments have all be shown to have short-term benefit in pain relief, but none have proven to be superior nor alter the long-term natural history of adhesive capsulitis. Over the past decade, however, there has been a growing body of literature suggesting that Propionibacterium acnes infection may play a significant role in a variety of pathological conditions affecting the native shoulder, most notably frozen shoulder \[4,5\]. Our goal is to employ a treatment strategy focused on eradicating P acnes infection as a conservative treatment of adhesive capsulitis. Through this project, we aim to complete a prospective randomized pilot study to examine the hypothesis that administration of intra-articular antibiotics effective against P acnes will prove to be a superior treatment of adhesive capsulitis as compared to current gold standard of intraarticular steroid injection.