The purpose of this study is to determine whether a longer duration, controlled, sustained release dexamethasone delivery system would be more effective in helping patients with osteoarthritis reduce their pain, remain functional, and delay their need for knee replacement.

The objectives of the study are to assess the dexamethasone delivery system for:

• Safety and tolerability
• Efficacy

Formal statistical analysis to compare treatment groups will not be performed due to the small number of participants in this pilot study. Summary statistics will be assessed using the short form of the knee injury and osteoarthritis outcome score (KOOS JR) surveys and questionnaires to assess pain intensity, pain medication consumption and wound assessment.

Inclusion Criteria

• Male or female ≥ 40 years of age at time of consent
• Diagnosis of unilateral or bilateral knee osteoarthritis for at least 6 months prior to screening with confirmation of osteoarthritis according to the American College of Rheumatology Criteria for Classification of Idiopathic Osteoarthritis of the Knee (clinical and radiological) based on an X-ray performed within 6 months prior to screening or during the screening period
• Kellgren - Lawrence grade ≥2 on weight bearing anteroposterior femorotibial radiograph performed within 6 months prior to or during screening period
• Mean score of ≥ 5 and ≤ 10 on the 24 hour average pain score (0 - 10 Numeric Rating System) during the screening period
• Body mass index (BMI) ≤ 40 kg/m2
• Willingness and ability to comply with the study procedures and visit schedules and ability to follow verbal and written instructions
• Willingness to stop all pain medications except acetaminophen and paracetamol 14 days prior to implantation

Exclusion Criteria:

• Fibromyalgia, chronic pain syndrome, or other concurrent medical or arthritic conditions which could interfere with the evaluation of the index knee
• History of inflammatory arthritis including rheumatoid arthritis, juvenile inflammatory arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, reactive arthritis
• Hemophilia
• Achondroplasia
• History of infection in the index joint
• Intra-articular corticosteroid (investigational or marketed) in any joint within three months of screening
• Intra-articular hyaluronic acid (investigational or marketed) in the index knee within three months of screening
• Oral, inhaled, and intranasal corticosteroids (investigational or marketed) within one month of screening
• Prior arthroscopic or open surgery of the index knee within 12 months of screening
• Planned / anticipated surgery of the index knee during the study period
• Active or history of malignancy within the last five years, with the exception of resected basal cell carcinoma, squamous cell carcinoma of the skin, or resected cervical atypia or carcinoma in situ
• Insulin dependent diabetes
• History of or active Cushing's syndrome
• Skin breakdown at index knee where procedure would take place
• Women of child-bearing potential
• Case history related to motor vehicle accident or workers compensation
• Presence of hardware in the index knee (e.g. screws, plates)
• Immunocompromised patients (TB, HIV, etc.)
• Allergic reactions to acetaminophen and paracetamol