To Look at the Characteristics of Synovial Fluid and Cartilage Matrix in Osteoarthritic Knee After Hyaluronic Acid Injection

Quantifications of Biochemical Changes of Synovial Fluid and Cartilage Matrix in Osteoarthritic Knee After Hyaluronic Acid Injection Using Novel MRI (Magnetic Resonance Imaging) and NMR (Nuclear Magnetic Resonance) Techniques

The purpose of this study is to identify novel imaging markers for characterizing the biochemical profiles in synovial fluid and cartilage matrix in OA knee joints after intra-articular HA (Euflexxa) injection using high field NMR and MRI techniques.

We hypothesize that:

1. High-field HRMAS NMR spectroscopy will provide sensitive measures for biochemical changes within knee synovial fluid after HA injection;
2. Baseline HRMAS spectroscopy, in particular N-acetyl peaks, as well as early changes of glutamate will predict patient response of pain relief after HA injection;
3. MR cartilage T1p and T2 quantifications will provide sensitive measures for biochemical changes within knee cartilage matrix after HA injection. Specifically cartilage T1p and T2 will decrease in patients who respond to the treatment, indicating potential beneficial effects of HA injection to cartilage preservation.

Inclusion Criteria:

• Age 18 to 80 years
• Symptomatic knee OA as defined by the American College of Rheumatology criteria
• Kellgren-Lawrence grade I, II or III on prior x-rays (take within 6 months of screening visit)
• knee pain score >40 mm on a 100 mm visual analogue scale for > 15 days in the last month
• NSAIDs permitted if the dose has been stable for at least one month prior to baseline and stays stable during the study
• Have been recommended for Euflexxa treatment by physician
• Knee effusion based on clinical exam or imaging

Exclusion Criteria:

• Any contraindication to MRI (pregnancy, metallic fragments in the eyes, vascular clips, Pacemakers etc)
• History of knee replacement
• Known sensitivity or allergy to any component of Euflexxa
• Inflammatory arthritis
• Previously received viscosupplementation therapy within 6 months of study enrollment
• Intra-articular injection of corticosteroid to study joint within the past 3 months
• Arthroscopic or open surgery within the previous 12 months or planned surgery to the study joint
• Concomitant medications of oral/parenteral corticosteroids
• Morbid obesity defined as body mass index (BMI) >40 kg/m2
• Active malignancy; an active systemic infection; recent high impact or high energy trauma (clinically defined) to the study joint
• Large knee effusion based on clinical exam or imaging