Serum and Synovium Protease Inhibitor Levels in Primary and Secondary Osteoarthritic Joints

This is a single institution observational study. Pre-procedure diagnosis: Based on chart review and consultation with operating surgeon of subjects undergoing total knee arthroplasty, patients will be grouped into primary or secondary (PTOA) osteoarthritis groups. Primary osteoarthritis will be identified through a clinical presentation of generalized osteoarthritis with possible bilateral involvement and no identifiable trauma or overuse to knee joint. Secondary osteoarthritis will be identified by history of overuse or trauma to the afflicted knee and a clinical presentation that in general lacks symmetrical involvement and/or severity, PTOA. On the date of surgery, both primary and secondary groups will have 2 cc whole blood collected via venipuncture during placement of intravenous access for anesthesia. No additional venipuncture is necessary and this study necessitates no instrumentation/manipulation of patient beyond that of IV access normally obtained preoperatively. Blood will then be placed in refrigerated storage (2-6 C) until analyzed for A2M assay. On the date of surgery, joint aspirate from both primary and secondary groups will be collected by the operating surgeon during knee arthroplasty. At the time of arthrotomy, joint fluid that is expressed from surgical site will be harvested and placed into an eppendorf tube and placed on ice. The study incurs no further risk to the patient and no further instrumentation/manipulation for synovial fluid harvest that is beyond the risk or instrumentation/manipulation of the indicated surgical procedure. Joint aspirates will then be stored until A2M assay.