Roy Altman, Michael Fredericson, Samir K Bhattacharyya, Brad Bisson, Thomas Abbott, Sashidhar Yadalam, Myoung Kim

This study assessed the association between hyaluronic acid (HA) injections and time-to-total knee replacement (TKR) surgery for patients with knee osteoarthritis (OA). Patients 18 to 64 years of age who had TKR surgery between January 1, 2006 and December 31, 2011 were identified from the MarketScan Commercial claims database. All patients had 6 years or more of continuous enrollment prior to TKR surgery. There were two cohorts (1) patients with HA injections prior to TKR surgery and (2) patients who did not have HA injections prior to TKR surgery. Time-to-TKR was defined as the total days from the date of diagnosis of knee OA on the patient's first visit to an orthopedic surgeon to the date of TKR surgery. Results included 22,555 patients who had TKR surgery: 14,132 in the non-HA and 8,423 in the HA cohort. In this retrospective analysis of patients undergoing TKR, the median Time-to-TKR surgery was 326 days for the non-HA and 908 days for the HA cohort, a difference of 582 days. Those receiving HA injections had a median 1.6-year longer Time-to-TKR surgery versus those who did not receive HA injections. These results have both clinical and economic implications.