The relationship between knee arthroscopy and arthroplasty in patients under 65 years of age.

A private payer database was used to examine the incidence and rates of knee arthroscopy in patients less than 65 years of age and the subsequent risk of knee arthroplasty. Time to event analysis was performed using the Kaplan-Meier method; also, Cox regression analysis was used to evaluate the relative risk of subsequent knee arthroplasty for arthroscopic patients. Overall, 247,034 knee arthroscopies, done for injury or arthropathy, were identified between 2004 and 2009. Within 1-year of arthroscopy, 2.2% of arthropathy patients and 0.9% of injury patients underwent a knee arthroplasty. These increased to 5.2% and 2.4% at 5-years, respectively. The risk of arthroplasty following arthroscopy increased significantly with age. Further study is warranted to examine the benefit of arthroscopy in younger patients with OA.