Osteoarthritis becomes more prevalent with increasing age, and currently is occurring more frequently in the "baby boomer" generation (ages 44-66 years). However, many individuals may be reluctant to undergo arthroplasty procedures because potential activity limitations. Thus, physicians must consider each patient's history and desired activity level after treatment. Osteoarthritis treatments include nonoperative measures such as weight reduction, injections, and nonsteroidal anti-inflammatory drugs, as well as operative options, including partial and total knee arthroplasty. Each treatment type will vary in its impact on activity levels. If arthroplasty is required, patients must be cautioned to minimize component overload, which may result in polyethylene wear and loosening; however, cardiopulmonary fitness and general conditioning benefits of activity can be maintained.