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cells were placed into culture and treated with either radiation or a chemotherapy drug. Seven mice received injections of senescent cells, and seven received injections of nonsenescent cells that were grown parallel in culture. Mice that received injections of senescent cells developed many of the hallmarks of OA, including pain in the knee joint and decreased joint functionality. Narrowing of the joint space, loss of bone near the knee joint and bony spurs were also observed on X-ray. The animals that received injections of nonsenescent cells exhibited no significant OA-related changes. In addition, pathologic changes associated with OA were observed in histological samples taken from mice that received the senescent cell injection. A NEW APPROACH TO OA? The study's results reveal that the accumulation of senescent cells in joints is indeed causal for OA, according to Dr. Kirkland. Based on these results, treating OA with drugs that target senescent cells may help slow progression of the disease, a condition for which there are no approved disease-modifying drugs. Senolytic drugs — a new class of pharmaceutical agents that were developed in 2015 and help destroy and remove senescent cells — may hold the key to treating age-related OA. Moving forward, research that tests whether or not senolytic drugs help prevent, delay or treat OA in animal models is necessary. If animal trials are positive, clinical trials in humans will likely follow, according to Dr. Kirkland. Current OA treatment strategies are not curative. They include weight loss, physical therapy, and the use of nonsteroidal anti- inflammatory medications, corticosteroid injections, braces and/ or assistive devices. In cases of end-stage, or bone-on-bone, OA, joint replacement surgery may be recommended. Due to advances in surgical technique and implant technology, joint replacement is a safe and long-lasting solution for hip and knee OA. However, joint replacement surgery is often used more discriminately and may not be as e¢ective in treating OA in other joints, such as the ankle. Ankle implants, for example, usually last only 10 years in ideal scenarios. Disease-modifying, senolytic agents may be an important complement for OA treatment, especially in joints that may not respond as well to surgery. "We have excellent surgical treatment strategies that are very successful and relieve pain, improve function, and get people back to work and back to their lives ...," Dr. Lajam says. "However, there's always room for improvement, and we're continuing as orthopedic surgeons to look for those. ... We hope in the future that we will have some even better solutions." ■ " There is a whole lot we don't know about the development and progression of osteoarthritis. These studies ... that look at the causal factors will allow us to develop disease-modifying agents in the future [that] will be really life-altering for millions of people. There's a lot of research to be done that could potentially have a great impact on the disease." A. HOLLY JOHNSON, MD, INSTRUCTOR IN ORTHOPEDIC SURGERY AT HARVARD MEDICAL SCHOOL, FOOT AND ANKLE SURGEON AT MASSACHUSETTS GENERAL HOSPITAL Let us help you spend less time manag ing your medical practice so you can spend more time with your family. Consulting • Coding • Billing 16170 Jones Mal tsbe rge r Rd. S ui te 10 6 , S an A ntonio, Texas 78247 concordispm.com • (210) 704-1014 M D N E W S . C O M /// M D N E W S S A N A N T O N I O ■ 2 017 1 5