Bump skiers, rejoice! A total knee replacement may not be your fate. More orthopedic surgeons are performing partial knee replacements, also known as unicompartmental knee arthroplasty (UKA) or "uniknee," which are less invasive. Osteoarthritis of the knees, caused by wear and tear, is incredibly common in skiers. "In many cases, the arthritis will progress to the point that the cartilage in the knee joint is all but gone and the bones are grinding against each other," says Dr. Kevin Plancher, a leading sports orthopedist in the New York metropolitan area. Until recently, these patients were faced with one option: having all the bone and tissue cut away and replaced with a prosthetic joint. But, according to the Arthritis Foundation, about 30 percent of people with osteoarthritis have disease that affects only one compartment of the knee. And in recent years, doctors have begun replacing only the damaged compartment, resulting in quicker recovery, less pain, better joint functioning and better range of motion than a knee that has been completely replaced. Moguls, however, are still not recommended.