In her college days, Jodi Lom was what many would describe as a natural athlete -- a life-long lover of sports who attended the University of California at Santa Barbara on a full-ride basketball scholarship.
At age 35, she walked with a limp and needed to use her arms to get in and out of a chair.
"I was in pain all the time," Lom says. "I couldn't even play with my kids anymore the way I wanted to."
Lom's experience may sound familiar to millions of aging Americans who feel the pain of their former athleticism. Over time, years of cumulative wear and tear take a toll on the knees, breaking down cartilage and depleting its shock-absorbing capabilities.
For Lom, the breaking point came after multiple surgeries yielded little improvement.
"At the time that I was trying to recover from the fourth knee surgery, it was right about the time I needed to teach my kids to ride bikes, so I couldn't even chase them down the bike path and hang on to their seat to hold them up so they wouldn't fall down," she says.
"That was the catalyst, really, to saying to myself that I need to get out there, go to as many doctors as I can, and find out what I can do to make myself better," she says.
In recent years, a host of new procedures have emerged to help knee-pain sufferers like Lom.
Today patients can opt for a tried-and-true artificial knee replacement, or they can choose a biologic replacement -- one that uses human tissues, some of which come from the patient's own body, to restore smooth, pain-free movement to the knee.
Other additions to the field, including a female-specific artificial knee and a synthetic lubricant that can be injected into the knee joint, further augment orthopedic surgeons' repertoires.
Lom chose to go with a biologic knee replacement, an option that Dr. Kevin Stone at the Stone Clinic in San Francisco said provides a natural-feeling result.
"That tissue becomes your own tissue, so there is nothing to come loose; there is no artificial material," said Stone, who innovated the biologic knee replacement. "The knee feels more normal, and you can run and play impact sports on it."
Stone performs the surgery by removing some of the patient's own bone tissue. He grinds this tissue to a paste, and then reinserts it into the problem area in the knee joint. This "paste graft" is thought to encourage a new blood supply, prompting the knee to actually regrow its own cartilage.
A second operation replaces the meniscus, a horseshoe-shaped cushion of cartilage that acts as a shock absorber between the upper- and lower-leg bones. Unlike the paste graft, this part of the procedure uses donor tissue.
Most in the field agree that these biologic techniques hold significant potential for the future of knee replacement. However, they say more research is needed before this procedure becomes a widely accepted alternative to traditional techniques using artificial materials.
"Many experts stress that biologic knee replacements are experimental, very preliminary and without long-term results," says ABC News Medical Editor Dr. Tim Johnson. "For serious knee problems, the traditional knee replacement is still the gold standard."
Not all the new developments in knee surgery involve natural tissues. One new synthetic offering is a female-friendly knee joint -- designed to cater to America's 37 million aging women. Proponents say its slender shape and more flexible range of movement is a better fit for females.
"The gender knee was designed because ... the female knee is narrower and the knee cap moves differently than the male knee," said Dr. Giles Scuderi at Lenox Hill Hospital in New York City who designed one such device.
Some experts, however, remain skeptical about this female-friendly knee.
"What the companies are attempting to do is make knee replacements with different shapes that might better fit people (women among them) whose anatomy is slightly different," said Dr. William Hozack, president of the American Association of Hip and Knee Surgeons and professor of orthopedic surgery at Jefferson Medical College in Philadelphia.
"That the companies are choosing to market to women is just that -- a marketing campaign," he said.
Another synthetic option lets people avoid surgery altogether. In a procedure called viscosupplementation, doctors inject a synthetic gel into the knee to lubricate the joint and alleviate pain -- if only for a while.
"[Viscosupplementation] helps about 25-30 percent of patients for a period of months to one year," said Dr. Allen Boyd Jr., division chief of adult reconstructive surgery at the University of Rochester in Rochester, N.Y. "Its effectiveness is relatively poor."
Still, for many like Lom, any relief from knee pain represents a major lifestyle enhancement -- and possibly even a return to the athletic exploits of years past.
"I have been able to compete again, which is huge for my mental health, and fun for my kids to watch," she said.
"I have been able to ride horses again -- which is my passion -- and I just competed in a triathlon, which is a blast," she said. "I loved it, I loved it. I'm addicted."