'Good Morning America' Co-Anchor Lara Spencer Opens Up About Hip Replacement

— -- “Good Morning America” co-anchor Lara Spencer was starting to feel the aches and pains that are common after decades of active living.

“I love sports, I love being active, I love challenging myself,” said Spencer, 47. “I was a jock growing up from the time I could walk.”

Spencer’s nagging pain in her right hip, however, led to a surprising diagnosis. Spencer, who was a competitive diver at Penn State and now plays tennis, was told by her doctor she needs a hip replacement.

“It was so upsetting,” Spencer said of the diagnosis. “I waited for a long time before I did anything about it or told anyone because it sounds like it’s an old person’s problem and I just couldn't believe it.”

Spencer’s physician, Dr. Peter Moley, told ABC News that around 10 percent of all hip replacements are done on patients in Spencer’s age group, under 50 years old. Spencer also has hip dysplasia in the soon-to-be-replaced hip, which made her cartilage more likely to wear down earlier in life.

“So that's a huge amount of patients in that age group we don't really hear about as much,” said Moley, a physiatrist at the Hospital for Special Surgery in New York.

Spencer said she has accepted that the wear and tear to her hip came from being a “great athlete.” She said she is now focusing on getting in the best shape she can so she can have the best recovery possible.

“I was like, okay, I’m going to approach this like any other sport in my life,” she said. “I’m going to kill it.”

Spencer is scheduled to undergo the surgery this Saturday. She said today on "GMA" that she is "terrified" of having the surgery and was at first embarrassed to share the news.

"It was embarrassing to share and then I realized there is nothing to be embarrassed about," she said. "I have a genetic predisposition for this but if you're athletic and you move, it's happening younger and younger."

ABC News Chief Women's Health Correspondent Dr. Jennifer Ashton said Spencer's fears about undergoing hip replacement surgery are an "appropriate reaction" to undergoing a medical procedure.

Ashton also it was likely "only a matter of time" before Spencer needed a hip replacement, regardless of her active lifestyle.

"No orthopedic surgeon, no physician, no one in the sports world or medical world would say, 'Don't be active,'" she said. "Now if Lara earned her living seated and didn’t participate in any sports, yes she wouldn’t have been feeling this in her 40s but in some cases it’s only a matter of time."

Spencer said she has reached the point where her doctor warned her she would have back and possibly knee problems if she did not replace her hip. She also described the chronic pain she has dealt with as a result of her hip.

"There is no ignoring it at this point," she said of the pain. "I just want to say anybody out there who suffers with chronic pain, I feel you. It takes over your life. It affects you emotionally, mentally, physically. You cannot sleep. It’s hard to think about. It’s gnawing at you all the time."

"What I wish I would have done is just taken care of this sooner and spoken up," Spencer added.

Ashton said Spencer can expect to be weight-bearing and walking on the day of her surgery. The typical rehabilitation period for a hip replacement is three to six months, according to Ashton.