(Cameron Cottrill for The Washington Post)

As she rose from the dinner table one night in February 2016, Annie Karp winced as she felt a penetrating ache deep in her hips. Unable to straighten up for a minute or two, she took small steps toward the medicine chest in her parents’ Florida home in search of an over-the-counter painkiller. Karp assumed she had pulled several muscles during an overzealous workout earlier in the day.

For the next 11 months, the ache never went away, no matter what Karp tried. Sitting was especially painful, and she began dreading the multiple daily car trips required to shuttle her two children to their activities.

Karp consulted six doctors, none of whom could find an explanation for the constant pain, which sometimes migrated to her pelvis.

“After a while, I just stopped taking about it,” recalled the 41-year-old self-employed human resources consultant, who lives in Clarksburg, Md. “No one wants a whiner or a complainer.” The pain was wearing and worrying, but never unbearable. Karp decided to stop bouncing from specialist to specialist and focus instead on learning to live with it.

But when the seventh doctor she had seen in eight months told her what he’d found, Karp was elated, even though his solution was an arduous treatment.

(The Washington Post)

“I was just so happy to have an answer,” she said.

‘Perfectly normal’

Karp has always been athletic. She began ballet lessons at age 3, was on the dance team in high school where she routinely performed splits, taught aerobics in college and even met her husband at a gym. She continued to love running and dancing, although she stopped ballet training at 15. Karp said her hip joints were unusually flexible but had never caused her pain, even though they would briefly lock periodically.

A few weeks after the Florida episode, Karp saw a Maryland orthopedist who specializes in hip problems. She told him that her mother had had both hips replaced in her 60s. The doctor did not order an X-ray, but he did watch her walk, then pronounced her hips to be “perfectly normal.” He suggested she see a spine specialist.

The spine specialist, after conducting a brief exam, found nothing.

In April, after the pain radiated from her hip bones to her pelvis and she experienced spotting between periods, Karp saw her gynecologist. An MRI scan of her abdomen and pelvis revealed a benign ruptured ovarian cyst. The gynecologist told her that the pain should dissipate soon.

When it didn’t, Karp began the first of 15 visits to a chiropractor. He performed adjustments to realign her spine, which didn’t help.

The Karps live in Clarksburg, Md. with their two kids Sasha and Jonah. (Courtesy of Annie Karp)

In May, she consulted her internist. He ordered a raft of blood tests, all of which were normal except for the level of cortisol, a stress hormone, which was slightly elevated. The internist didn’t think it was significant and told Karp her hips looked normal. He suspected her pain might be gynecologic.

“At that point, we were sort of grasping at straws,” Karp recalled. She tried an acupuncture-like technique called dry needling. Sometimes performed by a physical therapist or naturopathic physician, the treatment involves inserting small needles into muscles to relieve pain. That failed, too.

By August, Karp decided she was done searching for an explanation. “I had had extensive bloodwork and lots of tests” and was reassured that nothing serious was wrong, she said.

But in October, her mother, visiting from Florida, noticed Karp grimacing as she got up from the sofa. “She couldn’t believe I was still in pain,” Karp said. At her mother’s urging, she saw a third orthopedist. He gave her topical anti-inflammatory cream and suggested cortisone shots might help.

On the day her first shot was scheduled, Karp was unable to obtain it because of a paperwork glitch. The receptionistsuggested that Karp see an in-house physical therapist instead. The therapist asked Karp a question: Are you a dancer?

A diagnosis at last

When Karp replied that she had studied ballet for years and still loved dancing, she said the therapist’s response was unequivocal: “I know exactly what’s wrong with you — and our doctors can’t help you.”

“She used a lot of terms I didn’t understand at the time,” Karp recalled. She told Karp she was probably suffering from a form of hip impingement — the failure of the ball-and-socket hip joint to move smoothly. Impingement occurs in adolescence in part from repeated stress common in ballet. The head of the femur becomes abnormally shaped and no longer fits seamlessly in the acetabulum, or socket, putting the hip at risk of future injury.

The physical therapist advised Karp to see yet another orthopedist: Andrew Wolff, who specializes in arthroscopic hip surgery, in which miniature instruments reach damaged areas through small incisions. It is more often performed on shoulders and knees. Relatively few surgeons specialize in hips, a technically demanding procedure.

“I was cautiously optimistic,” Karp recalled.

At her initial appointment in early December, Wolff did something none of the other orthopedists had done: He ordered an X-ray of Karp’s hips.

“The X-ray really did show the whole picture,” recalled Wolff, adding that he was puzzled at the failure of other doctors to order something so basic. “Hers was not subtle.”

The physical therapist’s assessment turned out to be correct. The X-ray clearly showed that Karp had a disorder called cam-type femoroacetabular impingement. “It was as though my bones were a square peg trying to fit into a round hole,” she said.

A subsequent MRI scan showed that the impingement had shredded the labrum, the band of protective cartilage on the outside of the hip that helps cushion and stabilize the hip socket. Labral tears in dancers, as well as in people who play hockey, football, soccer and other sports, are common. “If kids mix up their sports a little bit, it might help” prevent such injuries, Wolff said. “Early subspecialization [in a sport] has not been great for our kids.”

But not everyone with hip impingement develops pain or other problems. “Some people are totally fine forever,” he noted.

The extreme positions required in ballet are particularly hard on hip joints. Wolff, an official physician for the Washington Ballet, said that some of his patients have undergone procedures to treat suspected gynecologic problems that were actually orthopedic, because the pain can move to the pelvis or the back.

Because of the duration and impact of Karp’s symptoms and because her scans showed no sign of arthritis — which would require a hip replacement — Wolff proposed reconstructing both labra with tissue from a cadaver and smoothing the femoral head to ensure a proper fit.

Karp said that when Wolff told her what was wrong and that her problem was fixable, she felt a mixture of disbelief and excitement. “I remember calling my husband on the way out of the office,” she said.

After getting a second opinion, Karp scheduled surgery with Wolff, who performs the 2½ -hour outpatient procedure about 300 times annually.

She underwent surgery on her left hip in January; her right hip was fixed in early March. “She’s done fantastic,” Wolff said. “The most common thing we see is people trying to push themselves too hard and too quickly” after surgery.

Karp said that now that her pain is mostly gone, she must battle the temptation not to overdo it. It may take as long as a year before she is able to run or dance again. She’s trying to pace herself. “It’s a series of small victories every day,” she said.

Submit your solved medical mystery to sandra.boodman@washpost.com. No unsolved cases, please. Read previous mysteries at wapo.st/medicalmysteries.