When it comes to repairing pulled abdominal muscles or aching abductors, William Meyers is the go-to guy.

The 65-year-old surgeon is the founder of the Vincera Institute at Philadelphia's Navy Yard, where marquee athletic stars and weekend warriors travel from across the country to fix core and hip injuries. The rehabbed USO building houses services from diagnosis to imaging to rehabilitation.

Since the 1980s, Meyers has performed some 20,000 operations on core muscles for the famous and the not so famous, about 700 over the last year alone.

Meyers' patient list is a who's who of past and present Philadelphia sports stars - including former Eagles quarterback Donovan McNabb, Eagles tight end Brent Celek, and Phillies pitcher Cliff Lee. Not to mention such other greats as retired NBA star Grant Hill, former Green Bay Packers wide receiver Greg Jennings, and Detroit Tigers pitcher Justin Verlander.

Core injuries occur when there is a severe strain or pull of the abdominal wall muscles in the region where they attach to the pubis bone. Injuries to the core area - also known as athletic pubalgia or "sports hernia" (although in the vast majority of cases, there is no hernia involved) - can arise from wear and tear. But others are acute injuries, such as those among rodeo riders, who may suffer damage from hyperextension.

"The core is your transmission," said Meyers. "Core muscles harness all the power muscles. If you think of any movement in sport or any activity, from dancing to working out in a fitness center, your extremities are dependent on this transmission."

"If you injure something in the core, it creates an imbalance and lack of power," he said.

Recent research at Vincera shows core injuries could also make athletes more prone to concussions. "People who have core injuries actually have decreased reaction and a loss of visual field," Meyers said. "Correct the core and you correct those problems."

As a doctor working in sports medicine during the 1980s at Duke University, Meyers believed the core's functional anatomy wasn't taught well.

"All we did was memorize muscles," he said in a recent interview.

More and more, he suspected repairs to so-called sports hernias often didn't solve core and hip problems. He took his suspicions to the cadaver lab and had a medical student put her finger behind some thigh muscles while he cut an abdominal muscle.

"She let out a scream as the pelvis tilted forward and pinched her finger," he said. That was Meyers' eureka moment, vividly capturing how the abdomen connects to the thighs.

Over the years, Meyers developed his surgical approach for the treatment of core muscle injuries, working on a combination of reattaching abdominal muscles and repairing or releasing the abductor muscles of the hip. He tailored operations to fix a variety of groin injuries, rather than treating them all alike.

At Vincera, surgeons work in teams so patients can receive both core surgery and hip arthroscopy during the same procedure if needed. That avoids two separate rounds of anesthesia, Meyers said, promoting faster recovery.

The team approach extends to Vincera's "whole body" approach to rehabilitation - whether or not a patient requires surgery. At an on-site yoga studio, Meyers has developed a series of 20 protocols of poses and breathing exercises that track patients' recovery. At the start, for example, a patient might be able to hold a pose on the barre but by the end of the series may progress to holding the pose on the floor, without the barre's support. Nutrition is also stressed, with a chef designing all-natural menus to decrease inflammatory foods and increase anti-inflammatory choices, which can help promote pain recovery.

The institute also promotes a massage program, with therapies that break up scar tissue from surgery to promote faster healing and greater muscle flexibility. Image-guided injections of cortisone and even stem cells are also available to help with pain management.

Major sports teams, universities and workmen's compensation organizations recognize core injuries and pay for repairs, but for other patients, costs can reach $13,000 out of pocket. That's because private insurance and Medicare don't cover Meyers' core operations. For instance, Independence Blue Cross, while praising Meyers as a "well-respected surgeon with strong academic credentials,'' considers the procedure experimental since it has not been subjected to randomized clinical trials, in which some participants get the treatment and others do not.

The insurance company is wrong in suggesting the need for a randomized controlled study,'' said Meyers, whose own reviews show up to a 96 percent success rate. "It is simply not ethical to ask any such injured patient, let alone a sports star, to consent to a 50 percent chance of not fixing the problem," he said.

In the case of core injuries, in which most patients have been through rehabilitation and have not gotten better and then are sent to Vincera for surgery, a randomized controlled study would be difficult, if not impossible, says Brian Sennett, chief of sports medicine at Penn Medicine.

"While I think it would be great to prove to patients, hospitals, health-care providers and insurers that the operations work, it doesn't seem realistic to take half the patients randomized in a nonoperative segment when they already failed nonoperative treatment," he said.

Alan Zuckerman, president of Health Strategies & Solutions, a Philadelphia health-care strategy firm, said he was not surprised that patients will pay cash for what Vincera offers.

"You probably would be blown away by all the athletes and weekend warriors who think that they are still athletes and who will pay for procedures in the hope of restoring them to their past performance," he said.

For 18-time Philadelphia marathoner Leo Miller, 45, who had such severe abdominal pain that he gave up running for a year, the $10,000 out-of-pocket costs have been worth it.

After a futile search with other local doctors to find a cure for his injury, Miller was referred to Vincera, where he was diagnosed with core problems and underwent surgery followed by rehabilitation.

A month after his operation, he was back to running, and, now, 12 weeks out, he's clocking five miles a day, with plans to attempt a marathon in the fall.

"What was the cost of not having the operation?" Miller asks as he performs squats at the Vincera gym.

"I thought I might never run again," he said. "I believe I bought myself years of activity."