The procedure itself was nothing out of the ordinary for a seasoned orthopaedic surgeon like C. Lowry Barnes, M.D., but the response he received from the patient will always be a special memory for him.

In the middle of a medical mission trip to Trinidad, Barnes had just helped a middle-aged woman move her hip to show her the arthritis pain she had suffered from for years was gone. Overcome with joy, she expressed her thankfulness by kissing Barnes’ hands.

“It gets you pretty fired up,” said Barnes, who grew up in Pine Bluff.

It’s always satisfying to travel to faraway lands with experienced colleagues to provide medical care to those less fortunate. It’s the exact reason Barnes has gone on so many trips with Operation Walk in the last decade.

Barnes is now one of the region’s foremost joint replacement experts and professor and chair of the Department of Orthopaedic Surgery in the College of Medicine at the University of Arkansas for Medical Sciences.

He and his physician assistant, Sara E. Foster, were two of the more than 50 health care professionals — including nurses, anesthesiologists, hip and knee surgeons and other operating room staff — who collectively replaced 52 joints in 48 patients in Trinidad over the week of Oct. 13.

The trip was sponsored by Operation Walk Maryland, a not-for-profit group based in Baltimore and one of the many chapters of Operation Walk USA that offers free surgical treatment for patients in developing countries and the United States through volunteer medical service.

Barnes met Lawrence D. Dorr, M.D., founder of Operation Walk USA and The Dorr Arthritis Institute, and Paul Khanuja, M.D., leader of Operation Walk Maryland, during his John Insall Traveling Fellowship in 2006. Since then, Barnes has accompanied Dorr and Khanuja on several mission trips to Peru, India and Trinidad. He joined Operation Walk Boston to the Dominican Republic, where he worked with his peers from a previous fellowship at Harvard Medical School.

The group spent the first day evaluating patients and performing the first four surgeries. The next days started around 7 a.m. and lasted until about 7 p.m. In between, doctors, nurses and other staff inhabited four operating rooms as patient after patient was wheeled in for surgery.

One of the noticeable things on a trip like this, Barnes said, is the increased severity of conditions in patients, compared to stateside because of the lack of widespread care and treatment.

“Many of the patients are much worse off because they’ve been without care for so long,” said Barnes. “Here, we manage orthopaedic conditions and if treatment fails, there are many surgeons to address the issue, but that’s not the case in many parts of the world.”

Gratitude from the patients is one of the main reasons Barnes continues to go back.

“It’s always a very rewarding experience that allows you to work with other wonderful surgeons from around the country in a less fortunate place,” said Barnes. “Obviously, it does so much for the patients, but the surgeons benefit just as much because we’re reminded of why we became surgeons: To take care of others.”

This particular trip had extra meaning for Barnes because his daughter, Sally, currently a sophomore in college, came along to assist.

“Sally has a heart of gold and really enjoys these types of mission trips,” said Barnes. “It was special to be able to see her excel and do such a great job.”

Trips like this will continue to be a part of Barnes’ efforts. He’s already planning his next trip with Operation Walk in the spring. This time, in Nicaragua.