Study Shows Shoulder Injuries Sideline MMA Fighters

No tap-outs necessary.

A recent study in the Journal of Clinical Medicine highlights the significant impact of shoulder injuries on mixed martial arts (MMA) fighters’ careers. The study, “Return to Sport After Shoulder Injuries in Mixed Martial Arts: Implications on Longevity and Performance,” found that shoulder damage is strongly linked to reduced winning percentages, decreased knockout power, and shortened careers.

Not surprising.

Researchers examined 27 professional fighters from the UFC, Bellator, and Strikeforce whose shoulder injuries were severe enough to force bout cancellations. Following the injury, fighters’ winning percentages dropped from an average of 82% pre-injury to just 55% post-injury. Knockdown rates also declined substantially.

“The shoulder is essential in both striking and grappling,” said Hafiz Kassam, M.D., director of Shoulder Reconstruction at Hoag Orthopedic Institute, study co-author, and former competitive boxer. “When the shoulder is compromised, a fighter’s ability to perform at an elite level can be severely hindered—not only physically, but in terms of long-term competitiveness.”

A torn labrum was the most common injury, representing over 40% of the cases. More than three-quarters of the fighters required surgery, and one in five continued to experience persistent shoulder issues even after recovery, the study data show. While strike accuracy remained relatively stable, knockdown power was significantly affected—suggesting that many fighters adapt their style post-injury to compensate for decreased shoulder strength.

The study calls for improved rehabilitation protocols and stricter return-to-sport guidelines to protect athlete safety and preserve career longevity.

The research was a multi-institutional effort, co-authored by specialists from Hoag Orthopedic Institute (Irvine, Calif.), Rothman Orthopaedic Institute (Philadelphia), Rutgers Robert Wood Johnson Medical School (New Brunswick, N.J.), Wayne State University School of Medicine (Detroit), Johns Hopkins University Department of Orthopaedic Surgery (Baltimore), and the Southern Permanente Medical Group (Pasadena, Calif.).

“This research offers a wake-up call to fighters, trainers, and medical staff,” Dr. Kassam added. “Better injury management could make a meaningful difference in not only extending fighters’ careers but also improving long-term outcomes.”

Hoag Orthopedic Institute (HOI) is the West Coast’s premier hospital and surgery center network dedicated to orthopedic and spine care. Collectively, HOI’s physicians perform the highest volume of hip, knee and shoulder replacement surgeries on the West Coast and the most spine surgeries in Orange County, California. Complementing its excellence in musculoskeletal patient care with academic research and education and fellowship programs, HOI trains the next generation of orthopedic surgeons under its roof and pioneers innovative treatment protocols. HOI was proudly founded by its founding physicians in 2010 in partnership with Hoag.