Maria Sharapova’s victory over Sara Errani last weekend was remarkable for many reasons.

She won the 2012 French Open in her first final on the red clay of Roland Garros. In the process, she became only the 10th female player to complete a career Grand Slam. But the most remarkable feat might have been that she was competing at all.

Sharapova’s battles with shoulder problems have been well-chronicled. In 2008, not long after winning her third Grand Slam tournament in Australia, she developed shoulder pain. She underwent an MRI, and doctors diagnosed her with inflammation. By July, her pain became so severe that she pulled out of a tournament in Montreal. She flew to New York, where she was met at the airport by renowned surgeon Dr. David Altchek. There he reviewed a new MRI and saw two tears in her rotator cuff.

After initially trying to treat her shoulder injury with rehab, she decided to have surgery in October. Sharapova told reporters in Paris at the French Open that she feared she might never return to tennis.

“I had my doubts. I would always ask around who had such problems with their shoulder and who recovered from it, and who had surgery and who got back to the top. And I didn’t get many answers back, which was a little frightening, because you always want to look toward the positives.”

After a long recovery that included a painful bone bruise, she finally returned to singles in May 2009 after a 10-month absence. She struggled for most of the next two years as well.

“It took a lot of time, it took a lot of bad losses, it took a lot of bad days. It certainly didn’t come easy for me,” she said. “I went through so many tough days to get here. I never put my head down. I was grumpy and I had my tough days and I would yell at people and say, ‘You’re promising one thing, and it’s not happening.’ I certainly had my doubts, but I kept going, and I didn’t let anybody tell me otherwise.”

If Sharapova had surgery to repair a rotator cuff tear and not simply to smooth out a partial tear, then her return to the top of the sport is remarkable. Rotator cuff tears are largely problems of older individuals that develop over time and with overuse. The rotator cuff tendons help stabilize the ball in the socket while the larger muscles of the shoulder, chest, back, and arm generate tremendous force with motion. The tendons are usually inflamed or frayed, which can usually be treated without surgery. Full-thickness tears are often career-ending injuries.

A repair of a full-thickness tear involves the surgeon re-attaching the tendon to bone with stitches and anchors. The overall rehab process involves weeks of immobilization, months of work to regain motion and strength, and then functional overhead training.

In elite overhead athletes, there is no guarantee that they ever return. In 2006, Dr. James Andrews published the results of a study that showed that only one of the 12 professional baseball pitchers on whom he had performed a repair of a full-thickness rotator cuff tear actually returned to play at a high level.

Tennis is not exactly baseball pitching, but the forces generated by the shoulder are very similar. An elite player requires a shoulder strong enough to generate crushing serves and groundstrokes thousands of times a day against the world’s top players. If Sharapova did, in fact, require such a surgery, the odds of returning to the world No. 1 ranking, or even returning to play at all, would have been stacked against her.

Dr. David Geier is an orthopaedic surgeon and Director of MUSC Sports Medicine. For more information about tennis injuries and other sports medicine topics, go to his blog at drdavidgeier.com.