The World Series Game 5 starters both had Tommy John surgery, which can help pitchers return to form. But not always.

Phillies Game 5 starter Noah Syndergaard and his counterpart on the Houston Astros, flamethrower Justin Verlander, both underwent Tommy John surgery in 2020.

They’re among hundreds of major leaguers who’ve had the operation since surgeon Frank Jobe first performed it in 1974. The procedure is nicknamed for his first patient, Dodgers pitcher Tommy John, who recovered well enough to pitch 14 more seasons.

The surgery involves reconstructing the ulnar collateral ligament in the elbow, typically by attaching a tendon that is taken from elsewhere in the patient’s body. Many pitchers and other athletes return close to preinjury form, but a good recovery requires months of rehab.

Both Game 5 starters are considered success stories — especially Verlander, who at age 39 can still throw a baseball 99 miles an hour. Syndergaard, 30, threw his fastball at an average speed of 94.1 miles per hour this season — still impressive, but several miles an hour slower than his peak.

Other Phillies who have had Tommy John surgery include reliever Seranthony Dominguez, in 2020, and Zack Wheeler, who went under the knife in 2015 while with the New York Mets.

For the backstory on the surgery — including whether there’s any truth to the belief that it can make pitchers even faster — we spoke to two orthopedic surgeons at the Philadelphia Hand to Shoulder Center: A. Lee Osterman and Kenneth A. Kearns.

Typically, surgeons reconstruct the patient’s injured elbow ligament by using a tendon that is “harvested” from the forearm.

But up to 20% of people don’t have that type of tendon in their forearm, Kearns said.

In such cases, surgeons can use a tendon from the patient’s hamstring instead, or they can harvest one from a cadaver.

The surgery lasts no more than 90 minutes, Osterman said. Surgeons must take special care to protect the patient’s ulnar nerve — the funny-bone nerve — positioning it in the reconstructed elbow to avoid irritation, he said.

Throwing a baseball at high speed places tremendous strain on the arm, especially for those who do it 90 or 100 times a game, on more than 30 occasions each season.

The ulnar collateral ligament, located on the inside of the elbow, bears an especially high strain, as the pitcher cocks it sideways before snapping the arm forward, Kearns said.

“Imagine revving your car’s engine up to 9,000 RPMs,” Kearns said. “That’s kind of what you’re doing to that elbow.”

Some players need Tommy John surgery because they’ve suffered acute tears in the ligament. More often, the ligament has simply become stretched out, Osterman said.

“Your ligament is lined up with pieces of collagen, kind of like a rope,” he said. “That rope kind of gets frayed like an old clothesline over time.”

Signs of injury can include pain inside the elbow, along with a decline in pitching velocity and accuracy. In recent years, this type of damage is occurring more often in teenage pitchers, because they throw too much before building up the necessary strength, the surgeons said.

Recovery from the surgery requires months of physical therapy and rehab. Patients first work on regaining their range of motion, then work on building up strength.

If all goes well, a pitcher can safely compete in games within a year.

But often, pitchers do not return to full strength until two years after the surgery, Kearns said.

“It’s a long, drawn-out process,” he said.

Roughly 70% of pitchers make it close to preinjury form after Tommy John surgery.

On average, pitchers who return to action throw a tad slower than they did before injury, but this falloff is not significantly different from normal age-related decline, according to one Columbia University study.

Some athletes need a follow-up “revision” surgery after the initial procedure and are less likely to return to action after that.

It’s a common belief that Tommy John surgery allows pitchers to throw even faster.

“It’s a myth,” Kearns said.

Yes, the procedure can help them pitch faster than they did while injured. But not any faster than their “natural” preinjury peak speed, he said.

Verlander, for example, used to be able to throw a baseball more than 100 miles per hour.