University of South Carolina starting catcher Grayson Greiner will miss this weekend’s NCAA regional in Columbia after undergoing surgery Thursday morning for a torn meniscus. Coach Ray Tanner told reporters that the freshman suffered a torn lateral meniscus in his left knee during practice Wednesday.

“He was taking batting practice. It was an inside pitch. I was actually throwing. He kind of took a swing, maybe a check swing. His hips rotated and apparently his cleat got stuck. ... That was the only thing we could come up with, that his hips rotated but his foot didn’t, so it caused pressure on the knee and caused the tear,” Tanner explained.

University of South Carolina Sports Medicine orthopaedic surgeon Dr. Christopher Mazoué likely performed Greiner’s knee surgery. Tanner said that he was called shortly after the procedure. “It was a lateral meniscus tear — bucket-handle variety. He did well. He should respond quickly. If we’re fortunate enough to advance, he will probably be activated next weekend. Will he be able to catch? Unlikely. But his prognosis is “rehab tomorrow and you can go as you can tolerate the pain.”

Greiner tore the lateral meniscus of his left knee. To understand his injury, place your left thumb and index finger in the shape of the letter C. That is the lateral meniscus, sitting between the femur (thigh bone) and tibia (shin bone) on the outside of the knee. Now imagine a tear within that meniscus that extends all the way around but is attached in the very front and back (tips of your fingers). The inner torn part of the meniscus can flip back and forth within the knee, like the handle of a bucket.

Fans might wonder why the All-SEC Freshman catcher would need surgery immediately instead of playing through it until the end of the season. Meniscus tears usually don’t heal on their own, making surgery inevitable at some point. They typically occur with twisting maneuvers, such as swinging the bat. Any twisting motion would likely be very painful. Also, any deep knee flexion, such as squatting, would aggravate the tear. Catchers put their knees in that position hundreds of times a game.

There are two surgical treatments for meniscus tears. Due to the location and pattern of most tears, the vast majority are trimmed out — what sports medicine surgeons call a partial meniscectomy. The surgeon looks in the knee with a scope and uses scissors and a shaver to remove the inner part catching between the bones, leaving the rim to remain as a shock absorber.

Recovery from a partial meniscectomy can be relatively quick. The surgeon usually allows full weight bearing. The athlete works to increase range of motion and strength of the knee while decreasing swelling. High-level athletes often return to sports in as little as two to four weeks, although they continue to improve for months. Certain functional movements, especially twisting and squatting, can be performed, although they are often difficult early.

The other treatment for meniscus tears is a repair, meaning that the surgeon sews the tear back together with stitches. A repair potentially saves the entire meniscus to serve as a shock absorber later in life, so it is ideal when possible. Unfortunately surgeons often find it necessary to protect the repair, by limiting weight on the leg and range of motion of the knee, in order to optimize the chance of healing. Recovery and return to sports take much longer, usually three to four months.

As of late Thursday afternoon, there was no official word on whether Greiner underwent a partial meniscectomy or meniscal repair. Tanner’s statement that his catcher could be activated next weekend suggests the surgeon trimmed part of the meniscus out. But his mentioning specifically that the tear was “the bucket-handle variety” suggests that the longer rehab period could be in play. A bucket-handle meniscus tear, by definition, is one of the types of tears that is, in fact, repairable.

Gamecocks fans might be surprised that a seemingly innocent swing of the bat could cause such a serious injury. Now those fans wait cautiously to see if Greiner’s knee heals enough to allow him to join his teammates on their quest for a third-straight national championship.

For more information about meniscus injuries and other sports medicine topics, please go to Dr. Geier’s blog at drdavidgeier.com.