“He’s screwed.”

Those words summed up the reaction of Indianapolis Colts offensive lineman Gordon Cherilus to news that Houston Texans linebacker and former University of South Carolina star Jadeveon Clowney had undergone microfracture surgery.Microfracture

Cherilus has had microfracture surgery in his knee, so he understands the challenges Clowney faces after that surgery and the long rehab that goes with it. A look at the surgery and its long-term results paint equally grim picture.

The knee injury of Jadeveon Clowney

The number one pick in this year’s NFL draft battled injuries before the season ever started. He underwent surgery to repair a sports hernia in June. He missed time after suffering a concussion in a preseason practice. Then Clowney injured his right knee in the first regular-season game against Washington.

The Houston Texans announced that Clowney had torn his lateral meniscus, and he quickly underwent arthroscopic surgery to trim out the torn part of the meniscus. He missed six games before returning to play in Week 8 against Tennessee. But pain and swelling returned, so the team rested him for two more weeks. Clowney visited Dr. James Andrews for a second opinion, and microfracture surgery was performed early last week.

Cleaning up articular cartilage damage

According to the Houston Chronicle, the Texans knew at the time of his September 8 surgery that a second, more invasive surgery might be necessary. Texans general manager Rick Smith told the newspaper, “The original injury he suffered on opening day wasn’t just limited to the lateral meniscus. He also had some cartilage damage, as well.”

Smith noted that the surgery aimed to clean up the meniscus and cartilage with the hopes that would be enough to allow him to play. We now know a cleanup was not enough.

Treatment of articular cartilage defects

The articular cartilage is the cartilage lining on the ends of the bones. If an athlete has an area of damaged cartilage, the exposed bone and roughened joint surface can cause pain, popping and swelling with activity. “Cleaning up” the roughened edges of articular cartilage can decrease symptoms, but it does not fill in the missing cartilage.

Normal articular cartilage of the knee
Note the smooth appearance of healthy articular cartilage (red arrow).

Microfracture and its success rates

Microfracture is an arthroscopic procedure in which the surgeon uses what looks like a fancy ice pick to make small holes in the bone several millimeters apart. Blood then flows from these holes into the defect. The blood and other growth factors create an inflammatory process that leads to the formation of fibrocartilage. This fibrocartilage is rougher and more brittle than the normal type of cartilage that lines the bones, but it’s better than exposed bone.

For small cartilage defects, microfracture is thought to have reasonable short-term success. Dr. Richard Steadman, who pioneered the surgery, found that 76% of the NFL players in whom he performed microfracture returned to play the following season.

The long-term results after microfracture surgery are more concerning. A study of 24 NBA players who underwent the procedure showed that only 58.3% returned to play for more than one season after the surgery. Performance suffered greatly after players returned, with average points, rebounds, assists and minutes played dropping after microfracture. And one third of the players never returned play at all.

The challenge of restoring normal articular cartilage

The problem with these poor results lies less with the surgery than with the underlying injury. Orthopaedic surgeons have no way to regrow or make articular cartilage new again. Microfracture creates fibrocartilage, which might be adequate for athletes returning to play in the short-term, but it could shorten their careers and lead to long-term arthritis.Football helmet

Other surgeries, like transferring cylinders of bone and cartilage from other parts of the knee or culturing cartilage cells in the lab and re-implanting them into the defect are much more invasive surgeries that would be extremely difficult for returning to professional sports.

Return to play after microfracture

Despite these numbers, it’s still entirely possible that Jadeveon Clowney goes on to have a successful career. Hall of Fame defensive end Bruce Smith reportedly played six seasons after undergoing microfracture surgery.

It’s just as likely, though, that Clowney’s career follows the trajectory of former NBA number one draft pick Greg Oden. Oden underwent microfracture surgery shortly after the draft and ultimately had an injury-plagued career in which he never made a significant impact.

Also read:
Greg Oden to miss season for microfracture surgery (again!)
Will Bowers’ knee scare off NFL teams?

Texans head coach Bill O’Brien rejects the notion that Clowney is a bust or that he is injury prone. “I do want to say this guy has worked extremely hard to recover from injures,” O’Brien shared. “I want to be real clear about this as it relates to the Texans. We think very highly of him. We know he’s going to be a really good player. He’s been unlucky.”

Unlucky might be an understatement.

Note: This post appears in a modified form as my sports medicine column in the December 16, 2014 issue of The Post and Courier.