Mike Napoli’s Aching Hips: What is Avascular Necrosis?

Mike Napoli’s strange offseason has cost him a lot of money. After appearing to agree on a three year, $39 million contract with the Boston Red Sox in early December, he and the team finally agreed on a one-year contract worth just $5 million guaranteed dollars with up to an additional $8 million in incentives. As Eno Sarris wrote when the deal was announced, the team and player were both caught by surprise when a routine physical revealed that Napoli has a degenerative hip condition called avascular necrosis, which is what scared the Sox away from the multiyear deal. So what is avascular necrosis?

The first thing you need to know: it’s what basically ended Bo Jackson’s career. As the A.D.A.M. Medical Encyclopedia at the National Institutes of Health explains: avascular necrosis is “bone death caused by poor blood supply to the area.” Moreover, “Nonsurgical treatment can often slow the progression of osteonecrosis, but most people will need surgery.”

Avascular necrosis is asymptomatic at first, which is why Napoli didn’t know he had it. But then it results in serious pain, limping, and a limited range of motion, which means that corrective surgery will almost certainly be necessary sooner or later.

It’s also known as “osteonecrosis,” “ischemic bone necrosis,” “AVN,” and “aseptic necrosis,” in case you’re Googling. Also, as the Boston Globe notes:

Among the listed causes of AVN are steroid use, trauma, hypertension, rheumatoid arthritis, and alcoholism, or it could be idiopathic, meaning no cause can be determined. Certainly Napoli has had his share of wear and tear, being a catcher.

Jackson is the most famous athlete to suffer from avascular necrosis, but there are many others, across many different sports. One is backup Chicago Blackhawks goalie Ray Emery, who received the diagnosis in early 2010, underwent hip surgery including bone grafts, and then returned a year later, in March of 2011.

Another is Floyd Landis. Lance Armstrong’s nemesis won the 2006 Tour de France and then had hip replacement surgery to correct his degenerative condition. He won the race while suffering, mounting his bike with his right leg first because he couldn’t do it with his left. But he also won it while doping, and his championship was taken away after a positive drug test.

As the New York Times described his hip before it was replaced: “Essentially, the ball of Landis’s hip has withered and collapsed, resulting in bone that his doctors liken to a chunk of rotten wood, a sunbaked desert and a half-melted scoop of ice cream.”

Steroids are one of the possible causes of necrosis, though we will never know if that’s what caused it in Landis’s case. Or, for that matter, Napoli’s. But people will wonder, and that almost certainly is what caused it for 1970s wrestler “Superstar” Billy Graham. “His body [back] then was a collection of muscles,” the Phoenix New Times reports, “the result of thousands of steroid injections 100 times greater than the recommended doses.” By 1986, he was suffering from burning hip pain, and his doctor told him he had avascular necrosis, as he writes in his autobiography: “‘It’s the steroids,’ he said. ‘They’ve eroded your joints.'”

But avascular necrosis is often the result of trauma to the body, like you might see in a high-contact position in a contact sport. That’s what happened to Bo Jackson. As Dave Kindred wrote in The Sporting News, Jackson landed awkwardly following a tackle, and “that trauma ruined the joint where Jackson’s femur enters the pelvis. Cartilage, tissue and blood vessels were destroyed. Now it was bone on bone in there. And there wasn’t enough blood flowing in to sustain the bone’s life.” Jackson suffered the injury, had hip replacement surgery in 1992, and attempted a baseball comeback in 1993, but after 160 indifferent games over two years, and the strike in 1994, he called it quits for good.

Another leg trauma-related case was John Montefusco, a reliever for the Giants and Yankees in the ’70s and ’80s. He got into an auto accident in 1984, pitched 7 innings and had hip surgery in 1985, and then retired after 12 1/3 innings in 1986.

Then again, there’s the example of Brett Favre. When the Falcons traded him to the Packers in 1992, Favre failed his first physical in Green Bay because he was diagnosed with avascular necrosis. Former Packer general manager Ron Wolf chose to ignore the team doctor’s recommendation against the trade, opting instead to listen to the advice of an orthopedist who said Favre would likely have no immediate problems. “To this day, it bothers me from time to time,” Favre told the Associated Press in 2005. “I don’t have as much flexibility in that socket, but you’re kind of rolling the dice.”

It’s hard to know quite how bad it will be for Napoli. His condition is asymptomatic, which is a good thing, because that means they caught it early. But it’s unclear when or whether he may need surgery. If he does need to undergo surgery, then he’ll be out for a year with uncertain future prospects. Of course, as Brett Favre’s example indicates, you just never know. But it’s no wonder the Red Sox wanted to hedge their bets.