The bad news is Penguins star Sidney Crosby will be out of action for six weeks due to a high-ankle sprain.

The good news? The injured ankle likely will be stronger once it heals, with less likelihood of re-injury in the future.

OK, that's a stretch to find a silver lining in the Penguins' cloud. But the high-ankle sprain is a serious injury that involves the tearing of ligaments that hold two leg bones together.

Only time and rehabilitation will correct it.

That's the opinion of Dr. Tanya Hagen, a University of Pittsburgh Medical Center sports medicine physician, who is not involved with the Penguins or Mr. Crosby's treatment.

But as sports physician for the Robert Morris University hockey team, she's seen many high-ankle sprains in her practice on the South Side.

Lateral ankle sprains to the side of the foot are more common injuries. But the high-ankle sprain can be more serious because it involves the tearing of ligaments holding together the fibula and tibia -- the two leg bones that run from the knee to the ankle.

"The jury is out on what the proper treatment is," Dr. Hagen said. "There are 10 ways to skin that cat and no studies on the best way to treat a high-ankle sprain."

Depending on its severity, treatment can range from immediate therapy to immobilization of the leg with a cast. In the worst-case scenario, the ligaments are torn apart, requiring surgery to bolt the bones back together, she said.

A six-week layoff, as projected for Mr. Crosby, indicates a moderate sprain that likely does not involve a complete tear. But that's only an educated guess.

"Six weeks is not unreasonable for a moderate high-ankle sprain," Dr. Hagen said. "It tends to be worse than the traditional sprain because stress makes it worse. So you have to treat it more conservatively up front."

Here's precisely what happens when a high-ankle sprain occurs, according to Dr. Hagen:

By definition, a sprain means that a ligament -- the fibrous material that connects two or more bones -- has been torn.

In the high-ankle sprain, two ligaments connect the smaller fibula bone to the larger tibia bone at the ankle -- the anterior, or front ligament, and the posterior, or back ligament.

The joint that the tibia and fibula form sits upon the talus bone of the ankle like a saddle on a horse. A third fibrous tissue connecting the two bones is a sheath known as interosseous ligament, which further strengthens the connection of the two bones.

That connection of bones is designed only to have limited motion. But when the foot is wrenched outward, or into a duck-like position, while the leg is fixed in place, the connection is put out of place and pried apart by the talus bone below, causing ligaments to tear.

The result is one big ouch and many weeks off.

Actually, high-ankle sprains are more common in football, where bodies often fall on ankles. But Dr. Hagen said she also sees it in hockey players, despite the support provided by the skate and the reduced resistance from the ice. There's also controversy about whether artificial turf causes more high-ankle sprains.

The high-ankle sprain has become part of the sports lexicon in recent years because physicians are more knowledgeable about them. People also seek treatment more often from sports physicians who have long been familiar with the injury.

Unlike other sprains, when the high-ankle sprain heals, Dr. Hagen said, calcification of the ligaments strengthens them, making a recurrence less likely. On the downside, such an injury also can lead to tendonitis and arthritis, especially if the injury also involved bone bruising and cartilage damage.

"If you don't allow it to heal properly with appropriate rehabilitation, the athlete is at risk for more injury to the ankle and could also be predisposed to other injuries to the knee and hip," Dr. Hagen said.

So her ultimate advice applies to one's luck as well as one's ligaments: When it comes to repairing high-ankle sprains, neither should be stretched too far.