Cyclist Lance Armstrong wrote that he will choose to undergo surgery shortly after a crash in a race Monday left him with a broken collarbone and uncertain stakes in the 2009 Tour de France.
Armstrong fell off his bike in a pile-up in the final 12 miles of the 109-mile first stage in the Vuelta a Castilla y Leon race in Spain. The injury took the seven-time Tour de France champion out of the Spanish race and landed him back home in the United States to await treatment, according to Phillippe Maertens, a spokesman for Armstrong's Team Astana.
"I'm alive! Broken clavicle (right). Hurts like hell for now," Armstrong, who was competing in just his third stage race and fourth competition overall since coming out of retirement this year, tweeted on the social networking site, Twitter. "Surgery in a couple of days. Thanks for all the well wishes."
Sports medicine experts say that although collarbone fractures are extremely painful, they often heal on their own. In fact, it's sometimes possible for cyclists to train indoors during healing and in some cases undergo surgery to speed up their recovery.
"Sometimes athletes -- and this happens in Europe among soccer players -- they're actually treated surgically to get them back on the field more quickly," said Dr. Frank A. Cordasco, an orthopedic surgeon at the Hospital for Special Surgery in New York City.
If the break is simple, Cordasco said it's possible for doctors to insert a titanium rod to stabilize the bone and speed up the healing process.
"You put a small flexible rod through the middle of the bone and it fixes the fracture and enables the fracture to heal," he said.
But if the collarbone broke in multiple places, Cordasco said Armstrong might have to undergo a more complicated procedure with a series of metal plates and screws.
Cordasco said a person's pain tolerance can also sometimes determine time off from competition.
Cyclist Tyler Hamilton sustained a clavicle fracture during the 2003 Tour de France, and was actually able to finish in fourth place.
Although Armstrong's personal Web site said he is "officially retired," the 37-year-old cancer survivor and seven-time Tour de France champion had returned to racing with the Astana team and was said to be preparing for a run at an eighth Tour de France title.
Despite the injury Monday, Maertens said Armstrong could be back on the road in a month, in time for a race in Italy in May and the Tour de France in July.
"The collarbone is broken, and I have a little bit of road-rash abrasions," Armstrong said as he left Valladolid University Hospital. "I've never had this happen before; it's pretty painful. I feel really miserable."
Armstrong had already covered 97 miles of the stage and was at the front of the pack when he fell, Maertens said, adding that Armstrong knew immediately what had happened, although he had never before broken his collarbone in his 17 years as a cycling professional.
When he fell, Armstrong's first reaction to the crash was reportedly to utter the single word "sh**."
From the time he returned to racing in 1998 after his battle with testicular cancer to his retirement after the 2005 Tour de France, Armstrong was not sidelined for any significant time periods from crash-related injuries in training or competition, although he did take an occasional spill.
"Crashes are a part of what we do in training and in racing," he told Sports Illustrated in 2000. "It seems like every year, I have two big crashes. I did last year, I did this year. Like I said, it is just part of our job."
While training for the 2006 New York City Marathon Armstrong experienced some of the most taxing injuries of his athletic career.
"I'm icing my shins right now," Armstrong told USA Today in November 2006. "I've been riding the bike lately because of these nagging little injuries."
That shin splint problem was diagnosed as a stress fracture 10 days after the marathon, according to Armstrong's Web site.
Zooming down roads at speeds averaging more than 25 miles per hour, professional cyclists risk serious injury even from a simple fall, according to Dr. Sherwin Ho, an associate professor of surgery and the director of the sports medicine fellowship at the University of Chicago.
"Any fall directly onto the shoulder basically collapses your shoulder in against your body," said Sherwin.
Under normal circumstances, two body parts work in tandem to keep the shoulder in place -- the clavicle bone that keeps the shoulder joint at the right distance from the body and a ligament called the AC (acromioclavicular) joint that connects the shoulder to the clavicle.
In a fall, "something has to give, and it's either one of these two," said Sherwin. "It seems like the higher the impact, the faster they break, the more often well see the collarbone break." Sherwin said he sees more AC tears from people falling at lower speeds.
Sherwin said it is sometimes possible to tell whether someone fractured a collarbone or tore an AC joint just by looking at the person. For instance, a clavicle bone jutting out under the skin by the shoulder often indicates an AC tear.
"If you see it, that's actually the end of the clavicle sticking out," said Sherwin. On the other hand, a fractured clavicle often looks like general bruising and swelling on the center of the bone.
In either case, Sherwin said a fractured clavicle or torn AC ligament are relatively easy to treat. "It's just a lot of pain, and it's hard to use your arm," said Sherwin. "In most cases you don't need to fix it, you just need to protect it and leave it alone."
Unless Armstrong completely snapped his clavicle in half and has a gap between the pieces, Sherwin predicted he may not need surgery. However, it is likely that Armstrong will need several weeks -- Sherwin often recommends six at minimum -- before he can go back on the road.
But Jacinto Vidarte, the press director for the Vuelta of Castilla, said he has seen athletes return from similar injuries much sooner -- around four weeks, or even earlier.
"If you start too early you run the risk of re-injuring it," said Sherwin. "You need that arm to control the bike or you'll end up crashing again. So it's key that he heal before he starts riding."
Most cyclists can continue training on a stationary bike while their shoulders heal.
Unlike many other contact sports, Sherwin said cyclists face only the occasional acute injury.
"The incidence of injury is not as high as a contact sport," he said. "However, when you do get a traumatic injury because they're moving at a high rate of speed, and because they're falling from a high position on the bike, and because they're falling on a concrete, then the injuries tend to be more severe."
ABC News' Miguel Marquez contributed to this report.