In a sports medicine office in Towson after school one day recently, two newer members of the sorority "ACL" exchange pleasantries.
"Oh, your bruise looks better already," Kelli Kramer, 17, a Dulaney High volleyball and basketball player, tells a fit-looking, dark-haired girl walking gingerly toward a therapist's table. Kramer, a senior, smiles, her face flushed from a strenuous set of "lunges," a thigh-toughening exercise.
"Uh thanks," responds Nicole Froman, 18, The Sun's co-Player of the Year in girls soccer last fall. Her wan return smile acknowledges the empathy only an ACL sister could offer about the fading black, blue and yellow streak that extends from her left thigh, through freshly healed stitch scars, down into her calf. Froman, a Loch Raven High senior just 1 1/2 weeks off an operating table, is newer to this ordeal than Kramer.
It's some sorority, this ACL -- shorthand for part of the knee called the anterior cruciate ligament. Initiation requires surgery, produces scars and five-figure expense but in most cases the ability to play again.
Sorority membership is booming, too, particularly among high-school-age athletes -- up easily by many thousands nationally in the past decade, although because no records are kept centrally, no one knows the exact number.
Yet as Dr. Garrett J. Lynch, an Annapolis sports medicine surgeon who specializes in knee reconstructions, says, girls such as Kramer and Froman are part of "a high school phenomenon -- an epidemic of serious knee injuries among young, female athletes."
They and their sisters nationwide constitute a bedeviling facet of females in athletics today:
Depending on the sport and which university research you're reading, female athletes are from two to eight times more likely than males playing the same sport to incur an ACL injury. The number heard most often is "four times more likely." Whatever the real figure, that's a ratio wrapped in vexation.
For starters, the problem appears more severe in high schools. But it's still best detailed at the college level, where injury data are easier to obtain and most researchers are employed.
Published research relates mainly to widely played sports, soccer and basketball. Locally, though, coaches and doctors quickly add lacrosse, and some cite volleyball.
The subject of female ACL injuries seems to have surfaced in medical literature 22 years ago. But the most comprehensive studies have been published only within the past few years.
A 1996 monograph on the subject from the American Academy of Orthopedic Surgeons observed that "as recently as the 1970s women were 'too dainty' to tear their anterior cruciate ligaments."
Virtually all research on the subject has been done on college athletes. Yet Lynch and many others say the sheer number of injured girls is considerably larger on high school and club teams for no other reason than vastly more girls compete on them.
Anecdotal evidence about ACL injuries abounds. Ask any orthopedist, trainer, player or referee.
Did you hear about the two girls at Fallston this year? How about the two at Perry Hall last year? Two at the new Long Reach in Columbia? One soccer player with both knees in two years at Liberty but she played again last fall? Another with the same knee twice in successive years at Loch Raven, now at College Park? Plus girls at Overlea, Parkville, Oakland Mills, Glen Burnie and Severna Park and in the city, at Northwestern? And on and on.
Dr. John B. O'Donnell, an orthopedic surgeon long involved in sports medicine at Baltimore's Union Memorial Hospital, is one who says the proportion of female injuries to male is "similar in high school to those in college."
But as he says, "Whether it's four or seven times more, it's a lot."
No one is sure why females experience knee injuries so much more frequently than males.
Research concentrates heavily -- but inconclusively -- on physiology. Many say the "femoral intercondylar notch," where bones meet in the knee, is more narrowly shaped in females than in males, pinching the ACL when the knee undergoes sudden, extreme stress. Some believe the female pelvis, which to accommodate childbirth is wider than a male's, distributes abrupt pressure to the knee at an angle that boosts the odds of ACL damage.
Others think the female knee hyper-extends more easily than the male knee. Still other researchers probe conditioning, how female muscles function, hormones and how young girls learn to run and jump compared with boys.
Dr. Leigh Ann Curl, an orthopedic surgeon, assistant director of the Johns Hopkins sports medicine department and former University of Connecticut basketball player, says it is only logical that a combination of factors is in play.
"It's almost like studying the Chesapeake Bay crab population," she says. "There are so many variables, it's confusing."