WHB and the NYTimes are like ONE these days.

[11-year-old] Collin had an injury that doctors used to think almost never occurred in children. He had torn the anterior cruciate ligament, or A.C.L., in his left knee, the main ligament that stabilizes the joint.

Although there are no complete or official numbers, orthopedists at leading medical centers estimate that several thousand children and young adolescents are getting A.C.L. tears each year, with the number being diagnosed soaring recently. Some centers that used to see only a few such cases a year are now seeing several each week.