This injury occurs in young people, often for the same reasons as muscle tears. Overstretching orovercontracting, sudden, unexpected demands on the muscles, cold muscles being forced to work too hard—all these things that would most likely do no more than injure a muscle in an adult can do something quitedifferent in a growing person. They can pull the muscle away from its tether, popping off a piece of bone inthe process. Bouncing into the splits can do it— thus the name cheerleader’s hip. This injury can pop thehamstrings or the adductors (the muscles in the upper, inner thigh) away from the pelvis. If the quadricepscontracts violently, the portion of the muscle that connects to the pelvis, the rectus femoris, can pull a pieceof bone away.
Why will the same incident pop off a piece of bone in a young person and only tear a muscle in anadult? Because in young people bone is still forming. It’s geared to grow and heal. Accordingly, it’s coveredwith a dense, blood-rich tissue called periosteum. Adults’ bones are covered with periosteum as well, butwhereas in a grown person the periosteum is usually paper-thin, in a child it can be as thick as one sixteenthof an inch. In kids the muscles and tendons, where tears occur in an adult, are stronger than their interface with the bone. So if anything is going to pull loose in a child, it will be bone. That’s just what happens incheerleader’s hip.
So all of a sudden a piece of periosteum and bone as big as your thumb finds itself no longerconnected to the pelvis but floating somewhere in the muscle-tendon area. “What am I doing here?” it asksitself. “I should be doing something.” What it does is the only thing it knows how to do: it makes more bone.So into the doctor’s office comes a teenager with a lump of bone the size of half a baseball in the buttocksfrom, say, a hamstring tear. The unhappy kid is very uncomfortable, only sits on the uninjured buttock, andhurts whenever she moves. And besides the discomfort caused by the lump of bone itself, a bursa thatformed over this bone to provide a cushion has become irritated and is swollen to the point where the poorteenager feels as though there are two baseballs in there.
+ What to do about it + See a doctor. But make sure that the doctor is used to treating athletes, and youngones at that. In an x-ray these bone growths can look just like malignant bone tumors, and it’s not uncommonto hear of people being operated on and biopsied because the physician feared the worst. As a doctor, if youdon’t know that these sorts of injuries can happen to kids in athletics, especially teenagers in the middle ofgrowth spurts, and you don’t ask a lot of questions to find out exactly what happened, the x-rays can scareyou to death. Here’s one situation in which experience can make a big difference.
Sometimes surgery is required. The wayward piece of bone can be screwed or stitched back to thepelvis. Sometimes the piece of bone will build up and then taper back down by itself, and by taking it easy youcan wait it out. But the important thing is to know what the problem is; then you can act accordingly. See adoctor.