Stress Fractures -- Who Gets Them and Why?
July 18, 2001 -- Weekend warrior or serious competitor, we can
all fall victim to stress fractures, small but painful bone weaknesses caused
by repetitive stress. Such fractures are responsible for an estimated 10% of
all sports overuse injuries.
William O. Roberts, MD, a family physician at MinnHealth, in
Minnesota, and vice president at the American College of Sports Medicine,
likens a stress fracture to bending a paperclip back and forth: "Eventually
you get little cracks."
While stress fractures are pretty common in the lower
extremities -- the shin, foot, ankle -- they can also occur in the back or in
the arms, says Nicholas A. DiNubile, MD, an orthopaedic consultant to the
Philadelphia '76ers and the Pennsylvania Ballet.
Both Roberts and DiNubile say overtraining is the main reason
people develop stress fractures. But beyond that, "any sudden change in the
intensity, duration, or frequency of training program" can also place an
athlete at risk, says DiNubile.
In most cases, treating a stress fracture can be summed up in
one word: rest.
"Treatment usually is to stop the offending activity,"
says DiNubile, adding that more severe stress fractures may need to be treated
with a cast, or in rare instances, with an operation.
But resting doesn't mean giving up all training. Both Roberts
and DiNubile say athletes can continue to work out. "Keep conditioning up
by low impact alternatives," says DiNubile, like swimming or cycling.
"Also you need to deal with any biomechanical factor,"
says DiNubile, referring to individual physical traits that could interfere
with motion. "For example, get a lift if your legs are uneven, or custom
orthotic insoles if your arch is problematic," he says. "And make sure
that your training program is a gradual one. We use the 10% rule: Don't
increase a training program more than 10% each week. That allows your body to
adjust and accommodate and react to the new stresses."
Roberts adds good nutrition and calcium supplementation to the
list of treatments, along with estrogen supplementation for women with low
estrogen. "And there are some newer treatment modalities that are coming
down the pike, such as ultrasound or magnetic field stimulation of the
site," he says.
While stress fractures are common, recurrent fractures are less
so. To find out why some athletes are more susceptible than others to repeated
fractures, a Finnish research team recently completed a comparative study of
the anatomies, nutritional history, training programs, bone mineral densities,
and hormonal histories of 31 athletes with multiple stress fractures and 15
athletes without fractures.
Among male athletes with repetitive stress fractures, 70% of
the fractures were in the two bones that make up the lower leg; in women, 50%
of the fractures were in the foot and ankle. The majority of patients, 60%,
The researchers found that certain biomechanical factors were
associated with multiple stress fractures, including a high foot arch,
leg-length inequality, and excessive inward turn of the foot. Forty percent of
the fracture-prone women reported menstrual irregularities, compared with about
7% in the control group. Runners with high weekly training mileage were also
found to be at greater risk.
The study runs in the May/June issue of The American Journal
of Sports Medicine.