Background: Calcaneal stress injuries are fairly common overuse
injuries in military recruits and athletes. We assessed the anatomic
distribution, nature, and healing of calcaneal stress injuries in a group of
Methods: Military recruits who underwent magnetic resonance imaging
for the evaluation of exercise-induced ankle and/or heel pain were identified
from the medical archives. The magnetic resonance images, plain radiographs,
and medical records of these patients were evaluated with regard to fracture
type and the natural history of the injury.
Results: Over ninety-six months, magnetic resonance imaging revealed
calcaneal stress injuries in thirty recruits in a population with a total
exposure time of 117,149 person-years, yielding an incidence of 2.6 (95%
confidence interval, 1.6 to 3.4) per 10,000 person-years. Four patients
exhibited a bilateral injury. Of the thirty-four injuries, nineteen occurred
in the posterior part of the calcaneus, six occurred in the middle part of the
calcaneus, and nine occurred in the anterior part of the calcaneus, with 79%
occurring in the upper region and 21% occurring in the lower region. The
calcaneus alone was affected in twelve cases. In twenty-two cases, stress
injury was also present in one or several other tarsal bones. A distinct
association emerged between injuries of the different parts of the calcaneus
and stress injuries in the surrounding bones. In only 15% of the patients was
the stress injury visible on plain radiographs. With the numbers available,
there were no significant differences between the patients with calcaneal
stress injuries and unaffected recruits with regard to age, height, weight,
body mass index, or physical fitness.
Conclusions: The majority of stress injuries of the calcaneus occur
in the posterior part of the bone, but a considerable proportion can also be
found in the middle and anterior parts. To obtain a diagnosis, magnetic
resonance imaging is warranted if plain radiography does not show
abnormalities in a physically active patient with exercise-induced pain in the
ankle or heel.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.