Acetabular stress fractures in military endurance athletes and recruits: incidence and MRI and scintigraphic findings.
OBJECTIVE
To evaluate the incidence and the MRI and scintigraphic appearance of acetabular stress (fatigue) fractures in military endurance athletes and recruits.


METHODS
One hundred and seventy-eight active duty military endurance trainees with a history of activity-related hip pain were evaluated by both MRI and bone scan over a 2-year period. Patients in the study ranged in age from 17 to 45 years. They had hip pain related to activity and had plain radiographs of the hip and pelvis that were interpreted as normal or equivocal. The study was originally designed to evaluate the MRI and scintigraphic appearance of femoral neck stress fractures. Patients had scintigraphy and a limited MRI examination (coronal imaging only) within 48 h of the bone scan. Twelve patients demonstrated imaging findings compatible with acetabular stress fractures.


RESULTS
Stress fractures are common in endurance athletes and in military populations; however, stress fracture of the acetabulum is uncommon. Twelve of 178 patients (6.7%) in our study had imaging findings consistent with acetabular stress fractures. Two patterns were identified. Seven of the 12 (58%) patients had acetabular roof stress fractures. In this group, two cases of bilateral acetabular roof stress fractures were identified, one with a synchronous tensile sided femoral neck stress fracture. The remaining five of 12 (42%) patients had anterior column stress fractures, rarely occurring in isolation, and almost always occurring with inferior pubic ramus stress fracture (4 of 5, or 80%). One case of bilateral anterior column stress fractures was identified without additional sites of injury.


CONCLUSIONS
Stress fractures are commonplace in military populations, especially endurance trainees. Acetabular stress fractures are rare and therefore unrecognized, but do occur and may be a cause for activity-related hip pain in a small percentage of military endurance athletes and recruits.
Williams
T R
TR
Portsmouth Naval Medical Center, Radiology Department, Charette Health Care Center, 27 Effingham Street, Portsmouth, VA 23708-2197, USA. ikewms1@aol.com
Puckett
M L
ML
Denison
G
G
Shin
A Y
AY
Gorman
J D
JD
D000077:Acetabulum / Q000293:injuries*; D000328:Adult; D005260:Female; D015775:Fractures, Stress / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D010807:Physical Endurance; D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate; D015899:Tomography, Emission-Computed, Single-Photon; D014481:United States
D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate