Fate of subchondral fatigue fractures of femoral head in young adults differs from general outcome of fracture healing.

PURPOSE: The purpose of this study is to report the clinical course of fatigue-type subchondral fractures of the femoral head in young healthy adults.

MATERIALS/METHODS: We retrospectively reviewed 28 consecutive patients (34 hips) who had a clear history of a sudden increase in physical activity without trauma on the hip and pelvis, and were diagnosed as having a fatigue-type subchondral fracture of the femoral head. The diagnosis was made primarily on the basis of sequential plain radiographs and magnetic resonance images.

RESULTS: Of the 34 hips, 19 hips with no bony collapse experienced gradual disappearance of subjective pain a few months after onset, and there were no recurrences. Other 2 hips that showed bony collapse, but preserved the articular margin, also experienced no definite deterioration of collapse or arthritic change and did not need surgical intervention. In the remaining13 hips with bony collapse and destroyed articular margin or arthritic change, hip pain gradually worsened necessitating surgery.

CONCLUSIONS: The current findings suggest that a subchondral fatigue fracture of the femoral head could show a different severity of subchondral injury over time. In the collapsed subchondral fatigue fractures, especially when combined with head incongruency, the hip pain was aggravated enough to require surgical intervention.