Collapsed Subchondral Fatigue Fracture of the Femoral Head

Abstract

KEYWORDS Subchondral fracture Femoral head Collapse

Subchondral stress fracture of the femoral head (SSFFH) is a rarely encountered condition. It occurs not only as an insufficiency-type stress fracture in elderly people or in renal transplant recipients,1–10 but also as a fatigue-type stress fracture in healthy adults.11,12 As in osteonecrosis of the femoral head, which has very similar clinical features and imaging findings,1–6,13–15 collapse of the femoral head can occur in fatigue-type SSFFH.11,12,16 It is well known that once collapse of the femoral head takes place in osteonecrosis of the femoral head, the hip joint deteriorates rapidly and an arthroplasty is eventually necessary in most cases.17,18 However, little is known about the fate of collapsed fatigue-type SSFFH. The authors hypothesized that the fate of collapsed fatigue-type SSFFH probably differ from that of collapsed osteonecrosis of the femoral head because they are similar but quite separate disease conditions. The authors expected a much better prognosis in collapsed subchondral stress fractures because they have an intact blood supply and healing potential. In this study, the authors retrospectively evaluated the clinical course of collapsed fatigue-type SSFFH in nine patients.