Abstract:

BACKGROUND: The femoral head/neck junction is preserved in hip resurfacing, so femoral head/neck junction could be at great risk of notching, leading to postoperative femoral neck fracture.
OBJECTIVE: To analyze the contour of femoral head/neck junction in hip resurfacing surgery.
METHODS: Three dimensional CT images were collected from 102 healthy hips. The very cross section which was perpendicular to the long axis of femoral neck was obtained to make an angle of 50° (or 45°, 55°) with femoral shaft through the femoral head/neck junction. The medial-lateral length (a) and anterior-posterior length (b) were measured. A best-fit circle was created to the outer cortex of the section, and a point (point A) most close to the circle at the lateral part of cortex was identified. A line from point A to the circle centre was created to measure the angle (angle α) made of this line and the horizontal line. The medial-lateral length (a) and anterior-posterior length (b) was compared. The angle α and influencing factors were calculated.
RESULTS AND CONCLUSION: Medial-lateral length (a) was significantly greater than anterior-posterior length (b), and male was > female. The mean angle α was 27°. There were no correlation between the angle α and length, body mass or gender. Notching is more possible to occur at superior-lateral or inferior-medial side, and is most possible to occur at “superior-lateral-anterior” part. Point A is 27°anterior to the horizontal line. Surgeons should pay much attention to protect it.