BACKGROUND: In patients with symptomatic hip impingement, surgical
resection of the femoral head-neck junction may improve the range of motion
and relieve pain. A risk of this procedure is fracture. We evaluated the
amount of resection of the anterolateral aspect of the femoral head-neck
junction that can be done safely.
METHODS: Cadaveric proximal femoral specimens (fifteen matched
pairs) were divided into three groups: 10%, 30%, or 50% of the diameter of one
femoral neck was removed, and the contralateral femoral neck was left intact
to serve as the control. A compressive load was applied directly to the
femoral head. Peak load, stiffness, and energy to fracture were compared among
RESULTS: The energy to fracture differed significantly (p = 0.0015)
among the 10%, 30%, and 50% resection groups. The peak load after the 50%
resection was significantly less (p = 0.0025) than that after the 10% or 30%
resection. With the numbers available, there was no significant difference in
peak load between the 10% and 30% resections.
CONCLUSIONS: Resection of up to 30% of the anterolateral quadrant of
the head-neck junction did not significantly alter the load-bearing capacity
of the proximal part of the femur. However, a 30% resection significantly
decreased the amount of energy required to produce a fracture. Thirty percent
should be considered to be the greatest feasible amount of resection because
of the change in the pattern of the femoral head-neck response to axial loads
that we observed.