Sequential scintimetry in prediction of healing rate after femoral neck fracture.

Thirty-one femoral neck fractures which united without complications (nonunion or late segmental collapse) were included in a prospective sequential scintimetric study. Roentgenologically, three subgroups with different healing rates could be distinguished: rapid union, normal union, and delayed union. All fractures showed a rapid increase in relative femoral head radionuclide uptake after the 1-week scintimetry, followed by a gradual decline after 6 weeks-3 months. However, both the initial rise in activity and the time for maximal uptake tended to differ between the three groups. For rapid union and normal union the peak activity was registered at 6 weeks and for delayed union at 3 months. It is concluded that sequential scintimetric assessment of femoral head uptake can identify different healing rates and that this difference can be partly explained by a transient impairment of vascular supply to the femoral head in fractures with delayed healing.