Femoral neck fractures. 121 cases treated by Knowles pinning.

The femoral neck fracture remains one of the unsolved fractures. It is a fracture with a high incidence of nonunion and avascular necrosis. One hundred twenty-one mostly young adult patients with femoral neck fractures were treated by Knowles pins internal fixation. Patients were observed for an average of 32 months following surgery. Union occurred in all Garden Stage I and II undisplaced fractures, and the incidence of nonunion was 14% in Garden Stage III and IV displaced fractures. The incidence of avascular necrosis was 5.9% in undisplaced fractures and 34.5% in displaced fractures. There was no significant difference in avascular necrosis rates among age groups. Nonunion and avascular necrosis occurred mainly in displaced fractures. Knowles pinning offers the advantages of few technical failures, early weight bearing, high union rate, and low complication rate.