Subtrochanteric fractures treated with interlocking nailing. In a prospective study of 31 subtrochanteric fractures treated with Grosse-Kempf interlocking nails with a followup period of at least 1 year, there was a 87.1% (27/31) union rate, and a union period of 4.2 +/- 1.8 months. Knee range of motion in 28 acute traumatic cases was on average 127.5 +/- 23.0 degrees. The significant complications included: nail breakage, 3.2% (1/31); nonunion without nail breakage, 9.7% (3/31); neglected femoral fracture with malunion, 3.2% (1/31). The interlocking nailing has the advantages of: a) closed method, b) weight-sharing principle, c) shortening prevention, d) non-rigid fixation. From the theoretical and clinical comparison among the various implants, we conclude that closed interlocking nailing is one of the better instruments for subtrochanteric fracture treatment, and moreover, the most reasonable of all. However, for the higher level subtrochanteric fractures, reconstruction-style locking nails should be chosen. 