Implant failure of the gamma nail.

The gamma nail is a temporary implant characterised by a limited life expectancy under continuous dynamic stress. We reviewed a series of 839 patients with gamma nail stabilisation and found two fatigue fractures (0.2%) at the aperture of the distal locking holes. This complication has not been described in the literature. Metallurgic and scanning electron microscopic examinations proved that the fatigue zones occurred at the clover-leaf grooves, which is where the diameter of the gamma nail is reduced. The clover-leaf diameter is of no biomechanical use in gamma nail stabilisation. We suggested product modification of the gamma nail to produce implants with a round diameter instead of a clover-leaf shape. A modified implant is already in use at our institution.