[Poor results in 183 threaded acetabular cups at a mean 7 years follow-up].

We reviewed 183 threaded rings at a mean 7 years follow-up. Poor résults are frequent: 34 % had been revised and 50 % have radiographic migration, essentially with proximal migration of the cup. Generally, we reoperated with other cememtless implants. The type of threaded cup does not matter (spheric or conic). Only the duration of follow up seems significant. We think that biomecanical strains, rather than physiology, explain these numerous migrations. We have therefore abandoned threaded cups in favour of porous-coated impacted cups.