Introduction and Objectives: Dislocation is a frequent and severe complication of primary total hip replacement (THR). When there is great joint instability or when there is failure of previous treatments, constrained acetabular liners may be indicated. We wish to make known our experience with this type of implant.

Materials and Methods: We carried out a retrospective study of 2,065 primary THRs carried out over 8 years (1999–2007), we found 81 cases of dislocation and in 10 patients a constrained acetabular component was implanted. We assessed the number of procedures and the risk factors. We placed Ringloc^® Constrained Acetabular Liners in 3 patients and a constrained type R in the other 7 patients. Follow-up was carried out for 3.5 years in one case and 19 and 4 months in the other.

Results: The 3 patients with the longest follow-up in which we placed Ringloc^® Constrained Acetabular Liners evolved favorably. The 7 patients in which we placed R acetabular system constrained liners presented 5 cases of dislocation (2 patients with 2 episodes). Closed reduction was achieved on 3 occasions and on 2 occasions open reduction was used. We wish to highlight the fact that one contention ring suffered rupture. Two patients required the re-implantation of a new retention model.

Discussion and Conclusions: It would seem that constrained acetabular liners are a good option for the treatment of extreme joint instability and the neuromuscular problems that give rise to it. Constriction, as has been reported, has the disadvantage of the difficulty, although not impossibility, of reduction, as we have seen. It also has the disadvantage of suffering greater wear. Our experience with an implant model has been unsatisfactory, with a 70% rate of re-dislocation.