Özet:

One of the most common complications after total hip arthroplasty (THA) is dislocation.To avoid this unpleasant complication, we use constrained systems especially in patients with high risk of dislocation.We report two cases of failure of constrained hip system with intact reinforcement ring.We used Trilogy revision cup in both patients.®The patient refused surgery.Other patients underwent surgery and we observed abrasion of constrained liner because of impingement.Malrotation of the constrained liner appears to cause impingement.When using constrained liners, caution should be exercised against the risk of impingement.Proper assessment of the constrained liner is mandatory.Otherwise, the abrasion of the liner is not a surprise. The instructions of the manufacturer should be followed. The fact that such a small misplacement has such great consequences can also be accepted as a disadvantage of the product. It may be difficult to determine the proper rotation of the polyethylene liner during surgery. Therefore, it would be appropriate to have a wider range of correct polyethylene placement angles.