Total Hip Arthroplasty After Dynamic Hip Screw Failure: Descriptive Results of a 10 Years Retrospective Study

Background: One of implants which is used for fixation of hip fracture (HF) is dynamic hip screw (DHS). Because of the destruction of the head of femur, or even acetabulum, during the cut out process or because of severe osteoporosis, refixation of fracture may be impossible. In this time, total hip arthroplasty (THA) is a good option. Objectives: In this study, we try to retrospectively evaluate the results THA after DHS failure. Materials and Methods: This retrospective study was undertaken in Sina hospital, Tehran, Iran, from 2004 to 2014, and included all patients with intertrochanteric HF which was initially fixed with DHS and failed, that was further treated with THA. Results: In the total of 52 patients, nail cut out was responsible for 49 cases (94%) of DHS failure, whereas in three cases (6%) it was the fracture of the side plate. Pre-operative Harris hip score ranged from 30 to 50 (average 36) and post-operative score ranged between 65 and 90 (average 85). There were 12 cemented cups and 40 cementless cups. Fourteen standard stem and 38 long stem were used. Twelve of the 14 standard stems were cemented. Posterior approach was used in 45 cases and direct lateral approach was used in the remaining seven cases. Prophylactic wiring was done in 46 cases. Intraoperative penetration of the floor of acetabulum occurred in two cases. Constrained liner was necessary in five cases, three of which because of sever osteoporosis of trochanter and insecure fixation of it after fracture and two because of recurrent dislocation. Conclusion: For achieving good results, the THA, after failure of DHS, requires the use of posterior approach, extremely careful acetabular reaming, prophylactic wiring of femur and the passing of the holes of screws with long stems.