Long-term results of Zweymüller SLL femoral stem in revision hip arthroplasty for stage II and IIIA femoral bone defect: a 9-15-year follow-up study.

Background: Loosening of femoral stem can be associated with a wide spectrum of bone loss that represents the most important factor for choosing the most appropriate revision implant. Positive outcomes in femoral revision were already observed with Zweymüller Alloclassic SLL stem in short- and medium-term follow-up. The aim of the study is to analyse the clinical results of 31 patients who underwent prosthetic revision for aseptic loosening of femoral component with Zweymüller femoral stem and long follow-up.

Methods: The series included 10 men and 21 women with a mean age of 66.24 years at the time of revision surgery and a mean follow-up of 12.25 years. Clinical and radiological evaluation was performed at 2 months, 6 months and yearly, using Harris Hip Score (HHS) and Engh's criteria and Brooker classification for heterotopic ossifications.

Results: At the last follow-up, the survival of the stem was observed in all patients (32 hips). The mean HHS was 77.83 ± 20.90. Clinical results were stated as excellent in 14 cases, good in 5 cases, fair in 4 cases and poor in 9 cases. Radiographic stability with fixation by bone ingrowth was observed in 15 cases and with fibrous ingrowth in 17 cases. Heterotopic ossifications grade III was observed in 4 cases and grade II in 3 cases.

Conclusions: Zweymüller Alloclassic SLL stem showed excellent or good results in about 59% of revision surgery for aseptic loosening. The survival rate of the stem at 9-15 years of follow-up was satisfactory.