Mid-term results of a cementless primary press-fit cup in acetabular revision surgery

Objectives: In acetabular revision, press-fit acetabular fixation is a commonly used method when the acetabular rim is largely intact and sufficient primary stability can be achieved. However, data on clinical and radiographic results of primary implants in acetabular revision is limited. The purpose of the present study was to evaluate the clinical and radiographic results of a cementless primary press-fit cup in acetabular revision surgery with a minimum follow-up of 5 years.

Methods: This retrospective cohort study evaluated the clinical and radiographic results of 106 consecutive patients (107 hips) in whom a cementless, grit-blasted, non-porous-coated, titanium alloy press-fit cup with flattened pole area and optional screw fixation (Allofit/S ZimmerBiomet, Warsaw, IN) was implanted during acetabular revision for contained acetabular defects (Paprosky type I and II defects, 60 % peripheral cup coverage). Clinical outcome was assessed using the Harris Hip Score (HHS), and patient satisfaction with the procedure was measured on a Likert scale from 1-5. Cup survival for the endpoints revision for any reason (including isolated inlay revisions) and revision for aseptic loosening was estimated using Kaplan-Meier analysis.

Results and Conclusion: At final follow-up, 20 patients (20 hips) had died and 6 patients (6 hips) were lost to follow-up. Mean age at surgery was 64 (range: 28-87) years. Mean follow-up was 9 (range: 5-19) years. Mean acetabular anteversion was 17° (range:1-35°) and mean cup inclination was 39°(range:24-60°). In 54 patients (54 hips) additional screw fixation was used. 10 patients (10 hips) had undergone re-revision of the acetabular component. 2 patients were revised for aseptic loosening, 5 for infection, 2 for recurrent dislocation (1 with isolated change of inlay and neck of femoral stem) and 1 for an adverse reaction to metal debris. Mean HHS before and after revision surgery was 46 (range: 10-98) and 78 (range: 12-100, p < 0,001). Patients reported satisfaction with the operation at a mean of 3.4/5 (range: 1-5). There were no impending revisions at final follow-up. In the radiographic evaluation, 1 patient demonstrated progressive radiographic osteolysis and another patient showed significant polyethylene wear. The estimated 10-year cup survival (17 patients at risk) was 93 % (95 % CI: 83-100) for the endpoint aseptic loosening and 85 % (95 % CI: 74-97) for acetabular revision for any reason, respectively.

Primary cementless press-fit cups provide durable fixation in the mid-term when sufficient primary stability can be obtained during revision. The present cup system demonstrated low re-revision rates rates with few cup related complications and favourable patient reported outcome.

Stichwörter: acetabular revision, cementless, press-fit fixation, allofit cup, 5-year follow-up, Kaplan-Meier analysis

Publication History

Article published online:
15 October 2020