Minimum Five-Year Results of Acetabular Revision Using Uncemented Monoblock Dual-Mobility Cups for Moderate to Severe Bone Loss.

Abstract

Acetabular revision in the setting of moderate to severe bone loss is associated with high risks of instability and mechanical failure. Uncemented monoblock dual-mobility (UMDM) cups combine biological fixation with enhanced stability, but data beyond five years in complex revision settings remain limited. This study evaluated implant survivorship, complications, and clinical and radiographic outcomes of an UMDM cup used for acetabular revision with moderate to severe bone loss. This retrospective single-center study included 60 acetabular revisions performed between 2009 and 2019 using an uncemented monoblock dual-mobility cup in patients who had Paprosky ≥ IIA defects and a minimum follow-up of five years. The primary endpoint was aseptic acetabular loosening. The secondary endpoints included acetabular re-revision, complications, functional outcomes (Harris Hip Score [HHS], Postel-Merle d'Aubigné [PMA]), and radiographic assessment of acetabular reconstruction, including restoration of the hip center of rotation. The mean follow-up was 8.6 years (range, 0 to 15.3), with a mean patient age of 77 years (range, 44 to 91). Bone loss was classified as Paprosky IIA (23%), IIB (30%), IIC (33%), IIIA (5%), and IIIB (8%). There were six hips (10%) that met criteria for aseptic loosening, including four requiring revision. Implant survivorship free from revision for aseptic loosening was 100% at five years and 93.0% at 10 years (95% CI [confidence interval], 85.7 to 100). Survivorship free from revision for any cause was 98.2% at five years and 84.6% at 10 years (95% CI, 74.5 to 96.0). The dislocation rate was 5%, with no recurrent instability. Radiographic analysis demonstrated satisfactory restoration of the hip center of rotation in most cases. Functional outcomes improved significantly, with a mean HHS of 89 ± 7 and a PMA score of 16.9 ± 1.6. The use of UMDM cups provided reliable fixation and stability in acetabular revision for moderate to severe bone loss, with low dislocation rates and satisfactory reconstruction quality at a minimum five-year follow-up.