Abstract
BACKGROUND: Revision total hip arthroplasty (THA) in the presence of severe acetabular bone loss remains technically demanding. Oversized, highly porous acetabular components ("Mega Cups") have been introduced to maximize host bone contact, enhance biological fixation, and restore the anatomical hip center. METHODS: A retrospective study was conducted between 2014 and 2022, including 34 hips reconstructed with highly porous Mega Cups for Paprosky type II and selected type III defects. Clinical outcomes (Harris Hip Score [HHS], WOMAC, pain VAS), radiographic stability, complications, and implant survivorship were analyzed at mid-term follow-up. RESULTS: At a mean follow-up of 5.3 years, Mega Cups demonstrated 95.5% survivorship. Radiographic stability was achieved in 90.9% of hips, with graft incorporation observed in 88.9%. Functional recovery was substantial: HHS improved by +34.4 points, WOMAC decreased by -37.8, and pain VAS declined by -4.8 (all p < 0.001 vs. baseline). Subgroup analysis confirmed excellent outcomes in Paprosky II defects and in patients aged 40-65 years. Complication rates were low, with dislocation (2.9%), mechanical failure (2.9%), superficial infection (8.6%), and thromboembolism (2.9%) within published benchmarks. CONCLUSION: Highly porous oversized acetabular cups provide reliable fixation, durable mid term survivorship, and superior functional improvement in revision THA for Paprosky II and selected III defects. Their ability to maximize host bone contact and reduce reliance on grafts makes them a dependable option in complex acetabular reconstructions. Longer multicenter studies are warranted to validate durability beyond 10 years and to benchmark outcomes against alternative strategies.