International Orthopaedics - 2026-04-29 - Journal Article
Monoblock dual-mobility cups in total hip arthroplasty for low-grade hip dysplasia: a retrospective series with a mean ten years follow-up.
Tramini M, Vermorel PH, Stordeur A, Lustig S, Farizon F, Philippot R
Topics
Key Takeaway
Monoblock dual-mobility THA for Crowe I–II DDH achieved 100% implant survival and zero dislocations at mean 10-year follow-up with HHS improving from 48 to 98.
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Summary
This single-center retrospective series evaluated monoblock dual-mobility THA outcomes in Crowe I–II DDH over a minimum 10-year follow-up. All functional scores improved significantly (HHS 48→98, PMA 11→17, Devane 3→4, all p<0.001). No dislocations, aseptic loosening, periprosthetic fractures, or infections occurred, yielding 100% Kaplan-Meier implant survival at 10 years.
Key Limitation
The 25-patient sample is underpowered to detect rare but clinically important complications such as intraprosthetic dislocation or late aseptic loosening, making the 100% survival figure statistically fragile.
Original Abstract
INTRODUCTION
Total hip arthroplasty (THA) for hip developmental dysplasia (DDH) carries a high perioperative complication rate, with dislocation representing the most frequent adverse event. Monoblock dual-mobility (DMM) cups have demonstrated promising results in reducing prosthetic instability while ensuring long-term implant survival. However, data specifically addressing DMM THA in low-grade DDH remain scarce. The aim of this study was to evaluate clinical outcomes and complication rates at a minimum ten-year follow-up in patients undergoing DMM THA for low-grade DDH.
MATERIALS AND METHODS
A single-centre retrospective study was conducted, including all patients who underwent DMM THA for Crowe grade I or II DDH between 2008 and 2018. Clinical outcomes including the Harris Hip Score (HHS), Postel-Merle d'Aubigné (PMA) score, Devane score, visual analog scale (VAS), and range of motion (ROM) were assessed preoperatively, at one year, and at final follow-up. Implant survival was estimated using Kaplan-Meier analysis.
RESULTS
Thirty-one THAs were performed in 25 patients (mean age 55.1 ± 13.4 years; mean follow-up 10.06 ± 1,98 years). All functional scores improved significantly at final follow-up (HHS 48 to 98, PMA 11 to 17, Devane 3 to 4, all p < 0.001). No dislocation, loosening, periprosthetic fracture, or septic complication was recorded. Implant survival was 100% at ten years.
CONCLUSION
The DMM THA for low-grade DDH provides excellent long-term functional outcomes with a remarkably low complication profile, supporting the routine use of DMM cups in this indication.