JOA - 2026-04-30 - Journal Article
Uncemented Monoblock Cups in Primary Total Hip Arthroplasty: Average 10-year Follow-up.
Meding LK, Luo TD, Buller LT, Deckard ER, Meneghini RM, Meding JB
Topics
Key Takeaway
Uncemented monoblock cups in primary THA achieved 10-year survivorship of 98.8% for any cup revision and 99.2% for aseptic loosening, with a dislocation rate of only 0.1% across 2,292 hips.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This study evaluated 10-year outcomes of uncemented monoblock cups (56% LDMOM, 44% dual mobility) in primary THA performed between 2005 and 2022. Kaplan-Meier analysis demonstrated 10-year survivorship of 98.8% for any cup revision, 99.2% for aseptic loosening, and 99.3% for aseptic cup revision, with only 3 dislocations (0.1%) and 14 radiographically loose cups (0.6%). Nine of the 14 loose cups were associated with LDMOM metallosis, reinforcing the decline of that bearing surface while supporting continued use of monoblock cups with dual mobility articulations.
Key Limitation
The LDMOM cohort (56% of cases) confounds survivorship analysis because metallosis-driven loosening inflates cup failure rates unrelated to fixation quality, making it difficult to isolate true aseptic loosening attributable to the monoblock design itself.
Original Abstract
INTRODUCTION
The use of large diameter metal-on-metal (LDMOM) heads and dual mobility articulations (DM) has reduced the risk of dislocation after primary total hip arthroplasty (THA). Furthermore, the monoblock cup versions eliminate the risks associated with modularity, such as corrosion. The purpose of this study was to determine the average 10-year outcomes and survivorship of modern uncemented monoblock cups (UMCs) in primary THA.
METHODS
Between 2005 and 2022, 2,292 primary THAs were performed using UMCs. There were 1,288 LDMOM articulations (56%), and 1,004 were DM (44%). The mean age at operation was 64 years (range, 29 to 92), and 57% of the patients were men. Patients were routinely followed with Harris Hip Scores (HHS) and serial radiographs. Kaplan-Meier survival was determined for cup revision and aseptic loosening. All patients were followed for a minimum of two years. The mean follow-up was 10.8 years (range, two to 20).
RESULTS
At the final follow-up, HHS and pain scores averaged 89 and 42, respectively. There were three dislocations (0.1%), all of which underwent successful closed reduction, and 10 deep postoperative infections (0.4%), all of which underwent staged revisions. There were 14 loose cups (0.6%) identified, nine associated with LDMOM metallosis and two with DM articulations, of which 13 were revised. All of the other cups were deemed radiographically stable. There were five additional cups revised secondary to metallosis. The 10-year survivorship was 98.8% for any cup revision, 99.2% for aseptic cup loosening, and 99.3% for aseptic cup revision.
CONCLUSION
Using UMCs in primary THA has provided excellent clinical results and survivorship at mid-term follow-up, with a very low dislocation rate. Although LDMOM use has fallen out of favor, UMCs still afford durable implant fixation, negating the concern over modular cup corrosion when coupled with DM articulations.