JOA - 2026-05-01 - Journal Article
Surgical Approach Does Not Influence Instability Risk in Primary Total Hip Arthroplasty With Monobloc Dual Mobility Cup.
Machado A, Foissey C, Abdelatif EA, Batailler C, Lustig S
Topics
Key Takeaway
In 1,378 primary THAs using monobloc dual-mobility cups, dislocation rate was 0% with DAA versus 0.4% with posterolateral approach, a non-significant difference (P=0.16).
Summary Depth
Choose how much analysis to show on this article page.
Summary
This study asked whether surgical approach influences dislocation risk when a monobloc dual-mobility cup is used in primary THA. 824 DAA and 554 PLA cases from a single center (2010–2022) were analyzed retrospectively for dislocation and complications. Dislocation occurred in 0 DAA cases and 2 PLA cases (0.4%), a non-significant difference; however, the PLA group had more femoral fractures and comprised an older, heavier, higher-ASA population.
Key Limitation
Non-randomized design with systematic baseline differences between approach groups—PLA patients were older, more obese, and higher ASA—making complication rate comparisons unreliable and introducing selection bias that cannot be adjusted for without propensity matching.
Original Abstract
BACKGROUND
The impact of the surgical approach on the risk of dislocation in total hip arthroplasty (THA) remains controversial, particularly when monobloc dual mobility cups (DMCs) are used. This study aimed to compare dislocation and complication rates between the postero-lateral and direct anterior approaches (DAAs) with a DMC in primary elective THA, based on data collected from a single center.
METHODS
Between 2010 and 2022, 1,378 consecutive primary THAs were performed using a monobloc DMC. There were 824 performed by DAA and 554 by postero-lateral approach (PLA). Exclusion criteria were cemented implants, patients treated for femoral neck fracture, developmental hip dysplasia, osteosynthetic complications, and follow-up of less than one year. Complications and revisions were analyzed retrospectively. The mean follow-up was 39 months (range, 12 to 157).
RESULTS
There was no statistically significant difference between the risk of dislocation with the anterior approach (n = 0; 0%) compared with the posterior approach (n = 2; 0.4%) (P = 0.16). There were more major complications, such as femoral fractures, in the PLA group in an older, more overweight, and higher American Society of Anesthesia score population.
CONCLUSIONS
In total hip arthroplasty using monobloc DMCs, the dislocation rate with the PLA is no higher than with the DAA. The low incidence of dislocations in this large cohort supports the benefits of using monobloc DMCs.
LEVEL OF EVIDENCE
3, Retrospective Cohort Study.