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Meta-Regression Analysis of the Association Between Acetabular Cup Positioning and Functional Outcome for Patients
Nikolai Ramadanov1,2, Maximilian Voss1,2, Robert Hable3
1Center of Orthopaedics and Traumatology, Brandenburg Medical School, University Hospital Brandenburg an der Havel, Brandenburg an der Havel, Germany.
Background:
To examine the association between acetabular cup positioning and functional outcomes, measured with Harris Hip Score (HHS), in IPI patients after THA.
Methods:
A literature search was conducted in PubMed, CENTRAL, Epistemonikos, and Embase up to November 30, 2024. A multilevel random-effects meta-analysis was performed with a restricted maximum likelihood heterogeneity estimator and Hartung-Knapp adjustment. Logistic regression on pooled data identified acetabular cup inclination and anteversion cut-offs associated with IPI, we performed logistic regression analysis on pooled data from the included studies.
Results:
Ultimately, 32 studies with overall 1755 patients were included. The non-IPI subgroup (mean: 91.5; confidence interval [CI]: 88.2-94.9; I2 = 98%; τ2 = 48.7; P < .01) had a higher mean post-THA HHS compared with the IPI subgroup (mean: 83.3; CI: 78.0-88.7; I2 = 96%; τ2 = 48.7; P < .01). The non-IPI subgroup (mean: 42.2; CI: 40.6-43.8; I2 = 97%; τ2 = 10.3; P < .01) had a lower acetabular cup inclination compared with the IPI subgroup (mean: 45.4; CI: 43.3-47.6; I2 = 71%; τ2 = 10.3; P < .01) (F = 6.1; df = 1, 43; P = .02). There was no difference between the 2 subgroups in acetabular cup anteversion (F = 3.8; df = 1, 32; P = .06). There was no significant association between cup inclination (P = .26) or anteversion (P = .67) and post-THA HHS. The optimal cut-offs for cup inclination and anteversion were ≤ 44.1° and ≥ 18.7°, respectively.
Conclusions:
Acetabular cup inclination ≤ 44.1° and anteversion ≥ 18.7° may lower IPI risk following THA. These findings represent a step toward optimizing acetabular cup positioning for a better patient outcome.
