JOA - 2026-06-09 - Journal Article
Comparing Clinical and Radiological Outcomes for a Three-Dimensional Printed Highly-Porous Cup and a Hydroxyapatite-Coated Non-Highly-Porous Cup in Total Hip Arthroplasty Using Propensity Score Matching.
Okazaki T, Imagama T, Matsuki Y, Kaneoka T, Kawakami T, Sakai T
Topics
Key Takeaway
3D-printed highly porous cups had a significantly higher initial gap rate than HA-coated non-highly-porous cups (27.3% vs 12.1%, P=0.027), but both demonstrated equivalent clinical scores and zero migration or loosening at 2 years.
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Summary
This study compared 3D-printed highly porous acetabular cups to HA-coated non-highly-porous cups in CT-navigated THA using propensity score matching (66 hips per group). JOA and JHEQ scores improved equivalently in both groups at 6, 12, and 24 months, with no migration or loosening in either cohort. Initial gap incidence was significantly higher in the 3D-printed group (27.3% vs 12.1%, P=0.027), though gaps resolved radiographically by 2 years.
Key Limitation
Two-year follow-up cannot determine whether the higher initial gap rate in the 3D-printed group translates into differential loosening or failure rates at mid- to long-term follow-up.
Original Abstract
BACKGROUND
The use of highly-porous acetabular components in total hip arthroplasty (THA) has gained popularity. To elucidate the clinical and radiological outcomes of three-dimensional (3D)-printing highly porous cups, we compared highly-porous cups and hydroxyapatite (HA)-coated non-highly-porous cups in computed tomography (CT)-based navigated THA.
METHODS
We retrospectively investigated 196 hips of 175 patients (the highly-porous group, 112 hips of 97 patients; the HA-porous group, 84 hips of 78 patients) who underwent THA using a CT-based navigation system. After propensity score matching for age, sex, diagnosis, and surgical approach, each group comprised 66 hips. Clinical outcomes were evaluated using the Japanese Orthopaedic Association hip (JOA) score and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) score preoperatively and at six, 12, and 24 months postoperatively. Radiological outcomes for cup orientation, positioning, initial gap, migration, loosening, and radiolucent line (RLLs) were assessed. Cup placement was measured using 3D templating software.
RESULTS
Clinical outcomes did not differ significantly between groups after two years. The mean absolute error of cup orientation did not differ significantly between the two groups (inclination: 2.9 ± 2.3° versus 2.6 ± 2.2°, respectively; anteversion: 2.7 ± 2.0° versus 2.7 ± 2.0°, respectively). There was no migration or loosening in both groups during the study period. The incidence of initial gap was significantly higher in the highly- porous group than in the HA-porous group (18 of 66 cases, 27.3% versus eight of 66 cases, 12.1%, P = 0.027). The RLLs exhibited progressive decline during the two-year follow-up in both groups, and there were no significant differences at two years.
CONCLUSION
The two-year clinical outcomes and radiological evaluations of the 3D-highly porous and non-highly-porous cups were comparable. Initial gaps in the 3D-printing highly porous cups diminished, and the highly porous cups showed excellent radiological outcomes.