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BIOLOX®delta ceramic-on-ceramic monoblock vs. ceramic-on-polyethylene modular: what 5 years of radiostereometric analysis reveal for ceramic hip replacement

Drs. Caner Içli and Nina M. C. Mathijssen, together with colleagues at the Reinier Haga Orthopaedic Centre and Reinier de Graaf Gasthuis (Netherlands), have published a new randomized controlled trial in Acta Orthopaedica.

BIOLOX®delta CoC monoblock acetabular cup with titanium mesh shell next to a ceramic-on-polyethylene modular cup component.
RSA study design tracking cup migration in 50 THA patients at 7 time points; 25 CoC monoblock vs. 25 CoPE modular cups.
RSA chart: CoC monoblock and CoPE modular acetabular cups both stabilized between 6 weeks and 3 months post-op in THA.
Five-year THA cup translation: 1.54 mm CoC monoblock vs. 0.84 mm CoPE modular; revision rates and PROMs were comparable between groups.
Infographic showing THA clinical outcomes: 1:1 revision rates, improved then stable PROMs, and no osteolysis or loosening reported.

It’s the first radiostereometric analysis (RSA) comparison of these uncemented acetabular components at 5 years’ follow-up: a BIOLOX®delta CoC system with a monoblock cup (Maxera®) versus an uncemented CoXLPE modular cup (Allofit®) from Zimmer Biomet – both paired with a BIOLOX®delta femoral head.

 

A single surgeon operated on 50 patients using a straight lateral approach. RSA and conventional radiographs were taken immediately post-op and at 1.5, 3, 6, 12, 24, and 60 months. PROMs included Harris Hip Score, Oxford Hip Score, EQ-5D-5L.

 

Here’s what they found:

Migration

  • Both cups stabilized between 6 weeks and 3 months, the clinically decisive window for uncemented fixation.

  • Total translation at 5 years was higher for the CoC monoblock (1.54 mm, 95% CI 1.11–1.98) than the CoXLPE modular cup (0.84 mm, 95% CI 0.42–1.26); mean difference –0.71 mm (95% CI –1.31 to –0.10).

  • Translation in both cups stabilized after 3 months.

  • Rotation patterns were statistically comparable between groups.

  • Proximal (y-axis) migration at 2 years was 0.50 mm (CoC monoblock) vs. 0.36 mm (CoXLPE), both within the 0.2–1.0 mm band Pijls et al. (2012) associate with acceptable long-term revision risk.

 

Clinical outcomes

  • No significant differences in revision rates or complication profiles over 5 years.

  • No radiographic signs of osteolysis, loosening, or malpositioning in either group.

  • PROMs improved substantially from baseline and remained stable through follow-up; responder rates on the Oxford Hip Score and HHS moderate-improvement thresholds were comparable at 5 years.

 

The large-head CoC Maxera® monoblock cup delivered mid-term migration and clinical performance comparable to the CoXLPE modular design. Higher early translation did not mean worse fixation or functional outcomes, nor did migration increase the risk of revision.

 

The authors acknowledge that they did not reach a 100% follow-up rate, due partly to the COVID-19 pandemic.

 

📖 Içli C, Hesseling B, Pasma JH, Blom I, Bloem RM, Mathijssen NMC. Migration in large femoral head ceramic-on-ceramic monoblock acetabular component compared with modular ceramic-on-polyethylene acetabular component in total hip arthroplasty using radiostereometric analysis with 5 years' follow-up: A randomized controlled trial. Acta Orthopaedica, 97, 448-455. doi: 10.2340/17453674.2026.46138

 

Please check for regulatory approval in your country.

 

This text reflects CeramTec’s summary of a peer-reviewed scientific publication and does not constitute clinical guidance, risk prediction for individual patients, or product-related recommendations. For product, safety, and risk information, always refer to the labeling of the legal manufacturer. This post was drafted with AI assistance and approved by CeramTec. 

 

Picture used with permission of: Dr. Pascal-Andre Vendittoli

 

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