Key takeaways
- Total hip arthroplasty is highly successful, but prosthetic joint infection remains a clinically important complication and a leading cause of revision1
- In a US database analysis, OXINIUM◊-on-polyethylene bearings were associated with lower rates of infection or inflammatory reaction diagnoses than metal-on-polyethylene bearings up to 2 years after primary THA1
- In a bespoke National Joint Registry (NJR) report from England, Wales, and Northern Ireland, OXINIUM femoral heads with highly cross-linked polyethylene (XLPE) liners were associated with lower adjusted risk of revision for infection compared with metal/XLPE and ceramic/XLPE2
- Linked NJR/HES data broaden the evidence discussion beyond infection, with OXINIUM bearings associated with lower revision risk and lower aseptic loosening risk in key comparative analyses3
Why does this matter for surgeons?
Total hip arthroplasty (THA) is widely recognised as a highly successful procedure. Yet prosthetic joint infection (PJI) remains one of the most challenging complications in arthroplasty. For surgeons and healthcare systems, infection-related revision can be clinically complex, resource intensive and difficult to manage. For patients, it can disrupt the expected recovery trajectory after an otherwise successful primary procedure.
PJI remains a major risk after THA, and Schaffler et al. note that PJI rates have remained essentially static over the last 2 decades. Although recognised patient risk factors, including high BMI, diabetes and smoking status, have been identified and targeted, further improvements are still needed. As THA volumes continue to rise, understanding which other factors are associated with infection-related outcomes becomes increasingly relevant.1
Bearing selection has traditionally been discussed in relation to wear, survivorship and local tissue response. Those remain important considerations. However, newly published and registry-based data now add infection-related outcomes to the wider evidence conversation around bearing selection in THA.
Three real-world datasets:
New evidence from the US: are infection-related differences seen early after primary THA?
Schaffler et al. analysed 123,698 primary THA patients from the Premier PINC AI Healthcare Database (PINC AI) between 2017 and 2022. Following propensity score matching, OXINIUM-on-polyethylene bearings demonstrated lower rates of infection or inflammatory reaction diagnoses than metal-on-polyethylene bearings at every assessed timepoint from 1 month to 2 years after surgery (see figure below).1
Importantly, when diagnosis codes were validated using hip imaging procedures, rates remained lower with OXINIUM-on-polyethylene than metal-on-polyethylene bearings.1
The ceramic-on-polyethylene comparison was more nuanced. Lower rates of infection or inflammatory diagnosis were observed during the first 6 months, although differences were no longer statistically significant at 1 and 2 years using diagnosis codes alone. When diagnoses were cross-referenced with imaging procedures, OXINIUM-on-polyethylene bearings remained associated with lower overall infection and inflammation rates than ceramic-on-polyethylene.1
Long-term evidence from the NJR: does the signal extend to revision for infection?
A clinically important follow-up question is whether infection-related findings are also seen in long-term registry data where the endpoint is revision for infection.
A bespoke National Joint Registry (NJR) report evaluated more than 887,000 primary THA procedures with up to 20 years of follow-up. In this analysis, OXINIUM/XLPE bearings were associated with a 24% lower adjusted risk of revision for infection compared with metal/XLPE (adjusted hazard ratio [HR] 0.76; p=0.008). OXINIUM/XLPE bearings were also associated with a 20% lower adjusted risk of revision for infection compared with ceramic/XLPE (adjusted HR 0.80; p=0.016).2
These two analyses answer related but different questions. The Premier PINC analysis assessed infection- and inflammatory-related diagnoses in a US hospital database up to 2 years after surgery. The NJR report assessed revision for infection over long-term registry follow-up in England, Wales and Northern Ireland. Taken together, they provide complementary real-world evidence associating OXINIUM femoral heads paired with polyethylene liners with lower infection-related outcomes compared with selected conventional bearing combinations.1,2
Looking beyond infection: what else do linked registry data show?
Infection-related outcomes are only one part of implant performance. A further question for surgeons is whether OXINIUM bearing data also contribute to the broader discussion of revision, aseptic loosening and reoperation burden.
Davis et al. analysed linked NJR and Hospital Episode Statistics (HES) data in 696,013 THAs with 17,468 reoperations. Average follow-up ranged from 4.83 to 9.64 years depending on bearing combination, with maximum follow-up of 19.1 years across all bearings.3
This analysis linked NJR data with polyethylene manufacturing characteristics and HES data. This allowed capture of ipsilateral internal fixation procedures for periprosthetic hip fractures where the implant was not revised, capturing a broader view of reoperation than revision-only analyses.3
As shown in the above table, in the regression analysis versus metal-on-polyethylene, OXINIUM bearings had the lowest risk of revision for any reason, followed by ceramic on antioxidant XLPE.3 Among contemporary bearings, with metal-on-XLPE as the reference, OXINIUM bearings again had the lowest risk of revision for any reason, followed by ceramic on antioxidant XLPE.3
Davis et al. also reported that OXINIUM bearings had the lowest risk of revision for aseptic loosening among contemporary bearings, followed by ceramic on antioxidant XLPE.3
What can surgeons take from these findings?
Although these findings do not establish causation, they invite a wider discussion about bearing material, infection-related outcomes and implant performance after THA. What makes the evidence noteworthy is the consistency of the signal across different real-world datasets.
The evidence does not make bearing selection an infection-prevention strategy in isolation, but it does broaden the conversation. For surgeons evaluating THA bearing outcomes, the question is no longer limited to wear and survivorship. These real-world analyses suggest that infection-related outcomes and reoperation burden also warrant consideration within the overall evidence base for bearing selection in THA.
These are observational analyses, so interpretation should remain balanced. Registry and administrative datasets can identify important associations, but cannot account for every potential confounding factor. In the linked NJR/HES analysis, Davis et al. also note that as a single-company product, OXINIUM Technology is used within a limited range of femoral and acetabular constructs, which may contribute to the observed findings.3 Even so, the consistency of the evidence suggests that OXINIUM Technology warrants attention as part of the broader evidence conversation around bearing selection and THA outcomes.
The next question: why have lower infection-related outcomes been observed with OXINIUM bearings across these real-world datasets?
To hear an expert perspective on the data and the authors’ proposed hypothesis, watch the video with Prof. Davis below:
