Total hip arthroplasty is a common surgical procedure undertaken to relieve pain and
restore function. According to recent data, more than 182 hip procedures per 100,000 population were performed in the OECD countries in 2017. The hip procedure rates increased by 30% between 2007 and 2017 and they are expected to rise in future following the growing incidence of osteoarthritis due to the sociodemographic changes and the aging population. The increase of multi-morbidity cases contributes significantly to this trend.1
Healthcare systems are currently facing challenges in financing and provision of medical services and will do so even more in the future. In the face of these epidemiological and health economic developments, the choice and efficiency of the medical intervention are becoming essential in the long-term. In total joint arthroplasty, the choice of the implant material increasingly plays a pivotal role.
International registries show a growing trend in the use of ceramics in primary hip procedures. Ceramic components are perceived as a reasonable choice. Countries like Italy, Germany, France or Korea adopted ceramics very early on, however, in other countries like the USA or in the UK, only recent issues and concerns about fretting corrosion led surgeons to use ceramics instead of CoCr heads.2-9
Even though modern biomedical research and constant development of orthopedic implants improved their function over time, some challenges still need to be tackled. Among the most common reasons for revision in TJA, are aseptic loosening, infection, dislocation, periprosthetic fracture and pain. Although these complications are mostly associated with uncertain etiology the bearing material play an important role in this context.
Several factors besides the implant material determine the clinical outcome of a TJA surgery, including patient-specific factors, such as gender, age, living habits or the disease history. Before operating a patient, surgeons will look at each case individually and make sure that patient’s risk factors are taken into consideration when choosing the right treatment regime.
A recent observational prospective study (Geneva Arthroplasty Registry, Switzerland) investigated the dependencies between patient smoking habits, bearing material and the risk of revision in THA. The study revealed that the use of metal bearings is associated with a high failure rate, especially in ever-smokers (compared to never-smokers). In contrast, low failure rates with ceramic-on-polyethylene bearings were not associated with the smoking habits (ever smoker vs. never-smoker).12
Ceramic bearings possibly do not compromise the patient’s health status even if the patient is already at a risk (e.g. smoking habits).
Adverse reactions to TJA-implants can be related to fretting and corrosion or wear and particulate debris (especially metal), which can trigger local or even systemic tissue inflammatory reactions. Bone, muscles and nerves surrounding the implant can be extensively damaged, finally leading to a revision surgery for adverse reaction to metal debris (ARMD).
ARMD include local and systemic tissue reactions and can manifest in the form of osteolysis, necrosis, pseudotumor or fibrous capsules and can incorporate elevated blood/serum metal ion levels and metallosis. ARMD and trunnionosis are often accompanied by a high risk of serious complications and have also been associated with the development of hypersensitivity.
Although clear implant-related metal toxicities are rare, the clinical findings in patients with high metal ion levels and particle concentrations are devastating and have shown to be associated with an enhanced risk for the development of periprosthetic infection, inflammation, local tissue toxicity, carcinogenicity, and genotoxicity.
Ceramics are safe in terms of metal ion release13 and pathogenic reactions to ceramic particles are unlikely14. Even if metallosis and hypersensitivity remain rare, ceramic heads may be especially indicated in cases where the use of CoCr heads might compromise the health of the patients, as in patients with comorbidities, with impaired renal function or known metal hypersensitivity.
Mechanically Assisted Crevice Corrosion (MACC) in modular total hip arthroplasty was identified as a clinical concern already in the 1980s-90s. Design trends like metal-on-metal and metal-on polyethylene bearings with large heads and modular necks have re-introduced implant corrosion at the junction taper as a clinical issue, being the cause for 8.2% of all revisions11 and often with serious consequences.
This concern led many surgeons to rethink their treatment algorithm and eliminate the use of CoCr head by replacing them with ceramic heads. Ceramic heads have proven to be very effective at limiting corrosion thus mitigating the generation of toxic byproducts. Studies by Kocagoz13 and a recent meta-analysis by Wight et al.15 show that the use of ceramic heads mitigates the problem of fretting corrosion and is therefore a reasonable option.
In-vitro studies have shown that bacteria adhere less on ceramic surfaces. Researchers of the University of Bristol investigated how this observation transfers into clinical outcomes. In their study published in the LANCET, Lenguerrand, Whitehouse, and co-authors investigated the risk factors and their correlation and impact on the risk for revision due to PJI. The factors investigated were patient-derived factors such as age, gender, etc., health system-derived factors such as place of surgery, operating surgery volume, etc. and surgery-specific factors such as osteoarthritis, fracture of femoral neck, etc. In this study, bearing type was also assessed and thus, the investigation of the impact of bearing material on PJI.16
Despite patient-related factors such as elevated BMI, diabetes, male sex and others, metal bearings were identified as a risk factor for a revision because of PJI.
Dislocation is one of the major causes of revision after primary THA accounting for about 15% of all revisions in the UK National Joint Registry. It is an early complication, and patients who suffer from a first dislocation will likely experience one or more further dislocations. Dislocation patients seem to benefit from ceramic bearings. One of the reasons is that ceramic allow to increase the head diameter and optimize the range of motion without increasing wear17. Studies suggest that Ceramic-on-Ceramic bearings may be associated with less late dislocations than polyethylene bearing surfaces18.
In-vitro and in-vivo studies are showing evidence that ceramic is able to “perform its desired function”, “generate an appropriate cellular or tissue response” and “is not likely to elicit adverse local or systemic effects in the host”. Accordingly, ceramics comply with Williams' definition of biocompatibility confirmed at the Chengdu consensus conference in 2018.19 What does it mean for the clinical performance of ceramics? Most arthroplasty registries from all over the world confirm that the use of ceramic heads is associated with lower rates of revision compared to metal heads.20-24
1. OECD (2019), Health at a Glance 2019: OECD Indicators, Paris: OECD Publishing; 2019:198. doi:10.1787/4dd50c09-en. Accessed November 5, 2020.
2. Svenska Höftprotesregistret. Årsrapport 2019. 2020:53 (Figure 6.6.1).
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11. National Joint Registry for England, Wales. Northern Ireland and the Isle of Man, 17th Annual Report 2020. Surgical data to 31 December 2019. ISSN 2054-183X (Online) 2020:114 (Tables 3.H17a).
12. Gonzalez A, Garavaglia G, Peter R, Hoffmeyer P, Hannouche D, Lübbeke A. Influence of smoking status on risk of revision after primary total hip arthroplasty is bearing-dependent. In: Proceedings from 8th International Congress of Arthroplasty Registries; June 1-3, 2019; Leiden, Netherlands. 2019; Abstract No. 39.
13. Kocagoz SB, Underwood RJ, MacDonald DW, Gilbert JL, Kurtz SM. Ceramic heads decrease metal release caused by head-taper fretting and corrosion. Clin Orthop Relat Res. 2016;474(4):985-994. doi:10.1007/s11999-015-4683-1.
14. Asif I M. Characterisation and Biological Impact of Wear Particles from Composite Ceramic Hip Replacements. [PhD thesis]. Leeds, UK: University of Leeds; 2018. etheses.whiterose.ac.uk/20563. Accessed March 6, 2020.
15. Wight CM, Lanting B, Schemitsch EH. Evidence based recommendations for reducing head-neck taper connection fretting corrosion in hip replacement prostheses. Hip Int. 2017;27(6):523-531. doi:10.5301/hipint.5000545.
16. Lenguerrand E, Whitehouse MR, Beswick AD, et al. Risk factors associated with revision for prosthetic joint infection after hip replacement: a prospective observational cohort study. Lancet Infect Dis. 2018;18(9):1004-1014. doi:10.1016/S1473-3099(18)30755-2.
17. Al-Hajjar M, Fisher J, Hardaker C, Kurring G, Thompson J, Williams S. Wear of Large Diameter Ceramic-on-Ceramic Bearings in Total Hip Replacements under Edge Loading Conditions. Paper presented at: 60th Anniversary Meeting of Orthopaedic Research Society (ORS); March 15 March 18, 2014 2014 to Mar; New Orleans, LA, USA Abstract 1818.
18. Hernigou P, Homma Y, Pidet O, Guissou I, Hernigou J. Ceramic-on-ceramic bearing decreases the cumulative long-term risk of dislocation. Clin Orthop Relat Res. 2013;471(12):3875-3882. doi:10.1007/s11999-013-2857-2.
19. Ghasemi-Mobarakeh L, Kolahreez D, Ramakrishna S, Williams D. Key terminology in biomaterials and biocompatibility. Curr Opin Biomed Eng. 2019;10:45-50. doi:10.1016/j.cobme.2019.02.004.
20. National Joint Registry for England, Wales. Northern Ireland and the Isle of Man, 15th Annual Report 2018. Surgical data to 31 December 2017.ISSN 2054-1821 (Print) 2018:50 (table 3.7).
21. Peters RM, Van Steenbergen LN, Stevens M, Rijk PC, Bulstra SK, Zijlstra WP. The effect of bearing type on the outcome of total hip arthroplasty. Acta Orthopaedica. 2018,89(2):163-169. doi:10.1080/17453674.2017.1405669.
22. Report of R.I.P.O. Regional Register of Orthopaedic Prosthetic Implantology Overall Data Hip, Knee and Shoulder Arthroplasty in Emilia-Romagna Region (Italy) 2000-2016. 2018:57.
23. Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2018 Annual Report. Data period 1 September 1999 – 31 December 2017. Adelaide: AOA, 2018:157 (table HT30).
24. Sharplin P, Wyatt MC, Rothwell A, Frampton C, Hooper G. Which is the best bearing surface for primary total hip replacement? A New Zealand Joint Registry study. Hip Int. 2017;28(4):352-362. doi:10.5301/hipint.5000585.