Issue: December 2019
December 03, 2019
4 min read

Diversity in primary THA showcases main theme of the EFORT 2020 Congress

Issue: December 2019
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For every EFORT Congress, a specific main theme aligned with the EFORT mission of improving patient care is selected to drive all discussions and exchanges onsite. In this context, for the upcoming EFORT Congress 2020 in Vienna, Austria, EFORT is actively promoting both harmonization and diversity principles within the orthopaedics and traumatology community.

Whereas harmonization is essential for treatment agreement at all levels of the medical practice, diversity implies the same amount of evidence will not necessarily engender the same guideline. This last statement corresponds to the definition of evidence-based medicine (EBM), as described by Professor David Sackett in the early 1990s.

The upcoming Vienna 2020 main theme EBM session led by Prof. Johan Karrhölm, from Sahlgrenska University Hospital in Sweden, will highlight how, through the choice of bearings, diversity applies to one of the most commonly performed surgical procedures worldwide: hip arthroplasty. Indeed, as hundreds of implant configurations are available for orthopaedic practice, different options in the choice of femoral head size, the joint surface material and even in the fixation method can be envisioned. For clinically well-proven implants, the surgeon might seek specific properties to address expected patient-specific problems, such as poor bone quality or high risk of dislocation. Moreover, several additional factors, like the type of prosthesis, the use of cement and the antibiotic prophylaxis needed, influence the survival of implants, and thus the initial choice of the surgeon.

Global Diversity in Bearing in Primary THA
Evidence Based Medicine Session

Wednesday 10 June 2020; 17:00-18:30 | auditorium Copenhagen
Orthopaedics - Pelvis, Hip & Femur
Moderation: Johan Kärrholm (Sweden)

  • Which is the Optimal Head Size? – Georgios Tsikandylakis (Sweden)
  • Which Articulating Design to Use: Cup With or Without Inbuilt Dislocation Protection? – Søren Overgaard (Denmark)
  • Which are the Optimal Articulation Materials? – Luigi Zagra (Italy)

Despite extensive preclinical testing and CE certification marking, all new hip implants should be presumed to be associated with unknown and potentially adverse effects until otherwise proven in well-performed clinical studies. Often, when selecting among several types of hip implants, there is a trade-off between the implant specific factors — such as reduced dislocation — and common late complications, like loosening or wear. As choice of bearing material and articulation design in THA will influence the amount of wear, range of motion and joint stability, these properties will affect the risk of complications and the revision rate from the short- and long-term standpoint.

Sir John Charnley introduced small-diameter femoral heads to reduce friction and wear, whereas bigger heads were favored by others to maximize stability. In 1990, Livermore and colleagues suggested a compromise that corresponded to a 28-mm head, which, for at least a decade, became a standard in most countries. Introduction of metal-metal articulations and, above all, highly crosslinked polyethylene opened up the possibility for the use of bigger head sizes, but recent studies have suggested limited clinical benefits when head sizes greater than 32 mm are used, and even adverse effects if big metallic heads are used. Lipped, inclined and constrained liners and dual-mobility (DM) cups have been available for decades to improve stability of artificial hip joints. Numerous studies have documented these can reduce the risk of dislocation, whereas other studies have failed to do so. Some have reported an increase in adverse effects caused by impingement, loosening, wear and complications, such as intraprosthetic dislocation. Today, in many countries, there is, however, an increased interest in and greater use of DM cups to address the dislocation problem.


Highly crosslinked polyethylene liners or cups articulating against metallic or ceramic heads or ceramic-ceramic articulations are today the most commonly used hip articulation material, but there is presently no consensus concerning the most optimal combination of materials. Thus, despite decades of evolution, there are still uncertainties concerning the best articulation to use, partially because the choice depends on various patient-related factors (demographic components, comorbidities, age and activity levels), as well as on the surgeon’s experience and a compromise between the costs and expected time in situ.

When treating a patient, the main goal of any orthopaedics and traumatology (O&T) practitioner is to find the best solution to improve the quality of the patient’s life while entirely fulfilling the patient’s expectations. In the case of primary total hip arthroplasty, THA surgeons aim at the longest survival for the “new hip.” With the exponential increase in innovations within the O&T specialty and the constant availability of new materials, THA outcomes were expected to be positively influenced. However, compared to implants already in use, most THA prostheses introduced to the market in the past 2 decades have been shown to lead to similar or even worse results. In Sweden, during the last 3 years, the frequency of reoperations (not only revision surgery, but all types of hip-related surgical procedures) was reported to be 2.2% within 2 years after a primary THA. In general, new technologies with proven clinical value have gained in popularity, but it remains difficult to prove that new types of implants globally influence well-established procedures. Navigation, robotic assistance and patient-specific instruments have been shown to reduce the variability of implant positioning, but their cost-effectiveness still needs to be more firmly proven.

The panel of speakers appointed for this main theme session will, therefore, present information about head size, articulation design and material diversity in primary THA with an emphasis on the use of evidence from well-designed and well-conducted research, to address the most common aspects faced by arthroplasty surgeons to optimize decision-making.

Vienna banner

The EBM session entitled, “Global Diversity in Bearing in Primary THA,” is part of the core scientific program of the EFORT Annual Congress and is open to fully registered attendees. All details to sign-up are available at the congress registration platform. Visit the 2020 congress website to learn more.