Fixation and Bearings in Hip Replacement

In 2020, 23.0% of total hip replacement (THR) procedures in England, Wales, Northern Ireland, the Isle of Man and the States of Guernsey were performed and classified in the registry as cemented fixation, 35.8% as uncemented and 39% as hybrid fixation.¹

There is a continuing trend in favor of uncemented fixation in Australia, making up for 60.8% in 2020 vs. 51.3% in 2003. The percentage of hybrid fixation rose slightly from 34.8% in 2003 to 36.8% in 2020, while the numbers for cemented fixation decreased significantly, from 13.9% in 2003 to 2.4% in 2020.²

In Germany, considering the procedures recorded into registry dataset with the type of fixation, uncemented fixation remains the clear favorite despite a slight reduction from 78.6% in 2019 to 77.9% in 2020. Hybrid fixation increased from 15.2% in 2019 to 16.8% in 2020.³

In the United States, uncemented femoral stem fixation remains clearly the preferred option. In 2020, it was used in 94.2% of the procedures.⁴

The usage of cemented hip replacement has fallen to 5.3% in 2020. There is an increasing trend toward hybrid fixation, while uncemented is still the most popular procedure.⁵

In 2020, the most common head size as recorded by the NJR was 32mm, followed by 36mm and 28mm. There is a decline of the usage in 28mm heads and smaller accross all fixations. CoP with 32mm and 36mm is showing increased usage over the years.¹

The Australian registry distinctly looks at the usage of “mixed ceramic” components like BIOLOX®delta in THR. 36-38mm mixed ceramic/mixed ceramic bearings accounted for 73.8% of all primary THR procedures with this bearing surface in patients diagnosed for osteoarthritis in the period 2003-2020.²

In Germany, the most common head size was 32mm in 2020. It was used in 52.7% of all primary THRs. However, an increase in the numbers for 36mm femoral heads can be observed over the years. They are used in 41.4% of the cases vs. 33% in 2015. 28mm heads account for 5.0% of all primary THR.³

The share of 36mm heads in primary elective THR grew from 49% in 2012 to 59% in 2020. The usage of 32mm heads decreased slightly from 20.2% in 2019 to 18.7% in 2020. The treatments with head sizes larger than 40mm grew slowly from 5.4% in 2013 to 7.7% in 2020.⁴

New Zealand shows a trend toward 36mm heads since 2017, with 32mm remaining the most often used head size.⁵

2020 was the tipping point for ceramic femoral heads according to the NJR: Their use reached 50%, up from 17.9% in 2004. Correspondingly, the use of metal femoral heads decreased from 82.1% in 2004 to 50% in 2020.¹

A steady increase in the use of ceramic heads can be observed since 2014. Consequently, a decrease in the usage of metal heads has been recorded by the registry in the same period.^2,7-12

In Germany, the trend toward ceramic femoral heads is still increasing. They were used in 92.5% of the procedures in 2020. Metal femoral heads are used meanwhile in "only" 7.5% in 2020. ^3,13-18

In the United States, the percentage of ceramic femoral heads in THR has continuously been rising from 40.4% in 2012 to 78.6% in 2020. Accordingly, AJRR reports a continuous decline of the usage of metal heads and explains this trend with the surgeons' concern about fretting corrosion.⁴

According to the NZJR Annual Report 2021, the use of ceramic femoral heads continuously increased since 2013. Their percentage surpassed that of the metal heads in 2017.⁵

The use of CoP bearings increased from 15.9% in 2012 to 44.2% in 2020 in England, Wales, Northern Ireland, the Isle of Man and the States of Guernsey. The use of MoP bearings has decreased from 81.5% in 2004 to 50% in 2020. CoC bearings were implanted in 5.8% of the procedures in 2020.¹

In Australia, almost the totality, 96.8%, of the bearings implanted in 2020 consisted of mixed ceramic- and metal-on-cross-linked polyethylene, and mixed ceramic-on-mixed ceramic. The latter is defined as "modern bearing surfaces" by the registry. The hard-on-soft bearings with a ceramic head account for approximately half of the bearing surfaces implanted. CoC with mixed ceramic consisted of 99.7% of all primary total conventional hip procedures. When polyethylene was used, in 97.3% of the procedures in 2020, was XLPE. The usage of metal heads and CoC is gradually decreasing.^2,7-12

In Germany, the use of CoP bearings continuously grew from 68.2% in 2014 to 84.3% in 2020. There was a corresponding decrease in the use of CoC bearings from 15.7% to 8.4% and for MoP bearings from 16.1% to 7.3%.^3,13-18

Between 2012 and 2020 the share of CoP bearings doubled to 79.6% in the USA. In the same period MoP dropped down from 61.4% to 20.4%.⁴

In New Zealand, the CoP bearing surface continues to increase from 42% of the total in 2017 to 54% in 2020.⁵

Before 2013, dual mobility was scarcely used. An increase from less than 0.1% in 2004 to 2.2% of all primary THR in 2020 can be observed, of which nearly one-third is performed with a ceramic head (CoPoM: 28.6%, MoPoM: 71.4%). Dual mobility bearings are mostly used in cases of fractured femoral neck, accounting for 8.4% of these cases in 2020.¹

In Australia, the annual use of dual mobility constructs is increasing. Their use grew by 19.6% since 2019. Compared to other acetabular prostheses, dual mobility implants are used most frequently for fractured femoral neck, tumor and failed internal fixation.²

The German EPRD first included dual mobility bearings in the analysis of the Annual Report 2019. In 2020, this implant type accounted for 1.4% of all bearings in primary THA, whereas in acetabular revision a dual mobility cup was chosen in 29.3 % of cases.^3,17,18

In the United States, the use of dual mobility in both primary and revision hip replacement has continued to increase and accounted for 10.5% of all bearings used in elective primary surgeries in 2020, up from 5.32% in 2012. Dual mobility was used in over 25% of all revision procedures in 2020. This type of construct is used in all patient age groups: 9.4% of the patients under 50 years received a dual mobility bearing.⁴