Health Policy & Economics
New Implant Introduction in Total Hip Arthroplasty Using Radiostereometric Analysis: A Cautionary Note

https://doi.org/10.1016/j.arth.2019.10.004Get rights and content

Abstract

Background

It has been proposed that the introduction of new hip implant technology in orthopedic surgery be conducted in a more controlled manner in order to properly ensure patient safety and the likelihood of favorable outcomes. This stepwise introduction would first require a prospective randomized study in a small cohort of patients, using radiostereometric analysis (RSA). The aim of this study is to determine if the recent literature supports the use of RSA as an early screening tool to accurately predict the long-term outcomes of cementless femoral stems.

Methods

A review of the recent published literature identified 11 studies that used RSA to predict the long-term stability of a cementless femoral component. These RSA predictive data were compared to the 10-year revision rate reported in the Australian Registry or in the published literature to determine its reliability.

Results

RSA data did not universally predict long-term stem fixation. In 2 of the 11 cases (18%), the RSA study incorrectly predicted the ability of the cementless stem to reliably osseointegrate. Of the 9 stems considered stable in the RSA studies, the 10 year registry and literature data confirmed that 6 implants had a low revision rate and were well performing. One stem has not performed well clinically and has been listed as having a higher than anticipated rate of revision in the registry. Two stems do not have sufficient follow-up. Of the 2 stems RSA predicted to do poorly, 1 is well performing at 10 years, and 1 has a high revision rate at 8 years.

Conclusion

In the stepwise introduction of new hip implants, RSA should be best considered as an adjunct tool in deciding whether or not an implant should be evaluated in a larger multicenter clinical studies, rather than the sole criterion.

Section snippets

Methods

We reviewed the published literature since November 2012 for studies using RSA in the assessment of cementless femoral components. The electronic databases PubMed, EMBASE, and Google Scholar were searched using the following key words: radiostereometric analysis; RSA; femoral stem; cementless; and arthroplasty. The search was completed in July 2018. RSA studies were included in this review if the study reported on a cementless stem that was not previously reported in the systematic review by de

Results

The 2-year distal migration was described for 10 of these stems from RSA studies (Cerafit, CFP, CUT, Fitmore, Furlong, M/L Taper, Nanos, Scyon, Synergy, and VerSys) (Table 1). Of these 10 prostheses, 1-year distal migration was presented for 8 stems (Cerafit, CFP, CUT, Fitmore, Furlong, Nanos, Scyon, and VerSys). No data concerning 1-year distal migration were available for M/L Taper and Synergy. Furthermore, no data concerning the distal migration was found for the Proxima stem. Rather, the

Discussion

This study looked at the correlation between femoral stem RSA data at 2 years, with long-term aseptic revision rates of cementless femoral stems. We found that the RSA data did not universally predict long-term stem fixation. In 2 of the 11 cases (18%), the RSA study incorrectly predicted the ability of the cementless stem to reliably osseointegrate. In 1 case, the RSA data incorrectly predicted that the implant would be unstable, and in the other case it incorrectly predicted that the stem

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    One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2019.10.004.

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