Elsevier

The Journal of Arthroplasty

Volume 35, Issue 10, October 2020, Pages 2872-2877
The Journal of Arthroplasty

Primary Knee
Similar Risk of Revision After Kinematically Aligned, Patient-Specific Instrumented Total Knee Arthroplasty, and All Other Total Knee Arthroplasty: Combined Results From the Australian and New Zealand Joint Replacement Registries

https://doi.org/10.1016/j.arth.2020.05.065Get rights and content

Abstract

Background

Kinematic alignment (KA) in total knee arthroplasty (TKA) replicates individual knee joint line orientation and physiological soft tissue balance. There are limited data on the effect of KA on survivorship compared with other methods of implanting a TKA. The aim of this study was to compare the survivorship of the same design of TKA implanted with either patient-specific instrument (PSI) KA or with computer-assisted surgery and conventionally instrumented.

Methods

We performed an observational study of data from 2 national joint registries on all patients who underwent a TKA with a Triathlon cruciate-retaining TKA (Stryker, Mahwah, NJ) from January 2011 to December 31, 2013. The outcomes of knees performed with unrestricted KA using patient-specific instrument were compared with computer-assisted surgery and conventionally instrumented Triathlon cruciate-retaining TKA. The principal outcome measure was time to first revision using Kaplan-Meier estimates of survivorship. Cox proportional hazard ratios, adjusted for age and gender, were used to compare the 2 groups.

Results

There were 20,512 TKA procedures recorded, of which 416 were performed using KA-PSI. The KA-PSI group was younger (66.8 ± 8.2 vs 68.3 ± 9.2, P = .001), with an identical gender distribution. The cumulative revision rate at 7 years was 3.1% for the KA-PSI Triathlon cohort and 3.0% for the other Triathlon TKA cohort (P = .89). The most common reasons for revision in the KA-PSI group were maltracking, patella erosion, and arthrofibrosis.

Conclusion

Kinematically aligned Triathlon TKA using PSI has similar revision rate as all other Triathlon TKA.

Section snippets

Material and Methods

Data were obtained from the Australian and New Zealand national joint replacement registries from January 1, 2011 to December 31, 2013. Inclusion criteria were primary TKAs performed for a diagnosis of osteoarthritis using the cruciate-retaining (CR) Triathlon Total Knee Replacement system (Stryker). TKAs performed using the OtisKnee (OtisMed)/ShapeMatch PSI (Stryker) were compared with all other Triathlon TKAs implanted using conventional or navigated instrumentation. The period was chosen as

Results

A total of 20,512 primary Triathlon CR TKAs were included. Of these, 416 cases were performed using KA-PSI. The gender distribution between the cohorts was identical (Table 1). Patients in the KA-PSI cohort were younger than in the other TKA cohort (mean age 66.8 ± standard deviation 8.2 vs 68.3 ± 9.2). PSI-KA TKA was implanted by 29 surgeons in 29 hospitals. Other TKAs were implanted by 507 surgeons in 243 hospitals. In the other TKA group, 48.6% were computer assisted, and 51.4% were

Discussion

In this combined national joint registry study, we found no difference in revision rates between kinematically aligned TKA performed using PSI compared with computer-assisted and conventionally instrumented TKA of the same implant. There was a difference in reasons for revision between the groups with the KA-PSI group predominantly being revised because of patellofemoral issues. Although many authors have expressed concern regarding the effect of KA alignment on implant survivorship, in this

Conclusions

This multinational registry analysis demonstrated similar midterm revision risk between KA-PSI Triathlon CR TKAs and all other Triathlon CR TKAs. These 2 groups should receive a long-term follow-up for further comparison.

Acknowledgments

The authors thank the AOANJRR and the hospitals, orthopedic surgeons, and patients whose data made this work possible. The Australian government funds the AOANJRR through the Department of Health and Aging.

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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.2020.05.065.

    The research has been performed at the North Shore Hospital and the Australian Orthopaedic Association National Joint Replacement Registry.

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