Patient reported outcomes and implant survivorship after Total knee arthroplasty with the persona knee implant system: two year follow up

Background

More personalized implant designs for total knee arthroplasty might optimize the clinical outcome after surgery. One of these personalized implant designs is the Persona knee implant system (Zimmer Biomet, Warsaw, Indiana, USA). The primary objective of this study was to determine patient reported outcomes and implant survivorship of the Persona Knee system used in primary total knee arthroplasty, up to two years after surgery.

Methods

From November 2013 to July 2016 consecutive patients undergoing primary total knee arthroplasty were enrolled in a prospective observational cohort study at three centers. Preoperatively, at 6 weeks, 6 months, 1 and 2 years after surgery, patients completed the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford Knee Score (OKS), the Knee Society Score (KSS, 2011, modified version) and the EQ-5D. Adverse Events were captured, assessed for relationship to device, and recorded in the study database. Furthermore, physical functioning was assessed by the orthopedic surgeon.

Repeated measures analyses were performed on PROM scores. Kaplan Meier was used to calculate survivorship of the Persona Knee Implant System.

Results

A total of 146 total knee arthroplasties were performed. 61% (89/146) of the patients were female and mean age was 64.7 (± 6.9) years. Two years after surgery, one patient had a revision of the polyethylene insert because of a periprosthetic joint infection. Therefore, the Kaplan-Meier survival estimate at 2 years was 0.99 (0.95–1.00 95% CI).

OKS increased from 22.1 (95% CI 20.9–23.3) to 41.8 (95% CI 40.6–43.1) two years after surgery. Furthermore, all other PROMs also increased from before surgery to 2 year postoperatively.

Conclusion

The Persona Knee implant is safe and effective and the clinical results up to two years after surgery are promising. PROMs results are very good; pain, function and quality of life all improved greatly after TKA. Further studies are needed to determine the long term clinical performance of the Persona prosthesis.

Trial registration

Clinicaltrials.gov (NCT02337244). Registered June 1st, 2015. Retrospectively registered.