Does navigated patellar resurfacing in total knee arthroplasty result in proper bone cut, motion and clinical outcomes?

Claudio Belvedere, Andrea Ensini, Silvia Tamarri, Michele d'Amato, Paolo Barbadoro, Alessandro Feliciangeli, Anish Rao, Alberto Leardini

Research output: Contribution to journalArticle


BACKGROUND: In total knee arthroplasty with patellar resurfacing, patellar bone preparation, component positioning and motion assessments are still not navigated. Only femoral/tibial component positioning is supported by computer-assistance. The aim of this study was to verify, in-vivo, whether knee surgical navigation extended to patellar resurfacing, by original instrumentation and procedures for patellar-based tracking, could achieve accurate patella preparation in terms of original thickness restoration, bone cut orientation, and normal knee motion.

METHODS: An additional navigation system for patellar data acquisition was used together with a standard navigation system for total knee arthroplasty in 20 patients. This supported the surgeon for patellar resurfacing via measurement of removed bone thickness, three-dimensional patellar cut orientations, and patello-femoral motion. Radiological and clinical examinations at 6 and 24-month follow-up were also performed.

FINDINGS: The medio-lateral patellar-bone cut orientation was respectively 0.5° (standard deviation: 3.0°) and 1.4° (1.7°) lateral tilt, as measured via navigation and post-operatively on the Merchant x-ray view. The cranio-caudal orientation was 3.8° (7.2°) of flexion. The thickness variation between patellar pre- and post-implantation was 0.2 (1.3) mm. Immediately after implantation, patello-femoral as well as tibio-femoral kinematics was within the normality. Good radiological and clinical examinations at 6 and 24-month follow-up were also observed.

INTERPRETATION: For the first time, the effect of patellar navigation for its resurfacing was assessed in-vivo during surgery, with very good results for thickness restoration, proper cut orientation, and normal knee motion. These results support the introduction of patella-related navigation-based surgical procedures for computer-assisted total knee arthroplasty.

Original languageEnglish
Pages (from-to)168-177
Number of pages10
JournalClinical Biomechanics
Early online dateJul 24 2019
Publication statusPublished - Oct 2019



  • Computer-assisted surgery
  • Patellar resurfacing
  • Patello-femoral kinematics
  • Surgical navigation
  • Tibio-femoral kinematics
  • otal knee arthroplasty

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