Effects of patellofemoral overstuffing on knee flexion and patellar kinematics following total knee arthroplasty: a cadaveric study

Daniel N. Bracey, Matthew L. Brown, Hoyt R. Beard, Sandeep Mannava, Omar Nazir, Thorsten M. Seyler, Jason E. Lang

Research output: Contribution to journalArticle

14 Scopus citations


Purpose: The purpose of this study was to test the hypothesis that overstuffing the patellofemoral joint during total knee arthroplasty (TKA) would decrease passive knee flexion and alter patellar kinematics during knee flexion. Methods: Ten cadaveric knees were implanted with cruciate-retaining TKAs, and the patellofemoral joint was overstuffed in 2-mm increments with custom-augmented patellar prostheses (+2 mm through +8 mm). Changes to knee flexion, patellar shift, tilt and rotation were measured with an imageless optical-tracking computer navigation system. Results: Knee flexion decreased an average 1.2° with each additional 2 mm of patellar thickness. Compared with control TKA (+0 mm), no significant decrease in knee flexion was detected until the patellofemoral joint was overstuffed with the +8-mm patellar prosthesis. Kinematic tracking data showed significantly greater lateral shift of patella with the +6- and +8-mm prostheses and significantly greater lateral tilt with the +8-mm prosthesis. Overstuffing had no appreciable effect on patellar rotation. Conclusions: Passive knee flexion after TKA is significantly reduced when overstuffing the patellofemoral joint by +8 mm, and patellofemoral kinematics are altered when overstuffing the joint by +6 mm. These results demonstrate the relatively modest effects of patellofemoral overstuffing on knee flexion and patellar tracking kinematics after TKA.

Original languageEnglish (US)
Pages (from-to)1715-1722
Number of pages8
JournalInternational Orthopaedics
Issue number9
Publication statusPublished - Oct 1 2015
Externally publishedYes



  • Computer navigation
  • Overstuffing
  • Patellar thickness
  • Patellofemoral joint
  • Patellofemoral kinematics
  • Total knee arthroplasty

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

Cite this