HSS Journal

, Volume 6, Issue 2, pp 134–137

Failure of the Patellar Tendon with the Patella Everted versus Noneverted in a Matched-Pair Cadaver Model


  • James A. Ryan
    • Department of Orthopaedic SurgeryHospital for Special Surgery
  • Kathleen N. Meyers
    • Department of BiomechanicsHospital for Special Surgery
  • Paolo DiBenedetto
    • Clinic of Orthopaedics and TraumatologyUniversity of Udine, AOU of Udine
  • Timothy M. Wright
    • Department of BiomechanicsHospital for Special Surgery
    • Department of Orthopaedic SurgeryHospital for Special Surgery
Original Article

DOI: 10.1007/s11420-009-9149-0

Cite this article as:
Ryan, J.A., Meyers, K.N., DiBenedetto, P. et al. HSS Jrnl (2010) 6: 134. doi:10.1007/s11420-009-9149-0


Avoidance of patellar eversion during total knee arthroplasty may help to prevent injury to the patellar tendon. The purpose of this study was to compare the load-to-failure of the everted versus the noneverted patella in a cadaveric model. Fourteen cadaver knees (seven pairs) were loaded to failure with the patella everted in one knee and not everted in the other. Mean load-at-ultimate failure in the patella-everted group was 1,111 ± 572 N, and in the patella-noneverted group was 1,621 ± 683 N (p = 0.01). Additionally, loads-at-initial-partial failure were lower (p = 0.04) in the patella-everted compared to the patella-noneverted group, 573 ± 302 N versus 1,115 ± 358 N, respectively. A partial failure of the patellar tendon occurred in 100% of the everted specimens, whereas only 57% of the noneverted specimens had partial failure. These findings suggest patella eversion may lead to failure of the patellar insertion at lower loads than when the patella is not everted.


patellar eversionknee arthroplastypatellar tendonfailure

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© Hospital for Special Surgery 2010