Multi-Axis Fatigue Experimentation System of Intramedullary Implants for Femur and Tibia

Mikko Kanerva, Tuomas Pärnänen, Jarno Jokinen, Juha Haaja, Antti Ritvanen, Dietrich Schlenzka

Research output: Contribution to journalArticleScientificpeer-review

1 Citation (Scopus)
11 Downloads (Pure)


Current designs of leg-lengthening implants have faced serious failures due to inadequacies in the mechanical design. The failure typically is the result of fatigue induced by a combined loading condition with axial and shear components acting in the tubular body of the implant. One of the reasons leading to the failure is improper verification testing for the design of the fatigue limit. The current test standards for pre-clinical design phases of nail implants are relatively straightforward and widely accepted yet cannot produce the three-dimensional stress state representative of the anticipated operation in a patient during the consolidation phase. This work introduces a major improvement toward a method for verifying fatigue life of tubular as well as solid implants under combined torque, axial load, and bending. The report describes a new loading fixture, a calibration method, and compares the qualification results of finite element simulation analyses and experimental measurements during cyclic loading tests. The findings state that the fixture produces controlled multi-axial loadings to study varied osteotomy locations, quasi-static strength and fatigue of intramedullary implants at an intermediate, 2 Hz, cycle rate.

Original languageEnglish
Pages (from-to)984-995
Number of pages12
JournalJournal of Orthopaedic Research
Issue number5
Early online date2 Dec 2019
Publication statusPublished - 2020
Publication typeA1 Journal article-refereed


  • consolidation phase
  • fatigue
  • finite element analysis
  • implant
  • multi-axis loading

Publication forum classification

  • Publication forum level 2

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine


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