SEDL / STP / STP1525-EB / STP49273S

Relative Motion of ACL Insertion Points In Vivo: A Case Study, Including Skiing Maneuvers

Freudiger, Stefan
Ingenieurbüro Flugwesen und Biomechanik IFB AGBündackerstr. 67, Bremgarten,

Vogt, Wolfgang
Orthopädisches Fachzentrum OFZ, Garmisch-Partenkirchen,

Wirz, Dieter
Universität Basel, Basel,

Pages: 14    Published: Jan 2011

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Abstract

FASTRAK receivers were mounted on Kirschner-wires inserted in the distal femur and proximal tibia, respectively. Relative motions of the anterior cruciate ligament (ACL) insertion points were calculated for a hypothesised ACL while diagnostic and skiing load cases were applied to the knee. The highest strains, in descending order were: (i) Lachman test (13.5 %), (ii) 20 N•m internal rotation load (10.6 %) and (iii) latero-medial knee movement (6.4 %). The Lachman-procedure not only produces anterior tibial translation (5.5 mm) but as well internal rotation (10.0°). The medial knee movement produces valgus (2.3°) and external rotation (15.6°), but induces flexion (9.7°) as well, which therefore increases ACL load due to a non physiological instantaneous centre of rotation.