title: Increased unilateral tendon stiffness and its effect on gait 2-6 years after Achilles tendon rupture.
abstract: Achilles tendon rupture (ATR) alters tissue composition, which may affect long-term tendon mechanics and ankle function during movement. However, a relationship between Achilles tendon (AT) properties and ankle joint function during gait remains unclear. The primary hypotheses were that (a) post-ATR tendon stiffness and length differ from the noninjured contralateral side and that (b) intra-patient asymmetries in AT properties correlate to ankle function asymmetries during gait, determined by ankle angles and moments. Ultrasonography and dynamometry were used to assess AT tendon stiffness, strain, elongation, and rest length in both limbs of 20 ATR patients 2-6 years after repair. Three-dimensional ankle angles and moments were determined using gait analysis. Injured tendons exhibited increased stiffness, rest length, and altered kinematics, with higher dorsiflexion and eversion, and lower plantarflexion and inversion. Intra-patient tendon stiffness and tendon length ratios were negatively correlated to intra-patient ratios of the maximum plantarflexion moment and maximum dorsiflexion angle, respectively. These results suggest that after surgical ATR repair, higher AT stiffness, but not a longer AT, may contribute to deficits in plantarflexion moment generation. These data further support the claim that post-ATR tendon regeneration results in the production of a tissue that is functionally different than noninjured tendon.
authors.affiliation: Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: A N
authors.initials: AN
authors.lastname: Agres
authors.affiliation: Julius Wolff Institute, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: G N
authors.initials: GN
authors.lastname: Duda
authors.affiliation: Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: T J
authors.initials: TJ
authors.lastname: Gehlen
authors.affiliation: Department of Training and Movement Science, Humboldt University of Berlin, Berlin, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Arampatzis
authors.affiliation: Institute for Biomechanics, ETH Zurich, Zürich, Switzerland.
authors.forename: W R
authors.initials: WR
authors.lastname: Taylor
authors.affiliation: Center for Musculoskeletal Surgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Manegold
mesh_terms: D000125:Achilles Tendon / Q000000981:diagnostic imaging / Q000293:injuries* / Q000503:physiopathology*; D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D004548:Elasticity; D054459:Elasticity Imaging Techniques; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012421:Rupture / Q000000981:diagnostic imaging / Q000503:physiopathology; D013997:Time Factors
keywords: Tendon regeneration; gait analysis; muscle-tendon unit; tendon adaptation; tendon healing