TY  - JOUR
A1  - Stäudle, Benjamin
A1  - Seynnes, Olivier
A1  - Laps, Guido
A1  - Göll, Fabian
A1  - Brüggemann, Gert-Peter
A1  - Albracht, Kirsten
T1  - Recovery from achilles tendon repair: a combination of Postsurgery Outcomes and Insufficient remodeling of muscle and tendon
JF  - Medicine & Science in Sports & Exercise
N2  - Achilles tendon rupture (ATR) patients have persistent functional deficits in the triceps surae muscle–tendon unit (MTU). The complex remodeling of the MTU accompanying these deficits remains poorly understood. The purpose of the present study was to associate in vivo and in silico data to investigate the relations between changes inMTU properties and strength deficits inATR patients. Methods: Elevenmale subjects who had undergone surgical repair of complete unilateral ATR were examined 4.6 ± 2.0 (mean ± SD) yr after rupture. Gastrocnemius medialis (GM) tendon stiffness, morphology, and muscle architecture were determined using ultrasonography. The force–length relation of the plantar flexor muscles was assessed at five ankle joint angles. In addition, simulations (OpenSim) of the GM MTU force–length properties were performed with various iterations of MTU properties found between the unaffected and the affected side. Results: The affected side of the patients displayed a longer, larger, and stiffer GM tendon (13% ± 10%, 105% ± 28%, and 54% ± 24%, respectively) compared with the unaffected side. The GM muscle fascicles of the affected side were shorter (32% ± 12%) and with greater pennation angles (31% ± 26%). A mean deficit in plantarflexion moment of 31% ± 10% was measured. Simulations indicate that pairing an intact muscle with a longer tendon shifts the optimal angular range of peak force outside physiological angular ranges, whereas the shorter muscle fascicles and tendon stiffening seen in the affected side decrease this shift, albeit incompletely. Conclusions: These results suggest that the substantial changes in MTU properties found in ATR patients may partly result from compensatory remodeling, although this process appears insufficient to fully restore muscle function.
KW  - Tendon Rupture
KW  - Stiffness
KW  - Simulation
KW  - Muscle Force
KW  - Muscle Fascicle
Y1  - 2021
U6  - http://dx.doi.org/10.1249/MSS.0000000000002592
SN  - 1530-0315
VL  - 53
IS  - 7
SP  - 1356
EP  - 1366
PB  - American College of Sports Medicine
CY  - Philadelphia, Pa.
ER  -