G5 Doctoral dissertation (article)
Biomechanical recovery factors in non-surgically treated ruptured achilles tendons (2023)
Biomekaaniset toipumistekijät ei-operatiivisesti hoidetuissa akillesjännerepeämissä

Khair, R. M. (2023). Biomechanical recovery factors in non-surgically treated ruptured achilles tendons [Doctoral dissertation]. University of Jyväskylä. JYU dissertations, 678. http://urn.fi/URN:ISBN:978-951-39-9693-2

JYU authors or editors

Publication details

All authors or editors: Khair, Ra’ad M.

eISBN: 978-951-39-9693-2

Journal or series: JYU dissertations

eISSN: 2489-9003

Publication year: 2023

Number in series: 678

Number of pages in the book: 1 verkkoaineisto (100 sivua, 23 sivua useina numerointijaksoina, 39 numeroimatonta sivua)

Publisher: University of Jyväskylä

Publication country: Finland

Publication language: English

Persistent website address: http://urn.fi/URN:ISBN:978-951-39-9693-2

Publication open access: Openly available

Publication channel open access: Open Access channel

Abstract

Achilles tendon rupture (ATR) is a frequent and disabling injury. In the last decade the incidence of ATR has been increasing especially in middle aged men participating in recreational sports. Plantar flexion strength decrements and endurance impairments are observed in patients with ATR whether treated surgically or non-surgically. Factors associated with good recovery are yet to be determined, particularly in non-surgically treated patients. Therefore, the aim of this thesis was to examine Achilles tendon (AT) and triceps surae (TS) muscle-tendon unit biomechanics in non-surgically treated patients 1-year after ATR. The results show that after rupture, non-surgically treated tendons heal to an elongated length, accompanied by remodeling of the TS muscles to shorter fascicles, and a reduced muscle cross-sectional area. However, stiffness in the injured AT was not different compared to the contralateral limb 1-year after rupture, in contrast with previous studies done on surgically treated tendons around the same time point. The relative contribution of flexor hallucis longus (FHL) during submaximal plantarflexion was higher in the injured limb, and this appeared to compensate for the decreased medial gastrocnemius activity. The lengthening of the injured tendon was associated with greater relative FHL activity, lower stiffness, and worse patient-reported outcomes. It seems that the increased length of the tendon after rupture is responsible for the observed ob-jectively measured and self-reported functional deficits. Non-surgical treatment after ATR seems to allow the conservation of the displacement pattern in the ruptured tendon, suggesting that non-surgical treatment may preserve normal subtendon organization. However, displacement amplitude and non-uniformity were altered after rupture. Using selective electrical stimulation to scan for the representative areas of the TS subtendons within the cross section of the AT, the data indicates that lateral gastrocnemius subtendon was located in the most anterior region adjacent to medial gastrocnemius both in the healthy and ruptured, non-surgically treated tendon. The novel method devel-oped in this thesis enables individual assessment of the TS subtendon organi-zation within the AT and may enable patient-specific rehabilitation protocols in the future.

Keywords: injuries and disabilities; sports injuries; calcaneal tendon; biomechanics; conservative treatment; surgical treatment; ultrasonography; rehabilitation; functional capacity; stiffness; doctoral dissertations

Free keywords: Achilles tendon; rupture; Flexor hallucis longus; non uniformity; stiffness; ultrasonography

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Ministry reporting: Yes

VIRTA submission year: 2023