New dynamic suture material for tendon transfer surgeries in the upper extremity - a biomechanical comparative analysis

Tatjana Pastor; Ivan Zderic; Mehar Dhillon; Boyko Gueorguiev; R Geoff Richards; Torsten Pastor; Esther Vögelin

doi:10.1007/s00402-024-05322-5

New dynamic suture material for tendon transfer surgeries in the upper extremity - a biomechanical comparative analysis

Arch Orthop Trauma Surg. 2024 May 2. doi: 10.1007/s00402-024-05322-5. Online ahead of print.

Authors

Tatjana Pastor^{1

2}, Ivan Zderic³, Mehar Dhillon³, Boyko Gueorguiev³, R Geoff Richards³, Torsten Pastor⁴, Esther Vögelin⁵

Affiliations

¹ AO Research Institute Davos, Davos, 7270, Switzerland. Tatjana.pastor@spital.so.ch.
² Department for Plastic and Hand Surgery, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland. Tatjana.pastor@spital.so.ch.
³ AO Research Institute Davos, Davos, 7270, Switzerland.
⁴ Department of Orthopaedic and Trauma Surgery, Lucerne Cantonal Hospital, Lucerne, Switzerland.
⁵ Department for Plastic and Hand Surgery, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.

PMID: 38693291
DOI: 10.1007/s00402-024-05322-5

Abstract

Background: Early mobilization after tendon surgery is crucial to avoid commonly observed postoperative soft tissue adhesions. Recently, a new suture was introduced (DYNACORD; DC) with a salt-infused silicone core designed to minimize laxity and preserve consistent tissue approximation in order to avoid gap formation and allow early mobilization.

Aims: To compare the biomechanical competence of DC against a conventional high strength suture (FiberWire; FW) in a human cadaveric tendon transfer model with an early rehabilitation protocol.

Methods: Sixteen tendon transfers (flexor digitorum superficialis (FDS) IV to flexor pollicis longus (FPL)) were performed in 8 pairs human cadaveric forearms using either DC or FW. Markings were set 0.8 cm proximally and 0.7 cm distally to the level of the interweaving zone of the transfer. All specimens underwent repetitive thumb flexion against resistance in 9 intermittent series of 300 cycles each, simulating an aggressive postoperative rehabilitation protocol. After each series, the distance of the proximal marker to the interweaving zone (proximal), the length of the interweaving zone (intermediate) and the distance of the distal marker to the interweaving zone (distal) were measured.

Results: Pooled data over all nine series, normalized to the immediate postoperative status, demonstrated no significant differences between FW and DC (p ≥ 0.355) for the proximal and distal markers. However, at the intermediate zone, DC was associated with significant length shortening (p < 0.001) compared to FW without significant length changes (p = 0.351). Load to catastrophic failure demonstrated significant higher forces in FW (p = 0.011). Nevertheless, due to failure mainly proximal or distal of the transfer zone, these loads are not informative.

Conclusion: From a biomechanical perspective, DC preserved tissue approximation and might be considered as a valid alternative to conventional high-strength sutures in tendon transfer surgery. DC might allow for a shorter interweaving zone and a more aggressive early postoperative rehabilitation program, possibly avoiding commonly observed postoperative soft tissue adhesions and stiffness.

Keywords: Biomechanics; Dynacord; Early rehabilitation; FiberWire; Tendon approximation; Tendon transfer.