Polycaprolactone/ultra-high molecular weight polyethylene partially absorbable suture with improved mechanical performances for tendon and ligament repair

Abstract

Orthopedic suture, as an implantable surgical device for skeletal and soft tissue connection, is vital in tendon or ligament injury repair. Resorbable therapy approaches exhibit excellent biocompatibility in the field of suture materials but lack a long-term fixation effect in orthopedic treatment. Herein, this study focused on a series of partially absorbable orthopedic sutures, which were composed of absorbable polycaprolactone (PCL) multifilament and non-absorbable ultra-high molecular weight polyethylene (UHMWPE) multifilament. Comprehensive in vitro mechanical evaluations were conducted to probe the relationship between material composition and mechanical properties of the sutures. The results showed that the partially absorbable sutures, especially P/U = 50/50 and P/U = 25/75, exhibited significant improvements in mechanical properties compared to single-material sutures. The tensile strength of P/U = 50/50 and P/U = 25/75 was 180.99 and 210.91 N, respectively, which was about two times higher than that of absorbable PCL suture P/U = 100/0 (62.42 N). Furthermore, their suture-to-suture friction force was 1.89 times and 2.51 times that of non-absorbable UHMWPE suture P/U = 0/100, respectively, which guaranteed good knot security. Compared with the clinically used orthopedic suture Ethibond (110 N), P/U = 50/50 and P/U = 25/75 also presented superior tensile properties. Notably, P/U = 50/50 and P/U = 25/75 had similar tensile curves to that of the native tendon/ligament, which might be beneficial to tissue healing. Moreover, the R2 of Eyring's model to simulate the creep curves of each suture was higher than 0.99, which indicated that Eyring's model could be used in predicting the long-term creep behavior of the sutures.

Hybrid structures for Achilles' tendon repair

“…The obtained results constitute a beneficial creep behavior taking into account the desired application of the presented medical device, which should endure load application over extended time without becoming lax. The creep deformation of a structure will result in gap formation or even failure of the repair, so by minimizing elongation, it is possible to reduce gap formation and increase the repair of the tissue 59 …”

“…The creep deformation of a structure will result in gap formation or even failure of the repair, so by minimizing elongation, it is possible to reduce gap formation and increase the repair of the tissue. 59 There are a few examples of commercialized fibrous devices made of PET (e.g., Leeds-Keio Ligament and Lars Ligament) with adequate initial mechanical strength. However, it is reported that these nondegradable devices generally fail due to the long-term mechanical phenomena such as creep, fatigue, stress shielding, and permanent deformation.…”

Functional Ultra-High Molecular Weight Polyethylene Composites for Ligament Reconstructions and Their Targeted Applications in the Restoration of the Anterior Cruciate Ligament

“…Zhang et al [ 190 ] reported that UHMWPE filament could be modified with polycaprolactone for ligament and tendon regeneration [ 191 ]. Absorbable polycaprolactone PCL has attracted mainstream attention in recent years for the development of tendon/ligament repair materials due to its excellent performance attributes of low degradation, high stability, non-toxicity, and bioresorbability [ 192 ].…”

Biofunctionalization of UHMWPE Polymer and Its Application in Anterior Cruciate Ligament Reconstruction

“…Absorbable polycaprolactone PCL has attracted mainstream attention in recent years for the development of tendon/ligament repair materials due to its excellent performance of degradation, high stability, non-toxicity, and bioresorbability [138]. Fibrous PCL has also been reported to be able to help cell growth [139]. C.C Schmidt et al reported that growth factors play an essential role in the stimulation of fibroblast division and ligament healing.…”