Correspondence of high-frequency ultrasound and histomorphometry of healing rabbit Achilles tendon tissue

Abstract

These findings add new in-depth structural knowledge to the established non-invasive analytical tool, ultrasound.

Bioactive, Elastic, and Biodegradable Emulsion Electrospun DegraPol Tube Delivering PDGF‐BB for Tendon Rupture Repair

“…Another reason can be the protein presence (in aqueous droplets) within the fibers, thus resulting in internal structural defects. [20b] Failure stresses of healthy rabbit Achilles tendons which are similar in strength as human flexor tendons have UTS in the range of 30 MPa . The UTS of the electrospun DP scaffolds (1–2 MPa) are too low to act as reinforcement of the structural tendons which are not intended when applied in tendon repair in a clinical setting.…”

“…An electrospun tube made from newly synthesized type of DP, which is softer and more elastic, surgeon friendly, and better suited for tendon rupture repair, compared to the already established classic DP has been applied over the wound site after conventional tendon repair. It has been shown not to evoke an adverse cellular response and to significantly minimize peritendinous adhesion formation in a rabbit model . Using this newly synthesized DP for production of reversibly expandable electrospun scaffolds/tubes offers a big advantage over other electrospun polymers like poly(lactide‐co‐glycolic acid) (PLGA) or poly(caprolactone) (PCL), that exhibit considerably low strain at break…”

Rabbit Achilles tendon full transection model – wound healing, adhesion formation and biomechanics at 3, 6 and 12 weeks post-surgery

“…Also in our research group, the fully transected and sutured rabbit Achilles tendon model has been successfully used to study the cellular response towards a newly synthesized electrospun polymer tube that was placed around a conventionally sutured tendon to act as a physical anti-adhesion barrier ( Buschmann et al, 2015 ). Furthermore, the rabbit Achilles full transection model can also be used in non-invasive longitudinal ultrasound studies, with Power Doppler assessments elucidating hematomas or increased vascularization at the repair site, and gray scale variation corresponding to histological changes on the collagen and cell level over time ( Buschmann et al, 2014 ). In addition, although the Achilles tendon is not an intrasynovial tendon, adhesion formation to the surroundings (especially to the peritenon) can also be fairly studied in this model by histology ( Tan et al, 2010 ), which has been successfully used to compare a conventionally 4-strand Becker sutured tendon with a physical barrier-bearing test group ( Meier Buergisser et al, 2014 ).…”

“…Because of these two characteristics, the rabbit AT has been used in our group to study the effect of a synthetic polymer carrier device that was placed around the fully transected AT after conventional suture by evaluation of the cellular response towards the implant ( Buschmann et al, 2013a , b ). Furthermore, the rabbit AT is large enough to examine accurately morphological as well as cell-based tissue changes with non-invasive ultrasound ( Buschmann et al, 2014 ), which might be limited in smaller animal models in terms of specimen size.…”

Tissue Regeneration

“…Starting with the smallest molecular entity, tropocollagen molecules assemble to form microfibrils. Covalently connected, these microfibrils form sub-fibrils and fibrils of the collagen which is typically seen in histological sections of tendon tissue as slightly waved "crimps" [15,16]. Fibrils form bundles resulting in fascicles.…”