Tendon gradient mineralization for tendon to bone interface integration

Abstract

Tendon-to-bone integration is a great challenge for tendon or ligament reconstruction regardless of use of autograft or allograft tendons. We mineralized the tendon, thus transforming the tendon-to-bone into a “bone-to-bone” interface for healing. Sixty dog flexor digitorum profundus (FDP) tendons were divided randomly into 5 groups: 1) normal FDP tendon, 2) CaP (Non-extraction and mineralization without fetuin), 3) CaPEXT (Extraction by Na2HPO4 and mineralization without fetuin), 4) CaPFetuin (Non-extraction and mineralization with fetuin), and 5) CaPEXTFetuin (Extraction and mineralization with fetuin). The calcium and phosphate content significantly increased in tendons treated with combination of extraction and fetuin compared to the other treatments. Histology also revealed a dense mineral deposition throughout the tendon outer layers and penetrated into the tendon to a depth of 200 μm in a graded manner. Compressive moduli were significantly lower in the four mineralized groups compared with normal control group. No significant differences in maximum failure strength or stiffness were found in the suture pull-out test among all groups. Mineralization of tendon alters the interface from tendon to bone into mineralized tendon to bone, which may facilitate tendon-to-bone junction healing following tendon or ligament reconstruction.

Modifying the strength and strain concentration profile within collagen scaffolds using customizable arrays of poly-lactic acid fibers

“…Emerging efforts have begun to shift focus from homogenous biomaterials for the purpose of regenerating a single tissue (Caliari et al, 2011; Ferreira et al, 2012; Galatz et al, 2006; Kanungo et al, 2008; Levingstone et al, 2014; Mathew et al, 2012) to multi-compartment and spatially graded biomaterials for the express purpose of repairing more complex tissues such as the tendon-to-bone junction (Caliari et al, 2015a; Harley et al, 2010; Lipner et al, 2014; Qu et al, 2013; Smith et al, 2016; Weisgerber et al, 2015; Weisgerber et al, 2013b). Efforts in our lab have recently described two new variants of collagen scaffolds under development for osteotendinous repair applications.…”

Tunability of collagen matrix mechanical properties via multiple modes of mineralization

“…Although there is evidence that PAsp may act as an inhibitor when not bound to collagen [60]. Prior studies examining the mineralization of dense collagen scaffolds with fetuin have demonstrated similar results: mineralization occurs preferentially within the matrix, often concentrated near the surface, likely due to diffusion limitations [20,53,61]. Unlike SBF mineralization, which resulted in a two-layer composite, the addition of fetuin led to the formation of micrometre-scale inclusions leading to a particle inclusion composite.…”

“…Lines above bars indicate p , 0.05. rsfs.royalsocietypublishing.org Interface Focus 6: 20150070 techniques have been employed. These included simply immersing collagen scaffolds in solutions such as SBF or adding proteins, peptides or other chemicals to help control the mineralization process [3,20,[51][52][53][54][55][56][57]. Simple immersion of collagen leads to surface deposition of mineral either on the surface of fibrils, creating extrafibrillar mineral, or on the surface of dense collagen scaffolds.…”

What is the best candidate allograft for ACL reconstruction? An in vitro mechanical and histologic study in a canine model

“…The indentation test was performed in accordance with the previously established method(Qu et al, 2013). Samples were cut into segments (the same site as for the friction test) to a length of 2 cm.…”