Resorbable Pins to Enhance Scaffold Retention in a Porcine Chondral Defect Model

Abstract

Objective Cartilage repair strategies have seen improvement in recent years, especially with the use of scaffolds that serve as a template for cartilage formation. However, current fixation strategies are inconsistent with regards to retention, may be technically challenging, or may damage adjacent tissues or the implant itself. Therefore, the goal of this study was to evaluate the retention and repair potential of cartilage scaffolds fixed with an easy-to-implement bioresorbable pin. Design Electrospun hyaluronic acid scaffolds were implanted into trochlear groove defects in 3 juvenile and 3 adult pigs to evaluate short-term retention (2 weeks; pin fixation vs. press-fit and fibrin fixation) and long-term repair (8 months; scaffold vs. microfracture), respectively. Results For the retention study, press-fit and fibrin fixation resulted in short-term scaffold dislodgment ( n = 2 each), whereas pin fixation retained all scaffolds that were implanted ( n = 6). Pin fixation did not cause any damage to the opposing patellar surface, and only minor changes in the subchondral bone were observed. For long-term repair, no differences were observed between microfracture and scaffold groups, in terms of second-look arthroscopy and indentation testing. On closer visualization with micro computed tomography and histology, a high degree of variability was observed between animals with regard to subchondral bone changes and cartilage repair quality, yet each Scaffold repair displayed similar properties to its matched microfracture control. Conclusions In this study, pin fixation did not cause adverse events in either the short- or the long-term relative to controls, indicating that pin fixation successfully retained scaffolds within defects without inhibiting repair.

Marked differences in local bone remodelling in response to different marrow stimulation techniques in a large animal

“…2 defects were used for another study (36 total defects across the 6 animals). Sample size was determined based on an a priori power analysis using previous data in this animal model (Pfeifer et al, 2017).…”

“…This procedure is referred to as AMIC and has shown favourable results in comparison to MST alone 5 years postsurgery. In addition to AMIC, several laboratories have developed technologies focused on augmenting MST to direct cell differentiation and produce hyaline-like cartilage (Kim et al, 2015;Madry et al, 2020;Miller et al, 2014;Morisset et al, 2007;Patel et al, 2020;Sennett et al, 2021;Zanotto et al, 2019). Only a few of these strategies have progressed beyond the preclinical testing stage (Sharma et al, 2013).…”

Fabrication and delivery of mechano-actived microcapsules containing osteogenic factors in a large animal model of osteochondral injury

“…Bony abnormalities, including subchondral resorption, often complicate the long-term outcomes of chondral and osteochondral repair procedures, motivating localized treatment and preservation of subchondral bone [23,24,30,46,47]. Here, mechano-active microcapsules containing pro-osteogenic factors-T3 and ßglycerophosphate-were delivered to the osteochondral interface to preserve subchondral bone after nanofracture.…”

Promoting endogenous articular cartilage regeneration using extracellular matrix scaffolds

“…Glues and sutures are the most common fixation methods employed clinically, however these options are sub optimal, prolong surgery time and are liable to fail [ 34 , 35 ]. Rigid pin fixation of scaffolds and tissue engineered constructs has been performed with varying levels of success [ 34 , 36 , 37 ].…”