A Pre-Clinical Test Platform for the Functional Evaluation of Scaffolds for Musculoskeletal Defects: The Meniscus

Abstract

In an attempt to delay the progression of osteoarthritis from an index injury, early intervention via repair of injured musculoskeletal soft tissue has been advocated. Despite the development of a number of scaffolds intended to treat soft tissue defects, information about their functional performance is lacking. The goal of this study was to consolidate a suite of in vitro and in vivo models into a pre-clinical test platform to assess the functional performance of meniscal repair scaffolds. Our objective was to assess the ability of a scaffold (Actifit™; Orteq, UK) to carry load without detrimentally abrading against articular cartilage. Three test modules were used to assess the functional performance of meniscal repair scaffolds. The first module tested the ability of the scaffold to carry load in an in vitro model designed to measure the change in normal contact stress magnitude on the tibial plateau of cadaveric knees after scaffold implantation. The second module assessed the in vitro frictional coefficient of the scaffold against cartilage to assess the likelihood that the scaffold would destructively abrade against articular cartilage in vivo. The third module consisted of an assessment of functional performance in vivo by measuring the structure and composition of articular cartilage across the tibial plateau 12 months after scaffold implantation in an ovine model. In vitro, the scaffold improved contact mechanics relative to a partly meniscectomized knee suggesting that, in vivo, less damage would be seen in the scaffold implanted knees vs. partly meniscectomized knees. However, there was no significant difference in the condition of articular cartilage between the two groups. Moreover, in spite of the high coefficient of friction between the scaffold and articular cartilage, there was no significant damage in the articular cartilage underneath the scaffold. The discrepancy between the in vitro and in vivo models was likely influenced by the abundant tissue generated within the scaffold and the unexpected tissue that regenerated within the site of the partial meniscectomy. We are currently augmenting our suite of tests so that we can pre-clinically evaluate the functional performance at time zero and as a function of time after implantation.

Biomechanical characterization of a novel collagen‐hyaluronan infused 3D‐printed polymeric device for partial meniscus replacement

“…To our knowledge, the only previous assessment of a scaffold's ability to restore contact stresses in the knee involved Actifit . In these studies, Actifit restored mean contact pressure to intact levels, but peak contact pressure increased by 36% and contact area decreased by 20%, relative to the intact knee, similar to the results with our scaffold.…”

Platelet-Rich Plasma Can Replace Fetal Bovine Serum in Human Meniscus Cell Cultures

“…[5][6][7] A biomechanical analysis showed that the Actifit implant restores contact mechanics. 8 For total meniscus replacements, a caprolactone-urethanebased scaffold appeared mechanically too weak to cope with the high forces in the joint, and cartilage degradation was not prevented. 9,10 Tissue engineering would potentially resolve the problem of scaffolds that are initially too weak to be implanted.…”

Engenharia no Século XXI - Volume 4

“…Já, os scaffolds possuem como intuito restaurar as funções do menisco pelo crescimento tissular no interior de sua estrutura (21). Atualmente existem dois tipos de scaffolds empregados em cirurgias: o implante meniscal de colágeno (CMI®, Menaflex) e o implante de poliuretano (Actifit®), ambos são temporários e comercias na Europa para substituição meniscal parcial (lateral e medial) (14,28,(35)(36)(37). Também está em análise clinica o Nusurface® para substituição meniscal medial total (8,9,28).…”