Cell-Laden and Cell-Free Matrix-Induced Chondrogenesis versus Microfracture for the Treatment of Articular Cartilage Defects

Abstract

Objective:The aim of this study was to evaluate the regenerative potential of cell-laden and cell-free collagen matrices in comparison to microfracture treatment applied to full-thickness chondral defects in an ovine model.Methods:Animals (n = 30) were randomized into 5 treatment groups, and 7-mm full-cartilage-thickness defects were set at the trochlea and medial condyle of both knee joints and treated as follows: 2 scaffolds in comparison (collagen I/III, Chondro-Gide®; collagen II, Chondrocell®) for covering microfractured defects (autologous matrix-induced chondrogenesis), both scaffolds colonized in vitro with autologous chondrocytes (matrix-associated chondrocyte transplantation), or scaffold-free microfracture technique. One year after surgery, cartilage lesions were biomechanically (indentation test), histologically (O’Driscoll score), and immunohistochemically (collagen type I and II staining) evaluated.Results:All treatment groups of the animal model induced more repair tissue and showed better histological scores and biomechanical properties compared to controls. The average thickness of the repair tissue was significantly greater when a scaffold was used, especially the collagen I/III membrane. However, none of the index procedures surpassed the others from a biomechanical point of view or based on the histological scoring. Collagen type II expression was better in condylar defects compared to the trochlea, especially in those treated with collagen I/III membranes.Conclusion:Covering of defects with suitable matrices promotes repair tissue formation and is suggested to be a promising treatment option for cartilage defects. However, it failed to improve the biomechanical and histological properties of regenerated articular cartilage compared to microfracture alone in an ovine model under the given circumstances.

Unlike Bone, Cartilage Regeneration Remains Elusive

“…For example, while fibrocartilaginous repair tissue from microfracture results in initially enhanced clinical knee function scores, over 2 years it degrades and scores decline (9). Scaffolds used with microfracture enhance hyaline quality and increase fill percentage, but fibrous tissue still results (11). In conjunction with matrix formation, MSC anti-inflammatory effects may be important in alleviating symptoms (12).…”

“…This enables materials, such as porous hydroxyapatite, to provide initial stability and, following in vivo maturation, recapitulation of bone biomechanical properties. In contrast, evidence exists that cartilage repair techniques, including ACI and microfracture, are unable to replicate the biomechanical properties of native tissue (11, 26). …”

A randomized controlled trial demonstrating sustained benefit of Autologous Matrix-Induced Chondrogenesis over microfracture at five years

“…The principle of the AMIC ® technique was proven in a sheep model [8]. So far, promising clinical results with the AMIC technique were reported by case series only [9,10].…”

Autologeous matrix induced chondrogenesis (AMIC) for treating articular cartilage defects of the lower limb: A clinical overview

“…The first area of application was the knee joint but meanwhile it is a standard procedure at the hip and ankle joint and has been described for the first metatarsophalangeal join, too 9,24,26 . First in vitro and animal studies showed an enhanced defect filling and higher quality of the repair tissue when a collagen I/III matrix was used and so the authors concluded that repair tissue formation is encouraged when a collagen I/III matrix is used [4][5][6] . Regarding the AMIC technique in the knee joint several studies could show that this method is an effective and safe method of treating fullthickness chondral defects 8,9,[11][12][13] .…”

“…. In an ovine model with a followup period of 12 months, the average thickness of the repair tissue was significantly greater when a scaffold was used, especially a collagen I/III membrane 6 . No differences were detected when comparing cell-free and cell-laden collagen membrane biomechanically and histologically.…”