Foot & Ankle International - 2017 FAI Supplement - 36S

Effects of Micronized Cartilage Matrix
on Cartilage Repair in Osteochondral
Lesions of the Talus
Christopher Kreulen, MD, Eric Giza, MD, Alvin
Shieh, MD, Sohni Singh, BS, Connor Nathe, BS,
Evan Lian, BA, Dominik Haudenschild, PhD
Category: Ankle, Arthroscopy, Sports
Keywords: osteochondral lesion, talus, OLT, biocartilage,
OCD
Introduction/Purpose: A promising new technique in the
treatment of osteochondral lesions of the talus (OLT)
involves the use of an acellular micronized cartilage matrix
(MCM), BioCartilage, to fill the lesions. The micronized
cartilage matrix is thought to improve the production of
hyaline-like cartilage by resident cells in a cartilage defect,
but its effect on bone marrow cells remains untested. Here
we hypothesized that adding bone-marrow derived stem
cells to the BioCartilage would result in the chondrogenic
differentiation of the stem cells. We designed an in-vitro
model to mimic the clinical situation to determine if the
combination of MCM and human bone marrow derived
mesenchymal stem cells (MSCs) would produce a hyalinelike cartilage in-vitro to ultimately provide a reliable, onestep treatment for osteochondral lesions in the talus.
Methods: Human bone marrow-derived stem cells were
obtained from consented patients and expanded in monolayer culture using standard protocols, to a maximum passage of 4. Viability was measured using Live/Dead cell
viability assays (Thermofisher), and imaged on a Nikon
TE2000 inverted fluorescent microscope. A custom-manufactured polysulfone device was created with four 6mm
diameter 3mm deep indentations in agarose within each well

36S

of standard 6-well culture plates (Figure 1A-C). In each
well, we placed chrondrogenic media with cells+micronized
matrix to a depth of 2mm and covered with a 1mm layer of
TISSEEL fibrin glue as is done clinically. Control groups
had either no cells, or no MCM. At the end of 3 weeks, cartilage constructs were extracted and divided to perform viability, histology, and gene expression analysis (Figure 1D).
Experiments were performed with 4 technical replicates, and
repeated at least 3 times. Statistical analysis was performed
using ANOVA with Dunnett's test.
Results: We found that stem cells were almost immediately
killed when added directly to the dry micronized cartilage powder. Rehydrating the micronized cartilage prior to addition of
cells was required to maintain the viability of the added stem
cells, with no statistically significant difference between rehydration with serum or saline. After 3 weeks of culture in chondrogenic media, we observed that the combination of stem cells
and micronized cartilage produced a cohesive structures that
were easily handled, suggesting chondrogenic differentiation of
the stem cells. Without the micronized matrix, the stem cells did
not form viable constructs. In constructs that contained both
cells and micronized cartilage, the 3-week cell viability was
over 98%, with no dead cells visible in many constructs.
Conclusion: Our study demonstrates that the micronized
cartilage matrix is a suitable scaffold for the chondrogenic
differentiation of bone marrow-derived stem cells, given that
the matrix is first rehydrated before adding cells. Technical
observations include that the MCM itself generated a "dead
cell" signal initially, therefore the normalized total number of
live cells in each condition was used for statistical comparisons. After 3 weeks of culturing under chondrogenic media
conditions, we observed robust cell survival with nearly
100% viability. Preliminary results suggest cartilage matrix
deposition occurred surrounding the cells after 3 weeks of
chondrogenic culture.

Foot & Ankle International 38(1S)

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