Improved Preservation of Fresh Osteochondral Allografts for Clinical Use

Abstract

Introduction Fresh osteochondral allografts (OCAs) have been used clinically to treat cartilage focal defects of the knee for over 30 years. Over the last decade, significant research has been performed to develop and improve protocols for preservation of osteochondral tissue before transplantation into patients for treatment of cartilage defects. This work has resulted in preservation protocols that allow for maintenance of OCA tissues for time periods sufficient for clinical use based on disease testing requirements in the United States. However, graft quality and the window for clinical use of these tissues could be greatly enhanced from current levels. Materials and Methods Femoral condyles from 14 dogs were harvested and stored in one of the three proprietary media composition (M-1, M-2, M-3) and container condition (C-1, C-2, C-3) at 25°C for 63 days. Viability of the OCA was determined using a proprietary media metabolic assay and live cell fluorescent microscopy. Media biomarker concentrations were analyzed to determine the metabolic activity of tissue. Results Media protein biomarkers were detected throughout the culture period, indicating OCAs remain metabolically active at 25°C, and biomarker levels correlated with tissue viability. Viable chondrocyte density was maintained at day 0 levels throughout the depth of the tissue in the M-3 media using container condition C-3 after 63 days in storage. The media metabolic assay correlated strongly to cell viability of the OCA tissue. Conclusion These data indicate that near day 0 tissue viability can be maintained for up to 63 days when OCAs are stored at 25°C in the correct conditions. Further, tissue viability could be assessed nondestructively using media biomarkers and the media metabolic assay. If the preservation protocol reported here can be validated for safety and functional outcome, it could then be employed in tissue banks throughout the world, decreasing the number of grafts discarded and improving quality of life for thousands of patients affected by cartilage defects.

Large Fresh Osteochondral Allografts of the Knee: A Systematic Clinical and Basic Science Review of the Literature

“…28 More recent studies have reported better results storing grafts at 37 C or room temperature. [20][21][22][23][24][25][26] These findings would lead to the potential of the allografts tolerating a longer storage time, but other factors need to be taken into consideration such as the risk of infection. 21 Changes in subchondral bone and the formation of bone cysts around implanted allografts have been studied by Pallante et al 15 The main concern in their study was the effect of the overlying cartilage layer on the subchondral bone and the incorporation/healing of the adjacent host bone and cartilage, and further investigation is needed to optimize healing and minimize the transitional area between allograft and recipient.…”

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28] Cellular viability has always been considered one of the most important factors for successful osteochondral allograft transplantation. The effects of different storage times and different media on cellular viability have been widely studied in the past.…”

“…Application of hyaluronan diminishes this rise. Bardos et al 26 2009 Porcine knee joints (20) Comparison of 3 techniques: bone marrow stimulation, ACI, and processed chondrograft Good osteochondral integration of the processed chondrograft was found; the resulting tissue appeared to be hyaline cartilage. No immune-surveillance reactions were shown.…”

“…Stoker et al 20 hypothesized that osteochondral tissue can be preserved at room temperature for at least 56 days with viable chondrocyte density maintained at 70% of harvest level and that tissue viability could be assessed nondestructively using media biomarkers. The medial and lateral femoral condyles of 14 adult canine cadavers were harvested and stored in 1 of 3 proprietary media compositions (nutritive, antidegradative, and antiinflammatory media) in 3 different container conditions at 25 C without carbon dioxide supplementation.…”

Cartilage storage at 4 °C with regular culture medium replacement benefits chondrocyte viability of osteochondral grafts in vitro

“…Several studies report that ex vivo storage of articular cartilage is better at 37 °C compared with 4 °C (Bastian et al 2011; Bian et al 2010; Pallante et al 2009). However, the issue with graft storage at 37 °C is that microorganism growth can occur, which increases the infection risk and contributes to high storage costs (Stoker et al 2012). Storage at 4 °C in a tissue bank has been the standard approach for many years, with the advantages of low risk of microbial infection, low storage cost, and an approach that is more widely accepted (Bae et al 2009; Bian et al 2010; Linn et al 2011; Malinin 2006; Onuma et al 2012; Williams et al 2004).…”