Assessing osteochondral allografts: moving beyond viability to define cartilage health

<h2>Abstract</h2><h3>Introduction</h3> Living articular cartilage transplantation, including osteochondral allografts (OCAs), is an established treatment for cartilage defects. Current quality control standards largely emphasize chondrocyte viability as the primary measure of graft quality. However, this narrow focus overlooks other key biological factors influencing graft health and clinical outcomes. <h3>Objectives</h3> This study aims to establish a more comprehensive evaluation framework for OCAs by incorporating assessments of apoptosis, metabolic activity, matrix integrity, and histological staining alongside traditional viability measures, offering a fuller representation of cartilage and OCA functionality. <h3>Methods</h3> OCAs from donors aged 36 to 39 years were analyzed for chondrocyte viability, cellular functionality, and matrix integrity. Conventional viability assays (trypan blue, LIVE/DEAD) were compared with apoptosis detection (flow cytometry), metabolic activity (PrestoBlue), and matrix protein composition quantification (proteoglycan-4 and sulfated glycosaminoglycan). Histological staining (Hematoxylin and Eosin, Alcian Blue, Safranin-O) provided structural characterization of the cartilage matrix. <h3>Results</h3> Quantitative and qualitative analyses revealed discrepancies between assessment methods. LIVE/DEAD analysis reported 75.99% viability, while trypan blue yielded 94.29%. Flow cytometry results (88.00%) correlated closely with trypan blue findings, suggesting intact cell morphology. Metabolic and matrix assays supported these results, confirming the need for multi-parameter evaluation. <h3>Conclusions</h3> The methods proposed here address the limitations of current approaches by utilizing multiple parameters to ensure a thorough and comprehensive evaluation of OCAs beyond viability alone with a goal of better predicting success and performance clinically.