Little is known about the long-term properties of fresh cold-stored osteochondral allograft tissue. We hypothesized fresh
cold-stored tissue would yield superior material properties in an in vivo ovine model compared to those using freeze-thawed
acellular grafts. In addition, we speculated that a long storage time would yield less successful grafts. We created 10-mm
defects in medial femoral condyles of 20 sheep. Defects were reconstructed with allograft plugs stored at 4°C for 1, 14, and
42 days; control specimens were freeze-thawed or defect-only. At 52 weeks, animals were euthanized and retrieved grafts were
analyzed for cell viability, gross morphology, histologic grade, and biomechanical and biochemical analysis. Explanted cold-stored
tissue had superior histologic scores over freeze-thawed and defect-only grafts. Specimens stored for 1 and 42 days had higher
equilibrium moduli and proteoglycan content than freeze-thawed specimens. We observed no difference among any of the cold-stored
specimens for chondrocyte viability, histology, equilibrium aggregate modulus, proteoglycan content, or hypotonic swelling.
Reconstructing cartilage defects with cold-stored allograft resulted in superior histologic and biomechanical properties compared
with acellular freeze-thawed specimens; however, storage time did not appear to be a critical factor in the success of the
transplanted allograft.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the animal protocol for this investigation and that all investigations
were conducted in conformity with ethical principles of research.