Due to recent advances in diagnostic technology and an increased awareness among clinicians, osteochondral damage is being detected more frequently. Thus, there is a need to preserve and store articular cartilage for the repair of joint surfaces. Chondrocytes, embedded within extracellular matrix must remain viable during storage for successful tissue transplantation. We have been able to store osteochondral tissue for over a month and maintain high chondrocyte viability. Apoptosis can be minimized in articular cartilage during hypothermic storage if biopreservation media (XVIVO-10) is used. Cadaveric osteochondral dowels are a potential source of tissue for banking and allogeneic transplantation.

The purpose of this study was to:

Establish a timeline and optimal conditions for storing human articular cartilage (AC).

Forty fresh human AC samples from femoral condyle notchplasties were used to determine a storage timeline. Each sample was divided into three portions:

initial chondrocyte viability,

All samples were randomly allocated to one of five time intervals (2–10 weeks). Following each time period final viability assays were conducted. Secondly, osteochondral dowels were drilled from eight cadaveric femoral condyles. Five dowels were obtained from each joint: one for initial viability/annexin V assays, the others were stored in PBS or XVIVO-10 for four and six weeks. Following storage, final viability, annexin V, and TUNEL assays were preformed.

Notchplasty samples stored in XVIVO-10 for four weeks had an average final viability of 68%, but an average loss in viability of only 6%. By one month the viability of samples stored in PBS had dropped to 5%. Osteochondral dowels stored in XVIVO-10 not only had greater chondrocyte viability, but less apoptosis.

Cadaveric dowels are a suitable source of osteochon-dral tissue for hypothermic storage and in turn allogeneic transplantation.

An osteochondral tissue bank would provide a reliable source of articular cartilage for repairing joint surfaces for patients who are not suitable candidates for total joint replacements.

Osteochondral allografts (frozen uncontrolled, or cryo-protected with dimethyl sulfoxide) were transplanted into medial femoral condyles of eighteen sheep. Cores from the ipsilateral graft site served as autografts for the contralateral limb. Analysis of graft and host cancellous bone microarchitecture by μCT at three months post transplant demonstrated no significant differences among the treatment groups. Dramatic bone resorption at the graft–host interface, however, occurred in up to 1/3 of condyles from all treatment groups, including fresh autografts suggesting that factors other than donor source or tissue storage played an important role in the bone incorporation of osteochondral grafts.

The purpose of this study was to study the effect of different freezing protocols on periarticular cancellous bone architecture after osteochondral allograft transplantation.

There were no significant differences in graft or host cancellous bone architecture among the groups (autografts, frozen allografts, cryopreserved allografts). Dramatic resorption of graft bone in condyles from all treatment groups suggested that factors other than donor source or tissue storage played important roles during incorporation of osteochondral grafts.

Graft positioning, graft orientation, and recipient bed necrosis may play significant roles during incorporation of osteochondral graft bone.

Osteochondral allografts (10 mm diameter) were transplanted into medial femoral condyles of eighteen skeletally mature Suffolk ewes. Allografts were frozen (–80°C) without cryoprotectant (FROZ) or treated with dimethyl sulfoxide (cryoprotectant) and frozen (–80°C at 1°C · min⁻¹) (CRYO). Osteochondral cores removed from ipsilateral graft sites served as fresh autografts (AUTO) for the contralateral medial femoral condyles. Condyles were harvested at three months and scanned (micro computed tomography –μCT). Three dimensional μCT data of graft and host cancellous bone regions were analyzed for bone volume fraction, trabecular thickness, bone surface–volume ratio, and trabecular anisotropy. No morphological differences were found among treatment groups. Excessive bone resorption of graft and interface precluded analysis of some samples from each group (ALLO — 2/9, CRYO — 3/9, AUTO — 6/18). Dramatic bone loss did not correlate with poor graft orientation, placement, infection, or recipient–bed necrosis, but a combination of these factors may contribute to excessive cancellous bone resorption in osteochondral grafts.

Funding: Medical Research Council of Canada, Canadian Institutes of Health Research, No commercial funding

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