Osteochondral Allograft Chondrocyte Viability Is Affected During Harvest by Irrigation Temperature and Reamer Speed

Background: Previous literature shows that current osteochondral allograft (OCA) harvesting techniques lead to donor plug chondrocyte death during OCA transplant for treating focal knee cartilage defects. Purpose: To evaluate the effects of drilling/reaming speed and irrigation temperature on chondrocyte viability during OCA harvest. Study Design: Controlled laboratory study. Methods: From each human femoral condyle (n = 9) used in the study, cartilage plugs were harvested using a powered reamer with 15 mm–diameter coring bit and continuous saline irrigation. Four experimental groups were formed according to the following parameters that were used to randomly harvest the plugs: (1) drill speed setting with room temperature (RT) saline; (2) ream speed setting with RT saline; (3) drill speed setting with cold saline; (4) ream speed setting with cold saline. A control cartilage sample was harvested with a scalpel from a macroscopically healthy region near the intercondylar notch in each specimen. Chondrocyte viability, determined by calcein and ethidium live/dead stain, was compared between groups and controls across the whole, central third, and peripheral thirds of cartilage samples. Results: Whole drill RT (P =.001) and whole ream RT (P =.004) viabilities were significantly decreased in experimental samples compared with controls. Viability at the center and periphery of drill RT plugs (P =.001 and P <.001, respectively) and ream RT plugs (P =.001 and P =.002, respectively) were also decreased. Conversely, viability was not significantly different between controls and either whole drill cold (P =.17), center drill cold (P =.24), periphery drill cold (P =.20), whole ream cold (P =.15), center ream cold (P =.24), or periphery ream cold (P =.07) samples. Viability was decreased in whole drill RT compared with whole ream RT (P =.015), but there was no difference between whole drill cold and whole ream cold (P =.26). Conclusion: Continuous irrigation with 5°C saline rather than RT saline during OCA harvest maintained donor graft chondrocyte viability in vitro. With RT irrigation, faster reamer speed induced more chondrocyte death than slower reamer speed, although this difference was mitigated with 5°C saline irrigation. Clinical Relevance: Irrigation with 5°C saline during donor plug OCA harvest may mitigate thermally induced chondrocyte damage and improve graft incorporation, healing, and outcomes of OCA transplant.