Effects of Osteochondral Allograft Reaming Protocols on Donor Chondrocyte Viability Prior to Transplantation.

Abstract

This preclinical ex vivo study was conducted to evaluate the effects of submersion in saline or the Missouri Osteochondral Preservation System (MOPS®) solution during reaming on viable chondrocyte density (VCD) of osteochondral allografts (OCAs). Distal femoral OCAs preserved with MOPS were reamed to create cylindrical "plug" grafts using one of three techniques: Submersion in MOPS (SG-MOPS), submersion in saline (SG-Saline), or reamer saturated with MOPS without OCA submersion (SR-MOPS). All plug reaming was performed using standardized instrumentation and technique to harvest 18-mm-diameter plugs. Pre-reaming cartilage samples were collected to confirm baseline VCD. Post-reaming plugs were bisected and stained for live/dead analysis using fluorescent microscopy. VCD was quantified via image analysis, and %Day-0 VCD was calculated. Group comparisons were made using one-way analysis of variance (ANOVA; α = 0.05). A total of 21 plugs from 9 donors were analyzed: SG-MOPS (<i>n</i> = 8), SG-Saline (<i>n</i> = 6), SR-MOPS (<i>n</i> = 7). Mean %Day-0 VCD was highest in SG-MOPS (92.6 ± 7.8%), followed by SG-Saline (83.3 ± 10.2%), and SR-MOPS (80.2 ± 9.1%), though differences were not statistically significant (<i>p</i> = 0.68). A higher proportion of SG-MOPS plugs (7/8, 88%) exceeded the minimum essential VCD threshold (70%) compared with SG-Saline (4/6, 67%) and SR-MOPS (3/7, 43%). Submerging distal femur OCAs in MOPS during 18-mm-diameter femoral condyle plug reaming had clinically meaningful beneficial effects on viable donor chondrocyte density when compared with saline-submerged or non-submerged grafts. Based on the use of this submerged reaming technique that is standardized, repeatable, readily available, cost-effective, and safe, this methodology can be considered "best practice" for OCA plug reaming protocols, motivating implementation of this evidence-based shift in practice at our institution.