Diffuse Host Bone Marrow Edema on Six-Month MRI is a Risk Factor for Osteochondral Allograft Failure.
Academic Article
Overview
abstract
PURPOSE: The purpose of this study is to evaluate the presence of host Bone Marrow Edema (BME) surrounding osteochondral allograft plugs on routine 6-month postoperative Magnetic Resonance Imaging (MRI), and to determine whether such BME is correlated with subsequent failure. METHODS: The present study was approved under our institutional review board-approved database (#2020-2123). We included patients who underwent cartilage repair with OCA for focal chondral and osteochondral defects of the distal femur by two senior surgeons between January 2016 and May 2021 with minimum 2-year follow up. OCA is frequently performed with concomitant procedures, and therefore ligament reconstruction, meniscal surgery, and osteotomy were not exclusion criteria. Failure was defined as (1) poor clinical outcome with graft collapse on follow-up MRI or second-look arthroscopy, (2) primary OCA removal or revision, or (3) conversion to unicompartmental or total knee arthroplasty. Routine MRI scans were performed at 6 months (± 2 months) post-op. All post-operative MRI scans were reviewed from our imaging record by two blinded fellowship-trained orthopedic surgeons. Patients were divided for analyses into two groups: BME ≥ 10 cm3 vs. BME < 10 cm3. RESULTS: Of the 85 patients eligible for the study, 56 patients (30 female, average age 31.69 ± 11.34 years) had a minimum of 2-year follow-up. Non-failure cases had a mean clinical follow-up of 3.13 ± 0.93 years. The mean time from surgery to failure in our cohort was 1.67 ± 0.91 year. There were 12 (21.4%) patients with BME ≥ 10cm³ and 44 (78.6%) patients with BME < 10cm³. No statistically significant differences were found between groups when compared for sex, age, BMI, OCA size, time to MRI, mean follow-up, number of plugs, graft location, diagnosis, previous surgeries, or concomitant procedures. All OCA failures of the study cohort were in the BME ≥ 10cm³ group, representing 50% of this group (p < 0.001). Kaplan-Meier survival analysis with the log-rank test demonstrated significant difference in survival distributions between groups (p < 0.001). Patients who ultimately failed had a mean BME volume of 18.49 ± 5.82 cm3, while the non-failure group had a mean volume of 4.66 ± 4.97cm3 (p < 0.001). Cutoff values around to 10cm³ in ROC Curve Analysis demonstrated 100% sensitivity and close to 90% specificity for OCA failure diagnosis. CONCLUSION: Host bone marrow edema with a volume greater than 10cm³ on 6-month postoperative MRI is predictive of an increased subsequent failure rate after OCA transplantation with a failure rate of 50%.
