I'd like to thank Anna, and Dr. Kelly, and the program committee for allowing us to present our paper and acknowledge my co-authors, and in particular, Simon Lee, who's the lead author on this project. My disclosures are available in the final program and online. As we all know, osteochondrialgraft transplantation is associated with good to excellent clinical outcomes and low failure rates when appropriately indicated and appropriately performed. Indications for this procedure typically involve revision, cartilage restoration, cartilage problems that have associated bony involvement, bipolar cartilage lesions, large cartilage lesions, among others. The question is, how big is big enough to do an osteochondrial transplant? And does size matter when it comes to these cartilage procedures? Most cartilage studies suggest that large lesions do worse, regardless of the procedure that you're doing, whether it's a cell-based transplant or a structural-based transplant. The question we had is absolute size versus relative size. How big is that defect relative to the size of the condyle? 10 millimeters is not the same for every patient, particularly if you have a very small condyle. So the purpose of this study was to quantify survival and clinical outcomes of isolated osteochondrial allografts in knees without major concomitant procedures based on defect size and the defect size to condyle ratio, which we'll call DCR. We hypothesized that patients with larger sizes and larger DCRs would have worse outcomes and higher failure rates. To perform this, we conducted an analysis of consecutive patients undergoing isolated osteochondrial allograft transplantation of either the medial or lateral femoral condyle of the knee. Not the patella, not the trochlea. Minimum defect size was one centimeter squared. Minimum follow-up was two years. And then we measured patients' defect size and the condyle size. As you can see here, the defect size was measured intraoperatively by the surgeon. The condyle size was measured on preoperative AP and lateral radiographs. And then we took a ratio of the defect size to the condylar area and called that, again, the DCR. We had 68 patients. Average age of 35 years. 43% of the cohort was female. Average BMI was 28. The patients had previously had an average of two average prior surgeries on the ipsilateral knee. And the overall follow-up was an average of five years with, again, a minimum of two years. About 2 3rds of the cohort had medial femoral condyle transplants, whereas the other 3rd had lateral femoral condyle transplants with an average defect size of just over 4 centimeters squared. And the average DCR was 0.2, so meaning approximately 20% of the condyle was involved in the transplant. We found that in males, the defect size was significantly larger compared to females. So 4 centimeters squared compared to 2.8 centimeters squared on average. But the ratio was no different between males and females. Thus, showing that females have a smaller condyle size in general, which has been shown in previous studies. When we look at our patient-reported outcomes, we showed that for all of the patient-reported outcomes assessed in this study, we had significant improvements with the exception of the SF-12 mental subscale score, which did not show significant improvements. All others showed significant improvements in the overall cohort. There was an overall reoperation rate of 40% at an average of 2.5 years after surgery, with no differences in reoperations based on age or sex, and no correlation with the defect size or the DCR. There were eight failures in this cohort, approximately 12% at an average of 2.6 years. Four underwent revision osteochondroallograft transplantation, and the other four converted to arthroplasty. There was no difference in failures based on age or sex. When we looked at the defect size and defect size ratio, what we saw was that failures had significantly higher defect size to condylar ratios, 0.26 versus 0.19. And they trended toward an overall higher defect size, although that was not statistically significant. When we substratified by age, we found that in patients greater than or equal to 40, they had larger defect size among those patients who failed, and larger DCRs. And that failures over 40 didn't really differ based on their defect size. But again, if you were over 40, you overall had a larger defect size. So at an average of five years following osteochondroallograft transplantation in this cohort, and this is isolated osteochondroallografts, there's a very high survival rate. Of the patients who fail, there's higher defect size to condyle ratios, and that's in particular in the older patient population with no differences between males and females. When we look at older patients, we've previously assessed if osteochondroallograft can be performed in older patients, and the answer is yes. But this current study does give us some pause and tells us that older patients with bigger lesions relative to the size of the condyle may be more likely to fail following osteochondroallograft transplantation. This study is limited in that it's retrospective and with a single surgeon, so it's not necessarily extrapolatable to the general population or to the patellofemoral joint, and was not performed with concomitant procedures. So again, in conclusion, with appropriate indications, we have a high success rate after osteochondroallograft transplantation of the knee. We do need to be cognizant of the defect size relative to the size of the condyle in the older patient population. Thank you very much.

gratitude

paper presentation

osteochondral graft transplantation

defect size

condyle ratio