Hello everyone. Thank you for having me here today. So, today I present the association of sex mismatch between donor and recipient with graft survivorship at five years after osteochondralograft transplantation. So, these are our disclosures. So, as the audience may be aware, osteochondralograft transplantation is an effective strategy to treat large heart defect. However, broad rates of graft survival are still reported, and this large variation may be related to both patient and donor factors. So, several studies have investigated predictors for OCA failure, which includes patient or recipient factors such as increased BMI, age or lesion size, and also graft factors such as graft viability before implantation and time of graft storage. And another factor that may contribute to the OCA performance is the sex and, in particular, the sex matching between the patient and the donor. So, we have learned from solid organ transplantation that sex mismatch is a potential contributor for adverse outcomes being negatively associated with several solid organ transplantations such as lung, heart, pancreas, kidney, and liver transplantation. And these may be related to physiological mismatch and the immune response. So, based on this background, the aim of our study was to explore the potential effect of donor-recipient sex mismatching on OCA transplantation in the knee. So, patients from one single surgeon that underwent OCA transplantation from 2013 to 2017 with a minimum of two years follow-up were included. Definition of graft failure was subchondral collapse of the OCA, removal or revision for the primary OCA, or conversion to any kind of arthroplasty. So, 154 patients were included, being 102 in the sex matched group and 52 in the sex mismatched group. And in terms of failure, an overall failure rate of 11.7% was reported, with 6.9% in the sex matched group and 21.2% in the sex mismatched group. So, looking to the five-year survival group, we can see that sex matched allografts have had a cumulative survival of 92%, while sex mismatched allografts had a cumulative survival of 63%. And when controlling this data for the patient's BMI, age, and allograft size, we found that sex mismatched OCAs were 2.9 times more likely to fail compared to sex matched allografts. We further divided this case by each sex condition and we could see that in the male-to-male combination, a cumulative survival of 92% was found, while in the male-donor-to-female recipient, we found a cumulative survival of 63%. And again, when controlling the data for BMI, allograft size, and age, we found that male-donor-to-female recipient had 2.6 times higher likelihood of failure in comparison to the other combinations. So, based on these findings, two main questions appeared in our study. One is, why does sex mismatch increase the OCA failure rate? And two is, why does male-to-female have the worst survivalship? So, those questions were not on the scope of our study, but we know that some anatomical factors such as sex difference in the distal femoral dimensions, cartilaginous thickness and density, and also immunological factors such as the minor histocompatibility antigen, or a higher immunological response after pregnancy, or even other factors such as blood type and HLA monotypes may contribute to this difference in the outcomes. So, in conclusion, sex mismatch when using fresh OCA transplantation results in lower rates of OCA survival at 5 years when compared to sex matched groups. And after adjusting for patient's age, graft size, and patient BMI, we could see that sex mismatch had a 2.9 times higher likelihood of failure in comparison to sex matched allografts. And also that male-to-female mismatch had a 2.6 times higher likelihood of OCA failure. So, as a final consideration, efforts to avoid donor-recipient sex mismatch when and if possible may enhance the long-term success of the fresh OCA transplantation. Thank you.

sex mismatch

graft survivorship

osteochondral allograft transplantation

graft failure

donor-recipient sex matching