of a multi-center anterior cruciate ligament revision study. What have we learned? Lots. I have nothing to disclose. So from 2006 to 2011, 1,234 patients were enrolled, having undergone revision ACL. Fifty-two sites, 83 surgeons, 55% of which were in private practice, which I think adds value to this study. 92% two-year follow-up, with additional six-year and 10-year follow-up, 83 surgeons. Thank you to them all. This is the Scientific Advisory Board, and I want to give a special shout-out to Laura and Amanda, because hurting 83 surgeons is a very difficult task, and they did it well. The purpose of MARS was to perform a multi-surgeon, multi-center, prospective longitudinal study using multivariate analysis to determine predictors of clinical outcome. There have been over 28 publications, most of them AGSM, over 50 presentations with those two awards. The publications are listed in your handout. Preoperatively, thorough history, physical exam, as well as five-view radiographs. The patients filled out a questionnaire that was 13 pages long. They did it preoperatively at two-year follow-up and six-year follow-up. The surgeons had a 201-question, 49-page form to fill out. All were required to attend a training session, and all had IRB approval. The PROs that we used, the patient-reported outcomes included COOS, IDKC, WOMAC, SF36, and MARCS. So, we're now approaching a half-million ACL surgeries per year in the U.S. So, what do you tell your patients when you give informed consent, because it's variable in the literature? Well, here's one simple, two simple studies. Moon, two-year follow-up, 3% ipsilateral graft failure, 3% contralateral ACL tear. Dr. Wright and his 2019 systematic review of five-year follow-up, 5.8% ipsilateral, 11% contralateral. Of course, there's many causes for poor outcomes, more than just graft failure. Cartilage injury, meniscal injury, pain, arthritis, loss of motion, stiffness, weakness, atrophy, et cetera. The surgeon listed the causes of failure as either traumatic, technical, biological. Traumatic was the most common, accounting for at least 55% with some overlap. The variables, there were over 88 independent variables studied. Some were modifiable, some were not. Modifiable included graft choice, fixation choice, rehabilitation, bracing, surgical technique. There were 58% males, median age was 26. Graft choice is relatively evenly split between autograft and allograft, and both soft tissue and bone tendon bone. The revision number, the vast majority were the first revision, although a spattering of up to the fifth revision ACL. Surgeon's own failure, 28%, which also adds value to the paper. The time from the last ACL, the majority were over two years, but certainly a significant proportion under two years. Articular cartilage injury or meniscal pathology, either or was present in 91% of the patients. There were 18% that had meniscal repair, with a failure rate about 8.6% at two years. Bone grafting was done more commonly staged, as opposed to at the time of revision in equal numbers between femur and tibia. The mechanism of injury, 73% state they were injured playing a sport, and the most common being soccer. So what have we learned? Well, graft re-rupture, this is an important slide. Two-year graft re-rupture is 3.3%, and allograft up to three times more likely. Six-year graft re-rupture, 5.8%. Again, allograft almost four times more likely. In fact, if you compare bone tendon bone of allograft versus autograft 4.2 times more likely graft rupture in the allograft. Now, if you compare bone tendon bone to soft tissue, with autograft no difference and with allograft no difference, and the surgeon was five times the strongest determinant of the graft choice. So a younger age than 26 was also a significant risk. The second most common cause of failure was technical. Infemoral malposition accounted for 80% of those. Poorer PROs at two years, independent predictors, lower baseline PROs, higher BMI, female, shorter time between primary, ACL, and revision. Previous lateral mastectomy in grade three or four changes in the trochlea. Improved PROs at two years, independent predictors, autograft, metal interference screw in the femur, no notchplasty, no biological enhancement, no femoral bone graft, but did include tibial bone graft. Decreased two-year activity level, independent predictors, lower baseline activity level, female, older age, smoker, and previous ACL injury and reconstruction on the other knee. Marks activity levels, non-predictors, and this is kind of interesting. Previous and current meniscal or articular cartilage injury and the number of revision ACL, non-predictors for marks activity level. So, six-year follow-up, 77%. Bone tendon bone autograft had higher activity level than bone tendon bone allograft. The PROs all significantly improved, but interestingly, the marks significantly decreased compared to baseline and two-year follow-up. Autografts significantly better than allografts for the six-year marks. Reoperation rates, 16% at six years, 11% at two years. Autograft was a significant predictor of fewer operations in age less than 20, significantly increased risk. Here's in descending order, the reoperations most commonly was the meniscus, then another revision ACL, articular cartilage injuries, or additional surgery, hardware removal, or arthrofibrosis treatment. So, now we're going to compare multiple revision ACL versus single. So, meniscal transplants were actually quite uncommon laterally and only in the single. In the medial side, more commonly done in the multiple revision ACL. Allograft choice for the single revision ACL, more than half. But when you talk about multiple revision ACL, 75% were autograft. Staged bone grafting, much more common for the multiple revision ACL compared to the single. Multiple ACL, again, comparing single ACL, lower activity level, increased chondral injuries, increased rate of non-traumatic recurrent graft injury. Sports participation at two years, no sports participation in the entire cohort had lower PROs at baseline in two years versus those compared to single or multi-sports. No sports, or almost doubled at two years. Single sport actually increased at two years, and multi-sport decreased. And so, return to activity of any kind, 85% of those active at baseline did return, but 20% of those had worse PROs. But no difference in PROs by participation level. I'm going to skip bracing, but graft re-rupture was not affected by brace. And radiographs, again, almost half had anterior position of the femoral tunnel, and almost half had some impingement when assessing the tibial tunnel. Now, all patients had a hyperextension lateral obtained, and those that had over 5% hyperextension accounted for 33% of the patient, and two times higher odds of re-rupture of the ACL graft. So, the rover and Mars, both are still collecting data, both will lead to new means of testing science, both will lead to new discoveries, and both will lead to improved outcomes in science. Thank you.

MARS study

ACL revision surgery

graft re-rupture rates

femoral malpositioning

reoperation rates