My name is Dr. Andrew Gieseland. I'll be giving the talk, ACL Primary Repair, Is There a Role? And I've been assigned the no portion of the debate. These are my disclosures. We need to talk about this in the context of the overall history. We'll be reviewing the reconstruction data and specifically the moon data. And then we'll go over the more modern repair techniques. The early history was written by Battle and Robson over a hundred years ago, where ACL repair was described. Campbell and O'Donohue, with an image shown here at the right, also described repair and considered reconstruction if necessary. Dr. John Fagan, a legend in this field, described 18 to 20 year old West Point cadets with two-year data in 1972, and they had 83% good and excellent results. However, the five-year data was presented in 1976, and 16 of the 32 patients required re-exploration. Only eight of them had an intact ACL, and there were 12 meniscus tears. And this was felt to be the end of ACL repair. And as you can see from an excerpt from his paper, he felt that the blood supply, which was well-described, was too meager to base surgical repair by the present methods. Doesn't rule it out for the future, but based on the present methods available at that time in the 1970s. The field as a whole moved towards reconstruction at that time, and several different techniques have been described. We'll focus on the Moon ACL reconstruction data, as I think this serves as the great model for studies and also provides a very detailed description of the patient group. And they've published over 60 publications on this patient group. And last year in 2020, they published their data on subsequent surgery within six years of the primary ACL reconstruction. There were over 3,000 patients with over 90% six-year follow-up, which was excellent. The mean age is 23 years. This is clearly a young cohort. 20% of the patients within six years had to have revision surgery, with 11.9% of the meniscus and 7.5% revision ACL reconstruction. With that in mind for the reconstruction, we can review repair data. And it's important to know that there are multiple techniques described for repair. There are some of the older primary repair techniques with suture repair. More recently, Dr. Murray and her group have described a scaffold repair. And this has been a very robust clinical study that's based on a lot of basic science research in the lab. And there have also been techniques described for repair with internal stabilization with suture, as you can see at the bottom right. One study in adolescents reported repair results versus reconstruction. And the patient age was seven to 18. So clearly a large patient group with different levels of skeletal maturity. And they reported their three-year failure rate with 48.8% failure rate in repair and an order of magnitude less with reconstruction at only 4.7%. And they felt that repair was associated with an unacceptably high failure rate in this patient group with this technique. Dr. DeFelice is clearly a leader in this field. And he published his early results in 2015 with 11 patients with an older patient group than we saw in the MOON data, which was 23. Here it's 37, but with a range of 17 to 57 years old. He excluded patients with multiple ligament injuries as well as those with irreparable ACL tears. And they had three and a half year follow-up data on this patient group. And nine patients had IKDC level A and overall good results with this technique. He later published data on patients that underwent the surgical procedure with three different age groups, less than 21 years, 22 to 35, and greater than 35 years. And a very large study with 27, 24, and 62 patients in those age groups. And he described failure as occurring in patients that had greater than or equal to level two Lachman or pivot shift test, as well as those with a re-rupture on MRI. And if you look at the area in the orange box, the patients that were less than 20 years or 21 years, 10 of the 27 failed. So a failure rate of 37%. And if you look at the two older age groups, there was just four and 3% failure rate. And they concluded that you have to proceed cautiously with repair in the young patient group, or that it may be well-suited for patients in an older patient group. A large systematic review of over 2,400 patients was performed recently and published in 2019, mostly based on European level four studies. Half of the patients ultimately had a primary suture repair and half had a dynamic infraligmentary stabilization. Within the proximal repair subgroup, 12.9% require revision ACL reconstruction and 18.2% have re-operation. Dr. Murray's team published their two-year data on the BARE procedure. And the basic technical details are listed here in the bullets, but also the figures on the right come from the paper and describe the technique. And briefly, they use a 2.4 millimeter drill with a four and a half millimeter reamer to create the tunnels for the suture and the button that are used, the cortical button. They use number two braided non-absorbable suture. They use a bulbing collagen scaffold that's delivered via medial arthrotomy and autologous blood is injected into the collagen patch. When looking at the demographics for this patient group, mean age for the BARE procedure was 17. The mean age for the ACL reconstruction was 17. So this is being done in a very young cohort. 15 of the 65 patients in the BARE procedure required meniscus repair at the index surgery and 15 and 35 in the ACL reconstruction required meniscus repair at the index surgery. The table six here below shows the data for these patients at follow-up. And you can see the rate of meniscus surgery in this patient group. 12 and a half percent required meniscus surgery with ACL revision in the BARE group compared to just one in the ACL reconstruction group. So it's a little concerning that there may be a higher rate of meniscus injury at subsequent surgery, but that wasn't found to be statistically significant based on the P value less than 0.15. There are potential benefits of repair. Dr. Murray's team has robust preclinical studies demonstrating decreased risk of osteoarthritis when comparing to no repair as well as when comparing to ACL reconstruction. There's no autograft harvest so you can avoid donor site morbidity and this leaves this available for revision if needed. And it may make for a potentially easier revision assuming the menisci and cartilage are intact. However, there are a lot of considerations we have to make when thinking about ACL repair. Are these truly isolated ligamentous injuries or may there be a grade two MCL tear or an anterolateral complex injury that we have to consider? How do we consider repair in the meniscus tear patient group? We've all seen studies that show a higher meniscus repair success rate in patients undergoing concomitant ACL reconstruction. It's not clear if that is gonna be the case with concomitant ACL repair. The tear location is critical for ACL repair. Injury acuity is certainly important to understand before the patient develops increased laxity associated with their ACL deficient knee or perhaps meniscus injuries associated with it. Rehabilitation is typically different for ACL repair versus reconstruction. The historical repair results are certainly gonna influence a lot of surgeons to not pursue this option for patients. We have to understand patient age and their risk for re-tear. Skeletal maturity comes into consideration. Tibial slope was a recent hot topic and a patient with high tibial slope may not be an optimal candidate for repair. The performance of extra articular reconstruction procedures may also be important and their performance with the repair or reconstruction has not been fully evaluated. Exact ACL repair technique remains to be determined and the implants required, whether a scaffold is necessary, is certainly something that needs to be fully evaluated and there are ongoing clinical trials to address this. There may be a lot of surgeons that are in the early majority that are still waiting for this technology to come to the point where they're willing to adapt it. There's certainly some innovators and early adopters considering repair and performing it in select patients, but I think the majority are still waiting to adapt this into their practice until they really have data that supports selecting this technique over reconstruction. So in conclusion, the history reveals that the historical techniques were not viable. Reconstruction, although it has limitations, it remains the gold standard in my opinion and repair needs to be considered with exact details of the procedure. Repair without scaffold has been shown to have a potentially high failure rate in young patients, although larger studies are certainly necessary to confirm these findings. The Bayer procedure definitely has robust preclinical research and promising early clinical results and the ideal candidate and technique for ACL repair remain unknown. Thank you.

Dr. Andrew Gieseland

ACL primary repair

history

reconstruction data

modern repair techniques