Hi, my name is Adam Yenke from Rush University and I'm talking on medial meniscal root tears in a recent update. I'd like to start with a case presentation with a 55-year-old male who had posterior knee pain, swelling, and two popping episodes after a flexion rotation incident. This MRI from February of 2017 was prior to his popping episodes. We can see bone marrow signal at the posterior medial root insertion, and here we can see an MRI one month later where he has a complete avulsion of his posterior medial root that is traumatic in nature with the preclinical degenerative changes that likely led to this structural failure. In general, the epidemiology would suggest that medial meniscal root tears are in older patients less likely associated with an ACL and also more likely to be associated with arthritis at the time of diagnosis. Looking at the injury patterns with medial meniscal root tears, it's actually most of patients are descending stairs, and a hyperflexion injury is less likely to be the case, even though anecdotally that's a very common complaint, and having a pop in the back of the knee is also typically associated with these tears. The reason these tears are such an issue is that the medial meniscus is not mobile. It's firmly anchored into the posterior and anterior root, as well as in the peripheral meniscal tibial ligaments. These factors, including the circumferential fibers that provide the hoop stress that prevent extrusion of the meniscus, are functioning until a root tear is present, in which case these are completely disrupted. This essentially makes the meniscus completely non-functional, similar to a meniscectomized state. It's fairly clear, based on multiple studies, that performing a meniscal repair can help restore normal joint forces to those of a native knee with an intact meniscus. This is an example of a patient who complained of medial joint line pain. They did not have any further evaluation. They then presented a year later for continued pain. X-rays demonstrated complete collapse without osteophyte formation. One year later, this is indicative of a medial meniscal root tear, and where there's catastrophic failure of that area of the joint, where there's not time for long-term arthritis to set in, this is structural failure from increased pressure seen in that area. The key with root tears is to see them before they see you, to make sure that you don't miss out on them, and to catch the horse before it gets out of the barn, because once it's too late and arthritis is set in, it's fairly clear that there's no good intervention other than a knee replacement. When looking at the literature, non-operative management of root tears has approximately a 30% conversion of total knee arthroplasty, and almost all patients progress with regards to radiographic changes. So there is a clear negative history, but how do we figure out who we can help with a repair, and is there a role for a debridement? Looking at work by Aaron Critch, we know that a debridement does not offer any benefit over the natural history of non-operative treatment with regards to symptomatic or radiographic outcomes. So if operating, it's hard to justify a debridement. So again, in these patients with an acute post-remedial root tear, or at least someone who has a root tear without any advancement of arthritis, what is the best recommended treatment? We still will do frequently steroid injections, anti-inflammatories, offloading braces, sometimes crutches or physical therapy, however there's no evidence to guide these decisions and it should be made on a case-by-case basis. Medical indications can include clear evidence of a root tear and MRI, with or without extrusion, Kellgren-Lawrence grade 2 or less arthritis, continued pain, and it's hard to know if there are any strict cut-offs for BMI or alignment, but they're clearly related to outcomes and failure of the meniscal root repair. When we look at clinical and radiological results of medial root repair versus meniscectomy, root repair did have better PRO outcomes, less radiographic progression of arthritis, and a conversion rate of 0% to total knee versus 35% of patients treated non-operatively, or with meniscectomy rather. When we look at extrusion associated with outcomes of root repair, all patients improved regardless of the amount of extrusion, MRIs showed advancement of cartilage damage, and this did not present itself on the radiographs, however, and the MRIs were more sensitive. When looking at extrusion associated with clinical outcomes, again, Kim et al. evaluated this and demonstrated that all patients improved, again, regardless of the amount of extrusion, however, less extrusion correlated with less radiographic advancement and also further improved clinical outcomes, similar to the findings of the prior paper. When looking at the effect of outcome based on BMI, age, and alignment, it did appear that there was no significant effect with BMI and age on the outcomes of root repair, however, alignment worse than 5 degrees of varus was negatively associated with the overall clinical outcome. Biomechanical technique has multiple variables that should be considered, whether it's transosseous fixation versus an anchor, the suture configurations, tunnel location, how you release the MCL or provide access, whether or not you perform biologic augmentation, what you do with your post-operative protocol. We know that the biomechanical consequences of a non-anatomic repair is significant in that a repair that's not within 5 millimeters of the native root does not restore native contact forces, however, you should evaluate the mobility of the medial meniscal root based on the patient-specific situation and provide a tunnel that is still under the meniscus to allow for healing as you cannot pull a meniscus to the native root that has segmental tissue loss. With regards to releasing the MCL, this study by Kim et al. looked at a superficial distal MCL release with a repair and found that there was no significant issues related to chronic MCL laxity. In our practice, we perform a proximal deep MCL trephination with a spinal needle, which has also been demonstrated to not affect clinical outcomes negatively. When looking at different root repair constructs, it's clear that suture and stitch configuration matters and the amount of stitches matters as well, with more stitches being better than less stitches. When we look at the stitch configuration, a loop stitch by Matava et al. was stronger than any other configuration, however, it did not restore the native forces. Our preferred treatment is two loop stitches plus a horizontal mattress stitch to try to provide as much footprint restoration as possible and native tissue strength as possible as well so that the sutures do not pull out of the tissue. Here's an example of a diagnostic arthroscopy where we don't see any significant arthritis. The meniscus body itself looks relatively healthy. We see that there may be some abnormalities of the root, but we're really relying on the MRI at this stage. We perform a debridement and try to visualize, and now we can see that as we lift the root, there is no bony attachment of the root whatsoever, and this is a clear, complete medial meniscal root tear. We then release the deep MCL using a spinal needle, trephinating through the proximal deep MCL. This significantly improves our visualization and allows for more complete debridement of the root. After this has been complete, we can then use our medial root guide, typically set at five or 7.5 millimeters off of a posterior offset. This is placed just adjacent to the native root insertion, typically not at the native insertion itself, as we would like to bring the tissue down on top of the tunnel. We then use this retro reamer where we can flip the blade and provide a socket for the tissue to be overlaid on top of. We do not use a curette to debride this area when we use this flip cutting device. However, if a two-tunnel technique is used, a curette is usually preferable. After this is complete, we debride this aperture. We then prepare for suture passage. Again, a motorized rasp or a curette can be utilized to improve the overall footprint bleeding area for increased surface area for healing. Sutures can be passed in a variety of configurations. We prefer passing a posterior horizontal mattress stitch configuration, going from inferior to superior and superior to inferior, passing into the tunnel so there's increased extrusion of the needle is provided by allowing it to go into that tunnel. After we do that, we place typically two luggage tag stitches. In this scenario, one stitch was passed, followed by a second for a total of four suture limbs that will come through the tunnel. We then place a passing suture to allow us to shuttle these sutures, typically through a cannula to prevent a soft tissue bridge in the anterior medial portal. When these are reduced, we can see that there is reduction of the medial end of the meniscus to its native insertion. Here we can see pulling the horizontal mattress suture, followed by pulling the anterior sutures, and you can see how pulling both of the sutures really provides a much better apposition to the tunnel and doesn't just pull the front of the meniscus down. Here's another example of performing a reduction of a meniscus, and in this situation there's a single luggage tag suture that is utilized, and the front is pulled down by the luggage tag, and the horizontal mattress pulls down the posterior aspect. After the repair is complete, the patient is placed in a long leg brace to protect the MCL for six weeks. We also limit weight bearing for the first six weeks, as well as flexion past 90 degrees. After that, we get rid of the brace, advanced weight bearing is tolerated, and work on full range of motion. After three months, we then release the patient to all activity as tolerated, typically taking another one to two months to really reach normal activity levels. In summary, there's decreased likelihood of success of meniscal root repair if there's already advanced arthritis occurring prior to surgery. It's unclear if there's a benefit of high tibial osteotomy plus root repair versus a root alone, though if alignment is worse than five degrees, there is a consideration. Decreased extrusion is ideal for MRI and clinical outcomes, as well as decreased progression of radiographic arthritis, and there's no current evidence for root debridement. Thank you very much. We appreciate your time.

Adam Yenke

Rush University

medial meniscal root tears

posterior knee pain

treatment options