Abstract
Background:
Meniscal root tears are radial tears occurring at or within 1 cm of the meniscal root attachment. These injuries have been shown to be the biomechanical equivalent of a total meniscectomy and are thought to be responsible for a rapid progression of osteoarthritis if left untreated.
Indications:
Meniscal root repair is indicated if possible, with the exception of patients who have diffuse Outerbridge 3-4 osteoarthritis of the ipsilateral compartment, those who are poor surgical candidates due to age or medical comorbidity, or in whom nonsymptomatic tears are found incidentally.
Technique Description:
Standard 2-portal arthroscopy is performed. Once a medial root tear has been identified and concomitant pathology has been addressed, we typically begin the repair by trephinating the deep medial collateral ligament with an 18-gauge needle to enhance visualization and avoid iatrogenic cartilage injury. Arthroscopic shaver is used to debride the meniscal root as needed. A meniscal root guide is introduced into the joint and an incision is made on the anteromedial tibia for outside-in drilling of a transosseous tunnel. Drilling is performed with a 5-mm retroreaming device, and a 10-mm socket is created. Nonabsorbable suture is then passed through the meniscus using a self-capture device in an inverted mattress configuration, following by 2 cinch stitches. The sutures are then shuttled into the transosseous tunnel, and the meniscal root is reduced and tensioned in full extension, with the sutures being fixated into a suture anchor on the anteromedial tibia.
Results:
A recent large systematic review of 1086 patients undergoing treatment of meniscal root tear via either debridement or nonoperative management compared with meniscal repair found that conversion to total knee arthroplasty occurred in 11% to 54% of those managed via debridement or nonoperative care versus 0% to 1% for those with root repair.
Discussion/Conclusion:
Currently, meniscal root repair offers the greatest improvement and lowest risk of conversion to arthroplasty following meniscal root tear. The present technique offers a durable repair that we believe combines ease of execution with decreased risk of suture pull-out, by creating a ripstop-type construct. Long-term outcome studies are needed for this and other root repair techniques.
This is a visual representation of the abstract.
Video Transcript
This is a video technique of arthroscopic medial meniscus root repair.
The authors’ disclosures are listed here as well as available online.
Meniscal root tears are known to be an issue related to the development of osteoarthritis in a rapid fashion, and different biomechanical and clinical studies have shown the importance of recognizing and treating these tears.
Anatomically we know that the medial meniscus is a larger C-shaped structure that is less mobile than the lateral meniscus and it functions in 2 regards—one as a decrease in anterior translation of the tibia secondary to the anterior cruciate ligament and the other as distributing forces in the tibiofemoral joint due to circumstantial fibers in the hoop stresses.
Medial meniscal root tears render the meniscus functionally deficient similar to meniscectomy state. This has been shown with multiple biomechanics studies; in particular, with increased knee flexion, a root tear functions the same as a meniscectomy. And this can be restored to native contact forces with the medial meniscal root repair.
These injuries tend to happen through multiple mechanisms, with descending stairs being the most common, as well as kneeling down; feeling a posterior pop in the knee or pain in the back of the knee is common although that is not the primary complaint. Nonoperative management of meniscal root tears as analyzed by Krych et al demonstrates that there is a 31% conversion to total knee arthroplasty at 120 months of follow-up, with most of these happening early in follow-up in the first 2 years. In all, 87% of patients had worsening of their radiographic findings compared with their initial injury films. This negative natural history is important. However, it is unclear which patients we can intervene on and prevent this downhill decline in development of arthritis and pain in progression to arthroplasty.
Surgical indications for medial meniscal root tears include limited arthritis with essentially normal radiographs and having pain with conservative management, which could include an offloading brace and injections, and it is unclear what strict cutoff should include regarding body mass index and alignment. In this example, it is a 61-year-old woman with pain in the right knee for approximately 3 months; she had this with jumping activities and did feel a pop in the knee. On physical examination, she had an effusion with relatively maintained range of motion and tenderness along the medial joint line in otherwise stable examination.
Imaging at that time demonstrated anteroposterior and flexion posteroanterior views that she had no joint space narrowing. She did have 4.5° of varus and had Kellgren-Lawrence grade 0-1 changes, as mentioned. On axial magnetic resonance imaging (MRI), it was clear that she had a tear of the posterior medial meniscal insertion at the root, and looking at coronal views you could see the same disruption, and she had associated extrusion with a ghost sign. Based on these findings, it was concerning that she had several factors that could be related to the pain that she had. Most notable was the medial meniscal root tear; she did have also some varus and no significant arthritis. Based on these findings, we recommended an isolated medial meniscal repair.
Diagnostic arthroscopy first starts with checking the integrity of the remainder of the meniscus, as well as the associated tibial femoral cartilage. A drive-through can be performed to try to evaluate the status of the root which sometimes is completely avulsed; in this setting, there has been some fibrous tissue that did reattach. However, it is functionally deficient based on the MRI. We now place a spinal needle posteromedially first within the joint to confirm its location. We then move it outside the joint just proximal to the joint line at the medial collateral ligament (MCL) and attachment on the femur, performing percutaneous trephination while applying valgus stress.
This allows significant opening of the medial tibial femoral joint, improving the diagnosis of that tear as well as the treatment. We then place a flexible cannula in the anterior medial portal that was spinal needle localized from before and then plan to prepare the area for the meniscus root repair. This is done initially with a shaver, and the shaver is utilized to debride any remaining tissue that is nonfunctional in nature. Here, we can see that this debrides very quickly, as this patient did have a complete tear that had some scar tissue that had formed in attempts to heal the repair.
After this fibrous tissue has been removed, we can now see the native insertion of the medial root, as well as the edge of healthy tissue for repair. We then use this over-the-top guide typically set at 5 mm to place our retroreamer, which should exit just adjacent to the medial meniscal root insertion. The goal is to have this under meniscal tissue so that we are not pulling the sutures over to the native insertion but rather pulling the medial edge of the medial root down to our tunnel, which results in its edge reopposing the native insertion. This allows for more surface area contact of the meniscal root with the underlying tunnel to improve overall healing. Here, we are using a flip-cutting reamer to create a 10-mm depth socket. After this is created adjacent to the native root, we use a shaver to debride this debris, including the cartilage and bone from the reaming. This is also what we used for the preparation of the footprint for healing, and here we can see its placement relative to the native insertion in the remaining meniscal tissue.
We then start our repair using an O nonabsorbable suture passed from inferior to superior. We then retract this limb and pass the same limb again with the device inverted from superior to inferior, typically using the tibial tunnel as a recipient site for the needle to allow for full suture passage. We then pull the remaining free ends, which results in a horizontal mattress configuration, taking care that these are slightly medial to our tunnels, so we reduce the meniscus. We then pass a luggage tag configuration stitch in a ripstop manner just posterior to the prior mattress suture. After this is shuttled through, we can see this opposed to the end of the meniscal tissue, and we place a second luggage tag stitch medial to this, so we have a total of 4 suture ends.
We then place a passing stitch through the meniscal tunnel, which is then retrieved through the same cannula where the remaining sutures are placed. This will allow for shuttling of all of the sutures without any issues in decreasing the chance of there being a soft tissue bridge during suture passing. These sutures are then passed outside of the body through a knotless PEEK interference anchor. After these are placed, we then drill the anterior medial cortex with a pilot hole, followed by the tap for the associated anchor. This 4.75-mm PEEK anchor is then malleted into place, and we then set the tension individually for each suture again under direct visualization. Here, we can see the insertion of the anchor into the anterior medial cortex and then we will set tension of the horizontal mattress suture, which is relatively posterior, followed by the anterior luggage tag sutures, giving full compression from front to back of the entirety of the repair. This is done with the knee in full extension to make sure that there is no over-advancement of the posterior meniscal capsule if being performed at 90° of knee flexion.
Laprade et al evaluated the biomechanical consequences of nonanatomical root repairs, finding that repairs that were not within 5 mm of the native root demonstrated worse contact pressures compared with those performed within 5 mm. Individual patient selection should be taken into account based on the mobility and tissue quality, and medialization of the tunnel is appropriate if the mobility of the tissue is poor. Looking at the release of the medial collateral ligament, there are 2 studies that have evaluated this. This one demonstrates a distal release superficially with associated postoperative repair. Deep MCL release through spinal needle trephination has also been shown to be successful with no significant rate of postoperative symptomatic MCL laxity. Looking at different root repair constructs, Anz et al evaluated stitch configuration. Most of the studies that have looked at this factor show that the configuration does play a role; the more sutures you have, the more likely you are to have more normal restoration of pull-out forces. Again, looking at specific stitch configurations, the loop stitch tends to be one of the strongest and most stiff configurations, but in this setting, none were similar to native forces. In our example, we did use 2 loop stitches as well as a mattress stitch to try to get as much footprint coverage as possible.
Postoperatively, the patient is placed in a long leg brace as the quad is usually inactivated, as well as to protect the MCL during that time. We limit weightbearing to nonweightbearing or toe touch depending on what the patient can tolerate during the first 6 weeks, and motion is from 0° to 90°. After 6 weeks, we discontinue the brace, advance weightbearing as tolerated, and advance to full range of motion. After 3 months, we start ramping up activity as tolerated.
When we look at the outcomes of arthroscopic debridement of root tears versus repair, it is clear that the nonoperative treatment is similar to debridement, and therefore if you are operating it is difficult to justify debridement as opposed to repair. When looking at repair compared with meniscectomy directly, repair had better patient-reported outcomes, including Lysholm and International Knee Documentation Committee scores, less progression of arthritis on radiographs, and significantly less conversion to total knee arthroplasty.
Looking at MRI outcomes relative to clinical outcomes after repair, all patients improved regardless of the amount of extrusion that they had on MRI. And MRI showed advancement of cartilage damage when radiographs remain stable; it may be a more sensitive indicator of progression of disease.
Another study looking at outcomes by Kim et al demonstrated that all patients improve regardless of the amount of extrusion they had and that decreased extrusion also correlates with less chance of advancement of radiographic disease as well as further improved clinical outcomes.
References for this talk can be found here.
Thank you very much for your attention.
Footnotes
Submitted June 14, 2021; accepted June 30, 2021.
One or more of the authors has declared the following potential conflict of interest or source of funding: A.B.Y. received personal fees from CONMED Linvatec, JRF Ortho, and Olympus; received grants from Aastrom Biosciences, Arthrex, Organogenesis, and Vericel; received nonfinancial support from Smith & Nephew and Sparta Biomedical; and received nonfinancial support and stock or stock options from Patient IQ. S.F.D. received hospitality fees from Medical Device Business Services and Zimmer Biomet Holdings; received education fees from DePuy Synthes Sales and Zimmer Biomet Holdings; and is a board or committee member of American Academy of Orthopaedic Surgeons. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
