Abstract
Background:
Meniscal root tears typically result from a hyperflexion/squatting injury or are in conjunction with ligamentous knee injury. Once a complete tear occurs, the meniscus is unable to convert axial loads to transverse hoop stresses which result in increased tibiofemoral contact pressure and osteoarthritis. The goal of a meniscal root repair is to anatomically reattach the meniscal root to the tibia plateau. Complete and partial healing occurs in over 93% of cases with retear rates ranging from 0% to 7%.
Indications:
We present a case of a highly active 21-year-old male collegiate soccer play that sustained a medial meniscal root tear after slipping on ice.
Technique:
An anatomic medial meniscal root repair was performed using a transtibial guide and 2 loop sutures tied over a button.
Results:
Full anatomic footprint coverage was able to be achieved intraoperatively and gentle range of motion from 0 to 90° of flexion did not result in gap formation.
Discussion/Conclusion:
Successful outcomes with full anatomic footprint coverage of the medial meniscal root can be achieved with 2-loop suture button configuration.
This is a visual representation of the abstract.
Video Transcript
Meniscus Root Repair presented by Dr John Matthews and co-authors Ryan Paul and Dr Sommer Hammoud.
None of the authors have a disclosure to mention.
The menisci are crescent-shaped fibroelastic cartilage that function to optimize force transmission across the knee. This is accomplished through increasing joint congruency and providing shock absorption during axial loads. The posterior horn of the medial meniscus also provides secondary stabilization preventing anterior tibial translation. The menisci receive their blood supply at the peripheral margins through the genicular arteries.
The anterior and posterior roots of each menisci are anchored to the tibia plateau. Prior studies have demonstrated that posterior root tears result in altered tibiofemoral contact mechanics and inability to convert axial load to transverse hoop stresses. Root tears can result in meniscal extrusion, increased cartilage loss, as well as osteophyte formation. Biomechanically, studies have demonstrated that a root tear increases the peak local contact stress in the tibiofemoral joint by 235%, equal to a total meniscectomy.
Meniscal root tears can occur with hyperflexion injuries such as squatting or in conjunction with ligamentous knee trauma. Degenerate tears are commonly encountered in patients between 45 and 60 years old. The posterior root of the medial meniscus has the highest incidence of tears, because it is the least mobile. When tears do occur, type 2, complete radial tears, are the most common.
Clinically, patients may report a “pop” with associated swelling and pain along the posterior aspect of the knee, especially in higher degrees of knee flexion. Patients may also report occasional locking or giving away of the knee.
On examination, it is important to inspect the limb alignment and the presence of an effusion. Patients may report joint line tenderness consistent with meniscal pathology, especially posteriorly as well as pain in deep flexion passed 90°. Knee range of motion (ROM) and neurologic status should be documented. A thorough ligamentous examination should be performed. In addition, there are several provocative maneuvers described to evaluate meniscal pathology, such as the Apley, Thessaly, and McMurray tests.
X-rays should be obtained to evaluate for associated fractures, avulsions, and the presence of osteoarthritis. The presence of advanced arthritis has been associated with poor outcomes following meniscus root repairs. A magnetic resonance imaging (MRI) is considered gold standard and may reveal a ghost sign which is demonstrated on the T2 sagittal cut on the superior image. This represents a missing posterior root along posterior tibia plateau, as well as meniscal extrusion, which is seen on the bottom T1 coronal view.
Once a meniscal root tear is diagnosed, nonoperative treatment includes antiinflammatory medications, physical therapy, and injections. These should be considered in older/low demand patients, as well as those with advanced arthritis. Operative indications include acute tears in the younger population and those that have failed conservative management.
For this case, the patient was an active 21-year-old male collegiate soccer player who sustained a hyperflexion injury to his knee after slipping on ice.
On examination, he was 5′11, 165 pounds. Visual inspection of the knee demonstrated 2+ effusion with posterior medial joint line tenderness. He had full passive ROM although reported discomfort with hyperflexion. His knee was stable to ligamentous examination and neurovascularly intact.
Plain radiographs were obtained and did not demonstrate any osseous abnormality with well-maintained joint space.
A coronal T2 MRI demonstrated a complete radial tear along the posterior horn just medial to the root with extrusion and a small stump of root remaining attached to the tibia plateau. On the T2 sagittal view, there was small bony contusion along the posterior medial tibia plateau. These are marked by the red arrows.
Surgical intervention was recommended for this patient due to his age, activity level, and tear configuration.
The patient was taken to the operating room and positioned supine with a leg holder to perform a knee arthroscopy. Standard vertical medial and lateral portals were used along the patellar tendon. After a diagnostic arthroscopy was performed of the adjacent compartments, the medial compartment was visualized which did not demonstrate any chondral injury.
A valgus force was applied to the limb for easier access and visualization of the posterior aspect of the medial compartment. This demonstrated a tear along the posterior horn.
For better identification of the tear pattern, a probe was used. The radial tear adjacent to the meniscal root was noted to extend to the capsule and a small stump of meniscal root tissue remained attached to the associated tibia plateau. If visualization of the posterior root is difficult to perform, one tip to consider is pie-crusting of the deep medial collateral ligament fibers to allow easier access to address the pathology.
A shaver was subsequently inserted into the medial compartment to resect the stump of remaining meniscal root tissue. One tip to reach the posterior medial meniscal root tissue is to provide a valgus force with the knee in 20 to 30° of flexion.
Post resection, the anatomic meniscal root attachment site was easily identified. Adequate visualization is key to drilling through the anatomic footprint and allowing for anatomic healing and restoring meniscal function.
The arthroscopic camera was then placed in the medial portal and a transtibial drill guide through the lateral portal. The drill guide was positioned over the medial tibial spine at the medial margin of the anatomic foot print. Once the proper placement was obtained, a skin incision is made and the flip cutter drill bit advanced until it penetrated the tibia surface with the goal being along the medial margin of the footprint, as opposed to the center, since a small amount of root tissue was resected, and we did not want to over tension the posterior horn. Occasionally, the drill bit is under the meniscal tissue and not easily identified, one tip to consider is the tactile feel, and the use of a probe to elevate the meniscus and visualize the drill bit tip.
The probe can also be used to protect the meniscal tissue and posterior capsular prior to flipping the flip cutter and drilling the anatomic footprint. As you can see, this is done in the video here.
The camera is then returned to the lateral portal to allow for retrieval of the passing suture through the medial portal. One tip to find the proper trajectory and hole for the passing suture is to mallet the external guide sheath into the anterior tibial cortex prior to removal of the flip cutter. This allows for easier trajectory and management of the fiber stick.
A self-retrieving passer was then inserted in the medial portal with a loop suture. When passing through the meniscus, it is important to visualize the end of the tear to ensure the suture has adequate surrounding tissue and does not pull out. We prefer using 2 loop sutures placed adjacent to one another. Once the first suture is passed, a gentle tug is performed to ensure it does not pull through the meniscal tissue. The process is repeated for the second suture.
Once again, a gentle tug is performed to ensure the second suture also does not pull through the meniscal tissue.
Once all the sutures are exiting through the medial portal, there are several options to prevent a suture bridge, such as the use of a cannula. For cost purposes and ease, we prefer to run a suture retriever down the passing suture into the medial compartment and then grasping the remaining 2 meniscal sutures prior to pulling the instrument out which ensures all the sutures are traveling in the same tract.
After this is performed, the 2 meniscal sutures are looped into the passing white suture outside the body and pulled through. If a suture bridge is encountered, one tip to consider is gently using electrocautery to free the sutures without damaging the suture material itself. It is important to directly visualize the quality of the reduction at this stage to ensure an anatomic repair.
The blue sutures are then placed over a button which is tensioned along the anterior/lateral tibial cortex and tied. It is important to visualize the reduction prior to locking the knots to ensure the reduction is maintained. The final repair is demonstrated in this picture.
Postoperatively, the patient is placed in a ROM knee brace unlocked from 0 to 90° for the first 6 weeks and made toe-touch weight bearing. Full weight bearing at 8 weeks. Running is allowed after 4 months and typical return to sport is at 6 months.
Postoperative outcomes have demonstrated favorable results with meniscal root repairs. Kim et al also demonstrated root repairs outperform partial meniscectomies with regard to patient-reported outcomes, as well as radiographic outcomes, demonstrating less joint space narrowing and progression of arthritis. There is a 93% rate of complete or partial healing with retear rates ranging from 0% to 7%. It is important to be cognizant of the posterior neurovascular structures when drilling the tibia tunnel to prevent injury.
These are the references.
Thank you.
Footnotes
Submitted July 2, 2021; accepted August 11, 2021.
The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. 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.
