Techniques for Improving Visualization for Medial Meniscus Posterior Root Repair

Abstract

Meniscal roots are critical components of the menisci that ensure joint congruity and allow the meniscus to serve its biomechanical function of converting axial loads into hoop stresses. Repairing the meniscal root is critical to prevent accelerated knee joint damage and progression to osteoarthritis, but access to the posterior roots, in particular, can be challenging. Regardless of the technique utilized, adequate visualization and access to the posterior roots is critical to perform an appropriate repair. While percutaneous release of the medial collateral ligament has been demonstrated in previous technical notes and has been shown not to negatively affect outcomes for patients, other methods for improving access and visualization to the posterior knee, such as performing a reverse notchplasty, or a resection of the medial tibial spine are also useful techniques. In this technical note, we present the senior author's combined techniques for improving visualization of the posterior meniscal root when performing a medial meniscus posterior root repair.

The anterior and posterior meniscal roots are critical components of the menisci, which ensure joint congruity and stability within the tibiofemoral joint.¹ The roots anchor the meniscus, preventing extrusion and allowing it to serve its biomechanical function in converting axial loads into hoop stresses.^1,2 Removal of these hoop stresses leads to increased medial compartment contact pressures, lateral tibial translation, and progressive joint degeneration, similar to a total meniscectomy.3, 4, 5 To alleviate pain, restore native joint biomechanics, and prevent early-onset osteoarthritis (OA) of the knee, arthroscopic root repair is recommended in appropriately indicated patients.^1,6, 7, 8, 9

Arthroscopic techniques for repairing meniscal root tears are primarily divided into 2 categories: trans-osseous suture repair and all-inside suture anchor repair.^10,11 Regardless of the technique, repairing the posterior medial meniscal root can be particularly challenging due to limited visualization and restricted access to the root. To improve visualization, several techniques to percutaneously release the medial collateral ligament (MCL) have been described as an effective method to open the medial knee joint.^5,7,12 Other less commonly discussed methods for improving visualization and access to the posterior root include performing a resection of a portion of the medial tibial spine and a reverse notchplasty of the posterolateral aspect of the medial femoral condyle.⁴ The purpose of this technical note is to describe the intraoperative considerations and technique of all 3 methods in combination to improve access and visualization during medial meniscus posterior root (MMPR).

Surgical Technique

Patient Preparation and Diagnostic Arthroscopy

The patient is placed in the supine position on the operating table. Following placement of a nonsterile tourniquet on the thigh, the patient's lower extremity is prepped and draped in the usual sterile fashion. A standard diagnostic arthroscopy is performed by first establishing the anterolateral (AL) portal. An arthroscope is introduced into the AL portal, followed by an outside-in technique with a spinal needle to establish the anteromedial (AM) portal. A probe is then inserted into the AM portal to assess the knee joint for other possible meniscal, ligamentous, or chondral pathology.

Techniques to Enhance Posterior Visualization of the MMPR

MCL Trephination

To increase access to the posterior aspect of the medial compartment, percutaneous trephination of the MCL can be employed.⁵ A spinal needle is introduced 1-2 cm distal to the medial epicondyle and 1-2 cm proximal to the joint line (Fig 1). Aiming distal and deep into the knee joint, the needle enters just proximal/superior to the posterior medial meniscus. With the knee positioned in ∼20° flexion under a gentle valgus load, the needle is then retracted from the joint but kept subcutaneous and trephinated back and forth into the proximal MCL. This technique, commonly referred to as pie-crusting, increases the medial joint space clearance by 2-4 mm, facilitating improved arthroscopic visualization and instrument maneuverability throughout the medial compartment¹³ (Fig 2). Pearls and Pitfalls of this technique are described further in Table 1.

Fig 1.

Percutaneous medial collateral ligament (MCL) trephination to expand the medial compartment. Intraoperative photograph of a left knee with the patient in the supine position, demonstrating percutaneous trephination of the MCL to increase access to the medial compartment. The knee is flexed to ∼20° with a valgus force applied. An 18-gauge spinal needle (A) is inserted using an outside-in approach, aiming distal and deep into the joint. Entry point, denoted by the letter M, is the “magic point” just 1-2 cm distal to the medial epicondyle at the femoral side of the proximal MCL, with the needle placed proximal to the junction of the posterior horn and body of the medial meniscus. Controlled trephination in this location facilitates ligamentous release, increasing the medial joint space by ∼2-3 mm. This maneuver improves arthroscopic visualization and instrumentation for medial meniscus posterior root repair. The dashed line marks the medial joint line, and the medial epicondyle is denoted by the letter “M” for orientation.

Fig 2.

Arthroscopic visualization before and after percutaneous medial collateral ligament (MCL) trephination. Side-by-side arthroscopic images of the left knee, with the patient in the supine position, viewed from the anterolateral portal using a 30° arthroscope. The knee is flexed to approximately 90° in both images. (A) Pretrephination: Prior to MCL release, the medial compartment provides minimal room for maneuverability of instruments and assessment of the medial meniscus posterior root. The medial femoral condyle (A) and medial tibial plateau (B) crowd the visual field, limiting posterior access. (B) Post-trephination: Following percutaneous release of the medial collateral ligament, visualization of the posteromedial compartment is significantly improved. The medial femoral condyle (A), medial tibial plateau (B), and posterior root of the medial meniscus (C) are clearly visible, with an estimated increase in medial joint space clearance of ∼2-4 mm. This expanded space enhances both arthroscopic visualization and safe passage of surgical instruments during posterior root repair.

Table 1.

Pearls and Pitfalls of MCL Trephination

Pearls	Pitfalls
Trephinate only the amount required for adequate visualization.	Overaggressive trephination risks valgus instability.
With a slight valgus load, ensure the knee remains at 20° of flexion.	A knee not kept at 20° flexion may not accurately demonstrate the slow release of the MCL and can risks excessive trephination.
Trephination should occur at proximal 1/3 of MCL near the femoral insertion due to better healing potential.	Suboptimal needle angulation may risk iatrogenic cartilage injury to the femoral condyle or persistent valgus instability.

MCL, medial collateral ligament.

Reverse Notchplasty

For further posterior visualization, a reverse notchplasty may be performed. Using a radio frequency ablation device and motorized oscillating shaver (Arthrex, Naples, FL) through the AM portal, the procedure begins with debridement of the medial aspect of the posterior cruciate ligament (PCL) synovium to expose the posterior intercondylar notch and adjacent medial femoral condyle. Subsequently, the shaver is used to remove a small portion of the posterior aspect of the medial femoral condyle, targeting only the nonweight bearing area of the posterior condyle. This technique creates a broader visual corridor from the AL portal to the medial meniscal root, facilitating accurate root identification and instrument passage during repair (Fig 3). Pearls and Pitfalls are further discussed in Table 2.

Fig 3.

Arthroscopic visualization before and after reverse notchplasty. Side-by-side arthroscopic images of a left knee in the supine position, viewed with a 30° arthroscope through the anteromedial portal with the knee flexed to 90°. (A) Prenotchplasty: Prior to bony resection, the medial femoral condyle (A) obstructs visualization of the posterior joint space, limiting access to the posterior root of the medial meniscus. The medial tibial plateau is labeled (B). The red outline demarcates the non-weightbearing posterior margin of the medial femoral condyle that is targeted for resection to improve access. (B) Postnotchplasty: Following reverse notchplasty, a small portion of the posterior aspect of the medial femoral condyle (A) has been resected. This allows for improved exposure of the posterior root of the medial meniscus (C). A radiofrequency ablation probe (D) is introduced through the anterolateral portal to assist in synovial and bony debridement. The medial tibial plateau (B) remains in view. This technique provides a wider visual corridor to the posterior horn, enhancing both visualization and instrumentation for meniscal root repair.

Table 2.

Pearls and Pitfalls of Femoral Reverse Notchplasty

Pearls	Pitfalls
Ensure the shaver is maintained on the posteromedial aspect of notch without significant violation of articular cartilage.	Overaggressive debridement can risk iatrogenic injury to weight-bearing portion of the knee.
Stay on the medial and posterior to the PCL margins.	Ablating too anterior or lateral may cause iatrogenic injury to the PCL or alter knee biomechanics.

PCL, posterior cruciate ligament.

Medial Tibial Eminence Resection

The medial tibial eminence can be selectively resected to provide a more direct line of sight to the MMPR. Using a motorized shaver through the AM portal, cartilage and bone are resected from the medial aspect of the tibial eminence (Fig 4). Care is taken to avoid injury to the adjacent anterior cruciate ligament (ACL) insertion, which lies more laterally. This maneuver also improves seating of the transtibial root guide by eliminating interference from the native upsloping morphology of the eminence. In addition to improving visualization, this technique induces cancellous bone bleeding, which may enhance the biologic environment for root healing. Pearls and pitfalls are further discussed in Table 3.

Fig 4.

Arthroscopic visualization before and after medial tibial spine resection. Side-by-side arthroscopic images of a left knee in the supine position with the knee flexed to 90°, viewed using a 30° arthroscope from the anteromedial portal. (A) Preresection: Prior to resection, the upsloping medial tibial spine (E, outlined in red) impinges on the visual field and obstructs instrument access to the posterior root of the medial meniscus (C). The medial femoral condyle (A), medial tibial plateau (B), and a radiofrequency ablation probe (D), introduced through the anterolateral portal, are also visible. The elevated profile of the medial tibial eminence limits guide positioning and restricts surgical maneuverability. (B) Postresection: Following controlled removal of the medial tibial spine (E), an unobstructed view of the posterior root of the medial meniscus (C) is obtained. The resection creates a flatter working surface, allowing easier placement of drill guides and improved visualization for root repair. A probe (D) introduced through the anterolateral portal confirms access and positioning. The medial femoral condyle (A) and tibial plateau (B) are again shown for orientation.

Table 3.

Pearls and Pitfalls of Medial Tibial Eminence Resection

Pearls	Pitfalls
Stay on the medial aspect of the tibial eminence	Resecting too laterally poses risk to the ACL insertion.
	Over-resection may compromise bone integrity.

ACL, anterior cruciate ligament.

MMPR Repair

Once visualization is optimized, the MMPR is inspected. The senior author's preferred technique for MMPR repair involves a transtibial tunnel approach with a subchondral, knotless, adjustable implant (SutureLock; Arthrex), which will be briefly described in the following sections.⁴

Root Preparation

To promote vascular ingrowth and optimize healing potential, the torn edge of the MMPR is debrided, and the bony root attachment site on the tibial plateau is decorticated using a ring curette to expose bleeding cancellous bone. In cases of chronic meniscal extrusion, the peripheral meniscotibial attachments may be carefully released to mobilize the root and enable accurate anatomic reduction. On the basis of surgeon discretion and patient pathology, centralization sutures may also be placed at this time to help reduce meniscal extrusion, improve stability, and restore hoop tension along the periphery of the meniscus.

Transtibial Tunnel Drilling

A tibial drill guide is introduced through the AM portal and positioned at the native footprint of the posterior root. The guide is then directed toward the AM tibial cortex, and a small skin incision is made to accommodate the tibial guide sleeve. A 2.4-mm cannulated guide pin is advanced through the sleeve and into the joint, exiting at the root's insertion site. After removing the inner trocar, a nitinol suture wire is passed through the cannulated pin and retrieved from the AM portal for subsequent shuttle of the repair device.

Implant Passage and Fixation

The all-suture implant is delivered in a retrograde fashion through the tibial tunnel using the shuttle wire and seated beneath the tibial cortex to provide aperture fixation at the root attachment site. Secure seating of the implant is confirmed arthroscopically and by ensuring resistance to pullback. A clamp is then placed on the sutures at the tibial exit site to maintain tension during the repair. The two number 2 repair sutures from the SutureLock implant are then transferred from the AM to the AL portal.

Suture Passage and Repair

An 8-mm cannula (PassPort; Arthrex) is placed in the AM portal to prevent soft tissue interposition. The blue repair suture is retrieved out of the AL portal and passed into the root using a self-retrieving suture passer (Knee Scorpion; Arthrex). Working from posterior to anterior, an inverted horizontal mattress rip-stop suture is placed. This is followed by placing the second white repair stitch more medial to the horizontal mattress suture in a simple vertical fashion to create a modified Mason–Allen suture configuration.¹⁴ Each repair suture is sequentially shuttled back through the tibial tunnel. Alternating tension is applied to the blue and white sutures to gradually reduce the meniscal root to its native tibial footprint. The knee is then gently cycled through a range of motion from 0 to 80° of flexion to assess repair stability and graft tracking. Final tensioning is performed with the knee held at approximately 80° of flexion to optimize meniscal apposition (Fig 5). Under direct arthroscopic visualization, the repair is confirmed to be anatomic and secure. The suture limbs are then trimmed flush at the tibial cortex to complete the fixation.

Fig 5.

Completed medial meniscus posterior root repair. Arthroscopic image of a left knee in the supine position with the knee flexed to 80°, as viewed through the anteromedial portal using a 30° arthroscope. The medial femoral condyle (A), medial tibial plateau (B), and posterior root of the medial meniscus (C) are clearly visualized. A blue suture from the previously placed inverted horizontal mattress stitch is seen securing the medial meniscus root to its anatomic tibial footprint. This suture is part of a modified Mason–Allen configuration, which combines a rip-stop horizontal mattress stitch with a vertical simple suture passed more medially (not seen). Following passage, each repair suture was sequentially shuttled through the tibial tunnel, and alternating tension was applied to ensure controlled reduction of the root to bone. Final tensioning was performed at 80° of knee flexion to optimize root compression and footprint contact. The final construct demonstrates stable, anatomic root fixation under direct arthroscopic visualization.

The techniques noted above are demonstrated in Video 1.

Discussion

While transtibial repair is widely accepted as the gold standard for addressing MMPR tears, one ongoing challenge remains in achieving adequate visualization of the anatomic insertion site. Limited access to the posteromedial compartment frequently necessitates adjunctive techniques to widen the medial joint space, which improves tunnel trajectory, facilitates anatomic root placement, and reduces the risk of iatrogenic cartilage injury.¹⁵ Although percutaneous release of the MCL has been well described, there is limited technical guidance in the literature regarding the use of reverse notchplasty or medial tibial spine resection to improve access to the MMPR. This technical note demonstrates the combination of 3 commonly used visualization-enhancing strategies: MCL trephination, limited resection of the medial tibial spine, and medial condyle reverse notchplasty.

The safety and efficacy of percutaneous MCL trephination have been established in prior investigations. Moran et al. conducted a systematic review, including 234 knees undergoing MCL release and found no significant short- or long-term complications, including valgus instability, persistent pain, or neurovascular injury.¹⁵ While the safety profile of MCL release is well supported, there remains a paucity of literature examining the technical nuances, indications, and outcomes associated with reverse notchplasty and medial tibial spine resection. Overall pearls and pitfalls are discussed in Table 4.

Table 4.

Advantages and Disadvantages of Utilizing MMPR Visualization Techniques

Advantages	Disadvantages
Increases medial joint space by 2-4 mm, improving visualization, which also decreases iatrogenic articular cartilage injury	Iatrogenic grade 2 MCL strain is created to open the medial joint space.
Broadens visual corridor to the posterior medial root	Risk of iatrogenic injury to the ACL and PCL
Targets nonweight bearing portion of the femoral condyle	Overaggressive debridement risks iatrogenic cartilage damage to the weight-bearing portion of the knee.

ACL, anterior cruciate ligament; MCL: medial collateral ligament; PCL, posterior cruciate ligament.

The clinical and biomechanical importance of restoring the meniscal root to its native footprint has been well documented. Multiple studies have shown that anatomic repair results in more favorable load distribution across the tibiofemoral joint and reduces the progression to osteoarthritis compared to nonoperative treatment or partial meniscectomy.^1,7,8,16,17 Additionally, the long-term economic value of root repair has been demonstrated. In a meta-analysis and cost-effectiveness study, Faucett et al. reported that posterior root repair significantly lowered the likelihood of requiring total knee arthroplasty (TKA), leading to reduced overall health care expenditures.

Integrating adjunctive techniques, such as reverse notchplasty and medial tibial spine resection, in combination with MCL trephination, when necessary, allows surgeons to optimize access and visualization of the posterior root footprint. These methods may enhance surgical precision and reproducibility, reduce intraoperative risk, and ultimately improve clinical outcomes in patients undergoing transtibial MMPR repair.

Disclosures

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: S.F.D. reports funding grants from the Arthroscopic Association of North America and Orthopaedic Research and Education Foundation; consulting or advisory fees from Stryker; and speaking and lecture fees from AO North America; is an Editor for Arthroscopy. G.R.J. serves on the editorial or governing board of Journal of Orthopaedic Experience & Innovation and is an editorial board member of Arthroscopy Journal and reports publishing royalties and financial or material support from Elsevier. C.W.N. reports board or committee membership in the Arthroscopic Association of North America, American Academy of Orthopaedic Surgeons, and American Orthopaedic Society for Sports Medicine; educational support and speaker fees from AO Foundation; consulting fees, speaker fees, and research support from Arthrex; and consulting and educational fees from Vericel and Guidepoint. All other authors (B.A.P., C.J.B., T-F.A.C.) declare that they have not known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Supplementary Data

Video 1

This video demonstrates techniques for improving visualization for medial meniscus posterior root repair. These are our disclosures. Standard anterior lateral and anterior medial portals are created, and a diagnostic arthroscopy is performed. A probe is used to confirm that the medial meniscus posterior root is detached and completely torn. As you can see at this point, the posterior medial knee can be very tight, which can make it difficult to introduce instruments to assess and perform an anatomic root repair. In order to improve our visualization, as well as access to the posterior medial knee, there are several techniques that we can utilize. We first began with lengthening and trephination of the medial collateral ligament (MCL), and this is typically done with a pie-crust technique using spinal needle. The spinal needle is first introduced into the joint under direct visualization, then slightly pulled back, and directed proximally aiming at the proximal one-third and femoral insertion of the MCL while applying gentle valgus stress and 20° of knee flexion to allow the joint space to open up as demonstrated in the video. Next, the posterior aspect of the femoral condyle can be gently debrided with a cautery and motorized burr to perform a reverse notchplasty. The posterior cruciate ligament (PCL) synovium can be gently debrided, and we typically debride 1-2 mm of bone to allow for improved visualization and passage of the sutures through and around the meniscus. We then direct our attention to the medial tibial spine. Once again, a cautery and motorized burr can be used to shave down 1-2 mm of the medial tibial spine, which can significantly improve access to allow placement of our drill guide while also creating a bleeding bone bed around the root insertion. After all 3 steps have been performed, you can see we now have great access to the posterior medial aspect of the knee. A cannula is then inserted into the anterior medial portal and a point-to-point transtibial drill guide, and a 2.7 cannulated drill is introduced into the root insertion under direct visualization. Once we have confirmed our root insertion site, a nitinol wire is shuttled through the cannulated drill and retrieved from the anterior medial portal, and a passing suture is then shuttled through the nitinol wire. The surgeon's preferred fixation device is an all-soft tissue, knotless anchor, and this is passed into the prepared tunnel. This device comes with 2 repair stitches. The first stitch is passed through the meniscus in a vertical mattress pattern forming the first part of the modified Mason–Allen configuration using a self-retrieving suture passer. This stitch is shuttled into the anchor through the knotless mechanism. The second stitch is then passed medial to the first stitch completing the rip-stop configuration. Both stitches are then tensioned sequentially until anatomic reduction of the meniscus.