Arthroscopic Medial Meniscus Root Repair With Centralization Using Reversed Suture Anchors for Extruded Medial Meniscus Tears

Abstract

The root of the meniscus, as a core structure maintaining the biomechanical stability of the knee joint, plays a decisive role in delaying the occurrence of osteoarthritis by restricting abnormal displacement of the meniscus and ensuring the integrity of circumferential tension. Although various repair techniques for posterior root tears of the medial meniscus have achieved the goal of anatomical reconstruction, postoperative meniscus extrusion is still common. This pathological displacement is significantly associated with joint space narrowing and osteophyte formation. This technique describes a combined arthroscopic surgical approach, which restores and maintains the function of the meniscus through a centralization technique combined with anchor repair, thereby effectively reducing meniscus extrusion.

The posterior root of the medial meniscus is a core structure that maintains the circumferential tension of the meniscus and the transmission of joint loads. ¹ Its tear (medial meniscus posterior root tear [MMPRT]) is a common type of injury seen in clinical practice. MMPRT disrupts the circumferential fiber continuity of the meniscus, causing the loss of circumferential stress and subsequently leading to pathological meniscal extrusion, that is, the medial meniscus shifts beyond the edge of the medial tibial plateau (extrusion length ≥ 3 mm is defined as medial meniscus subluxation). ² This extrusion phenomenon abnormally increases the contact pressure in the medial compartment, accelerates cartilage degeneration, and significantly increases the risk of progression of knee osteoarthritis. ³ , ⁴

The occurrence of meniscal extrusion is mostly due to MMPRT. ⁵ Its risk factors include aging, increased body mass index, and aggravated varus alignment. ³ Moreover, the extrusion progresses rapidly, and even with good anatomical root repair, it may still persist. ⁶ , ⁷ Currently, although posterior root repair techniques (such as reverse suture anchor reconstruction) can partially restore the anatomical continuity of the meniscus and improve its biomechanical function, the problem of meniscal extrusion remains challenging. ⁸ Meanwhile, methods for correcting meniscal extrusion, such as double‐tunnel suture pull‐out technique, ⁹ knotless suture anchor technique, ¹⁰ and meniscus‐tibial ligament repair, ¹¹ have been widely reported, but the indications for lateral extrusion repair are not uniformly described, and the surgical operation is quite difficult. The ideal surgical method has not yet been agreed upon by the academic community.

Against this background, this article describes a technique which uses double‐reversed anchors to complete the repair and centralization of the posterior root of the meniscus. This technique is expected to focus on the medial meniscus, effectively restore the biomechanics of the posterior root of the meniscus, and provide ideas and solutions for solving the problem of meniscal extrusion.

SURGICAL TECHNIQUE

A comprehensive review of imaging data is essential before the operation. The key steps, points, and precautions are summarized in Table 1, and the advantages and disadvantages of this technique are listed in Table 2. The related video provides a detailed introduction to this technique (Video 1).

TABLE 1.

Pearls and Pitfalls of the Technique

Pearls	Pitfalls
1. Arthroscopic release of the medial collateral ligament through the magic point to expose the medial compartment provides a better surgical field of vision	1. The instruments, such as the Micro SutureLasso, Scorpion, and rasp, should be handled carefully to avoid chondral damage
2. Position the anterior cruciate ligament reconstruction aiming device at the posterior root of the posterior medial area of the meniscus (located at the central edge of the periphery of the tibial articular surface)	2. The postoperative plan must be strictly followed; otherwise, it may lead to failure of the fixation
3. During the operation, strict management of sutures is required. It is recommended to prioritize the completion of the posterior root repair suture threading and confirm the reduction effect before proceeding with the protrusion repair operation to avoid confusion	3. When reversing the anchor into the bone tunnel, it is necessary to repeatedly confirm that the anchor is firmly fixed at the junction area of the thick and thin bone tunnel

TABLE 2.

Advantages and Limitations of the Technique

Advantages	Limitations
1. Centralization helps reduce meniscal extrusion	1. May not be suitable for patients with osteoporosis
2. Reduced the difficulty of placing the anchor and shortened the operation time	2. Penetration of the meniscal body would result in overconstraint of the meniscus
3. Avoidance of additional portals
4. While centralizing, it has a certain repair effect on the meniscus and tibial collateral ligament

VIDEO 1.

Download video file ^{(242.2MB, mp4)}

The patient is positioned supine with the knee flexed at 90°. Arthroscopy surgery is performed using a 30° scope and a standard approach through the medial and lateral portals of the knee joint. Another portal is established 0.5 cm below the medial portal. The medial collateral ligament is released through the magic point to expose the medial compartment. A type II tear according to the Christopher classification happened in the posterior root of the medial meniscus. A radiofrequency is used to debride the remnant meniscus. The posterior root stump is cleared with a shaver and radiofrequency ablation, and the middle part of the meniscus is pushed out with a probe to confirm the extrusion. The tibial targeting device is positioned at the posterior‐medial area of the meniscus posterior root. A 2 cm incision is made on the medial aspect of the tibia, followed by the insertion of a 2.0‐mm Kirschner wire. When the Kirschner wire penetrated the joint cavity, the length of the narrow bone tunnel is measured using an equivalent length wire. Subsequently, a 4.5‐mm bone tunnel is drilled, with a length that is 1.5 cm shorter than the length of the narrow bone tunnel. The spinal needle is inserted through the bone tunnel into the joint cavity. The thread PDS suture is passed through the spinal needle. The spinal needle is removed and the PDS suture is retained. The 3.0‐mm anchor is inserted through the PDS suture in a reverse direction into the bone tunnel and fixed it at the junction of the broad and narrow bone tunnels. The anchor suture is looped around the body of the meniscus with a suture hook and PDS suture and then pulled out through the anteromedial approach without fixation for the time being. The posterior root attachment site is located with the aiming device, and a bone tunnel is established and the second anchor is inserted in the reverse direction in the same way. The anchor suture is passed through the posterior root of the meniscus and pulled out from the anterolateral approach without fixation to leave space for reduction. Finally, pull and tighten the suture of the first anchor, centralize and reset the meniscus, and then use the thread grip tool and the knot pusher to secure the suture; subsequently, complete the posterior root reconstruction of the medial meniscus. The stability of the repaired posterior root of the meniscus is then confirmed. Posterior root of the meniscus is repaired well. Video content can be viewed at https://doi.org/10.1002/atn2.70086.

After successful anesthesia, the patient is placed in a supine position. The left knee anteromedial (AM) and anterolateral approaches are established for arthroscopic exploration. The medial collateral ligament is released through the magic point under arthroscopy (Smith & Nephew) to expose the medial compartment. The posterior root of the medial meniscus is classified as type 2 tear (complete detachment of the posterior root from the attachment site, Figure 1) according to the Christopher classification. Subsequently, the posterior root stump is cleared with a shaver (Smith & Nephew) and radiofrequency ablation (Smith & Nephew), and the middle part of the meniscus is pushed out with a probe (Smith & Nephew) to confirm the extrusion (Figure 2).

FIGURE 1.

The patient is placed in a supine position with the left knee kept in a 20° flexion and valgus position. The posteromedial portal is the observation portal. A type 2 tear happened according to the Christopher classification in the posterior root of the medial meniscus, with the root detached from its attachment point.

FIGURE 2.

Left knee with patient in supine position. The posteromedial portal is the observation portal. Extrusion of the medial meniscus is confirmed by pushing the midbody of the meniscus out of the rim of the MTP using a probe (white arrowhead). (MTP, medial tibial plateau.)

The next step is to establish the bone tunnel and insert the first anchor: A 1 cm incision is made about 2 cm medial to the tibial tubercle. The anterior cruciate ligament reconstruction aiming device (Smith & Nephew) is placed in the posterior‐medial area of the meniscus posterior root (the central edge of the tibial articular surface, Figure 3) through the AM approach. A 2.0 mm thin bone tunnel is first established with a Kirschner wire (Wego), and then, a 4.5 mm drill bit (Smith & Nephew) is used to build a thick bone tunnel (reaching about 15 mm deep to the surface of the tibial plateau). A PDS suture (Ethicon; Johnson & Johnson) is introduced through the bone tunnel opening with an epidural needle (Qiong Hua) and pulled out from the anterolateral approach. The tail of the first 3.0 anchor (Johnson & Johnson) is tightened and then inserted in the reverse direction, fixed at the junction of the thick and thin bone tunnel (Figure 4). ⁸ The anchor suture is looped around the body of the meniscus with a suture hook (Johnson & Johnson) and PDS suture and then pulled out through the AM approach without fixation for the time being (Figure 5).

FIGURE 3.

Left knee with patient in supine position. Place the tibial tunnel targeting guide at the posterior‐lateral inner region of the meniscus (in the central area of the peripheral edge of the tibial joint surface).

FIGURE 4.

Left knee with patient in supine position. (A) The medial portal is the observation portal. With the assistance of the epidural needle, the PDS suture is introduced into the joint cavity through the bone opening. (B) The anchor suture is tied tightly with PDS suture and then introduced into the joint cavity. (C) After the suture is tightened, the anchor is fixed at the junction area of the thick and thin bone tunnel. (PDS, Polydioxanone.)

FIGURE 5.

The patient is placed in a supine position with the left knee kept in a 20° flexion and valgus position. The posteromedial portal is the observation portal. The anchor sutures are passed through the meniscal body using a suture passer and retrieved via the AM portal (A), with final fixation deferred until completion of meniscal centralization (B). (AM, anteromedial; PDS, Polydioxanone.)

After the first anchor operation is completed, the posterior root footprint area is freshened with radiofrequency ablation and a curette (Smith & Nephew) through the AM approach. The posterior root attachment site is located with the aiming device, and a bone tunnel is established and the second anchor is inserted in the reverse direction in the same way. The anchor suture is passed through the posterior root of the meniscus and pulled out from the anterolateral approach without fixation to leave space for reduction (Figure 6). Finally, pull and tighten the suture of the first anchor, centralize and reset the meniscus, and then tie it to fix (Figure 7); subsequently, complete the posterior root reconstruction of the medial meniscus (Figure 8).

FIGURE 6.

The patient is placed in a supine position with the left knee kept in a 20° flexion and valgus position. The posteromedial portal is the observation portal. The anchor suture is passed through the meniscal posterior root using a suture passer and retrieved via the AL portal, with final fixation intentionally deferred to preserve mobility for subsequent meniscal reduction maneuvers. (AL, anterolateral.)

FIGURE 7.

The patient is placed in a supine position with the left knee kept in a 20° flexion and valgus position. The posteromedial portal is the observation portal. After applying controlled traction to the first anchor suture, the meniscus is centralized and anatomically repositioned before completing fixation with surgical knots.

FIGURE 8.

The patient is placed in a supine position with the left knee kept in a 20° flexion and valgus position. The posteromedial portal is the observation portal. After the centralization process is completed, the posterior root reconstruction of the meniscus is carried out.

Postoperative Rehabilitation

After the surgery, a brace is used to immobilize the knee joint for 4 weeks. Gradual weight‐bearing is initiated at 4 weeks postoperatively, and full weight‐bearing is allowed at 8 weeks. From the 4th week, range‐of‐motion exercises are started, initially limited to within 90°. By 6 weeks, the range of motion exceeds 90°, and progressive exercises are implemented to achieve a full range of motion.

DISCUSSION

MMPRT causing meniscal extrusion is a key focus and challenge in clinical treatment. ¹² The fundamental reason is the loss of the meniscus’ normal load transmission function. Correcting extrusion is crucial for restoring the meniscus’ mechanical function and delaying the progression of osteoarthritis. However, simple repair of the torn root often fails to effectively reduce extrusion. ¹³ , ¹⁴ , ¹⁵ Therefore, the combined application of root repair and meniscal centralization techniques has become a key strategy. Studies have shown that the combined technique can significantly improve patient functional scores (such as Lysholm and KOOS scores), reduce extrusion distance, and restore the meniscus’ circumferential stress distribution. ¹⁶ , ¹⁷ Biomechanical studies also indicate that centralization techniques can optimize meniscal mechanical performance and reduce the risk of osteoarthritis. ¹⁸ , ¹⁹

Several enhanced repair techniques for meniscal extrusion have been explored, including double‐tunnel suture pull‐out, knotless suture anchor fixation, and meniscus‐tibial ligament repair. However, each has its limitations. The double‐tunnel suture pull‐out technique is widely used in clinical practice with clear long‐term efficacy, but the excessive length of the suture in the bone tunnel may lead to “bungee effect” and “suspension effect,” affecting the healing outcome. The knotless suture anchor technique is convenient to operate and reduces soft tissue irritation, but it has the risk of insufficient anchor fixation strength and long‐term suture cutting. ¹⁰ Meniscus‐tibial ligament repair has a wide range of applications, but open surgery may damage the medial collateral ligament, and small incision surgery may also limit ligament movement. ²⁰ In comparison, the technique described in this technical note has several advantages: first, it significantly enhances the pull‐out strength by placing the anchor in the subchondral bone in reverse; second, it avoids the risks of “bungee effect” and “suspension effect” while maintaining mechanical stability; third, it simplifies the anchor placement process, eliminating the need for additional approaches and reducing the operation difficulty; finally, since the meniscotibial ligament is prone to rupture at the target location (the centralization of the meniscus), this technique also has a certain ligament repair effect, further enhancing its comprehensive clinical value.

During the surgical procedure, a precise preoperative magnetic resonance imaging assessment of the tear type and extrusion degree is necessary. Intraoperatively, the medial collateral ligament is released at the magic point through arthroscopy to fully expose the medial compartment. After cleaning the residual ends, radiofrequency release is performed to ensure the meniscus’ repositioning tension. For the centralization operation, the bone tunnel is precisely located at the edge of the tibial articular surface through the AM approach, and the anchor is placed in reverse with the assistance of PDS suture and fixed. During the operation, strict management of the suture is required. It is recommended to complete the posterior root repair suture threading and confirm the repositioning effect first and then proceed with the extrusion repair operation to avoid confusion.

Although this technique provides an approach for the treatment of extrusion, it still has limitations: first, there is a risk of excessive constraint, and the long‐term mechanical adaptability of the medial meniscus needs further verification; second, most of the existing clinical evidence is based on short‐term follow‐up, and there is a lack of large‐scale long‐term research support; finally, even with the combination of anatomical repair and centralization techniques, extrusion may still persist, and the differential efficacy in patients of different ages, body mass indices, and lower limb alignment also requires further exploration.

DISCLOSURES

The authors (C.M., J.W., M.L., C.Q., T.Z., Q.C., C.H.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

FUNDING

This work was supported by Inner Mongolia Autonomous Region Public Hospital High Level Clinical Specialty Development Technology Project Foundation (2023SGGZ140), Natural Science Foundation of Inner Mongolia (2022MS08015), Inner Mongolia Autonomous Region Science and Technology Program Foundation (2022YFSH0028), and Inner Mongolia Autonomous Region Health Science and Technology Program Foundation (202201344).

Meng Chenyang, Wang Junyi, Liu Ming, Qiao Chenggang, Zhang Tiexin, Cheng Qi, Han Changxu. Arthrosc Tech. 2026; 15:e70086. 10.1002/atn2.70086