Abstract
The meniscal roots are critical in maintaining the normal shock absorbing function of the meniscus. If a meniscal root tear is left untreated, meniscal extrusion can occur rendering the meniscus nonfunctional resulting in degenerative arthritis. Two main repair techniques are described: (1) suture anchors (direct fixation) and (2) sutures pulled through a tibial tunnel (indirect fixation). Meniscal root repair using a suture anchor technique is technically challenging requiring a posterior portal and a curved suture passing device that can be difficult to manipulate within the knee. We present a technique for posterior medial meniscus root repair using 3 sutures (1 leader, 2 cinch), standard arthroscopy portals, and transtibial fixation. Overall, this technique simplifies a challenging procedure and allows for familiarity and efficiency.
The meniscal roots are critical in maintaining the normal shock absorbing function of the meniscus.1 Harner et al.2 showed that peak contact pressures after a medial meniscus root tear were similar to that after total medial meniscectomy. Contact pressure returned to normal after meniscal root repair. If left untreated, meniscal extrusion can occur rendering the meniscus nonfunctional resulting in degenerative arthritis of the knee.3, 4 Chung et al.5 compared the outcomes of 37 patients with meniscal root repairs with 20 patients who underwent partial meniscectomies. The repair group had superior subjective knee rating and knee function scores with less radiographic progression of arthritis.
Two main repair techniques have been described: suture anchors (direct fixation) and sutures pulled through a tibial tunnel (indirect fixation). Meniscal root repair using a suture anchor technique is technically challenging. This requires a posterior portal and a curved suture passing device that can be difficult to manipulate within the knee.6, 7 We present a technique for posterior medial meniscus root repair using 3 sutures (1 leader, 2 cinch), standard arthroscopy portals, and transtibial fixation.
Surgical Technique
Patient Positioning and Visualization
In addition to standard arthroscopy instrumentation, additional specialized equipment is required to perform this technique (Table 1). The patient is positioned supine and the operative extremity is prepped and draped in the usual fashion for knee arthroscopy. A standard anterolateral viewing portal is established followed by an anteromedial portal under direct visualization (Video 1). The anteromedial portal is positioned just proximal to the medial meniscus to allow instrument passage to the posterior horn. A diagnostic arthroscopy is performed paying special attention to the meniscal root attachments (Fig 1).
Table 1.
Equipment Required to Perform a Posterior Medial Meniscus Root Repair Using the Described Technique
| Special equipment required for posterior horn root repair |
| Arthroscopic cannula |
| Self-retrieving suture passing device |
| Free No. O nonabsorbable sutures |
| No. 0 FiberLink sutures (×2) |
| No. 2 FiberSick |
| Variable angle transtibial meniscal root drill guide |
| 6-mm FlipCutter retrograde reamer |
| 5.5-mm SwiveLock anchor |
Fig 1.
Arthroscopic images of a left knee. (A) Medial meniscus posterior root tear. (B) Arthroscopic probe showing instability of the medial meniscus root tear.
When approaching the posterior meniscus for root repair, adequate visualization and easy instrument passage are critical. Visualization can be improved by removing a small amount of bone from the posterior aspect of the notch (reverse notchplasty) and/or debriding the synovium overlying the posterior cruciate ligament. If it is difficult to pass instruments to the posterior root while placing a valgus force on the knee, the medial collateral ligament can be fenestrated using a spinal needle.
Creation of the Tibial Bone Socket
After adequate visualization has been obtained, we prefer to create the tibial socket first. This allows easy passage of the drill guide before suture placement within the knee. A 2-cm incision is made just proximal and medial to the tibial tuberosity. This tibial guide is precontoured to the femoral condyle and has a variable angle handle allowing for accurate tunnel placement with minimal torque (Arthrex, Naples, FL) (Fig 2A). Retrodrilling of the tibia is performed with a 6.0-mm FlipCutter (Arthrex). The FlipCutter is a 3.5-mm-diameter pin that converts to a 6.0-mm-diameter reamer (Fig 2 B and C). This has the advantage of creating a socket, which assists in preserving tibial bone stock, especially when performing concomitant procedures such as anterior cruciate ligament reconstruction.
Fig 2.
Left knee tibial tunnel preparation for medial meniscus posterior root repair. (A) Variable angle transtibial meniscal root guide being positioned through the anteromedial portal while viewing with the arthroscope through the anterolateral portal. (B) Arthroscopic image of the transtibial guide overlying the medial meniscus posterior root attachment site. (C) A 3.5-mm FlipCutter pin advancing intra-articularly at the anatomic insertion of the posterior root of the medial meniscus. (D) FlipCutter after deploying the 6-mm reamer before retroreaming the tibia 10 mm.
The tibial drill guide is inserted through the anteromedial portal and visualized through the anterolateral portal. The guide tip is placed at the center of the meniscal root footprint (Fig 2A). A 2.4-mm wire is advanced intra-articularly through the inner cannula to the tip of the guide. The drill guide is then carefully removed. The outer cannula is impacted into the anterior cortex of the tibia. The 3.5-mm-diameter FlipCutter pin drilled through the cannula in the same trajectory as the 2.4-mm wire (Fig 2B). The FlipCutter is converted to a 6.0-mm reamer under direct arthroscopic visualization. The tibia is retrodrilled 10 mm (Fig 2C). The FlipCutter is advanced back into the joint, converted back to a 3.5-mm-diameter pin, and removed from the tibia. A No. 2 FiberStick suture (Arthrex) is advanced through the tibial tunnel (Fig 3A) and the FiberWire passing suture is retrieved through the anteromedial portal (Fig 3B). This is then docked in the anterolateral portal to prevent entanglement with the meniscal sutures during their placement (Fig 3C).
Fig 3.
Placement and docking of a transtibial shuttling suture during posterior medial meniscal root repair. (A) Arthroscopic image of a No. 2 FiberStick advanced through the tibial tunnel into an intra-articular position. (B) A grasping device is used to retrieve the No. 2 FiberWire through the anteromedial portal while viewing anterolaterally. (C) Viewing with the arthroscope anterolaterally after the shuttling suture has been retrieved anterolaterally and a PassPort cannula has been inserted anteromedially.
Passage of Meniscal Root Sutures (1 Leader, 2 Cinch)
A PassPort cannula (Arthrex) is introduced through the anteromedial portal to aid in suture management and prevent a soft-tissue bridge (Table 2). The loop end of an O-FiberLink (Arthrex) is passed through the meniscal root using a self-retrieving suture passing device (Knee Scorpion; Arthrex) (Fig 4A). After removal from the wound the free end of the suture is passed through the loop and traction is then applied (Fig 4B). A cinch knot configuration is then created over the meniscus (Fig 4C).8 This is repeated 10 mm medial to the initial suture to provide 3 sutures (1 leader, 2 cinch) spanning the posterior root of the meniscus. A knot pusher or probe can be used to assist in tightening the cinch knot as deemed necessary. Finally, a simple stitch is placed at the free edge of the root, just lateral to the first cinch knot, using an O-FiberWire (Arthrex) suture. This is known as a “leader stitch” and is used to assist in reducing the apex of the meniscal root into the tibial socket. The use of 3 different colored sutures allows for easy identification during tensioning and fixation.
Table 2.
Pearls and Pitfalls
| Pearls |
| Variable angle transtibial meniscal root drill guide allows easy placement over the anatomic attachment site of the meniscal root |
| Transtibial drilling before meniscal suturing avoids suture entanglement |
| PassPort cannula prevents soft-tissue bridge formation |
| Self-retrieving suture passing device allows fixation through standard arthroscopy portals |
| Pitfalls |
| Fixation failure can occur if a patient is not able to follow the established rehabilitation protocol |
| Transtibial meniscal root repair in a patient with open physis can lead to growth arrest |
Fig 4.
Technique for cinch suture placement. (A) Arthroscopic image of a 0-FiberLink suture being passed through the posterior root of the medial meniscus with a self-retrieving suture passing device. (B) Image after the free end of the 0-FiberLink suture has been passed through the loop end creating a cinch configuration. (C) Arthroscopic image after tension has been applied to the free end of the 0-FiberLink and the cinch has tightened around the posterior root of the medial meniscus.
Suture Passage Into Tibial Socket
The No. 2 FiberStick suture resting in the lateral portal is now retrieved through the PassPort cannula (Arthrex). All 6 free ends of the meniscal sutures are passed through the FiberStick suture loop and shuttled out the tibial tunnel. The leading suture is identified (most lateral knot position directly through the meniscal root). Moderate tension is applied to the leader stitch, reducing the meniscal root into the tibial socket. The remaining 2 cinch sutures are then tensioned to increase the footprint and provide additional stability to the repair. Occasionally the meniscal root will not be adequately reduced by the leading suture. In this circumstance, the assistance of a probe and variable tension to the 2 cinch sutures is often helpful.
Tibial Fixation of Meniscal Root Sutures
Tibial fixation is obtained with a 4.75-mm BioComposite SwiveLock anchor (Arthrex). A 2.4-mm guide pin is drilled 1 cm distal to the FlipCutter hole in the anteromedial tibial (Fig 5A). This pin is over-reamed with a 4.5-mm reamer to a depth of 20 mm (Fig 5B). The tibial cortex is tapped using a 4.5-mm tap. The knee is cycled from 0° to 90° ten times to remove creep from the system. The 6 free ends of the meniscal sutures are passed through the eyelet of the SwiveLock and tension is applied as described above. The meniscal root is confirmed to be well reduced with the knee in 30° of flexion, and the SwiveLock anchor is advanced into the reamed/taped tibial hole (Fig 5C).
Fig 5.
Placement of a SwiveLock anchor. (A) A 2.4-mm guide pin being drilled 1 cm distal to the tibial tunnel. (B) The guide pin being over-reamed with a 4.5-mm cannulated reamer to a depth of 20 mm. (C) A 4.75-mm SwiveLock being advanced while holding tension on the suture.
Final Result
The arthroscope and probe are reinserted into the knee to confirm that anatomic stable fixation has been obtained (Fig 6).
Fig 6.
Arthroscopic image of the medial meniscus posterior root after transtibial repair.
Rehabilitation
Weight bearing in full extension is limited to toe touch and knee flexion is limited to 90° until 4 weeks after surgery. After 4 weeks, use of the brace is discontinued and the patient may begin full weight bearing and full knee range of motion. Knee loading at flexion angles greater than 90° is not allowed until 4 months postoperatively, at which point patients are typically allowed to return to activity as tolerated.
Discussion
Meniscal root tears have been shown to render the meniscus nonfunctional. However, when a posterior meniscal root repair is performed, the peak contact pressures are returned to their normal state.9 This has been validated clinically where healed meniscal root repairs have been shown to decrease the rate of arthritic progression.10 Kim et al.10 compared transtibial fixation with suture anchor fixation for posterior root medial meniscus tears. A total of 45 patients (22 suture anchor—group 1; 23 transtibial—group 2) were assessed at 2 years postoperatively. Both groups showed significant functional improvements and significant reductions in meniscal extrusion. Incomplete healing was identified in 11 patients in group 1 and 12 patients in group 2. Regardless of the technique, patients with incomplete healing showed progression of cartilage degeneration.
If transosseous repair is desired, then suture configuration must be determined. Anz et al.11 biomechanically compared 2 simple sutures, 1 inverted mattress, 1 double-locking loop, and 2 double-locking loops. They showed that the double-locking loop provided the greatest load to failure when compared with the other suture configurations. However, they also showed increased surgical time. There are currently no biomechanical or clinical studies evaluating the cinch stitch configuration used in the technique described in this Technical Note. However, it is theorized that the cinch configuration improves pullout strength while only requiring a single pass of the suture maintaining simplicity and efficiency.
The described technique for medial meniscus posterior root repair has advantages over previously described techniques (Table 3). First, the procedure can be completed through standard arthroscopy portals and a posterior portal is not required. Second, the new variable angle transtibial guide allows drilling to be performed accurately with minimal torque on the handle. Third, the cinch sutures allow robust capture of the meniscal root with a single passage of the suture minimizing surgical time. Overall, these advantages simplify a challenging procedure and allow for familiarity and efficiency.
Table 3.
Advantages and Limitations
| Advantages |
| Anatomic meniscal root reduction |
| The large surface area of meniscus reduced into bone socket improves healing potential |
| Stable cortical fixation |
| Standard arthroscopic portals |
| Limitations |
| Bone tunnel required |
| Risk for tunnel convergence with concomitant cruciate ligament reconstruction |
| Theoretical risk for neurovascular injury with errant transtibial wire placement |
Footnotes
The authors report the following potential conflicts of interest or sources of funding: M.J.S. receives support from Arthrex and Stryker. A.J.K. receives support from Arthrex, Arthritis Foundation, Ceterix, and Histogenics.
Supplementary Data
Diagnostic arthroscopy. Standard anterolateral and anteromedial portals are established. In this cadaveric specimen, the posterior root of the medial meniscus has been transected. Transtibial drilling: a transtibial, variable angle contoured meniscal root drill guide is positioned over the anatomic attachment site of the posterior meniscal root. A 2.4-mm drill is advanced into an intra-articular position at the tip of the guide. The transtibial guide is removed from the joint leaving the wire in situ. The outer cannula is impacted into the anterior tibial cortex. The 2.4-mm drill is then removed and a 3.5-mm FlipCutter drill is advanced into the knee using the same drilling trajectory. The 6-mm reamer is deployed and a socket is retroreamed to a depth of 10 mm. A No. 2 FiberStick is advanced through the tibial socket and the No. 2 FiberWire shuttling suture is retrieved anteromedially. This is then docked in the anterolateral portal to prevent entanglement with the meniscal sutures. A PassPort cannula is placed in the anteromedial portal to prevent soft-tissue bridge formation during meniscal suturing. Meniscal sutures: sutures are passed through the meniscus using a self-retrieving suture passing device. Two cinch knot configurations are created with 10 mm of separation at the meniscal root. A third simple stitch (leader stitch) is placed at the most lateral apex of the meniscal root. Transtibial shuttling: the shuttling suture that was previously docked in the lateral portal is retrieved through the PassPort cannula. The 6 free ends of the meniscal sutures are pulled through the tibial tunnel. Moderate tension is then applied first to the leader stitch and then the cinch knots. Adequate reduction of the meniscal root must be confirmed before fixation. Tibial fixation: tibial fixation is obtained using a 4.75-mm BioComposite SwiveLock anchor (Arthrex, Naples, FL). A 2.4-mm guide pin is drilled 1 cm distal to the tibial tunnel. This is over-reamed with a 4.5-mm reamer to a depth of 20 mm. The 6 free ends of the meniscal sutures are passed through the eyelet of the SwiveLock anchor. The knee is then held in 30° of flexion, tension is maintained on the meniscal sutures, and the anchor is screwed into place. Final result: after completion of the fixation the arthroscope and probe are reinserted into the knee. The meniscal root is well reduced into the tibial socket and there is minimal motion when attempts are made with the probe. Stable fixation was achieved.
References
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Diagnostic arthroscopy. Standard anterolateral and anteromedial portals are established. In this cadaveric specimen, the posterior root of the medial meniscus has been transected. Transtibial drilling: a transtibial, variable angle contoured meniscal root drill guide is positioned over the anatomic attachment site of the posterior meniscal root. A 2.4-mm drill is advanced into an intra-articular position at the tip of the guide. The transtibial guide is removed from the joint leaving the wire in situ. The outer cannula is impacted into the anterior tibial cortex. The 2.4-mm drill is then removed and a 3.5-mm FlipCutter drill is advanced into the knee using the same drilling trajectory. The 6-mm reamer is deployed and a socket is retroreamed to a depth of 10 mm. A No. 2 FiberStick is advanced through the tibial socket and the No. 2 FiberWire shuttling suture is retrieved anteromedially. This is then docked in the anterolateral portal to prevent entanglement with the meniscal sutures. A PassPort cannula is placed in the anteromedial portal to prevent soft-tissue bridge formation during meniscal suturing. Meniscal sutures: sutures are passed through the meniscus using a self-retrieving suture passing device. Two cinch knot configurations are created with 10 mm of separation at the meniscal root. A third simple stitch (leader stitch) is placed at the most lateral apex of the meniscal root. Transtibial shuttling: the shuttling suture that was previously docked in the lateral portal is retrieved through the PassPort cannula. The 6 free ends of the meniscal sutures are pulled through the tibial tunnel. Moderate tension is then applied first to the leader stitch and then the cinch knots. Adequate reduction of the meniscal root must be confirmed before fixation. Tibial fixation: tibial fixation is obtained using a 4.75-mm BioComposite SwiveLock anchor (Arthrex, Naples, FL). A 2.4-mm guide pin is drilled 1 cm distal to the tibial tunnel. This is over-reamed with a 4.5-mm reamer to a depth of 20 mm. The 6 free ends of the meniscal sutures are passed through the eyelet of the SwiveLock anchor. The knee is then held in 30° of flexion, tension is maintained on the meniscal sutures, and the anchor is screwed into place. Final result: after completion of the fixation the arthroscope and probe are reinserted into the knee. The meniscal root is well reduced into the tibial socket and there is minimal motion when attempts are made with the probe. Stable fixation was achieved.