AOSM Meniscal root repairs using the trapezoidal stitch technique

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The meniscus plays a key role in shock absorption, in load distribution, in proprioception, in the guidance of the tibiofemoral contact, and in secondary stabilization of the knee joint. Medial meniscus posterior root tears (MMPRTs) result in the separation of the meniscus into two pieces, where only one end remains attached to the tibia. This causes a peripheral displacement of the meniscus, a loss in hoop stress, and a compromise in functional load distribution. Recently, clinical studies have reported that arthroscopic pull-out repairs for MMPRTs show favorable clinical and radiographic results. We propose that the trapezoidal stitch technique, compared to conventional methods, provides not only a stronger fixation for damaged medial meniscus roots but also a larger contact area and superior binding at the MMPRT.

Keywords: Knee, Arthroscopy, Meniscus

Meniscal root repairs using the trapezoidal stitch technique

Jun Seok Kim, Seok Jun Kim, Jae Yeon Kong, Jong Seok Oh*

Department of Orthopedic Surgery, West Busan Centum Hospital, Busan, Korea

CC This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/

by-nc/4.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received October 19, 2016; Revised December 27, 2016; Accepted December 27, 2016

Correspondence to: Seok Jun Kim, Department of Orthopedic Surgery, West Busan Centum Hospital, 226 Saebyeok-ro, Sasang-gu, Busan 46973, Korea. Tel: +82-51-329-3000, Fax: +82-51-329-3197, E-mail: [email protected]

*Current affiliation: Himnaera Hospital, Busan, Korea Arthroscopy and

Orthopedic Sports Medicine

AOSM

INTRODUCTION

The meniscus plays a key role in shock absorption, in load distribution, in proprioception, in the guidance of the tibiofemoral contact, and in secondary stabilization of the knee joint. Meniscal injury has been shown to result in a decrease in tibio-femoral contact area and a concomitant increase in articular cartilage peak pressure [1]. Medial meniscus posterior root tears (MMPRTs) result in the separation of the meniscus into 2 piecess, where only one end is attached to the tibia. This renders the meniscus to be displaced peripherally and to lose hoop stress and functional load distribution [2], predis- posing individuals to osteoarthritis due to altered joint contact stress [3]. Partial meniscectomy has been the conventional treatment for this condition [1,4], but biomechanical studies have shown that the consequences of MMPRTs are similar to those of total meniscectomy and that reparation restores peak contact pressure to normal [5,6]. Recently, clinical studies on arthroscopic pull-out repairs of MMPRTs have reported favorable clinical and radiographic results [7].

A number of simple stitching-based techniques to repair the medial meniscus root have been proposed [6–9].

However, only small area of bone to meniscus contact could be obtained using the conventional one transosseous tunnel technique. Therefore, we propose the use of a trapezoidal stitch as a treatment option for torn medial meniscus roots. We anticipate that this will provide a more secure and stronger fixation, as well as a large contact area and superior binding of the torn end of the posterior medial meniscus, and may potentially enhance the healing of repaired menisci.

TECHNIQUE

A routine arthroscopic examination of the knee joint was performed using standard anterolateral and anteromedial portals with the knee joint distended through an arthroscopic infusion pump. In general, we preferred to perform a small notchplasty on the ipsilateral femoral condyle to improve access to and to visualize the torn meniscal root and the root insertion footprint, as well as to improve access for instrumentation. For knees with

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intact cruciate ligaments, care was taken to minimize disruption to the ligament origin when performing the notchplasty. And we used the medial collateral ligament

‘piecrusting’ release [9]. These steps allowed for a sub- stantially improved visualization of the root tear, the na- tive insertion site, the repair bed preparation, the tunnel position, and, ultimately, the root fixation. After confirm- ing the lesion, the footprint was confirmed by removing the cartilage of the tibial plateau, which was attached to the posterior root of the medial meniscus, with a curette and a round burr inserted through the anteromedial portal. The round burr was extended to the insertion site of the posterior horn of the meniscus, slightly medial or anteromedial to the posterior cruciate ligament insertion site. A 10-mm diameter region of cortical bone was removed to reattach the meniscus.

Under visualization from the anterolateral portal, the anterior cruciate ligament tibial drilling guide (Linvatec, Largo, FL, USA) was inserted through the anteromedial portal. A 40° to 45° sleeve guide was fixed to the the anterolateral cortex of the proximal tibia after a 2-cm vertical incision was made and the extensor muscle of the tibia was elevated. A tibial tunnel was made from the anterolateral cortex of the proximal tibia to the anterolateral side of the footprint of the MMPR by using a guide pin with a 2.9-mm cannulated drill bit.

A crescent-shaped suture hook (Linvatec), loaded with No. 1 polydioxanone (PDS), was passed through the anteromedial portal. We used the tip of the suture hook to penetrate the detached portion of the medial meniscus posterior horn 3-mm medially and slightly posteriorly to the torn edge and vertically from the femoral side to the tibial side. Then, a No. 1 PDS was advanced through the suture hook, and the tibial side of the No. 1 PDS was taken out through the anteromedial portal, using a suture retriever. A shuttle relay method was used to replace the first suture with a fiberwire (Arthrex, Naples, FL, USA) for more tensile strength. The other PDS strand was placed anteriorly to the first suture in the same manner. As the next step, the superior ends of the two simple sutures (one fiberwire, one PDS) were tied outside of the portal, and the inferior end of the second suture was then pulled. Using the shuttle relay method, the second suture was exchanged with the first fiberwire suture. Finally, the horizontal loop was completed (the method so far is similar to the technique described by Ahn et al. [10]). An- other PDS strand was placed posteromedially to the first suture, near the meniscocapsular junction in the same

manner. The inferior end of the PDS simple suture and the posterior suture of horizontal loop were tied outside of the portal, and the superior end of the third suture was then pulled. Again, using the shuttle relay method, the third suture was exchanged with a fiberwire suture. Like- wise, another PDS strand was placed anterior to the third suture through the same portal. And the inferior end of the PDS simple suture and the anterior suture of horizontal loop were tied outside of the portal, and the superior end of the forth suture was then pulled. Using the

A

B

C

Fig. 1. Surgical technique of trapezoidal stitch. (A) The detached portion of the medial meniscus posterior horn (arrow) was penetrated by the sharp tip of the suture hook. Then, No. 1 polydioxanone (PDS) (Linvatec) was advanced through the suture hook, and the tibial side of the No.

1 PDS was taken out through the anteromedial portal using a suture retriever. Using the shuttle relay method, the first suture was exchanged with a fiberwire (Arthrex) for more tensile strength. (B) Using the shuttle relay method, the third suture was exchanged with the fiberwire suture.

(C) Both ends of the fiberwire suture were passed through the wire loop that had been pre-exposed to the anteromedial portal and pulled out through the anterolateral cortex of the proximal tibia (arrowhead, bone tunnel).

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shuttle relay method, the fourth suture was exchanged with a fiberwire suture. A wire loop was advanced into the intraarticular space through the tibial tunnel and was retrieved through the anteromedial portal. Both ends of the fiberwire suture were passed through the wire loop that had been preexposed at the anteromedial portal and pulled out through the anterolateral cortex of the proximal tibia. Once we confirmed that there was sufficient reduction and tension of the medial meniscus, the fiberwire sutures were fixed onto the anterior cortex of the proximal tibia by tying them using EndoButtons (Smith

& Nephew, Mansfield, MA, USA), whilst maintaining the knee in 90° of flexion (Fig. 1, 2). Then, arthroscopically, we exerted tension over the suture strand, covering the whole denudated foot print; we did not observe unstable movement or any abnormal furling during probing. No differences were observed between the tied menisci in full flexion and those in full extension of the knee.

Postoperative management

A cylinder leg splint was applied in full extension for 2 postoperative weeks, and a limited-motion brace was subsequently applied to control motion. Postoperative

rehabilitation consisted of partial weight-bearing for the first 6 weeks. Then, progressive weight-bearing was begun with the goal to achieve full weight-bearing by the 8th postoperative week. Patients were instructed to perform quadriceps muscle exercises as well as the straight-leg raise several times daily. In the immediate postoperative period, a continuous passive motion machine was used the first month; the range of motion was set at 0° to 90°, which was gradually increased to flexion degrees of up to 135°. Full flexion and squatting were allowed 3 months postoperatively. Patients returned to exercise after 6 postoperative months.

DISCUSSION

The meniscus protects the articular cartilage from high- contact pressure on account of their longitudinally orientated intrameniscal fibers, which generates circumferential tension in the meniscus when vertical load is applied (i.e., hoop stress). Radial tears of the meniscus result from trauma or from degenerative changes, and they can occur anywhere in the meniscus. Radial tears of the medial meniscus have been reported to be com-

Fig. 2. Root tear repaired using the trapezoidal technique. (A) Intraoperative photography of a root tear of the posterior horn of the medial meniscus. (B) After repaired root tear. (C) Healed root tear at 6 months after repair. (D) Suffi- cient resistance was felt by probing.

A B

C D

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mon in elderly patients, who generally suffer from severe knee pain [6]. Through in vitro biomechanical studies, Allaire et al. [5] have shown that radial tears of the medial meniscus posterior root (MMPR) are biomechanically equivalent to total meniscectomy, both of which leads to accelerated degenerative changes. The loss in attachment of root ends means that the normal centrifugal pull of the meniscocapsular attachments is now able to displace the meniscus peripherally. The resultant loss in capacity to distribute force and the peripheral subluxation of the meniscus, occurring at the radial tear of the MMPR, compromise the ability of the meniscus to protect the articular surface of the knee.

In the past, partial meniscectomy was used to treat MMPRT by some authors even though it cannot fully restore biomechanical function of the meniscus [11].

A surgical repair is a reasonable option in acute, sub- acute, or chronic tears in which there are little to no articular cartilage injury and good preservation of the meniscal tissue. Several repair techniques have been reported in the literature. For instance, Raustol et al. [12]

used a long pin and sutures, which were passed through a posteromedial accessory portal in a transosseous fash- ion. Recently, Griffith et al. [13] described a technique of using decorticated footprints via suture tunnels over a bone bridge. Ahn et al. [8] reported pull out suture using a posterior trans-septal portal. Important prerequisites for a complete and successful healing of the meniscal root tears are good initial holding strength and a large tissue-bone contact area. Because the main fibers of the meniscus are circumferential fibers that are tangentially oriented to the root insertion, simple stitching produces a weak holding strength and can lead to a less ideal recu- perating experience for patients, due to treatment failure.

The potential risk of premature suture pullout may be

reduced with the trapezoidal stitch.

This repair was done using a pull out suture through a single transosseous tunnel. However, single transosseous tunnels have disadvantages of low contact area and contact pressure between the posterior horn and the decorticated bone. So some authors have advocated the use of two tibial tunnels to increase and to evenly distribute contact pressure between the meniscus root and the insertion site [9]. With such a double transosseous pullout suture technique, tunnel coalition or breakage can be problematic, resulting in a limited small root insertion area. The technique we proposed in this report, notwith- standing the disadvantages of single-point fixation, may provide a relatively wide and balanced contact area between the root and the insertion area; thereby, improving the enthuses-bone healing potential.

We used an all-arthroscopic trapezoidal suture technique in an attempt to restore the attachment. In this study, the indications for this technique were Outerbridge 1–2 arthritic changes and minimal varus malalignment.

This trapezoidal suture technique has been shown to provide a more secure and stronger fixation, greater holding strength, and larger contact area (Fig. 3). However, further biomechanical studies are required to demonstrate that this technique, compared to conventional simple stitch methods, can indeed provide such benefits even when applied to meniscal tissue. Lastly, the technical difficul- ties such as the suturing of the posteromedial stitch near the meniscocapsular junction have been associated with this technique.

CONFLICT OF INTEREST

No potential conflict of interest relevant to this article was reported.

Fig. 3. Benefits of this technique. (A) Conventional suture technique. (B) Trapezoidal suture technique. Trapezoi- dal suture technique may provide large contact area than conventional simple stitch and may potentially enhance healing of repair.

A B

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