*6.2.2.2 Suture anchor technique*

This technique was less popular when compared with transtibial technique due to the difficulty in placement of the anchor suture. This technical step involved the preparing the meniscal tissue and bed of the bone, placement of suture anchor, stitched the torn meniscal tissue, and tightened the knot (**Figure 11**).

The disadvantages of this technique were; 1. Difficult of suture anchor placement, 2. Potential cartilage irritation due to knots, 3. Fixation might loosen if anchor is not well placed, 4. Additional costs of suture anchor. To ease the placement of anchor suture, we proposed a technique to repair medial meniscus posterior root by using a curved sleeve soft anchor suture, made a far medial vertical portal, and flexed the knee while drilling the tibia for anchor suture placement (**Figure 12**) [60].

There were several methods to place anchor sutures proposed by several authors. Placing the anchor from the posteromedial portal was one option [61]. Also there was a technique which retrograde insertion of a soft anchor suture to the transtibial tunnel. So, additional portal for anchor placement was not required [62]. Functional outcome after repair showed a significant improvement. Complete healing rate form MRI was not different from transtibial repair. The meniscus extrusion was also not significantly reduced from pre-operative, similar to transtibial repair [27, 63].

Many comparison studies were made between transtibial technique and suture anchor technique because of their own advantages and disadvantages (**Table 1**).

In a biomechanics study by Feucht et al., Suture anchor provided lower displacement after cyclic loading and higher stiffness compared with the transtibial technique. However, both techniques did not reach the strength of the native tissue [57].

**Figure 11.** *Schematic drawing showed suture anchor repair of the medial meniscus root.*

#### **Figure 12.**

*Pictures of anchor suture repair for medial meniscus root tear. A: Placement of curved drill sleeve for soft anchor suture, B: After repair with 2 simple stitches.*


#### **Table 1.**

*Advantages and disadvantages of transtibial technique compared with suture anchor technique.*

In contrast, a study by Wu et al. showed that anchor suture had lower maximum load and stiffness compared with transtibial technique but the mean elongation was less. The reason might be because of the different techniques and the study was done with porcine knees which are different from human [64].

The mean meniscal extrusion, functional outcome, degree of cartilage loss and healing rate were comparable between these 2 techniques. The factor that significance effected the degree of cartilage loss was the healing status of the meniscal root. Complete healing showed significantly less cartilage loss compared with partial healing and no healing [27].

#### *6.2.2.3 All inside technique (other than suture anchor)*

This was another technique using for medial meniscus root repair. This technique was less popular when compared with other techniques because it depended on the condition of the meniscal tissue. This technical step was to suture the torn meniscus together with an all inside meniscus fixator device and may add a suture to the posterior capsule. This technique was suitable for tearing of the meniscus root which there was enough remnant for suturing and good tissue quality (**Figure 13**).

#### **Figure 13.**

*Schematic drawing showed all-inside repair of the medial meniscus root with all-inside meniscal repair devices. Two horizontal stitches were used to repair the torn meniscal tissue together and one vertical stitch was used to repair the posterior capsule.*

This technique provided a better functional outcome, lower progression rate of osteoarthritis, and lower conversion rate to total knee replacement compared with nonoperative treatment at a minimum of 2 years follow up [43].

Another all inside technique that was proposed by Zhu S., was using all the inside meniscus fixator device to non-anatomic repair the torn meniscus root to the posterior capsule. In contrast with previous biomechanics study, this non –anatomic repaired yielded an excellent outcome and a high rate of meniscus healing [65].

#### *6.2.3 Reduction or centralization of medial meniscus extrusion*

As mentioned above, the meniscal extrusion might not reduce after meniscal root repair regarding of technique. Thus, there were many techniques adding to the repair procedure to prevent meniscus displacement during flexion and extension of the knee [66–68]. There was a study of centralization the meniscus in rat knee by Ozeki et al. The study concluded that centralization improved the medial meniscus extrusion and delayed cartilage degeneration [69]. Centralization or reduction of extruded meniscus was still debatable. The mechanics and tension of the meniscus that changed might reflect pain and stiffness after doing the procedure.

From the available treatments mentioned above, the only treatment that could prevent the progression of the osteoarthritis and reduce the rate of knee replacement surgery was medial meniscus root repair [7, 42–46]. In addition, meniscal root repair had better long term functional outcome compare with nonoperative treatment and meniscectomy [42]. However, the result of the repair depended on multiple factors. To achieve the best result, all the necessary conditions must be presented. In systematic review from Jiang et al. in 2019, the bad prognostic factors for medial meniscus root repair were obesity, increasing age, advance osteoarthritis (KL III-IV), and varus malalignment >5o [70]. Therefore, the repair should preserve for patient who had medial meniscus posterior root tear without these conditions. For meniscectomy, the advantages of this procedure over the repair is the immediate pain relief, no need for special rehabilitation program, and could be done regardless of degree of osteoarthritis change. The present of a mechanical symptom such as "locking" was a good candidate for this procedure. The nonoperative treatment of medial meniscus posterior root tear was suitable for patients whose conditions were unfavorable for surgery and could not follow the post-operative protocol. The progression of osteoarthritis were high in both nonoperative and meniscectomy treatment [42].

The available treatments of medial meniscus posterior root tear with their advantages, disadvantages, and results concerning the development of osteoarthritis are summarized in **Table 2**.
