Meniscal Root Repair Along with Auxiliary Procedures for Joint Preservation: Current Concepts

Abstract

Meniscal root repair and joint preservation surgeries have gained increased interest in the last decade, from a better interpretation of the role of meniscal functions, from the biomechanical studies. Several published results from both biomechanical and clinical studies has proven the effectiveness of meniscal root repairs and has led to a unanimous international consensus for the need for root repair surgery. Meniscal repair by suture pull-out technique is widely followed around the world and leads to adequate healing and good clinical outcome. There are auxiliary procedures like centralization sutures (to reduce the meniscal extrusion), high tibial osteotomy, cartilage repair procedures, meniscal root reconstruction and ligament reconstructions are performed along with meniscal root repair, especially in the younger patients and recently sub-chondroplasty for the bone marrow lesions (BMLs) are also executed. This review article discusses the anatomy, types of root tears, evaluation, treatment, outcomes of root repair, and the need for additional procedures, which are imperative for joint preservation and restoration of the biomechanics of the knee.

Introduction

Meniscal root tears and extrusion of the meniscus was described as early as in 1991 by Pagnani et al. [1] and has been considered as one of the prognostic factors for the development of osteoarthritis. Meniscal root tears and posterior horn radial tears are located within 1 cm of its original footprint or avulsed with bony fragment/soft-tissue peel-off kind of root avulsion [2]. The prevalence of posterior root tears, that are identified during knee arthroscopy has been reported to be 7–9%, in which the majority (2/3rd) of the cases were found to be from medial meniscus [3, 4]. Allaire et al. [5] showed that medial meniscus root tear would resemble a complete meniscectomised knee, due to abnormal high-peak tibiofemoral contact pressures and decreased contact areas. Further, association of root tear–meniscal extrusion and degenerative cartilage damage, with increased tibiofemoral stresses during axial loading are at biomechanical disadvantage for the knee joint. There are two techniques for meniscal root repair—suture anchors repair and trans-tibial suture pull-out technique (single tunnel/double tunnel). Various authors have demonstrated that meniscal root repair has restored the knee function and kinematics, better patient outcomes, and decreased healthcare expenditures. Thus, meniscal root repair is imperative for restoration of knee functions and are more prevalently adopted in modern-day practice [2, 6, 7]. However, meniscal extrusion correction after root repair is still unanswered and controversial, which necessitates additional procedure to address this issue. Moon et al. [8] have reported that meniscal extrusion progresses despite successful repair. The various factors like elderly patients, females, higher BMI, increased KL grade of osteoarthritis scale, varus aligned mechanical axis angle of the lower limb, and lesser sports participation are risk factors for root tears [9] and are predictors for inferior outcome [8]. Knee joint preservation not only depends on meniscal root attachment but also on the interplay of various factors that conglomerate in the eventual progression of arthritis. Adequate correction of Meniscal extrusion following root repair is controversial and necessitates additional procedure to address this issue. This review article discusses brief anatomy, biomechanics, and various techniques for root repair along with the need for supplementary procedures, to address extrusion correction, alignment correction, and cartilage repair techniques.

Medial Meniscal Root Anatomy and Biomechanics

The meniscal tissue is a fibrocartilaginous wedge-shaped disc-like collagen construct, which acts as a shock absorber by distributing the force through circumferential hoop stresses. From cadaveric studies, the footprint attachments of both the meniscal [10, 11] tissue are shown in Table 1. Biomechanical studies have demonstrated that the meniscal roots dissipate the axial loads as hoop stresses and aids in the absorption of 50–70% of the loads by the meniscus in medial and lateral compartments of the knee [5, 12]. Hence, loss of hoop stresses imparts high loads on the articular cartilage of the knee during normal physiological activities. This decreased tibiofemoral contact area, and increased peak contact pressures across the joint surface are similar to that of a total meniscectomised knees [5].

Table 1.

Schematic image showing meniscal root anatomy and location of the root attachments

Classification

The most widely used classification is LaPrade types of root tear [13], where he categorized meniscal root tears into Type 1—partial and stable type of root tears; Type 2—complete/radial tears which are within 9 mm of the bony root attachment and type 2 are further subclassified into types 2A, 2B, and 2C, based on the location of 0–3 mm, 3–6 mm, and 6–9 mm from the root attachment, respectively; Type 3 are bucket-handle tears with a complete root detachment; Type 4—complex oblique tears with complete root detachments extending into the root attachment; and Type 5—are bony avulsion fractures of the meniscal root attachments (Fig. 1). Recently, Kim et al. [14] have classified root tears based on displacement and tear gap. From arthroscopic assessment and measurement of tear configuration, he classified root tears into 5 types based on the type of tear and the measured tear gap: type 1—incomplete root tear; type 2—complete root tear with no gap or undisplaced; type 3—complete root tear with tear gap of 1–3 mm; type 4—complete root tear with a gap of 4–6 mm; and type 5—complete root tear with a gap of 7 mm. By this classification, he had demonstrated from clinical data that a higher Kim-type root tears (increasing displacement of the tear gap in arthroscopic surgery) were associated with increased meniscal extrusion, severe chondral wear, and higher grade of osteoarthritis [14].

Fig. 1.

Laprade classification of root tear and tear configuration in MRI axial, coronal, sagittal sections, 2a–c shows MRI images of Laprade type 1 (2b arrow shows small linear signal), 2d–f shows MRI image of Laprade type 2 (2e shows a cleft sign, 2f shows ghost sign), and 2h–j shows MRI image of Laprade type 3 (linear signal changes seen within the body and posterior horn). 2k–m Shows Laprade type 4 (oblique signal near root attachment), 2n, o shows Laprade type 5 (bony avulsion fragment). (Permission obtained from LaPrade CM [13] for use of pictorial representation of root tear types—AJSM-2015 and MRI representation of different root tear types are example cases from our institute)

Clinical Manifestation

The two types of clinical presentations of root tears are traumatic and degenerative root tears. Post-traumatic root tears are seen in young adults (sports injuries or road traffic accidents). Whereas, degenerative root tears are typically seen in middle-aged adults (especially females), obese patients, and sedentary homemakers. They present with a sudden catching pain or a sharp snap in their knees following low-velocity twisting injuries during descending from stairs while boarding a high step in a bus or auto-rickshaw or while walking on a slippery surface. Sitting on the floor with crossed leg position is a routine practice in the Asian population to eat meals in a kneeling or squatting position [15]. Generally, degenerative meniscus root tears lack a traumatic event, a high degree of clinical suspicion is required when assessing the patient with atraumatic knee pain, especially with respect to medial meniscus. The commonest risk factors are Varus aligned lower limb, old age, increased body mass index (BMI), female sex, and increased Kellgren–Lawrence grade [9]. Clinical findings associated with meniscal root tears are joint line tenderness (especially over the medial and posteromedial aspect), pain during full knee flexion, positive McMurray test [16] and with or without severe tenderness in proximal medial tibial condyle due to stress syndrome from varus aligned knee.

Imaging

Radiographs including weight-bearing radiographs–anteroposterior (AP) view, lateral (LAT) view, standing AP with 45° of knee flexion (Rosenberg view), and merchant views are routinely taken. The radiographic assessment helps to quantify medial compartment arthritis using Kellgren–Lawrence (KL) grade. Long leg alignment films are also mandatory to assess the mechanical axis and malalignment (Fig. 2b). Medial meniscal posterior horn root tear (MMPRT) is diagnosed from specific magnetic resonance imaging (MRI) findings and best assessed using T2-weighted sequences. The pathognomonic findings on MRI include the absence of a normal meniscal jet-black signal or a high signal replacing the normal dark meniscal signal (ghost sign) in the sagittal section, a vertical linear defect (truncation sign/cleft sign) at the meniscus root in the posterior coronal section, or a radial linear defect in the posterior aspect in the axial sections [17]. Meniscal extrusion is defined as a substantial outward displacement (> 3 mm for medial tears) of the meniscus from the tibial articular cartilage and its indirect evidence of posterior horn root tear. It is also possible to determine the Laprade types of the root tears from the careful examination of the MRI scans in all the three sections axial, sagittal, and coronal (Fig. 1). MRI assessment is necessary to know the tear morphology, classification of tears, amount of extrusion, cartilage status, bone marrow lesions (BMLs), and ligament status. Postoperative MRI is useful for the assessment of correction of extrusion, healing status, and tunnel position (Table 2).

Fig. 2.

A patient with root tear and varus aligned knee: a preoperative weight-bearing clinical image, 4b preoperative alignment X-ray showing varus of 9°, 4c–f arthroscopic images showing root repair with two fiber wires in cinch-type suture configuration, 4g, h high tibial osteotomy of the fluroscopy image and intraoperative picture showing wedge plate and suture disc were fiber wires are tied over it, 4i postoperative alignment X-ray showing correction of varus from 9 to 2.6°, 4k, j 6 month postoperative MRI images showing adequate healing, 4l 6 month follow-up clinical picture after correction

Table 2.

MRI findings in different sections showing healing status of the meniscus

Prognosis

It is known that meniscal root tear behaves functionally similar to complete meniscectomised knee and eventually leads to osteoarthritis due to higher peak contact stress across the opposing articular surfaces. It is reported that 28% of patients with root tear eventually undergo total knee arthroplasty (TKA) [5]. Recently, the association of root tear with meniscal extrusion and spontaneous osteonecrosis of the knee (SONK) has also been the subject of ongoing investigation [18, 19]. Yasuda et al. [20] found that root tears can predispose to extrusion of meniscus, SONK, and degeneration of cartilage. Hence, along with the root repair, its imperative that extrusion is also corrected during the surgical intervention. Although root repair has shown to decrease the progression of osteoarthritis and conversion to arthroplasty, various underlying factors like, sub-chondral bone status, extrusion correction, Cartilage repair procedures, alignment corrections knee ligament stability interplay in determining the success of root repair procedures. Krych et al. [21], in his study of failed cartilage repair surgery found that the most commonly recognized reason for failure was untreated malalignment. He concluded that, the majority of failures were attributed to untreated background factors such as malalignment, meniscal deficiency, and instability. The stepwise approach of considering and addressing alignment, meniscal volume, and stability remains essential in joint preservation and restoration procedures.

Philosophy of Management

The medial meniscal root repair surgeries are advocated in relatively young patients with an otherwise healthy knee and with concurrent assessment of alignment, cartilage, bone marrow lesions and ligamentous factors because failure to address these underlying pathology has been demonstrated to be one of the most common reasons for revision after knee preservation surgery [21] Specific indications for the meniscal repair consist of acute tears and chronic/degenerative tears in active patients with lower grade osteoarthritic changes (ie, Kellgren-Lawrence grade #2). Contraindications to meniscal root repair include subchondral bone collapse, Bone on bone radiological appearance on weight bearing x-rays and notable degenerative pathology of the affected knee compartment, which must be comprehensively assessed at the time of presentation. Further, increased BMI ie, 30 kg/m2) are relative contraindications as they lead to increased stress on the repair construct [22]. Partial meniscectomy has a role in patients with irreparable tears and in patients with the mechanical symptoms such as locking or pain, where the trial of non-surgical management and physical therapy has been tried. Concurrent pathologies that need to be are addressed—alignment correction, cartilage repair techniques, and ligament reconstructions. Recently, one of the causations of pain has been attributed to bone marrow lesions (BMLs), for which few authors have advocated subchondroplasty [23, 24]. Root repair can be combined with all these procedures with proper patient selection, correct indication, and diligent surgical expertise.

Root Repair Techniques

The two prevalent methods of root repair are suture anchor fixation and trans-tibial suture pull-out techniques. Kim et al. [16] in 2011 have compared these two techniques, and reported that both techniques showed significant and similar reductions of medial root to its native attachment with similar meniscal extrusion correction and structural healing. The different suture configurations for the root repair have been described, simple sutures, locking loops, and suture cinch loops commonly [25]. Biomechanical studies have shown that the cinch loop has better locking loop strength than simple suture configurations [26]. Furthermore, these studies revealed that it has increased pull-out strength than standard simple suturing methods. Feucht MJ et al. [27] evaluated various suture materials in porcine menisci, comparing biomechanical properties, and concluded that FiberWire (Arthrex) may be the preferred suture material for transtibial pull-out MMPRT repair due to comparably low displacement during cyclic loading and higher values for maximum stiffness and load. The 2 mm FiberTape (Arthrex) exhibited greater displacement, but this was a maximum of 1.46 mm, the clinical significance of which is unknown. Suture pull out can be done with Single trans-tibial tunnel or with double tunnel. LaPrade et al. [28] have described the technique of double tunnel pull-out repair of the medial meniscus root, and have reported improvement in pain, function, and activity level. Tapasvi et al. [29] described the knotless medial meniscus posterior root repair which obviates the need for the trans-tibial tunnel. In his technical note, he has discussed based on Feucht MJ et al [27] observation that, the suture anchor construct provides significantly lower displacement and higher stiffness, favorable biomechanical properties, better healing advantages of the root and better restoration of knee function. Enu et al. [30] from his technique of knotless suture anchor repair the medial meniscal root repair has shown decreased operative time improved Lysholm scores and decreased extrusion on MRI. Authors’ preferred technique is Cinch loop configuration and single tunnel trans-tibial pull-out technique.

Auxiliary Procedures Along with Root Repair for Joint Preservation

With the proper patient selection, a complete assessment of knee with weight-bearing X-rays, and alignment scanogram of both the lower limb and MRI evaluation, auxiliary procedures can be chosen and customized to patient’s pathology (Fig. 3). MRI assessment is vital for identifying and choosing the right patients for these auxiliary procedures and for optimum outcomes. Clinical factors (non-modifiable) also need to be considered before opting for these additional procedures like age of the patients, time to presentation/duration of symptoms, mode of injury, the activity level of the patients (athlete/recreational sportsman/sedentary worker/homemaker), and BMI. These factors are important for the prudent selection of the additional procedures along with root repair. Following procedures can be chosen in isolation with root repair or a combination of procedures can be considered for a properly selected patient.

Fig. 3.

Treatment algorithm for selection of auxililary procedures (single/combination) along medial meniscus root repair

Root Repair with Centralization Sutures

Root repair with centralization sutures is advocated for patients with higher age group, with longer duration of symptoms and have a larger meniscal extrusion in their preoperative MRI scans. Increased meniscal extrusion in postoperative magnetic resonance imaging (MRI) scans [31, 32] has been reported in various studies. The systematic review of root repair articles concluded that correction of meniscal extrusion was obtained in only 56% of patients [33]. Daney et al. from his cadaveric study have found out that anatomic repair augmentation with a centralization suture has resulted in significant correction of the extrusion and suggested that it could be beneficial for chronic repair and better long-term prognosis [34]. However, he has not given the cut-off value (extrusion distance), for the need of centralization sutures as it was a cadaveric study. There is no available consensus for the indications of this procedure and no quantification value of  extrusion distance that needs this additional procedure. Kaplan et al. [32] in his study found that no patients with > 3 mm of pre-operative meniscal extrusion on MRI had adequate extrusion correction. Preoperative meniscal extrusion greater than 3 mm was considered significant and suggested all-inside centralization sutures by Chernchujit et al. [35]. The Chernchujit et al. [36] in a surgical technical note have described the arthroscopic direct meniscal extrusion reduction (ADMER) as a surgical tip to reduce persistent meniscal extrusion in medial meniscal root repair. Techniques for root repair with centralization sutures are given by various authors [35, 37]. Our preferred technique is arthroscopic root repair—single tunnel suture pull-out technique with centralization sutures from the suture anchor (Fig. 4f,g,h).

Fig. 4.

Preoperative and post-operative radiographs, with Arthroscopic images of root repair patient where—single tunnel suture pull-out technique with centralization sutures and ACL reconstruction. 8a, shows preoperative alignment of around 2 degrees in lower limb scanogram X-ray, 8b, c MRI images show ACL tear and root tear, 8d, e showing meniscus root tear and extrusion after root repair, 8f shows suture anchor insertion at medial end of the tibial plateau for the centralization procedure, 8g, h meniscal centralization suture being typed, 8i shows ACL reconstruction, 8j shows postoperative X-ray (thick solid arrow shows suture anchor for centralization, thin solid arrow shows bioscrew for tibial fixation in ACL reconstruction, thin dotted arrow shows suture disc for root repair suture, and thick dotted arrow shows tight-rope button for femoral fixation of graft in ACL reconstruction)

Root Repair with HTO

The repair of MMPRT in the varus aligned knee is controversial and the amount of varus deformity that needed correction varies in different parts of the world. Hwang et al. in his study have found that root tear patients had significant varus of (4.5° ± 3.4°) compared with other patients (2.4° ± 2.7°; P < 0.01) [9]. Jing et al. [38] in his study have considered high tibial osteotomy (HTO) alongside root repair for all the patients having Varus more than 4°. Nakamura et al. [39] suggested that root repair can be combined with the open-wedge high tibial osteotomy (OWHTO) and centralization suture as a single-stage procedure (Table 3). He has stated various advantages—the anchor for centralization procedure would distribute the hoop tension at the root repair site and the repaired meniscus can be spared from weight-bearing by the load-shifting effect of the OWHTO [39]. We recommend combined root repair with HTO for all patients with varus of more than 5°. Our technique is OWHTO by the medial approach over the proximal tibia, and then arthroscopic assessment of the root tear with tying of two cinch loops and bring out the sutures through the trans-tibial tunnel. Advantages of the release of superficial MCL during HTO aid in the opening of medial joint space and easier repair of the meniscal root. The surgical pearl for combined osteotomy and the trans-tibial tunnel is by taking the osteotomy cut slightly lower will accommodate the trans-tibial tunnel in the proximal fragment (Fig. 2). However, all inside root repair can be combine with the OWHTO and centralization suture, as suggested by Nakamura et al. [39]

Table 3.

Various studies that has recommended different auxiliary procedures along with root repair

Studies	Type of study	Auxiliary procedure	Recommendation/advantages
Daney et al. (2019) [34]	Cadaveric study	Root repair + centralization suture	The anatomical trans-tibial suture pull-out root repair with centralization techniques are accountable for better restoration of knee contact mechanics and meniscal extrusion correction when compared with isolated root repair and nonanatomic repair
Chernchujit et al. (2018) [36]	Technical note	Root repair + centralization suture	Arthroscopic direct meniscal extrusion reduction (ADMER) technique is a surgical advantage to reduce persistent meniscal extrusion in posterior meniscal root repair
Jing et al. (2020) [38]	Case series	Root tear + OWHTO	A higher healing rate of MMPRT can be obtained using all-inside repair and regeneration of articular cartilage in the medial condyles with Medial OWHTO
Nakamura et al. (2018) [39]	Technical note	Root repair (suture anchor repair) + centralization suture + OWHTO	Suture anchor repair for an MMPRT combined with arthroscopic meniscal centralization and OWHTO, provides better outcome and have a technical advantage
Bancha Chernchujit et al. (2017) [41]	Technical note	Root repair for both menisci (lateral and medial meniscus) + ACL reconstruction	Advantages of his technique—(a) systematic approach is required to address combined medial–lateral meniscal root tears with ACL rupture, (b) effective and lesser operative time, (c) minimal iatrogenic meniscal injury (only 1 bite), (d) prevention of “cut-through” (larger-width material) by his technique, (e) creates good visualization for the injured structures, (f) creates step-by step landmarks for anatomic attachment of the injured structures
Xue et al. (2018) [42]	Case report	Root tear + PCL reconstruction	Advantages of his technique: (a) standard arthroscopic portals for PCL reconstruction without additional incision; (b) the “U” shape suture technique increases the contact surface between the posterior root stump and bone surface, which is favorable for good healing; (c) the shared tunneling technique avoids additional bone tunnel which may influence the bone tunnel for PCL reconstruction; (d) stronger fixation

Root Repair with Cruciate Ligament (ACL/PCL) Reconstruction

Middle-age patients are susceptible for root tear along with the ACL/PCL tear following trauma or domestic fall. Ligament injury and root tear are bad combination injuries from biomechanical function of the knee, which would otherwise would hasten the progress of osteoarthritis. Medial meniscus root tears in middle-aged women are often degenerative tears, however, can be also be seen in an acute traumatic setting, especially associated with knee ligament injuries [9, 40]. To address root tear and ACL tear simultaneously has been debated, and no consensus exists on the surgical procedure. Bancha Chernchujit et al. have proposed a technique to manage posterior root tear with ACL rupture [41]. He has listed out various advantages to address both simultaneously explained in Table 3. Our preferred technique is a suture pull-out technique for root tear with centralization sutures with a suture anchor and simultaneous ACL reconstruction with a hamstring tendon graft. Here, tunnel coalescence can be avoided by adjusting the tibial jig angle difference by 5°–10° for ACL tibial tunnel and root repair tunnel. Furthermore, the tunnel for root repair is drilled first and entry is taken medial in the proximal tibia. This ensures a separate tunnel for the combined procedure. Xue et al. [42] have described a U-shape suture and shared tunnelling technique for single-stage PCL reconstruction with the posterior root of medial meniscus root repair.

Root Repair with Cartilage Repair and Sub-chondroplasty

Cartilage lesion can be due to trauma/degenerative, which results in a focal chondral or osteochondral defect, or diffuse loss of articular cartilage as seen in osteoarthritis. Most often degenerative meniscal root tear can be associated with cartilage defect of various size. The established cartilage repair methods were developed for focal traumatic defects, most frequently in an otherwise healthy joint. Those methods also have limited application in early degenerative joints, such as those with chronic instability and meniscal loss [51]. Lesions in a degenerative environment have much less healthy surrounding cartilage, and the cartilage thickness surrounding such a lesion varies substantially. There is no single technique that can address all types of cartilage lesions and through MRI evaluation with cartilage sequence of both cartilage lesion and surrounding normal cartilage is very important before considering treatment for early cartilage lesions. The cartilage repair techniques for early OA are bone marrow stimulation techniques (microfractures), bone marrow augmentation techniques like scaffold-based cartilage repair techniques [43], autologous chondrocyte implantation (ACI) [44, 45], osteochondral allograft transplantation (for larger defects) [46, 47], and bone marrow-derived mesenchymal stem cells (BM-MSCs) [48] are the various options have been proposed by different authors. The selection of cartilage repair technique depends not only on the size of the lesion but also on the age of the patient, contained lesion/non-contained lesion, diffuse lesion/focal lesion with shouldering edge, and normal surrounding cartilage and cartilage health/quality of the cartilage matrix (can be determined by 3 T-MRI cartilage mapping). All the above cartilage repair techniques can be combined with root repair and other auxiliary procedures. Different surgical options have been proposed to treat articular cartilage defects, and choice of the repair techniques varies in a different part of the world. Bekkers in his systematic review concluded that lesions > 2.5 cm² can be treated with osteochondral autologous transplantation or ACI and the smaller lesions (< 2.5 cm²) could be treated with microfracture [49]. Our preferred technique is root repair and microfracture for the cartilage lesions. Isolated cartilage lesions are often related to subchondral bone marrow lesions (BMLs) [51].

Dore et al. [50] suggested that bone marrow lesions (BMLs) and cartilage defects are inter-related [51] and may have a key role in cartilage volume loss. He insisted that both cartilage defects and bone marrow lesions should be considered targets for intervention. Cohen et al. [52] in his study had reported the results of the use of calcium phosphate injection into subchondral bone, for bone marrow oedema, especially for athletes and patients who are awaiting knee arthroplasty [52, 53]. Bonadio et al. [23] recommend sub-chondroplasty for BMLs and concluded that it provides a significant improvement in pain and functional capacity in the short-term. Biologic treatment of BMLs with bone marrow aspirate concentrate (BMAC) and injectable demineralized bone matrix (iDBM) are an effective adjunct to arthroscopy that provides short-term pain relief [54]. Levy et al. [55] in 2020 published his series of 179 patients, who underwent subchondral calcium phosphate injections (sub-chondroplasty). He concluded that the treatment of BMLs is highly successful in decreasing pain, improving function, and expediting return to work. We do not have experience of treating BMLs with sub-chondroplasty. However, from the current literature (Table 4), various auxiliary procedures with root tear can be combined in early osteoarthritis patients in carefully selected patients.

Table 4.

Results of root repair from various studies that were published in last 4 years and their inferences

Article	Study group	Mean follow-up	Meniscus	Radiographic outcomes	Clinical outcomes	Conclusion
LaPrade et al. (2017) [28]	Pull-out repair of lateral (14) vs medial (31)	24 month (minimum)	Both	Not reported	Significant improvement in Lysholm, WOMAC, SF-12, and Tegner in the both the groups. No significant difference between groups	Lateral meniscal tear had 8 times the odds of undergoing concomitant ACL reconstruction. All failures (6.7%) occurred with medial meniscal tears and in patients < 50 years old
Krych et al. (2018) [57]	Meniscectomy (26) vs conservative (26)	66 months	Medial	No significant difference in progression of K–L grade between groups	No significant difference in follow-up Tegner or IKDC scores, progression to arthroplasty, or overall failure rate	Female sex, BMI > 30, and meniscal extrusion greater than 3 mm associated with worse outcomes. Partial meniscectomy provides no additional benefit
Chung et al. (2017) [58]	Meniscus repair-increased extrusion (23) vs decreased extrusion (16)	69.8 months	Medial	No significant progression of K–L grade in patients with decreased extrusion Significantly greater progression of OA in patients with increased extrusion	Significantly higher postop Lysholm and IKDC score in patients with decreased extrusion	No significant difference in meniscal healing between groups. Increased extrusion has poor outcome and progression of OA, which warrants needs for additional procedure
Keyhani et al. (2018) [59]	Suture anchor repair (40) vs conservative (33)	24 months (minimum)	Lateral	Not reported	Functional results (IKDS and LKS) at 12- and 24-month follow-up were similar between the two groups (all P > 0.05)	All patients underwent concomitant ACL reconstruction. Functional outcomes of repairing root avulsion and para-root tear with those whose posterior root tear was left untreated are similar in short-term follow-up; however, as the time passes, the sports activity level and mid-term subjective outcomes may worsen in patients whose root tear was left untreated
Furumatsu et al. (2019) [60]	Repair, FasT-Fix vs FasT-Fix Modified Mason Allen (F-MMA)	12 months	Medial	Not reported	F-MMA had better second-look arthroscopic score (7.2 vs 6.0). Significant improvement in Lysholm, IKDC, and VAS for both groups. F-MMA group had better postoperative (VAS) pain score, KOOS pain, and sports/rec scores	F-MMA suture configuration showed better meniscal healing and superior clinical outcomes compared with single FasT-Fix repairs in patients with medial meniscal root tears. These results suggest that the F-MMA pull-out repair may possibly reduce knee pain in arthroscopic root repair
Lee et al. (2019) [61]	Progression to TKA post-meniscectomy vs no progression to TKA post-meniscectomy	60 months (minimum)	Medial	Varus alignment, presence of radiographic arthritis, and greater K–L grade at baseline (2–3) significantly more associated with progression to TKA post-meniscectomy	Older age and greater BMI associated with significantly greater progression to TKA	Patients with no TKA still had significant progression of radiographic arthritis 2 years and at last follow-up (mean 8.9 years). Arthroscopic meniscectomy is an effective treatment for degenerative root tear, with favorable long-term survival in well-aligned nonarthritic knees. However, meniscectomy should be cautiously advocated in patients with varus alignment and preoperative radiographic osteoarthritis

Root Reconstruction with Gracilis Autograft

In challenging scenarios like chronic meniscal root tears with > 5–7 mm retraction, a complex radial tear in posterior horn, long-standing degenerated root stump, failed anatomical root repairs, and in revision root repair cases, root reconstruction with Gracilis autograft is a valuable salvage technique that can be considered. This bailout technique was popularised by Lee et al. [56] in 2017.

Conclusion

Meniscal root repairs are necessarily done in well-selected patients and in lower osteoarthritic knees. Trans-tibial suture pull-out root repair technique yields a strong construct and a simpler arthroscopic technique, providing established and positive long-term outcomes. We recommend meniscal root repair, along with other auxiliary procedures for coexisting pathologies that can be seen in degenerative joint disease. When indicated, various auxiliary procedures can be combined with root repairs (single stage procedure) as a joint preservation tool.

Compliance with Ethical Standards

Conflict of interest

The authors declares that they have no conflict of interest.

Ethical Standard Statement

This article does not contain any studies with human or animal subjects performed by the any of the authors.

Informed Consent

For this type of study informed consent is not required.