Early Osteoarthritis After Untreated Anterior Meniscal Root Tears: An In Vivo Animal Study

Inflammatory synovial biomarkers and state of the tibiofemoral joint in the post-surgical settings: a narrative review

Background and Objective

Knee surgery attempts to restore the native biomechanics of the knee, improve stability, and decrease the progression of osteoarthritis (OA). However, despite improvements in surgical techniques, tissue degradation and OA are common after knee surgery, occurring in higher rates in surgical knees compared to non-surgical knees. The aim of this study is to analyze previous literature to determine which synovial fluid biomarkers contribute to knee tissue degradation and decrease patient outcomes in the post-surgical setting of the knee.

Methods

A narrative review of relevant literature was performed in July 2023. Studies reporting on synovial biomarkers associated with the post-surgical knee were included.

Key Content and Findings

The literature reported that proinflammatory synovial biomarkers cause cartilage degradation and turnover which eventually leads to OA. The associated biomarkers are typically present prior to physical symptoms so understanding which one's correlate to OA is important for potential therapeutic treatments in the future. Studying the preoperative, early postoperative, and late postoperative synovial biomarkers will allow physicians to develop an improved understanding of how these biomarkers progress and correlate to knee tissue degradation and OA. This understanding could lead to further developments into potential treatment options. Research into inhibiting or reversing these inflammatory biomarkers to slow the progression of knee tissue degradation has already begun and has reported some promising results but is currently limited in scope.

Conclusions

Synovial fluid biomarkers in the post-surgical knee setting may contribute to decreased patient outcomes and the progression of knee tissue degradation. There is no current consensus on which of these biomarkers are the most detrimental or associated with decreased patient outcomes. With an improved understanding of the individual biomarkers, potential personalized therapeutic treatment could be used by physicians in the future to improve patient outcomes after surgery.

Subchondral bone remodeling patterns in larger animal models of meniscal injuries inducing knee osteoarthritis - a systematic review

PURPOSE

Elucidating subchondral bone remodeling in preclinical models of traumatic meniscus injury may address clinically relevant questions about determinants of knee osteoarthritis (OA).

METHODS

Studies on subchondral bone remodeling in larger animal models applying meniscal injuries as standardizing entity were systematically analyzed. Of the identified 5367 papers reporting total or partial meniscectomy, meniscal transection or destabilization, 0.4% (in guinea pigs, rabbits, dogs, minipigs, sheep) remained eligible.

RESULTS

Only early or mid-term time points were available. Larger joint sizes allow reporting higher topographical details. The most frequently reported parameters were BV/TV (61%), BMD (41%), osteophytes (41%) and subchondral bone plate thickness (39%). Subchondral bone plate microstructure is not comprehensively, subarticular spongiosa microstructure is well characterized. The subarticular spongiosa is altered shortly before the subchondral bone plate. These early changes involve degradation of subarticular trabecular elements, reduction of their number, loss of bone volume and reduced mineralization. Soon thereafter, the previously normal subchondral bone plate becomes thicker. Its porosity first increases, then decreases.

CONCLUSION

The specific human topographical pattern of a thinner subchondral bone plate in the region below both menisci is present solely in the larger species (partly in rabbits), but absent in rodents, an important fact to consider when designing animal studies examining subchondral consequences of meniscus damage. Large animal models are capable of providing high topographical detail, suggesting that they may represent suitable study systems reflecting the clinical complexities. For advanced OA, significant gaps of knowledge exist. Future investigations assessing the subchondral bone in a standardized fashion are warranted.

Improved tibiofemoral contact restoration after transtibial reinsertion of the anterior root of the lateral meniscus compared to in situ repair: a biomechanical study

PURPOSE

To compare biomechanical behaviour of the anterior root of the lateral meniscus (ARLM) after a transtibial repair (TTR) and after an in situ repair (ISR), discussing the reasons for the efficacy of the more advantageous technique.

METHODS

Eight cadaveric human knees were tested at flexion angles from 0° to 90° in four conditions of their ARLM: intact, detached, reinserted using TTR, and reinserted using ISR. Specimens were subjected to 1000 N of compression, and the contact area (CA), mean pressure (MP), and peak pressure (PP) on the tibial cartilage were computed. For the TTR, traction force on the sutures was registered.

RESULTS

ARLM detachment significantly altered contact biomechanics, mainly at shallow flexion. After ISR, differences compared to the healthy group persisted (extension, CA 22% smaller (p = 0.012); at 30°, CA 30% smaller (p = 0.012), MP 21%, and PP 32% higher (both p = 0.017); at 60°, CA 28% smaller (p = 0.012), MP 32%, and PP 49% higher (both p = 0.025). With TTR, alterations significantly decreased compared to the injured group, with no statistical differences from the intact ones observed, except for CA at extension (15% decrease, p = 0.012) and at 30° (12% decrease, p = 0.017). The suture tension after TTR, given as mean(SD), was 36.46(11.75)N, 44.32(11.71)N, 40.38(14.93)N, and 43.18(14.89)N for the four tested flexion angles.

CONCLUSIONS

Alterations caused by ARLM detachment were partially restored with both ISR and TTR, with TTR showing better results on recovering CA, MP, and PP in the immediate postoperative period. The tensile force was far below the value reported to cause meniscal cut-out in porcine models.

Medial Meniscus Posterior Root Repair Reduces but Does Not Avoid Histologic Progression of Osteoarthritis: Randomized In Vivo Experimental Study in a Rabbit Model

BACKGROUND

The optimal treatment option for meniscus root tears is still challenging, and whether the meniscus root repair ultimately can arrest or delay osteoarthritic changes is still a concern.

PURPOSE/HYPOTHESIS

The purpose of this study was 2-fold: (1) to describe and compare histopathologic findings of 3 different therapeutic options for medial meniscus posterior root tear: nonoperative management, partial meniscectomy, and meniscus root repair; and (2) to test the hypothesis that meniscus root tears treated nonoperatively predispose to a lower risk of osteoarthritic progression compared with partial meniscectomy.

STUDY DESIGN

Controlled laboratory study.

METHODS

Posteromedial meniscus root tears were carried out in 39 New Zealand White rabbits. Animals were randomly assigned into 3 experimental groups: partial meniscectomy after root tear (PM; n = 13), root tears treated conservatively (CT; n = 13), and transtibial root repair (RR; n = 13). Contralateral limbs were used as healthy controls. The animals were euthanized at 16 weeks postoperatively; tissue samples of femoral and tibial articular cartilage were collected and processed for macro- and microscopic assessment to detect signs of early osteoarthritis (OA). Each sample was histopathologically assessed using the Osteoarthritis Research Society International grading and staging system.

RESULTS

Osteoarthritic changes were the hallmark in all 3 experimental groups. The RR group had the lowest scores for cartilage damage (mean, 2.5; range, 2-3), and the PM group exhibited higher and more severe signs of OA (mean, 16; range, 9-16) compared with the CT group (mean, 5; range, 4-6). The between-group comparison revealed significant differences, as the PM group showed a significantly higher rate of macro- and microscopic osteoarthritic changes compared with the RR (P < .001) and CT (P < .001) groups. The weightbearing area of the medial femoral condyle was the most severely affected, and tidemark disruption was evident in all tissue samples.

CONCLUSION

Meniscus root repair cannot completely arrest the histopathologic progression of knee OA but leads to significantly less severe degenerative changes than partial meniscectomy and nonoperative treatment. Partial meniscectomy leads to the most severe osteoarthritic progression, while stable radial tears left in situ have lower progression compared with partial meniscectomy.

CLINICAL RELEVANCE

Histologic assessment is an essential tool and metric for guiding and understanding osteoarthritic features, providing insight into the disease development and progression. This study provides histopathologic evidence on osteoarthritic progression after medial meniscus posterior root repair. This knowledge can help to set more realistic expectations and can lead to the future development of augmented techniques.

Anterior Root Tear of the Meniscus: A Report of Two Cases

Menisci are crescent-shaped fibrocartilagenous structures that increase the tibiofemoral congruity, act as shock absorbers, and provide secondary anteroposterior stability. The root tears affect the biomechanical integrity of the whole meniscus, simulating a total meniscectomy, which can lead to early degeneration of the joint. Most of the root tears affect the posterior part rather than the anterior root. Very few reports have been described in the literature regarding anterior root tears and repairs. We present two such patients with anterior meniscal root tears, one of the lateral meniscus and one of the medial meniscus.

Significant race and gender differences in anterior cruciate ligament tibial footprint location: a 3D-based analysis

BACKGROUND

The aim of the present study was to identify potential race- or gender-specific differences in anterior cruciate ligament (ACL) tibial footprint location from the tibia anatomical coordinate system (tACS) origin, investigate the distances from the tibial footprint to the anterior root of the lateral meniscus (ARLM) and the medial tibial spine (MTS), determine how reliable the ARLM and MTS can be in locating the ACL tibial footprint, and assess the risk of iatrogenic ARLM injuries caused by using reamers with various diameters (7-10 mm).

PATIENTS AND METHODS

Magnetic resonance images of 91 Chinese and 91 Caucasian subjects were used for the reconstruction of three-dimensional (3D) tibial and ACL tibial footprint models. The anatomical coordinate system was applied to reflect the anatomical locations of scanned samples.

RESULTS

The average anteroposterior (A/P) tibial footprint location was 17.1 ± 2.3 mm and 20.0 ± 3.4 mm in Chinese and Caucasians, respectively (P < .001). The average mediolateral (M/L) tibial footprint location was 34.2 ± 2.4 mm and 37.4 ± 3.6 mm in Chinese and Caucasians, respectively (P < .001). The average difference between men and women was 2 mm in Chinese and 3.1 mm in Caucasians. The safe zone for tibial tunnel reaming to avoid ARLM injury was 2.2 mm and 1.9 mm away from the central tibial footprint in the Chinese and Caucasians, respectively. The probability of damaging the ARLM by using reamers with various diameters ranged from 0% for Chinese males with a 7 mm reamer to 30% in Caucasian females with a 10 mm reamer.

CONCLUSIONS

The significant race- and gender-specific differences in the ACL tibial footprint should be taken in consideration during anatomic ACL reconstruction. The ARLM and MTS are reliable intraoperative landmarks for identifying the tibial ACL footprint. Caucasians and females might be more prone to iatrogenic ARLM injury.

LEVEL OF EVIDENCE

III, cohort study.

TRIAL REGISTRATION

This study has been approved by the ethical research committee of the General Hospital of Southern Theater Command of PLA under the code: [2019] No.10.

Total Knee Arthroplasty After Meniscectomy Is More Likely in Patients With Bicompartmental or Complex Tears

Purpose

To determine the relationship between meniscus tear morphologies, stratified by location and pattern, and knee arthroplasty rates in a commercial insurance population.

Methods

The PearlDiver database was queried for patients ≥35 years old with a meniscus tear of specified laterality and ≥2 years follow-up between 2015 and 2018. Two analyses were conducted with cohorts matched on age, sex, Charlson Comorbidity Index, obesity, osteoarthritis (OA), and treatment (meniscectomy vs conservative): one with equal-sized subgroups by tear location (medial only, lateral only, or both medial and lateral) and another by tear pattern (bucket-handle, complex, or peripheral). The rate of subsequent total knee arthroplasty (TKA) was compared between matched groups.

Results

In total, 129,987 patients (mean age: 57.8 ± 10.5 years) were matched by tear location; 1,734 patients with medial-only tears (4.0%), 1,786 with lateral-only tears (4.1%), and 2,611 with medial plus lateral tears (6.0%) underwent a TKA within 5 years (P < .001). Patients with both medial and lateral tears were 1.55-fold more likely to undergo TKA. In total, 24,213 patients (mean age: 56.0 ± 10.5 years) were matched by tear pattern; 296 patients with bucket-handle tears (3.7%), 373 with complex tears (4.6%), and 336 with peripheral tears (4.2%) underwent TKA (P = .01). Patients with complex tears were 1.29-fold more likely to undergo TKA than patients with bucket-handle tears (P = .002).

Conclusions

In matched cohorts of patients with degenerative meniscus tears, having both medial plus lateral tears conferred a 1.5-fold risk of TKA, whereas complex tears conferred a 1.3-fold risk within 5 years. Specific meniscal tear patterns and locations harbor varying risk in progressing to end-stage knee OA, and these data may help counsel patients about their likelihood of progressing to end-stage OA warranting an arthroplasty procedure.

Level of Evidence

Level III, retrospective comparative study.

Optimization of In Situ Indentation Protocol to Map the Mechanical Properties of Articular Cartilage

Tissue engineering aims at developing complex composite scaffolds for articular cartilage repair. These scaffolds must exhibit a mechanical behavior similar to the whole osteochondral unit. In situ spherical indentation allows us to map the mechanical behavior of articular cartilage, avoiding removal of the underlying bone tissue. Little is known about the impact of grid spacing, indenter diameter, and induced deformation on the cartilage response to indentation. We investigated the impact of grid spacing (range: a to 3a, where a is the radius of the contact area between cartilage and indenter), indenter diameter (range: 1 to 8 mm), and deformation induced by indentation (constant indentation depth versus constant nominal deformation) on cartilage response. The bias induced by indentations performed in adjacent grid points was minimized with a 3a grid spacing. The cartilage response was indenter-dependent for diameters ranging between 1 and 6 mm with a nominal deformation of 15%. No significant differences were found using 6 mm and 8 mm indenters. Six mm and 8 mm indenters were used to map human articular cartilage with a grid spacing equal to 3a. Instantaneous elastic modulus E₀ was calculated for constant indentation depth and constant nominal deformation. E₀ value distribution did not change significantly by switching the two indenters, while dispersion decreased by 5-6% when a constant nominal deformation was applied. Such an approach was able to discriminate changes in tissue response due to doubling the indentation rate. The proposed procedure seems to reduce data dispersion and properly determine cartilage mechanical properties to be compared with those of complex composite scaffolds.

Return to sports after bucket handle medial meniscus tear repair using inside out technique in recreational sports players

The main purpose of our study is to determine the outcomes of bucket handle medial meniscus tears repaired with the inside out technique in recreational sports players, and the return of these to pre-injury sports levels. 41 athletes with medial meniscus bucket handle tear were included in the study. 28 cases were associated with ACL tear while rest were isolated tears. Medial meniscus repair was done exclusively with arthroscopy assisted inside out technique. Lysholm score, IKDC score and Tegner staging were used to evaluate functional status of patients with minimum 1-year follow-up. Data was analyzed using Wilcoxon Matched pairs test, and Friedman test. All patients were examined clinically at regular intervals. Lysholm score and IKDC score showed significant increase in their values. Tegner staging showed no significant change compared to their preinjury game level. On VAS pain scale, there was significant decrease in their pain at regular follow up intervals. 2 patients had re-tears of the repaired medial meniscus. Repairing bucket handle tears of the medial meniscus in recreational sports players with the inside out technique yields good results in terms of clinical and functional outcomes. It successfully allows them to return to sports at 1 year.

Mechanical and Microstructural Properties of Meniscus Roots Vary by Location

BACKGROUND

Despite the growing awareness of the clinical significance of meniscus root tears, there are relatively limited biomechanical and microstructural data available on native meniscus roots that could improve our understanding of why they are injured and how to best treat them.

PURPOSE/HYPOTHESIS

The purpose of the study was to measure the material and microstructural properties of meniscus roots using mechanical testing and quantitative polarized light imaging. The hypothesis was that these properties vary by location (medial vs lateral, anterior vs posterior) and by specific root (anteromedial vs anterolateral, posteromedial vs posterolateral).

STUDY DESIGN

Descriptive laboratory study.

METHODS

Anterior and posterior meniscus roots of the medial and lateral meniscus were isolated from 22 cadavers (10 female, 12 male; mean ± SD age, 47.1 ± 5.1 years) and loaded in uniaxial tension. Quantitative polarized light imaging was used to measure collagen fiber organization and realignment under load. Samples were subjected to preconditioning, stress-relaxation, and a ramp to failure. Time-dependent relaxation behavior was quantified. Modulus values were computed in the toe and linear regions of the stress-strain curves. The degree of linear polarization (DoLP) and angle of polarization-measures of the strength and direction of collagen alignment, respectively-were calculated during the stress-relaxation test and at specific strain values throughout the ramp to failure (zero, transition, and linear strain).

RESULTS

Anterior roots had larger moduli than posterior roots in the toe (P = .007) and linear (P < .0001) regions and larger average DoLP values at all points of the ramp to failure (zero, P = .016; transition, P = .004; linear, P = .002). Posterior roots had larger values across all regions in terms of standard deviation angle of polarization (P < .001). Lateral roots had greater modulus values versus medial roots in the toe (P = .027) and linear (P = .014) regions. Across all strain points, posterolateral roots had smaller mean DoLP values than posteromedial roots.

CONCLUSION

Posterior meniscus roots have smaller modulus values and more disorganized collagen alignment at all strain levels when compared with anterior roots. Posterolateral roots have lower strength of collagen alignment versus posteromedial roots.

CLINICAL RELEVANCE

These data findings may explain at least in part the relative paucity of anterior meniscus root tears and the predominance of traumatic posterolateral roots tears as compared with degenerative posteromedial root tears.

Meniscal Root Tears: A Decade of Research on their Relevant Anatomy, Biomechanics, Diagnosis, and Treatment

A foundational knowledge of the anatomy and biomechanics of meniscal root tears is warranted for proper repair of meniscal root tears and for preventing some of their commonly described iatrogenic causes. Meniscal root tears are defined as either a radial tear occurring within one cm of the root attachment site of the meniscus or a complete bony or soft tissue avulsion of the root attachment altogether. Meniscal root tears disrupt the protective biomechanical function of the native meniscus. Biomechanical analyses of the current techniques for meniscal root repair highlight the importance of restoring menisci to their correct anatomic orientation, thereby restoring their biomechanical function. A comprehensive understanding of the clinical and radiographic presentations of these injuries is critical to preventing their underdiagnosis. The poor long-term outcomes associated with conservative treatment measures, namely, ipsilateral compartment osteoarthritis, warrants the surgical repair of meniscal root tears whenever possible. While excellent patient-reported outcomes exist for the various surgical repair techniques, adherence to stringent post-operative rehabilitation protocols is critical for patients to avoid damaging the integrity of a repaired root. This review will focus on current concepts pertaining to the anatomy, biomechanics, diagnosis, treatment, and postoperative rehabilitation for meniscal root tears.

Biomechanical consequences of anterior root detachment of the lateral meniscus and its reinsertion

Treatment of posterior meniscal roots tears evolved after biomechanical evidence of increased pressures on the tibiofemoral cartilage produced by this lesion and the subsequent accelerated development of arthritis or osteonecrosis observed clinically. However, little is known about the consequences of the detachment of the anterior roots. This in-vitro study analyzes the biomechanical changes in the tibiofemoral joint caused by avulsion of the anterior root of the lateral meniscus. The effectiveness of surgical root re-insertion to restore the pre-injured conditions is also evaluated. Using cadaveric knees at flexion angles from 0° to 90°, results show that the lesion significantly reduces the contact area and raises the pressure on the tibiofemoral cartilage of the injured compartment at all angles. Said modifications become larger at low flexion angles, which are the most frequent positions adopted by the knee in daily and sports activities, where they result similar to total meniscectomy. In-situ repair partially restores the contact biomechanics. Consequently, careful attention should be paid to proper diagnosis and treatment of detached anterior roots since the observed altered knee contact might induce similar degenerative problems in the cartilage as with completely detached posterior roots.

Better Coverage of the ACL Tibial Footprint and Less Injury to the Anterior Root of the Lateral Meniscus Using a Rounded-Rectangular Tibial Tunnel in ACL Reconstruction: A Cadaveric Study

Background

To better restore the anatomy of the native anterior cruciate ligament (ACL) attachment and fiber arrangement, researchers have developed techniques for changing the shape of the ACL bone tunnel during ACL reconstruction.

Purpose

To compare the coverage of the ACL tibial footprint and influence on the anterior root of lateral meniscus (ARLM) between a rounded-rectangular tibial tunnel and a conventional round tibial tunnel for ACL reconstruction.

Study Design

Controlled laboratory study.

Methods

A total of 16 (8 matched-paired) fresh-frozen human cadaveric knees were distributed randomly into 2 groups: a rounded-rectangular tunnel (RRT) group and a round tunnel (RT) group. One of the knees from each pair was reamed with rounded-rectangular tibial tunnel, whereas the other was reamed with round tibial tunnel. Coverage of the ACL tibial footprint and areas of ARLM attachment before and after reaming were measured using 3-dimensional isotropic magnetic resonance imaging.

Results

In the RRT group, the average percentage of ACL tibial footprint covered by the tunnel was 70.8% ± 2.5%, which was significantly higher than that in the RT group (48.2% ± 6.4%) (P = .012). As for the ARLM attachment area, in the RT group, there was a significant decrease (22.5% ± 5.9%) in ARLM attachment area after tibial tunnel reaming compared with the intact state (P < .001). Conversely, in the RRT group, the ARLM attachment area was not significantly affected by tibial tunnel reaming.

Conclusion

Rounded-rectangular tibial tunnel was able to better cover the native ACL tibial footprint and significantly lower the risk of iatrogenic injury to the ARLM attachment than round tibial tunnel during ACL reconstruction.

Circumferential Rim Augmentation Suture Around the Perimeniscal Capsule Decreases Meniscal Extrusion and Progression of Osteoarthritis in Rabbit Meniscus Root Tear Model

BACKGROUND

We recently analyzed the joint capsule adjacent to the medial meniscus and found that the perimeniscal joint capsule has collagen fiber orientation similar to that of circumferential meniscal fibers, potentially playing a role in preventing extrusion.

PURPOSE

To analyze the meniscal extrusion prevention potential of the circumferential rim augmentation suture around the perimeniscal capsule in a rabbit root tear model and analyze the biomechanical function in a porcine cadaveric knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Rabbit medial meniscus root tear models were divided into 3 experimental groups: root tear, root tear and suture repair, and root tear and circumferential rim augmentation suture. As for the circumferential rim augmentation suture procedure, a suture was placed to circumscribe the outer rim of the medial meniscus and passed through bone tunnels located at the tibial insertion of each root. After 4 and 8 weeks, meniscal extrusion was analyzed by micro-computed tomography, gross morphology, and histologic analysis of the medial femoral cartilage. For biomechanical analysis, porcine knees were divided into groups similar to rabbit experiments. Tibiofemoral contact parameters were assessed using a pressure mapping sensor system after applying a load of 200 N on the knee joint.

RESULTS

The root tear and circumferential rim augmentation suture group showed less meniscal extrusion, less gap within the tear site, and less cartilage degeneration compared with other groups after 4 and 8 weeks of surgery in the rabbit root tear model. Biomechanical analysis showed the root tear and circumferential rim augmentation suture group had larger contact area and lower peak contact pressure compared with root tear and root tear and suture repair groups.

CONCLUSION

The circumferential rim augmentation suture reduced the degree of meniscal extrusion while restoring meniscal function, potentially preventing progression of arthritis in a rabbit root tear model and porcine knee biomechanical analysis.

CLINICAL RELEVANCE

The circumferential rim augmentation suture may be a novel augmentation option during root tear treatment.

Peripheral Stabilization Suture to Address Meniscal Extrusion in a Revision Meniscal Root Repair: Surgical Technique and Rehabilitation Protocol

Meniscal root tears are an increasingly recognized condition. These tears can cause the meniscus to become extruded outside the joint, which can diminish the biomechanical functionality of the meniscus. Anatomic repair of the meniscal root has previously been described, but this surgical procedure may not adequately address severe extrusion of the meniscal tissue. Additionally, when a primary anatomic repair fails, meniscal extrusion can increase, which can possibly accelerate joint degeneration if untreated. Therefore, the purpose of this Technical Note is to describe our surgical technique for revision medial meniscal root repair with a peripheral stabilization suture to address medial meniscal root tears with severe meniscal extrusion.

Medial Meniscus Root Repair in Patients With Open Physes

Meniscal root tears have become increasingly recognized in the past decade. Lateral meniscus root tears typically occur in active, younger patients who sustain acute anterior cruciate ligament tears. Conversely, medial meniscus root tears typically occur in isolation and affect middle-aged patients. However, recent reports have described the incidence of meniscal root tears occurring in pediatric populations who are skeletally immature. The purpose of this technical note is to describe the authors' surgical technique for medial meniscal root repair for patients with open physes.

Injury of the Meniscus Root

Meniscus root tears biomechanically disrupt normal joint loading and lead to joint overload with the possible development of spontaneous osteonecrosis of the knee and early-onset osteoarthritis. Proper identification and treatment of meniscal root tears has been proven to restore joint loading and improve patient outcomes.

Non anatomic reinsertion after amputation of the anterior horn of the lateral meniscus

Anatomical reinsertion is the optimal treatment for meniscal root injuries. However, in chronic settings, tissue fraying of the meniscal root may impede it. This study describes a salvage technical procedure performed in 3 cases of chronic anterior root avulsion of the lateral meniscus with profuse tissue degeneration in which remnant debridement resulted in amputation of the root. Reinsertion of the meniscus at the remaining healthy tissue was performed using an all-inside anchoring technique.

Type II Medial Meniscus Root Repair With Peripheral Release for Addressing Meniscal Extrusion

Medial meniscal root tears are often disabling injuries that can occur in isolation during low-velocity, deep knee flexion maneuvers in middle-aged patients. The most common meniscal root tear pattern is a radial tear near the root attachment (type II). Root tears are often associated with meniscal extrusion, identified on magnetic resonance imaging. Relocation of the meniscal root to its anatomic center is a reported current difficulty faced by surgeons during surgical repair. However, this can be achieved via sufficient peripheral release of the posteromedial capsular attachment of the medial meniscus. The purpose of this Technical Note is to describe the authors' current surgical technique for medial meniscus root repair with a peripheral release for addressing meniscal extrusion. Classifications: level I (knee); level II (meniscus).

Knotless Suture Anchor Repair of Anterolateral Meniscus Root After Iatrogenic Injury

In recent years there has been increased attention on preserving the menisci because they perform vital roles in maintaining knee joint homeostasis. The anterolateral (AL) meniscal root is particularly vulnerable during anterior cruciate ligament reconstruction. When the AL root is iatrogenically injured, it is imperative that it is repaired in a timely fashion to prevent early-onset osteoarthritis. In this article we outline our knotless suture anchor repair for AL root tears.

The role of meniscal repair for prevention of early onset of osteoarthritis

BACKGROUND

The meniscus plays an important role in the integrity of the knee joint. Therefore, meniscus tissue preserving techniques for the therapy of meniscus injuries seem to be reasonable. One of the important questions is whether meniscal repair can prevent the knee joint from early onset of osteoarthritis.

METHODS

According to the review of the current literature, the principles of a successful meniscal repair are explained and the functional outcome and its impact on the prevention of osteoarthritis are analyzed in this article.

RESULTS

Current data show a positive impact of a successful meniscus repair on the functional outcome in long-term. By this a protective effect on the development of osteoarthritis via the repair of meniscus lesions to restore the meniscus integrity can be confirmed. However, higher rates of re-operations in context to meniscus suturing have to be considered.

CONCLUSION

Due to the improved functional outcomes as well as preventive effect on the development of osteoarthritis within the knee joint in long-term, it is of importance to preserve as much meniscus tissue as possible in meniscus therapy. Patients previously have to be informed about the higher revision rate in context to meniscus suturing.

Novel technique for repairing posterior medial meniscus root tears using porcine knees and biomechanical study

Transtibial pullout suture (TPS) repair of posterior medial meniscus root (PMMR) tears was shown to achieve good clinical outcomes. The purpose of this study was to compare biomechanically, a novel technique designed to repair PMMR tears using tendon graft (TG) and conventional TPS repair. Twelve porcine tibiae (n = 6 each) TG group: flexor digitorum profundus tendon was passed through an incision in the root area, created 5 mm postero-medially along the edge of the attachment area. TPS group: a modified Mason-Allen suture was created using no. 2 FiberWire. The tendon grafts and sutures were threaded through the bone tunnel and then fixed to the anterolateral cortex of the tibia. The two groups underwent cyclic loading followed by a load-to-failure test. Displacements of the constructs after 100, 500, and 1000 loading cycles, and the maximum load, stiffness, and elongation at failure were recorded. The TG technique had significantly lower elongation and higher stiffness compared with the TPS. The maximum load of the TG group was significantly lower than that of the TPS group. Failure modes for all specimens were caused by the suture or graft cutting through the meniscus. Lesser elongation and higher stiffness of the constructs in TG technique over those in the standard TPS technique might be beneficial for postoperative biological healing between the meniscus and tibial plateau. However, a slower rehabilitation program might be necessary due to its relatively lower maximum failure load.