Meniscal root tears: a silent epidemic

A case report of simultaneous tears of the medial and lateral posterior meniscal roots with an intact ACL graft

INTRODUCTION AND IMPORTANCE

Meniscal root tears are defined as soft-tissue and/or osseous injuries that rip or avulse within one centimeter of the meniscal insertion to the tibial plateau. These injuries impact around 100,000 patients a year and make up 10 % to 21 % of all meniscal tears. Meniscal extrusion frequently happens when there are root rips, and the transmission of circumferential hoop loads is hampered.

CASE PRESENTATION

We present one case of a 28-year-old male who complained of pain and stiffness in his left knee since 2 years after undergoing ACL reconstruction using a hamstring autograft. His examination revealed joint line tenderness on both the medial and lateral sides of the left knee. Further investigations involving X-ray and MRI established the diagnosis of both medial and lateral meniscal root tears, which were surgically managed using the transtibial pullout technique.

DISCUSSION

The biomechanical implications of meniscal root tears, such as loss of hoop forces and increased tibiofemoral contact pressures, underscore the importance of timely diagnosis and management. The literature advocates surgical treatment for managing root tears, as leaving them without surgical intervention can lead to functional outcomes similar to those of total meniscectomy.

CONCLUSION

This case report presents both menisci posterior root tears with an intact ACL graft which is unique in that they commonly tear in conjuction with ACL. These kind of injuries necessitates prompt diagnosis and surgical intervention to protect the knee from early arthritic changes.

Seven tesla knee MRI T2*-mapping detects intrasubstance meniscus degeneration in patients with posterior root tears

Background

Medial meniscus root tears often lead to knee osteoarthritis. The extent of meniscal tissue changes beyond the localized root tear is unknown.

Purpose

To evaluate if 7 Tesla 3D T2*-mapping can detect intrasubstance meniscal degeneration in patients with arthroscopically verified medial meniscus posterior root tears (MMPRTs), and assess if tissue changes extend beyond the immediate site of the posterior root tear detected on surface examination by arthroscopy.

Methods

In this prospective study we acquired 7 T knee MRIs from patients with MMPRTs and asymptomatic controls. Using a linear mixed model, we compared T2* values between patients and controls, and across different meniscal regions. Patients underwent arthroscopic assessment before MMPRT repair. Changes in pain levels before and after repair were calculated using Knee Injury & Osteoarthritis Outcome Score (KOOS). Pain changes and meniscal extrusion were correlated with T2* using Pearson correlation (r).

Results

Twenty patients (mean age 53 ± 8; 16 females) demonstrated significantly higher T2* values across the medial meniscus (anterior horn, posterior body and posterior horn: all P < .001; anterior body: P = .007), and lateral meniscus anterior (P = .024) and posterior (P < .001) horns when compared to the corresponding regions in ten matched controls (mean age 53 ± 12; 8 females). Elevated T2* values were inversely correlated with the change in pain levels before and after repair. All patients had medial meniscal extrusion of ≥2 mm. Arthroscopy did not reveal surface abnormalities in 70% of patients (14 out of 20).

Conclusions

Elevated T2* values across both medial and lateral menisci indicate that degenerative changes in patients with MMPRTs extend beyond the immediate vicinity of the posterior root tear. This suggests more widespread meniscal degeneration, often undetected by surface examinations in arthroscopy.

Longitudinal changes in medial meniscus extrusion and clinical outcomes following pullout repair for medial meniscus posterior root tears: a 3-year evaluation

PURPOSE

We aimed to evaluate the longitudinal changes in medial meniscus extrusion (MME) and clinical scores at multiple time points up to 3 years after pullout repair for medial meniscus posterior root tears (MMPRTs).

METHODS

This retrospective case series study included 64 patients who underwent pullout repair for MMPRTs and four MRI evaluations (preoperatively and at 3 months, 1 year, and 3 years postoperatively). MME was measured during the same time points. Clinical scores were assessed four times: preoperatively and at 1, 2, and 3 years postoperatively. Additionally, a multivariate analysis was performed on the change in MME (ΔMME) from the preoperative measurement point to 3 years postoperatively.

RESULTS

The ΔMME per month from the preoperative measurement point to 3 months postoperatively, from 3 months to 1 year postoperatively, and from 1 to 3 years postoperatively were 0.30, 0.05, and 0.01 mm/month, respectively. All clinical scores significantly improved 3 years postoperatively (p < 0.001). In a multiple regression analysis for ΔMME from the preoperative measurement point to 3 years postoperatively, sex significantly affected the outcome (p = 0.039).

CONCLUSION

Following pullout repair for MMPRTs with well-aligned lower extremities, although MME progression could not be entirely prevented, the rate of progression decreased over time, and clinical scores improved. In particular, MME progressed markedly during the first 3 months postoperatively. Additionally, sex had a significant influence on MME progression, suggesting that males may be able to expand the indications of pullout repair for MMPRTs.

Double-Needle Technique for Temporary Stabilization of Unstable Meniscal Tear During All-Inside Meniscal Repair

Meniscus tears are common in patients with primary or revision anterior cruciate ligament injuries. Given their important mechanical role in the joint, efforts are being made to repair as much of the meniscus tear as possible. However, all-inside repair might be challenging in case of an unstable tear due to the dislocation of the meniscal flap after deploying the first anchor. Therefore, we describe the details of our technique that allows the surgeon to stabilize the meniscal tear before all-inside repair, ensuring the reduction of the tear throughout the entire procedure.

Meniscus root tears: state of the art

BACKGROUND

Meniscus root tears represent significant pathology that, historically, has been underdiagnosed and undertreated. However, the recognition of their clinical and functional significance has recently surged, mainly due to their frequent association with anterior cruciate ligament injuries.

AIM

This comprehensive review discusses various aspects of meniscal root tears, including their epidemiology, biomechanics, etiology, clinical and radiological findings, classification, management and surgical techniques.

Meniscal Radial Tears: A Classification System Based on Tear Morphology

Appropriate management of radial meniscal tears is complex, with continued efforts focused on optimizing diagnostic methods for identification to help dictate treatment, especially as surgical indications for repair have expanded, coupled with improvements in surgical techniques and instrumentation. Currently, no standardized classification system for radial meniscal tears exists, limiting the ability to accurately characterize injury patterns and guide surgical decision-making.

A Systematic Review of Adverse Events and Complications After Isolated Posterior Medial Meniscus Root Repairs

BACKGROUND

Medial meniscus posterior root (MMPR) tears are recognized as a substantial cause of disability and morbidity. However, meniscus root repair, regardless of technique, is not without potential complications.

PURPOSE

To evaluate the reported incidence of complications and adverse events after isolated MMPR repair.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using Embase, PubMed, and Scopus databases with the following search terms combined with Boolean operators: "meniscus,""root," and "repair." Inclusion criteria consisted of level 1 to 4 human clinical studies in English or English-language translation reporting complications and adverse events after isolated posterior medial meniscus root repairs. The overall incidence of specific complications was estimated from the pooled sample of the included studies.

RESULTS

Eleven studies with a total pooled sample of 442 patients were identified. The mean patient age was 58.1 years, while the mean final follow-up time was 37.2 months (range, 12-84.8 months). The overall incidence of complications was 9.7% (n = 43/442), with the most commonly reported complication being progressive degenerative changes within the knee (10.4%; n = 25/240; n = 5 studies). A total of 1.25% (n = 3/240) of patients who experienced degenerative changes required conversion to total knee arthroplasty. Repair failures were reported in 3.1% (n = 10/327; n = 8 studies) of patients.

CONCLUSION

Repairing MMPR tears is critical in preventing accelerated progression of knee osteoarthritis in patients without significant knee osteoarthritis preoperatively. While this repair is still recommended and necessary in appropriate patients, this review found that the incidence of complications after isolated posterior medial meniscus root repair was 9.7%, primarily involving the presence of progressive degeneration, while repair failure was reported in 3% of patients.

Root Repair Has Superior Radiological and Clinical Outcomes Than Partial Meniscectomy and Nonoperative Treatment in the Management of Meniscus Root Tears: A Systematic Review

PURPOSE

To compile and analyze structural and clinical outcomes after meniscus root tear treatment as currently described in the literature.

METHODS

A review was conducted to identify studies published since 2011 on efficacy of repair, meniscectomy, and nonoperative management in the treatment of meniscus root tears. Patient cohorts were grouped into treatment categories, with medial and lateral root tears analyzed separately; data were collected on patient demographics, structural outcomes including joint space width, degree of medial meniscal extrusion, progression to total knee arthroplasty, and patient-reported outcome measures. Risk of bias was assessed using the MINORS (methodological index for non-randomized studies) criteria. Heterogeneity was measured using the I-statistic, and outcomes were summarized using forest plots without pooled means.

RESULTS

The 56 included studies comprised a total of 3,191 patients. Mean age among the included studies ranged from 24.6 to 65.6 years, whereas mean follow-up ranged from 12 to 125.9 months. Heterogeneity analysis identified significant differences between studies. Change in joint space width ranged from -2.4 to -0.6 mm (i.e., decreased space) after meniscectomy (n = 186) and -0.9 to -0.1 mm after root repair (n = 209); change in medial meniscal extrusion ranged from -0.6 to 6.5 mm after root repair (n = 521) and 0.2 to 4.2 mm after meniscectomy (n = 66); and event rate for total knee arthroplasty ranged from 0.00 to 0.22 after root repair (n = 205), 0.35 to 0.60 after meniscectomy (n = 53), and 0.27 to 0.35 after nonoperative treatment (n = 93). Root repair produced the greatest numerical increase in International Knee Documentation Committee and Lysholm scores of the 3 treatment arms. In addition, root repair improvements in Knee Injury and Osteoarthritis Outcome Score Pain (range: 22-32), Sports and Recreational Activities (range: 23-36), Quality of Life (range: 22-42), and Symptoms subscales (range: 10-19), in studies with low risk of bias.

CONCLUSIONS

The literature reporting on the treatment of meniscus root tears is heterogenous and largely limited to Level III and IV studies. Current evidence suggests root repair may be the most effective treatment strategy in lessening joint space narrowing of the knee and producing improvements in patient-reported outcomes.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

Increased Posterior Tibial Slope Is Associated With Increased Risk of Meniscal Root Tears: A Systematic Review

BACKGROUND

While increased posterior tibial slope (PTS) is an established risk factor for anterior cruciate ligament tears, the association between tibial slope and meniscal posterior root tears is not well-defined.

PURPOSE

To summarize the available literature evaluating the association between PTS and meniscus root injuries compared with patients without root tears.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A literature search was performed using the Scopus, PubMed, and Embase databases. Human clinical studies evaluating the associations between the medial tibial slope (MTS), lateral tibial slope (LTS), lateral-to-medial (L-to-M) slope asymmetry, and the risk of meniscus root tears were included. Patients with medial meniscus posterior root tears (MMPRTs) and lateral meniscus posterior root tears (LMPRTs) were compared with a control group without root injury. Study quality was assessed using the methodological index for non-randomized studies criteria.

RESULTS

Ten studies with 1313 patients were included (884 patients with root tears; 429 controls). The LMPRT subgroup (n = 284) had a significantly greater LTS (mean ± SD, 7.3°± 1.5° vs 5.7°± 3.91°; P < .001), MTS (5.26°± 1.2° vs 4.8°± 1.25°; P < .001), and increased L-to-M asymmetry (2.3°± 1.3° vs 0.65°± 0.5°; P < .001) compared with controls. The MMPRT group (n = 600) had significantly increased MTS relative to controls (8.1°± 2.5° vs 4.3°± 0.7°; P < .001). Furthermore, there was a higher incidence of noncontact injuries (79.3%) and concomitant ramp lesions (56%) reported in patients with LMPRT.

CONCLUSION

Increased MTS, LTS, and L-to-M slope asymmetry are associated with an increased risk of LMPRTs, while increased MTS is associated with MMPRTs. Surgeons should consider how proximal tibial anatomy increases the risk of meniscus root injury.

Superior outcomes of pullout repairs for medial meniscus posterior root tears in partial tear compared to complete radial tear

PURPOSE

To reveal the outcomes of partial medial meniscus posterior root tears following transtibial pullout repair compared with the outcomes of complete radial meniscus posterior root tears.

MATERIALS AND METHODS

We retrospectively evaluated 15 consecutive patients (male/female, 5/10; average age, 64.4 years) who underwent transtibial pullout repair for partial medial meniscus posterior root tears and compared their results with those of 86 consecutive patients who underwent the same surgery for complete medial meniscus posterior root tears. All patients underwent second-look arthroscopy on average 1 year postoperatively, and a semi-quantitative meniscal healing score (anteroposterior width, stability, and synovial coverage, total 10 points) was evaluated. Medial meniscus extrusion was evaluated preoperatively and at second-look arthroscopy.

RESULTS

Postoperative clinical scores were not significantly different in the short term. However, second-look arthroscopy revealed a significant difference in repaired meniscal stability (partial tear; 3.3 points, complete tear; 2.3 points, p < 0.001) and total meniscal healing scores (partial tear; 8.3 points, complete tear; 7.1 points, p < 0.001). Medial meniscus extrusion progression was significantly different (partial tear; 0.4 mm, complete tear; 1.0 mm, p < 0.001).

CONCLUSION

Partial medial meniscus posterior root tears showed better meniscal healing and less medial meniscus extrusion progression following pullout repair than complete medial meniscus posterior root tears.

Identical clinical outcomes between neutral and classic targeted alignments after high tibial osteotomy in medial meniscus posterior root tear: a prospective randomized study

PURPOSE

This study aimed to compare the clinical and radiographic outcomes and arthroscopic findings after high tibial osteotomy (HTO) between neutral and classic targeted coronal alignments in patients with medial meniscus posterior root tears (MMPRTs).

METHODS

Ninety-eight patients with MMPRT were prospectively enrolled in the final cohort and randomized into two groups. Fifty-two patients with the targeted alignment through the Fujisawa point (60-62.5% of the entire tibial plateau width measured from the medial side) during HTO were included in group A, whereas 46 patients with the targeted alignment through the point at 50-55% of the tibial plateau width were included in group B. The clinical and radiographic outcomes and second-look arthroscopic findings were statistically compared for comprehensive assessments.

RESULTS

After a mean follow-up of 37.1 months, we found no significant differences between the two groups regarding the final Lysholm (p = 0.205) and Hospital for Special Surgery scores (p = 0.084). However, we only observed significant differences between the two groups in terms of the final hip-knee-ankle angle, weight-bearing line ratio, and medial proximal tibial angle (p < 0.001). Second-look arthroscopy did not reveal a significant difference in meniscal healing rate (p = 0.786).

CONCLUSIONS

Performing HTO with the aim to achieve neutral alignment leads to similar clinical outcomes in patients with MMPRT compared to classic alignment. Although subsequent research is required, the current study provides clinical evidence for the safety and efficacy of the new targeted alignment during HTO, which may avoid long-term complications associated with overcorrection when using the traditional technique.

Outcomes After Meniscal Root Repair in Patients With and Without Advanced Patellofemoral Chondromalacia: Comparison at 2-Year Follow-up

Background

Meniscal root repair can improve patient outcomes significantly; however, several contraindications exist, including arthritic change to the medial or lateral tibiofemoral compartments.

Purpose/Hypothesis

The purpose of this study was to evaluate the outcomes of meniscal root repair in patients with advanced patellofemoral chondromalacia (PFC). It was hypothesized that the presence of advanced PFC would not significantly affect the postoperative outcomes.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective review was conducted of patients who underwent meniscal root repair with at least 2 years of follow-up data. Patients with chondromalacia as determined by arthroscopic visualization (defined as Outerbridge grade 3 or 4) were placed in the PFC group; patients with Outerbridge grade 0 to 2 chondromalacia were placed in the non-PFC group. Outcomes were measured by the Lysholm knee scoring scale and the International Knee Documentation Committee (IKDC) Subjective Knee Form. Clinical outcomes including complications were also recorded. Quantitative data between the groups were analyzed using the 2-tailed independent-samples t test.

Results

Overall, this study included 81 patients (35 in the PFC group, 46 in the non-PFC group). The mean follow-up times were 25.1 months in the PFC group and 24.8 months in the non-PFC group. In both groups, Lysholm and IKDC scores improved significantly with 24-month Lysholm scores averaging 85.86 in the PFC group and 86.61 in the non-PFC group (P = .62) and 24-month IKDC scores averaging 77.66 for the PFC group and 79.59 for the non-PFC group (P = .45). The cohorts demonstrated similar rates of retear, arthrofibrosis, infection, and progression to total knee arthroplasty.

Conclusion

The presence of advanced PFC was not associated with inferior outcomes in patients who underwent posterior meniscal root repair, and rates of recurrent tears, postoperative infection, arthrofibrosis, and conversion to total knee arthroplasty were similar between the study groups. These findings suggest that PFC may not significantly alter the results of meniscal root repair and should not be considered an absolute contraindication for this procedure.

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.

Shear stress in the medial meniscus posterior root during daily activities

BACKGROUND

Medial meniscus posterior root (MMPR) tears have been reported to occur in middle-aged patients with minor trauma. However, the injury mechanism of MMPR tears remains unclear. The purpose of this study was to evaluate the shear stress in the MMPR during daily activities using a finite-element analysis.

METHODS

Subject-specific finite-element models of the knee joint of a healthy middle-aged subject were developed from computed tomographic and magnetic resonance images. A three-dimensional motion capture system "VICON" was used to capture four daily activities: walking, jogging, descending stairs, and landing. The knee joint reaction force was estimated using the AnyBody modeling system. Based on these procedures, the shear stress in the MMPR was calculated during each motion. The shear stress in the lateral meniscus posterior root (LMPR) was also measured to compare the stress between the MMPR and LMPR.

RESULTS

The shear stress in the MMPR increased as the knee flexion angle increased during each motion. Descending stairs caused more than two-fold greater stress in the MMPR than walking and a similar or greater amount of stress than jogging. The LMPR tended to receive more shear stress than the MMPR throughout each motion.

CONCLUSIONS

The present study showed that descending stairs confers almost the same amount of shear stress to the MMPR as jogging. The results of the present study may suggest that descending motion of the knee is an important cause of MMPR tear, and the initiation of descending stairs should be delayed after MMPR repair.

Posteromedial capsular anatomy of the tibia for consideration of the medial meniscal support structure using a multidimensional analysis

Medial meniscal extrusion (MME) is a structural abnormality that leads to early knee osteoarthritis; however, its formation remains debated. For anatomical consideration of the mechanism underlying MME formation, we examined the capsular attachment on the posteromedial tibia and its layered association with the semimembranosus. Fourteen knees of eight body donors were analyzed in this study; six knees were grouped for macroscopic analysis, whereas four knees each were grouped for histological and phosphotungstic acid-enhanced micro-computed tomography analyses. The capsular attachment varied in width according to location and was not distant from the articular cartilage and posterior root. A portion of the posteromedial joint capsule formed the semimembranosus tendinous sheath. The dense fibrous membrane superficial to the semimembranosus, which was continuous from its tendinous sheath, existed as one of the layers of the joint capsule. The aforementioned findings were confirmed in all specimens. Based on the capsular attachment and its layered association with the semimembranosus, the conventional posteromedial knee ligaments may be only a part of the joint capsule divided into two layers by the semimembranosus. If the coordinated action of the joint capsule and semimembranosus partially contributes to the medial meniscus stability, such a structural problem may affect MME formation.

A Biomechanical Comparison of All-Inside Versus Transtibial Meniscus Root Repair Techniques

BACKGROUND

Meniscus root tears are associated with chondral injury, early degenerative change, and a high conversion rate to total knee arthroplasty. It is well-established that meniscus root tears lead to decreased femorotibial contact area, increased peak contact pressures, and increased stress on the articular cartilage.

PURPOSE

To evaluate the biomechanical characteristics of the all-inside meniscus root repair procedure and compare it with the previously described transtibial technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine paired cadaveric knees were prepared by removing skin, subcutaneous tissues, quadriceps muscles, patella, and patellar tendon, while leaving the capsule in place. Pressure-mapping sensors were inserted, and specimens underwent compressive loading to obtain peak pressures, mean pressures, and femorotibial contact area in the medial and lateral compartments. Tests were performed as static compression tests with the knee locked at 0° of flexion. Compression testing was performed in 3 states: meniscus intact, meniscus root cut, and after meniscus root repair with an all-inside repair technique. Additionally, testing was completed on 9 pairs of cadaveric knees to compare stiffness and maximal load to failure between the all-inside and transtibial meniscus root repair techniques.

RESULTS

In the medial compartment, there were significant increases in median peak pressures and median mean pressures in the root cut state as compared with the intact state (+636 kPA [95% CI, 246 to 1026] and +190 kPA [95% CI, 49 to 330], respectively). All-inside meniscus root repair restored median peak pressures and median mean pressures to approach those of the intact meniscus (+311 kPA [95% CI, -79 to 701] and +137 kPA [95% CI, -3 to 277]). In the lateral compartment, there were also significant increases in median peak pressures and median mean pressures in the root cut state as compared with the intact state (+718 kPA [95% CI, 246 to 1191] and +203 kPA [95% CI, 51 to 355]). All-inside meniscus root repair restored median peak pressures and median mean pressures such that they were not significantly different from the intact state (+322 kPA [95% CI, -150 to 795] and +18 kPA [95% CI, -134 to 171]). There was no difference between repair techniques regarding load to failure (P = .896). Transtibial meniscus root repair had significantly more stiffness (mean ± SD, 24.8 ± 9.3 N/mm) as compared with the all-inside meniscus root repair technique (13.6 ± 3.8 N/mm, P = .015).

CONCLUSION

All-inside meniscus root repair reduced median peak and mean pressures to those of the native intact meniscus with the knee in extension in the cadaveric model. When compared with a transtibial meniscus root repair technique, all-inside repair demonstrated decreased stiffness and a similar load to failure.

CLINICAL RELEVANCE

All-inside meniscus root repair restored mean and peak femorotibial pressures to those of the intact meniscus. Additionally, it offers a technically easier technique for management of meniscus root tears.

Top Ten Pearls for a Successful Transtibial Pull-Out Repair of Medial Meniscal Posterior Root Tears With a Concomitant Centralization Stitch

Although historically overlooked, medial meniscus posterior root (MMPR) tears are now increasingly recognized as a substantial cause of biomechanical impairment and morbidity. MMPR tears, when left untreated, are strongly correlated to meniscal extrusion and ultimately lead to altered kinematics and loading functionally equivalent to a total meniscectomy. To prevent progressive joint degeneration and alleviate pain while re-establishing native joint kinematics, MMPR repair is generally recommended in appropriately selected patients. In this Technical Note, the authors describe a detailed checklist with 10 crucial points of emphasis when performing the gold-standard transtibial pull-out repair of the MMPR, with an additional centralization stitch, providing technical pearls backed up by previous literature and ample experience treating this condition.

Meniscal Extrusion: Diagnosis, Etiology, and Treatment Options

PURPOSE OF REVIEW

The concept of meniscal extrusion has recently been recognized as a hallmark of meniscus dysfunction. This review examines contemporary literature regarding the pathophysiology, classification, diagnosis, treatment, and future directions for investigation regarding meniscus extrusion.

RECENT FINDINGS

Meniscus extrusion, defined as >3 mm of radial displacement of the meniscus, leads to altered knee biomechanics and accelerated knee joint degeneration. Meniscus extrusion has been associated with degenerative joint disease, posterior root and radial meniscal tears, and acute trauma. Meniscus centralization and meniscotibial ligament repair have been proposed as techniques to address meniscal extrusion with promising biomechanical, animal model, and early clinical reports. Further studies on the epidemiology of meniscus extrusion and associated long-term nonoperative outcomes will help to elucidate its role in meniscus dysfunction and resultant arthritic development. Understanding and appreciation for the anatomic attachments of the meniscus will help to inform future repair techniques. Long-term reporting on the clinical outcomes of meniscus centralization techniques will yield insights into the clinical significance of meniscus extrusion correction.

Patients with meniscus posterolateral root tears repair during ACL reconstruction achieve comparable post-operative outcome than patients with isolated ACL reconstruction

PURPOSE

Lateral posterior meniscal root tear (LPMRT) repair, at the time of anterior cruciate ligament (ACL) reconstruction are increasingly being performed. The aim of this study was to compare the clinical and functional outcomes, as well as the complication rates at a minimum of 2 years follow-up, between an isolated ACL reconstruction group with intact menisci and a combined ACL reconstruction and LPMRT repair group.

METHODS

All patients who underwent combined ACL reconstruction and LPMRT repair between 2016 and 2020 were included in the study. They were matched with an isolated ACL reconstruction group with intact menisci based on age, gender and the pre-injury IKDC score. The KOOS, ACLRSI Tegner-Lysholm score and the TELOS-test were collected pre- and postoperatively; complications (re-rupture, recurrence or persistence of a high grade pivot shift, new meniscal injury) were recorded. All LPMRTs were repaired using transtibial pull-out technique.

RESULTS

After matching, 100 patients were included in this study (mean age 29.6 ± 1.0 years and mean follow-up 42.9 ± 7.3 months): 50 patients in the isolated ACL reconstruction group with intact menisci (group A) and 50 in the combined ACL reconstruction and LPMRT repair group (group B). Preoperatively, patients in group B had significant lower KOOS scores (Global 55.9 ± 2.9 vs. 64.6 ± 2.3, p = 0.02), but similar ACLRSI, TEGNER and TELOS scores. At the last follow-up, all functional scores had improved, and no significant difference between the two groups on any score was observed. There was also no difference in terms of complications rates.

CONCLUSION

At a minimum of 2 years follow-up (mean follow-up 42.9 months), LPMRT repair during ACL reconstruction has no significant difference in terms of post-operative functional outcomes compared to the isolated ACL reconstruction group.

LEVEL OF EVIDENCE

Level III.

Editorial Commentary: High Tibial Osteotomy May Not Be Required With Medial Meniscus Root Repair

Meniscal root tears are defined as tears within 10 mm of their attachment and are more commonly observed in middle-aged patients. They have been named the silent epidemic and are equivalent to a total meniscectomy. Basic science studies have shown that posterior meniscus root repairs restore both contact area and pressure to its native state. The role of an additional high tibial osteotomy is not clear yet. High tibial osteotomies are commonly used to correct varus malalignment, a condition that is often observed with these tears. However, an additional osteotomy does not seem to offer any additional clinical benefits with regards to clinical and radiologic outcomes. It also has no effect with regards to contact pressure and contact area and is not related to the degree of deformity correction.

Benefits of Meniscal Repair in Selected Patients Aged 60 Years and Older

Background

Little is known about the benefits and outcomes of meniscal repair in patients older than 60 years.

Purpose

To (1) report the clinical and radiographic outcomes of meniscal repair in patients aged ≥60 years and compare them with matched patients who underwent meniscectomy and (2) identify procedural failures.

Study Design

Cohort study; Level of evidence, 2.

Methods

We included 32 knees in 32 patients aged ≥60 years (20 female, 12 male; mean age, 64.5 ± 4.6 years) who underwent meniscal repair surgery at a single medical institution between 2010 and 2020. Patients were matched according to age, sex, body mass index, and meniscal tear type with a comparison cohort who underwent meniscectomy (n = 49 patients [49 knees]; 32 female, 17 male). For all patients, demographic information, clinical history, physical examination findings, treatment details, and radiographic images were reviewed and analyzed. At final follow-up (mean, 42.2 months; range, 13-128 months), patients completed the 2000 International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm score. Clinical failure was defined as revision surgery and/or progression to total knee arthroplasty (TKA). A matched-pairs t test was used to analyze differences between the 2 treatment groups, and Kaplan-Meier analysis was used to determine the rates of knee osteoarthritis and progression to TKA.

Results

The majority of patients had a medial meniscal tear (72.8%), whereas the lateral meniscus was torn in 27.2% of cases. Most tears were located in the meniscal root (56.8%), followed by the posterior horn (34.6%) and midbody (8.6%). At final follow-up, all outcome scores were higher in the repair group compared with the meniscectomy group (IKDC, 78.9 ± 13.4 vs 56.0 ± 15.4; KOOS, 86.6 ± 11.9 vs 61.7 ± 16.2; Lysholm, 88.3 ± 13.3 vs 68.7 ± 15.2, respectively; P < .001 for all). Clinical failure was observed in 22% of patients in the repair group.

Conclusion

All clinical outcome scores were higher in the meniscal repair group compared with the matched meniscectomy group at final follow-up. The clinical failure rate of the repair group was 22%. These findings support meniscal repair in selected patients aged ≥60 years.

Review of Meniscus Anatomy and Biomechanics

PURPOSE OF REVIEW

Anatomic repair of meniscal pathology is critical for restoring native joint biomechanics and kinematics for patients who suffer from meniscal tears. The purpose of this review was to summarize the pertinent anatomy, biomechanics, and kinematics of the meniscus to guide surgeons during meniscal repair procedures.

RECENT FINDINGS

Over the past decade, there has been a growing trend to save the meniscus whenever possible. The goal of repair should be to recreate native anatomy as close as possible to recapitulate normal mechanics. Studies describing the quantitative and qualitative relationship of the meniscus roots, ligaments, and attachments are key in guiding any meniscus repair. This review summarizes these relationships, with particular emphasis on meniscal roots and other key attachments to the meniscus. The composition, embryology, vascularization, biomechanics, in vivo kinetics, and in vivo kinematics of the meniscus are also discussed in this review. Meniscal tears can cause profound functional, biomechanical, and kinematic derangements within the knee joint leading to accelerated degeneration of the articular cartilage. A strong understanding of the quantitative and qualitative relationships of the meniscus and its attachments with key arthroscopic landmarks will allow a surgeon to anatomically repair meniscal pathology in order to restore native joint biomechanics.

Meniscal Root Tears: An Update Focused on Preoperative and Postoperative MRI Findings

Meniscal root tears represent radial tears or avulsions of the meniscal cartilage at the tibial attachment site that profoundly affect meniscal biomechanics and kinematics. Meniscal root tears have the functional effect of a total meniscectomy and can lead to rapid degenerative change with development of early knee osteoarthritis (OA). A growing range of arthroscopic surgical techniques have been developed to repair meniscal root tears with the aim of restoring joint kinematics and contact pressures and delaying the development of OA. With increased understanding of the anatomy and biomechanics of the meniscal root, meniscal root injury repair has become the treatment of choice in knees with nonadvanced OA. This article reviews the anatomy and biomechanics of the meniscal roots, clinical and imaging diagnostic criteria of meniscal root tears, correlation between arthroscopy and MRI in the diagnosis and classification of meniscal root tears, and expected and abnormal MRI findings after meniscal root repair. Familiarity with MRI signs and classifications of meniscal root tears, as well as with root repair surgical techniques, can aid radiologists in correctly reporting preoperative and postoperative MRI findings.

Developing an experimental model of early knee osteoarthritis after medial meniscus posterior root release: an in vivo study

Purpose

To develop a predictable and reproducible model of knee osteoarthritis after medial meniscus posterior root release.

Methods

Posteromedial meniscal root tears were created in 12 White New Zealand rabbit knees. The 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 analyses to detect signs of early degeneration. Clinical evaluation of the weight-bearing status on the affected knee was conducted at 0-, 4-, 8-, and 16-weeks postoperatively.

Results

Early and severe osteoarthritic changes were the hallmark and the main findings after 16-weeks post-surgery. Macroscopically, extensive osteoarthritic changes were observed across the femoral condyle and tibial plateau. Microscopic finding included ulcerations, fissures, fibrillations, pitting, and loss of the superficial layer. Cellularity was diminished, the normal pattern of distribution in columns was lost, and subchondral bone exposure was also evident.

Conclusions

This study describes a novel model of knee osteoarthritis that may guide the development of tailored interventions to delay or prevent knee osteoarthritis. This knowledge could shift the current treatment paradigm toward more conservative and knee salvageable treatment options and increase surgeons’ awareness of this injury pattern. Such considerations may have a positive impact on clinical decision-making and subsequent patient-reported clinical outcomes.

Design

Controlled laboratory study.

Level of evidence

II.

Meniscal Tear Management Associated with ACL Reconstruction

Meniscal lesions often occur in association with anterior cruciate ligament (ACL) tears at the moment of the injury or, secondarily, as a consequence of knee instability. Both ACL and meniscus lesions are associated with a higher risk of osteoarthritis. Adequate treatment of these lesions reduces the rate of degenerative changes in the affected knee. Meniscal tears should be addressed concomitantly with ACL reconstruction and the treatment must be oriented towards preserving the meniscal tissue anytime this is possible. Several options for approaching a meniscus tear are available. The meniscal suture should always be considered, and, if possible, meniscectomy should be the last choice. “Masterly neglect” is a valuable option in selected cases.

Meniscus Root Tears: A Clinical Review

ABSTRACT

Meniscus root tears are important to recognize early given their potentially devastating consequences on joint health. This injury results in the lost ability of the meniscus to transfer axial loads into hoop stress; therefore, it is functionally equivalent to a complete meniscectomy. This causes rapid progression of osteoarthritis and increased need to total knee arthroplasty in a previously healthy joint. Despite these consequences, root tears have only been discussed in the orthopedic literature in the last 10 to 15 years and have not been routinely integrated into nonoperative sports medicine education. It is important for all nonoperative sports medicine providers to properly diagnose and triage this injury early in its course to maximize joint preservation efforts. The goal of this manuscript is to review the anatomy, presentation, natural history, imaging, and treatment options for meniscal root tears.

Optimal Tibial Tunnel Placement for Medial and Lateral Meniscus Root Repair on the Anteromedial Tibia in the Setting of Anterior and Posterior Cruciate Ligament Reconstruction of the Knee

BACKGROUND

Although the risk of tibial tunnel convergence in the setting of multiligamentous reconstruction has been reported in the literature, the risk of tunnel convergence in the setting of posterior cruciate ligament (PCL), anterior cruciate ligament (ACL) reconstruction and medial and lateral meniscus root repair has not been defined.

PURPOSE

To examine the risk of tunnel convergence and to determine optimal tunnel placement for ACL and PCL reconstruction performed in conjunction with posterior medial and lateral meniscus root repairs on the anteromedial proximal tibia.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Three-dimensional (3D) tibial models were created using computed tomography scans of 20 cadaveric specimens. After determining optimal tunnel entry and exit points for ACL and PCL reconstructions, and medial and lateral meniscus root reattachment to the anatomic footprints, we used image processing software to create root tunnels over the anteromedial tibia on the tibial models. ACL and PCL tunnels were kept constant. The meniscus root repair tunnels were then reoriented to match the angle of the ACL tunnel, making both tunnels parallel in the sagittal plane. Tunnel convergence risk was analyzed by identifying the shortest 3D distance between tunnel axes and subtracting the radius of each tunnel from this distance for single- and double-tunnel repair techniques in both case scenarios.

RESULTS

All specimens demonstrated convergence between the ACL and lateral meniscus root tunnels when the root tunnel's entry was created proximal to the ACL tunnel's entry for single- and double-tunnel techniques, but no convergence was seen between these tunnels using the parallel orientation in the sagittal plane. There were no cases of convergence between the ACL and medial meniscus root tunnels in any of the configurations. The greatest distance between the ACL and medial meniscus root tunnels was achieved using the single-tunnel technique in parallel orientation (12.1 ± 2.8 mm). There were no cases of convergence between the PCL and medial meniscus root tunnels in the original orientation; however, 2 of 20 specimens demonstrated convergence using the parallel orientation with the double-tunnel technique, and there were no cases of convergence using the single-tunnel technique. The PCL and lateral meniscus root tunnels did not demonstrate convergence in any configuration.

CONCLUSION

There was a high risk of convergence between ACL and posterior meniscus root tunnels when all the tunnels were created on the anteromedial tibia. Reorienting meniscus root tunnels parallel to ACL tunnels may help reduce this risk. There is increased risk of tunnel convergence with root repairs in cases of bicruciate reconstructions, and therefore a double-tunnel root repair technique should be used with caution.

CLINICAL RELEVANCE

To avoid tibial tunnel convergence when performing ACL and PCL reconstruction with medial and lateral meniscus root repair, surgeons should reorient the meniscus root repair tunnels to be parallel on the sagittal plane to the ACL tunnel to decrease the risk of convergence. In cases of bicruciate ligament reconstruction, use of the double-tunnel technique requires caution to avoid convergence risk with the PCL tunnel.

Meniscal Root Repair Alone or Combined with Different Procedures After at Least 6 Months of Follow-Up: A Series of Cases

Purpose

To analyze clinical and functional outcomes of patients submitted to posterior meniscal root repair of the medial or lateral meniscus in different settings, with at least 6 months of follow-up.

Patients and Methods

Retrospective multicentric study assessing epidemiological characteristics and clinical-functional results of 22 patients who underwent meniscal root reinsertion (MRR) by transtibial technique. This study addressed different settings: isolated medial root repair, medial root repair associated with high tibial osteotomy (HTO) and lateral root repair associated with anterior cruciate ligament (ACL) reconstruction.

Results

Twelve patients had an isolated tear of the posterior root of the medial meniscus and underwent MRR alone. Six patients had a varus axis >5°, undergoing MRR in addition to HTO in the same surgical procedure. Four patients underwent repair of the posterior root of the lateral meniscus associated with simultaneous reconstruction of the ACL. The main results of the study were observed in the improvement of the IKDC score from 27.7% preoperatively to 69.8% in the postoperative period (p < 0.0001) and the Lysholm score of 44.4 points preoperatively to 88.4 points in the postoperative period (p < 0.0001). Significant clinical and subjective improvements were also reported.

Conclusion

Medial meniscal root repair, associated or not with valgus tibial osteotomy (when indicated) and lateral meniscal root repair associated with ACL reconstruction, improved clinical, functional, and subjective results of the patients presented in this case series in the short term.

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The Natural History of Medial Meniscal Root Tears: A Biomechanical and Clinical Case Perspective

Posterior medial meniscus root tears (PMMRTs) make up a relatively notable proportion of all meniscus pathology and have been definitively linked to the progression of osteoarthritis (OA). While known risk factors for development of OA in the knee include abnormal tibial coronal alignment, obesity and female gender, PMMRTs have emerged in recent years as another significant driver of degenerative disease. These injuries lead to an increase in average contact pressure in the medial compartment, along with increases in peak contact pressure and a decrease in contact area relative to the intact state. Loss of the root attachment impairs the function of the entire meniscus and leads to meniscal extrusion, thus impairing the force-dissipating role of the meniscus. Anatomic meniscus root repairs with a transtibial pullout technique have been shown biomechanically to restore mean and peak contact pressures in the medial compartment. However, nonanatomic root repairs have been reported to be ineffective at restoring joint pressures back to normal. Meniscal extrusion is often a consequence of nonanatomic repair and is correlated with progression of OA. In this study, the authors will describe the biomechanical basis of the natural history of medial meniscal root tears and will support the biomechanical studies with a case series including patients that either underwent non-operative treatment (5 patients) or non-anatomic repair of their medial meniscal root tears (6 patients). Using measurements derived from axial MRI, the authors will detail the distance from native root attachment center of the non-anatomic tunnels and discuss the ongoing symptoms of those patients. Imaging and OA progression among patients who were treated nonoperatively before presentation to the authors will be discussed as well. The case series thus presented will illustrate the natural history of meniscal root tears, the consequences of non-anatomic repair, and the findings of symptomatic meniscal extrusion associated with a non-anatomic repair position of the meniscus.

A comparison of the transtibial pullout technique and all-inside meniscal repair in medial meniscus posterior root tear: Prognostic factors and midterm clinical outcomes

Introduction

There is a paucity of comparative clinical data between arthroscopic all-inside end-to-end meniscal root suture and transtibial pullout technique in medial meniscus posterior root tears (MMPRT). Therefore, this study aimed to compare treatment failure, mid-term clinical and radiological outcomes of all-inside meniscus root repair versus the transtibial pullout technique and to analyze prognostic factors of postoperative clinical and radiological outcomes.

Material and methods

Forty-four patients were included in two therapeutic group: arthroscopic all-inside meniscal suture (MS: 13 knees) and transtibial pullout technique (TP: 31 knees).Primary clinical outcomes at a minimum of 27.2 months postoperatively included Knee injury and Osteoarthritis Outcome Score (KOOS) and Lysholm Knee Questionnare (LKQ). Radiographic assessment of the knee was performed to determine osteoarthritis severity using the Kellgren-Lawrence (KL) grading system.In addition, pre and postoperative MRI scans and intraoperative arthroscopic findings were recorded and the correlations between these findings, as outcome predictors and postoperative patients reported subjective outcome were assessed.

Results

No significant differences in postoperative KOOS and LKQ scores were found between the MS and TP group (p = 0.38 and 0.17, respectively).During follow-up one patients (7.7%) in the MS group and two (6.5%) in the TP group underwent total knee arthroplasty. The difference did not reach the statistical significance (p = 0.88).No differences were observed in postoperative MRI findings such as meniscal extrusion, osteochondral defect, chondromalacia patella, and bone morrow edema (p = 0.25, 0.97, 0.97, and 0.88, respectively).A univariate model revealed that the presence of postoperative meniscal extrusion; osteochondral defect; chondromalacia patella; increased BMI; age (>40 years) and longer time lapse between clinical onset to surgery (>6 months) were predictors of poor clinical outcome. The presence of meniscal extrusion, osteochondral defect and chondropatia patella portended worst postoperative outcomes in a multiple linear regression model.

Conclusions

It can be concluded that both techniques can reach good results when performed properly and if the injury pattern allows meniscal suture may be considered a treatment option for the management of MMPRT in well-selected patients.Patients with increased BMI, preoperative meniscal extrusion, chondromalacia patella, and osteochondral defect were at higher risk of poor clinical outcomes.

Stay Ipsilateral: An Analysis of Tibial Tunnel Distance Between Cruciate Ligament Reconstruction and Posterior Meniscal Root Repair

Purpose

To establish mean distance or identify intersection between tibial tunnels for posterior meniscal root repair in the setting of anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) reconstruction.

Methods

Twelve cadaver knees and 12 solid foam synthetic tibiae were used. ACL and PCL tunnels were drilled for single-bundle reconstruction, and both medial and lateral posterior root repair tunnels were drilled. Specimens underwent computed tomography scanning and shortest distances between tunnels in all planes were measured by 2 readers. Distances were compared between groups using a t-test.

Results

In ACL reconstruction, the medial meniscal root tunnel was not significantly closer to the cruciate tunnel when drilled from either medial or lateral side (P = .333). The lateral meniscal root tunnel was significantly closer when drilled from medial compared to lateral side (P < .001). In PCL reconstruction, both medial (P = .037) and lateral (P = .028) meniscal root tunnels were significantly closer to the PCL tunnel when drilled from the contralateral side of the tibia.

Conclusion

This study demonstrates that posterior meniscal root repair tunnels are often placed within a few millimeters and can even intersect cruciate ligament reconstruction tunnels in the proximal tibia.

Clinical Relevance

The information in this study may assist surgeons in planning for cruciate ligament reconstruction with concomitant posterior meniscal root repair.

Meniscal Ramp Lesions and Root Tears: A Review of the Current Literature

The importance of the menisci in providing joint stability and their role in load transmission within the knee are well understood. A growing body of literature has emerged on 2 distinct injury patterns to these crucial anatomic structures, ramp lesions and root tears. Ramp lesions may be characterized as tears at the posterior meniscocapsular junction, while root tears involve bony or soft tissue avulsion of the meniscal insertions at the anterior or posterior intercondylar regions. In this 2-part review, we present an overview of the current available literature on ramp lesions and meniscal root tears, summarizing the unique anatomic considerations, etiology, biomechanics, management decisions, clinical outcomes pertinent to these very distinct injuries.

Functional, Magnetic Resonance Imaging, and Second-Look Arthroscopic Outcomes After Pullout Repair for Avulsion Tears of the Posterior Lateral Meniscus Root

BACKGROUND

Little data exist in the literature regarding second-look arthroscopic outcomes after pullout repair for avulsion tears of the posterior lateral meniscus root.

PURPOSE

To (1) assess the functional, magnetic resonance imaging (MRI), and second-look arthroscopic outcomes after pullout repair for avulsion tears of the posterior lateral meniscus root; (2) determine which demographic and clinical factors influenced healing of the repaired posterior lateral meniscus root; and (3) compare outcomes between different meniscal healing status groups.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 31 patients underwent pullout repair for avulsion tears of the posterior lateral meniscus root and had a minimum 2-year follow-up. Functional outcomes were assessed using patient-reported scores (Lysholm, Tegner, and International Knee Documentation Committee [IKDC] scores). Lateral meniscal extrusion, cartilage degeneration of the lateral compartment, and healing of the repaired posterior lateral meniscus root were assessed via MRI. The healing status was also assessed using second-look arthroscopic surgery, and the patients were divided into different healing status groups.

RESULTS

The postoperative patient-reported scores improved significantly compared with the preoperative values (P = .001). Lateral meniscal extrusion was reduced significantly from 3.37 ± 0.82 mm preoperatively to 0.63 ± 0.80 mm at final follow-up (P = .001). The grade of cartilage degeneration of the lateral compartment progressed from 0.69 ± 0.67 preoperatively to 0.95 ± 0.83 at final follow-up (P = .213). MRI scans showed complete healing in 28 patients (90.3%) and partial healing in 3 patients (9.7%). Second-look arthroscopic surgery showed stable healing in 18 of 23 patients (78.3%) and lax healing in 5 of 23 patients (21.7%). Patients with stable healing had significantly higher Lysholm and IKDC scores, more reduction of meniscal extrusion, and less progression of cartilage degeneration than did patients with lax healing (P < .05). Concomitant anterior cruciate ligament reconstruction was found to significantly positively influence healing of the repaired posterior lateral meniscus root (P = .047).

CONCLUSION

Pullout repair for avulsion tears of the posterior lateral meniscus root yielded significantly improved patient-reported scores, reduced meniscal extrusion, and a satisfactory healing rate at final follow-up. Patients with stable healing had significantly better functional and MRI outcomes than did patients with lax healing.

Editorial Commentary: False-Positive Meniscus Pseudotear on Magnetic Resonance Imaging: A False Sign That Rings True

The false-positive finding of anterior horn meniscus (pseudo)tear on magnetic resonance imaging (MRI) is an important finding of which to be aware. We have recently seen awareness similarly raised regarding root tears of the meniscus, which, if overlooked, could have detrimental consequences. Manifestations of the MRI finding of meniscus pseudotear arise from the variability of the insertion of the transverse geniculate ligament into the anterior horn of the lateral meniscus. Bearing in mind that anterior knee pain is a common reason that patients present for an orthopaedic and sports medicine evaluation, the understanding that this MRI finding does not represent a true meniscus tear may save patients from unnecessary arthroscopic surgery.

Three-dimensional and 3-Tesla MRI morphometry of knee meniscus in normal and pathologic state

INTRODUCTION

To conduct a morphometric analysis of intact and torn menisci using isotropic meniscus plane three-dimensional (3D) reconstructions on 3-Tesla MRI and compare 2D versus 3D MRI for meniscus tear characterization.

MATERIALS AND METHODS

One hundred thirty three normal menisci from 92 patients (39 male, 53 female), and 38 arthroscopy-proven torn menisci from 36 patients (23 male, 13 female) were evaluated using 3D isotropic multi-planar MRI reconstructions and 2D MRI. Two observers measured the tibial plateau height and area, meniscal height, axial plane cross-sectional areas, and extrusion of intact menisci. Two observers also measured the meniscal tear length, tear area, and residual area of pathological menisci on 2D and 3D MRI. Intraclass correlation coefficients (ICC) were obtained. Institutional Review Board approval was obtained, and the informed consent was waived.

RESULTS

Medial meniscus (MM) and lateral meniscus (LM) areas were 503.6 ± 85.1 mm² and 396.6 ± 72.0 mm² for Observer 1, and 515.8 ± 82.1 mm² and 408.0 ± 68.3 mm² for Observer 2 (ICC:0.86, 0.87). In torn menisci, average tear length, area, and residual area were 36.3 ± 13.6 mm, 182.6 ± 139.3 mm² , and 235.4 ± 140.3 mm² , respectively for Observer 1, and 38.9 ± 14.7 mm, 181.2 ± 135.6 mm² , 238.2 ± 140.5 mm² for Observer 2. In the MM and LM, bucket-handle and complex tears were largest in areas, respectively. ICCs were excellent (0.91-1.0) on 3D MRI and moderate-good (0.57-0.81) on 2D MRI.

CONCLUSION

Meniscus morphometry on 3D MRI shows moderate to excellent inter-observer reliability and meniscus tear extent is more reliably defined on 3D MRI than 2D MRI. Residual meniscus-area calculation can be performed on 3D MRI.

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.

Meniscal Root Injuries

Meniscal root tears are an increasingly recognized injury leading to notable functional limitations, potential rapid cartilage deterioration of the affected compartment, and subsequent risk of total knee arthroplasty if left untreated. Repair of these tears is advised when articular cartilage remains intact because both medial and lateral meniscus root repairs have demonstrated favorable results. Recent literature demonstrates decreased rates of osteoarthritis and arthroplasty after medial meniscus root repair compared with partial meniscectomy and nonsurgical management. The transtibial pull-out repair technique is most commonly used and provides a biomechanically strong suture construct with standard and familiar knee arthroscopy portals. Furthermore, repair has recently been shown to be economically effective by decreasing overall societal healthcare costs when compared with more conservative management strategies. This review outlines the evaluation, treatment, and documented outcomes of meniscal root repair, which is imperative to the preservation of knee function and maintaining quality of life.

Medial Versus Lateral Meniscus Root Tears: Is There a Difference in Injury Presentation, Treatment Decisions, and Surgical Repair Outcomes?

PURPOSE

To determine (1) the demographic characteristics as well as radiographic findings of medial versus lateral meniscal root tears at time of presentation, (2) treatment decisions and clinical outcomes of patients undergoing medial versus lateral root repair, and (3) risk factors for worse clinical and radiographic outcomes.

METHODS

A retrospective review was performed to identify patients with symptomatic, medial, or lateral meniscus posterior root tears with a minimum 2-year follow-up. Radiographs were graded using Kellgren-Lawrence scores. Subanalysis was performed on 62 patients who underwent root repair. Tegner, Lysholm, International Knee Documentation Committee scores, and progression to arthroplasty were analyzed in the repair groups. Patient demographics, radiographic findings, and clinical outcomes were compared between medial meniscus posterior horn root tear (MMRT) and lateral meniscus root repair (LMRT).

RESULTS

Of the 141 root tears, 109 were MMRTs, 30 were LMRTs, and 2 patients had both. At the time of injury, patients with MMRTs had a significantly higher age (MMRT = 51.4 vs LMRT=24.6, P < .0001), body mass index (MMRT = 32.1 vs LMRT 25.8, P < .0001), Kellgren-Lawrence score (MMRT = 1.3 vs LMRT=0.6, P < .0001), and higher rate of major meniscal extrusion (MMRT = 72% vs LMRT = 20%, P < .0001). Of the 30 LMRT, 30/30 (100.0%) were treated with meniscal repair. With MMRT, 52/109 (48%) were treated nonoperatively, 27/109 (25%) with partial meniscectomy, and 30/109 (27%) with meniscal repair. Sixty-two patients underwent meniscus root repair with an average 41-month follow-up. LMRT had significantly increased International Knee Documentation Committee (LMRT = 89.5, MMRT = 80.4, P = .02) and Tegner scores (LMRT = 6.5, MMRT = 5.1, P < .05) compared with MMRT.

CONCLUSIONS

Compared with MMRTs, LMRTs occur in younger male patients with lower body mass index, less cartilage degeneration, less extrusion on magnetic resonance imaging, and more commonly with a ligament injury. Although good to excellent clinical outcomes were attained in select patients for both medial and lateral meniscus root repair, LMRTs may have better results after repair, suggesting that differences in injury and patient characteristics may contribute to differences in these outcomes.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

Biomechanical study of medial meniscus after posterior horn injury: a finite element analysis

We established an effective finite element model of knee joint for observation of stress and displacement of meniscus related changes after medial meniscus injury. Different types of medial meniscus injury can lead to varied meniscus stress and displacement changes. Stress and displacement concentration were found in fissure tip of meniscus tear compared to normal meniscus. The posterior horn injury of medial meniscus may initiate combined injury of medial meniscus posterior horn (MMPH) and that of medial meniscus body, and combined injury of MMPH and that of lateral meniscus anterior horn; fissure expansions regarding horizontal fissure, longitudinal fissure and grip-shaped fissure of MMPH were spotted.

Different Suture Materials for Arthroscopic Transtibial Pull-out Repair of Medial Meniscal Posterior Root Tears: A Human Biomechanical Study

Background

Transtibial pull-out repair of the medial meniscal posterior root (MMPR) has been largely assessed through biomechanical studies. Biomechanically comparing different suture types would further optimize MMPR fixation and affect clinical care.

Purpose/Hypothesis

The purpose of this study was to determine the optimal suture material for MMPR fixation. It was hypothesized that ultra high-molecular weight polyethylene (UHMWPE) suture tape would be biomechanically superior to UHMWPE suture and standard suture.

Study Design

Controlled laboratory study.

Methods

The MMPR attachment was divided in 24 human cadaveric knees and randomly assigned to 3 repair groups: UHMWPE suture tape, UHMWPE suture, and standard suture. Specimens were dissected down to the medial meniscus, and the posterior root attachments were sectioned off the tibia. Two-tunnel transtibial pull-out repair with 2 sutures, as determined by the testing group, was performed. The repair constructs were cyclically loaded between 10 and 30 N at 0.5 Hz for 1000 cycles to mimic the forces experienced on the medial meniscus during postoperative rehabilitation. Displacement was recorded at 1, 50, 100, 500, and 1000 cycles. Ultimate failure load, displacement at failure, and load at 3 mm of displacement (clinical failure) were also recorded.

Results

UHMWPE suture tape had significantly less displacement of the medial meniscus when compared with standard suture at 1 (-0.22 mm [95% CI, -0.41 to -0.02]; P = .025) and 50 (-0.35 mm [95% CI, -0.67 to -0.03]; P = .029) cycles. There were no other significant differences observed in displacement between groups at any number of cycles. UHMWPE suture tape had significantly less displacement at the time of failure than standard suture (-3.71 mm [95% CI, -7.17 to -0.24]; P = .034). UHMWPE suture tape had a significantly higher load to reach the clinical failure displacement of 3 mm than UHMWPE suture (15.64 N [95% CI, 0.02 to 31.26]; P = .05). There were no significant differences in ultimate failure load between groups.

Conclusion

The meniscal root repair construct with UHMWPE suture tape may be stronger and less prone to displacement than that with standard suture or UHMWPE suture.

Clinical Relevance

UHMWPE suture tape may provide better clinical results compared with UHMWPE suture and standard suture.

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).

Editorial Commentary: Meniscal Root Repairs: Let the Biology Help You!

Meniscal root tears are increasingly being recognized as important entities by the orthopaedic community. This is probably due to the catastrophic consequences of not identifying or addressing a root tear in a timely fashion, leading to the need for a total meniscectomy. The majority of the studies on root tears have been focused on natural history, diagnosis, biomechanical consequences, and fixation techniques. Conversely, rehabilitation concepts have been extrapolated from those applied after other meniscal tears/repairs, even though root tears probably constitute a completely different pathology from biological and biomechanical standpoints. Time zero studies are important to determine the effect of certain loads on the repaired structure without taking into consideration the healing process. This allows for examination of the effects that an accelerated protocol would have in the immediate postoperative phase after a root repair. As with any repaired structure, allowing time for the repaired tissue to heal is vital because failing to do so might lead to unrecoverable failure of the root fixation.

Injury patterns of medial meniscus posterior root tears

INTRODUCTION

Medial meniscus posterior root tear (MMPRT) can occur in middle-aged patients who have a posteromedial painful popping during light activities. MMPRTs are more common in patients with increased age, female gender, sedentary lifestyle, obesity, and varus knee alignment. However, injury mechanisms of minor traumatic MMPRTs are still unclear. We hypothesized that high flexion activities are the major cause of MMPRTs. The aim of this study was to clarify injury patterns of MMPRTs.

MATERIALS AND METHODS

One hundred patients were diagnosed having MMPRTs after posteromedial painful popping episodes. Details of posteromedial painful popping episode, situation of injury, and position of injured leg were obtained from the patients by careful interviews. Injury patterns were divided into 8 groups: descending knee motion, walking, squatting, standing up action, falling down, twisting, light exercise, and minor automobile accident.

RESULTS

A descending knee motion was the most common cause of MMPRTs (38%) followed by a walking injury pattern (18%) and a squatting action related to high flexion activities of the knee (13%). The other injury patterns were less than 10%.

DISCUSSION

Descending knee motions associated with descending stairs, step, and downhill slope are the most common injury pattern of MMPRTs. High flexion activities of the knee are not the greatest cause of MMPRTs. Our results suggest that the descending action with a low knee flexion angle may trigger minor traumatic MMPRTs.

LEVEL OF EVIDENCE

IV, retrospective cohort study.