Meniscal Height Research Articles

Utility of Adult-Based Discoid Lateral Meniscus Diagnostic Criteria in a Pediatric Population.

Commonly cited discoid lateral meniscus (DLM) imaging definitions are based on adult magnetic resonance imaging (MRI) measurements. This pathology commonly presents in pediatric populations; however, whether accepted adult measurements reliably apply to children and adolescents is unknown. This purposes of the study were to determine (1) the utility of applying adult-accepted MRI definitions of DLM to pediatric patients, (2) whether sex differences affect the applicability of the criteria, and (3) whether MRI magnet strength and/or tear presence affect MRI measurements for diagnosing DLM in pediatric patients. It was hypothesized that MRI criteria for DLM would be similar in adults and pediatric patients. Case series; Level of evidence, 4. A total of 100 consecutive MRIs from pediatric patients with DLM were evaluated, with 91 scans included. Two study authors independently reviewed the MRIs, evaluating meniscal height and width on sagittal and coronal images, "bow tie signs" on sagittal images, tibial sagittal and coronal width, and tear presence. For analysis, MRI magnet strength was dichotomized into high (>1.5 T) and low (<1.5 T) groups. The mean age of the patients at MRI evaluation was 12.3 ± 3.4 years; 51% of the patients were male, and 56% of the scans were of left knees. Included patients with DLM showed a mean of 3.68 bow tie signs, a sagittal total anterior to posterior meniscal width/tibial width ratio of 73%, a coronal meniscal width/tibial width ratio of 30%, and a coronal, transverse width of the lateral meniscus at the midportion of the meniscal body of 20.6 ± 7.7 mm. The MRI tesla strength of the images included in this study ranged from 0.3 to 3. It was determined that high- versus low-resolution MRI scans did not affect the inter- or intraobserver reliability of the MRI measurments (P > .05). However, several measurements showed improved intraclass correlation coefficients with increased tesla strength. This study confirms that pediatric patients with DLM, diagnosed by board-certified pediatric sports medicine orthopaedic surgeons, have measurements on MRI consistent with adult DLM diagnostic criteria. This finding held true regardless of sex or MRI tesla strength. Pediatric patients with DLM had >3 bow tie signs, >70% sagittal tibial plateau coverage, >14 mm coronal width, and >20% coronal tibial plateau coverage on MRI.

Evaluation of Medial Meniscal Extrusion Using Radiography.

Recently, there has been increasing interest in medial meniscal extrusion (MME), but few reports have evaluated MME via X-ray. In this study, the amount of MME and meniscal height at the medial border of the tibia were measured via X-ray with gradation processing. The extrusion length divided by the meniscal height yields the meniscal extrusion ratio, which was used as an index. In addition, the medial meniscal length of the part protruding from the medial border of the tibia on MRI was measured as an absolute value. Then, the correlation between the meniscal extrusion ratio and the amount of MME on MRI was examined, and there was a strong correlation between the meniscal extrusion ratio via X-ray and the amount of MME on MRI (correlation coefficient 0.860, p < 0.0001). The cut-off value of the meniscal extrusion ratio via X-ray for positive meniscal extrusion on MRI was 0.50, with an AUC of 0.9825, sensitivity of 0.9063, and specificity of 0.8663. From the present study, it was possible to measure the extrusion length and meniscal height via gradation processing, with X-ray and without MRI, and to calculate the meniscal extrusion ratio, which strongly correlates with the amount of MME on MRI.

Knee anatomic geometry accurately predicts risk of anterior cruciate ligament rupture.

Certain anatomical characteristics of the knee have potential relationships with the risk of anterior cruciate ligament (ACL) rupture. There remains a need for stronger evidence using arthroscopy as well as radiological imaging to accurately clarify these relationships. To compare the anatomic geometry of the knee joint between patients with and without ACL ruptures. Case-controlled study of patients with arthroscopically confirmed ACL ruptures (ACL group) compared to patients with arthroscopically confirmed normal ACLs (control group). Magnetic resonance imaging scans were assessed for a total of 14 quantitative radiological variables including medial and lateral tibial slope angles (bone and cartilage measurements), meniscal height, femoral width, intercondylar notch width and tibial depth. A total of 105 patients were included in the study, 55 in the ACL group and 50 in the control group. There was a significant difference (P < 0.05) of most of the radiological measurements between the two groups. There was also a significant difference (P < 0.05) when comparing the variables between sexes. Multiple logistic regression analysis produced a mathematical model utilizing all the radiological measurements with 92.6% classification accuracy in predicating an ACL rupture with the medial tibial slope angle being the strongest predicator variable (odds ratio = 8.97, P = 0.011). Greater postero-inferior directed slope measurements of bone and cartilage in both the lateral and medial compartments with a narrower intercondylar notch width increase the risk of ACL rupture. Mathematical modelling can accurately predict the risk of ACL rupture.

Magnetic Resonance Image (Mri) Measurements of Lateral Discoid Meniscus (Ldm) in Pediatric Patients Match Adult Lateral Discoid Meniscus Definitions

Background:Commonly cited lateral discoid meniscus (LDM) imaging definitions are based upon adult MRI measurements: >70% tibial plateau coverage on the sagittal, >20% tibial plateau coverage on the coronal and >3 bowtie signs. This pathology more commonly presents in pediatric populations and it is unknown if these measurements apply to a pediatric population. Therefore, it is important to understand the Magnetic Resonance Image (MRI) measurements of LDM in a pediatric population.Hypothesis/Purpose:The purpose of this study is to define LDM measurements on MRI in a pediatric population. Authors hypothesize there is a wide variation in LDM characteristics on MRI.Methods:100 MRIs on LDM patients who are skeletally immature were evaluated and 91 included in this study. Demographics were recorded. Two study authors independently reviewed MRIs measuring meniscal height and width on sagittal and coronal images, tear presence, number of “bowties” on sagittal images, as well as tibial sagittal and coronal width. One study author repeated measurements a minimum of 4 weeks after initial review. Figure 1 describes each measurement. Statistical analysis was performed using fisher’s exact test for differences, as well as multinomial, linear and logistic regression models with clustered robust standard errors.Results:Average age at MRI was 12.3 ± 3.4 years, 51% male, 56% left knees. Table 1 reports gender comparison of MRI measurements. Table 2 reports gender comparison of bowtie sign and ratios of meniscal width to tibial width on coronal and sagittal images. Tears were reported in 72 MRIs (80%). Genders of patients with tears were not statistically different (Female: N=33; 73%, Male: N=39; 87%, p=0.16). Sagittal anterior (p=0.005) meniscal width, anterior to posterior meniscal width (p<0.001), and # of bowtie signs (p=0.043) were significantly associated with tear presence.Conclusion:MRI characteristics can aide in accuracy of LDM diagnosis. Pediatric patients with diagnosed discoid meniscus had >3 bowtie signs, >70% tibial plateau coverage on the sagittal, and >20% tibial plateau coverage on the coronal consistent with adult reported definitions of discoid meniscus.Figure 1.Description of MRI measurementsMeasurements of the lateral meniscus on the (a) sagittal plane and (b) coronal plane. Sagittal plane image in the mid-condylar slice shows: (4) total anterior to posterior meniscus distance, (5) anterior horn height, (6) posterior horn height, and (7) sagittal tibial width. Coronal plane image shows: (9) meniscus coronal width, (10) meniscus coronal height, and (11) coronal tibial width.Table 1.Gender comparison of MRI measurementsTable 2.Gender comparison of bowtie sign and ratios of meniscal width to tibial width

Meniscal anterior and posterior horn heights are associated with MRI-defined knee structural abnormalities in middle-aged and elderly patients with symptomatic knee osteoarthritis

BackgroundMeniscal morphological changes are associated with knee OA. However, the correlation of meniscal height and OA-related knee structural abnormalities is still not well understood. The purpose of present study is to investigate whether and how meniscal anterior and posterior horn heights are associated with structural abnormalities in knees with symptomatic OA.MethodsOur sample consisted of 106 patients (61 female, aged 40–73 years) with symptomatic knee OA. Kellgren-Lawrence system was used for radiographic evaluation. On sagittal sequence, medial meniscal posterior horn height (MPH), lateral meniscal anterior horn height (LAH) and lateral meniscal posterior horn height (LPH) were measured on the middle slice through the medial/lateral compartment. Knee structural abnormalities were assessed using the modified whole-organ magnetic resonance imaging score (WORMS). Associations between meniscal anterior and posterior horn heights and knee structural abnormalities were assessed using linear regression analysis.ResultsHigher MPH was significantly associated with higher WORMS score for medial meniscal anterior horn lesion (P = 0.016) but did not have a statistical association with other WORMS parameters. Increased LAH was statistically correlated with decreased WORMS scores for lateral compartmental cartilage lesions (P = 0.001–0.004) and lateral compartmental bone marrow edema patterns (BMEPs) (P = 0.021–0.027). Moreover, LPH was negatively associated with WORMS scores for lateral compartmental cartilage lesions (P = 0.007–0.041) and lateral compartmental BMEPs (P = 0.022–0.044). Additionally, higher MPH was statistically associated with lower trochlea cartilage WORMS score and higher LAH was significantly correlated with higher WORMS score for trochlea subarticular cysts.ConclusionsChanges of LAH and LPH were inversely associated with the severity of lateral compartmental cartilage lesions and BMEPs, while higher MPH was only significantly correlated with more severe medial meniscal anterior horn lesions. Besides, MPH and LAH were also significantly associated with patellofemoral structural abnormalities. The present study provided novel information for understanding the role of meniscal morphological changes in knee OA, which would be helpful in identifying and evaluating knees with or at risks for OA.

Reliability of a New Arthroscopic Discoid Lateral Meniscus Classification System: A Multicenter Video Analysis

Background: The discoid lateral meniscus (DLM) is one of the most common congenital anomalies of the knee. The pathomorphology of DLM varies. Current classification systems are inadequate to describe the spectrum of abnormality. Purpose: A study group of pediatric orthopaedic surgeons from 20 academic North American institutions developed and tested the reliability of a new DLM classification system. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: After reviewing existing classifications, we developed a comprehensive DLM classification system. Four DLM features were evaluated: meniscal width, meniscal height, peripheral stability, and meniscal tear. Stepwise arthroscopic examination using anteromedial and anterolateral viewing portals was established for evaluating these features. Three senior authors who were not observers selected 50 of 119 submitted videos with the best clarity and stepwise examination for reading. Five observers performed assessments using the new classification system to assess interobserver reliability, and a second reading was performed by 3 of the 5 observers to assess intraobserver reliability using the Fleiss κ coefficient (fair, 0.21-0.40; moderate, 0.41-0.60; substantial, 0.61-0.80; excellent, 0.81-1.00). Results: Interobserver reliability was substantial for most rating factors: meniscal width, meniscal height, peripheral stability, tear presence, and tear type. Interobserver reliability was moderate for tear location. Intraobserver reliability was substantial for meniscal width and meniscal height and excellent for peripheral stability. Intraobserver agreement was moderate for tear presence, type, and location. Conclusion: This new arthroscopic DLM classification system demonstrated moderate to substantial agreement in most diagnostic categories analyzed.

A Prediction Model for Primary Anterior Cruciate Ligament Injury Using Artificial Intelligence.

Background:Supervised machine learning models in artificial intelligence (AI) have been increasingly used to predict different types of events. However, their use in orthopaedic surgery has been limited.Hypothesis:It was hypothesized that supervised learning techniques could be used to build a mathematical model to predict primary anterior cruciate ligament (ACL) injuries using a set of morphological features of the knee.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Included were 50 adults who had undergone primary ACL reconstruction between 2008 and 2015. All patients were between 18 and 40 years of age at the time of surgery. Patients with a previous ACL injury, multiligament knee injury, previous ACL reconstruction, history of ACL revision surgery, complete meniscectomy, infection, missing data, and associated fracture were excluded. We also identified 50 sex-matched controls who had not sustained an ACL injury. For all participants, we used the preoperative magnetic resonance images to measure the anteroposterior lengths of the medial and lateral tibial plateaus as well as the lateral and medial bone slope (LBS and MBS), lateral and medial meniscal height (LMH and MMH), and lateral and medial meniscal slope (LMS and MMS). The AI predictor was created using Matlab R2019b. A Gaussian naïve Bayes model was selected to create the predictor.Results:Patients in the ACL injury group had a significantly increased posterior LBS (7.0° ± 4.7° vs 3.9° ± 5.4°; P = .008) and LMS (–1.7° ± 4.8° vs –4.0° ± 4.2°; P = .002) and a lower MMH (5.5 ± 0.1 vs 6.1 ± 0.1 mm; P = .006) and LMH (6.9 ± 0.1 vs 7.6 ± 0.1 mm; P = .001). The AI model selected LBS and MBS as the best possible predictive combination, achieving 70% validation accuracy and 92% testing accuracy.Conclusion:A prediction model for primary ACL injury, created using machine learning techniques, achieved a >90% testing accuracy. Compared with patients who did not sustain an ACL injury, patients with torn ACLs had an increased posterior LBS and LMS and a lower MMH and LMH.

The association of meniscal body height with knee structural changes in middle-aged and elderly patients with symptomatic knee osteoarthritis.

To investigate whether and how meniscal height is associated with osteoarthritis (OA)-related knee structural changes in symptomatic knee OA. We studied 106 patients (61 female, aged 40-73 years) with symptomatic knee OA. X-ray was used for Kellgren-Lawrence score. Meniscal body heights and extrusion were measured on coronal sections of intermediate-weighted MRI sequence. Knee structural changes were assessed using the modified whole-organ magnetic resonance imaging score (WORMS). Associations between meniscal body height and knee structural changes were assessed using linear regression analysis. Higher medial meniscal body height was significantly associated with severe medial meniscal lesions (p = 0.001-0.023), medial compartmental cartilage lesions (p = 0.045), patellofemoral compartmental and medial compartmental bone marrow edema patterns (p = 0.001-0.037), anterior cruciate ligament and patellar ligament abnormalities (p = 0.020-0.023), and loose bodies (p = 0.017). However, lateral meniscal body height was negatively correlated with WORMS scores for lateral meniscal lesions (p ≤ 0.018), lateral compartmental cartilage lesions (p ≤ 0.011), and lateral compartmental bone marrow edema patterns (p = 0.038). Higher medial meniscal body height was associated with more severe medial compartment structural abnormalities and patellofemoral bone marrow edema patterns, while lateral meniscal body height was inversely correlated with the severity of lateral compartment structural abnormalities. Our study revealed that meniscal body height was associated with multiple OA-related knee structural changes, which would be beneficial in identifying patients with or at risks for knee OA.

Variations of cross-sectional meniscal morphology between similar-sized menisci: implications on donor selection for meniscal allograft transplantation.

This study aimed to investigate the morphological variations in the cross-sectional anatomy of the meniscus between similar-sized matched menisci. Knee MRI of 329 patients with intact menisci were retrospectively reviewed, and the meniscal length (ML), meniscal width (MW), and cross-sectional dimensions (meniscal height and width) of the anterior, posterior horns, and the corpus were measured. Patients with similar-sized menisci who had less than 1mm difference in ML and MW were matched. 330 male-to-male medial menisci (MM), 623 male-to-male lateral menisci (LM), 82 female-to-female MM, 233 female-to-female LM, 176 cross-gender MM, and 265 cross-gender LM unique combination of ideally matched pairs (total: 1709) were generated. The disparity in the cross-sectional dimensions, absolute difference, and the paired percent differences was statistically analyzed. The ML and MW in all groups were statistically similar, with a predefined absolute difference of 1mm both for ML and MW (paired percent difference < 5%). The cross-sectional segmental meniscal dimensions were similar within all groups, but the paired percent differences showed high variations between a mean of 12.1-21.5% and up to 150.9%. The paired percent difference of MM in each segmental dimension was similar among different gender combinations. However, segmental paired percent differences of LM showed statistical differences in anterior horn width (AHW) (p: 0.001) and posterior horn width (PHW) (p: 0.001). In subgroup comparisons, the paired percent difference of AHW was higher in the female-to-female group compared to cross-gender (p: 0.023) and male-to-male groups (p: 0.001). The paired percent difference of PHW was smaller in the male-to-male group compared to female-to-female and cross-gender groups (p: 0.001 for both). Segmental cross-sectional anatomy showed wide variations despite strict matching in ML and MW. These variations were present in all gender combinations. The meniscal 3D shape is unique, but acceptable limits of similarity need further research. Retrospective study, Level III.

Lateral Meniscus Height and ACL Reconstruction Failure: A Nested Case-Control Study.

Previous work has shown that the morphology of the knee joint is associated with the risk of primary anterior cruciate ligament (ACL) injury. The objective of this study is to analyze the effect of the meniscal height, anteroposterior distance of the lateral tibial plateau, and other morphological features of the knee joint on risk of ACL reconstruction failure. A nested case-control study was conducted on patients who underwent an ACL reconstruction surgery during the period between 2008 and 2015. Cases were individuals who failed surgery during the study period. Controls were patients who underwent primary ACL reconstruction surgery successfully during the study period. They were matched by age (±2 years), gender, surgeon, and follow-up time (±1 year). A morphological analysis of the knees was then performed using the preoperative magnetic resonance imaging scans. The anteroposterior distance of the medial and lateral tibial plateaus was measured on the T2 axial cuts. The nonweightbearing maximum height of the posterior horn of both menisci was measured on the T1 sagittal scans. Measurements of the medial and lateral tibial slope and meniscal slope were then taken from the sagittal T1 scans passing through the center of the medial and lateral tibial plateau. A binary logistic regression analysis was done to calculate crude and adjusted odds ratios (ORs) estimates. Thirty-four cases who underwent ACL revision surgery were selected and were matched with 68 controls. Cases had a lower lateral meniscal height (6.39 ± 1.2 vs. 7.02 ± 0.9, p = 0.008, power = 84.4%). No differences were found between the two groups regarding the bone slope of the lateral compartment (6.19 ± 4.8 vs. 6.92 ± 5.8, p = 0.552), the lateral meniscal slope (-0.28 ± 5.8 vs. -1.03 ± 4.7, p = 0.509), and the anteroposterior distance of the lateral tibial plateau (37.1 ± 5.4 vs. 35.6 ± 4, p = 0.165). In addition, no differences were found in the medial meniscus height between cases and controls (5.58 ± 1.2 vs. 5.81 ± 1.2, respectively, p = 0.394). There were also no differences between cases and controls involving the medial bone slope, medial meniscal slope, or anterior posterior distance of the medial tibial plateau. Female patients had a higher medial (4.8 degrees ± 3.2 vs. 3.3 ± 4.1, p = 0.047) and lateral (8.1 degrees ± 5.1 vs. 5.6 degrees ± 5.6, p = 0.031) tibial bone slope, and a lower medial (5.3 mm ± 1.0 vs. 6.1 mm ± 1.2, p = 0.001) and lateral (6.6 ± 1.0 vs. 7.0 ± 1.2, p = 0.035) meniscus height, and medial (4.3 ± 0.4 vs. 4.8 ± 0.4, p =0.000) and lateral (3.3 ± 0.3 vs. 3.9 ± 0.4, p = 0.000) anteroposterior distance than males, respectively.The adjusted OR of suffering an ACL reconstruction failure compared to controls was 5.1 (95% confidence interval [CI]: 1.7-14.9, p = 0.003) for patients who had a lateral meniscus height under 6.0 mm. The adjusted OR of suffering an ACL reconstruction failure was 2.4 (95% CI: 1.0-7.7, p = 0.01) for patients who had an anteroposterior distance above 35.0 mm. Patients with a lateral meniscal height under 6.0 mm have a 5.1-fold risk of suffering an ACL reconstruction failure compared to individuals who have a lateral meniscal height above 6.0 mm. Patients with a higher anteroposterior distance of the lateral tibial plateau also have a higher risk of ACL reconstruction failure.

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

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. 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. 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. 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.

INTEROBSERVER RELIABILITY OF A COMPREHENSIVE LATERAL DISCOID MENISCUS CLASSIFICATION SYSTEM: A MULTICENTER ARTHROSCOPIC VIDEO ANALYSIS STUDY

Introduction/Background:Lateral discoid meniscus (LDM) is the most common congenital anomaly of the knee. Due to the significant heterogeneity in pathomorphology, LDM treatment remains challenging. Treatment approaches and surgical techniques vary widely among surgeons and different types of LDM. Current classification systems inadequately describe the spectrum of pathology or dictate treatment.Hypothesis/Purpose:The Pediatric Research in Sports Medicine (PRISM) meniscal study group developed and tested the reliability of a novel classification system designed to comprehensively capture the intricacies of LDM pathomorphology and guide treatment decisions.Methods:The PRISM LDM Classification System was developed through an initial review of existing classification systems followed by group consensus method by pediatric meniscal surgeons from 20 tertiary academic centers. Four factors were evaluated: (1) meniscal width (surface area), (2) meniscal height (thickness, +/- horizontal delamination), (3) peripheral stability (and instability pattern), and (4) tearing (and tear location)(Table 1). A stepwise arthroscopic exam utilizing two standard anterior viewing portals was established for optimizing diagnosis of LDM features.From a set of 101 arthroscopic videos submitted for review, 41 were selected for quality by 3 of the authors (non-’readers’). Five ‘readers’ then performed assessments using the classification system. Interobserver reliability of the primary and secondary rating factors was assessed using the Fleiss kappa coefficient (K, 95% CI), designed for multiple readers with nominal variables (Reliability Classification: Fair 0.21-0.40 fair, Moderate 0.41-0.60, Substantial 0.61-0.80, and Excellent 0.80-1.00).Results:The majority of the primary and secondary rating factors demonstrated ‘substantial’ reliability, such as meniscal width (complete vs. incomplete, K 0.609; 0.512-0.706) and posterior horn stability (stable vs. unstable, K 0.693; 0.594-0.792), or ‘moderate’ reliability, such as meniscal height (normal vs. abnormal, K 0.444; 0.347-0.541), overall stability, (stable vs. unstable, K 0.569; 0.472-0.666), and tear presence (tear vs. no tear, K 0.541; 0.444-0.638).Several features demonstrated only ‘fair’ agreement, including anterior horn stability (stable vs. unstable, K 0.358; 0.258-0.457), meniscal body stability (stable vs. unstable, K 0.314; 0.214-0.413), and tear type (no tear, radial, vertical, complex, K 0.386; 0.325-0.446).Conclusion/Discussion:A novel classification system that more comprehensively and descriptively characterizes the spectrum of LDM pathology demonstrated moderate or substantial agreement in most diagnostic categories analyzed. Specific features demonstrating fair agreement may warrant investigation of alternative steps in the arthroscopic exam or descriptors to improve agreement. A comprehensive classification system is critical to advance LDM research from single-center, level 4 studies to prospective multicenter efforts that will enhance improve communication, research, and evidence-based treatment of LDM pathology.

Discoid meniscus in children and adolescents: Correlation between morphology and meniscal tears

BackgroundSome authors have suggested that the diminished vascular blood supply, peripheral stability and thickness of the discoid meniscus (DM) would make it more prone to tears. The aims of this study are two-fold: (1) To analyse morphological characteristics by magnetic resonance (MRI), and (2) To correlate the size of the meniscus with the presence of meniscal tears. MethodsThe MRI of patients ≤18 years-old over a period of 5 years were reviewed, and patients with DM were identified. We analysed demographic data, location (medial or lateral), morphology (Watanabe), meniscal tears (Crues classification), pattern, displacement, and other associated findings. Meniscal height and thickness per width (TxW) were also calculated. The correlation between variables: morphology, height and TxW with the presence of meniscal tears were statistically analysed. ResultsSix hundred and eighty-five MRI (675 patients) were analysed. Forty-three knees (38 patients, 20 males) were found to have a DM (6.3%). The average age was 12.2±3.8 years (range: 4–18 years). Sixty-three percent had some type of meniscal injury. Patients with complete MD had a higher incidence of injuries (77.3 vs. 47.6%; P=.001). Longitudinal (bucket handle) and complex tears (n=11) only occurred in patients with complete DM. DM with tears presented a nonsignificant tendency to have higher meniscal height and higher TxW (6.29±1.26 vs. 5.75±.66mm; P=.20 and 107.5±36.02 vs. 91.54±16.5mm2; P=.162). ConclusionThe results of this series support the theory that a larger meniscal size would be one of the main predisposing factors for the DM to be injured. Study designCross-sectional study (Level of evidence: III).

Quantitative and Qualitative Assessment of the Posterior Medial Meniscus Anatomy: Defining Meniscal Ramp Lesions

Background: Meniscal ramp lesions have been defined as a tear of the peripheral attachment of the posterior horn of the medial meniscus (PHMM) at the meniscocapsular junction or an injury to the meniscotibial attachment. Precise anatomic descriptions of these structures are limited in the current literature. Purpose: To quantitatively and qualitatively describe the PHMM and posteromedial capsule anatomy pertaining to the location of a meniscal ramp lesion with reference to surgically relevant landmarks. Study Design: Descriptive laboratory study. Methods: Fourteen male nonpaired fresh-frozen cadavers were used. The locations of the posteromedial meniscocapsular and meniscotibial attachments were identified. Measurements to surgically relevant landmarks were performed with a coordinate measuring system. To further analyze the posteromedial meniscocapsular and meniscotibial attachments, hematoxylin and eosin and alcian blue staining were conducted on a separate sample of 10 nonpaired specimens. Results: The posterior meniscocapsular attachment had a mean ± SD length of 20.2 ± 6.0 mm and attached posteroinferiorly to the PHMM at a mean depth of 36.4% of the total posterior meniscal height. The posterior meniscotibial ligament attached on the PHMM 16.5 mm posterior and 7.7 mm medial to the center of the posterior medial meniscal root attachment. The meniscotibial ligament tibial attachment was 5.9 ± 1.3 mm inferior to the articular cartilage margin of the posterior medial tibial plateau. The posterior meniscocapsular attachment converged with the meniscotibial ligament at the most posterior point of the meniscocapsular junction in all specimens. Histological staining of the meniscocapsular and meniscotibial ligament PHMM attachments showed similar structure, cell density, and fiber directionality, with no qualitative difference in the makeup of their collagen matrices across all specimens. Conclusion: The anatomy of the area where a medial meniscal ramp tear occurs revealed that the 2 posterior meniscal attachments merged at a common attachment on the PHMM. Histological analysis validated a shared attachment point of the meniscocapsular and meniscotibial attachments of the PHMM. Clinical Relevance: The findings of this study provide the anatomic foundation for an improved understanding of the meniscocapsular and meniscotibial attachments of the PHMM, which may help provide a more precise definition of a meniscal ramp lesion.

Menisco discoide en niños y adolescentes: correlación entre la morfología y la presencia de lesiones

BackgroundSome authors have suggested that the diminished vascular blood supply, peripheral stability and thickness of the discoid meniscus (DM) would make it more prone to tears. The aims of this study are two-fold: 1) To analyse morphological characteristics by magnetic resonance (MRI), and 2) To correlate the size of the meniscus with the presence of meniscal tears. MethodsThe MRI of patients ≤18 years-old over a period of 5 years were reviewed, and patients with DM were identified. We analysed demographic data, location (medial or lateral), morphology (Watanabe), meniscal tears (Crues classification), pattern, displacement, and other associated findings. Meniscal height and thickness per width (TxW) were also calculated. The correlation between variables: morphology, height and TxW with the presence of meniscal tears were statistically analysed. ResultsSix hundred and eighty-five MRI (675 patients) were analysed. Forty-three knees (38 patients, 20 males) were found to have a DM (6.3%). The average age was 12.2±3.8 years (range: 4-18 years). Sixty-three percent had some type of meniscal injury. Patients with complete MD had a higher incidence of injuries (77.3 vs. 47.6%; P=.001). Longitudinal (bucket handle) and complex tears (n ??=11) only occurred in patients with complete DM. DM with tears presented a nonsignificant tendency to have higher meniscal height and higher TxW (6.29±1.26 vs 5.75±.66mm; P=.20 and 107.5±36.02 vs. 91.54±16.5mm2; P=.162). ConclusionThe results of this series support the theory that a larger meniscal size would be one of the main predisposing factors for the DM to be injured. Study designCross-sectional study (Level of evidence: III).

The Effects of Meniscal Geometry on Susceptibility for Meniscal and ACL Injury in Non-Arthritic Knees: A Retrospective Case-Control Study.

Prior studies have not found significant differences in meniscal parameters between patients with meniscal and ligamentous injury and those without. The purpose of this study was to determine whether such relationships exist. Clinical records and magnetic resonance images of three subject groups were reviewed. Group 1 solely had meniscal tears (medial/lateral), Group 2 had meniscal tears with concurrent ACL tears, and Group 3 had healthy knees. The mean age of subjects included was 35.9 years (range 8.2-72.6). The height, width, diagonal, slope, and cross-sectional area for the anterior and posterior horns of the lateral and medial menisci were assessed. Normal distribution of data was confirmed by the Shapiro-Wilk test and analysis of variance with a post hoc Tukey's test was used to assess potential differences. p < 0.05 was set as the level of significance. There was no difference between the meniscal slopes of patients with and without meniscal tears (p = 0.77-1.0). Meniscal height (p = 0.0001-0.024) and width (p = 0.0001-0.046) demonstrated significant differences in all horns. Cross-sectional area was larger in the torn group (p = 0.0001-0.012). To compare intact and torn menisci, a logistical regression model was used and found to be significantly different from the constant model (p < 0.0001). Predictive success was 80.5%. A logistical regression model was used comparing undamaged menisci with torn menisci with accompanying anterior cruciate ligament (ACL) tear and was significant (p < 0.0001). A larger cross-sectional meniscal area in both the anterior and posterior horns of both menisci was a risk factor for isolated meniscal tears and combined meniscal and ACL tears. It has been postulated that certain demographic variables, such as gender, age, and body mass index, may be risk factors associated with ACL and meniscal injuries. However, the relationship between intrinsic morphology, namely meniscal size and shape, and risk of injury is unclear. The majority of studies have focused on meniscal morphology/geometry and its association with degenerative tears in patients with end-stage osteoarthritis rather than on acute meniscoligamentous injury. In this study of non-arthritic knees, a larger cross-sectional meniscal area in both the anterior and posterior horns of both menisci was a risk factor for having both an isolated meniscal tear as well as a combined meniscal and ACL tear. With advances in the field of meniscal repair, particularly with allograft procedures, more attention should be paid to meniscal cross-sectional area because it may play a role in the natural history of knee injury.

Improvement in the medial meniscus posterior shift following anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction can reduce the risk of developing osteoarthritic knees. The goals of ACL reconstruction are to restore knee stability and reduce post-traumatic meniscal tears and cartilage degradation. A chronic ACL insufficiency frequently results in medial meniscus (MM) injury at the posterior segment. How ACL reconstruction can reduce the deformation of the MM posterior segment remains unclear. In this study, we evaluated the form of the MM posterior segment and anterior tibial translation before and after ACL reconstruction using open magnetic resonance imaging (MRI). Seventeen patients who underwent ACL reconstructions without MM injuries were included in this study. MM deformation was evaluated using open MRI before surgery and 3months after surgery. We measured medial meniscal length (MML), medial meniscal height (MMH), medial meniscal posterior body width (MPBW), MM-femoral condyle contact width (M-FCW) and posterior tibiofemoral distance (PTFD) at knee flexion angles of 10° and 90°. There were no significant pre- and postoperative differences during a flexion angle of 10°. At a flexion angle of 90°, MML decreased from 43.7±4.5 to 41.4±4.5mm (P<0.001), MMH from 7.5±1.4 to 6.9±1.4mm (P=0.006), MPBW from 13.1±2.0 to 12.2±1.9mm (P<0.001) and M-FCW from 10.0±1.5 to 8.5±1.5mm (P<0.001) after ACL reconstruction. The PTFD increased from 2.1±2.8 to 2.7±2.4mm after ACL reconstruction (P=0.015). ACL reconstruction affects the contact pattern between the MM posterior segment and medial femoral condyle and can reduce the deformation of the MM posterior segment in the knee-flexed position by reducing abnormal anterior tibial translation. It possibly prevents secondary injury to the MM posterior segment and cartilage that progresses to knee osteoarthritis. IV.

Should the meniscal height be considered for preoperative sizing in meniscal transplantation?

Purpose and hypothesisIn preoperative sizing for meniscal transplantation, most authors take into consideration the length and width of the original meniscus, but not its height. This study aimed at evaluating (1) whether the meniscal height is associated with the meniscal length and width, (2) whether the heights of the meniscal segments are associated with the individual’s anthropometric data, (3) whether the heights of the meniscal segments are associated with each other in the same meniscus, and (4) the degree of symmetry of the meniscal dimensions between the right and left knees.MethodsIn this cross-sectional, observational study, two independent radiologists measured the meniscal length, width and height in knee magnetic resonance imaging scans obtained from 25 patients with patello-femoral pain syndrome. Reproducibility of measurements was calculated with intraclass correlation coefficients. Associations between the anthropometric data and the meniscal measurements, the meniscal length and width versus height, and the heights of the meniscal segments in the same meniscus were examined with Pearson’s correlation.ResultsInter-observer reliability was excellent (>0.8) for length and height and good (0.6–0.8) for width measurements. There was also excellent agreement (>0.8) for the length and width of the menisci in the right and left knees. The heights of the horns of the lateral meniscus showed good agreement (0.6–0.8), while the heights of the other meniscal segments had excellent agreement between the sides (>0.8). There were significant associations with generally low (r < 0.5) correlation between the heights of the meniscal segments and the lengths and widths of the menisci, between the meniscal height and anthropometric data, and between the heights of the meniscal segments in the same meniscus. Correlations between anthropometric data and meniscal length and width were generally high (r > 0.7).ConclusionsThere was excellent agreement between the meniscal dimensions of the right and left knees, and a weak association between the meniscal height with the meniscal width and length, between the height of the menisci with anthropometric data and between the heights of the segments in the same meniscus. The height of the meniscal segments may be a new variable in preoperative meniscal measurement.

Body Mass Index, Modulated by Lateral Posterior Tibial Slope, Predicts ACL Injury Risk

Objectives:Intervention strategies to prevent ACL injury rely on increasing knowledge of risk factors. While several modifiable and non-modifiable risk factors for ACL rupture have been identified, the interaction between them remains unknown. The aim of this study was to quantify the relationship between BMI and several knee geometries as potential risk factors for ACL injury. We hypothesized that an increased BMI in the presence of an increased posterior tibial slope or middle cartilage slope would increase risk of ACL injury. We also hypothesized that an increased BMI in the presence of a decreased posterior meniscal height or meniscal bone angle would result in an increased risk of ACL injury.Methods:Sagittal knee MRI files from 76 ACL-injured and 42 non-injured subjects were gathered from the institution’s archive. The PTS, MCS, PMH, and MBA were measured using the circle method and compared with BMI from the subject demographic. Data were analyzed using univariate and multivariate logistical regression. Figure 1 details measurements made for each knee geometry.Results:Univariate analysis of PTS showed increases in PTS significantly increase the odds of ACL tear (p = 0.043, OR =1.12). Univariate analysis of MCS showed increases of MCS significantly increase the odds of ACL tear (p = 0.037, OR = 1.12). Multivariate analysis of PTS and BMI centered around the mean (PTS*cBMI) showed increases of PTS in combination with increases in cBMI significantly increases the odds of ACL rupture (p value = .050, OR = 1.03). Table 1 shows predicted increases in ACL injury risk for combinations of increases in PTS and BMI.Conclusion:An increase in BMI will increase the risk of ACL tear when an increase in lateral posterior tibial slope is present. An increase in lateral posterior tibial slope or lateral middle cartilage slope increases the risk of an ACL tear.

Single-leaf partial meniscectomy in extensive horizontal tears of the discoid lateral meniscus: Does decreased peripheral meniscal thickness affect outcomes? (Mean four-year follow-up)

BackgroundTo evaluate whether single-leaf partial meniscectomy in horizontal tears along the entire discoid lateral meniscus has any advantages in clinical and radiological results compared with other meniscectomies in discoid lateral meniscus. MethodsA total of 145 patients with a horizontal tear pattern in symptomatic lateral discoid meniscus were retrospectively reviewed. Twenty-seven patients had undergone full-extent single-leaf partial meniscectomy (group A), 60 had undergone conventional partial meniscectomy (saucerization) maintaining peripheral meniscal height (group B), and 58 patients had undergone total meniscectomy (group C). Each patient was evaluated with the Lysholm knee score, International Knee Documentation Committee (IKDC) subjective grading, and modified Kellgren–Lawrence grade in plain radiography at their last follow-up. ResultsGroup C had inferior functional results to groups A and B on the Lysholm knee score and IKDC subjective score. There was no significant difference between groups A and B. Group C fared significantly worse than groups A and B (p=0.003, p<0.001) by modified Kellgren–Lawrence grade. ConclusionWith regard to clinical and radiological evaluations in lateral discoid meniscus tears, the full-extent single-leaf partial meniscectomy group had no adverse results compared with the total meniscectomy group and was not significantly different compared to the conventional partial meniscectomy group. Study designCohort study. Level of evidenceLevel III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence