Discoid Lateral Meniscus Research Articles

Evaluation of the knee joint morphology associated with a complete discoid lateral meniscus, as a function of skeletal maturity, using magnetic resonance imaging.

A discoid lateral meniscus (DLM) is associated with increased risk for meniscal tears and progression of knee joint osteoarthritis. Our aim was to differentiate knee joint morphology between patients with and without a DLM, as a function of skeletal maturity, using magnetic (MR) imaging. This was a retrospective analysis of MR images of the knee for 110 patients, 6-49years of age. Of these, 62 were in the open physis group (38 with a DLM) and 48 in the closed physis group (23 with a DLM). The following morphological parameters were measured: anterior obliquity of the lateral tibial plateau (AOLTP), posterior obliquity of the lateral tibial plateau (POLTP), the lowest point of the lateral femoral condyle (LPLFC), and the posterior lateral condylar angle (PLCA). Regardless of skeletal maturity, a DLM was associated with a greater inclination of the POLTP, lateralization of the LPLFC, and smaller PLCA (p < 0.001 for all compared to that of the control group). In the DLM group, the inclination of the AOLTP and the POLTP were significantly smaller (p < 0.001) and the LPLFC was more lateral (p < 0.001) in the closed physis group than in the open physis group. In the control group, the inclination of the POLTP was larger (p < 0.001) and the PLCA smaller (p = 0.019) in the open than in the closed physis group. We identified a characteristic knee morphology among patients with a complete DLM using MR imaging, which was observed before physeal closure and persisted after skeletal maturity was attained. We also noted lateralization of the LPLFC in the presence of a DLM, with an increase in lateralization with skeletal maturation. Case-control study, III.

Partial resection of lateral discoid meniscus changes lower limb axial alignment – A retrospective cohort study

AimThis study aimed to explore the changes in lower limb axial alignment and knee joint function after arthroscopic partial resection of the discoid lateral meniscus. MethodsPreoperative and postoperative full-length weight-bearing radiographs of the lower limb were obtained from a total of 161 patients with lateral menisci tears from September 2018 to September 2020 who underwent partial meniscal resection. The patients were divided into discoid meniscus group (DMG) and ordinary meniscus group (OMG). The measured mechanical axis deviation (MAD), proximal tibia angle (PTA), and distal femoral angle (DFA) in the axial alignment of the lower limb were determined before and after surgery. Knee joint function on the affected side was determined using the International Knee Documentation Committee (IKDC) subjective scale and the Lysholm knee scoring scale before surgery and at one, six, 12, and 24 months after surgery. ResultsFor MAD and DFA, there were statistically significant differences between the preoperative and postoperative findings within each group (P < 0.01); the MAD and DFA were smaller after surgery. The difference in preoperative and postoperative PTA of the DMG was statistically significant (P < 0.01), meaning that the PTA becomes larger after surgery. The differences in preoperative and postoperative PTA of the OMG, preoperative PTA between the two groups, and postoperative PTA between the two groups were not statistically significant (P > 0.05). Intragroup comparisons of the IKDC subjective scale and the Lysholm knee scoring scale before and after surgery revealed significant differences (P < 0.05). ConclusionArthroscopic partial resection of the discoid lateral meniscus is a safe and effective surgical method that can significantly improve knee joint function. Although the axial arrangement of the lower limbs will be slightly changed in the early stage, it will still be within the normal range after surgery in patients with normal lower limb axial alignment. For patients with varus or valgus before surgery, this procedure should be applied with caution.

Surgical Management of Discoid Lateral Meniscus With Anterior Peripheral Instability: Retaining an Adequate Residual Meniscus Volume

Discoid lateral meniscus (DLM) presents with differing pathoanatomy and may exhibit various types of tears. The treatment strategy is based on the presence and location of instability as a result of deficient capsular attachment. Recently, meniscal stabilization after saucerization has been recommended for DLM to preserve the meniscus shape, prevent extrusion, and mitigate against the progression of osteoarthritis. In addition to stabilization, the resection volume is important to prevent osteoarthritic changes. Although there was no tear and no displacement of the lateral meniscus on magnetic resonance imaging, some DLMs were found to have tears and peripheral instability during arthroscopy. Therefore, the assessment of peripheral instability during surgery is very important to achieve a desirable clinical outcome. This Technical Note describes an arthroscopic technique for anterior peripheral stabilization of the DLM, in which we highlight the surgical procedure for repair of the anterior horn, reassess the instability around the popliteal hiatus after the anterior horn is repaired, and the stabilization of the posterior horn, if necessary.

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

Plain Radiographs Have Limited Utility in the Evaluation of Discoid Lateral Meniscus

Background:Debate persists regarding which radiographic measurements are important when investigating a possible discoid lateral meniscus and the utility of x-rays in the diagnostic workup.Hypothesis/Purpose:The purpose of this study was to identify differences in various measurements between healthy knees and those with a discoid meniscus while controlling for other patient characteristics.Methods:Radiographs of patients with a confirmed discoid lateral meniscus were matched by age and sex to those with a healthy knee (verified by magnetic resonance imaging). The following parameters were associated with discoid meniscus in previous studies and were measured on x-ray for each subject: lateral joint space height (both in the central and medial portion of the compartment; LJSH-C and LJSH-M, respectively), medial joint space height, fibular head height (FHH), lateral tibial spine height, femoral inter-epicondylar distance, lateral tibial plateau obliquity, and chordal distance of the femoral condyle (medial and lateral). Ratios were calculated between LJSH-C/M and medial joint space height. Univariate analysis was followed by multivariate regression to adjust for confounders.Results:The study included 57 patients with a discoid meniscus and 55 controls with a mean age of 11.0±3.5 years (50% female). The median LJSH-C for subjects with a discoid meniscus was 7.3 mm [interquartile range (IQR) 2.1] compared to 5.8 mm (IQR 2.2) in normal knees (p<0.001). A similar difference was found for LJSH-M [6.9 mm (IQR 2.9) vs. 5.4 mm (IQR 2.4), p=0.002]. Mean FHH was lower for discoid menisci than controls (12.5±4.0 mm vs. 14.9±5.9 mm, p=0.01). No other radiographic measurements were significantly different between cases and controls. When adjusting for covariates in regression analysis, the presence of a discoid meniscus was predictive of a higher LJSH-C and LJSH-M and lower FHH. Of note, age and sex were also significantly predictive in these models. Patients with a discoid meniscus had 3.5 times higher odds of LJSH-C ≥7 mm [95% confidence interval (CI) 1.5-8.3, p=0.005), 3.3 times higher odds of LJSH-M ≥6 mm (95% CI 1.4-7.9, p=0.006), and 3.1 times higher odds of FHH <16 mm (95% CI 1.2-7.8, p=0.02).Conclusion:After controlling for other factors, LJSH-C, LJSCH-M, and FHH on plain radiographs were associated with a discoid lateral meniscus. However, many previously reported measurements were not predictive. While these parameters may aid diagnostic decision making when there is suspicion for a discoid meniscus, age and sex must also be considered. Advanced imaging may be required to confirm the diagnosis.

Clinical Features and Operative Treatments of Discoid Medial Meniscus in Children

Background:The discoid medial meniscus is a rare congenital anomaly of the knee. The literature on discoid medial menisci is limited, with few reported cases in children.Purpose:To report the clinical manifestations and operative treatments of discoid medial menisci in children from multiple centers in North America.Methods:A retrospective review of medical records including operative reports was performed to identify patients diagnosed with a discoid medial meniscus confirmed via direct surgical observation across eight children’s hospitals between January 2000 and March 2020.Results:Twenty-one patients (9 female, 12 male) with 22 discoid medial menisci were identified, one with bilateral discoid medial menisci. The mean age at time of diagnosis was 12.7 years (range, 3-18 years). One patient had discoid medial and discoid lateral menisci in the same knee. The most common symptoms and signs of patients with a discoid medial meniscus were locking and/or clunking, present in over 50% of patients. Twelve discoid medial menisci were complete (55%), 8 were incomplete (36%), and two were indeterminate (9%). Tears were present in 13 knees. Of those with tears, 7 were horizontal tears (4 posterior, 1 anterior, and 2 mid-body), 5 were complex (3 posterior, 1 anterior, and 1 mid-body), and 1 was a posterior vertical tear. Five of these discoid medial menisci were unstable (23%). The average time between initial diagnosis and treatment was 13 months (range, 0-121 months). All knees underwent arthroscopic saucerization, and of the 13 torn discoid medial menisci, 7 were repaired (54%). The mean length of clinical follow-up postoperatively was 24 months (range, 1-82 months). Four of these discoid medial menisci underwent re-operation, most commonly for persistent symptoms. All knees which required re-treatment initially presented with a tear, all of which had been repaired. There was a significant association between initial presence of a tear and need for re-operation, [χ2 = 4.1, p = 0.044].Conclusions:In this multicenter study of patients treated for a discoid medial meniscus, symptoms and signs at presentation and findings at arthroscopy were similar with those commonly seen in patients with a discoid lateral meniscus. Tears were present in more than half of knees, and reoperation was more common in knees identified with tears of their discoid medial menisci than those without tears. Future studies should seek to determine the long-term functional and patient-reported outcomes following treatment of discoid medial menisci.

Reliability of Magnetic Resonance Imaging Interpretation of Lateral Discoid Meniscus: A Multicenter Study

Background:Lateral discoid meniscus (LDM) often present with complex morphology that can be challenging to assess and treat arthroscopically. Preoperative magnetic resonance imaging (MRI) is frequently used for diagnosis and surgical planning, however it is not known whether surgeons are reliable and consistent in their interpretation of MRI findings.Hypothesis/Purpose:We hypothesize that surgeons experienced in treating LDM are able to reliably interpret discoid pathology using MRI, with the exception of evaluating dynamic factors (i.e. instability).Methods:Forty five discoid meniscus MRI selected from a pool of surgical discoid meniscus cases were included in this review. Five reviewers (experienced pediatric sports medicine surgeons) who were not involved in the MRI selection process performed independent review of each MRI to determine discoid meniscus classification. More than 4 weeks later, a second reading was performed by 3 of the 5 reviewers. Interobserver and intraobserver reliability of the primary (width, presence of instability or tear) and secondary (location of instability or tear, tear type) rating factors was assessed using the Fleiss κ coefficient, designed for multiple readers with nominal variables (reliability: fair, 0.21–0.40; moderate, 0.41–0.60; substantial, 0.61–0.80; excellent, 0.81–1.00). Reliability is reported as κ (95% CI).Results:Interobserver reliability of assessment of meniscal width was substantial 0.67 (0.58-0.76), and intraobserver was moderate 0.52 (0.35-0.69). Assessment of presence of peripheral instability had moderate interobserver reliability 0.54 (0.45-0.63) and substantial intraobserver 0.61 (0.44-0.78). Presence of tear had fair interobserver reliability 0.39 (0.29–0.48) and substantial intraobserver 0.68 (0.51-0.85). When identifying location of instability or tear, interobserver reliability was moderate while intraobserver agreement was substantial for assessment of anterior instability (0.47 (0.37-0.56) and 0.68 (0.51-0.85), respectively); posterior instability (0.56 (0.47-0.65) and 0.62 (0.45-0.79), respectively); and posterior tear (0.41 (0.32-0.50) and 0.69 (0.52-0.86), respectively). The exception was identifying anterior tear, with fair interobserver reliability 0.33 (0.23-0.42) and moderate intraobserver 0.56 (0.39-0.73); Interobserver reliability was fair for tear type 0.34 (0.28-0.41) and intraobserver reliability moderate 0.55 (0.43-0.67).Conclusion:Orthopaedic surgeons experienced in the treatment of LDM vary from each other in their classification using MRI, especially with regard to assessment of meniscus tears. MRI evaluation may be helpful to diagnose discoid by width and identify presence of instability, two major factors in the decision to proceed with surgery. However, definitive treatment should be guided by a comprehensive arthroscopic evaluation.

Higher Rates of Mensical Repair and Rim Preservation in Younger Patients with Discoid Lateral Menisci

Background:Management of discoid meniscus in pediatric patients requires understanding of the presentation, associated risks, and appropriate techniques. Surgical treatment consists of saucerization, meniscus repair, meniscocapular stabilization, and, periodically, subtotal meniscectomy. The type of meniscal treatment is commonly determined during arthroscopy. Thus, surgeons, patients, and their parents/guardians must be prepared for a variety of surgical options.Hypothesis/Purpose:To compare intraoperative arthroscopic findings and treatment of discoid meniscus across pediatric age groups in a large multicenter quality improvement registry.Methods:A multi-center quality improvement registry (16 institutions, 26 surgeons) monitoring the safety of discoid meniscus surgery was reviewed. Audit processes using CPT codes were designed to ensure that all consecutive cases from 2018-2020 were prospectively entered on patients <19 years old into a HIPAA-compliant electronic platform. Patients were grouped into five groups based on age at time of surgery (<7, 7-10, 11-13, 14-16, >16). Demographic characteristics, discoid type, presence and type of tear, peripheral rim instability, repair technique, and partial meniscectomy/debridement beyond saucerization were reviewed. Chi-Square or Fisher’s exact tests were used for categorical comparisons and a Kruskal-Wallis test for continuous comparisons.Results:274 patients were identified (mean age 12.4 years, range 3-18; 47.3% females). Complete discoid meniscus and peripheral rim instability were found to be more prevalent in younger age groups (Table 1). Peripheral rim instability was noted in 55.5% of cases, most commonly in the posterior horn (24.8%). While a focal region of instability was most common, the youngest age group was more likely to have either multifocal instability or no instability. Repair was conducted more commonly in the younger cohorts, with a significant decrease in repair percentage (p=0.008) per age group. All-inside was the most common repair technique in all age groups. Partial meniscectomy/debridement beyond saucerization occurred more frequently in older age groups than younger age groups (p=.0002), including 38.4% of cases in the oldest age group (Table 2).Conclusion:Younger patients experienced a greater incidence of complete discoid menisci and meniscus repair in this age group and was more likely to have more than one area of rim instability. However, when meniscal resection beyond a saucerization was required, this was more likely to occur in older patients.Table 1.Age-Related Comparison of Discoid Meniscal Presentation and TreatmentTable 2.Incidence of Additional Meniscal Resection Beyond Saucerization

Association of Postoperative Lateral Meniscal Extrusion With Cartilage Degeneration on Magnetic Resonance Imaging After Discoid Lateral Meniscus Reshaping Surgery.

Background:Although arthroscopic reshaping surgery for a discoid lateral meniscus (DLM) has good clinical results, it cannot completely prevent degeneration. The degree of DLM extrusion associated with degenerative changes is unclear.Purpose/Hypothesis:To measure meniscal extrusion preoperatively and postoperatively in patients who underwent DLM-reshaping surgery and examine factors associated with knee articular cartilage degeneration. It was hypothesized that meniscal extrusion existed preoperatively, progressed postoperatively, and was related to knee joint degeneration.Study Design:Case-control study; Level of evidence, 3.Methods:We retrospectively reviewed the medical records of patients who underwent DLM-reshaping surgery and attended ≥2 years of follow-up. Magnetic resonance imaging (MRI) was performed preoperatively and at 24 months postoperatively, and residual midbody meniscal extrusion was measured. Cartilage degeneration was detected when the Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the lateral compartment was grade ≥3 at 2 years postoperatively. Factors associated with MRI cartilage degeneration were evaluated.Results:Included in this study were 48 knees in 39 patients; the mean patient age at the time of surgery was 12.0 years. The mean midbody meniscal extrusion significantly increased from 0.8 mm preoperatively to 1.6 mm at 24 months postoperatively (P < .001). According to the WORMS cartilage score, 16 patients were categorized as having MRI cartilage degeneration. Multivariate logistic analysis showed that an inferior preoperative Lysholm score (odds ratio, 0.89; P = .024) and postoperative extrusion (odds ratio, 6.18; P = .010) significantly increased the risk of cartilage degeneration. The receiver operating characteristic curve showed that a residual meniscal extrusion of 2.0 mm was the cutoff value indicating cartilage degeneration (sensitivity, 87.5%; specificity, 78.1%).Conclusion:DLM extrusion significantly increased from 0.8 mm preoperatively to 1.6 mm at 2 years postoperatively. Postoperative extrusion and a lower preoperative Lysholm score were factors related to MRI cartilage degeneration postoperatively. A postoperative extrusion of 2.0 mm was the cutoff value for MRI cartilage degeneration.

Long-Term Minimum 15-Year Follow Up After Lateral Discoid Meniscal Preservation Surgery in Children and Adolescents

Background:Discoid meniscus is a congenital variant typically affecting the lateral meniscus of the knee. Historically, surgical intervention when symptomatic consisted of total meniscectomy; however, after degenerative changes were observed, current treatments now focus on rim preservation with arthroscopic saucerization and meniscal repair for instability, when indicated.Purpose:The aim of this study was to examine long-term patient-reported outcomes of lateral discoid menisci (LDM) treated with meniscal-preserving techniques.Methods:Ninety-eight patients treated arthroscopically for LDM at a single institution at a minimum of 15 years ago were retrospectively identified and contacted by mailers and telephone to participate. Subjective functional outcomes and patient satisfaction data were collected using a questionnaire that included the validated IKDC Subjective Knee Evaluation Form, Lysholm Score, Marx Activity Rating Scale, Tegner Activity Score, and WOMAC Osteoarthritis Index. Patient and surgical characteristics and patient-reported outcomes were summarized by mean and standard deviation (SD), median and interquartile range (IQR), or frequency and percent, as appropriate.Results:Of the 46 patients contacted (response rate of 46/98 eligible), 25 (54%) completed the questionnaires. The mean (± SD) age at initial surgery was 10.8 (± 3.4) years and 30.3 (± 3.7) years at final follow-up. The mean (± SD) follow-up time from initial surgery was 19.5 (± 2.8) years (range, 16–27). Patient-reported outcomes included: IKDC 77.4 ± 17.2, Lysholm 78.6 ± 21, WOMAC 7.6 ± 11.3, Tegner Activity 7 (out of 10), and Marx Activity Rating Scale 8 (out of 10) (Table 1). Eleven (44%) cases underwent subsequent LDM-related surgery on the ipsilateral knee(s). There were no cases of total knee replacement (Table 2).Conclusions:Overall, patient-reported outcomes were favorable at a minimum of 15-year follow-up after rim-preserving saucerization of lateral discoid meniscus. While two-thirds of patients were satisfied with their surgical outcomes, nearly half of patients underwent revision saucerization with or without meniscal repair. Subsequent long-term follow-up studies with radiographs will be important to determine how meniscus-preserving procedures may curb the development of arthritis.Table 1.Overall Postoperative Outcomes (N=25 patients)a Table 2.Postoperative Outcomes by Discoid Type and Surgery (N=26)a

Evaluation of morphological characteristics for incomplete discoid medial meniscus with an oversized posterior segment

BackgroundA discoid medial meniscus is rare in comparison with a discoid lateral meniscus. We encountered a new type of incomplete discoid with an oversized posterior segment. Therefore, this study aimed to report cases of medial meniscus with an oversized posterior segment and analyze the morphological characteristics by comparing them to cases with a discoid medial meniscus and normal medial meniscus.MethodsFour patients with an oversized posterior segment medial meniscus (oversize group, mean age: 25.3 ± 12.0 years) and seven patients with a discoid medial meniscus (discoid group, mean age: 34.4 ± 19.6) were identified using magnetic resonance imaging (MRI) and diagnosed by arthroscopic findings in our hospital. Fifty patients without medial meniscal injury were retrospectively selected as the normal group (normal group, mean age: 24.0 ± 11.3 years). The clinical symptoms were examined. The anteroposterior (AP) length of both the anterior and posterior segments, AP length ratio of the posterior segment to the AP length of the medial tibial plateau, and mediolateral (ML) width of the mid-body of the medial meniscus were also evaluated using MRI and compared among the three groups.ResultsAll patients in the oversize group complained of medial knee pain during deep knee flexion. In sagittal MRI, posteriorly deviated indentations were also observed at the medial tibial plateau in all cases in the oversize group. There was a significant difference in the AP length of the posterior segment between the normal and oversize groups (14.3 ± 2.8 vs. 23.6 ± 2.8 mm, P < 0.001), whereas there was no significant difference in the AP length of the anterior segment (9.1 ± 2.1 vs. 9.5 ± 1.9 mm, P = 0.869). The ML width of the mid-body in the normal, oversize, and discoid groups was 9.3 ± 1.8, 19.9 ± 2.6, and 25.8 ± 1.9 mm, respectively (normal vs. oversize group: P < 0.001, oversize vs discoid group: P = 0.01, normal vs. discoid group: P < 0.001).ConclusionsOversized posterior and normal anterior segments characterize this new type of incomplete discoid medial meniscus as a morphological abnormality.

A narrative review of lateral meniscus root tears and extrusion: techniques and outcomes.

In this review, we performed a literature search and described the surgical procedure for a lateral meniscus posterior root tears (LMPRT) repair using a pull-out technique and an arthroscopic centralization for lateral meniscus (LM) extrusion. The menisci play a pivotal role in the shock-absorbing and load-dispersing functions of the knee joint. They also contribute to its stability. Meniscal root tears substantially affect meniscal hoop function and accelerate cartilage degeneration. Additionally, LMPRT have been shown to affect anterolateral knee laxity and tibiofemoral contact pressure in knees with anterior cruciate ligament (ACL) injury. Therefore, appropriate management of LMPRT is essential for restoring knee function. Meniscus extrusion has attracted attention due to its association with early osteoarthritis (OA). Recently, an arthroscopic centralization technique has been proposed to reduce meniscal extrusion. During this procedure the capsule attached to the meniscus is sutured to the edge of the tibial plateau using suture anchors. A narrative review of LMPRT repair and arthroscopic centralization of lateral meniscal extrusion was performed through a PubMed search. Specific magnetic resonance imaging (MRI) signs were useful for the diagnosis of LMPRT. Pull-out techniques can restore knee stability and load distribution function and result in favorable clinical outcomes. Arthroscopic centralization of the extruded LM caused by meniscectomy and lateral discoid meniscus achieved satisfactory clinical outcomes at the 2-year follow-up. Biomechanical studies demonstrated that this procedure reduced meniscus extrusion and had beneficial effects on load distribution and joint stability. In summary, to restore knee function, LMPRT should be repaired as much as possible. The centralization technique is a promising surgical treatment for extruded lateral menisci due to meniscectomy and discoid meniscus. However, due to the lack of high-level evidence studies such as randomized control trials (RCTs) in this field, it remains necessary to accumulate evidence to confirm the efficacy of LMPRT repair and the centralization technique.

Comparison of the Healing Outcomes of Conservative Treatment for Stable Juvenile Osteochondritis Dissecans of the Lateral Femoral Condyle With Normal Lateral Meniscus and Incomplete Discoid Lateral Meniscus.

This study aimed to compare the healing outcomes of conservative treatment for osteochondritis dissecans (OCD) of the lateral femoral condyle with normal lateral meniscus and incomplete discoid lateral meniscus (DLM). Forty-four knees in 37 juvenile patients (mean age 9.9 y) with stable OCD and whose lateral meniscus shape was normal or incomplete DLM were enrolled. All patients underwent conservative treatment with physical activities prohibited. For each lateral meniscus group, patient demographics including pretreatment Tegner activity scale, OCD stage, and Lysholm score, radiographic healing status; complete or incomplete healing at 3 months, 6 months, and 1 year, time to complete healing and post-treatment clinical scores were evaluated. There were 21 (47.8%) and 23 (52.3%) knees with normal menisci and incomplete DLM, respectively. At 3 months, 6 months, and 1 year after conservative treatment, healed OCD status was noted in 3 (14.3%), 12 (57.1%), and 19 (90.5%) knees of the normal type and in 3 (13.0%), 12 (52.2%), and 20 (86.9%) knees of the incomplete DLM type, respectively (P>0.05). The mean time to healing in each group was 198 and 181 days, respectively. No significant differences in terms of OCD healing rate at each time, time to healing, and post-treatment clinical scores were found between the groups. No significant differences in the OCD healing rate or time to healing were found between the normal and incomplete DLM type. Therefore, treatment strategy for OCD with stable and asymptomatic incomplete DLM should be the same as that for those occurring with a normal meniscus.

Diagnostic value of ultrasound in the discoid lateral meniscus of the knee

Based on the anatomical differences between discoid lateral meniscus(DLM) and normal lateral meniscus (NLM), this study aims to setting up the ultrasound examination parameters to distinguish DLM and NLM and explore the diagnostic value of these parameters on DLM. According to the inclusion, exclusion and matching criteria, 66 DLM patients(DLM group) and 132 NLM patients with other knee joint diseases(NLM group), hospitalized from October 2019 to June 2020, were included in this study. There were 18 males and 48 females in the DLM group, ranging in age from 3 to 60 years old, with a mean of (36.9±12.1) years old;36 males and 96 females in the NLM group, ranging in age from 3 to 60 years old, with a mean of (40.0±12.2) years old. Philips high frequency(3.0 to 12.0 MHz) linear array ultrasound probe was used to examine the lateral meniscus of all patients in two groups. Nine parameters including the thickness, width and the included angle of the anterior angle, body and posterior angle respectively in the lateral meniscus were measured. The included angke is formed by the chords of the upper and lower curved surfaces of the meniscus at the free edge. The independent t test was used to analyze the difference of the measured parameters between the DLM group and the NLM group. The receiver operating characteristic(ROC) curve was used to evaluate the cut-off value of each parameter for diagnosing DLM and the corresponding sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve(AUC). The above 9 ultrasound measurement parameters between the DLM group and the NLM group had significant statistical differences(P<0.001). The ROC curve analysis method evaluated the cut-off value and diagnostic capabilities of these nine ultrasound parameters for DLM. The results showed that the cut-off value of the included angle of anterior part, body and posterior part were 25.85°, 24.85° and 29.15 °, respectively;and the sensitivity, specificity, negative predictive value, positive predictive value and AUC were significantly higher than other parameters, which were 88%, 91%, 79%, 95%, 0.94;89%, 94%, 82%, 97%, 0.96; 92%, 97%, 86%, 98%, 0.97, respectively. Ultrasound diagnosis of DLM is feasible and reliable. The diagnostic ability of the included angle of the anterior part, body and posterior part in the lateral meniscus measured by ultrasound to diagnose DLM are significantly better than other ultrasound measurement parameters, and the sensitivity and specificity of those parameters are close to MRI. Therefore, ultrasound can be used as a reliable method for preliminary diagnosis of DLM.

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.

Single-cell RNA sequencing reveals the cell types heterogenicity of human discoid lateral meniscuscells.

Discoid lateral meniscus (DLM) is more prone to injury than a normally shaped meniscus. No study has compared the gene expression and cell heterogeneity between discoid and normal menisci. We aimed to identify specific cell clusters and their marker genes in discoid meniscus, thereby providing a theoretical basis for the treatment and etiology of DLM. ScRNA-seq was used in DLM and osteoarthritis lateral meniscus (OAM) cells to identify cell subsets and their gene signatures. Pseudo-time analysis and immunohistochemical staining were used to investigate the temporal and spatial distribution of DLM-specific clusters. ScRNA-seq identified nine clusters originating from DLM and OAM, composed of seven empirically defined populations and two novel populations specific to DLM, namely, the prehypertrophic chondrocyte 2 (PreHTC-2) and regulatory chondrocyte (RegC-2) populations. Single-cell trajectory showed that RegC-2 and PreHTC-2 were mainly distributed in a specific cell fate, with the PreHTC-2 marker gene HAPLN1 highly expressed at the end of this fate. Immunohistochemical staining showed that HAPLN1 + cells were mainly distributed in the white zone of DLM. Matrix metalloproteinase (MMP) variants were expressed in DLM and OAM, with MMP2 highly expressed in OAM-dominant cell clusters, while MMP3 was highly expressed in DLM-dominant cell clusters. We concluded that two novel cell clusters including PreHTC-2 were identified using single-cell sequencing, which were mainly distributed in the white areas of DLM. Differentiated MMP expression in the trajectory may be a possible mechanism of DLM formation.

Physical Therapy Following Saucerisation of Discoid Meniscus – a Case Study

Introduction: Discoid meniscus is a structure with altered shape, which causes it to frequently undergo injuries and lesions. Pain, limping, limited range of motion of the knee joint and swelling are characteristic signs of this pathology. Therapeutic possibilities include meniscectomy and saucerisation. Research objective: The study aim was assessment of the therapeutic effectiveness in a patient after saucerisation of discoid meniscus. Material and methods: A 12-year-old female patient after saucerisation of lower left limb lateral discoid meniscus (type I) was subjected to 32-week physical therapy treatment. Testing included determining the range of knee joint flexion and extension movements, as well as measuring the circumference of the lower extremities 15 cm above the patella. The Kujala Score (Anterior Knee Pain Scale) and Ikeuchi grading system were employed during the 1st, 3rd, 8th, 21st and 32nd weeks postoperatively. Results: In the final stage of physical therapy, complete range of knee joint motion was achieved, the Kujala Scale score totalled 98 points and the thigh circumference of the operated limb increased by 4 cm. The circumferences of the lower extremities differed by 2 cm in the final phase of physical therapy. Conclusions: The employed postoperative protocol effectively influenced the functional state of the patient.

T2 Relaxation Time Changes in the Distal Femoral Condylar Cartilage of Children and Young Adults with Discoid Meniscus.

ObjectiveTo investigate compositional changes in the distal femoral condylar cartilage (FCC) of children and young adults with and without discoid meniscus by T2 relaxation time mapping.DesignWe retrospectively reviewed knee magnetic resonance images including sagittal T2 maps of distal FCC performed in patients with or without discoid meniscus. Combined meniscal pathology such as degeneration or tears was also reviewed. Regions of interest were selected, and T2 relaxation time profiles were generated according to medial and lateral and FCC and according to weight-bearing and non-weight-bearing FCC. Nonparametric comparison tests using median values were performed.ResultsSeventy-nine knees from 73 patients (2-20 years) including 45 knees with lateral discoid meniscus (discoid group) were studied. T2 values of FCC showed negative correlation with age in both the discoid and nondiscoid groups (P < 0.01), except for medial weight-bearing FCC. In the discoid group, T2 relaxation times of lateral weight-bearing FCC (median, 46.5 ms) were lower than those of lateral non-weight-bearing (median, 53.2 ms; P < 0.001) and medial weight-bearing (median, 50.5 ms; P = 0.012) FCC. Lateral weight-bearing FCC also showed lower T2 values than other areas in patients with meniscal pathology in the discoid group. However, T2 relaxation times did not differ between the discoid and nondiscoid groups in patients without meniscal pathology.ConclusionsChildren and young adults with discoid meniscus have lower T2 relaxation times in lateral weight-bearing FCC compared with non-weight-bearing or medial FCC, suggesting compositional changes have occurred in these patients.

Morphological change and its associating factors in the residual meniscus after arthroscopic reshaping surgery for a discoid lateral meniscus

Morphological change and its associating factors in the residual meniscus after arthroscopic reshaping surgery for a discoid lateral meniscus

Risk factors for the postoperative effect of symptomatic discoid lateral meniscus after arthroscopy

To explore the influencing factors of the postoperative effect of arthroscopic treatment of symptomatic discoid lateral meniscus (DLM). From September 2008 to September 2015, patients with symptomatic DLM treated by arthroscopic surgery were retrospectively analyzed. The knee function was evaluated by Lysholm scoring system. According to the scoring results, it was divided into excellent (≥90 points), good (80 to 89 points), fair (70 to 79 points) and poor (<70 points). Sixteen research factors were collected, namely gender, operation age, body mass index, work intensity, symptom duration, history of knee injury, involved knee side, DLM classification, DLM injury type, DLM injury site, medial meniscus injury, knee cartilage injury site and degree, Kellgren-Lawrence (K-L) classification, operation method, and latest follow-up time. According to the data type, Kruskall-Wallis rank sum test or χ2 test was used for univariate analysis, and ordinal Logistic regression model was used for multivariate analysis. Univariate analysis showed that the statistically significant factors were included in the multivariate analysis model, and the independent risk factors influencing the curative effect of symptomatic DLM were obtained. According to the inclusion and exclusion criteria, 502 patients were included. Lysholm functional grade at the latest follow-up was higher than that before operation (P<0.001). Univariate analysis showed that there were significant differences in gender, body mass index, work intensity, history of knee injury, age of operation, duration of symptoms, medial meniscus injury, K-L grade, operation method, location and degree of knee cartilage injury among Lysholm functional grades(P<0.05). Ordinal logistic regression analysis showed that female was an independent risk factor for postoperative efficacy (P=0.002, OR=0.370);body mass index (P=0.007, OR=0.894), work intensity(P=0.004, OR=0.525), age of operation(P<0.001, OR=0.953), duration of symptoms(P<0.001, OR=0.989), degree of cartilage damage (P=0.016, OR=0.631) were negatively correlated with Lysholm knee function classification. Arthroscopy is a safe and effective method for the treatment of symptomatic DLM. The gender, body mass index, work intensity, age of operation, duration of symptoms and degree of knee cartilage injury are independent influencing factors for the postoperative efficacy of symptomatic DLM.