Incomplete Discoid Lateral Meniscus Research Articles

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.

Symptomatic discoid lateral meniscus shows a relationship between types and tear patterns, and between causes of clinical symptom onset and the age distribution

Discoid meniscus is a congenital abnormality of the lateral meniscus and is seen more frequently in East Asia. The purpose of this study was to retrospectively assess the relationship between discoid lateral meniscus (DLM) types and tear patterns and causes of age-specific clinical symptom onset. Of 1650 arthroscopic surgeries over a 20-year period, 138 (105 patients) were performed for DLM and were evaluated in this study. The mean age at surgery was 21.5 ± 15.8years. The DLM type was classified by Watanabe's classification, and tear patterns were classified by the modified Bin's classification as simple horizontal, complicated horizontal, longitudinal, radial, complex, and no tear. Additionally, patients were divided by age group (< 10, 10-19, 20-39, 40-59, and ≥ 60years) and classified according to the causes of clinical symptom onset as follows: sports activities, minor trauma in daily living, and no traumatic episode. The DLM was complete in 78 (56.5%) knees and incomplete in 60 (43.5%); no Wrisberg type DLM was observed. Simple horizontal and complicated horizontal tears were significantly more frequent in complete DLM, whereas radial tears and no tears were significantly more frequent in incomplete DLM (p < 0.0001). When classified by age group, 74 (53.6%) knees with DLMs were found in teenagers. Sports activities caused symptom onset significantly more often in teenagers, no traumatic episode caused symptom onset in patients aged < 10years, and minor trauma in daily living caused symptom onset in patients aged 40-59years and ≥ 60years (p < 0.0001). No relationship was found between the age distribution and tear patterns; however, the absence of tears tended to be more common in teenaged patients, and complicated horizontal tears were more common in patients over 20years of age. Symptomatic DLM occurred most often in teenagers. A relationship was identified between the DLM types and tear patterns, which could be helpful in preoperative planning. Causes of clinical symptom onset in patients with DLM were characterised by age group, which might help clinicians to suspect the presence of DLM. Level IV.

Facteurs radiologiques et IRM de bilatéralité devant une lésion symptomatique sur ménisque discoïde latéral

BackgroundThe incidence of bilateral discoid lateral meniscus (DLM) is as high as 73 to 85%, and associated contralateral meniscus tears ranged from 4 to 33% in symptomatic surgical DLM. The goal of the study was analyzing the factors that predict contralateral presence and tearing of DLM in patients who underwent surgery for symptomatic DLM. Our hypothesis was that there is a significant correlation between operative DLM properties and the incidence of bilateral DLM with associated contralateral meniscus tears. These properties include tear patterns, younger patient age, and characteristic X-ray findings. Patients and methodsThis prospective study included 76 patients who underwent arthroscopic surgery for symptomatic DLM. The contralateral knees were evaluated with X-ray and MRI. Based on the MRI findings, DLM was categorized into three types, and tear patterns were analyzed. The characteristic X-ray findings were evaluated as follows: (1) high fibular head, (2) squared-off appearance of the lateral femoral condyle, (3) cupping of the lateral tibial plateau, (4) widened femorotibial joint space, (5) hypoplasia of the lateral intercondylar spine, (6) notching of the LFC. The number of characteristic X-ray findings (0/1/more than 2) was noted. Binary logistic analysis was performed to find the factors that predict the presence and tear of contralateral DLM. ResultsMRI of contralateral knees revealed 43 cases (57%) of complete DLM, 25 cases (33%) of incomplete DLM, and 8 cases (11%) of normal meniscus. Meniscus tears were found in 29 cases (38%) in the contralateral knee. X-ray of the contralateral knee revealed that 27 patients (36%) had one and 24 patients (32%) had two or more characteristic X-ray findings. On logistic regression analysis, the associations between contralateral knee meniscal tear and the presence of one or more than two characteristic X-ray findings were statistically significant (OR: 16.5, p=0.028; OR: 264.0, p=0.000, respectively). DiscussionThe number of characteristic X-ray findings in the contralateral knee is a significant predictive factor for contralateral DLM type and/or tear. Symptomatic DLM patients with characteristic X-ray findings should be carefully evaluated for contralateral DLM and meniscal tears. Level of evidenceIII, prospective diagnostic study of consecutive patients.

Factors associated with bilateral discoid lateral meniscus tear in patients with symptomatic discoid lateral meniscus tear using MRI and X-ray

BackgroundThe incidence of bilateral discoid lateral meniscus (DLM) is as high as 73 to 85%, and associated contralateral meniscus tears ranged from 4 to 33% in symptomatic surgical DLM. The goal of the study was analyzing the factors that predict contralateral presence and tearing of DLM in patients who underwent surgery for symptomatic DLM. Our hypothesis was that there is a significant correlation between operative DLM properties and the incidence of bilateral DLM with associated contralateral meniscus tears. These properties include tear patterns, younger patient age, and characteristic X-ray findings. Patients and MethodsThis prospective study included 76 patients who underwent arthroscopic surgery for symptomatic DLM. The contralateral knees were evaluated with X-ray and MRI. Based on the MRI findings, DLM was categorized into three types, and tear patterns were analyzed. The characteristic X-ray findings were evaluated as follows: (1) high fibular head, (2) squared-off appearance of the lateral femoral condyle, (3) cupping of the lateral tibial plateau, (4) widened femorotibial joint space, (5) hypoplasia of the lateral intercondylar spine, (6) notching of the LFC. The number of characteristic X-ray findings (0/1/more than 2) was noted. Binary logistic analysis was performed to find the factors that predict the presence and tear of contralateral DLM. ResultsMRI of contralateral knees revealed 43 cases (57%) of complete DLM, 25 cases (33%) of incomplete DLM, and 8 cases (11%) of normal meniscus. Meniscus tears were found in 29 cases (38%) in the contralateral knee. X-ray of the contralateral knee revealed that 27 patients (36%) had one and 24 patients (32%) had two or more characteristic X-ray findings. On logistic regression analysis, the associations between contralateral knee meniscal tear and the presence of one or more than two characteristic X-ray findings were statistically significant (OR: 16.5, p=0.028; OR: 264.0, p=0.000, respectively). DiscussionThe number of characteristic X-ray findings in the contralateral knee is a significant predictive factor for contralateral DLM type and/or tear. Symptomatic DLM patients with characteristic X-ray findings should be carefully evaluated for contralateral DLM and meniscal tears. Level of evidenceIII, prospective diagnostic study of consecutive patients.

En guise d’introduction…

The incidence of bilateral discoid lateral meniscus (DLM) is as high as 73 to 85%, and associated contralateral meniscus tears ranged from 4 to 33% in symptomatic surgical DLM. The goal of the study was analyzing the factors that predict contralateral presence and tearing of DLM in patients who underwent surgery for symptomatic DLM. Our hypothesis was that there is a significant correlation between operative DLM properties and the incidence of bilateral DLM with associated contralateral meniscus tears. These properties include tear patterns, younger patient age, and characteristic X-ray findings.This prospective study included 76 patients who underwent arthroscopic surgery for symptomatic DLM. The contralateral knees were evaluated with X-ray and MRI. Based on the MRI findings, DLM was categorized into three types, and tear patterns were analyzed. The characteristic X-ray findings were evaluated as follows: (1) high fibular head, (2) squared-off appearance of the lateral femoral condyle, (3) cupping of the lateral tibial plateau, (4) widened femorotibial joint space, (5) hypoplasia of the lateral intercondylar spine, (6) notching of the LFC. The number of characteristic X-ray findings (0/1/more than 2) was noted. Binary logistic analysis was performed to find the factors that predict the presence and tear of contralateral DLM.MRI of contralateral knees revealed 43 cases (57%) of complete DLM, 25 cases (33%) of incomplete DLM, and 8 cases (11%) of normal meniscus. Meniscus tears were found in 29 cases (38%) in the contralateral knee. X-ray of the contralateral knee revealed that 27 patients (36%) had one and 24 patients (32%) had two or more characteristic X-ray findings. On logistic regression analysis, the associations between contralateral knee meniscal tear and the presence of one or more than two characteristic X-ray findings were statistically significant (OR: 16.5, p = 0.028; OR: 264.0, p = 0.000, respectively).The number of characteristic X-ray findings in the contralateral knee is a significant predictive factor for contralateral DLM type and/or tear. Symptomatic DLM patients with characteristic X-ray findings should be carefully evaluated for contralateral DLM and meniscal tears.III, prospective diagnostic study of consecutive patients.

Knee Pain - Exercise

HISTORY: A 58-year-old male presented with a 4-week history of spontaneous knee pain. One year prior to presentation, he had bariatric surgery and increased his exercise regimen resulting in a 100 lb weight loss. He denies trauma or inciting injury. His pain localized to the posterolateral knee and is described as a 5/10 cramping pain. He describes a popping sensation and experiences a snapping moment in the lateral knee with deep squatting. He denies swelling and ecchymosis. He has tried ice, physical therapy and ibuprofen without relief. PHYSICAL EXAMINATION: Focused left knee exam revealed a palpable cystic structure in the lateral popliteal fossa. There is tenderness over the lateral joint line with no instability of the proximal tibiofibular joint or biceps femoris tendon. Range of motion was 0-140° with pain greater than 120° of flexion. When the knee is brought into deep flexion, there is an audible pop over the lateral aspect of the knee. When the knee is then brought into extension, there is reproduction of an audible pop and snapping moment of the lateral knee at end range extension. Flexion McMurray’s test is positive. Strength, reflexes, sensation, and pulses are normal throughout. DIFFERENTIAL DIAGNOSIS: 1. Snapping biceps femoris tendon 2. Snapping popliteus tendon 3. Lateral meniscus tear 4. Iliotibial band friction syndrome 5. Proximal tibiofibular joint instability TEST AND RESULTS: Three view x-rays of left knee: • Medial joint space narrowing. No acute fracture. Dynamic ultrasound of the left knee: • Normal biceps femoris tendon. Popliteal cyst noted. MRI of left knee without contrast: – Incomplete discoid lateral meniscus and small multiseptated popliteal cyst noted. FINAL WORKING DIAGNOSIS: Left knee discoid lateral meniscus with subluxation of the meniscus TREATMENT AND OUTCOMES: 1. Patient counseled on activity modification. 2. Dynamic ultrasound revealed no evidence of hamstring irregularities. 3. Unsuccessful ultrasound-guided aspiration of popliteal cyst attempted followed by an intra-articular corticosteroid injection. 4. After MRI evaluation, orthopedic surgery performed an arthroscopic partial meniscectomy of subluxing torn posterior horn and midbody saucerization of lateral meniscus. 5. He tolerated surgery well with no further subluxation of his meniscus in physical therapy.

Histological and biological comparisons between complete and incomplete discoid lateral meniscus

ABSTRACTThe discoid lateral meniscus (DLM) is an anatomically abnormal meniscus that covers a greater area of the tibial plateau than the normal meniscus. The DLM is classified into two types: complete (CDLM) and incomplete (ICDLM) types. In this study, we investigated the histological and cell biological characteristics of CDLM and ICDLM. The number of blood vessels, proteoglycan deposition, and collagen distribution were assessed using meniscal tissues. Collagen production was also investigated in CDLM and ICDLM cells. The intercondylar region of the CDLM had a higher number of blood vessels than the inner region of the ICDLM. Safranin O staining density and type II collagen deposition in ICDLM were higher than those in CDLM. Type II collagen-positive cells were higher in ICLDM than in CDLM. CDLM cells showed slender fibroblastic morphology, while ICDLM cells were triangular chondrocytic in shape. This study demonstrated that the intercondylar region of the CDLM showed similar properties to the outer region of the meniscus. The inner region of the ICDLM, on the other hand, differed from the intercondylar region of the CDLM. Our results suggest that the intercondylar region of the CDLM may have a high healing potential like the outer meniscus.

Radiographic evaluation of complete and incomplete discoid lateral meniscus

ObjectivesThe aim of this retrospective study was (1) to evaluate the radiographic features to differentiate arthroscopically confirmed complete and incomplete discoid lateral meniscus (DLM) (2) to determine the cutoff values for any parameter that was found to differentiate complete from incomplete DLM. Materials and MethodsWe retrospectively analyzed plain knee radiographs of 130 arthroscopically proven DLM. Seventy-nine patients had complete DLM and 51 patients incomplete DLM. Knee radiographs from 52 patients with arthroscopically proven normal lateral meniscus acted as control group. Radiographic parameters measured included fibular height, lateral joint space, condylar cutoff sign, height of lateral tibial spine, obliquity of lateral tibial spine, squaring of the lateral femoral condyle, and cupping of the lateral tibial plateau. ResultsAmong radiographic parameters, high fibular head, widening of the lateral joint space and femoral condylar cutoff sign showed statistically significant (p<0.0001) differences between complete and incomplete DLM. At specific threshold points of fibular height<11mm, lateral joint space>6mm and condylar cutoff sign<0.80, the diagnosis of complete DLM revealed 87.3% sensitivity, 81.6% specificity and 78.4% positive predictive value (PPV) for the fibular height, 81.0% sensitivity, 86.6% specificity and 83.1% PPV for the lateral joint space, and 86.1% sensitivity, 83.5% specificity and 80% PPV for the condylar cutoff sign. ConclusionsRadiographic features of fibular height, lateral joint space and condylar cut off sign can be used for screening of a complete type of DLM. However, radiographs are not a reliable screening tool for an incomplete DLM. Level of evidenceIV, Case Series

Evaluation of posterior lateral femoral condylar hypoplasia using axial MRI images in patients with complete discoid meniscus.

Hypoplasia of the lateral femoral condyle has been reported in discoid lateral meniscus patients, but associated imaging findings in the axial plane have not been characterized. In this study, we aimed to identify differences in the lateral femoral condyle between patients with discoid lateral meniscus and those with normal menisci using axial MRI images. Twenty-three patients (24 knees) with complete discoid lateral meniscus, 43 (45 knees) with incomplete discoid lateral meniscus, and 50 with normal menisci (50 knees) were enrolled and distributed into three groups. Two new angles, posterior lateral condylar angle (PLCA) and posterior medial condylar angle (PMCA), were measured on axial MRI images; the posterior condylar angle (PCA) was also measured. Differences between the three groups in the PLCA, PMCA, PCA, and PLCA/PMCA were analysed. The predictive value of PLCA and PLCA/PMCA for complete discoid lateral meniscus was assessed. In the complete discoid lateral meniscus group, PLCA and PLCA/PMCA were significantly smaller compared with the normal meniscus group and the incomplete discoid lateral meniscus group (P<0.001). A significantly larger PCA was identified in the complete discoid lateral meniscus group compared with the incomplete discoid lateral meniscus group (P<0.05) and normal meniscus group (P<0.05). Both PLCA and PLCA/PMCA showed excellent predictive value for complete discoid lateral meniscus. Hypoplasia of the posterior lateral femoral condyle is typically seen in patients with complete discoid lateral meniscus. PLCA and PLCA/PMCA can be measured from axial MRI images and used as excellent predictive parameters for complete discoid lateral meniscus. Diagnostic study, Level III.

Usefulness of meniscal width to transverse diameter ratio on coronal MRI in the diagnosis of incomplete discoid lateral meniscus

To evaluate the clinical utility of the meniscal width to transverse diameter ratio (L/M ratio) of the lateral meniscus in the diagnosis of incomplete discoid lateral meniscus (IDLM) as compared with the arthroscopic diagnosis, meniscal width to tibial diameter ratio (L/T ratio) and conventional lateral meniscus width criteria. This retrospective study sample included 41 patients with IDLM who underwent knee magnetic resonance imaging (MRI) and arthroscopy, as well as 50 controls with normal lateral menisci. MRI examinations were interpreted independently by two radiologists, both of whom were blinded to clinical information and radiological reports. Assessment of meniscal width (L), maximal transverse diameter of the lateral meniscus (M), and transverse diameter of the tibia (T) was carried out on central coronal sections that were observed to pass through the medial collateral ligament. L/M and L/T ratios were calculated. These results were correlated with arthroscopic findings and analysed statistically using categorical regression analysis and non-parametric correlation analysis. Using arthroscopic findings as the standard of reference, sensitivity and specificity were calculated for: (1) 12, 13, 14, and 15 mm meniscal width thresholds; (2) 40%, 50%, 60%, and 70% L/M ratio thresholds; and (3) 15%, 18%, 20%, and 25% L/T ratio thresholds. The mean L/M ratio of the IDLM was approximately 67% and was statistically significantly higher than the control (44%). The best diagnostic discrimination was achieved using a threshold of 50%. The mean L/T ratio of the IDLM was approximately 23% and was statistically significant. The best diagnostic discrimination was achieved using a threshold of 18%. The threshold of 13 mm of meniscal width also showed high sensitivity and high specificity. The use of the L/M ratio or L/T ratio in combination with meniscal width criteria may be a useful method for evaluating IDLM.

Re-growth of an incomplete discoid lateral meniscus after arthroscopic partial resection in an 11 year-old boy: a case report

BackgroundDiscoid lateral meniscus is common in children. Arthroscopic partial resection is indicated in symptomatic cases generally achieving satisfactory results.Case presentationWe present a case of an incomplete discoid lateral meniscus of the right knee in an 11 year-old boy, treated with arthroscopic partial resection, which developed a re-growth of the remnant, restoring the pre-operative incomplete discoid shape. To the best of our knowledge this is the first report about re-growth of a discoid meniscus after surgery. Debate still exists regarding the etiology of a discoid meniscus. Some authors proposed it is the persistence of the normal stage during fetal development. However, most other authors believe it is anomalous and arises through variant morphogenesis. The re-growth of the discoid lateral meniscus following surgery in this patient seems to prove this latter theory. The residual growth of the knee involves also the lateral meniscus and that may have contributed to restoring the meniscus to the previous condition.ConclusionThis case report demonstrates discoid meniscal re-growth in a child. The growth spurt may have an impact on meniscal regeneration. Re-growth of the discoid lateral meniscus in our patient favors the hypothesis of variant morphogenesis.

Evaluation of the morphological variations of the meniscus: a cadaver study

The purpose of this study was to reveal the prevalence of the subtypes of the meniscus using human cadaver knees. Four hundred and thirty-seven cadaveric knees in 219 subjects (formalin fixed, Japanese population) with a median age of 83 years (54-97) were included in this study. All soft tissues surrounding the knee, excluding the meniscus, were resected, and macroscopic assessment of the meniscus was performed. Meniscus subtypes were classified as: (1) normal meniscus, (2) complete discoid, (3) incomplete discoid, (4) ring-shaped, and (5) double-layered. All subtypes of the meniscus were observed in the lateral meniscus. Complete discoid lateral meniscus was observed in 27 knees (6.2%), incomplete discoid lateral meniscus was observed in 139 knees (31.8%), ring-shaped lateral meniscus was observed in 4 knees (0.9%), and double-layered meniscus was observed in 2 knees (0.5%). This study reports the accurate prevalence of ring-shaped and double-layered meniscus. None of the subtypes were detected in the medial meniscus in this study. For clinical relevance, the results of this study can be useful in assisting the diagnosis of meniscus tear in clinical situations.

Diagnostic criterion to distinguish between incomplete and complete discoid lateral meniscus on MRI

To determine a new cutoff value that can further distinguish between the incomplete and complete discoid lateral meniscus (DLM). Twenty-one cases of incomplete DLM and 42 cases of complete DLM without tear were included. In all, 105 patients with normal lateral menisci were included as a control group. We measured the ratio of the shortest width of the lateral meniscus to the longest width of the tibia (ratio 1) and the ratio of the shortest width of the medial meniscus to the shortest width of the lateral meniscus (ratio 2). By applying a cutoff value of ratio 1 as 0.32 between two incomplete and complete DLM groups, the proportion of the complete and incomplete DLM diagnosed cases among the true cases were 84% and 94%, respectively. By applying a cutoff value of ratio 2 as 0.40 between two incomplete and complete DLM groups, the proportion of the complete and incomplete DLM diagnosed cases among the true cases were 84% and 75%, respectively. A cutoff value of 0.32 using the ratio of the shortest width of the lateral meniscus and the longest width of the tibia are probably useful to help distinguish between complete DLM and incomplete DLM. Additionally, the new ratio using the width of the medial meniscus is also useful to improve distinguishing between the types of DLM.

Incidence of Bilateral Discoid Lateral Meniscus in An Asian Population: An Arthroscopic Assessment of Contralateral Knees

To investigate the incidence of bilateral discoid lateral meniscus (DLM) and to evaluate the arthroscopic features of lateral meniscus in asymptomatic contralateral knees in an Asian population who presented with symptomatic DLMs. This study prospectively enrolled 52 consecutive patients who underwent arthroscopic procedures for symptomatic DLMs (31 complete and 21 incomplete) and who consented to the examination of the contralateral knee at the time of arthroscopy. Types of DLMs and of meniscus tears were assessed by use of arthroscopic findings. Preoperative and postoperative functional outcomes were evaluated with Lysholm and Tegner activity scores. Arthroscopic examinations showed 21 complete DLMs, 19 incomplete DLMs, 11 normal lateral menisci, and 1 ring-shaped lateral meniscus in contralateral knees. The incidence of bilateral DLM in our study population was 79% (41 of 52 contralateral knees). Furthermore, 65% of patients (34 pairs of knees) had the same DLM types. In addition, 3 pairs of knees with complete DLMs had menisci of different thicknesses. DLM tears were observed in 2 contralateral knees (1 radial and 1 longitudinal) and were treated by partial central meniscectomy. This study provides evidence of the high prevalence of bilateral DLM in an Asian population.

Arthroscopic treatment for symptomatic discoid lateral meniscus during childhood

The purpose of this study was to review the operative long-term results of a large cohort of children treated arthroscopically for a symptomatic discoid lateral meniscus. We retrospectively reviewed the arthroscopic procedures performed on 104 knees (97 patients) between 1990 and 2006 to treat symptomatic discoid lateral meniscus in children. The median age at the time of surgery was 8 years (range 2.5-13.9 years). The follow-up was 8.5 ± 2.5 (mean ± SD) years (median 9, range 2-18.5 years). In this series, young children (2-7 years) usually presented complete discoid menisci with deficit in extension and little pain. The meniscal tissue was almost degenerated, and subtotal meniscectomy was performed. Children aged from 8 to 14 years referred to our institute typically presented a symptomatic tear (pain and swelling joint with snap) of a complete or incomplete discoid lateral meniscus, usually pursuant to a trauma. The treatment performed in this group was a partial meniscectomy. Clinical results at long-term follow-up show better results for subtotal meniscectomies than for partial ones. The results showed the long-term efficacy of arthroscopic treatment of a symptomatic discoid lateral meniscus. On the basis of this study, subtotal meniscectomies in younger patients are preferable when meniscal tissue is degenerated. In older children, we recommend to preserve meniscal tissue as much as possible. In younger patients submitted to subtotal meniscectomies, some adaptation of the knee to stress activity may occur. Therapeutic case series, Level IV.

Bilateral Discoid Lateral Meniscus in Knees: Evaluation of the Contralateral Knee in Patients With Symptomatic Discoid Lateral Meniscus

The aim of this study was to analyze, by use of magnetic resonance imaging (MRI), the contralateral discoid lateral meniscus (DLM) status of 33 patients who underwent an operation for a symptomatic DLM. This diagnostic study included 33 consecutive patients who underwent arthroscopic surgery for a unilaterally symptomatic DLM. All patients' contralateral knees were checked with simple radiographs and MRI scans. Knees were also evaluated through physical examinations and a clinical scoring system. On the basis of the MRI findings, DLM was categorized into 3 types: normal type, incomplete discoid type, and complete discoid type. The tear patterns of the lateral menisci as imaged by radiographs and the associated chondral lesions imaged by MRI were analyzed by consensus in the bilateral knees. All but 1 of the contralateral, asymptomatic knees (97%) were diagnosed by MRI to have complete or incomplete DLM. DLMs with tears were found in the contralateral knees in 11 cases (33%), and chondral lesions were found in 4 (12%) of the complete discoid type cases. On radiography, 23 (70%) of the 33 contralateral knees showed characteristic findings of DLM. We found that 29 pairs of knees (88%) had the same lateral meniscus shape on MRI. A κ analysis showed significant and good agreement between the radiographic findings, the tear pattern of the lateral menisci, and the associated chondral lesions on MRI scans in bilateral knees. DLM commonly occurs bilaterally in patients with symptomatic, unilateral surgical DLM, although this finding was applicable only to young, Asian male patients. Characteristic radiographic findings and the MRI findings of symptomatic DLM patients were significantly correlated between both knees. Level I, testing of previously developed diagnostic criteria in a series of consecutive patients with universally applied reference gold standard.

Ring meniscus mistaken for incomplete discoid meniscus: a case report and review of literature

Ring meniscus is a known but rare abnormal variant of a meniscus. An incomplete discoid meniscus or an old bucket handle tear of a meniscus can be easily mistaken for a ring meniscus. In this case; during the first arthroscopy, the ring lateral meniscus was mistaken for an incomplete discoid lateral meniscus. On repeat arthroscopy, it was confirmed as ring lateral meniscus.

Radial Displacement of Lateral Meniscus After Partial Meniscectomy

Radial displacement or extrusion of the meniscus has been reported as a complication after meniscal transplantation and is sometimes observed in knees with advanced osteoarthritis. In this report, the case of a patient with radial displacement of the lateral meniscus after partial meniscectomy is presented. He had an incomplete discoid lateral meniscus with an anterior horn tear. The inner portion of the lateral meniscus was excised to leave a width of 8 to 10 mm. However, follow-up magnetic resonance imaging showed radial displacement of the mid-body of the lateral meniscus and a compatible finding of chondromalacia of the lateral compartment of the knee.