Risk factors for articular cartilage lesions in symptomatic discoid lateral meniscus

Age and medial compartmental OA were important predictors of the lateral compartmental OA in the discoid lateral meniscus: Analysis using machine learning approach

PURPOSE

The objective of this study was to develop a machine learning model that would predict lateral compartment osteoarthritis (OA) in the discoid lateral meniscus (DLM), from which to then identify factors contributing to lateral compartment OA, with a key focus on the patient's age.

METHODS

Data were collected from 611 patients with symptomatic DLM diagnosed using magnetic resonance imaging between April 2003 and May 2022. Twenty features, including demographic, clinical and radiological data and six algorithms were used to develop the predictive machine learning models. Shapley additive explanation (SHAP) analysis was performed on the best model, in addition to subgroup analyses according to age.

RESULTS

Extreme gradient boosting classifier was identified as the best prediction model, with an area under the receiver operating characteristic curve (AUROC) of 0.968, the highest among all the models, regardless of age (AUROC of 0.977 in young age and AUROC of 0.937 in old age). In the SHAP analysis, the most predictive feature was age, followed by the presence of medial compartment OA. In the subgroup analysis, the most predictive feature was age in young age, whereas the most predictive feature was the presence of medial compartment OA in old age.

CONCLUSION

The machine learning model developed in this study showed a high predictive performance with regard to predicting lateral compartment OA of the DLM. Age was identified as the most important factor, followed by medial compartment OA. In subgroup analysis, medial compartmental OA was found to be the most important factor in the older age group, whereas age remained the most important factor in the younger age group. These findings provide insights that may prove useful for the establishment of strategies for the treatment of patients with symptomatic DLM.

LEVEL OF EVIDENCE

Level III.

Medial Discoid Meniscus: A Rare Case Report

The meniscus is a glossy white structure found in the knee between the femoral condyle and tibial plateau in the medial and lateral aspects of both knees. The main purposes of the meniscus are to enhance joint congruity and stability, transmit load, and absorb stress. A rare type of anomaly of the meniscus shape is called discoid meniscus, which presents as an atypical shape also known as disk cartilage. This report presents a 13-year-old male with a history of left knee pain after a fall. The pain was stabby in nature with a decrease in range of motion in the left knee and positive McMurray and Apley's tests on examination. The patient was treated by arthroscopic saucerization, and the procedure was successful. The patient had a good postoperative outcome after two months of follow-up.

Mid-term study on the effects of arthroscopic discoid lateral meniscus plasty on patellofemoral joint: An observational study

In the present study, we aimed to investigate the clinical outcomes of arthroscopic discoid lateral meniscus (DLM) plasty and the adaptive changes in the patellofemoral joint after surgery. From September 2010 to March 2012, 25 patients with DLM injuries who underwent arthroscopic meniscus plasty were enrolled in the prospective study. All patients underwent clinical evaluation before the operation and at the last follow-up, and imaging evaluation was performed by upright magnetic resonance imaging before and 1 month after the operation as well as at the last follow-up. Clinical evaluation included Lysholm score, Kujala score, McMurray's sign, patellar mobility, patella grind test, and quadriceps atrophy. Imaging evaluation included bisect offset index, patella tilt angle (PTA), and cartilage damage. Lysholm score, Kujala score, McMurray's sign, and quadriceps atrophy at the last follow-up were significantly improved compared with the preoperative levels (P < .05). At the last follow-up, there were no statistical differences in patella mobility and patella grind test compared with the preoperative levels. In addition, bisect offset index and PTA showed a dynamic trend of rising and then falling over time (P < .05). At 1 month after the operation, bisect offset index and PTA were significantly increased compared with the preoperative levels or the values at the last follow-up (P < .05), while there were no differences between the preoperation and the last follow-up. Cartilage damage became worse with time (P < 0.05), and the 2 were positively correlated (Spearman = 0.368). At the last follow-up, the degree of cartilage damage was significantly increased compared with the preoperative level (P < .017), while there was no significant difference between the 1-month postoperative grade and the preoperational grade or the last follow-up grade. The effect of arthroscopic DLM plasty on the patellofemoral joint was dynamic, with the position of the patella deviating in the early stages and recovering in the mid-term, especially when the knee was in the biomechanical standing position. In addition, the patellofemoral joint cartilage might undergo accelerated degeneration after the operation, while the mid-term effect of the operation was positive, and the patellofemoral joint function was acceptable.

Update on imaging of the discoid meniscus

Discoid menisci represent a range of morphological meniscal variants, most commonly involving the lateral meniscus. Clinical presentation ranges from an asymptomatic incidental finding to snapping, pain, swelling and reduced range of knee movement. Symptomatic presentation of discoid menisci is usually due to meniscal tears and instability resulting from abnormal meniscal morphology and ultrastructure, with absent peri-meniscal ligamentous and meniscocapsular attachments characteristic of the Wrisberg sub-type. This article reviews the current classification systems of discoid menisci, gross morphological characteristics of each sub-type and ultrastructure. Clinical presentation, arthroscopic findings and indirect radiological diagnostic criteria are described, as are the MRI findings of normal and pathological discoid menisci. Current concepts of surgical management and outcomes of the discoid meniscus are also briefly discussed.

Multivariate ordered logistic regression analysis of the postoperative effect of symptomatic discoid lateral meniscus

INTRODUCTION

The postoperative effect of arthroscopy in the treatment of symptomatic discoid lateral meniscus (DLM) varies greatly among individuals. Therefore, this study aims to investigate the factors affecting the postoperative outcomes of symptomatic DLM.

MATERIALS AND METHODS

According to the inclusion and exclusion criteria, patients with symptomatic single-knee DLM who underwent arthroscopic surgery at our hospital from 9/2008 to 9/2015 were included. Retrospectively collected 16 factors probably affecting postoperative outcomes. The Ikeuchi grade system was used to evaluate the knee joint function. Univariate analysis was performed by Kruskal-Wallis rank-sum test or Mann-Whitney U test, and multivariate analysis by ordered logistic regression. P < 0.05 was considered statistically significant.

RESULTS

A sum of 502 patients was included, including 353 females (70.3%) and 149 males (29.7%). Difference between preoperative and postoperative Ikeuchi grade was statistically significant (P < 0.001). Female was bad to obtain a good Ikeuchi grade (P = 0.009, OR 0.458). Outerbridge grade (P = 0.018, OR 0.638) was negatively correlated with Ikeuchi grade. BMI (P = 0.001, OR 0.875) and work intensity (P = 0.020, OR 0.611) were inversely correlated with Ikeuchi grade. Age of onset (P < 0.001, OR 0.956) and symptoms duration (P < 0.001, OR 0.988) were negatively correlated with Ikeuchi grade. Besides, compared to total meniscectomy, meniscoplasty with a repair was an unfavourable factor for Ikeuchi grade (P = 0.044, OR 0.245).

CONCLUSIONS

With the increase of BMI, work intensity, age of onset, duration of symptoms, and the severity of cartilage lesion, the postoperative results become worse. Moreover, female and meniscoplasty with repair are risk factors for the postoperative outcomes.

Discoid lateral meniscus: current concepts

The discoid meniscus is a congenital morphological abnormality encountered far more commonly on the lateral than the medial side. The discoid lateral meniscus (DLM) is more prevalent in Asia with an incidence of 10%-13%, than in the Western world with an incidence of 3%-5%. DLM can be bilateral in more than 80% cases. Due to its abnormal shape and size, the discoid meniscus is prone to tearing and has an impact on gait mechanics. The discoid meniscus has deranged collagen arrangement and vascularity which can have implications for healing after a repair. Patients with a DLM may or may not be symptomatic with mechanical complaints of locking, clicking, snapping or pain. Symptoms often arise due to a tear in the body of the meniscus or a peripheral detachment. Asymptomatic patients usually do not require any treatment, while symptomatic patients who do not have locking are managed conservatively. When a peripheral detachment is present, it must be stabilised while preserving the meniscus rim to allow transmission of hoop stresses. Rehabilitation after surgery is highly individualised and return to sports is possible after more than 4 months in those undergoing a repair. The functional outcomes and onset of radiographic arthritis after saucerisation and repairing a discoid meniscus are better in the long term, compared with a subtotal meniscectomy. However, there is no compelling evidence currently favouring a repair as results deteriorate with increasing follow-up. Poor prognosis is reported in patients undergoing a total meniscectomy, a higher age at presentation and valgus malalignment.

Factors influencing postoperative outcomes in patients with symptomatic discoid lateral meniscus

BACKGROUND

Due to its abnormal morphology and ultrastructure, discoid lateral meniscus (DLM) is prone to tear and degeneration, leading to clinical symptoms. Arthroscopy is the main treatment for symptomatic DLM; however, postoperative outcomes vary widely due to the effects of diverse factors. This research aims to explore the factors influencing postoperative outcomes of symptomatic DLM.

METHODS

Patients with DLM who underwent arthroscopic surgery at our hospital from 9/2008 to 9/2015 were enrolled according to the inclusion and exclusion criteria. Fourteen variables, including sex, body mass index (BMI) and other variables, were chosen as factors for study. Knee function was assessed using the International Knee Documentation Committee (IKDC) score. Univariate analyses (Mann-Whitney U test or Kruskall-Wallis rank sum test) and multivariate analyses (ordinal logistic regression) were used to identify the factors that influenced postoperative outcomes. P < 0.05 was considered statistically significant.

RESULTS

A total of 502 patients, including 353 females (70.3%) and 149 males (29.7%), were enrolled. The median IKDC score postoperatively (87.4; range, 41.4 ~ 97.7; IQR, 14.6) was higher than that preoperatively (57.6; range, 26.9 ~ 64.9; IQR, 9.7) (P < 0.001). Male sex was predictive of a higher IKDC score (P = 0.023, OR = 1.702). Compared with BMI ≥25 kg/m², < 18.5 kg/m² was associated with better IKDC score (P = 0.026, OR = 3.016). Contrasting with age of onset ≥45 years, ≤14 years (P < 0.001, OR = 20.780) and 14 ~ 25 years (P < 0.001, OR = 8.516) were associated with better IKDC score. In comparison with symptoms duration> 24 months, IKDC scores for patients with symptoms duration ≤1 month (P = 0.001, OR = 3.511), 1 ~ 6 months (P < 0.001, OR = 3.463) and 6 ~ 24 months (P < 0.001, OR = 3.254) were significantly elevated. Compared to Outerbridge grade III ~ IV, no injury (P < 0.001, OR = 6.379) and grade I (P = 0.01, OR = 4.332) were associated with higher IKDC score.

CONCLUSIONS

Arthroscopic treatment of symptomatic DLM is safe and effective, but its clinical efficacy is affected by many factors. Specifically, male sex, BMI < 18.5 kg/m², age of onset < 25 years (especially < 14 years) and symptoms duration < 24 months are conducive to good postoperative outcomes. However, combined articular cartilage injury (Outbridge grade ≥ 2) reduces postoperative effect.

Torn discoid lateral meniscus is associated with increased medial meniscal extrusion and worse articular cartilage status in older patients

PURPOSE

To compare the clinical, imaging, and arthroscopic characteristics of the torn discoid lateral meniscus (TDLM) in patients greater than 40 years of age with matched controls.

METHODS

One hundred and ninety-four older patients (211 knees) who underwent arthroscopic surgery for a TDLM were consecutively recruited (Group 1). Another 211 age- and sex-matched controls with a torn semilunar lateral meniscus were included in this study (Group 2). Statistical analyses were used to determine the differences in the clinical, imaging, and arthroscopic characteristics between the two groups.

RESULTS

In our series, more severe medial meniscal extrusion on magnetic resonance imaging was present in Group 1 than in Group 2 and more serious osteoarthritic changes were observed in both the medial and lateral compartments in Group 1. Under the same conditions, chondral lesions in the knee were more serious in Group 1 than in Group 2 when patients were subgrouped according to the presence of a horizontal tear or complex tear.

CONCLUSIONS

In the present study, older patients with a torn discoid lateral meniscus exhibited greater and more severe medial meniscal extrusion and more serious osteoarthritis. Therefore, knees with a discoid lateral meniscus displaying medial meniscal extrusion should be monitored carefully with long-term follow-up, because a medial meniscal extrusion may increase the risk of progression to degenerative osteoarthritis of the medial compartment. Regarding the clinical relevance, these findings will be helpful in further revealing that a torn discoid lateral meniscus may affect not only the cartilage in the lateral compartment but also the cartilage in the medial compartment and medial meniscal extrusion.

LEVEL OF EVIDENCE

III.

The Sensitivity and Specificity of Preoperative History, Physical Examination, and Magnetic Resonance Imaging to Predict Articular Cartilage Injuries in Symptomatic Discoid Lateral Meniscus

BACKGROUND

Discoid lateral meniscus (DLM) is a morphologic variant in which concomitant articular cartilage defects lead to poor outcomes. The purpose of this study was to quantify the prognostic ability of history, physical examination, and magnetic resonance imaging (MRI) to identify arthroscopically confirmed articular cartilage injury in pediatric and adolescent DLM patients.

METHODS

An analysis of 34 consecutive patients (mean, 12.5 y) who underwent surgical treatment for DLM. Patients were grouped based on arthroscopic findings for the presence or absence of articular cartilage injury. All patients underwent standard preoperative history and physical examination, and MRI of their symptomatic knee. Separate discriminant functional analyses were performed using history (age, sex, symptoms lasting >6 mo, traumatic history), physical examination (presence of clunk, extension block, mechanical symptoms), and MRI findings (chondral injury, meniscal degeneration, meniscal morphology) to determine their sensitivity and specificity in prediction of articular cartilage lesions.

RESULTS

The sensitivity and specificity of history alone was 71.4% and 75.0%, respectively; physical examination alone was 64.3% and 60%, respectively; and of MRI findings alone was 60% and 66.7%, respectively. A stepwise discriminant functional analysis found that duration of symptoms and extension block were the optimal contributors with a 78.5% sensitivity and 80% specificity.

CONCLUSIONS

Preoperative history had the highest sensitivity and specificity compared with physical examination and MRI findings for predicting articular cartilage injury at the time of DLM surgery. These findings may assist in setting expectations for patients with regard to surgical planning and recovery and also to counsel patients with asymptomatic, incidental DLM which factors may risk chondral injury and warrant early return for evaluation.

LEVEL OF EVIDENCE

Level II-retrospective prognostic comparative study.

High tibial osteotomy accelerates lateral compartment osteoarthritis in discoid meniscus patients

PURPOSE

The valgus high tibial osteotomy (HTO) in patients with medial osteoarthritis and discoid lateral meniscus can result in increased load on the lateral compartment and hence a higher chances of tear. This may accelerate the progression of osteoarthritis on lateral compartment. We, therefore, carried out the case control study with a hypothesis that an HTO would accelerate the progression of osteoarthritis (OA) on lateral compartment in patients with complete discoid meniscus.

METHODS

The records of all patients with open wedge HTO from 2008 to 2012 were evaluated for complete lateral discoid meniscus. The patient who had a valgus HTO with or without partial meniscectomy for medial compartmental OA was included for this study. Cases to control were chosen to match age, body mass index (BMI), pre-operative osteoarthritis grade, and deformity angles in ratio 1:2. Patient's records were studied for demographic data, clinical examination records, and pre-operative knee functional scores and radiological scores and were compared with post-operative data.

RESULTS

Thirty-six patients out of 674 patients, who underwent an HTO, consisted of discoid meniscus group. 72 patients were chosen as control group. Four patients showed progression of OA on the lateral compartment in discoid group compared to none in control group. Although control groups showed a little bit better functional outcomes, there were no statistical differences between two groups (n.s.).

CONCLUSION

The high tibial osteotomy could result in accelerated lateral compartment osteoarthritis in patients with complete discoid meniscus, and the procedure should be used with caution in such patients.

LEVEL OF EVIDENCE

IV.

Posteriorly inserted anterior cruciate ligament in knees with discoid lateral meniscus corresponding to bony morphological characteristics of femoral lateral condyle

PURPOSE

Discoid meniscus often causes mechanical problems and needs surgical treatment at an early age. However, many aspects of its morphological development and changes remain unknown. The purpose of this study was to investigate the insertion of the femoral anterior cruciate ligament (ACL) via the behind-ACL approach and the morphology of the lateral femoral condyle to which the ACL attaches to clarify the morphological characteristics of the knee with discoid lateral meniscus (DLM).

METHOD

Sixty-six patients with meniscus injury who underwent arthroscopic surgery were retrospectively reviewed. Preoperative plane radiographs were reviewed. To evaluate the shape of the femoral condyle, the ratio of the medial and lateral condyles, obliquity of the inter-epicondylar line, and the prominence ratio were assessed. From the arthroscopic observation using the behind-ACL approach, the insertion of the femoral ACL was classified as low, middle, and high based on the height from the deepest area of the articular surface to the direct insertion, including fibrous extension from the joint surface at 90° flexion.

RESULTS

Twenty-nine patients had DLM (DLM group), and 37 patients had a semilunar meniscal injury (non-DLM group). The ratio of the lateral femoral condyle, obliquity of the inter-epicondylar line, and prominence ratio in the DLM group were significantly smaller than those in the non-DLM group. On the other hand, no significant difference in the ratio of the medial femoral condyle was observed. Arthroscopic evaluation revealed that the femoral ACL was significantly inserted lower in the DLM group than in the non-DLM group.

CONCLUSION

The femoral ACL with DLM was inserted close to the femoral joint surface with morphological abnormality in the knees with DLM related to hypoplasic of the lateral femoral condyle.

The adaptive change of patellofemoral joint after arthroscopic discoid lateral meniscus plasty: An observational study

The purpose of this study was to investigate the patellofemoral joint adaptive changes after discoid lateral meniscus (DLM) plasty.Forty-one patients with unilateral complete type DLM tears were included in this study. Demographic variables, including gender, age, body mass index (BMI), injury to operation interval, type of injury, and follow-up time, were recorded. The evolution of physical examination, imaging index, and functional score were analyzed by Chi-squared test, Wilcoxon signed ranks test, and Friedman test. Mann-Whitney test was used to analyze the difference at different time points between group PFI > 1.6 and PFI < 1.6.After the patients received arthroscopic DLM plasty, the positive rate of Patella grinding test increased from 19.5% to 29.3%, and it showed significant increased at last follow-up time point (48.8%) (P = .005). Mechanical axis deviation (MAD) significant decreased from -0.7 ± 2.1 mm to -9.4 ± 3.2 mm (P < .001). Lateral patellofemoral angle (LPFA) and lateral shift distance (LSD), respectively, decreased from 11.9 ± 5.8° and 1.0 ± 4.0 mm to 7.2 ± 4.5° and -0.5 ± 3.3 mm (P < .001). Patellofemoral index (PFI) increased from 1.7 ± 0.3 to 1.9 ± 0.4 (P < .001). Kujala score and Lysholm score, respectively, increased from 65.9 ± 10.0 and 85.2 ± 6.4 mm to 61.8 ± 10.2 and 89.5 ± 5.0 (P < .001). Only LSD in group > 1.6 were significant lower than those in group < 1.6 (>1.6: -1.5 ± 2.8, -1.6 ± 2.7, -1.5 ± 2.6; <1.6: 0.8 ± 3.4, 0.4 ± 3.6, 0.6 ± 2.8. P = .010,.038,.011) at the 3 postoperative follow-up time points.After arthroscopic plasty for complete type DLM which decreased the thickness and width of the residual meniscus, in turn causing the varus deformity significantly decreased or a valgus inclination developed. Moreover, the consequent changes of patellofemoral joint caused a certain amount of patellar tilt and patellar dislocation, might aggravated the symptomatic anterolateral knee pain or the lateral patellar compression syndrome.

Knee Pain and Mobility Impairments: Meniscal and Articular Cartilage Lesions Revision 2018

The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these revised clinical practice guidelines is to review recent peer-reviewed literature and make recommendations related to meniscus and articular cartilage lesions. J Orthop Sports Phys Ther. 2018;48(2):A1-A50. doi:10.2519/jospt.2018.0301.

Risk factors for radiographic progression of osteoarthritis after partial meniscectomy of discoid lateral meniscus tear

INTRODUCTION

Partial meniscectomy has been preferred in the treatment of discoid lateral meniscus (DLM) with tear, rather than total or subtotal meniscectomy, which could lead to late radiographic degenerative changes.

HYPOTHESIS

One or more risk factors contribute to radiographic progression of osteoarthritis after partial meniscectomy of DLM tear.

MATERIAL AND METHODS

Inclusion criteria were consecutive patients who underwent arthroscopic surgeries for DLM tear from January 2005 to December 2010 by one surgeon. Exclusion criteria were preoperative osteoarthritis with KL grade 3 or more, osteochondritis dissecans, minimal width of meniscal remnant less than 6mm after meniscectomy, meniscal repair of an unstable discoid meniscus, age over 60years, loss to follow-up for a minimum of 5years and simultaneous surgery on articular cartilage or anterior cruciate ligament. According to the KL grade at the last follow-up, all enrolled knees were sorted into no progression to knee osteoarthritis (KL grade 1 or 2 - NOA) and progression to osteoarthritis (KL grade 3 or 4 - POA) groups. Multivariate logistic regression was used to analyze the risk factors of high-grade osteoarthritis.

RESULTS

In comparison with NOA group (n=135) and POA group (n=67), prolonged symptom duration, increased relative percentage of DLM thickness (RPDT) and the presence of horizontal tear were significant risk factors. The presence of horizontal tear (P=0.048, adjusted OR=19.364) was the strongest predictor, compared with prolonged symptom duration (P=0.030, adjusted OR=1.150) and increased RPDT (P=0.003, adjusted OR=1.377).

DISCUSSION

Horizontal tear, prolonged symptom duration, and increased RPDT are significant risk factors for radiographic progression to high-grade osteoarthritis after partial meniscectomy of DLM tear with a minimum follow-up of 5years.

LEVEL OF EVIDENCE

III, case-control study.

Accelerated degeneration of the discoid lateral meniscus after medial opening wedge high tibial osteotomy

PURPOSE

This study was undertaken to report clinical outcomes after high tibial osteotomy (HTO) in patients with a discoid lateral meniscus and to determine (1) whether discoid lateral meniscus degeneration by magnetic resonance imaging (MRI) progresses after HTO and (2) whether this progression adversely affects clinical results.

METHODS

The records of 292 patients (292 knees) who underwent medial opening HTO were retrospectively reviewed, and discoid types and grades of lateral meniscus degeneration as determined by MRI were recorded preoperatively. Of the 292 patients, 17 (5.8%) had a discoid lateral meniscus, and postoperative MR images were obtained at least 2 years after HTO for 15 of these 17 patients.

RESULTS

American Knee Society (AKS) pain, knee and function scores significantly improved in the 15 patients after surgery (p < 0.001). Eight (53%) had an incomplete and 7 (47%) had a complete discoid lateral meniscus. By preoperative MRI, the distribution of meniscal degeneration was as follows: grade 1, 4 patients; grade 2, 7 patients; and grade 3, 4 patients. At the final follow-up, the distribution of degeneration was as follows: grade 1, 2 patients; grade 2, 5 patients; and grade 3, 8 patients. Two patients with grade 3 degeneration who did not undergo partial meniscectomy showed tear progression. Thus, 8 of the 15 patients (53%) experienced progressive discoid meniscal degeneration after HTO. Median AKS pain score was significantly lower in the progression group than in the non-progression group (40 vs 45, respectively).

CONCLUSION

The results of this study suggest that increased load on the lateral compartment after HTO can accelerate discoid lateral meniscus degeneration by MRI and caution that when a discoid lateral meniscus is found by preoperative MRI, progressive degeneration may occur after HTO and clinical outcome may be adversely affected.

LEVEL OF EVIDENCE

Therapeutic study, Level IV.

Discoid lateral meniscus tears and concomitant articular cartilage lesions in the knee

PURPOSE

The purpose of this study was to investigate the relation between isolated discoid lateral meniscus (DLM) tears and the presence of articular cartilage lesions.

METHODS

From January 2010 to January 2012, 252 consecutive patients diagnosed with an isolated DLM tear during an arthroscopic procedure were included in this study. Demographic variables, including gender, age, body mass index (BMI), traumatic history, time course, and date of the DLM tear, were recorded. The relation between DLM tears and the presence of articular cartilage lesions was analyzed by the χ(2) test. Logistic regression analysis was used to analyze the relation between these variables and articular cartilage lesions.

RESULTS

Of the patients with DLM tears, 67 (26.6%) also had articular cartilage lesions. The most common type of DLM tear was the complex tear (46.8%). The most common location of articular cartilage lesions was the lateral tibial plateau (11.6%). Lesions on the opposing articular surfaces of the lateral compartment and patellofemoral joint of the knee were found in 12 patients (4.8%) and 11 patients (4.4%), respectively. There were no significant differences in the incidences of articular cartilage lesions in patients with different types of DLM tears (P > .05). Gender (odds ratio [OR], 2.289; P = .012), BMI (OR, 1.991; P = .023), and time course (OR, 2.050; P = .034) were significantly associated with articular cartilage lesions.

CONCLUSIONS

DLM tears were more common in the context of degenerative tears. There was no significant difference in the incidence of articular cartilage lesions among patients with different types of DLM tears. Female patients, patients with a BMI greater than 23.0 kg/m(2), or patients with a time course of greater than 6 months were more frequently observed to also have articular cartilage lesions.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Does torn discoid meniscus have effects on limb alignment and arthritic change in middle-aged patients?

BACKGROUND

The purpose of the present study was to evaluate the characteristics of the discoid lateral meniscus in patients more than forty years of age. We studied whether a torn discoid lateral meniscus that has no treatment until middle age would increase the tendency of the knee to develop a varus deformity and investigated the correlation between torn discoid lateral meniscus and osteoarthritis.

METHODS

We retrospectively reviewed the records for 164 knees in 158 patients who were more than forty years old and who underwent a knee arthroscopic procedure from 1992 to 2007. The mean age at the time of surgery was fifty-two years. Comparative evaluation of the clinical and radiographic differences between the eighty-four patients with torn discoid lateral meniscus (Group A) and the seventy-four patients with a torn normally shaped lateral meniscus (Group B) was carried out.

RESULTS

Preoperative standing anteroposterior radiographs, which were made for all patients, showed that varus deformity was more common in Group A than in Group B and that osteoarthritic changes in both the medial and lateral compartments were also more common in Group A. With regard to chondral injury, Outerbridge grade-3 or 4 involvement was identified in 46% of the knees in Group A and 18% of the knees in Group B.

CONCLUSIONS

In the present study of middle-aged patients, those with a torn discoid lateral meniscus had a higher prevalence of varus knee deformity and a higher prevalence of osteoarthritis. Knees with a discoid lateral meniscus that have diminished valgus alignment should be monitored carefully with long-term follow-up because a discoid lateral meniscus may increase the risk for progression to degenerative knee osteoarthritis.

Symptomatic bilateral discoid menisci in children: a comparison with unilaterally symptomatic patients

BACKGROUND

In previous studies, 5% to 20% of patients with a discoid lateral meniscus eventually require surgery bilaterally for symptomatic discoid menisci. However, there are little published data specifically on children who require treatment for discoid menisci in both knees. The purpose of this study is to identify differences in clinical and arthroscopic findings between children who require bilateral versus unilateral treatment for symptomatic discoid lateral menisci.

METHODS

We retrospectively reviewed the records of all patients aged 18 years or younger requiring treatment of discoid lateral meniscus between 1998 and 2007. Data were collected on 16 patients (32 knees) with symptomatic bilateral discoid menisci and 60 patients treated unilaterally with an asymptomatic contralateral knee.

RESULTS

At initial presentation, children who were treated bilaterally for discoid menisci were younger than those treated unilaterally (10.4 vs. 12.5 y; P=0.021). Patients under 12 years of age were 4.6 times more likely to eventually require surgery on both knees (P=0.015). Watanabe classification was as follows: complete, 65% bilateral versus 30% unilateral; incomplete, 22% bilateral versus 68% unilateral; and Wrisberg, 13% bilateral versus 2% unilateral (P<0.001). The odds of current or future bilateral symptoms requiring treatment were 4.5 times higher in patients with a complete discoid meniscus (P=0.0017) and 8.4 times higher in those with a Wrisberg type (P=0.048). A tear of the lateral meniscus was more likely to be found intraoperatively in unilateral knees than bilateral (90% vs. 72%; P=0.037).

CONCLUSIONS

Patient education and long-term follow-up are important for children who present with a discoid meniscus at a young age or with a complete or Wrisberg type, as these patients may be at increased odds of symptomatic discoid meniscus in the contralateral knee, even several years later. Furthermore, evaluation and treatment of discoid lateral meniscus requires vigilance for meniscal tears.

LEVEL OF EVIDENCE

Prognostic study, level III.

Discoid lateral meniscus in children: magnetic resonance imaging after arthroscopic resection

PURPOSE

The discoid meniscus is a common meniscal anomaly. Symptomatic discoid menisci treated by arthroscopic surgery were examined preoperatively and postoperatively by magnetic resonance imaging (MRI). Aim of this study was to quantify the amount of meniscal resection when treating discoid meniscus in children by partial meniscectomy. The hypothesis was that partial meniscectomy left sufficient amounts of meniscal tissue.

METHODS

A quantitative evaluation of meniscal size comparing preoperative and postoperative data after partial meniscectomy was performed by MRI (n = 6). The anteroposterior meniscal diameter and anterior and posterior thickness were measured. The relative postoperative thickness to preoperative thickness was defined. All patients were graded according to Lysholm score and Ikeuchi knee scale.

RESULTS

The quantitative MRI evaluation showed a pronounced reduction of the anteroposterior meniscal diameter (42%) and anterior thickness (41%) after partial meniscectomy, whereas the posterior thickness showed a mean increase of 50%. According to Ikeuchi, all clinical postoperative findings were excellent and displayed an increase in Lysholm score.

CONCLUSIONS

MRI findings showed that the amount of remaining tissue after partial meniscectomy was smaller than aspired. Especially in the anterior joint, the final size of remaining meniscal tissue was overestimated intraoperatively. It may be concluded that in arthroscopic partial meniscectomy, the final meniscal size, especially in the anterior part of the joint, is difficult to assess. As it is known that the extent of meniscal resection plays a crucial role in the clinical course of discoid menisci, these data claim retentiveness in resecting meniscal tissue.

Arthroscopic treatment for symptomatic discoid lateral meniscus during childhood

PURPOSE

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.

METHODS

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).

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Medial and lateral discoid menisci: a case report

Discoid menisci on both medial and lateral tibial plateau are very rare abnormalities. We report a 44-year-old woman with bilateral medial and lateral discoid menisci. She also had anomalous insertion of discoid medial meniscus to anterior cruciate ligament, and pathologic medial patellar plica on the right knee. Meniscectomies has been performed for her torn discoid menisci with satisfactory result on the latest follow-up.