Can early diagnosis and partial meniscectomy improve quality of life in patients with lateral discoid meniscus?

Pediatric discoid meniscus: can magnetic resonance imaging features coupled with clinical symptoms predict the need for surgery?

BACKGROUND

Magnetic resonance imaging (MRI) criteria for evaluating discoid meniscus is limited in the pediatric population.

OBJECTIVE

To assess MRI features of intact discoid meniscus and correlate with clinical outcomes.

MATERIALS AND METHODS

In this institutional review board (IRB)-approved retrospective cohort study, knee MRIs at our institution from 2008 to 2019 were reviewed. The inclusion criterion was diagnosis of discoid meniscus on MRI. Exclusion criteria were torn discoid meniscus at presentation, previous meniscal surgery and confounding knee conditions. MRI features of discoid meniscus collected were craniocaudal dimension, transverse dimension, transverse dimension to tibial plateau (TV:TP) ratio and increased intrameniscal signal. The clinical course was reviewed for knee pain, mechanical symptoms and treatment type.

RESULTS

Two hundred and nineteen of 3,277 (6.7%) patients had discoid meniscus. Of the 219 patients, 71 (32.4%) satisfied inclusion criteria. Seven patients had discoid meniscus of both knees resulting in 78 discoid menisci. The average patient age was 11.1 years (min: 2.0, max: 17.0). The average follow-up was 30.6 months. Of the 78 discoid menisci, 14 (17.9%) required surgery. Increased intrameniscal signal was found more in discoid meniscus requiring surgery (surgical: 10/14, nonsurgical: 19/64, P=0.009). Surgically treated discoid meniscus had a statistically significant increase in transverse dimension (surgical: 18.3±5.0 mm, nonsurgical: 15.7±4.3 mm, P=0.045) and TV:TP ratio (surgical: 0.55±0.15, nonsurgical: 0.47±0.12, P=0.036). Mechanical symptoms (surgical: 9/11, nonsurgical: 21/60, P=8.4×10^-6) and pain ≥1 month (surgical: 11/11, nonsurgical: 17/60, P=0.006) were found more often in surgical patients. Clinical and imaging criteria of mechanical symptoms and knee pain ≥1 month and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than 0.47 identified discoid menisci that developed a tear and/or required surgery with a sensitivity of 0.86 and specificity of 0.88.

CONCLUSION

Mechanical symptoms and knee pain ≥1 month, and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than or equal to 0.47, identified discoid menisci that would go on to tear and/or require surgery with a sensitivity and specificity of 0.86 and 0.88, respectively.

Automatic Discoid Lateral Meniscus Diagnosis from Radiographs Based on Image Processing Tools and Machine Learning

The aim of the present study is to build a software implementation of a previous study and to diagnose discoid lateral menisci on knee joint radiograph images. A total of 160 images from normal individuals and patients who were diagnosed with discoid lateral menisci were included. Our software implementation includes two parts: preprocessing and measurement. In the first phase, the whole radiograph image was analyzed to obtain basic information about the patient. Machine learning was used to segment the knee joint from the original radiograph image. Image enhancement and denoising tools were used to strengthen the image and remove noise. In the second phase, edge detection was used to quantify important features in the image. A specific algorithm was designed to build a model of the knee joint and measure the parameters. Of the test images, 99.65% were segmented correctly. Furthermore, 97.5% of the tested images were segmented correctly and their parameters were measured successfully. There was no significant difference between manual and automatic measurements in the discoid (P=0.28) and control groups (P=0.15). The mean and standard deviations of the ratio of lateral joint space distance to the height of the lateral tibial spine were compared with the results of manual measurement. The software performed well on raw radiographs, showing a satisfying success rate and robustness. Thus, it is possible to diagnose discoid lateral menisci on radiographs with the help of radiograph-image-analyzing software (BM3D, etc.) and artificial intelligence-related tools (YOLOv3). The results of this study can help build a joint database that contains data from patients and thus can play a role in the diagnosis of discoid lateral menisci and other knee joint diseases in the future.

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.

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.

A new method to diagnose discoid lateral menisci on radiographs

PURPOSE

The aim of this study was to prove that it is feasible to diagnose discoid lateral meniscus in radiographs. Plain radiographic findings of discoid lateral menisci with matched controls were analysed and compared in a quantitative method.

METHODS

Sixty consecutive patients (60 knees) who were diagnosed with discoid lateral meniscus (discoid group) by magnetic resonance imaging (MRI) were included. Another 60 age- and sex-matched controls with normal medial and lateral menisci on the basis of MRI findings were included as the control group. Each plain radiograph was evaluated from the anteroposterior view for the following variables: height of the fibular head (HFH), lateral joint space distance (LJSD), height of the lateral tibial spine (HLTS), obliquity of the lateral tibial plateau, obliquity of the lateral femoral condyle, distance from the lateral tibial spine to the lateral femoral condyle, height of the medial tibial spine, chordal distance of the femoral condyle (CDLF, CDMF), the HFH/LJSD, LJSD/HLTS and the CDLF/CDMF.

RESULTS

A significant difference was found in the HFH, LJSD, HLTS, DLC, CDLF, HFH/LJSD and LJSD/HLTS between the two groups. The cut-off values of the HFH, LJSD, HLTS, DLC, CDLF, HFH/LJSD and LJSD/HLTS were 12.9 mm, 6.6 mm, 7.8 mm, 3.0 mm, 2.7 mm, 2.0 and 0.9, respectively. Among the cut-off values in diagnosing discoid lateral meniscus, the sensitivity, specificity and ROC curve area of LJSD/HLTS were as high as 73.6 %, 83.0 % and 0.8, respectively. The corresponding values of the HFH/LJSD were as high as 66.0 %, 86.8 % and 0.8. For the first two indicators, the results of the HFH/LJSD and LJSD/HLTS were higher than that of most other parameters. At the same time, the ROC curve area of the HFH/LJSD and LJSD/HLTS ranked highest among all the results.

CONCLUSION

There were significant differences in the HFH, LJSD, HLTS, DLC, CDLF, HFH/LJSD and LJSD/HLTS, especially the HFH/LJSD and the LJSD/HLTS, between plain radiographic findings of discoid lateral meniscus patients and normal controls. The results of the HFH/LJSD and the LJSD/HLTS showed a positive impact on the diagnosis of discoid lateral meniscus in this research. These findings enable radiographs to screen for discoid lateral meniscus.

LEVEL OF EVIDENCE

II.

Symptoms of discoid lateral menisci

PURPOSE

This study aims to determine the symptoms of the patients with discoid lateral meniscus.

METHODS

We prospectively collected cases of the knees with discoid lateral meniscus. Twenty patients (7 female, 13 male) admitted between January 2012 and February 2014 were enrolled in this study. The mean age of the patients was 34 years (range 28-40).

RESULTS

The identified symptoms of a discoid lateral meniscus were "pain, stiffness, popping of the knee, feeling that the knee is "giving way", inability to fully extend (straighten) the knee". Thirteen patients (65%) had pain, 11 (55%) had popping of the knee, 4 (20%) had stiffness, 2 (10%) had "giving way" feeling, and 1 (5%) had inability to fully extend the knee. These symptoms did not prevent any patient's daily activities. No patients required surgical treatment.

CONCLUSIONS

Pain and popping of the knee were the most common symptoms in patients with a discoid lateral meniscus. The other symptoms were stiffness, feeling that the knee is "giving way", and inability to fully extend the knee, respectively. No symptoms had been required surgical treatment.