Related Experiment Video
Updated: Jul 15, 2025
Software-Assisted Quantitative Measurement of Osteoarthritic Subchondral Bone Thickness
Published on: March 18, 2022
Age-based comparison of meniscal dimensions between an asymptomatic complete discoid lateral meniscus and normal
Yusuke Hashimoto1, Kazuya Nishino2, Takuya Kinoshita3
1Department of Orthopaedic Surgery, Osaka Metropolitan University, Graduate School of Medicine, Osaka, Japan. hussyyomu@omu.ac.jp.
Introduction:
This study aimed to evaluate the meniscal size of asymptomatic discoid lateral meniscus (DLM) and compare it with that of normal lateral meniscus (LM) and to compare changes in meniscal dimensions with age among patients with asymptomatic DLM and those with normal LM using magnetic resonance imaging (MRI).
Materials And Methods:
We retrospectively reviewed the medical records, including MRI data, of patients with asymptomatic DLM (DLM group) or normal LM (control group). Width and extrusion of both DLM and normal LM and tibial length were measured and compared using mid-coronal and mid-sagittal MR images. Meniscal size and sagittal and coronal meniscal ratio according to age, as well as differences between DLM and normal menisci, were also evaluated.
Results:
Thirty-four knees were included in the DLM group, whereas the control group comprised of 50 patients. The DLM group showed significantly less meniscal extrusion, greater coronal width, posterior capsule distance, sagittal meniscal length, and sagittal meniscal ratio than the control group (DLM: 0.1 ± 0.3 mm, 23.3 ± 2.2 mm, 5.4 ± 2.4 mm, 25.1 ± 2.8 mm, 61 ± 6%, and control: 0.4 ± 0.4 mm, 9.5 ± 2.3 mm, 2.5 ± 1.2 mm, 30.2 ± 2.6 mm, 71 ± 4%, respectively). The coronal meniscal ratio decreased with age in both the control (p = 0.001) and DLM (p = 0.037) groups. The sagittal meniscal ratio (p = 0.001) and minimum height (p = 0.04) decreased and the anterior capsule distance (p = 0.035), posterior capsule distance (p = 0.026), and entire sagittal length (p = 0.005) increased with age in the DLM group, while the distance between the meniscal inner margins (p = 0.019) increased with age in the control group.
Conclusions:
The meniscal ratio in the sagittal plane of the DLM group was significantly lower than that of the control group. The sagittal meniscal ratio of asymptomatic DLM decreased with age, indicating that the size of asymptomatic DLM does not change with age.
Level Of Evidence:
III: Retrospective comparative study.
Insights
Asymptomatic discoid lateral meniscus (DLM) is wider and longer but has a lower sagittal ratio than normal lateral meniscus (LM). DLM size does not change with age, though its sagittal ratio decreases.
Area of Science:
- Orthopedic Surgery
- Radiology
- Anatomy
Background:
- Discoid lateral meniscus (DLM) is an anatomical variation of the knee meniscus.
- Asymptomatic DLM requires evaluation to understand its meniscal dimensions and age-related changes.
- Comparison with normal lateral meniscus (LM) is crucial for characterizing DLM.
Purpose of the Study:
- To evaluate and compare the meniscal size of asymptomatic discoid lateral meniscus (DLM) with normal lateral meniscus (LM).
- To compare age-related changes in meniscal dimensions between DLM and normal LM using magnetic resonance imaging (MRI).
Main Methods:
- Retrospective review of MRI data from patients with asymptomatic DLM (DLM group) and normal LM (control group).
- Measurement of meniscal width, extrusion, posterior capsule distance, sagittal length, and meniscal ratios (coronal and sagittal) from mid-coronal and mid-sagittal MR images.
- Comparative analysis of meniscal dimensions and age-related changes between the DLM and control groups.
Main Results:
- The DLM group exhibited significantly less meniscal extrusion, greater coronal width, posterior capsule distance, sagittal meniscal length, and sagittal meniscal ratio compared to the control group.
- The coronal meniscal ratio decreased with age in both groups.
- In the DLM group, the sagittal meniscal ratio and minimum height decreased with age, while anterior and posterior capsule distances and entire sagittal length increased.
Conclusions:
- The sagittal meniscal ratio of asymptomatic DLM is significantly lower than that of normal LM.
- While the sagittal meniscal ratio of asymptomatic DLM decreases with age, the overall size of asymptomatic DLM does not appear to change with aging.
