An observational study on MR images of the effect of the discoid meniscus on articular cartilage thickness

Dynamic effects of eifferent nail placement strategies on LenkeC scoliosis

BACKGROUND: Although the internal fixation technique for scoliosis is effective, there is a great risk of nail placement in actual operation. OBJECTIVE: To compare the effects of three different nail placement strategies on LenkeC patients with scoliosis under cyclic loading. METHODS: Firstly, the finite element model was established by using CT scanning images and X-ray images of patients with LenkeC scoliosis. Secondly, the validity of the model was verified. Finally, the harmonic response analysis and transient dynamic analysis were carried out. Results: The results showed that the maximum amplitude of each vertebral body appeared in the Z direction at the third natural frequency and the amplitudes of each corresponding vertebral body were very close under three kinds of nail placement. Under different nail placement methods, the uneven distribution of nails would make the model produce obvious stress concentration, but the principal stress of vertebral body and nail rod was far lower than its own yield strength. This showed that under the axial cyclic load, the vertebral bodies of scoliosis tended to have larger impact in Z direction. From the point of view of dynamics, it was feasible to reduce a certain number of nails in operation. CONCLUSION: This paper revealed that it was feasible to reduce a certain number of nails during surgery.

The Relationship Between Discoid Meniscus and Articular Cartilage Thickness: A Quantitative Observational Study With MRI

Background:

Several cadaveric imaging studies have demonstrated that the articular cartilage thickness on the tibial plateau varies depending on coverage by native meniscal tissue. These differences are thought to partially contribute to the rates of cartilage degeneration and development of osteoarthritis after meniscectomy. Because there is greater tibial plateau coverage with meniscal tissue in the setting of a discoid meniscus, these findings may also have implications for the long-term health of the knee after saucerization of a torn discoid meniscus.

Purpose:

To evaluate the relationship between lateral compartment articular cartilage thickness and the presence or absence of a discoid meniscus.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Included in the study were 25 patients younger than 40 years of age who had undergone a 1.5-T or 3-T knee magnetic resonance imaging (MRI) between 2010 and 2016 at a single institution and had an intact, lateral discoid meniscus. Only patients with an otherwise asymptomatic lateral compartment were included. The authors then identified 35 age-matched controls with a nondiscoid, intact lateral meniscus who underwent knee MRI at the same institution and during the same period. The articular cartilage thicknesses in 6 zones of the lateral femoral condyle (LFC) and lateral tibial plateau (LTP) were measured for each patient by 2 musculoskeletal radiologists, and the mean thicknesses were compared between the study and control groups.

Results:

The average age at MRI was 22.63 years (range, 8.30-35.90 years) for the discoid group and 20.93 years (range, 8.43-34.99 years) for the nondiscoid group. The nondiscoid group had significantly greater mean articular cartilage thickness in all 6 zones of the LTP (P < .05 for all). When comparing the zones of the LFC, there was no significant difference in the mean thickness in any zone between the 2 groups.

Conclusion:

Patients with discoid menisci had thinner baseline articular cartilage thickness in the LTP compared with those patients without discoid menisci.

Diagnostic Value of Ultrasound in Children with Discoid Lateral Meniscus Using Either an Intracavitary Convex Array Probe or a Linear Array Probe

This prospective study aimed to assess the usefulness of an intracavitary convex array probe (ICAP) in visualizing the lateral meniscus (LM) and improving the diagnostic utility of ultrasound (US) when diagnosing or screening for discoid lateral meniscus (DLM) in children. We included 105 knees (66 patients) that had symptomatic or asymptomatic DLM. We extracted and retrospectively reviewed data regarding patient demographics, medical records, magnetic resonance imaging (MRI), ultrasonographic features and arthroscopic findings. The inner edge of the LM visualized using an ICAP was significantly clearer than that visualized using a linear array probe, and the difference was significant (p < 0.01). The edges were better visualized in patients aged <8 y than in those aged >8 y, and the difference was significant (p < 0.001). The average widths of the LM body using an ICAP and MRI were 19.85 ± 3.63 and 24.46 ± 4.94 mm, respectively, and the wider the meniscal width, the greater was the deviation between the US and MRI measurements, which were positively correlated (r = 0.612, p < 0.001). With the use of MRI measurements and an ICAP, meniscal widths in poorly visualized LMs were greater than those in clearly visualized LMs, but this difference was not significant (p = 0.161). US scans using an ICAP and MRI were highly consistent in assessing the shape of the menisci (κ = 0.849, p < 0.001). US scan using an ICAP is a non-invasive, convenient and low-cost modality for diagnosing or screening for DLM in the pediatric population, especially in children aged <8 y.

Morphological Analysis of Normal Meniscus on Magnetic Resonance Imaging (MRI)-Based Three-Dimensional Reconstruction Models in Healthy Chinese Adults

Background

The purpose of this cross-sectional observational study was to determine the morphological meniscus characteristics in a normal Chinese population and assess possible relationships between demographic data and meniscal morphological parameters.

Material/Methods

We examined 116 menisci (58 lateral and 58 medial) from 29 healthy Chinese volunteers (10 men, 19 women, mean age 26 years [range, 20–33 years]) with MRI and three-dimensional reconstruction using Mimics software. The width, thickness, anteroposterior distance (APD), lateral-medial distance (LMD), and covering angle (CA) were measured on reconstructed models. Univariate analysis was used to evaluate the differences of morphological parameters between the medial and lateral menisci, between sides, and between males and females. Pearson correlation analysis was used to evaluate the correlation between meniscal morphological parameters and body height, weight, and body mass index (BMI).

Results

Univariate analysis demonstrated that the width, thickness, APD, LMD, and CA were significantly different between lateral and medial menisci. The LMD and APD of menisci in men were significantly larger than in women. There was no significant difference in meniscal thickness and CA between males and females. The lateral meniscus dimensions were slightly larger in the right knee. According to Pearson correlation analysis, the APDs of both lateral and medial menisci were strongly correlated with height and weight (lateral: r=0.596, r=0.500; medial: r=0.684, r=0.680).

Conclusions

The morphologies of medial and lateral menisci were different and were not significantly correlation with each other. The meniscal width and diameter were correlated with demographic data, but the thickness and CA did not significantly differ by sex, height, or BMI.