Assessment of discoid meniscus injury using solid-state nuclear magnetic resonance (SSNMR)

Lateral discoid meniscus (LDM) injuries have traditionally been diagnosed using magnetic resonance imaging (MRI), which provides detailed macroscopic visualization of the meniscus. MRI remains the gold standard for evaluating meniscal morphology and tears, allowing for differentiation between complete and incomplete discoid meniscus types. However, while MRI effectively identifies macroscopic alterations such as meniscal thickening, hypermobility, and tears, it may not always detect the early degenerative changes at the same molecular resolution.

This study explores the potential of solid-state nuclear magnetic resonance (SSNMR) in diagnosing adult LDM injuries.

The study involved 80 adult participants, divided into two groups: 40 individuals with LDM injuries (experimental group) and 40 healthy controls. SSNMR assessed meniscal integrity by Chemical Shift Anisotropy, dipolar coupling strength, and T1 and T2 relaxation times. MRI assessed morphological changes such as free edge height and body width. Independent sample t-tests were applied for statistical comparison, and effect sizes (Cohen's d) were calculated to determine the practical significance.

The injured menisci showed higher Chemical Shift Anisotropy (75.2 ± 4.1 ppm vs. 60.3 ± 3.8 ppm, p < 0.001, Cohen's d = 1.50) and dipolar coupling strength (8.4 ± 1.1 kHz vs. 5.2 ± 0.9 kHz, p < 0.001, Cohen's d = 1.25), indicating collagen degradation. T1 (710 ± 50 ms vs. 530 ± 40 ms, p < 0.001, Cohen's d = 1.65) and T2 (48 ± 3.4 ms vs. 32 ± 2.1 ms, p < 0.001, Cohen's d = 1.58) relaxation times were also significantly prolonged in the injured group, reflecting altered hydration. Morphologically, the injured group had higher free edge height (5.39 ± 0.71 mm vs. 1.69 ± 0.30 mm, p < 0.001, Cohen's d = 2.0) and body width (31.1 ± 3.16 mm vs. 2.39 ± 0.31 mm, p < 0.001, Cohen's d = 1.8). Capsular edge height was significantly lower (4.09 ± 0.33 mm vs. 5.11 ± 0.59 mm, p < 0.001, Cohen's d = 1.3). The fat angle sign was higher (65% vs. 0%, p < 0.001), and the wedge sign was lower (10% vs. 72.5%, p < 0.001).

SSNMR offers a novel approach and underscores the potential of SSNMR in orthopedic imaging, facilitating improved precision in early diagnosis and treatment planning.