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Five key ultrasound findings associated with medial meniscus posterior root tear
Manase Nishimura1, Yasushi Takata1, Yosuke Shima2
1Department of Orthopedic Surgery, Graduate School of Medical Sciences, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.
Purpose:
Medial meniscus posterior root tear (MMPRT) is a critical condition leading to knee osteoarthritis. Although MRI is the standard diagnostic tool, its availability and cost can be limiting. This study aimed to identify characteristic ultrasound (US) findings of MMPRT and determine the criteria for recommending MRI.
Methods:
This multicenter prospective study included 100 patients (101 knees, mean age 58.3 ± 11.2 years, 58 males and 42 females) with medial knee joint pain. All patients underwent US and MRI evaluations. US findings included joint effusion, synovial hypertrophy, and medial meniscus extrusion (MME) in the supine, 90° flexion, and standing positions. Color Doppler evaluation of Doppler signals (DSs) in the bursa and through the femur and tibia were performed. Statistical analysis compared US findings between MMPRT and non-MMPRT groups.
Results:
The MMPRT group showed significantly higher rates of joint effusion (p = 0.028) and increased MME in all positions (p < 0.001). MME changed from 0° to 90° knee flexion (p = 0.003). Color Doppler evaluations revealed DSs through the femur (p = 0.008) and tibia (p = 0.013). Horizontal meniscal tears were more frequent in the non-MMPRT group (p < 0.001). For three or more positive parameters, sensitivity and specificity were 80% and 82.7%, respectively.
Conclusion:
Five key US findings-joint effusion, increased MME, smaller MME change in knee flexion, fewer horizontal meniscal tears, and increased DSs through the femur and tibia-are characteristic of MMPRT. These suggest that US can effectively identify patients requiring MRI, facilitating early management.
Insights
Ultrasound (US) can identify medial meniscus posterior root tears (MMPRT) by detecting joint effusion, medial meniscus extrusion (MME), and Doppler signals. These US findings help determine which patients with knee pain need further MRI evaluation for MMPRT.
Area of Science:
- Orthopedics
- Radiology
- Sports Medicine
Background:
- Medial meniscus posterior root tears (MMPRT) are a significant cause of knee osteoarthritis.
- Magnetic Resonance Imaging (MRI) is the gold standard for diagnosing MMPRT but has limitations in availability and cost.
Purpose of the Study:
- To identify characteristic ultrasound (US) findings associated with MMPRT.
- To establish criteria using US to recommend MRI for suspected MMPRT.
Main Methods:
- A multicenter prospective study involving 100 patients with medial knee pain.
- All patients underwent both US and MRI evaluations.
- US assessment included joint effusion, synovial hypertrophy, medial meniscus extrusion (MME) in various positions, and Color Doppler evaluation for Doppler signals (DSs).
Main Results:
- MMPRT group showed significantly higher rates of joint effusion and increased MME across all positions (p < 0.001).
- Changes in MME with knee flexion and increased DSs through the femur and tibia were significant indicators of MMPRT (p < 0.013).
- A combination of three or more US parameters demonstrated 80% sensitivity and 82.7% specificity for MMPRT detection.
Conclusions:
- Key US findings for MMPRT include joint effusion, increased MME, minimal MME change with flexion, fewer horizontal meniscal tears, and increased femur/tibia DSs.
- Ultrasound can effectively identify patients who would benefit from MRI for MMPRT.
- This approach facilitates earlier diagnosis and management of MMPRT, potentially preventing further knee damage.
