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🏥 Gotokuji Orthopedic Clinic / Patient Guide

Medial Meniscus Posterior Root Tear

MMPRT
Pain behind the inner knee — a tear at the "root" of the meniscus

The meniscus is a C-shaped cushion between the thighbone and shinbone inside the knee.
MMPRT occurs when the "root" (attachment point) of the medial meniscus tears away from the bone.
When the root tears, the meniscus loses its ring-like tension (hoop stress), and its cushioning function drops significantly.

1
The meniscus weakens with age

Over time, meniscal tissue degenerates and becomes more fragile

2
Load concentrates on the inner knee

Bow-legs and excess weight place chronic stress on the medial compartment

3
Squatting and rising stress the root

Deep squats and standing up put significant force on the posterior root

4
The root tears and cushioning is lost

The meniscus slips out of position and extrudes beyond the joint (meniscal extrusion), leaving cartilage exposed to direct load

👴 Aging 🦿 Bow-legs ⚖️ High BMI 🧎 Frequent squatting
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Pain behind the knee or inner-posterior area
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A "pop" or "crack" sound before pain started
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Worse when going downstairs or standing up
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Pain when squatting deeply
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Knee swelling and limited range of motion
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Activity Modification
Avoid deep squatting and high-impact activities to reduce knee stress
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Weight Management
Even a few kilograms of weight loss may help reduce the load on the inner knee
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Muscle Strengthening
Build quadriceps and hip abductor muscles to protect the knee
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Hyaluronic Acid Injection
Injected into the joint to improve lubrication and relieve pain
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Bracing & Insoles
Distribute load away from the damaged area with supports and insoles
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Surgery (Root Repair)
Arthroscopic posterior root repair if pain persists despite conservative care. We do not perform surgery here, so we refer you to a partner hospital
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Early management is key to protecting your knee's future

Conservative treatment may relieve pain, but full recovery of meniscal function can be difficult. If left untreated, the progression to osteoarthritis may accelerate. Treatment choice is based on a comprehensive evaluation of age, activity level, and cartilage condition.

💡 Tips for Daily Life

  • Focus on weight management — even a small amount of weight loss helps reduce the load on the knee
  • Move from the hips, not the knees — avoid letting knees collapse inward
  • Use handrails on stairs and take small steps
  • If you have pain behind the knee, don't self-diagnose — see a specialist early