Knee

A 'pop' in the knee on a downhill walk: a radial meniscus tear and arthroscopic repair

Hee Seung Nam, MD, Orthopedic Surgeon · October 28, 2026

Many people hurt a knee unexpectedly while walking or hiking and come to the hospital. Today I introduce a case of a 'radial tear of the meniscus' for which surgery is actively considered.

Patient case and diagnosis

He is a 54-year-old man. He twisted his knee going downhill, felt a 'pop' with severe pain, and came in. The pain continued afterward and he could not walk normally.

The McMurray test, which checks for a meniscus injury, was clearly positive and the pain was severe, so I took an MRI right away to confirm the exact cause.

MRI findings

MRI confirmed a radial tear of the meniscus. The meniscus of the knee spreads body weight and absorbs shock. Its fibers are arranged in a circular direction and resist the pressure on the knee (hoop tension); a radial tear splits across these fibers.

It is like a rubber band that has snapped, and if left alone the meniscus can lose its shock-absorbing function. It is known to have a worse outlook than other tear patterns and can bring on degenerative arthritis early even at a young age, so where possible I consider restoring it by repair.

The arthroscopic procedure

Looking inside the knee with the arthroscope, the radial tear, in which the meniscus was split from the inside toward the outside, was clear, just as on MRI. A split meniscus must be fixed firmly back in place to regain its original function.

After bringing the opened edges together precisely, I sutured them with a double-arm needle. I focused on restoring the anatomy so that the torn meniscal fibers could regain their original tension.

Rehab after surgery

In a radial tear the repaired site is under a lot of force from body weight trying to pull it open again. That is why care in the first 4 to 6 weeks is especially important. What follows is a general example and can vary with the tear pattern and surgical method.

• Up to 4 weeks after surgery (protection and healing): wear a knee brace and walk on crutches without putting the foot down. The angle of knee bending is also usually limited to within 90 degrees so as not to stress the repair.
• 4 to 6 weeks (partial weight bearing): with the brace on, begin practicing putting weight on the foot gradually, starting from the toes, and increase the bending angle little by little.
• After 6 weeks (full weight bearing and strengthening): remove the brace and crutches and practice normal walking. Build up the thigh muscle weakened after surgery (the quadriceps) with a stationary bike and light strengthening. Serious exercise such as jogging or hiking is tried in stages, usually after 3 to 6 months depending on recovery.

In closing

A damaged meniscus often has trouble healing on its own. A radial tear in particular can lead to rapid progression of arthritis if left, so treatment that saves the original meniscus wherever possible is important.

If the pain does not settle after a 'pop' in the knee, I recommend seeing an orthopedist without delay. If you have questions, please write to doctornhs@naver.com.

This article is general information. Surgical results and recovery time differ from person to person with the tear pattern, age and activity level, and the treatment method must be decided through an examination.