The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
In Chinese Medicine knee weakness can be treated by two herbs that we have on record. Here is the list below.
Because it is a herb specifically indicated to treat knee weakness as can be seen on Desert-Living Cistanche's page.
Desert-Living Cistanches is a Warm herb that tastes Salty and Sweet. It targets the Kidney and the Large intestine.
Its main actions are: Tonifies Kidney Yang, Restores Essence and Blood. Induces laxation.
Because it is a herb specifically indicated to treat knee weakness as can be seen on Eucommia Leaf's page.
Eucommia Leaves is a Warm herb that tastes Pungent. It targets the Kidney and the Liver.
Its main actions are: Strengthens the Liver and the Kidneys
Impotence Infertility Lower back pain Lower back weakness Knee pain Constipation Frequent urination Tinnitus Vertigo Sore lower back