I'm sorry to hear you're experiencing pain, itching, and numbness in your left thigh along with knee pain. These symptoms can arise from several possible causes, including nerve irritation or compression (such as from a herniated disc or sciatica), circulation issues, or joint problems like osteoarthritis.

The knee pain and joint discomfort might be related to osteoarthritis, a condition where the cartilage protecting the ends of bones wears down, causing pain and stiffness. A medication like Lubrijoint OD Tablet, which contains glucosamine, is sometimes used to help reduce joint pain and improve flexibility by supporting cartilage repair.

However, the combination of numbness and itching suggests there might be nerve involvement, which requires careful evaluation. It would be important to see an orthopedic specialist or a neurologist who can perform a thorough physical examination, possibly including imaging studies, to determine the exact cause and recommend appropriate treatment.

If symptoms worsen or you experience weakness, severe pain, or loss of function, please seek medical attention promptly. For now, avoid activities that exacerbate your symptoms and consider consulting a specialist for a detailed assessment.To narrow down potential causes, we will need some more information.Please tell me your age and gender.