Can you walk if you have a meniscus tear? can you have the feeling of knee instability or your knee giving out with a knee sprain? i have l knee instability and pain on the outside of my knee?

See orthopedic surgeon and consider MRI. Do not try to tough through as walking on a knee injury can make it far worse. Your doctor will recommend the most appropriate approach

Most people can walk with a meniscus tear. Large meniscus tears can cause your knee to lock, catch, and make it difficult to fully extend. Knee sprains (ligament injury) can cause instability and pain. I would seen an orthopedic surgeon for evaluation.