There is an expression that is so appropriate for fitness: move it or lose it. Well intentioned sports therapists or doctors sometimes recommend complete rest for an injury, and then more bad things happen. Nowadays, the advice is often to keep it moving.
The latest research on sprains has us up and about within 2 days beginning to gently use the injured area, allowing for a gradual progressive improvement in the joints ability to support weight or move without discomfort.[1]
The most common type of knee pain is caused by osteoarthritis or arthritis. Doctors recommend that you keep moving through both of these, as you want to maintain flexibility and mobility. Sometimes they will recommend a reduced range of motion to make the exercise manageable. With a reduced range of motion, you can still get an excellent workout – maybe even a better one. While working a smaller range, you can focus attention on better form. Take a simple plié for example. If you are working a big range of motion, you might be so focused on hitting the bottom of the movement and then getting all the way back to the top, that you don’t have time to focus on all the intricacies of form. Working the smaller range gives to time to ensure the hips are heavy on the way down, and that glutes are engaging on the way up, as well as inner things, and knee caps lifting. You might even get a better workout if you can really focus on the form.
Over time, an amazing thing can happen with a continued barre practice. You can develop muscles around the knee joint, strengthening both the front of the thigh (quadriceps) and the back of the thigh (hamstring), causing an overall reduction in knee paint. Similar things can happen around other joints.
Long story short, don’t count yourself out because of an injury. Check with your doctor and if they advise you to keep moving, we are here to help you!
[1] https://www.mayoclinic.org/diseases-conditions/sprains/diagnosis-treatment/drc-20377943