A patient who has been experiencing severe pain in his left knee for the past few weeks has consulted British doctor Ellie Cannon. He had already been to the doctor, who diagnosed the so-called Baker's cyst, although it is not certain that this is the cause.
Baker's cyst quite often causes pain and swelling in the knees. As a rule, this popliteal hernia appears as a result of an injury or arthritis. Patients often complain of pressure and discomfort after walking or other physical activity. If this cyst ruptures, you will feel very sharp pain and even hear a pop. In addition, the knee may look red, swollen, and very hot to the touch.
But there are other more serious conditions that can be mistaken for a Baker's cyst. For example, a blood clot, so it is very important to exclude them. Your GP or GP may send you for an ultrasound, which usually answers all your questions. For example, if the pain appeared after playing intense sports like football or playing tennis, then we can talk about a disorder called tennis leg – an incomplete or complete rupture of the calf muscle.
Again, ultrasound will help make the correct diagnosis. Other possible problems include tears or sprains in the knee muscles. Most conditions are treated conservatively with rest, ice packs, or pain relievers. (READ MORE) 
Ellie Cannon Medical Staff consulting physician for Mail on Sunday and Mailonline