Knee Conditions Click on any of the conditions below to find out more. Meniscal Tear A meniscal tear will often be painful in the early stages and may cause a catching or clicking sensation. Cartilage damage Damage to the joint cartilage can cause a catching or clicking sensation and is often associated with knee swelling. Anterior cruciate ligament (ACL) tears An ACL tear is often painful and causes a swollen and stiff knee for the first few days. Kneecap (patella) dislocation and instability You knee is usually painful and your will be stiff and swollen. Knee osteoarthritis Osteoarthritis develops through wear and tear on the knee joint over the years. Medial collateral ligament (MCL) tears Often painful and can cause a stiff knee that feels unsteady in the first few days. Posterior cruciate ligament (PCL) tears Most people feel the knee give way and buckle beneath them. It is common to feel or hear a ‘pop’.