Your knee comprises a complex intersection of bones, muscles, joints and tendons. As such it's vulnerable to many syndromes and diseases.
Most commonly, orthopedic doctors treat arthritis in elderly patients. Arthritis comes in three different forms:
- Osteoarthritis. Also called degenerative arthritis, this disease starts with inflammation in the joints that leads to breakdown and loss of cartilage.
- Rheumatoid arthritis (RA). RA is an autoimmune disease causing chronic inflammation to the joints and eventual deterioration and deformity.
- Post-traumatic arthritis. This type of joint wear and tear comes as a direct result of physical injury or trauma to the cartilage or bone.
The most common symptoms of arthritis are pain, stiffness and swelling, which often worsen after activity. Many people experience a locking of the knee or an inability to move the knee at all. They may also experience a buckling effect where their knee joint collapses, putting them at risk of falling. Patellofemoral pain syndrome affects the kneecap and causes the cartilage to weaken and wear thin. The most obvious symptoms of patellofemoral arthritis are pain and an audible cracking in the knee.
Kneecap bursitis, or prepatellar bursitis, cause the fluid-filled sac in the kneecap, the bursa, to become swollen and inflamed. This can occur because of rheumatoid arthritis, gout, kneeling a great deal and landing directly on your knee when falling, as happens in sports. With bursitis, your knee will appear swollen and warm, and you'll often experience pain during activity.
Many athletes suffer from runner's knee, which causes pain in the front of the knee due to an increase in activity. Often with this condition, your kneecap is often out of alignment, strained, injured, dislocated or weak. You'll experience an achy sensation in the kneecap.
Osgood-Schlatter disease is a common injury among older children and teens that occurs due to swelling and tenderness where your large tendon under the kneecap attaches to your shinbone.