Knee pain is an extremely common complaint and the mostly reported causes include Osteoarthritis, Ligament Injuries, Meniscal Tear and Tendonitis.

Knee Osteoarthritis typically affects those over 50 years of age. It is more common in overweight people, and weight loss tends to reduce the symptoms. Family history and previous trauma (e.g. meniscus tears, ligament injury, and fractures to the bone around the joint) can contribute to the development of the condition. The most common symptoms include pain with activities, limited range of motion, stiffness of the knee, swelling of the joint, tenderness along the joint, feeling of “giving out” of the joint, and joint deformity (knock-knees or bow-legs). Medications and Physiotherapy are effective in controlling the symptoms. For more serious condition, where cartilage at the knee joint is massively destructed and inflammation does not subside, Total Knee Replacement Surgery may be indicated.

Anterior Cruciate Ligament (ACL) Injury is the most common type of knee ligament injuries. The ACL is the primary restraint to forward motion of the shin bone (tibia). The ACL also contributes stability to other movements at the joint including the angulation and rotation at the knee joint. When an ACL injury occurs, one may experience a sudden giving way of the knee, hearing a 'pop' at the time of injury, a sudden swelling of the knee joint and having knee pain during walking. One may be able to function in their normal daily activities without a normal ACL, but the resulting instability can make sudden and pivoting movements of the knee difficult, and it may make the knee more prone to developing Osteoarthritis and Meniscal Tear. For returning to the pre-injury activity level, Arthroscopic Surgery is usually the option.

Meniscal Tear is another common cause of knee pain. There are two tough cartilage (the menisci) in the knee which rest on the inside (medial meniscus) and the outside (lateral meniscus) of the joint. The meniscus is C-shaped and has a wedged profile. The wedged profile maintains the stability of the knee by keeping the rounded femur surface (i.e. top of the joint) from sliding off the flat tibial surface (i.e. bottom of the joint). The meniscus is nourished by small blood vessels, but the meniscus also has a large area in the center of that has no direct blood supply which tend not to heal. When meniscus tear occurs, usually due to trauma (when the knee is bent and then twisted) or degeneration, one can experience pain and swelling in the joint, also hearing clicking and feeling limitation of motion during movement. Many people live normal lives despite having a meniscus tear, however, when symptoms are irritable and interferes with activities, surgical repair should be considered.

Patella Tendonitis, or Jumper's Knee, is also an usual complaint of the knee. The patellar tendon connects the kneecap (the patella) to the shin bone. This is part of the 'extensor mechanism' of the knee, and together with the quadriceps muscle and the quadriceps tendon, these structures allow your knee to straighten out, and provide strength for this motion. Patellar tendonitis occurs when the tendon and the tissues that surround it become inflamed and irritated. This is usually due to overuse, especially from jumping activities. Those who have developed chronic patellar tendonitis of more than a year may require surgical intervention for pain relief.

It is not uncommon to see co-existing knee injuries, for instance, meniscal tear tends to occur along with injuries to the ACL and the medial collateral ligament (MCL). Making of an accurate diagnosis is important for finding all the sources of symptoms and directing an appropriate treatment at the cause.