Knee pain is a common complaint in modern society. Knee pain can be debilitating, and a source for concern. In general, there are two types of patients with knee problems, younger more active individuals, and older patients with worn out joints. This difference lies in the type of conditions that arise.

Younger patients tend to have problems with tendons and ligaments within and around the knee. They tend to be more heavily involved in contact sports, so they might also suffer from injuries which may cause torn ligaments, cartilage/meniscus injuries and dislocated joints. Heavy involvement in sport may also result in overuse or strained/torn tendons.

Elderly patients generally accumulate small injuries to their knees throughout life. This accumulates in a condition known as osteoarthritis of the knee, in which the joint cartilage over the knee surfaces gets worn out. They frequently have pain with everyday motions, such as prolonged walking or standing, may have problems with stairs or slopes and may be unable to squat.

What can cause pain in the knee?

Pain can arise in the knee from several sources, damage to any of the above areas can result in pain in the knee. Most common, pain in the knee is felt in front or inside the knee (anterior knee pain). Sometimes, especially with meniscus injuries or muscle injuries, patients may feel pain at the back of the knee (posterior knee pain).

In the early stages of knee problems, knee pain usually happens with activity only (mechanical), but as the conditions worsen, patients may start to experience knee pain even without knee movement or activity.

Parts of the knee which can cause pain include:

• Ligaments – There are 4 major ligaments which are commonly injured in the knee. These are the anterior and posterior cruciate ligaments (inside the knee) and the medial (inner portion) and lateral (outer portion) collateral ligaments which lie outside the knee joint proper.
• Cartilage – The joint surfaces of the knee are lined with a special type of tissue known as joint cartilage or hyaline cartilage. This is a very smooth material which reduces friction and allows the knee to move smoothly.
• Meniscus – Menisci (plural) are C-shaped pieces of a special type or cartilage known as fibrocartilage, which helps to cushion impact in the knee, and also helps to stabilize the knee.
• Muscles and tendons – There are several groups of muscles and tendons around the knee, which can get inflamed from overuse during sport.
• Bone – Sometimes the bone of the knee joints can become damaged, whether during sport, or as a side effect of cartilage damage, this can also result in knee pain. 

What are the other symptoms associated with knee pain?

Knee pain can be associated with a variety of other symptoms, including:

• Swelling of the knee. Swelling of the knee is one of the most common complaints, and can occur immediately after an injury or after several hours. It sometimes also occurs after prolonged use, and is a sign that something is wrong inside the knee.
• Clicking sounds in the knee, which is painful, may sometimes represent torn structures within the knee. This can include torn cartilage or meniscus. Painless clicking in the knee is also a common occurrence, but is otherwise harmless.
• Knee stiffness, or inability to fully straighten the knee sometimes happens in conjunction with knee swelling, but may occur alone. It usually indicates a serious underlying problem within the knee.
• A feeling of the knee giving way easily is another common complaint, especially amongst patients who have had ligament injuries to the knee. This is also common in patients with worn out joints due to muscle weakness arising from inactivity.
• Knee getting stuck in one position without being able to bend or straighten it is a condition known as locking, where the knee is locked in place. It is most commonly caused by meniscus tears.
• Loss of knee function is most apparent during activities such as stair climbing, slope walking, prolonged walking or squatting. Patients with knee problems may find it difficult or impossible to do these activities. 

Knee pain in younger patients

As mentioned previously, knee pain in younger patients tends to arise due to injuries especially those sustained during sport. Patients will often give a history of a twisting injury to the knee, typically while standing on one leg only. Another common occurrence is for the injured knee to be hit from the side while the patient is standing.

A variety of injuries can result from these mechanisms:

• Ligament injuries such as injuries to the anterior cruciate ligament, a vital ligament for knee stability can occur.
• Tears to the meniscus which may occur with or without ligament injury. In severe cases, it can cause locking as detailed previously.
• Cartilage injuries can also occur. This is sometimes also related to dislocations of the knee cap (patella).

Apart from injury, younger patients may also experience knee pain due to tendon overuse, which results in pain and swelling especially over the front of the knee. This most commonly affects the area above the kneecap, but can affect the area below it as well.

Knee pain in older patients

Age itself does not always mean that one will start to experience knee pain. However, age makes it more likely that your knee has sustained injuries throughout your life. As a result, older patients especially those above the age of 60 often suffer from worn out joints (knee osteoarthritis).

This is characterized by extensive loss of cartilage over the knee joint, and results in pain and stiffness. Many patients will find themselves losing knee function, and will have difficulty going up and down stairs. They usually also lose the ability to squat at an early stage, and learn mechanisms to cope. 

How will my knee pain be worked up?

Patients with knee pain will undergo a medical interview, and based on the information gained from the interview, patients will undergo a focused examination of the knee and the associated regions. This will provide the doctor with information pertaining to the underlying condition.

You may then be asked to undergo plain X-rays of the knee, and may also be asked to take standing X-rays of the leg to check leg alignment. In patients suspected of having ligament/meniscal damage, you may also be asked to go for an MRI scan.

How will my knee pain be treated?

Depending on the underlying condition, your treatment will be tailored for you. We provide a full suite of options to treat what ails you, be it surgical or non-surgical. In the knee these options include,

• Medications to manage knee pain
• Lifestyle modifications to help you cope with knee pain
• Knee bracing to protect and support your knee to help relieve pain and support function
• Knee physiotherapy for better function and movement
• Pain procedures and injections to relieve knee pain
• Ligament surgery to allow return to sport
• Keyhole knee surgery to repair meniscus and cartilage injuries
• Knee replacement solutions for patients with severe knee osteoarthritis

References:

Related Articles by Dr Yong Ren

• What is an anterior cruciate ligament (ACL) injury?
• What happens if I injure my Posterior Cruciate Ligament?
• What is a Meniscal Injury?
• What is a Long Bone Fracture?
• What are Tibial Plateau Fractures?