Moderate to severe pain behind knee joint is a leading cause of disability in middle-aged to elderly population since knee is the primary weight bearing joint of the body that is responsible for locomotion. Although, mild and occasional knee pain is fairly common among individuals of all age groups, the cause of chronic and moderately severe pain behind knee joint in young adults is caused by excessive physical activity and overuse of knee joint that may lead to inflammation, discomfort and limitation of physical independence.

Causes of Pain Behind Knee

Few common causes of pain behind knee joint are:

1. Arthritis

Arthritis (also known as inflammation of the joint surfaces) is marked by redness, swelling, fever or local warmth and moderately severe pain that aggravates after physical activity. There are different varieties of arthritis (infectious causes are mostly due to local trauma or invasion of microorganisms from blood stream leading to septic arthritis). Other varieties of arthritis that may produce pain behind knee joint are rheumatoid arthritis and osteoarthritis (that produce symptomatic pain and limitation of movement due to wear and tear changes of articular cartilage).

2. Ligament injury

Physically active individuals and athletes often develop severe pain and discomfort behind the knee due to injury, tearing or sprain of the primary ligamentous support of the knee joint. The most common ligaments that suffer trauma due to overuse or in appropriate use of knee are ACL (Anterior Cruciate Ligament), MCL (medical collateral ligament), and PCL (Posterior Cruciate Ligament). Depending upon the severity of injury and associated symptoms, the treatment may be conservative or surgical.

3. Patellar Tendonitis

Inflammation of patellar tendon can lead to patellar tendonitis that is most common in athletes who perform vigorous physical activity without proper warm-up exercises. It is also known as Jumper’s knee (most common in athletes who perform long jumps or overuse of muscles and tendons of knee joint).

4. Meniscal Tear

Medial or lateral meniscal injury (knee cartilage) is often a consequence of sports related injury that may lead to moderately severe pain behind the knee joint. It is also reported in severe degenerative diseases of bones.

5. Baker’s Cyst

Baker’s cyst derived its name from the occupational injury caused by excessive pressure and stress in the popliteal fossa that leads to accumulation of fluid behind the knee. It is more common in elderly individuals and may mimic a malignancy in some situations.

6. Deep Vein Thrombosis

Deep vein thrombosis is reported frequently in individuals who have protein C or S deficiency, chronic history of coagulopathy or immobilization, recent surgery or other similar hypercoagulable state that leads to formation of thrombus in the deep veins of the legs. Symptoms of pain and discomfort behind the knee and along the legs (or thighs) is associated with ischemia produced by activity and lack of oxygen supply due to partial or complete occlusion of blood supply.

7. Overweight and Overexertion

Obesity (or body mass index over 28 kg/ m2) leads to degenerative changes in the connective tissue component of the knee joint. Weight reduction is an ideal remedy in all such cases.

Overexertion of tissues (muscles, tendons and ligaments or other components of connective tissue) is another leading cause of pan behind knee joint.

8. Others

Other common causes include fracture or dislocation of knee joint or other aligning bones (tibia and fibula) that may produces swelling, redness and severe pain that aggravates after minor activity or movement. Fracture may be traumatic or pathological (in case of weak bones due to mineral deficiency, malignancy or chronic steroid use). In addition, weakness of leg muscles due to overuse, chronic inflammation and endocrinological disorders may also lead to pain behind knee joint. Lastly, aging process is also responsible for pain and discomfort due to malnutrition and other causes.

Complications of Pain Behind Knee

Complications of untreated or poorly managed pain behind the knee joint are immense. A few common ones are listed below:

• Difficulty in maintaining normal day to day activities due to limited mobility
• Stiffness and limited range of motion that may deteriorate over time
• Discoloration of overlying skin
• Hypersensitivity or soreness of skin that may involve entire lower limb
• Swelling, pain, edema and weakness

Remedies for Pain Behind Knee

In almost 70 to 90% cases, moderate knee pain (or pain behind knee joint) responds very well to home remedies and lifestyle modifications. A few proven remedies are discussed below:

1. Knee Braces

Although rest and limited mobility help in optimal healing of the affected knee; however, in order to stabilize your knee joint without affecting your day to day activities, it is highly recommended to use knee braces that helps in stabilizing ligaments and connective tissue; thereby reducing the stress and strain symptoms.

2. Stretching Exercises

Low impact and low frequency exercises promote blood flow to the healing knee joint and also promote conditioning of knee muscles and connective tissue. However, caution must be maintained, not to overexert the joint or delicate tissues. Strengthening and stabilizing exercises prevent recurrence of symptoms in future and also improve athletic endurance.

3. Special Shoes

Often times, wrong choice of footwear also exert pressure on the knee joint and lead to degenerative changes in the connective tissue and articular tissues of the lower limb. Use of right size and right type of shoes helps in decreasing the stress and strain on your tissues.

4. OTC Drugs

Over the counter pain- killers like non-steroidal anti-inflammatory drugs are overly helpful in decreasing the pain symptoms. However, in the absence of a clear reason, it is recommended to avoid blood thinners or other anti-inflammatory medications without seeking help from your primary physician.

5. Lose Weight

Obesity or being over-weight increase the stress and pressure on your lower limbs and delays healing. Additionally, wear and tear changes are more aggressive in obese individuals that further increases bone destruction and damage to articular cartilage.

6. Surgery

In certain conditions (when the cause of pain behind knee is an organic, infectious, cystic or inflammatory lesion), surgical manipulation is needed. The choice of procedure is dependent upon the extent of bone involvement and residual bone damage.