Knee pain is a symptom that can arise due to wear and tear on the joint, excess weight or sports injuries that can occur during a run or a game of soccer.

However, when knee pain prevents walking or worsens over time, it may be a sign of a more serious problem such as a ligament tear, osteoarthritis, or Baker’s cyst, which can be confirmed through imaging tests such as an X-ray or CT scan. 

The main causes of knee pain are:

1. Trauma Injury

Trauma injury to the knee can occur from a fall, contusion, blow, knee sprain or trauma, for example. In these cases, pain may arise throughout the knee or in specific regions according to the location of the injury.

What to do: in case of mild injuries, without fracture, you can rest or apply an ice pack 2 to 3 times a day for 15 minutes. However, in more serious cases, such as a fracture, seek medical help immediately to initiate appropriate treatment. Physical therapy is also recommended to aid in recovery and relieve pain, even in mild cases. 

2. Ligament rupture

Knee ligament rupture can occur from a sprain caused by a forceful blow or twisting of the knee during a sudden change of direction, for example. The type of pain usually indicates the ligament that was torn:

• Pain on the lateral side: may indicate injury to the anterior cruciate ligament, posterior cruciate ligament, or coronary ligament;
• Pain in the knee when straightening the leg: may indicate a rupture of the patellar ligament;
• Pain on the inside: may indicate injury to the medial collateral ligament;
• Pain deep, in the middle of the knee: may be rupture of the anterior or posterior cruciate ligament.

Generally, when the ligament rupture is mild, no specific treatment is necessary, but it should always be evaluated by a knee pain specialist or a physical therapist.

What to do: you can apply ice packs 3 to 4 times a day for 20 minutes for 3 to 4 days, as well as rest, use crutches to avoid overloading the knees, elevate the leg to avoid swelling, and use a knee brace on the affected joint. In more severe cases, it is important to consult a doctor, who may immobilize the knee with a splint for 4 to 6 weeks and, if necessary, indicate surgery. Learn about other treatment options for ruptured knee ligaments. 

3. Tendonitis

Tendonitis is an inflammation in a tendon of the knee and the type of pain varies with the location of the tendon:

• Pain in the front of the knee: indicates inflammation in the patellar tendon;
• Pain on the side of the knee: indicates inflammation in the iliotibial tendon;
• Pain on the inside of the knee: indicates inflammation in the tendons of the goosefoot.

What to do: you should be at rest and use a knee brace, apply ice packs for 15 minutes, 2 to 3 times a day, this can help relieve pain and combat inflammation. It is important to consult an orthopedist for a better evaluation and treatment with anti-inflammatory drugs, such as Ibuprofen or Naproxen, for example. In addition, physical therapy can be performed to strengthen the knee muscles and prevent tendonitis from developing again. Learn about other ways to treat patellar tendonitis.

4. Bursitis

Bursitis is the inflammation of the bursa, which is a small bag that contains fluid and functions as a shock absorber, as well as reducing friction between the bones, tendons and muscles of the joints. 

The knee has 11 bursae and generally, activities such as repeated knee bending or kneeling, playing sports such as jiu-jitsu, soccer, and volleyball, falls or blows can cause irritation and inflammation of the bursa, leading to pre- patellar bursitis, which causes pain in the upper part of the knee and inflammation.

What to do: You should rest and apply an ice pack for 15 minutes, 2 to 3 times a day. In addition, being an inflammation, bursitis should be treated with oral anti-inflammatory drugs, such as Ibuprofen or Diclofenac, for example, or by applying a corticosteroid injection right into the bursa. Other treatments include physiotherapy and surgery. 

5. Osteoarthrosis

Osteoarthrosis or osteoarthrosis of the knee is a rheumatic disease that causes degeneration of the cartilage of this joint, decreasing the quality, quantity and thickness of the cartilage, causing chronic pain. 

What to do: it is important to consult an orthopedist, since the treatment should be carried out with analgesics such as paracetamol or anti-inflammatory drugs such as Ibuprofen or Diclofenac. In addition, physiotherapy sessions are also recommended and, in some cases, the doctor may apply injections of corticoids or hyaluronic acid in the affected knee. 

6. Rheumatoid arthritis

Rheumatoid arthritis is a chronic, inflammatory, autoimmune disease that causes joint stiffness, pain, and swelling. Knee pain upon awakening may be caused by this disease, being that it is more intense during the first minutes of the morning and improves with movement.

What to do: analgesics and anti-inflammatory drugs can be used for pain relief but treatment should always be accompanied by a rheumatologist to evaluate the evolution of the disease, as well as a physiotherapist to improve the movement of the knee. Learn more about the treatment of rheumatoid arthritis.

7. Iliotibial band syndrome.

Iliotibial band syndrome causes pain in the lateral part of the knee and is very common in those who practice running, cycling or other sports that require repeated bending of the knee. Generally, this syndrome is related to weakness and poor muscle flexibility or errors in training with inadequate intensities and weights. In addition to the conditions in which the sport is practiced, such as the type of terrain, tennis or inadequate posture, for example. This type of pain should not be ignored, as it can worsen over time.

What to do: you can use an anti-inflammatory ointment 2 to 3 times a day or apply a frozen compress for 15 minutes. It is important, before practicing any physical activity, to perform muscle-strengthening activities, such as weight training or stretching, always under the guidance of a physical trainer. 

However, in case the pain in the lateral part of the knee occurs when practicing physical activity, the ideal is to consult an orthopedist for the correct diagnosis and treatment with anti-inflammatory drugs such as Diclofenac or Ibuprofen, for example, in addition to physical therapy to strengthen the muscles. Learn how iliotibial band syndrome is treated.

8. Meniscus injury

Pain in the knee when bending the leg, on the inside of the knee, climbing stairs, bending or inside the knee, for example, may indicate injury to the meniscus, which is a disc that functions as a cushion or shock absorber inside the knee. Generally, meniscus injuries are caused by physical activities such as judo, jiu-jitsu or by natural degeneration, which is the aging of the meniscus and can begin around 40 years of age. 

What to do: you should rest and avoid activities that move the knee a lot, in addition to physical therapy to strengthen the muscles of the knee. In some cases, the doctor can also apply injections of corticoids or hyaluronic acid in the knee. In the most severe cases, surgery may be indicated.

9. Patella (kneecap) problems

Other common causes of knee pain are problems in the patella, also called kneecap, such as patellar chondropathy, which is the wearing away of the joint around the patella, or chondromalacia patella, which is the softening of the cartilage in the patella. Generally, the causes of problems in the patella are aging, obesity, flat feet or the practice of sports such as running, for example. 

What to do: For runners, it is advisable to temporarily change sports to swimming or water aerobics until the knee musculature is strengthened. Physical therapy can help strengthen the knee, and after pain relief, weight training or weight-bearing exercises can be performed under the guidance of a physical trainer. In addition, the doctor may give injections of hyaluronic acid into the knee and, in severe cases, surgery may be recommended.

10. Baker’s cyst

Baker’s cyst, also known as a popliteal cyst, is a lump that forms behind the knee, in the joint, due to fluid accumulation. It causes pain in the back of the knee, swelling, stiffness and pain when bending the knee, which worsens with physical activity. The causes of Baker’s cyst are osteoarthritis of rheumatoid arthritis, for example. 

What to do: rest and consult an orthopedist to aspirate the cyst fluid or apply corticosteroid injections directly into the cyst. In case of the cyst ruptures, the treatment is surgical.