Back in Stock. Hurry, Get Yours!

Knee pain when bending. What's the cause?

Knee movement is crucial for performing daily activities such as climbing stairs and sitting in a chair. Even exercises like squats and lunges require bending of the knees. However, the knees bear a significant amount of pressure when they support the body's weight, and this pressure increases with each kilogram of body weight. As a result, it is not surprising that our knees endure a tremendous amount of stress on a daily basis, which can lead to discomfort and pain. The pain associated with knee movement can be extremely bothersome because our knees are in motion multiple times throughout the day and play an essential role in our daily activities.

Many individuals experience this type of pain, which can vary in intensity and location. There are numerous potential causes of knee pain when bending, including damage to the bones, ligaments, muscles, and tendons in and around the knee joint. Therefore, it is crucial to consult a doctor to obtain an accurate diagnosis. Once the cause of the pain is determined, treatment options can be explored and discussed.

Athletes and individuals who engage in physically demanding activities are more likely to experience knee pain due to the overuse of their joints. However, whether the knee pain is caused by ageing or injury, it can be a nuisance and, in some cases, even debilitating.

Associated Symptoms

Knee pain when bending can and is commonly accompanied with:

  • Weakness or instability
  • Popping or crunching noises
  • Inability to fully straighten the knee
  • Swelling and stiffness
  • Redness and warmth to the touch
  • Visible deformity in your knees or legs

What Causes Knee Pain?

Knee pain when bending can have various causes, such as arthritis, overuse, or sports injuries. Some cases of knee discomfort have clear causes, while others, like arthritis or degenerative conditions, require professional evaluation and diagnosis.

Traumatic injuries are often the result of sports, falls, or accidents, typically involving impacts or twisting motions. These injuries are usually immediately noticeable or become apparent within a few hours, with worsening symptoms in the following days. Swelling and inflammation may also occur if the trauma exceeds the knee's structural tolerance, leading to breaks, ruptures, or tears.

The most commonly affected structures in the knee joint are the ligaments, bones, and menisci. Injuries to these areas can cause long-term pain and impair normal knee function for a significant period after the initial injury. Less severe traumatic injuries may result in painful bruises that heal relatively quickly. Untreated old knee injuries can also lead to chronic or intermittent knee pain. Here are a few examples of traumatic knee injuries:

  • Kneecap dislocation
  • Fractures of the kneecap or other bones
  • Torn or strained ligaments, such as the Anterior Cruciate Ligament (ACL) or Medial Collateral Ligament (MCL), commonly occurring during twisting or excessive strain.
  • Meniscus tear, often accompanied by pain on the inside or outside of the knee joint, often accompanied by a snapping or clicking sound during the injury.

Overuse injuries develop gradually over time as the knee is constantly subjected to excessive use and strain. This type of injury leads to intermittent pain with varying intensity. Typically, engaging in the activity that caused the overuse will trigger the pain again, particularly weight-bearing activities like bending. Here are some examples of overuse injuries:

  • Bursitis: Inflammation of the knee bursa, resulting in swelling, warmth, and pain either over or below the knee.
  • Iliotibial band syndrome: Injury to the thick band extending from the hips to the outside of the knee. People often experience a burning pain associated with repetitive downhill running.
  • Patellofemoral syndrome: Dull pain located at the front of the knee, around the kneecap. It occurs due to excessive pressure, tension, abnormal weight distribution, poor posture, misalignment, or muscle imbalance in the lower legs.
  • Patellar tendonitis: Causes burning pain in or around the base of the kneecap.

In addition to the previously mentioned causes, there are several other factors that can contribute to knee pain when bending:

  • Osteoarthritis: This condition leads to general knee pain, swelling, and stiffness, particularly in the morning.
  • Baker's cyst: This cyst can cause tightness and swelling behind the knee, resulting in pain, especially during bending.
  • Osgood-Schlatter disease: Common among adolescents experiencing growth spurts, this condition involves irritation and tenderness of the patellar tendon, just below the kneecap, often due to bony growth plates in the area.
  • Obesity or hip misalignment: Increased pressure and tension on the knees can occur due to obesity or misalignment of the hips, such as hip aberration, leading to pain when bending the knees.

Possible solutions to the issue

  • Exercise: Physical activity plays a vital role in improving knee mobility and promoting the health of soft tissues. Strengthening exercises that target the muscles supporting the knee, such as squats and lunges, can enhance stability, provide extra joint cushioning, and reduce the risk of injury. These exercises involve knee movement against resistance from weights or bodyweight, improving range of motion and muscle control.
  • Modify your activities: It is important to listen to your knees and adjust your activities accordingly. If certain activities cause knee pain, consider reducing the intensity, impact, or loading of those activities. Gradually progress and improve the difficulty as your knees tolerate.
  • Orthotics: Shoe inserts and insoles can help stabilize and align the ankle and foot, relieving knee pain by reducing pressure on the joint. Wearing proper footwear can also have a similar beneficial effect.
  • Medication: Your doctor may prescribe analgesics and anti-inflammatory medications to alleviate pain and reduce swelling.
  • Physical therapy: A physical therapist can provide manual therapy techniques to relieve pain and guide you through a customized exercise plan to reduce knee pain.
  • Surgery: In more severe cases, surgery may be considered as an option. Surgical interventions can involve repairing tendons, removing damaged parts of the meniscus, or even total knee replacement, depending on the specific condition and its severity.

When to see a doctor

Knee pain should be taken seriously as it can indicate various medical conditions. If your knee pain persists for more than a few days, even with home treatment, it is crucial to seek medical attention for an accurate diagnosis. Furthermore, if you notice any redness or swelling around your knee, it is important to make an appointment with your doctor promptly to assess the situation. Timely medical evaluation is essential to address the underlying cause of knee pain and prevent potential complications.


In conclusion, it is of utmost importance to have your knee evaluated by a healthcare professional, especially in the case of a traumatic knee injury. Seeking a definitive diagnosis not only provides peace of mind but also accelerates the healing process. By understanding the underlying cause of your knee pain, you can take appropriate steps towards effective treatment and recovery. Don't delay in getting the necessary assessment, as it can make a significant difference in your overall well-being and rehabilitation.


Author Bio

Ines Pinheiro

Inês Pinheiro

Certified Physiotherapist for Shoulder and Knee Injuries

Inês is a skilled physical therapist with a special interest and extensive experience in working with athletes, specifically football players and also neurologic patients.



  1. Knee Pain When Bending? Here’s What You Can Do About It (no date) Guthrie. Available at: 
  2. Knee Pain When Bending and Squatting (2023) Spring Loaded Technology. Available at:
  3. Knee Pain When Bending: Causes, Prevention, Treatment, and Best Exercises (no date) hingehealth. Available at:
  4. Why Do My Knees Hurt When Bending? (2022) The Orthopaedic Institute. Available at: 
  5. What Causes Knee Pain When You’re Bending It, and How’s It Treated? (no date) Healthline. Available at:

Leave a comment

Please note, comments must be approved before they are published