Why is my knee giving way?

Why is my knee giving way

The knee can give way for a number of reasons and can be a sign of injury or damage to the knee. This sensation of instability or ‘weak’ knees can increase your risk of falling and may occur suddenly or gradually increase over time. 

Signs and Symptoms 

Giving way of the knee can often be (but not always) associated with: 

  • Swelling 

  • Pain 

  • Locking, clicking, catching

  • Stiffness

  • Reduced range of motion

What is the cause?

Because the knee is a complex joint there can be multiple causes of giving way:

Ligament injury 

  • ACL

  • PCL

  • MCL

  • LCL

The main 4 ligaments of the knee provide huge amounts of stability to the knee. Damage to one or more of these ligaments will impact on the stability of the knee 


Meniscus tears (cartilage between the knee joints) can occur during twisting/pivoting/turning activities. Meniscus tears can often be associated with knee ligament injuries in younger athletes. 

Degenerative meniscus tears can also occur and are more common in people over the age of 40.

Meniscus tears can cause the knee to give way due to pain and depending on the size and type of the tear can also be due to instability.Seaforth Physiotherapy

Patella instability 

The patella (knee cap) normally glides through a groove at the front of the knee. A direct blow or twisting injury can displace the knee cap from the groove causing instability. If the knee cap no longer tracks in this groove then it can lead to giving way.


Thinning of the cartilage can lead to pain and instability in the knee. Arthritis can also cause joint stiffness, grinding and reduced range of motion leading to reduced physical activity. Exercise is vital to maintain muscle strength around the knee to prevent further instability and pain.

Nerve damage 

The femoral nerve controls the muscles that straighten the leg. Damage or irritation to these nerves can cause weakness and lead to a sensation of giving way.


Weakness to the muscles that control the knee can cause giving way when doing demanding tasks to the knee. Tasks such as walking up stairs, getting up from the floor or low chair.

Contact Us at Active Answers Physio in Seaforth if you have any questions. One of the team would love to help. 

Previously Known as Appleby Physiotherapy 



6/38 Kirkwood Street
NSW 2092
(02) 9907 9667

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