Knee Instability is the sensation of the joints within the knee moving excessively in any particular direction with activity, especially more dynamic or twisting types of movement. This will typically be accompanied by weakness and loss of power in the knee.

Instability can be caused by injury or structural damage to various structures within the knee. It can also be caused by just having poor muscle control and increased laxity (reduced tension or tightness) in the ligaments around the knee.

Another cause of knee instability may be due to the result of pain within the knee and its associated muscle inhibition (pain causing the muscles around the knee to not function effectively, causing feelings of instability), as is common with moderate to severe knee osteoarthritis.

A few of the main structures that could have been damaged from a previous or recent injury to the knee, that may have not been properly diagnosed or detected could have been:

• Meniscus tear – Fibro-cartilage buffer that absorbs shock between the Femur (thigh bone) and Tibia (Lower leg bone). There will usually be associated locking or catching in the knee with this.
• Ligament tear – there are various ligaments in the knee that attach between bones within the knee. Ligaments provide stability between the two bones it attaches to by restricting excessive movement in the plane in which that ligament runs. Ligaments can be torn or ruptured (completely torn right through)
• Patella Subluxation/Dislocation – this is when your kneecap either partially moves out of its groove within the knee (subluxation) and moves back in, or dislocates (dislocation), which is where it moves completely out of its groove and then back in.

Assessment:

Your physio will start their assessment by asking a series of questions in an attempt to narrow down what the likely cause of your knee instability may be. 

• What were you doing when you first experienced your knee instability?
• Have you had any previous injury to that knee? If so was there any significant swelling and associated pain?
• What is the most common activity that causes your knee instability now?
• Has your knee been treated or assessed by a physio before?

After your physio has finished asking the questions they will then assess your knee visually, and assess the movement and function of your knee. This will include asking you to perform certain movements and actions. They will look at swelling, muscle tone and note any asymmetry in the knee compared with the uninjured knee.

Your physio will also test the various ligaments and other structures within the knee to ascertain whether they may have been injured previously.

If your physio finds that there is no history or evidence of structural damage within the knee and that you may instead have poor muscle control and increased laxity in your knee ligaments, they will devise a treatment program that targets this as follows: (This program outlined is for a patient returning to sport. If you are getting instability with activities of daily living or work activities, but do not participate in sport then weeks 1-6 weeks should be sufficient)

Stage 1: 0-4 weeks – 2 sessions per week

Targeting – massage and release of tight structures, joint mobilisation if needed, strengthening program for the core, hip and knee – exercises in the sagittal plane. Knee taping or hinge brace may be used in this period dependant on patient presentation. Balance/stability exercises

Stage 2: 5-8 weeks – 2 sessions per week

Taping only – no use of hinge brace unless needed. Progressing load and exercises in frontal planes. 4-way hip and knee exercises can be introduced in this phase f the patient is progressing well. Increase proprioceptive stability/exercise. Sports-specific drills can be added from week 6 onwards.

Stage 3: 9-12 weeks – 1 session per week

Increase the intensity of sport-specific drills and plyometric activities. Return to sport cleared when the patient is able to partake in contact and non-contact sport-specific drills without symptoms, weakness, instability or pain for a given training period e.g. 45min, over a period of 1-2 weeks prior to re-commencement.

If you need help with pain or immobility to get you moving again, or need a tailored exercise program, book in for your treatment now with one of our exercise, physio, or pain specialists via 1300 012 273 or head to our website and book a session at your nearest clinic.