With instability of the knee, the person feels that they cannot trust the joint, which may give way and not allow confident movement.
Causes of general knee instability
A number of conditions may cause the knee to feel unstable, including -
- torn or avulsed cruciate ligament
- torn anterolateral ligament
- torn collateral ligament
- torn or avulsed meniscus or meniscus root
- avulsed meniscotibial or meniscofemoral ligament
- popliteus tendon tear
Causes of patellar instability
A number of conditions may cause just the patella to feel unstable, including -
Altered Tibiofemoral Joint Contact Mechanics and Kinematics in Patients with Knee Osteoarthritis and Episodic Complaints of Joint Instability. Farrokhi S, Voycheck CA, Klatt BA, Gustafson JA, Tashman S and Fitzgerald GK. Clin Biomech (Bristol, Avon). 2014 Jun; 29(6): 629–635.