When one talks of the knee 'giving way' it means that the knee suddenly and unexpectedly is unable to support the person, and the leg just buckles, leading to stumbling or falling.
The mechanical trigger causes a sudden inhibition of the quads muscle, and the person cannot take weight on that side.
Causes of giving way, giving out or buckling of the knee
There may be a number of reasons for the knee suddenly giving out:
- a loose body in the joint
- a piece of torn meniscus catching in the joint
- a piece of loose joint cartilage catching in the joint