Locking when knee is bent a lot then popping on active extension
Fluid build up inside the joint
Loss of confidence in the knee for giving way easily on walking or weight bearing
Sports trauma: knee in flexion adduction internal rotation such as while playing soccer or martial arts.
A lot of high knee bending associated with social practices (floor tilers, gardening, lunch or dinner for Asians…)
Anterior Cruciate Ligament complete tear which is one of the main stabilizers of the knee from anterior dislocation
Meniscal tears: meniscus is a triangular structure on cross-sectional cuts responsible of anterior or posterior stability of the knee. When torn the fragment gets jammed between the femur and tibia and could cause blockage of movement.
Contact your doctor as soon as possible to avoid any cartilage loss by meniscal material scraping it off or any further meniscal damage following loss of ACL.
MRI is usually needed to determine the injuries.
Treatment of stable meniscal injuries or ACL tear would begin with oral medication and physiotherapy rehabilitation.
Unstable meniscal tears such as “bucket handle” or radial tears would need arthroscopic repair or removal of the damaged pieces to free the joint from blocking events: Keyhole procedure with two very small incision, one to introduce a small camera similar to the one in the cell phone and another to introduce the suturing device or very small grasper to remove the damaged pieces.
ACL tears for active young adults: ligament repair did not yield good results; a reconstruction is recommended. It consists of harvesting a ligament from around the knee (that would not affect knee function in the future) which will be introduced using very small holes in the joint then fixed to bone.