Ligaments are the structures that attach one bone to the other, kind of tie beams to bind wooden poles together.

Ligaments stabilise the joint by binding together the bones of the joints. Any injury to these ligaments render the joint unstable leading to slipping or dislocation of the joint in extreme conditions.

There are many ligaments in the knee joint, of Major concern are-
Between Femur and Tibia
Anterior Cruciate ligament(ACL)
Posterior cruciate ligament (PCL)
Medial coeteral ligament (MCL)
Lateral or Fibular collateral ligament (LCL)
Between Patella and Femur
Medial and lateral Patello femoral ligaments

Ligaments tear when the joint is subjected to forces over and beyond their strength to hold the bones together, commonly encountered in Sports track and field events, Road traffic accidnets.

There are two situations here
1. Acute onset like an injury during sports or fall from bike or slip on staircase, there is a sudden onset pain and swelling in the knee with difficulty in walking or putting the keg down
2. Another scenario is, patient might have had a remote history of injury, intially pain subsided and was fine for a period but slowly develops a feeling of Instability in the knee like slipping while walking or unable to jog run, difficulty while rising from chair or getting out of a car

First your Orthopedician will ask you about your complaints, examine the knee for any signs of ligament injury and then run some diagnostics to confirm the clinical findings.
MRI is the ideal diagnostic imaging for any ligament injury.
Not all patients who have a ligament injury need surgery.
On an average only 30% of patients who have ligament injury develop instability in the joint.
Of those 30% only 10% who fail a supervised Physiotherapy for rehabilitation will need surgery
So, the treatment options are
– NO instability on clinical examination- supervised or guided Physiotherapy
– Instability on clinical examination and MRI evidence of a complete tear- Surgery

This is best done with a one on one discussion with your Orthopedician to your treatment options, rehab time, toe for fit to resume work/driving.