Types of knee injuries
There are four major ligaments in the knee. Ligaments are elastic bands of tissue that connect bones to each other and provide stability and strength to the joint. The four main ligaments in the knee connect the thighbone to the shin bone, and include:
- Anterior cruciate ligament (ACL)
- Posterior cruciate ligament (PCL)
- Medial collateral ligament (MCL)
- Lateral collateral ligament (LCL)
Cruciate knee ligaments
The anterior cruciate ligament (ACL) is one of the most common ligaments to be injured. An ACL injury happens when the ligament is stretched and torn during a sudden twisting motion when the feet stay planted one way, but the knees turn a different direction such as when skiing or playing basketball or football.
The posterior cruciate ligament (PCL) is also a commonly injured knee ligament when it sustains sudden, direct impact, such as from a sports tackle.
Collateral knee ligaments
The medial collateral ligament (MCL) is injured more often than the lateral collateral ligament, but both stretch and tear injuries to these ligaments commonly come from a direct blow to the outer side of the knee.
Injury to any of these four types of knee ligaments is marked by a popping sensation, knee or leg buckling and knee swelling.