Also Known As: Knee ligament tear, knee ligament injury

A sprain is overstretching one or more ligaments through twisting or wrenching. If you get pain, swelling or instability after an injury, you may have injured one of the ligaments around the knee joint and it is recommended to be evaluated by your doctor before going back to sport +++. Your physician may refer you to an orthopaedic surgeon for a thorough evaluation.The word "sprain" does not tell you which ligament is injured neither how bad it is injured.

A complete examination of the knee is necessary to determine the lesions.
X-rays will rule out a bone fracture and MRI may be ordered to evaluate for ligament or cartilage damage.

There are four knee ligaments.

o ACL (anterior cruciate ligament)
o PCL (posterior cruciate ligament)
o MCL and LCL (medial and lateral collateral ligament)

Anterior cruciate ligament (MORE about it)

• The anterior cruciate ligament (ACL) runs from the outside of the back of your thigh bone to the inside of the front (anterior) of your shin bone.
• Cruciate means in the form of a cross.
• The two cruciate ligaments cross over each other - the ACL crosses in front of the posterior cruciate ligament.
• Together they help to stabilise front to back movements of the knee.
• Your ACL is about half the strength of your medial collateral ligament (MCL). It's the most commonly injured knee ligament in sport.

Lateral collateral ligament (MORE about it)
The lateral collateral ligament (LCL) is like a thin cord that runs from the bottom of your thigh bone to the top of your shin bone on the outside of your knee. It's not usually damaged on its own but you will need to have it repaired quickly.

Medial collateral ligament (MORE about it)
This is on the inside of your knee and is taut when your leg is straight. It's a strong ligament but can be sprained or completely ruptured (torn) if you twist your straightened leg at the same time as being knocked sideways.

Posterior cruciate ligament (MORE about it)
The posterior cruciate ligament (PCL) runs from the inside edge of your thigh bone to the back (posterior) of your shin bone.

Docteur Jean Etienne Perraudin, last updated 1 Sept 2012