An anterior cruciate ligament (ACL) injury is commonly called an ACL tear.
The ACL is one of the main stabilising ligaments in the knee, connecting the thighbone (femur) to the shinbone (tibia).
What are the symptoms of an ACL tear?
Typical symptoms include:
A popping sound when the knee ligament ruptures
Pain immediately after an injury
Pain when standing or placing pressure on the injured leg
Difficulty with knee movements or reduced range of knee motion
Feeling of instability, or loose knee joint, with the knee 'giving way' during daily activities
Swelling of the affected knee within 24 hours
Difficulty walking or limping while walking
What causes an ACL tear?
ACL tears commonly occur during sports and fitness activities that involve:
Sudden slowing down
Sudden change of direction
Pivots with the foot firmly planted
Awkward landings from a jump
Overextension of the knee joint
Direct blows to the knee or collisions
What are the risk factors for an ACL tear?
Your risk of getting an ACL tear is higher if you:
Are a woman.
Have poor physical conditioning.
Play sports that involve start-stop movements, pivoting or sudden changes in direction, as these movements cause the knee to twist or turn. Examples of these sports include soccer, basketball, netball, tennis, and gymnastics.
Use poorly maintained or ill-fitting sports equipment.
Wear ill-fitting shoes.
What are the complications and related diseases of an ACL tear?
If you have an ACL tear, you have a significantly higher risk of developing knee arthritis.
This increased risk remains regardless of whether the tear was surgically repaired. Experts believe that the inflammatory response of the knee to the injury itself contributes to arthritis.
About 1 in 2 people who experience a torn ACL will experience the onset of arthritis within 10 – 15 years. As ACL injuries are common among younger people and athletes, this could mean that the onset of arthritis can occur in the prime of their lives.
How do you prevent an ACL tear?
You can reduce your risk of an ACL tear by strengthening your leg muscles and practising good form.
Strengthening your leg muscles will help protect your knees. Exercises such as squats and lunges help with overall strengthening, and exercises that target the hamstrings may be especially helpful.
When you practise good form, your improved core strength and balance make you more stable and less likely to injure your knees. Practising good form means:
Landing evenly on both feet
Bending your knees when landing
Aligning your body and feet while landing
Keeping the knees shoulder width apart while landing