An ACL (anterior cruciate ligament) tear is an injury to one of the most important tendons in the knee. The ACL functions to stabilize the knee. Untreated ACL tears may seriously impact an individuals’ quality of life by restricting his/her mobility.
WHAT IS an ACL TEAR?
The ACL functions to keep the knee stable during physical activity. Injury occurs when this important ligament becomes over-stretched, and literally splits or rips. In a sense, the ACL is like a rope that is stretched until it breaks. An ACL tear may be a partial or complete tear of the ligament itself. In extreme cases, the ACL detaches from the bones in the knee entirely (avulsion).
ACL injuries are most common in athletes, particularly those engaging in high impact sports. Interestingly, 80% of ACL tears are non contact. That is, the injury occurs as the result of a bad landing after a jump, a sudden change in direction.. ACL injuries may also result from work place accidents, traffic accidents and falls. Some medical practitioners refer to ACL tears as sprains.
HOW ARE ACL TEARS OR SPRAINS CLASSIFIED?
- Grade One – a partial tear or sprain of the ligament. Happens rarely.
- Grade Two – a complete tear of sprain. More common
- Grade Three – the ligament has split or torn in two places.
- Most ACL injuries fall into the Grade Two and Grade Three Categories.
WHO IS MOST AT RISK?
- Athletes who play high impact sports such as football, hockey, soccer, basketball, skiing, cheerleading are prone to ACL tears, although not necessarily from a collision contact with another player.
- For reasons as yet unclear, female athletes are 6 to 10 times more likely to injure the ACL. Female skiers are particularly prone to ACL tears. Experts speculate that anatomical differences, together with different estrogen levels, between men and women may explain this phenomenon.
- Very young girls (15 and under) are especially prone to ACL injury.
- Older adults (40+) through the degenerative effects of ageing, or through awkward slips and falls, are also at risk.
HOW IS AN ACL TEAR OR SPRAIN DIAGNOSED?
- A doctor will compare the injured knee to the healthy knee to determine the extent of damage.
- Imaging Tests – X-rays or an MRI. An X-ray will not show damaged tissue but may rule out broken bones.
- Lachlan Test and Pivot Shift Test–orthopaedic tests that explore any abnormal amount of forward motion in the shin (tibia) in relation to the thigh bone (femur).
HOW ARE ACL TEARS TREATED?
Treatment varies with the severity of the tear and the patients’ normal activity level. ACL reconstruction surgery is generally contraindicated for the very young and the elderly. On the other hand, professional and dedicated amateur athletes may opt for surgery in order to return to competitive sports. Treatments may include: