What is an ACL Tear?
The Anterior Cruciate Ligament (ACL) is one of four ligaments that connects the femur (thigh bone) and the tibia (shin bone) in the lower limb. Its role is to resist anterior translation (forward movement) of the tibia relative to the femur, and when a movement like this is extreme, it can result in a sprain or tear. The ACL can also tear with extreme rotational movements.
The degree of injury is classified by grades. A grade 1 injury involves microscopic tears which will not typically affect joint stability. A grade 2 injury is diagnosed when the ACL is partially torn, and the patient experiences an unstable knee when walking and standing. Finally, a grade 3 injury is quite severe as the ACL is completely torn and the patient will experience an extremely unstable knee.
How did I get an ACL Tear?
ACL tears can occur from either direct contact to the site (30% of injuries) or no contact at all (70% of injuries), with the main mechanism of injury being pivoting, decelerating, and jumping movements. The most common movement associated with ACL tears is a cut-and-plant movement.
Interestingly, women are three times more susceptible to ACL injuries than men. This is considered a risk factor for an ACL tear, along with environmental factors (high friction between shoes and playing surface) and pre-existing degeneration of the knee.
There are both internal and external risk factors. Internal risk factors involve the individual’s anatomy, hormone levels, and neuromuscular risk factors. External factors are typically related to the type of sport, the footwear, the foot-surface interface, and environmental conditions.
Symptoms of an ACL Tear
Symptoms of an ACL tear can include the following:
- loud “pop” noise at the time of injury/popping sensation in knee
- severe pain in knee
- severe, rapid swelling
- instability in the knee and/or “giving way” when weight bearing
- loss of range of motion (cannot fully extend the knee)
- tenderness across knee surface
How is an ACL Tear diagnosed?
Your physiotherapist will perform a physical assessment to diagnose your condition. A series of special tests will be done, such as the Lachman Test, Anterior Drawer Test, and Pivot Shift. Additional tests may be done, such as an X-ray, MRI, and/or Ultrasound to rule out any other injuries.
Treatment of an ACL Tear
The first treatment for an ACL tear follows the RICE protocol. Rest, Ice, Compression, and Elevation to reduce pain and swelling soon after the injury.
Surgery may be recommended or required as there is poor blood flow to this ligament; therefore, it can after poor healing potential. If you are an athlete looking to return to sport, ACL reconstructive surgery may be offered with extensive rehabilitation being required – both before and after your surgery.
If surgery is not required or recommended, Physiotherapy is a great option to strengthen the muscles surrounding the knee. This way, these muscles can compensate for the lack of the ACL and provide more stability to the knee.
Treatment is dependent on the grade of your injury. If you have a grade 1 or 2 injury, it is possible that surgery will not be required, and physiotherapy alone will be enough to treat your injury to the level required for your daily tasks.
As mentioned above, athletes will typically endure the surgery to be able to return to their full level of sport, while some non-athletes find that physiotherapy is sufficient to get back to their normal activity levels.