What is an ACL Injury and how are they treated?
Figure 1: Knee Pain - ACL Injuries - Physio Frenchs Forest, Physio Macquarie Park
Anatomy of the ACL:
Injuries to the ligaments of the knee are commonly seen in both sporting environments and during everyday life. Arguably the most important and well-known ligament found in the knee is the anterior cruciate ligament, which is a thick band of connective tissue that attaches the femur (thigh bone) to the tibia (shin bone). The anterior cruciate ligament acts with other ligaments, muscles and cartilage to ensure the stability of the knee joint.
The ACL stops excess forward and rotational movement between these two bones during activities such as running, jumping and changing direction. For this reason, injuries to the ACL are commonly see in sports that involve pivoting, acceleration and change of direction, such as football, netball and basketball.
Figure 2: Knee Pain - ACL Injuries - Physio Frenchs Forest, Physio Macquarie Park
How do ACL injuries occur?
Only 30% of all anterior cruciate ligament injuries are considered “contact injuries”, being sustained through contact or a collision with another person. The vast majority of ACL injuries (the other 70%) are classified as “non-contact” injuries, and usually occur as an athlete jumps, lands or changes direction. The most common mechanism of injury seen with ACL injuries involves a pivoting motion, while the knee is slightly flexed, and the foot is planted firmly on the ground. In some circumstances, the anterior cruciate ligament is the only structure injured within the knee joint, but due to the forces required to injure such a thick band of connective tissue, it is common to see other ligaments, or the meniscus of the knee damaged simultaneously.
What are the signs and symptoms of an ACL Injury?
The signs and symptoms of anterior cruciate ligament injuries will depend on the grade of damage to the ligament. Grade I injuries involve a stretching of the ligament, while grade II injuries involve a partial tear of the ligamentous fibres. The most serious type of ACL injury is a grade 3 injury, or a complete rupture of the ACL.
Pain & swelling (regular, but dependant on the level of injury, as stated above)
Tenderness around the knee joint
Loss of function or movement at the knee joint
Instability of the knee joint (the feeling of the knee giving way underneath your body weight)
How are ACL injuries diagnosed?
A consultation with a physiotherapist or medical professional is the best way to diagnose the cause of your knee pain. Your physiotherapist will likely suspect an ACL injury depending on the characteristics of your pain, and the initial mechanism of injury to your knee.
There are a number of physical tests that your physiotherapist or health professional will perform to confirm the diagnosis of an ACL injury. They will also order an MRI, which is the gold standard of imaging used to assess soft tissue injuries of the knee. Your physiotherapist will use both the results of the MRI, and the physical tests, to correctly and accurately diagnose the cause of your knee pain.
Figure 3: Knee Pain - ACL Injuries - Physio Frenchs Forest, Physio Macquarie Park
How are ACL injuries treated?
Once a diagnosis of an ACL injury has been confirmed, the first step is to consult a medical professional, to discuss the management of your injury and to formulate a treatment plan. Depending on the severity of the injury, and the level of activity that you wish to return to, your health professional (physiotherapist, orthopaedic surgeon or sports doctor) will suggest either undergoing surgery to repair your ACL, or non-surgical management of your knee.
Both treatment options have certain pros and cons, which should be discussed with your team of health professionals to decide which option suits you the most. A surgical approach is historically considered important if you wish to return to playing sports that involve jumping and changing direction at speed, but involves a 9-12 month period of intensive rehabilitation, and a period of hospitalisation after surgery. A piece of hamstring or patella tendon is used to replace the ACL within your injured knee, and must be allowed to heal sufficiently throughout the rehabilitation process.
Conservative, or non-surgical rehabilitation is a treatment pathway that has gained more support in recent years, and has good supporting evidence in a large number of cases. The time taken to rehabilitate such an injury is slightly shorter in comparison to surgery, as there is no hamstring or patella graft to protect, but potential reoccurrences of knee instability mean that this approach will not be the answer to everybody’s problems.
As discussed throughout this post, an injury or rupture of your anterior cruciate ligament is a serious condition, and requires the input of a qualified health professional to discuss the specifics of your injury, as well as your rehabilitation requirements.
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