The anterior cruciate ligament (ACL) is one of the most commonly injured ligaments of the knee. It occurs in all different sports, and in all different ways. In general, the incidence of ACL injury is higher in people who participate in high-risk sports, such as basketball, football, skiing, and soccer.
Over 50 percent of ACL injuries occur in combination with damage to other structures of the knee, namely the meniscus, articular cartilage, or other ligaments. It is common for bone bruising around the attachment of the ACL when damaged.
The cause of ACL injuries is estimated to be more common through non-contact mechanisms while it is less commonly resulted from direct contact with another player or object.
The mechanism of injury is most commonly associated with deceleration and pivoting or sidestepping maneuvers, and awkward or heavy landing.
The results of several studies have shown that female athletes have a higher rate of ACL injury than male athletes in most sports. Several factors can explain this: differences in physical conditioning, muscular strength, and neuromuscular control. Other factors that may explain their higher ACL injury rates include pelvis and lower extremity (leg) alignment, and increased laxity of the ligaments.
Common symptoms of ACL injury includeimmediate pain and swelling, and a general feeling of knee instability. Within a few hours of a new ACL injury, people often have a large amount of knee swelling, a loss of full range of motion, pain or tenderness along the joint line and discomfort while walking.
To assess whether the ACL has been torn, special tests are performed to identify any laxity in the ACL ligament. If the ACL is torn, there is increased forward (upward or anterior) movement of the tibia in relation to the femur (especially when compared to the normal leg) and a soft, mushy endpoint (because the ACL is torn) when this movement ends.
The natural history of an ACL injury without surgical intervention varies from patient to patient and depends on
- the patient’s activity level,
- degree of injury and,
- instability symptoms.
If the ACL is only partially torn, the outcome is often good, with the recovery and rehabilitation period usually at least three months. However, some patients with partial ACL tears may still have symptoms of instability. A thorough physiotherapy assessment helps identify those patients with unstable knees due to partial ACL tears.
Complete ACL ruptures that do not undergo surgery have a much less favorable outcome. After a complete ACL tear, most people are unable to participate in pivoting-type sports, while others have instability during even normal activities, such as walking. Those complete ACL tears that have not had surgery, up to 90 percent of patients will have meniscus damage 10 or more years after the initial injury.
In nonsurgical treatment, progressive physiotherapy of a partially torn ACL ligament can restore the knee to a condition close to its pre-injury state. However, this relies on compliance of the person to do the exercises required of them. However, many people who choose not to have surgery may experience secondary injury to the knee due to repetitive instability episodes.
When there are other injuries in addition to the ACL injury, surgery is mjore commonly advised. However, deciding against surgery is reasonable for select patients. Nonsurgical management of ACL tears without any other injury can be successful in the following cirumstances:
- partial tears with no symptoms of instability
- complete tears with no symptoms of knee instability while doing low-demand sports (people must be willing togive up high-demand sports
- those who do light manual work or live sedentary lifestyles
- children that still have open growth plates.
ACL tears are usually repaired with a graft made of tendon. The grafts commonly used to replace the torn ACL include:
- Patellar tendon autograft (autograft comes from the patient)
- Hamstring tendon autograft
- Quadriceps tendon autograft
- Allograft (taken from a cadaver) patellar tendon, Achilles tendon,
The success rates of people treated with surgery of the ACL are between 82 – 95 percent.
Recurring instability and failure of the graft accounts for approximately 8 per cent of people.
The goal of surgery is to prevent further instability of the knee, and to allow people to return to their chosen sports, without the occurrence of further damage.
What to consider when deciding for or against ACL surgery
- People that participate in sports or jobs that involve pivoting, turning, or heavy manual work are encouraged to have surgery.Activity, not age, should determine if surgical intervention should be considered.
- In young children or adolescents with ACL tears, surgery poses a risk of growth plate injury, which can then lead to bone growth problems at a later age.
- Those who have a torn ACL and significant knee instability have a high risk of developing secondary knee damage, and should therefore consider ACL reconstruction.
- In cases of combined injuries (as mentioned above), surgical treatment may be warranted and generally produces better outcomes. As many as 50 percent of meniscus tears may be repairable and may heal better if the repair is done in combination with the ACL reconstruction.
It is always best to consult one of our physiotherapists at Active Physio Health if you are questioning whether to have surgery or not. This information is a general guide, but much more information can be obtained by the physiotherapist with a thorough assessment. If you would like to find out more on ACL injuries, please visit our website www.activephysiohealth.com.au , or call us on ph. 49725155 to book an appointment.