What is the Anterior Cruciate Ligament?
What is the Anterior Cruciate Ligament?The Anterior Cruciate Ligament (ACL) is a rope-like structure that connects the femur (thigh bone) to the tibia (shin bone). It is an important stabilizer of the knee and when it is injured patients can experience knee instability or giving way.
Who is at risk for ACL injury?
ACL tears are a common injury among individuals in their teens or early adulthood. They most often occur as a result of a non-contact pivoting or twisting injury. When the injury happens it is usually very apparent. Patients will feel or hear a ‘pop’ inside their knee and this will be accompanied by a rapid onset of swelling or fluid buildup. In fact, the number one cause of knee swelling (i.e. hematoma) after a sports injury is an ACL tear. After the initial injury, most patients will have an encounter with the healthcare system where individuals are told to start some physiotherapy and see a surgeon for a consultation.
When does an ACL tear need physiotherapy vs surgery?
Initially, all patients with an ACL tear need physiotherapy. Even if surgery is a possible downstream scenario, patients will only be considered eligible for surgery once the swelling in the knee has been minimized, the muscles around the knee (i.e. the quadriceps) have been strengthened and/or re-activited, and there is full range of motion. In the absence of more complex injuries (like displaced meniscus tears or other associated ligamentous injuries), this can take anywhere from 3-6 weeks.
After this initial period of recovery and rehabilitation following ACL injury, the decision making process of whether or not surgery is needed comes into play. If patients can modify their activities and rehabilitate to an extent (usually after 3-6 months) where their knee does not give way, then ongoing nonoperative care is suitable. This may involve the use of a custom ACL brace for pivoting and twisting activities. When patients have persistent knee instability despite appropriate neuromuscular rehabilitation or if their work/sports/recreational activities necessitate pivoting, twisting, acceleration and deceleration movement patterns, then surgery can be considered.
Based on the above, it is clear that surgery is required for patients who are symptomatic (with instability) despite an initial period of rehab. For patients who are competitive athletes, early surgical management is often suggested to obviate the risk of knee instability and secondary damage to other structures in the knee.
What are the long term consequences of an ACL tear?
It is well known that a proportion patients with ACL tears develop osteoarthritis. Some estimates say upto 50% of people can develop xray signs of arthritis within 10 years. Surgery does not in and of itself change this risk. The key element is that ongoing knee instability that can cause secondary damage to meniscus and cartilage. Reinjury becomes the main culprit and the risk of this needs to be minimized. So whether physiotherapy alone can prevent this or surgery is required, the important part is that patients should be able to pursue a life of activity and meaningful endeavours without symptoms.
How is ACL reconstruction surgery performed?
ACL reconstruction is one of the most common surgeries performed by orthopaedic surgeons. Please watch the video here, for a technical overview of how ACL surgery is performed.
Overall, there is general agreement among surgeons that an ‘anatomic reconstruction’ with accurate placement of femoral and tibial sockets is the most important technique related factor to ensure success. The technique to accomplish an anatomic reconstruction has evolved over time and the specific details of how this is achieved may vary across different surgeons.