Acl Tear

the ACL keeps the knee stable, controlling the back and forth motion of the knee. The ACL is the most commonly torn ligament within the knee.

What is an ACL tear?

The Anterior Cruciate Ligament is a ligament within the knee (connecting diagonally from the bottom of the femur to the top of the tibia). The function of the ACL is to keep the knee stable, more specifically controlling the back and forth motion of the knee. The ACL is the most commonly torn ligament within the knee. There are a variety of different types of tears. 

  • Grade 1 sprain – Minor damage to the ligament but the knee is still stable 
  • Grade 2 sprain – The ligament is overstretched causing a partial tear of the ligament therefore the knee might feel “loose” and unstable
  • Grade 3 sprain – This is when there is a complete tear/rupture of the ligament splitting the ligament into two and causing the knee joint to become unstable


The ACL can be torn in a variety of different ways; it can be from direct contact/trauma to the knee (least common), rapid change of direction, landing awkwardly, sudden change of pace (sudden stop whilst sprinting) and more can all cause the ACL to tear.  Essentially it is any sudden movement that causes the ACL to be put under too much stress that can cause the tear. 


It is quite common to hear a popping noise when you tear your ACL followed by the feeling of your knee giving way from underneath you. These are not the only signs of a torn ACL, others include; swelling of the knee within the first 24-48hours, locking sensation within the knee, pain whilst walking/load-bearing feeling like the knee will give again, loss of range of motion and more.

Options available

There are two main options available for ACL tears; surgical and non-surgical (conservative). A variety of different factors can go into how an individual approaches the ACL tear such as; the severity of the tear, past medical history, age, physical health, occupation physical activity demand and more.

Surgical approach

ACL reconstructive surgery is as said in the name essentially just a process to reconstruct the ligament. This is done using a new ACL graft. The old damaged ACL is removed and the new graft put in attached directly onto the bone. The type of ACL graft can also vary between:

  • Autograft – using a tendon from somewhere else within your body (e.g. hamstring/patellar)
  • Allograft – using a tendon from another person
  • Synthetic – using artificial materials

Following the surgery the individual will have to go through an extensive rehab program (normally between 6-10months varying on each individuals needs) focusing on regaining mobility, strength and full function. 

You will tend to find people with a full rupture, higher physical demand, athletes, further damage done to the surrounding structures too will tend to go for the surgical approach. 

Non-surgical (conservative) 

Taking this approach can also depend on a variety of different factors just like the surgical approach. After an initial rest and recovery period the conservative approach will consist of an extensive progressive rehab program to restore the knee to as close to its pre-injury state as possible by restoring range of motion, strength and function. The key to non-surgical treatment is ensure the knee feels stable and educating the individual on how to prevent knee instability as people who opt out of having surgery may experience secondary injury to the same knee due to the instability.