The knee is a complex structure consisting of many components. Its is prone to a wide range of disorders from congenital defects to trauma in sport to simply wearing out.



Ligament Injury

What are knee ligaments?

There are four major ligaments in the knee. Ligaments are strong bands of tissue that connect bones to each other and provide stability and strength to the joint. The four main ligaments in the knee connect the femur (thigh bone) to the tibia (shin bone), and include the following:

  • Anterior cruciate ligament (ACL) – the ligament, located in the center of the knee, that controls rotation and forward movement of the tibia (shin bone).
  • Posterior cruciate ligament (PCL) – the ligament, located in the center of the knee, that controls backward movement of the tibia (shin bone).
  • Medial collateral ligament (MCL) – the ligament that gives stability to the inner knee.
  • Lateral collateral ligament (LCL) – the ligament that gives stability to the outer knee.

How are cruciate ligaments injured?

The anterior cruciate ligament (ACL) is the most common ligament to be injured. The ACL is often stretched and/or torn during a sudden stepping motion on a planted foot , jumping up or landing or by direct trauma to the knee (a rugby tackle). Skiing, basketball, netball and all codes of football are sports that have a higher risk of ACL injuries.

The posterior cruciate ligament (PCL) is a less common ligament to become injured in the knee. However, the PCL injury usually occurs with sudden, direct impact, such as in a car accident or during a football tackle.

What are the symptoms of a cruciate ligament injury?

Most cruciate ligament injuries are a sudden event. There may be an audible snap or popping sound as the injury occurs, followed by the leg buckling when trying to stand on it. The player usually has to come off the field of play. The  injury is frequently followed by rapid swelling over the next 24 hours. These symptoms mean that you should get the knee seen and probably have an MRI.

The symptoms of a cruciate ligament injury may sometimes resemble other conditions or medical problems.

How are the collateral ligaments injured?

The medial collateral ligament is injured more often than the lateral collateral ligament. Stretch and tear injuries to the collateral ligaments are usually caused by a blow to the outer side of the knee such as a tackle or another player striking the knee from the outside. 

What are the symptoms of a collateral ligament injury?

Similar to cruciate ligament injuries, an injury to the collateral ligament causes the knee to pop and buckle, causing pain and swelling on the medial side of the knee. 

However, the symptoms of a collateral ligament injury may resemble other conditions or medical problems.

How is a knee ligament injury diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for a knee ligament injury may include the following:

  • X-ray – A diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
  • Magnetic resonance imaging (MRI) – A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body; can often determine damage or disease in a surrounding ligament or muscle. This is the most accurate way of radiologically assessing knee ligament injuries and will often be ordered by your referring doctor. 
  • Arthroscopy – A minimally-invasive diagnostic and treatment procedure used for conditions of a joint. This procedure uses a small, lighted, optic tube (arthroscope) which is inserted into the joint through a small incision in the joint. Images of the inside of the joint are projected onto a video screen  to help your surgeon evaluate knee disorders.

Treatment for knee ligament injuries

Specific treatment for a knee ligament injury will be determined by your doctor and may include:

  • Initial treatment consisting of Ice, compression and elevation which will usually  involve your physiotherapist.
  • Pain relief medication and or anti-inflammatory medications
  • Splints of braces to support or stabilise
  • Rehabilitation and strengthening in preparation for return to sport.
  • Surgical proceedures such as Arthroscopy and or repair / reconstruction

Meniscal Tears

The meniscus is a cartilaginous cushion in the knee which helps in shock absorbing, lubrication and stability. Whilst the ends of the thigh and shin bone have a cartilage coating the two menisci are more mobile and spread the load throughout the range of knee movement. The menisci can be torn during twisting injuries of the knee. In younger patients this is usually a result of a specific injury whilst after middle age the meniscus can tear with less obvious mechanisms and sometimes occurs spontaneously.

Once the meniscus is torn you may experience joint line pain, swelling or locking/clunking. MRI usually demonstrates the tear.

Meniscal tears in younger age groups should be seen by one of our team as they frequently require surgical intervention.

Meniscal tears over 50 years of age can often be managed conservatively at least initially. Your GP may suggest that you see a physiotherapist. Failure to improve or symptoms of locking/catching may mean that you could need surgical intervention.

Surgical procedures for meniscal tears have undergone a transformation over the last two decades. Techniques of meniscal repair rather than removal have greatly advanced. This has particularly affected the younger patients who will benefit from meniscus preserving surgery. In situations where the meniscus is lost completely, meniscal transplant can provide a solution.

Our surgeons actively keep up to date with advances and continue to perform research in the important field of meniscus restoration.



Anterior Cruciate Ligament (ACL) Reconstruction

The anterior cruciate ligament (ACL) is one of four stabilising ligaments of the knee. It prevents abnormal anterior displacement and rotation of the lower leg. The ACL may be injured with excessive pivoting or twisting of the knee as well as hyperextension, hyperflexion or lateral trauma to the knee. When the ACL is torn, the patient may hear or feel a “pop” in the knee, followed by swelling and difficulty continuing their activity. The patient may have a hard time walking and may also feel a sense of instability. An ACL tear is best diagnosed in a physical examination by an orthopaedic physician. An MRI (magnetic resonance image) may be obtained to confirm an ACL tear, as well as identify injury to other parts of the knee.

Cartilage Repair

For knee joints to function properly, the knee requires a smooth gliding articular cartilage surface on the ends of the bones. This surface is composed of a thin layer of slippery, tough tissue called hyaline cartilage. This cartilage acts to distribute force during repetitive pounding-like movements, such as jumping or running. A knee injury can cause cartilage lesions or locking, which can cause localized pain hindering movement and causing further deterioration of the joint surface.


Chondromalacia patellae is a painful disorder of the knee, most commonly affecting adolescents, in which the cartilage directly behind the kneecap is damaged. When it occurs in adults it is known as retropatellar arthritis. The cause is uncertain. Pain is felt when the knee is straightened and is particularly bad when running, jumping, climbing or descending stairs. Most orthopaedic surgeons agree that chondromalacia should first be treated conservatively.

Knee Arthroscopy

Arthroscopy is a surgical technique whereby a tube-like instrument is inserted into a joint to inspect, diagnose and repair tissues.

Please remember that medical information provided by Brisbane Orthopaedic and Sports Medicine Centre, in the absence of a visit with a physician, must be considered as an educational service only. The information contained in this website should not be relied upon as a medical consultation. This website is not designed to replace a physician’s independent judgement about the appropriateness or risks of a procedure for a given patient.