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Anterior cruciate ligament

Anterior cruciate ligament (ACL) injuries account for more than 50% of knee injuries in the UK, affecting tens of thousands of people each year. If you’re one of them, ultrasound could help you to get back on your feet sooner.

What is your anterior cruciate ligament (ACL)?

The anterior cruciate ligament (ACL) is one of the major ligaments that holds your knee joint together. It connects the thigh bone to the shin bone, running diagonally through the knee joint and helps give the knee stability as well as controlling the forward and backward movement of the lower leg.

Why does an ACL tear occur?

Your anterior cruciate ligament can be torn as a result of a twisting injury, or if it has been over stretched. it can make it difficult to put weight on that leg and there may be swelling. Common in any sports that require lots of turning, and stopping and starting, like squash, football, tennis and skiing, it accounts for around 40% of sports injuries. You may experience a small or medium tear or there may be a complete tear (rupture).

Physiotherapy for an ACL injury

In minor cases of ACL injury, physiotherapy can restore enough strength and movement for you to return to your normal activities, although it’s often not enough to enable you to continue with some sports. Physiotherapy will also help strengthen your hamstrings and quadriceps, essential for helping to prevent future re-injury.

ACL surgery

If your knee continues to give way after an ACL tear or you have sustained more major damage, surgery could be required. It should restore movement and put an end to your knee giving way, although it is unlikely to be exactly as it was before your injury.

How can ultrasound therapy help treat an ACL tear?

Ultrasound can be used as part of your physiotherapy programme of rehabilitation after minor injury or following ACL surgery. Its beneficial effects are not fully understood, but it was first indicated as playing a role in aiding recovery of soft tissue injuries, such as ACL injury, in the first half of the twentieth century , and has been used in clinical practice since the 1950’s. A study on the effect of ultrasound following partial rupture of the Achilles tendon supports the belief.

Ultrasound is a very high frequency sound that cannot be heard by the human ear, but can be identified using a machine called an ultrasound scanner. It is thought to help reduce the healing time by attracting mast cells (cells that are part of your immune system and involved in healing) to the site of the injury. This helps to reduce inflammation more quickly and increase blood flow to further speed natural recovery.

Using ultrasound is also thought to increase the production of collagen. Ligaments and tendons are mainly made up of collagen, so by speeding up production of this protein, ultrasound is thought to help to aid faster recovery. After ACL surgery, scar tissue can build up on the ligament, restricting flexibility but ultrasound therapy is also thought to help limit this formation of scar tissue.

What happens during ultrasound therapy for an ACL injury?

During your session, your physiotherapist will pass an ultrasound beam directly over the site of the injury. The intensity and frequency of the beam can be varied, according to your individual needs: lower frequency application penetrates deeper into the body so is used when the injury is deep, and for injury closer to the skin surface a higher frequency can be selected.

If you’re serious about sport, or just don’t want to give up a loved hobby following a ruptured anterior cruciate ligament, adding ultrasound therapy to your rehabilitation programme could help you get back on your feet sooner. Find out more about the role of ultrasound in rehabilitation from injury or surgery and how Circle Health Group’s specialist Sports Injury Clinics can help you to get back to optimum fitness.