Knee Sprain
Anterior Cruciate Ligament (ACL) Injury
Ligaments are short bands of tough fibrous tissue (soft tissue) that connects bones to other bones in and/or around joints. They limit the amount of mobility of a joint, to prevent certain movements that may damage a joint.
The anterior cruciate ligament (ACL) is one of four ligaments found in the knee that are critical to the stability of the knee joint. Its function is to control excessive knee motion by limiting the joint’s mobility. An ACL injury is often referred to as a sprain. A sprain occurs when threads/fibres in the ligament are stretched or torn. ACL injuries occur when bones in the leg suddenly twist in opposite directions under full body weight while the feet remain planted. There is a low chance of an ACL tear to be caused by contact with another player, such as a football tackle. A tear often occurs when pivoting or landing from a jump where it causes the ACL to stretch until the point of tearing. Soccer has a high incidence of ACL injuries as it involves many manoeuvers such as pivoting, sudden turns/change in directions, sudden stopping/starting, jumping and cutting. |
Classification:
An ACL injury can be classified as either an indirect or direct soft tissue injury, depending on how it was caused. For example, it would be classified as direct injury if the tear was caused by a tackle with another player. On the other hand, it would be classified as an indirect injury if the tear was caused by pivoting, sudden stopping/change in direction or jumping. This injury is not caused by overuse, its more of a traumatic (acute) injury.
An ACL injury is either classified as a grade I, II, or III soft tissue sprain.
Grade I Sprain
- A mild injury where the fibres of the ligament are stretch, but there is no tear
- There is little swelling and tenderness
- The knee joint doesn’t feel unstable or gives way during activity
Grade II
- A moderate injury where the fibres of the ligament are partially torn
- There is moderate swelling and little tenderness
- The knee joint may feel unstable or gives way during activity
Grade III
- A severe injury where the fibres of the ligament are completely torn (a.k.a ruptured); the ACL has torn completely into two parts
- There is tenderness – not a lot of pain when comparing to severity of injury
- There may be a lot or little of swelling
- The ligament can no longer control knee movements. The knee feels completely unstable or gives way at certain times
An ACL injury can be classified as either an indirect or direct soft tissue injury, depending on how it was caused. For example, it would be classified as direct injury if the tear was caused by a tackle with another player. On the other hand, it would be classified as an indirect injury if the tear was caused by pivoting, sudden stopping/change in direction or jumping. This injury is not caused by overuse, its more of a traumatic (acute) injury.
An ACL injury is either classified as a grade I, II, or III soft tissue sprain.
Grade I Sprain
- A mild injury where the fibres of the ligament are stretch, but there is no tear
- There is little swelling and tenderness
- The knee joint doesn’t feel unstable or gives way during activity
Grade II
- A moderate injury where the fibres of the ligament are partially torn
- There is moderate swelling and little tenderness
- The knee joint may feel unstable or gives way during activity
Grade III
- A severe injury where the fibres of the ligament are completely torn (a.k.a ruptured); the ACL has torn completely into two parts
- There is tenderness – not a lot of pain when comparing to severity of injury
- There may be a lot or little of swelling
- The ligament can no longer control knee movements. The knee feels completely unstable or gives way at certain times
Symptoms:
- Knee gives-way from under them - Sudden fall to the ground - Felt or heard a “pop” sound - Pain in the knee - Immediate onset of swelling in the knee - Instability of the knee – feeling a sense of looseness within it or that it can’t be trusted |
Management |