Injury Centre | Knee | ACL Strain

 

Anterior cruciate ligament strain

Anterior cruciate ligaments

The knee is stabilized by four main ligaments: 2 collateral ligaments and 2 cruciate ligaments both anterior and posterior. The cruciate ligaments attach to the femur (thigh bone) and travel within knee joint to the upper surface of the tibia (shin bone). The ligaments pass each other in the middle of the joint forming a cross shape, hence the name "cruciate".

The anterior cruciate ligament (ACL) prevents the tibia from shifting forwards below the femur. The posterior ligament prevents backwards displacement of the tibia. Both ligaments are vital for the stability of the knee particularly in sports that require a lot of twisting and changing of direction such football and rugby.

How is the ACL injured?

The ACL is injured either through twisting the knee or through an impact to the side of the knee - often the outside, such as a rugby tackle. Most ACL injuries come from twisting of the knee when the foot is firmly planted on the ground, deceleration or landing from a jump. If the ACL is injured through impact then it is very likely the medial ligaments and the menisci may also be injured - this known as "O'Donohue's triad".

Symptoms of an injured ACL?

• There may be an audible pop or crack at the time of injury.
• ACL injuries are extremely painful, in particular immediately after sustaining the injury.
• Swelling of the knee- this may occur quite rapidly.
• Decreased ability to straighten the knee.
• Positve signs in the anterior drawer test.
• Tenderness at the medial side of the joint- this may indicate meniscal damage.

What can the athlete do?

• Apply RICE (Rest, Ice, Compression, Elevation) immediately.
• Seek medical help immediately.

What can a professional and when is surgery recommended?

• A doctor or sports injury professional can assess the knee and confirm the diagnosis.
• Refer the athlete for surgery or advise on conservative non surgical rehabilitation. Surgery is generally suitable for a young, motivated sports person who is likely to stick to a challenging rehabilitation program. Surgery will involve reconstructing the ligament from a tendon elsewhere in the body, or simply repairing the damaged ligament.
• In older, less active people, surgery may not be advised, largely due to the demands they will place on the knee in the future and the likelyhood of being able to a adhere to a challenging rehabilitation programme.
• Advise on immediate rehabilitation which should begin shortly after the time of injury, not necessarily from the time of surgery. making sure the injured leg is in the best possible fitness prior to surgery will ensure more successful outcome after surgery.

What does surgery involve?

• Surgery involves either repairing or reconstructing the anterior cruciate ligament. With a repair, the exisiting damaged ligament is sutured (stitched) if the tear is in the middle. If the ligament has detached from the bone (avulsed) then the bony fragment is reattached.
• Surgical reconstruction of the ACL is performed using either an extraarticular technique (taking a structure that lies outside the joint capsule such as a portion of the hamstring tendon ) or an intraarticular technique (using a structure from within the knee such as part of the patellar tendon) which will replace the anterior cruciate ligament.

Who is usually considered suitable for ACL surgey?

• The competitive athlete or sports person is usually considered suitable because of the ability to adhere to a strict rehabilitation programme and the demands they will be placing on the knee following rehabilitation.
• Active people with instability of the knee and with an unwillingness to alter their lifestyle to compensate, for example where hobbies or work require strong knee joints.
• Patients whose knees lack stability in normal day to day functional situations. For example, giving way whilst climbing stairs.
• Individuals who have repeated swelling of the knee as a result of the initial injury.
• People who have tried intensive conservative rehabilitation for approx. 6 months but it has not worked.

How long will the athlete be out of action?

• This largely depends on your surgeon or physiotherapists approach to rehabilitation. Some therapists advocate an accelerated rehabilitation programme returning the athlete to full competition within 5 months, others prefer a 9 month rehabilitation period.

Disclaimer

All content within sports injury insurance is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. Sports injury insurance is not responsible or liable for any diagnosis made by a user based on the content of the injury centre. Always consult your own GP if you're in any way concerned about your health.