Dr Meenakshi presents her Sports Injury Management Series – Part 4: ACL injuries

One of the most common knee injuries is the Anterior Cruciate Ligament (ACL) sprain or tear. Those who participate in high demand sports like soccer, football, tennis, badminton, squash and basketball have higher risk of injury to their ACLs. These sports involve sudden stops and changes in direction at explosive speeds.

ACL injury may require surgery to regain full function of your knee. Of course, this will depend on several factors such as the severity of your injury and the intensity of the activity.

Dr Meenakshi (P. T.) explains how we can facilitate recovery from the ACL injuries.

She breaks down her explanation in terms of –

  • symptoms,
  • causes,
  • prevention,
  • first aid,
  • basic rehab movements

The anterior cruciate ligament (ACL) is one of the tough, flexible bands of tissue that hold bones and cartilage together to help stabilize the knee joint. The ACL connects the femur (thighbone) to your tibia (shinbone).

“Cruciate” means cross shaped. The ACL and the Posterior Cruciate Ligament (PCL) cross each other inside the knee joint with the anterior cruciate ligament in front and the posterior cruciate ligament in the back. They control the forward and backward motions of your knee and resist the anterior tibial translation and rotational loads.

The ACL generates approximately 85% of the total restraining force of anterior translation. It also prevents excessive tibial medial and lateral rotation, as well as the varus and valgus stresses. It also, marginally, checks extension and hyperextension. Along with the PCL the ACL controls the instantaneous center of rotation of the knee, therefore controlling this joint’s kinematics (analysis of the relative motion between two consecutive segments of the human body and the effect on the joint of the dynamic forces at play during the movement).

About 50% of all ACL injuries occur along with damage to other structures in the knee including articular cartilage, meniscus or other ligaments.

The injured ACL injuries are considered as “sprains” and are graded according to severity:

  • Grade 1 Sprains. The ACL is mildly damaged. It has been stretched mildly but is still able to help keep the knee joint stable.
  • Grade 2 Sprains. The ACL is stretched to the point where it becomes loose. This is commonly referred to as a partial tear of the ACL.
  • Grade 3 Sprains. Commonly referred to as a complete tear of the ACL, it has been split into two pieces that makes the knee joint unstable.

It is pertinent to note that partial tears of the anterior cruciate ligament are uncommon; most ACL injuries are complete or near complete tears.


  • When you injure the ACL, you might hear a “popping” sound and you may even feel your knee collapse under you. g
  • There may be external bruising too.
  • Severe pain at the time of injury.
  • Within 24 hours, the knee will swell. If the injury is ignored, the swelling and pain may resolve on their own. But, if you attempt to return to sports or other physical activity, your knee may continue to be unstable and this will increase the risk of further damaging the meniscus which is the “cushioning” cartilage in the knee joint.
  • Loss of full range of motion of the knee joint.
  • Discomfort while walking, leave alone jogging or running or during sudden change in speed and directions of movement.


The ACL can be injured in several ways:

  • Changing direction rapidly
  • Stopping suddenly
  • Slowing down while running
  • Landing from a jump incorrectly
  • Direct contact or collision, such as a football tackle

Research studies show that female athletes have a higher incidence of ACL injury than male athletes in certain sports. It is suggested that this is due to differences in physical conditioning, muscular strength and neuromuscular control. Other reported causes include differences in pelvis and leg alignment, increased laxity in ligaments and the effects of estrogen on ligament properties.


Well, the precautions to be taken are common to all sports and exercise injuries. But it is worth reminding the reader!

  • It is essential to engage in a physical conditioning that involves appropriate strength and flexibility building movements prior to playing sports.
  • Stretch the thigh and lower leg muscles as also the tendons prior to physical activity.
  • Improve functional movement and dynamic stability of the knee joints.
  • Improve technique of sports movement or exercise like “calf raises” with external resistance in the weight training studio.

First Aid

Follow the P.R.I.C.E. drill –

  • Protect the injured part, not allowing any further damage.
  • Rest the injured part.
  • Apply ice or cold treatment for 15-20 minutes.
  • Compression: use of mild to moderate pressure to the injured area with bandages / crepe bandages is advisable.

Current international standards have replaced P.R.I.C.E. with P.O.L.I.C.E.

  • P – Protection of injured part
  • O/L – Application of Optimal load (local injury factors) / Training load

I.C.E. – as mentioned earlier (ice + compression+ elevation)

Follow up on First Aid

  • The doctors will perhaps recommend an elastic bandage or a splint or even a cast from the ankle to the groin in order to immobilize the injured knee.
  • Continued use of ice packs three or four times a day, 15 to 20 minutes per session is advisable.
  • After 72 hours, the doctors may recommend application of heat therapy, liniments or ointments.
  • Massage therapies as also hydro-therapies will be certainly enable quicker recovery.

Nutrition plays a big role in the recovery process and the injured person must consult a certified sports nutritionist.

Vitamins A, B Complex and C and the mineral Zinc as also amino acids and glucosamine (an amino sugar synthesized from glucose and glutamine) Per a study in the Journal of Orthopaedic Research, a blood platelet-enriched collagen gel can stimulate natural healing of a partial ACL tear. This encourages the cells to fill the defect and restore mechanical strength to the ligament. Unlike muscles, the tendons and ligaments get little blood flow to provide nutrients. In fact, the fluid in connective tissue is squeezed out when the muscle stretches during exercise. Nutrition filled fluid then gets absorbed when the muscle relaxes. Consuming a collagen supplement 30 to 60 minutes before exercise assures having collagen-building amino acids circulating around the damaged tissue. This has been shown to enhance healing.

Exercises to prevent injuries and strengthen the ACL

Dr Meenakshi (P. T.) recommends these rehab exercises to help recover from ACL injuries. Watch her here –

Post ACL injury rehabilitation exercises:-

  1. Quadriceps drills – isometric contraction
  2. Double leg calf raises.
  3. Bridging.
  4. Hip extension, abduction with rubber bands
  5. Lunges – be careful of your form!
  6. Double quarter squat, half squat with variable weights.
  7. Exercises for static and dynamic balance.
  8. Rebounder – jogging, static, proprioceptive.
  9. Plyometric jumps over block lateral, forward, backward.


  • It is important to avoid exercise that compresses or puts weight on your knee. Instead, the focus should be on strengthening the muscles surrounding the knee. These exercises can be done at home, ideally with the input of your physiotherapist.
  • Seek expert medical advice from your doctor or physiotherapist.