ACL Injuries & Rehab Explained

Terminal Knee Extension with Theraband demonstrated as an initial phase exercise for the rehabilitation of an ACL Injury by Fish & Field Biokineticists in Bryanston, Sandton.

Orthopaedics can be described as the branch of medicine concerned with the skeletal system (bones).  Furthermore, orthopaedics can be broken down into 2 categories:
Orthopaedic conditions such as arthritis or bursitis which affects the musculoskeletal system and are generally more chronic in nature, and
Orthopaedic injuries which are often caused by sudden trauma, such as a dislocated shoulder or a broken bone.
One of the most common orthopaedic injuries are ACL (Anterior Cruciate Ligament) injuries.

What is an ACL Injury?

The ACL is a strong ligament (ligaments attached bone to bone) on the inside of your knee joint and works together with you PCL (Posterior Cruciate Ligament) to control the back and forth motion of your knee.  It stops your tibia (shinbone) from sliding out in front of your femur (thigh bone) as well as provides rotational stability to your knee.

As explained in one of our previous articles Orthopaedic Injuries: Sprains, Strains and Dislocations, when a ligament is injured it is known as a sprain and can be graded as a grade 1, grade 2 or a grade 3 sprain – with a grade 3 sprain involving a complete tear or rupture of the ligament.  Most ACL injuries result in complete or near complete tears and seldom only partial tears.

ACL injuries most often occur during sport and fitness activities.  Movements that usually elicit an ACL injury include:

  • Suddenly slowing down and changing direction
  • Having your foot firmly planted and then pivoting your knee
  • Stopping suddenly
  • A direct blow to the knee or a collision
  • Jumping and landing incorrectly

Most people will hear a ‘popping’ or ‘snapping’ sound when injuring their ACL.  Other symptoms include your knee giving in, pain and swelling, instability in the knee joint, loss of range of motion and discomfort while walking.

Treatment of ACL Injuries

Depending on the severity of the injury you might decide to make use of the RICE (rest, ice, compression and elevation) treatment or to see your doctor.  Your doctor will ask you about symptoms and the nature of the injury as well as examine your knee, comparing it to the non-injured knee.  This will include assessing swelling, tenderness and movement in the joint.  Should the doctor be unable to make a diagnosis on examination alone, you might be asked to go for an X-ray, MRI or ultrasound scan.

Treatment for an ACL injury depends on the extend of the injury as well as the goals/lifestyle of the individual.  Should the ACL injury be accompanied by other structures in the knee being injured or should the individual participate in more competitive sporting activities, treatment would most likely include surgery.  Whereas conservative physical rehabilitation might be suggested in lone ACL injuries or ACL injuries in individuals with a less active lifestyle.

ACL Surgery and Rehabilitation

Surgery:  During ACL reconstructive surgery the damaged ligament is removed and is replaced with a tendon (for example from the hamstrings, quad or patellar (knee) tendon).  Post-surgery you will still need to undergo conservative physical rehabilitation.

Physical Rehabilitation:  Physical rehabilitation involves performing a series of rehabilitative exercises that is aimed at reducing pain and swelling, regaining full range of motion, increasing strength in the muscles supporting the knee and finally returning to all activities of daily living and sports.  Initially rehabilitation exercises would take place under constant supervision of a biokineticist, with 2 – 3 sessions a week being recommended.  The biokineticist would make sure that the exercises are performed correctly so that no re-injury occurs.  The individual will also be asked to perform some of these exercises at home.

Rehabilitation can take anywhere from 6 months to a year, depending on the initial severity of the injury, condition of individual prior to the injury, consistency of the rehabilitation program and the individual’s personal goals.

Initial phase exercises

Knee Extension with Rolled Up Towel

Knee Extension with Rolled Up Towel demonstrated as an initial phase exercise for the rehabilitation of an ACL Injury by Fish & Field Biokineticists in Bryanston, Sandton.

Lying on your back, legs straight with a rolled-up towel place under your ankle.  The aim is to relax your leg as much as possible so that your knee can go into extension (your leg straightening out).  Hold position for 30 seconds, repeat.

Quad Contraction Sets

Quad Contraction Sets demonstrated as an initial phase exercise for the rehabilitation of an ACL Injury by Fish & Field Biokineticists in Bryanston, Sandton.

Place a small half deflated ball or rolled-up towel under your knee.  Push down with your knee onto the ball or towel, toes pointing up towards the ceiling.  Hold contraction for 5 – 10 seconds and repeat 10 times.

Slightly progressed exercises

Straight Leg Raise (SLR)

Lying down on your back, keep one knee bent with the other leg straight. Then lift the straight leg up from the floor to the height of the bent knee.  Initially one would do these with toes pointing up towards the ceiling and can progress to rotating your toes out to the side.  Do 3 sets of 5 – 10 repetitions.

Terminal Knee Extension with Theraband

Tie the two ends of the theraband together, placing it around your knee and a pole/rail/burglar bar.  Your starting position is with your knee bent (theraband should already be tight).  Then straighten out your knee against the resistance of the theraband, return to starting position in a controlled manner.  Do 3 sets of 10 repetitions.

*Above all, make sure to consult your doctor or biokineticist before starting any new exercises

ACL Rehabilitation through a biokinetic program

At Fish and Field Biokineticists we provide both land-based rehabilitation as well as aqua therapy rehabilitation.  Aqua therapy rehabilitation is a great place for individuals to start their rehab pre and post ACL reconstructive surgery as the water provides a safe and supportive environment.  The water assists with reducing pain and swelling due to the heat and hydrostatic pressure of the water, this in turn assists with achieving full range of motion with greater ease.  Balance and proprioceptive exercises can get started earlier as the water provides for longer reaction time. And strength training comes naturally due to the viscosity of the water.  Initial rehab is started in deeper water to reduce the amount of weight placed on the knee joint. One then progresses to shallower water to provide more weight-bearing exercises, with final rehabilitation being performed on land.

Fish and Field Biokineticsts rehabilitation program in heated pool to practice aqua-therapy

For any queries or more information please feel free to contact us on


OrthoInfo. 1995 – 2020.  Anterior Cruciate Ligament (ACL) Injuries.  Available at:–conditions/anterior-cruciate-ligament-acl-injuries/.  [Accessed 30/03/2020].

MayoClinic.  1998 – 2020.  ACL Injury.  Available at:  [Accessed 30/03/2020].

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