kreuzband_fixation2_03.jpg

Anterior Cruciate Ligament Reconstruction

What is the ACL?

The anterior cruciate ligament (ACL) is a 38mm long band of fibrous tissue that connects the femur (thigh bone) to the tibia (shin bone). Its function is to control knee stability when performing twisting and pivoting actions. The ACL is usually not required for normal daily living activities, however, it is essential in controlling the rotation forces in the knee developed during side stepping, pivoting and landing from a jump. Knees without an ACL may therefore be unable to perform activities involving speed and heights, but usually are fine with normal day-to-day activities and running straight lines.

How is it injured?

The ACL is commonly injured whilst playing ball sports or skiing in a non-contact fashion. Whilst playing ball sports upon attempting a pivot, side step or land from a jump, the knee gives way after the forces within the knee generate enough force and momentum to rupture or “tear” the ACL. When skiing, the ACL is injured when the binding fails to release as the ski twists the leg. Patients frequently hear or feel a snap, pop, or crack accompanied by pain. Swelling commonly occurs within the hour. Frequently pain is felt on the outer aspect of the knee, but rarely is the lateral collateral ligament injured significantly. The medial collateral ligament of the knee joint may however be injured resulting in severe pain and swelling about the inner side of the knee.

How do we treat an ACL injury?

The goal of treatment of an injured knee is to return the patient to their desired level of activity without risk of further injury to the joint. The environment within the knee joint, unfortunately, is not conducive to healing of the ACL. Treatment may be without surgery (conservative non-surgical treatment) or with surgery (surgical treatment). Those patients who have a ruptured ACL and are content with activities that require little in the way of side stepping (i.e. running in straight lines, cycling and swimming) may opt for conservative treatment. Surgical treatment is designed to stabilize the joint to allow activities involving side-stepping and landing from jumps at speed.

CONSERVATIVE TREATMENT

Conservative treatment is by physical therapy aimed at reducing swelling, restoring the range of motion of the knee joint and rehabilitating the full muscle power of the knee. Proprioceptive (balance and reflex) training to develop the necessary protective reflexes are required to protect the joint for normal daily living activities. This may take months to develop. As the ACL controls the joint during changes of direction, an alteration of expectations and sports to the ones involving straight line activities may be required. Social (non-competitive) sport may still be possible without instability. Skiing is possible with conservative treatment. A brace and adherence to groomed runs may be required. It is known that a small percentage of patients can return to a reasonable level of function with conservative treatment. This number, in most longer-term studies, is usually less than 50%, with some requiring a delayed reconstruction. Experienced clinical assessment is usually required to assist in the decision to manage an ACL injured knee conservatively.

SURGICAL TREATMENT

Those patients who wish to pursue competitive ball sports, or who are involved in an occupation that demands a stable knee are at risk of repeated injury resulting in tears to the menisci, damage to the articular surface, or a lack of trust in the knee. These episodes can then lead to further disability and instability as well as the possibility of degenerative arthritis over the longer term. In these patients, surgical reconstruction is recommended. Studies have shown that this is best carried out on a pain free, healthy joint with a full range of motion. This usually occurs, in most patients without significant injury to other structures in the knee, at about 4-6 weeks after the initial injury with a simple rehabilitation programme. Long term results suggest that stabilizing the joint protects menisci which reduces the risk of later osteoarthritic degenerative change. Although ACL reconstruction surgery has a high probability of returning the knee joint to near normal stability and function, the end result for the patient depends largely upon a satisfactory rehabilitation and the presence of other damage within the joint. A return to normal stability and function, which includes competitive sports, can always open the door for the risk of another injury, and this must be accepted and taken into account after a successful rehabilitation period before the decision to return to sport is made.

ABOUT THE OPERATION

The surgical procedure involves a number of steps

The aim of your operation is to reconstruct the Anterior Cruciate Ligament (ACL) to restore knee joint stability. A graft, consisting of your hamstring tendon (most often), quadracepts tendon or patella tendon, is used to replace the damaged ligament. The graft is obtained via incisions at the front of your knee. The remainder of the surgery is done arthroscopically, which means that most of the surgery has been done inside the knee with the aid of a telescope-like instrument, and without actually opening/cutting the knee joint capsule. This results in less pain and scarring within the knee post-operatively and ultimately a quicker recovery.

If a hamstring tendon is used, patients often feel a tightness or a tearing sensation at around the 3 week mark. This is normal and usually coincides with your exercises ramping up. It is normal for the hamstring to feel sore for up to 6 weeks after surgery.

The graft is fed through a tunnel drilled into the tibia (shin bone), across the knee joint and then into the femur (thigh bone). The graft is fixed at each end with button or screws and is therefore initially very strong, allowing early movement and weight bearing on the leg.

Because the ACL graft is a free graft with no blood vessels, time is needed for the graft to establish its own blood supply. The graft is strong immediately post-op, but loses strength during the first 6-8 weeks, and is at its weakest 6 weeks post-op. It is vulnerable at this time as the knee feels strong, but the graft is only beginning to establish its new blood supply. The graft does not have good blood supply until at least 10 weeks post-op. At 12 months post-op, the graft is 92% as strong as the original ACL, and this is as much strength as it develops.

Prehabilitation

There is considerable evidence to demonstrate that rehabilitation before surgery is beneficial to recovery. ACL reconstruction should be performed once the knee has recovered from the acute injury, has a full range of motion, and is pain free in order to optimise the outcome and avoid complications such as knee stiffness.

For many this may only take a few weeks, but for some it can be several months. A recent study demonstrated that a 5 week program of preoperative rehabilitation supervised by a physiotherapist improved knee related function and strength following surgery and rate of return to sports at 2 years. Quadriceps strength deficits of more than 20% before surgery are associated with persistent strength differences 2 years after surgery. A thorough prehabilitation, restoring the knee to optimal function before surgery is beneficial on every level, and will lead to a faster recovery after surgery.

Goals of prehabilitation

  1. Regain pain free full range movement

  2. Optimise muscular strength and function.

  3. Familiarise with basic post operative exercises

  4. Prevention of episodes of knee instability which may cause further damage.

Treatment guidelines

  • Initial goal is to resolve knee impairments related to swelling and ROM deficits

  • Regular icing to reduce effusion and pain

  • Commence basic VMO strengthening with use of biofeedback and range exercises

  • Once sufficient range of movement is achieved stationary exercise bike is encouraged++

  • Once swelling and ROM is achieved then progress to restoration of muscle strength with intensive muscle strength training (increasing resistance, complexity and reps), and controlled plyometric exercises (eg balance board, progressing to squats on board)

  • Running and jumping sports should be avoided due to risk of knee instability.

Rehabilitation

Stages of Rehabilitation The phases of recovery after ACL reconstruction can be considered to broadly follow 6 stages.

The goals of each stage should be achieved before progression to the next stage.

1. Prehabilitation before surgery

2. Acute Recovery

3. Muscular Control and Coordination

4. Proprioception and Agility

5. Sports Specific Skills

6. Return to Play

The following is a summary of the Rehabilitation stages after an ACL reconstruction. For a more detailed Rehabilitation guide see Rehabilitation tab at the top of the webpage.

Please be aware that this timeline is a guide only. Everybody’s rate of healing differs and you may progress faster or slower than indicated.

0-2 weeks:
Weight bearing as tolerated. Begin walking with use of the crutches, easing off them as your pain allows
Stationary bike riding as soon as able with no resistance. Begin doing only 10 minutes at a time, increasing time to 20 minutes. Ice your knee before and after.
If your surgeon has asked you to wear a splint do not bike
See your physiotherapist at 2 weeks after your knee reconstruction.

2-6 weeks:
Begin aquatic physiotherapy program designed for you by your physiotherapist.
Keep up with your rehab program as indicated by your physiotherapist.
Gently increase the resistance on the stationary bike as your pain allows.

6-12 weeks:
At 6 weeks begin swimming, use a pool buoy in between your legs and do not kick. This will begin to improve your cardiovascular fitness and upper body strength.
At 10 weeks commence swimming with a light kick.
Commence riding on the road at 8 weeks.
Commence jogging in straight lines on the flat at 10 weeks. Start with only 1km a day. Increase very gradually if no increase in pain or swelling.

12 weeks to 5 months:
Strength and agility exercises will progress
Low impact step aerobics classes can be commenced as indicated by your physiotherapist.
Commence sport specific activities guided by your physiotherapist.

5-6 months:
Return to training and participating in skill exercises.
Follow your physiotherapist’s guidelines for return to sport modifications.
Train in PEP program for warm up to reduce further ACL injury.

ACL RECONSTRUCTION EXERCISES

(Exercises to be done 3 times per day)

Stage 1 (0-2 weeks):

Goals:

  1. Control Swelling

    • REST

    • ICE – 15 to 20 minutes, 4 times per day

    • COMPRESSION – Wear tubigrip during the day

    • ELEVATE – rest as frequently as you can with your leg up on a bed/couch

  2. Mobility

    • Achieve correct gait, FWB. If pain allows without crutches

  3. Exercises

    • Achieve full passive extension (straighten out flat)

    • Achieve full flexion (bending of the knee) – may be limited by swelling

    • Active strengthening begins with static weight bearing co-contractions of quadriceps and hamstrings (emphasising VMO) and progresses to active free hamstring contractions by day 14.

Ankle Exercises
Move foot up and down and around in circles. Repeat 10 times in Each direction every hour, for the first few days.

Calf Stretch
Use towel or belt around foot to pull toes towards face. Hold for 20 seconds, relax, repeat 3 times.

Hamstring Stretch
Keeping knee and back straight, lean forward until you feel a gentle Stretch behind the knee. Hold for 20 seconds, relax, repeat 3 times.

Quad Sets/Extension


  1. Sit or lie on your back with your leg straight.

  2. Press the back of your knee downwards by tightening the muscle on the front of your thigh.

  3. Hold for 5 seconds.

  4. Repeat 3 x 10 times.

Isometric Quadriceps/Hamstring Co-Contraction (long sitting position)


  1. Sit with a rolled up towel under your knee and the thigh rolled outwards.

  2. Dig heel into bed and tighten whole thigh.

  3. Place fingers on inner thigh just above kneecap to feel quadriceps/Vastis medialis muscle contracting.

  4. Hold contraction for 5 secs, rest for a few seconds.

  5. Repeat 3 x 10 times.

  6. You can also do this sitting

Bent Leg Raise


  1. With knee bent to about 30 degrees, lift leg off bed.

  2. Keep your knee flexed at 30° throughout the exercise.

  3. Hold for 5 seconds, then relax.

  4. Repeat 3 x 10 times.

FLEXION EXERCISES

Passive Flexion in Sitting


Commence now.

  1. Wrap a towel around the ball of your foot of your operated leg.

  2. Holding the ends of the towel in your hands, gently pull the ends of the towel so that your knee bends with it.

  3. Hold at the comfortable limit of flexion for 5 seconds.

  4. Continue slowly 10 times. Gradually increase to 30 times.

Passive Flexion in Prone


Commence in 1-2 days.

  1. Lie on stomach.

  2. Place foot of unoperated leg underneath shin of operated leg.

  3. Gently assist the injured leg to bend as far as comfortable by pushing up with the unoperated leg.

  4. Hold at the limit of flexion for 5 seconds.

  5. Continue slowly for 10 – 30 times.

  6. Continue to do Passive Flexion in Sitting exercise before this one.

EXTENSION EXERCISES

Supine Hangs
Commence now.


  1. Sit or lie with foot up on a ball/bolster/rolled towel.

  2. Relax knee in straight position for 30 seconds.

  3. Continue for a total of 5 minutes.

Prone Hangs

Commence in 1-2 days. ** Only do this extension exercise. Stop doing the Supine Hangs**


  1. Lie on stomach with knee-caps over the edge of a firm bench or bed.

  2. Let operated knee gently hang over the end of bench/bed.

  3. Hang for 1 minute, lift slightly up with good leg to rest for 30 seconds.

  4. Continue for a total of 5 minutes.

Advanced Prone Hangs

Commence in 5-7 days. ** Only do this extension exercise. Stop doing the Prone Hangs**


  1. Lie on stomach with knee-caps over the edge of bench or bed.

  2. Let operated knee gently hang over the end of bench/bed.

  3. Rest the foot of your good leg over the ankle of your operated leg, to gain a greater stretch.

  4. Hold position for 1 minute, then ease pressure off by lifting good leg off for 30 seconds.

  5. Continue for a total of 5 minutes.

Patella Mobilisation

With knee straight and relaxed, gently move kneecap from side to side (A) and up and down (B).