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Anterior cruciate ligament (ACL) reconstruction rehabilitation

Patient information A-Z

A guide to rehabilitation following anterior cruciate ligament (ACL) reconstruction surgery

Introduction

(ACL) reconstruction is an operation to replace a torn anterior cruciate ligament and restore stability to the knee joint.

Anatomy of the knee joint

Diagram of a knee joint, labelled: anterior cruciate ligament, lateral collateral ligament, lateral meniscus, posterior cruciate ligament, medial collateral ligament, medial meniscus

An ACL injury typically occurs in a non-contact twisting movement, often during a sporting activity. ACL injuries can occur in isolation or with injuries to other structures in the knee such as the medial collateral ligament (MCL) and / or the medial meniscus (cartilage).

The aim of ACL reconstruction surgery is to restore the directional stability of the knee and to improve function. Rehabilitation is vital to ensure good functional outcomes following ACL reconstruction. Research shows that greater quadriceps (thigh muscle) strength is associated with better self-reported knee function and successful return to normal activities and sport.

This guide explains the rehabilitation process and gives exercises to perform following ACL reconstruction surgery. If you have had a repair of other structures in the knee such as the meniscus, the post-operative protocol may differ slightly, and progression is usually expected to be somewhat slower. If this is the case, the physiotherapist on the ward will explain this to you.

Walking after the operation

You are usually able to take as much weight through your operated leg as pain allows (unless otherwise advised by your consultant or physiotherapist). You will be given elbow crutches. Use these for around the first two weeks, or longer if your knee feels weak or you lack confidence.

Swelling and pain

Some swelling and pain is to be expected for the first few days to a week after your operation. If the knee is swollen, rest with your leg elevated and use ice (be sure not to get the wounds wet whilst using ice; wrap the ice in a towel). Pain levels are usually quite variable in your rehabilitation journey, and this is normal. Low-level pain and discomfort are to be expected and are normal.

Week 1 targets

Typical progress/targets:

  • Regain active quadriceps control.
  • Decrease swelling in the knee.
  • Ensure adequate pain control.
  • Restore knee cap mobility.
  • Aim to achieve full knee extension (straightening).
  • Be able to perform a straight leg raise with no lag (no bending of the knee).
  • Progress flexion (bending) aiming for at least 45 degrees.
  • Restore normal walking pattern.

Week 1 exercises

Aim to perform these regularly, starting with little and often and gradually building up as pain allows. The suggested number of repetitions and sets is a guide and will depend on where you are in your own individual rehabilitation. Start with lower numbers and build up gradually.

Ankle pumps
Illustration of legs stretched out in front. One ankle bending back towards body and the other bending forwards away from body.
Ankle pumps This exercise is designed to help with circulation. Lying or sitting (on the bed of sofa is fine), move your ankles up and down. This should be performed regularly – at least every couple of hours. Repeat 8 to 15 times.
Static quads/knee extension
Illustration of one legs laid on the floor; one straight and one bent at the knee
Lying on your back, tighten your thigh muscles to push the back of your knee down into the bed whilst pulling your toes towards you. Keep the knee straight. Hold for 5 to 10 seconds. Repeat 6 to 12 times. 2 to 3 sets. Little and often throughout the day.
Knee flexion
Illustration of person lying on their back with one leg bent at the knee and the other leg straight
Lying on your back, bend and straighten your leg. Gradually increase the amount of bend as you are able. Repeat 8 to 15 times. Little and often throughout the day.
Isometric hamstrings
Illustration of a person laying on their back with one leg bent at the knee and other leg bent slightly, at about 30 degrees
Lie on your back with your knee bent to about 30 degrees. Pull the heel into the floor / bed, tightening the muscles on the back of the thigh. Hold for 5 to 10 seconds. Repeat 6 to 12 times. 2 to 3 sets. Little and often throughout the day.
Straight leg raise
Illustration of a person laying on their back with one leg bent at the knee and one leg raised up straight.
Lie on your back. Tighten your thigh muscles. Keeping the leg (?) straight, raise the whole leg off the bed and lower. Repeat 6 to 12 times. 2 to 3 sets. Little and often throughout the day.
Standing knee bends
Illustration of a person standing, holding onto the back of a chair with one leg bent at the knee behind them
Standing, holding onto a support. Bend your operated knee and take the heel towards your buttocks. Return to the starting position. Repeat 6 to 12 times. 2 to 3 sets. Little and often throughout the day.
Knee extension
Illustration of a person sitting on a chair with one leg out straight resting on a stool
Resting in extension Spend time with your knee out straight. Sit with your foot up on a chair / stool allowing your knee to hang into extension. 3 to 5 minutes. Little and often throughout the day.

If you do not have full knee extension, use the heel prop exercise (shown below) as pain allows, making sure that you do not force the movement.

Note: In the case of increasing knee temperature, swelling or pain as a reaction to any of these mobilisation exercises, ease off the exercise causing the discomfort. Use ice and elevation and discuss with your physiotherapist at your outpatient appointment.

Week 2 to 6 targets

Typical progress / targets:

  • Wean yourself off crutches if you can achieve a good straight leg raise.
  • Maintain full knee extension.
  • Gradual increase in range of motion within limits of pain.
  • Aim for 90 degrees of flexion (bending) by the end of week 2.
  • Aim for 120 degrees of flexion (bending) by the end of week 4.
  • Restore proprioception (balance) and neuromuscular control.

Again, the suggested number of repetitions and sets is a guide and will depend on where you are in your own individual rehabilitation. Start with lower numbers and build gradually. The aim at this point is to exercise to the point where muscles feel tired/fatigued, to ensure muscle strength increases over a training period.

Week 2 to 6 exercises

With all of these exercises, start with lower numbers and build gradually. You should aim to make the muscles feel achy/tired by the end of the sets.

Prone knee bends
Illustration of a person laying face down with a towel around the ankle, pulling foot towards back
Lie on your front. Place a towel or belt around the ankle and bend the knee as far as comfortable to improve flexion. Do not force it, stretch as far as comfortable. Hold for 8 to 15 seconds. 2 to 3 sets.
Bridge
Illustration of a person laying down on their back with the knees bent whilst lifting their bottom and lower back off the floor
Lie on your back with your knees bent. Lift your bottom off the floor as high as you are able, then lower. Repeat 8 to 12 times. 2-3 sets.
Squats/wall squats
Illustrations of a person standing with feet shoulder-width apart while bending the knees and arms out in front, and a person with their back against a wall, arms by their side and knees bent.
You can train in a range of motion of 0-60 degrees of flexion during the squat in the first 3-4 weeks, then gradually increase the depth as able. Stand with your feet about shoulder-width apart, bend your knees to perform a squat and extend the knees to stand tall again. Aim to keep equal weight bearing between legs. With your feet around 20cm from the wall and perform a wall squat if you pre can stand with your back on the wall. Repeat 8 to 12 times. 2 to 3 sets.
Hamstring curls
Illustration of a person laying face down whilst bending their leg at the knee upwards at a 90 degree angle
Lie on your front. Bend the operated knee to around 90 degrees. Lift the leg up and lower. Repeat 8 to12 times. 2 to 3 sets.
Sit to stand
Illustration of a person lowering themselves down onto a stool
Sitting on a chair, feet shoulder-width apart. Stand up and sit down again. Repeat 8 to 12 times. 2 to 3 sets.
Calf stretches
Illustration of a person holding onto the back of a chair with one leg bent at the knee in front and the other leg straightened behind
Hands on a wall or holding on to a support, place one foot in front of the other, with the leg to be stretched behind. Keep the heel on the ground and the back knee straight, bend the front knee to feel a stretch in the calf. Hold for 8 to15 seconds. 2 to 3 sets.
Heel raises
Illustration of a person standing whilst holding onto the back of a chair, pushing up on their toes
Standing, holding a support, push up onto your toes and lower again. Repeat 8 to 12 times. 2 to 3 sets.
Seated flexion
Illustration of a person sitting on a chair, bending their knee to move the foot underneath the chair
Sitting on a chair, bend the knee to move the foot underneath the chair to work on knee flexion. Hold for 5 to 8 seconds. Repeat 8 to 10 times. 2 to 3 sets.

Week 6-12

The graft is still healing to the bone at this time. Therefore, you should continue to take care to avoid falls. You would usually have seen a physiotherapist by this point who will be able to assist in the progression of exercises. It may be that you are referred to an ACL class.

Typical progress / targets:

  • Increase leg strength (knee and hip).
  • Improve balance and coordination.
  • Be able to perform a single leg dip with good control.

Your exercise program should include:

  • Leg press
  • Leg curl
  • Squats
  • Calf raises
  • Hip extensions, bridges, single leg bridges
  • Hip abductions
  • 1 leg stand balance work
  • Wobble board for improving balance
  • Stairs / step ups
  • Static bike, rower, stepper, cross trainer
  • Lunges
  • 1 leg dips

Precautions:

Progress your activities gradually and continue to avoid any running, pivoting, jumping or cutting (changing direction quickly).

Open chain knee extension and graft type

Hamstring graft

  • If you had a hamstring graft, the current evidence suggests you should not perform open chain exercises with resistance (leg extensions) until 12 weeks.
  • In a hamstring graft reconstruction, open chain exercises (leg extensions) can be performed without resistance from week 4 in a range of motion of 90 to 45 degrees.
  • The range of motion in the leg extension without resistance can be increased as follows:
    • Week 5: 90 to 30 degrees
    • Week 6: 90 to 20 degrees
    • Week 7: 90 to 10 degrees
    • Week 8: full range of motion 90 to 0 degrees (full extension)

Patella graft

  • If you had a patella tendon graft, the current evidence suggests open chain exercises with resistance (leg extensions) can be performed from 4 weeks in a range of motion of 90 degrees to 45 degrees.
  • The range of motion in the leg extension with resistance can be increased as follows:
    • Week 5: 90 to 30 degrees
    • Week 6: 90 to 20 degrees
    • Week 7: 90 to 10 degrees
    • Week 8: full range of motion 90 to 0 degrees (full extension)
Illustration of a person sitting in a chair with one leg extended out at a 90 degree angle and the other at full extension (0 degrees). A line demonstrates a 45 degree angle.

Week 12 onwards

Evidence supports criteria-based progression rather than a strict time-based progression. This means that you should discuss your progression through these activities with your physiotherapist. It is important that you feel you have developed good leg strength and stability and that you only progress when you feel ready.

Provided you have good single leg dip control, you may look to start jogging in a straight line at three months after surgery. For some, this may take a little longer as everyone progresses differently.

Functional program:

  • Leg extensions with resistance (both hamstring and patella tendon grafts)
  • Skipping
  • Light running initially in a straight line
  • As confidence grows figure of 8 running
  • Change of direction
  • Curves / cutting (changing direction quickly) / zig zags
  • Jumping
  • Hopping
  • Faster running, sprinting

Six months onwards and returning to normal sporting activities

Research indicates that the decision around return to sport should be based on meeting key performance criteria rather than based on time frames.

The earliest that you are likely to be able to return to sport is six months. Evidence shows that the risk of injury when returning to sport is significantly reduced when return-to-sport criteria are met and by waiting until nine months after your operation.

It is important to only progress your rehabilitation and look to start returning to sporting based activities when you feel ready. Evidence shows that there are psychological aspects of the rehabilitation to consider (as with any injury). It is important to understand that the psychological factors of rehabilitation are normal and will differ from person to person depending on their progress.

Return-to-sport performance criteria often include:

  • No giving way or fear of giving way during sporting activities
  • Quadriceps and hamstring strength within 10% of the uninjured side
  • Hop tests with no more than 10% difference between sides
  • Agility drill (T–Test)
  • Psychologically ready (use of psychological questionnaire such as Tampa Scale-11, ACL-Return to Sport after Injury Scale or Knee Self-Efficacy Scale)

Progression at this stage of rehabilitation can be discussed with your outpatient physiotherapist.

The information in this leaflet guides you through the initial six weeks and onwards following ACL reconstruction surgery.

The timescales described are for guidance only. The exact progress will vary depending on the individual.

You will normally see one of the orthopaedic consultant’s team in an outpatient appointment a number of weeks after the operation. The physiotherapist on the ward will refer you to your local physiotherapy outpatients department for ongoing rehabilitation.

The information in this booklet follows recommended guidelines based on the available evidence and literature.

Other useful resources

Evidence based ACL rehabilitation advice videos:

  • YouTube: Physiotutors ACL Rehab Phase 1
  • YouTube: Physiotutors ACL Rehab Phase 2

References

Grindem, H., Snyder-Mackler, L., Moksnes, H., Engebretsen, L., & Risberg, M. A. (2016). Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. British journal of sports medicine, 50(13), 804-808.

Van Melick, N., Van Cingel, R., Brooijmans, F., Neeter, C., Van Tienen, T., Hullegie, W., & Nijhuis-van Der Sanden, M. (2016). Evidence-based clinical practice update: Practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. British Journal of Sports Medicine, 50(24), 1506-1515.

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