Anterior Cruciate Ligament (ACL) Reconstruction
Five-phase pathway after ACL reconstruction in the skeletally mature patient: from early post-operative recovery to return to team, with objective criteria between phases.
Return to pivoting sport: not before 9 months, typically 9-12 months
This protocol is part of the post-operative pathway and must be adapted to the surgeon’s instructions and to the individual clinical response.
These documents are protocol templates for information and education only: they do not replace the rehabilitation prescription for the individual case. Timing, loading and progressions must always be adapted to the patient, the lesion pattern, the surgical technique used and the clinical course, in collaboration between orthopaedic surgeon, physiotherapist and, where appropriate, physiatrist. Progression is driven by objective criteria, not by the calendar alone.
At a glance
- Weight bearing
- Progressive weight bearing as tolerated from day one, unless the surgeon indicates otherwise (associated lesions, specific fixation).
- Brace
- Not routinely required; when prescribed, usually locked in extension for walking in the first weeks.
- ROM
- Full extension (0°) is the absolute priority; 90° flexion within 2 weeks, 125°+ within 6-8 weeks.
- Straight-line running
- Not before month 3, and only with full ROM, no effusion and quadriceps strength ≥70-80% of the contralateral side.
- Daily activities
- Sedentary work after 7-10 days; driving at 30-45 days; swimming and showering after wound healing (15-20 days).
- Return to sport
- Pivoting sport not before 9 months, with the full test battery passed (LSI ≥90%).
- Day 1Full extension and quadriceps contraction
- 2 weeks90° flexion, walking without crutches
- 6 weeksFull ROM, bike with resistance
- 3 monthsStart straight-line running
- 6 monthsPlyometrics, agility, strength ≥90%
- 9-12 monthsReturn to pivoting sport
The anterior cruciate ligament prevents anterior translation of the tibia on the femur and controls rotation. After reconstruction, the graft undergoes a biological process of integration and revascularisation that takes time and cannot be accelerated: rehabilitation supports it, it does not force it.
Loading timeline
Step by step
Each phase lists the goals, what to do and the exercises for that exact moment: do not anticipate them. Dosage is indicative and must be adapted by your physiotherapist.
Before surgery — Preoperative preparation (prehabilitation)
Indicatively 2-6 weeks before surgery, when the knee allows it: duration and need depend on the clinical picture, there is no mandatory minimum.
When it applies
- •When the clinical picture and surgical timing allow, the preoperative phase is an integral part of the pathway, not a side note.
- •It is particularly useful with a still swollen or stiff knee, an extension deficit or quadriceps inhibition after the injury.
- •It is carried out with the physiotherapist, with an agreed daily home programme.
Goals before surgery
- •Full extension, or symmetrical to the uninjured knee.
- •Near-full flexion.
- •Minimal effusion (a "dry" knee).
- •Walking without significant limp, ideally without crutches.
- •Good voluntary quadriceps control and activation, with no extension lag.
- •Strength recovery compatible with the clinical picture of the injured limb.
- •Education on brace, crutches, allowed weight bearing and the early post-operative phases.
Activities
- •Effusion and pain control (ice, elevation, load management).
- •Practical education on brace, crutches, allowed weight bearing and the goals of the first weeks.
- •Daily home programme, alongside physiotherapy sessions.
Preoperative exercises
Quadriceps isometric contraction (quad set)
- •Lying down, knee straight in a neutral position on the surface; if proprioceptive feedback helps, place a small rolled towel under the knee.
- •Contract the quadriceps pushing the back of the knee toward the surface, hold, then release slowly.
- •Aim for a visible, global quadriceps contraction, without breath holding.
Dosage: Indicative: 10 contractions of 5 seconds, 2-3 times a day. To be adapted with the physiotherapist.
Straight leg raise (only if there is no extension lag)
- •First contract the quadriceps and lock the knee in full extension.
- •Lift the straight leg about 30 cm keeping the knee straight, then lower it slowly.
- •If the knee drops into flexion during the lift (extension lag), stop and work on quad sets first.
Dosage: Indicative: 2-3 sets of 8-10 repetitions. To be adapted with the physiotherapist.
Extension recovery with the heel supported
- •Lying down, rest only the heel on a low support leaving the knee unsupported.
- •Let the knee drop under gravity with the thigh relaxed; a gentle quadriceps contraction can be added.
- •Do not force and do not push abruptly on the knee: extension returns with time and relaxation.
Dosage: Indicative: 3-5 minutes, several times a day if well tolerated.
Heel slides / active-assisted flexion
- •Lying down, slide the heel toward the buttock keeping the foot in contact with the surface.
- •You may assist with your hands or a towel around the leg, staying within the pain-free range.
- •Return slowly to the start position, regaining full extension.
Dosage: Indicative: 10-15 repetitions, 2-3 times a day.
Mini squat or sit-to-stand within the tolerated range
- •Standing, bend the knees only within the pain-free range (usually within 45-60°), keeping the knee aligned over the foot.
- •Alternatively, stand up and sit down from a comfortable chair height, sharing weight between both legs.
- •Avoid knee valgus collapse and trunk twisting.
Dosage: Indicative: 2-3 sets of 8-12 repetitions, on alternate days or as advised.
Bridge
- •Supine, knees bent and feet hip-width apart on the floor.
- •Lift the pelvis squeezing the glutes, without arching the back, then lower slowly.
Dosage: Indicative: 2-3 sets of 10-12 repetitions.
Single-leg balance (only if safe)
- •Standing near a support, load one leg keeping the knee slightly flexed and the pelvis level.
- •Stop if pain, giving-way sensation or instability appear.
Dosage: Indicative: 3-5 holds of 20-30 seconds per side.
Stationary bike
- •To be introduced when range of motion and pain allow: raise the saddle if flexion is still limited.
- •Continuous pedalling at low resistance, pain-free and without increased swelling in the following hours.
Dosage: Indicative: 10-20 minutes, as tolerated.
Crutch and weight-bearing training
- •Try the crutches before surgery, with correct height and the weight-bearing status set by the surgeon.
- •Practise on level ground, stairs and the entrance to your home, with someone assisting.
- •Also practise sitting, standing and moving in the bathroom while respecting the planned loading restrictions.
Dosage: At least one training session before admission; repeat until the technique is safe.
Readiness criteria for surgery
- ☐Full or symmetrical extension and near-full flexion.
- ☐A dry knee, or a stable minimal effusion.
- ☐Smooth gait, without antalgic limp.
- ☐Effective quadriceps contraction, with no extension lag on straight leg raise.
- ☐The young patient and family can use crutches and brace and understand the first post-operative weeks.
When surgery must not be delayed
- •Locked knee or bucket-handle meniscal tear: surgery should not be postponed to complete weeks of prehabilitation.
- •Associated lesions needing timely treatment (repairable chondral or osteochondral lesions, multiligament injuries, fractures).
- •Repeated giving-way episodes: not an automatic indication, but they may make it appropriate to bring forward the surgical decision, especially if they limit daily life or expose the knee to new meniscal or chondral injuries.
What to prepare at home and school
- •Organise movement at home: clear pathways, remove rugs, keep useful items within reach.
- •Prepare ice, a support for the heel, comfortable clothing and crutches already adjusted.
- •Inform school or the sports club: plan the absence, temporary exemption and gradual return.
- •Agree the first post-operative physiotherapy session in advance.
Preoperative preparation may improve pre-surgical strength and function and support early recovery after reconstruction. It is not a guarantee of the final outcome: the post-operative pathway remains decisive. Dosages and duration are indicative and must be adapted by the physiotherapist.
Phase 1 — Early post-operative recovery
Indicative timing: Weeks 0-2
The time window is indicative: progression depends on the criteria listed below, not on the calendar.
Goals
- •Achieve and maintain full knee extension
- •Reduce and control joint effusion
- •Restore voluntary quadriceps activation
What to do
- •Quadriceps isometrics in full extension, straight leg raise without extension lag
- •Patellar mobilisations, cryotherapy and compression, elevation
- •Correct gait with two crutches, progressive weight bearing as tolerated
- •Active-assisted flexion up to 90°, ankle mobility
Restrictions and precautions
- •Do not force flexion beyond 90° in this phase
- •Avoid prolonged standing and direct skin contact with ice
- •Keep the wound dry for 15-20 days
Exercises for this phase
1. Quadriceps isometric contraction (quad set)From day 1
- •Lie on your back with the leg straight and a rolled towel under the ankle.
- •Push the knee down by tightening the thigh, as if flattening the bed.
- •The heel lifts slightly: that means you are reaching full extension.
Dosage: 10 contractions of 5 seconds, 4-6 times a day
2. Straight-leg raiseFrom day 1-2
- •Lying on your back, first tighten the thigh until the knee locks straight.
- •Lift the straight leg about 30 cm, hold 3 seconds and lower slowly.
- •If the knee bends while lifting, the quadriceps is not ready yet: go back to quad sets.
Dosage: 3 sets of 10, twice a day
Ready for the next phase when
- ☐Passive extension 0°, passive flexion 90°
- ☐Mild to moderate effusion in the anterior/medial compartment
- ☐Ability to hold the knee extended against gravity (no extension lag)
Note for the physiotherapist
Early full extension is the single strongest predictor of good functional outcome: regain it now, not later. Quadriceps control (quad set without lag) precedes any loading progression.
Phase 2 — Strength and neuromuscular control
Indicative timing: Weeks 2-12
The time window is indicative: progression depends on the criteria listed below, not on the calendar.
Goals
- •Regain single-leg balance
- •Restore thigh and posterior chain strength
- •Restore full range of motion
What to do
- •Straight leg raise in 4 directions, hamstring stretching, patellar mobilisations
- •Closed kinetic chain: isometric mini-squat, protected-range leg press, progression bilateral squat → goblet → split squat → lunge → step down → single leg squat
- •Leg curl for hamstrings, calf strengthening, ankle mobility work
- •Proprioception (wobble board, unstable surfaces), slow cycling with high saddle, walking in water
Restrictions and precautions
- •Progress only if the knee stays dry and pain-free over the following 24 hours
- •Caution with open kinetic chain in the 0-30° arc in the early weeks
Exercises for this phase
3. Global quadriceps recoveryWeeks 1-6
- •Sitting with a pillow under the slightly bent knee.
- •Extend the knee by pushing the heel forward, keeping the thigh on the pillow.
- •Aim for a full, even contraction of the whole thigh: isolating a single portion of the muscle is not useful.
Dosage: 3 sets of 12, once or twice a day
4. Mini-squat 0-45°From the full weight-bearing phase
- •Standing, feet hip-width apart, weight evenly distributed.
- •Bend the knees to about 45°, keeping the knees aligned over the feet.
- •Rise by pushing through the heels, without letting the knee collapse inwards.
Dosage: 3 sets of 12, 3-4 times a week
5. Glute bridgeFrom week 2
- •Lie on your back, knees bent, feet flat on the floor.
- •Lift the pelvis by squeezing the glutes until shoulders, hip and knee are aligned.
- •Lower slowly without arching the back.
Dosage: 3 sets of 12-15, on alternate days
Ready for the next phase when
- ☐Passive extension 0°, passive flexion 125°+
- ☐No effusion
- ☐Stable single-leg balance and single leg squat without dynamic valgus
- ☐Documented progression of quadriceps strength (dynamometry or comparative isometric testing); thigh circumference, if measured in a standardised way, is only a complementary datum
Note for the physiotherapist
Dynamic valgus (femoral internal rotation, knee adduction, ankle eversion) is a re-injury risk factor: assess it with 2D video during single leg squat and drop vertical jump and correct it before adding plyometric load.
Phase 3 — Running, agility and jumping
Indicative timing: Months 3-6
The time window is indicative: progression depends on the criteria listed below, not on the calendar.
Goals
- •Excellent jump, landing and rebound control
- •Agility programme and cardiovascular reconditioning
- •Full recovery of leg and core strength
What to do
- •Slow straight-line running, then figure-of-8 with progressively tighter radius
- •Guided, progressive plyometrics: pool → trampoline → sand → grass → hard surface
- •Agility and deceleration drills with focus on landing technique
- •Continued gym strengthening and neuromuscular work
Restrictions and precautions
- •No contact, no pivoting in uncontrolled situations
- •Pay attention to surface type and footwear
Exercises for this phase
6. Controlled step-downStrength phase (from month 3)
- •Stand on a 15-20 cm step on the operated leg.
- •Lower slowly with the other foot, touching the floor with the heel, over 3 seconds.
- •The standing knee must stay aligned over the foot: if it collapses inwards, lower the step.
Dosage: 3 sets of 8-10 per side, 3 times a week
7. Single-leg balanceFrom the full weight-bearing phase
- •Stand on one leg, knee slightly bent, looking ahead.
- •Progress: eyes open → eyes closed → soft surface → catching a ball.
- •The pelvis must stay level: if it drops on one side, the gluteus medius is weak.
Dosage: 3 x 30 seconds per side, daily
Ready for the next phase when
- ☐Confidence and correct landing technique, without dynamic valgus
- ☐Running and plyometrics tolerated without pain or effusion over 24-48 hours
- ☐Documented progression of quadriceps and hamstring strength; maximal hop testing belongs to the later sport-specific phases
Note for the physiotherapist
The keyword is technique: quality of deceleration and landing before volume and intensity. Isokinetic testing at the end of this phase documents the residual deficit.
Phase 4 — Return to team and sport
Indicative timing: From month 6-9
The time window is indicative: progression depends on the criteria listed below, not on the calendar.
Goals
- •Stable, solid knee with excellent neuromuscular control
- •Confident athlete ready to return
- •Recovery of sport-specific technical skills
What to do
- •Individualised programme supervised by a coach or physiotherapist experienced in injury recovery
- •Progressive simulation of sport-specific gestures (shooting, serving, ball skills)
- •Partial team training, then full training before match play
- •Isokinetic test before the outpatient review (around 6-7 months), brought to the appointment
Restrictions and precautions
- •No competitive match play before the full test battery is passed and 9 months have elapsed
Exercises for this phase
8. Progressive plyometricsImpact phase
- •Start with two-foot hops on the spot, landing softly with bent knees.
- •Progress to front-back and lateral hops, then single-leg.
- •Landings must be silent: noise means insufficient shock absorption.
Dosage: 2-3 sets of 10-20 contacts, 2-3 times a week
Ready for the next phase when
- ☐Isokinetic muscle deficit no greater than 10% versus the healthy side
- ☐4 hop test battery with LSI ≥90% (reference value, not binding on its own)
- ☐IKDC ≥90 and adequate psychological readiness to return (also assessed with ACL-RSI, read as a trend over time rather than a mandatory threshold)
- ☐Full team training without symptoms
Note for the physiotherapist
Clearance is multifactorial: clinical assessment + scores (IKDC, ACL-RSI, Melbourne ACL RTS score) + functional tests. Low or worsening psychological readiness is associated with failure to return and with re-injury even when strength has recovered: interpret it in context and over time, not as a single cut-off.
Phase 5 — Re-injury prevention
Indicative timing: Ongoing, at least a 6-week structured programme
The time window is indicative: progression depends on the criteria listed below, not on the calendar.
Goals
- •Improve neuromuscular control in running, sprinting, cutting and jumping
- •Maintain balance between muscle groups
- •Make the programme part of the training routine
What to do
- •FIFA 11+ programme (adult or kids version) built into the team warm-up
- •Balance, endurance and strength work several times a week
- •Education of athlete, coach and strength coach
Exercises for this phase
9. Agility and change of directionPre-return-to-sport phase
- •Shuttle runs, figure-of-8, cone slaloms: wide turns first, then sharper cuts.
- •Add unanticipated (cued) direction changes only at the end.
- •No drill should be performed with pain or a feeling of an unsafe knee.
Dosage: 2 sessions a week, within training
10. Low-impact conditioningAll intermediate phases
- •Stationary bike with high saddle and minimal resistance, swimming (avoiding breaststroke early), elliptical.
- •These maintain general fitness without compressing the repaired area.
- •The rule is always the same: no swelling the next day.
Dosage: 20-30 minutes, 3-5 times a week
Ready for the next phase when
- ☐Prevention programme performed consistently at least 2-3 times a week
- ☐No dynamic valgus at periodic checks
- ☐Strength symmetry maintained over time
Note for the physiotherapist
About 75% of ACL injuries occur without direct contact and a substantial proportion is preventable. Growing athletes and female athletes carry a clearly higher risk for the same activity.
If symptoms appear after a progression
If persistent pain, effusion or swelling, or loss of movement appears after moving to a new phase or increasing load, temporarily reduce load and volume and have the situation reassessed by the surgeon or physiotherapist before progressing again. This document is informative for families and physiotherapists and does not replace individual clinical assessment.
Return to sport / full activity
Pivoting and contact sport: not before 9 months post-op, typically 9-12 months.
- ☐4 hop test battery (single, triple, crossover, 6 m timed) with LSI ≥90%
- ☐Isokinetic quadriceps and hamstring strength with LSI ≥90% (deficit ≤10%)
- ☐Subjective IKDC ≥90
- ☐Adequate psychological readiness to return, assessed clinically and over time (ACL-RSI may be used as a reference, not as a binding cut-off)
- ☐No effusion, full and symmetrical ROM
- ☐Full team training without symptoms for at least 2-4 weeks
In published cohorts, each month of delay up to month 9 is associated with a lower re-injury risk: this is an observed association, not an individual guarantee. In patients under 20-25 years the risk of graft or contralateral rupture remains high: continuing the prevention programme after return is an integral part of the protocol. The Limb Symmetry Index has known limitations: on its own it is not sufficient, because the uninjured side may also be deconditioned; it should be combined with absolute strength values, movement quality and sport-specific demands.
Red flags: stop and contact us
- •Effusion that returns or increases after sessions: a sign of overload, reduce load and reassess
- •Loss of full extension or new extension lag
- •Joint locking or painful catching (suspected associated meniscal tear or cyclops lesion)
- •Persistent and worsening anterior knee pain
- •Subjective giving way or instability
- •Fever, redness, warmth or wound discharge (suspected infection: contact us immediately)
- •Calf pain with asymmetric swelling (suspected deep vein thrombosis: urgent assessment)
Written and reviewed by Dott. Daniele Priano, Paediatric Orthopaedics. Last review: August 2026.
Timings are indicative: progression depends on clinical and functional criteria and on the surgeon’s indications.
Frequent questions
Why wait 9 months if I already feel fine at 5?
Subjective feeling improves long before the biological strength of the graft, which keeps remodelling for months. In the Delaware-Oslo cohort re-injury risk fell progressively for each month of delay up to nine, and those who met return-to-sport criteria had roughly an 84% risk reduction.
Do I need a brace?
Not routinely: the literature shows no benefit of rigid bracing after isolated ACL reconstruction. It is prescribed in selected cases, for example with associated lesions or fixation requiring protection.
When can I drive?
Usually between 30 and 45 days, once ROM is adequate, crutches are no longer needed and braking reaction time is normal. Times are usually longer for the right leg than for the left with an automatic gearbox.
Is swelling in the evening normal?
Mild evening swelling in the first weeks is common. It becomes a warning sign when it increases day by day, appears after every session, or does not settle within 24-48 hours with ice and elevation: in that case the weekly load is excessive and should be reduced by one level.
Can I do physiotherapy only once a week?
The physiotherapy session is for setting up, correcting and progressing the programme. The result, however, depends on the exercises performed at home every day: a short daily home programme is worth more than an isolated weekly session.
In-depth content (full introduction, technique comparison, FAQ, references) at ortopediaevolutiva.com/en/rehabilitation/acl-reconstruction
Anterior Cruciate Ligament (ACL) Reconstruction — Dott. Daniele Priano, Pediatric Orthopaedics · Information document: it does not replace an in-person assessment.
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Email: daniele.priano@ortopediaevolutiva.com