Paediatric ACL reconstruction (all-epiphyseal / all-inside)
Protocol for the patient with open growth plates operated with physeal-sparing techniques: more cautious progressions, growth surveillance and later return to sport.
Return to sport: typically 10-12 months, with growth surveillance at 6-12-24 months
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.
Children and adolescents often have not completed skeletal growth: their bones are still partly made of growth cartilage (physis), which can be damaged by the surgical procedures required for ACL reconstruction.
The all-epiphyseal technique creates the housing for the new ligament with tunnels entirely contained within the epiphyses, without crossing the physes; the all-inside technique uses fixation that crosses the physes to a limited extent. Both require significantly longer rehabilitation and carry a higher re-injury risk.
The risk of a second injury (graft or contralateral) in skeletally immature patients is reported up to 30-40% at two years when return to sport is early and not criteria-based: paediatric protocols are therefore more cautious than adult ones and always include a structured prevention programme.
Key parameters
- Weight bearing
- Often more cautious than in adults: partial weight bearing with crutches for the first 2-4 weeks depending on fixation.
- Brace
- Frequently prescribed, with ROM limited to 0-90° in the early weeks.
- ROM
- Early full extension; progressive flexion without forcing, to protect epiphyseal fixation.
- Stresses to avoid
- Varus/valgus and rotational forces on the knee in the first 3 months.
- Running
- Usually from month 4, only when strength and control criteria are met.
- Growth surveillance
- Clinical (and radiographic where indicated) review at 6, 12 and 24 months for limb length discrepancy or angular deviation.
Milestones at a glance
- Day 1Full extension, active quadriceps
- 2-4 weeks90° flexion, load progression as directed
- 6-8 weeksFull ROM, normal gait
- 4 monthsStraight-line running with strength criteria met
- 9-12 monthsReturn to sport after test battery
- 12-24 monthsGrowth follow-up (alignment and limb length)
Phases of the pathway
Phase 1 — Protection and activation
Weeks 0-6
Goals
- •Full extension and swelling control
- •Quadriceps activation without extension lag
- •Correct gait with prescribed aids
What to do
- •Quadriceps isometrics, straight leg raise, patellar mobilisations
- •Progressive active-assisted flexion within the brace-allowed range
- •Cryotherapy, compression, elevation; education of child and parents
- •Hip, core and ankle work in offloaded positions
Restrictions and precautions
- •No twisting or varus/valgus stress on the knee
- •Weight bearing per surgical prescription: do not anticipate
- •No return to school physical education
Criteria to progress
- ☐Passive extension 0° and flexion ≥90°
- ☐Decreasing effusion
- ☐Effective quad set without lag and non-antalgic gait within allowed loading
Note for the physiotherapist
In children, compliance is the critical factor: short and frequent doses, playful goals, parental involvement in the home programme. Check brace and crutch adherence at every session.
Phase 2 — ROM and strength recovery
Weeks 6-12
Goals
- •Full symmetrical ROM
- •Progressively symmetrical quadriceps and hamstring strength
- •Stable single-leg control
What to do
- •Progressive closed kinetic chain (mini squat, protected-range leg press, step up)
- •Gluteal and core strengthening, proprioception on stable then unstable surfaces
- •Cycling, walking in water, swimming (except breaststroke) once the wound has healed
Restrictions and precautions
- •No jumping, no change of direction
- •Avoid heavy open kinetic chain loading in the 0-30° arc
Criteria to progress
- ☐Full symmetrical ROM, dry knee
- ☐Single leg squat without dynamic valgus
- ☐Quadriceps strength ≥70-80% of the contralateral side
Phase 3 — Running and controlled plyometrics
Months 4-8
Goals
- •Resume running and aerobic conditioning
- •Jump and landing quality
- •Strength symmetry
What to do
- •Running progression: straight line → wide curves → figure-of-8 → acceleration/deceleration
- •Progressive bilateral then single-leg plyometrics with landing technique feedback
- •Movement screening (LESS score, drop vertical jump) and correction of dynamic valgus
Restrictions and precautions
- •No contact, no competitive gestures
- •Graded jump volume: avoid weekly load spikes
Criteria to progress
- ☐Hop tests with LSI ≥85-90%
- ☐Controlled landing without valgus on drop vertical jump
- ☐No pain or effusion after sessions
Note for the physiotherapist
Under 12-14 years the test-retest reliability of functional tests is lower: use several converging measures (strength, hop, movement quality, symptoms) rather than a single cut-off.
Phase 4 — Sport-specific work and graded return
Months 8-12
Goals
- •Safe sport-specific skills
- •Progressive reintegration into team training
- •Confidence of athlete and family
What to do
- •Individual sessions, then partial and finally full team training
- •Prevention programme (FIFA 11+ Kids) built into the warm-up
- •Assessment of skeletal maturity before clearance for high-risk sport
Restrictions and precautions
- •No competitive match play before full clearance
Criteria to progress
- ☐LSI ≥90% on hop tests and isokinetic strength
- ☐High IKDC and adolescent ACL-RSI scores
- ☐Full team training without symptoms
- ☐No clinical signs of growth disturbance
Return to sport / full activity
Typically 10-12 months; in the most immature patients and in pivoting sports clearance may be delayed further.
- ☐Hop tests (single, triple, crossover, 6 m timed) with LSI ≥90%
- ☐Isokinetic quadriceps and hamstring strength with LSI ≥90%
- ☐Movement quality: LESS score and drop vertical jump without dynamic valgus
- ☐High IKDC and high adolescent ACL-RSI
- ☐Skeletal maturity assessment (Tanner stage / bone age) and no limb length discrepancy or angular deviation
- ☐Prevention programme active and learned by the training group
Clearance is shared between surgeon, physiotherapist, family and coach. Clinical follow-up continues until the end of growth to detect physeal disturbances early.
Red flags: stop and contact us
- •New angular deviation (knock knee or bow leg) or limb length difference
- •Persistent bone pain at the epiphysis or metaphysis
- •Recurrent effusion after sessions or after returning to the field
- •Loss of full extension or joint locking
- •Giving way or a new twisting injury: stop and contact us
- •Fever, redness or discharge from the surgical wound
Guidelines and literature
- van Melick N et al. International Delphi consensus on ACL rehabilitation and return to sport in 10-18 year olds, 2023.
- Bixby EC, Heyworth BE. Management of ACL tears in skeletally immature patients. Curr Rev Musculoskelet Med 2024.
- PLUTO study — Pediatric ACL: Understanding Treatment Options (multicentre prospective cohort).
- Kay J et al. Earlier return to sport is associated with higher rates of graft failure in paediatric ACL reconstruction: systematic review, 2018.
- Dekker TJ et al. Return to sport and second injury in skeletally immature ACL reconstruction, 2020.
Key exercises, step by step
Each exercise belongs to a specific phase: do not anticipate them. Dosage is indicative and must be adapted by your physiotherapist.
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 raise
From 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
3. 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
4. Glute bridge
From 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
5. Single-leg balance
From 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
6. Controlled step-down
Strength 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. Progressive plyometrics
Impact 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
8. Agility and change of direction
Pre-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
Frequent questions
Can the all-epiphyseal technique damage growth?
It is designed precisely to avoid that: the tunnels remain within the epiphysis without crossing the growth plate. The risk is not zero, which is why clinical and radiographic follow-up continues until skeletal maturity to check alignment and limb length.
Can a young athlete return earlier than an adult?
No, quite the opposite: young athletes have the highest re-injury rates, especially in the first year. Respecting criteria and the 9-12 month window matters even more in adolescents than in adults.
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.
Paediatric ACL reconstruction (all-epiphyseal / all-inside) — Dott. Daniele Priano, Pediatric Orthopaedics · ortopediaevolutiva.com/en/rehabilitation/pediatric-acl-all-epiphyseal · Information document: it does not replace an in-person assessment.
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Email: daniele.priano@ortopediaevolutiva.com