Pediatric ACL Injuries: Prevention, Diagnosis, Treatment & Rehab

Over recent years, anterior cruciate ligament (ACL) injuries have risen in children²³. This worries clinicians who must navigate uncertain evidence while supporting the child and family. Key questions often arise:

• Do children with ACL injury mature “normally” compared with uninjured peers?⁴

• Should sport participation continue, or should school and other interests be prioritized?⁴

• Is an ACL rupture a life-altering event?⁴

ACL injury in childhood may carry lifelong consequences, including increased risk of further injuries, meniscal damage, and early osteoarthritis⁵ — yet the evidence base remains limited for many decisions⁶.

Children are a vulnerable population. Clinicians have a duty to give clear information, support shared decision-making (child + guardians), and tailor effective management. Long-term outcomes (including OA risk) are still insufficiently studied⁴, which makes ethically sound, family-centred decision-making even more important⁴.

Prevention of Pediatric ACL Injury

An ACL tear in childhood can have long-term impact⁴, including a higher bilateral injury risk⁷. Prevention matters for both first injuries and re-injury after return to sport⁴.

Well-designed neuromuscular warm-up programs (e.g., in football/soccer) reduce ACL injuries in youth⁸–¹⁰. Programs should target modifiable biomechanics⁴ and coach athletes to avoid high-risk knee positions during cutting and landing.

Core components to include

• Strength training (hip/knee, trunk)

• Plyometrics with landing mechanics

• Agility and change-of-direction drills¹¹

• Coaching education on wide foot base when cutting and knee flexion when landing

Practical advantages

• Easy to implement⁴

• Minimal or no equipment needed⁴

• Fits into team training or PE 2–3×/week⁴

FIFA programs (11+, 11+ Kids) reduce lower-limb injuries by >50% in football¹²–¹⁴ and improve motor control, balance, agility¹⁴. Consistency and compliance drive outcomes¹⁶ ¹⁷; clinicians should advocate prevention across schools, clubs and clinics⁴.

Diagnosis of Pediatric ACL Injury

Early, accurate diagnosis sets the course for appropriate treatment⁴. Combine history, exam, special tests and imaging to form a coherent clinical picture⁴.

Clinical red flags & nuances

• Hemarthrosis within 24 h of trauma strongly suggests structural injury⁴.

• Children are harder to assess: communication is variable; physiologic laxity is greater (test both knees); MRI is complicated by developmental variants¹⁸.

• Skeletal immaturity adds risk of patellar sleeve fractures and physeal injuries⁴.

Imaging

• X-ray to exclude fracture (e.g., patellar sleeve, physeal injury).

• MRI to confirm ACL rupture and assess meniscus/chondral lesions¹⁹.

• Locked knee → MRI to rule out bucket-handle meniscal tear or cartilage injury.

Special tests (no single test or image is diagnostic on its own)⁴

• Lachman test

• Anterior drawer

• Pivot shift (and lateral pivot shift)

• Slocum test

Management: Shared Decisions With Child & Guardians

Treatment goals

• Restore knee stability and function for an active life

• Reduce risk of meniscal/chondral injury, osteoarthritis, and later surgery

• Minimize risk of growth disturbance or deformity in femur/tibia

Options to discuss

• High-quality rehabilitation alone (conservative)

• ACL reconstruction plus rehabilitation

Rehabilitation is essential in both pathways and must be adapted to the child’s physiological and psychological development. Children are not small adults⁴ — supervision by pediatric-savvy physiotherapists and active parental involvement are critical.

Rehabilitation Focus (Pediatric-specific)

• Dynamic, multi-joint neuromuscular control

• Individualized loading relative to age and maturation

• Biomechanically sound movement patterns (cutting, landing)

• Stepwise progression through Phases II–III of a pediatric ACL protocol

• Address re-injury anxiety and rebuild knee confidence

• Close coordination with the sports team

• Daily parental support for adherence

Milestone-based phase targets

• Pre-hab (pre-op): full extension, ≥120° flexion, no effusion, good quad control

• Phase I–II: maintain full extension, ≥120° flexion, restore quad control

• Phase II–III: full ROM, ≥80% strength & hop symmetry, running without swelling

• Phase III–IV: sport-specific training, >90% strength & hop symmetry, pain-free activity, psychological readiness

Strength testing: Prefer isokinetic dynamometry or validated handheld dynamometry. If using handheld, increase symmetry threshold by +10% (e.g., 90% → 100%) due to measurement bias⁴.

Exercise Examples by Phase

Phase I

• Stationary cycling (gentle ROM, circulation)

• Active knee extension (painless, full extension focus)

• Bodyweight squats (quad + hip control)

• Single-leg balance (proprioception)

Also: quad sets; closed-chain hip/pelvic control drills

Phase II

• Single-leg squat

• Forward/side step-ups

• Lunges on BOSU (dynamic stability)

• BOSU squats (control through range)

• Bridge variations (hip & trunk stability)

Phase III

• Split squats with dumbbells

• Leg press progression

• Hopping/landing drills

• Agility and change-of-direction

• Stairs/hurdle patterns

Phase IV

• Integrate a prevention program (e.g., FIFA 11+ / 11+ Kids) to lower re-injury risk

Return to Sport (RTS): Time & Criteria

RTS must be criteria-based, not calendar-based. Typical timelines:

Pathway	Minimum timeframe	Notes
Conservative care	3–6 months²²	Progress only if criteria met
Post-reconstruction	≥9 months²³	Young athletes have high re-injury risk in year 1²³

Additional guidance:

• Consider delaying pivoting sports to ≥12 months post-op⁴.

• Train the uninjured limb during rehab (contralateral risk)²⁴.

• Maintain prevention programs after RTS.

Special Pediatric Considerations⁴

• Avoid boredom → use game-based, varied sessions.

• Be cautious interpreting tests: single-leg hop and isokinetics have higher measurement error in younger kids²⁵.

• Prioritize movement quality over numeric symmetry in young children.

• If you lack experience with movement-quality testing, refer to a specialist.

• Adult RTS criteria may not fit pre-pubertal athletes — use clinical judgment.

Outcome Measures (Child-friendly)

• Child Health Questionnaire

• PedsQL

• Pediatric PROMIS

• Pedi-IKDC

• KOOS-Child

• Pediatric Functional Activity Brief Scale

Ethics: Acting in the Child’s Best Interest

What is the clinician’s duty of care?⁴ Decisions are complex and evidence is limited. There is no universal ethical rulebook, but every child has a right to injury prevention and safe sport⁴.

• Practice shared decision-making (clinician + child + guardians).

• Communicate risks/benefits in age-appropriate language; obtain assent.

• Prioritize the integrity of the knee and long-term health.

• Base recommendations on best available evidence and clear, realistic expectations.

References

1. British Journal of Sports Medicine (BJSM). Paediatric anterior cruciate ligament (ACL) injuries. https://www.youtube.com/watch?v=MM6UY1MpqAE. Published on 13 April 2019.

2. Werner BC, Yang S, Looney AM, Gwathmey FW Jr. Trends in Pediatric and Adolescent Anterior Cruciate Ligament Injury and Reconstruction. J Pediatr Orthop. 2016;36(5):447-52.

3. Shaw L, Finch CF. Trends in Pediatric and Adolescent Anterior Cruciate Ligament Injuries in Victoria, Australia 2005-2015. Int J Environ Res Public Health. 2017 Jun 5;14(6). pii: E599.

4. Ardern CL, Ekås G, Grindem H, Moksnes H, Anderson AF, Chotel F, Cohen M, Forssblad M, Ganley TJ, Feller JA, Karlsson J, Kocher MS, LaPrade RF, McNamee M, Mandelbaum B, Micheli L, Mohtadi NGH, Reider B, Roe JP, Seil R, Siebold R, Silvers-Granelli HJ, Soligard T, Witvrouw E, Engebretsen L. 2018 International Olympic Committee Consensus Statement on Prevention, Diagnosis, and Management of Pediatric Anterior Cruciate Ligament Injuries. Orthop J Sports Med. 2018 Mar 21;6(3):2325967118759953

5. Whittaker JL, Woodhouse LJ, Nettel-Aguirre A, Emery CA. Outcomes associated with early post-traumatic osteoarthritis and other negative health consequences 3-10 years following knee joint injury in youth sport. Osteoarthritis Cartilage. 2015 Jul;23(7):1122-9.

6. Moksnes H, Engebretsen L, Risberg MA. The current evidence for treatment of ACL injuries in children is low: a systematic review. J Bone Joint Surg Am. 2012 Jun 20;94(12):1112-9.

7. Paterno MV, Rauh MJ, Schmitt LC, Ford KR, Hewett TE. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. Am J Sports Med. 2014 Jul;42(7):1567-73.

8. Waldén M, Atroshi I, Magnusson H, Wagner P, Hägglund M. Prevention of acute knee injuries in adolescent female football players: cluster randomised controlled trial. BMJ. 2012 May 3;344:e3042.

9. Soligard T, Myklebust G, Steffen K, Holme I, Silvers H, Bizzini M, Junge A, Dvorak J, Bahr R, Andersen TE. Comprehensive warm-up programme to prevent injuries in young female footballers: cluster randomised controlled trial. BMJ. 2008 Dec 9;337:a2469.

10. Silvers-Granelli H, Mandelbaum B, Adeniji O, Insler S, Bizzini M, Pohlig R, Junge A, Snyder-Mackler L, Dvorak J. Efficacy of the FIFA 11+ Injury Prevention Program in the Collegiate Male Soccer Player. Am J Sports Med. 2015 Nov;43(11):2628-37.

11. Emery CA, Roy TO, Whittaker JL, Nettel-Aguirre A, van Mechelen W. Neuromuscular training injury prevention strategies in youth sport: a systematic review and meta-analysis. Br J Sports Med. 2015 Jul;49(13):865-70.

12. Thorborg K, Krommes KK, Esteve E, Clausen MB, Bartels EM, Rathleff MS. Effect of specific exercise-based football injury prevention programmes on the overall injury rate in football: a systematic review and meta-analysis of the FIFA 11 and 11+ programmes. Br J Sports Med. 2017 Apr;51(7):562-571.

13. Rössler R, Junge A, Bizzini M, Verhagen E, Chomiak J, Aus der Fünten K, Meyer T, Dvorak J, Lichtenstein E, Beaudouin F, Faude O. A Multinational Cluster Randomised Controlled Trial to Assess the Efficacy of '11+ Kids': A Warm-Up Programme to Prevent Injuries in Children's Football. Sports Med. 2018 Jun;48(6):1493-1504.

14. Rössler R, Donath L, Bizzini M, Faude O. A new injury prevention programme for children's football--FIFA 11+ Kids--can improve motor performance: a cluster-randomised controlled trial. J Sports Sci. 2016;34(6):549-56.

15. Attwood MJ, Roberts SP, Trewartha G, England ME3, Stokes KA. Efficacy of a movement control injury prevention programme in adult men's community rugby union: a cluster randomised controlled trial. Br J Sports Med. 2018 Mar;52(6):368-374.

16. Hägglund M1, Atroshi I, Wagner P, Waldén M. Superior compliance with a neuromuscular training programme is associated with fewer ACL injuries and fewer acute knee injuries in female adolescent football players: secondary analysis of an RCT. Br J Sports Med. 2013 Oct;47(15):974-9.

17. Soligard T1, Nilstad A, Steffen K, Myklebust G, Holme I, Dvorak J, Bahr R, Andersen TE. Compliance with a comprehensive warm-up programme to prevent injuries in youth football. Br J Sports Med. 2010 Sep;44(11):787-93.

18. Thapa MM1, Chaturvedi A, Iyer RS, Darling SE, Khanna PC, Ishak G, Chew FS. MRI of pediatric patients: Part 2, normal variants and abnormalities of the knee. AJR Am J Roentgenol. 2012 May;198(5):W456-65.

19. Kocher MS, DiCanzio J, Zurakowski D, Micheli LJ. Diagnostic performance of clinical examination and selective magnetic resonance imaging in the evaluation of intraarticular knee disorders in children and adolescents. (abstract only) Am J Sports Med. 2001 May-Jun;29(3):292-6.

20. Yellin JL, Fabricant PD, Gornitzky A, Greenberg EM, Conrad S, Dyke JA, Ganley TJ. Rehabilitation Following Anterior Cruciate Ligament Tears in Children: A Systematic Review. JBJS Rev. 2016 Jan 19;4(1). pii: 01874474-201601000-00004.

21. Ardern CL, Glasgow P, Schneiders A, Witvrouw E, Clarsen B, Cools A, Gojanovic B, Griffin S, Khan KM, Moksnes H, Mutch SA, Phillips N, Reurink G, Sadler R, Silbernagel KG, Thorborg K, Wangensteen A, Wilk KE, Bizzini M. 2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern. Br J Sports Med. 2016 Jul;50(14):853-64.

22. Grindem H, Eitzen I, Engebretsen L, Snyder-Mackler L, Risberg MA. Nonsurgical or Surgical Treatment of ACL Injuries: Knee Function, Sports Participation, and Knee Reinjury: The Delaware-Oslo ACL Cohort Study. J Bone Joint Surg Am. 2014 Aug 6;96(15):1233-1241.

23. Grindem H, Snyder-Mackler L, Moksnes H, Engebretsen L, Risberg MA. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016 Jul;50(13):804-8.

24. Dekker TJ, Godin JA, Dale KM, Garrett WE, Taylor DC, Riboh JC. Return to Sport After Pediatric Anterior Cruciate Ligament Reconstruction and Its Effect on Subsequent Anterior Cruciate Ligament Injury. J Bone Joint Surg Am. 2017 Jun 7;99(11):897-904

25. Johnsen MB, Eitzen I, Moksnes H, Risberg MA. Inter- and intrarater reliability of four single-legged hop tests and isokinetic muscle torque measurements in children. Knee Surg Sports Traumatol Arthrosc. 2015 Jul;23(7):1907-16.