Reviewed by Dr Vishal Pai
A paediatric ACL reconstruction replaces a torn anterior cruciate ligament (ACL) in a child or teenager whose bones are still growing, using a technique chosen to protect the growth plates. This page is written for parents and for young people. It covers when surgery is advised, how the growth plates are protected, recovery, results and risks.
At a Glance
- The ACL is one of the main ligaments that keeps the knee stable when you twist, pivot or land.
- Children have growth plates, areas of growing cartilage near the ends of the bones, so the operation is planned around how much growth is left.
- Younger children have a technique that avoids the growth plates. Older teenagers who are close to the end of growth usually have a technique closer to the adult operation.
- Rehabilitation takes many months, and return to sport depends on passing strength and movement tests, not on time alone.
- Young people have a higher risk of tearing the ACL again than adults, so a structured rehabilitation program matters.
What is a paediatric ACL reconstruction?
An ACL reconstruction replaces a torn ACL with a graft to make an unstable knee more stable. ACL reconstruction in children differs significantly from adult procedures. Children have open growth plates, which are areas of developing cartilage near the ends of long bones responsible for growth. Surgical techniques that cross or disrupt these plates risk bone deformity or leg length differences.
Therefore, the surgical approach must be selected based on your child’s age, sex and skeletal maturity (how close the bones are to finishing growing), rather than just height or chronological age. A thorough assessment, including X-rays to determine bone age, is essential before choosing the appropriate technique.
ACL reconstructions in young Australians are becoming more common, and the rate is rising fastest in children aged 5 to 14. [1] In Victoria, hospital admissions for ACL injuries in 5- to 14-year-olds more than doubled between 2005 and 2015. [2]
Who might need a paediatric ACL reconstruction?
An ACL tear in a child can be distressing for families. Parents often receive conflicting advice, such as avoiding surgery, concerns about growth plate damage, or recommendations to wait and see.
Previously, non-operative management was often recommended for children with ACL tears, with surgery delayed until growth plates closed. Some children can manage with physiotherapy and activity changes, especially if they avoid high-risk pivoting sports. However, studies of children treated without surgery report ongoing instability in many, and many do not get back to their previous level of sport. [3]
Delaying ACL reconstruction in children increases the risk of meniscal tears (damage to the cartilage cushions inside the knee), which cannot be fully restored once damaged. [3] [4] Waiting more than a year makes a meniscal tear that needs surgery several times more likely, and fewer of these tears can be repaired. [5] Losing part of a meniscus increases the risk of arthritis in the long term.
For most active children with a complete ACL tear, reconstruction gives a more stable knee and a better chance of returning to sport than treatment without surgery, when the appropriate technique is used. [3] Dr Vishal Pai usually advises earlier surgery for young people who have a repairable meniscal tear or who want to return to pivoting sport.
What is involved in a paediatric ACL reconstruction?
The choice of surgical technique depends primarily on your child’s remaining growth. Dr Vishal Pai carefully assesses skeletal maturity before recommending an approach.
Physeal-sparing (growth plate–sparing) reconstruction avoids the growth plates. It is preferred for younger children with significant growth remaining, typically under 12 years old or in early puberty. There are two techniques:
- All-epiphyseal reconstruction places the graft entirely within the epiphysis (the end of the bone beyond the growth plate), so the tunnels do not cross the growth plates. It is technically demanding.
- Extraphyseal reconstruction uses a strip of the iliotibial band (a band of tissue on the outside of the thigh), passed around the bone instead of through it, so no tunnels are drilled through the growth plates.
Transphyseal reconstruction (across the growth plate) uses tunnels that pass through the growth plates, similar to adult procedures. This approach is suitable for older adolescents nearing skeletal maturity. When performed with soft-tissue grafts and precise tunnel placement, the risk of significant growth disturbance is low. [6] No technique removes the risk of growth problems completely. [7]
In children, soft-tissue grafts, most commonly the hamstring tendons, are preferred over grafts that contain bone, such as the patellar tendon, so that no bone plug sits across the growth plate. In some cases, the quadriceps tendon may be considered as an alternative, particularly for revision procedures or when the hamstring tendons are unavailable.
Children and adolescents are at higher risk of ACL graft re-rupture than adults. For this reason, Dr Vishal Pai routinely considers adding a lateral extra-articular procedure (LEAP) at the time of reconstruction. This procedure reinforces the rotational stability of the knee and can reduce re-rupture rates. [8] Read more about a LEAP and its benefits in ACL reconstruction.
The steps involved in a paediatric ACL reconstruction include:
1. Knee arthroscopy
The knee is examined thoroughly to confirm the ACL tear and identify any secondary injuries. Meniscal tears and cartilage damage are addressed at the same time.
2. Graft harvest
The hamstring tendons are harvested through a small incision on the inside of the knee.
3. Tunnel placement
Bone tunnels are carefully positioned to avoid or minimise disruption to the growth plates, guided by X-ray screening in theatre.
4. Graft passage and fixation
The graft is passed through the tunnels and secured with fixation devices appropriate for a growing skeleton.
5. Lateral extra-articular procedure
A strip of tissue from the outside of the knee is re-routed to provide additional rotational control.
How long does it take to recover from a paediatric ACL reconstruction?
Recovery from a paediatric ACL reconstruction follows a similar timeline to adults, but the rehabilitation program is tailored for a growing child. Return to sport is determined by meeting objective strength and movement milestones, not by time alone. Dr Vishal Pai works with your child’s physiotherapist to check readiness before competition. As a rough guide:
- Same day or next dayYour child will usually go home on the day of surgery or after one night in hospital.
- First weekPhysiotherapy begins. Getting the knee fully straight is the most important early goal.
- 1–2 weeksMost children are back at school. A note for reduced physical education can be provided.
- 2 weeksThe wound is checked and the stitches are removed at the first follow-up appointment.
- 2–3 weeksMost young people are able to stop using crutches.
- 8 weeksBy this stage, Dr Vishal Pai expects the knee to straighten fully and to bend beyond 90 degrees.
- 4 monthsDr Vishal Pai checks the stability of the graft. Some swelling may still be present.
- 12 months or laterYour child can return to competitive sport once they have passed return-to-sport testing.
Returning too early increases the risk of re-injury, so these criteria are strictly followed. In young people, going back to sport too early is the main factor linked to a second ACL injury. [9]
What results can you expect?
Most children and teenagers return to sport after an ACL reconstruction, and most get back to their previous level. [10]
Growth problems after surgery, such as a difference in leg length or a leg that grows at an angle, are uncommon. They affect about 2 to 3 in 100 children, and only a small number need an operation to correct them. [6] [11]
The main setback is another ACL injury, and young people have a higher risk than adults. In people under 20, about 1 in 5 tear the graft and a similar number injure the ACL in the other knee, mostly within 2 years of surgery. [12] Adding a LEAP may lower the chance of the graft tearing in children. [8]
What are the risks and complications?
Every operation carries risks, and Dr Vishal Pai goes through them with you and your child before you decide. The main risks of a paediatric ACL reconstruction are:
- Tearing the graft again, or injuring the ACL in the other knee (see above)
- Disturbance to the growth plate, causing a difference in leg length or an angled leg, which is uncommon and occasionally needs further surgery [6] [11]
- Infection, in about 3 in 1,000 young people, which may need a further operation to wash out the knee [11]
- Stiffness or difficulty getting the knee fully straight, which occasionally needs a further procedure
- A numb patch on the inside of the leg after a hamstring graft, which usually improves with time
- Pain or weakness where the graft was taken, which usually settles
Rarely, there is bleeding into the knee, a blood clot in the leg, or injury to the nerve or blood vessels behind the knee. Some young people don’t return to their previous level of sport, and the risk of arthritis later in life is higher than for people who have never injured their knee. You will receive a written information sheet with the full list of risks.
Where does Dr Vishal Pai consult and operate?
Dr Vishal Pai consults at Sandringham Orthopaedic Specialists, Suite 1, 60 Bay Road, Sandringham. He performs ACL reconstructions at Calvary Holmesglen Private Hospital, 490 South Road, Moorabbin, and The Avenue Hospital, 40 The Avenue, Windsor. Patients come from across Bayside, Glen Eira and the Mornington Peninsula, and some travel from regional Victoria.
References
Show all 12 referencesHide references
- Zbrojkiewicz D et al. 2018. Increasing rates of anterior cruciate ligament reconstruction in young Australians, 2000–2015. Medical Journal of Australia.
- Shaw L et al. 2017. Trends in pediatric and adolescent anterior cruciate ligament injuries in Victoria, Australia 2005–2015. International Journal of Environmental Research and Public Health.
- James EW et al. 2021. Early operative versus delayed operative versus nonoperative treatment of pediatric and adolescent anterior cruciate ligament injuries: a systematic review and meta-analysis. The American Journal of Sports Medicine.
- Kay J et al. 2018. Earlier anterior cruciate ligament reconstruction is associated with a decreased risk of medial meniscal and articular cartilage damage in children and adolescents: a systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy.
- Hickie KL et al. 2025. The association between delaying anterior cruciate ligament reconstruction in adolescents and increasing meniscal and chondral pathology: a cohort study of 2740 adolescents. The American Journal of Sports Medicine.
- Longo UG et al. 2017. Anterior cruciate ligament reconstruction in skeletally immature patients: a systematic review. The Bone & Joint Journal.
- Tahir M et al. 2025. Physeal-sparing ACL reconstruction has equivalent survivorship and functional outcomes as transphyseal reconstruction but does not prevent growth disturbance: a systematic review of clinical and radiological outcomes. The Knee.
- Kotipalli S et al. 2026. Lateral extra-articular tenodesis with anterior cruciate ligament reconstruction in pediatric and skeletally immature patients: a systematic review and meta-analysis. The American Journal of Sports Medicine.
- Dekker TJ et al. 2017. Return to sport after pediatric anterior cruciate ligament reconstruction and its effect on subsequent anterior cruciate ligament injury. The Journal of Bone and Joint Surgery (American Volume).
- Kay J et al. 2018. Over 90% of children and adolescents return to sport after anterior cruciate ligament reconstruction: a systematic review and meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy.
- Nogaro MC et al. 2020. Paediatric and adolescent anterior cruciate ligament reconstruction surgery. The Bone & Joint Journal.
- Webster KE et al. 2016. Exploring the high reinjury rate in younger patients undergoing anterior cruciate ligament reconstruction. The American Journal of Sports Medicine.
Frequently asked questions
What training does Dr Vishal Pai have in children’s ACL surgery?
In 2015, Dr Vishal Pai completed a six-month international fellowship in paediatric orthopaedics at Shriners Hospitals for Children in Portland, USA, which included managing ACL injuries in young patients.
ACL reconstruction in children requires a different surgical approach, different technique selection and a different mindset from adult surgery.
My child still has years of growth left. Is it safe to operate now?
Surgery can usually go ahead, provided the technique is matched to your child’s skeletal maturity. Modern physeal-sparing and physeal-respecting techniques are specifically designed for children with significant growth remaining. Growth problems after surgery are uncommon, but they can happen with any technique. [6] [7]
What happens if we choose not to operate?
Some children can manage with physiotherapy and activity modification, especially if they avoid high-risk pivoting sports. However, the knee remains unstable, and episodes of giving way increase the risk of further meniscal and cartilage damage. Over time, this can lead to early-onset arthritis.
How long will my child be off school?
Most children return to school within 1 to 2 weeks after surgery, depending on mobility needs. A note for reduced physical education can be provided.
Will my child need physiotherapy?
Yes. Physiotherapy is essential for recovery and should begin within the first week after surgery. The quality and consistency of rehabilitation significantly influence the final outcome. Dr Vishal Pai will refer your child to a physiotherapist who regularly treats ACL injuries.
What is the risk of re-injury?
Children and adolescents have a higher risk of re-rupture than adults, especially in the first 2 years after surgery. [12] This risk may be lowered by adding a LEAP, following a structured return-to-sport program, and completing formal functional testing before competition.
Next step
Talk through your options
If your child has injured their ACL, Dr Vishal Pai can examine their knee, review their scans and explain all the options, including treatment without surgery.