Paediatric & Adolescent
Children's Knee Injuries
Children and adolescents are not simply small adults. Their knees contain open growth plates (physes), immature cartilage and ligaments that attach close to these growth centres. This changes how injuries occur, how they present and — crucially — how they must be treated. Getting management right during growth protects the joint for a lifetime.
Why children's knees are different
- Open growth plates at the lower thigh bone (femur) and upper shin bone (tibia) — injury or surgery across a physis risks growth arrest, limb length discrepancy or angular deformity.
- Ligaments are often stronger than the growing bone, so what would be a ligament tear in an adult is often an avulsion (a bony pull-off) in a child.
- Cartilage and bone are more elastic — bones bend and buckle rather than snap.
- Traction apophyses (e.g. tibial tubercle, inferior patella pole) are vulnerable during growth spurts and repetitive sport.
- Rehabilitation must account for skeletal maturity, body mass changes and the psychological demands of young athletes.
Common paediatric knee conditions
Osgood-Schlatter disease
A traction apophysitis of the tibial tubercle where the patellar tendon attaches to the growing shin. Typically affects active children aged 10–15, especially in running and jumping sports. Presents as a painful, tender bump below the kneecap, worse with activity and kneeling. Almost always self-limiting once growth completes, but can persist as a prominent bony lump. Treatment is activity modification, ice, stretching (quadriceps and hamstrings), eccentric strengthening and short periods of rest during flare-ups. Surgery is very rarely indicated and reserved for a persistent painful ossicle in a skeletally mature patient.
Sinding-Larsen-Johansson syndrome
The equivalent apophysitis at the lower pole of the kneecap where the patellar tendon originates. Same age group and activities as Osgood-Schlatter. Managed with load reduction, physiotherapy and time.
Juvenile osteochondritis dissecans (OCD)
A subchondral bone lesion, most often on the medial femoral condyle. Presents with vague activity-related pain, effusions and sometimes locking if a fragment becomes unstable. Stable lesions in a skeletally immature child often heal with a period of protected weight bearing and activity restriction. Unstable or detached lesions require surgical fixation or cartilage restoration — with better healing potential than the adult form.
Patellar dislocation in children
Common in adolescents, especially girls, and often associated with trochlear dysplasia, patella alta and ligamentous laxity. First dislocations are usually managed non-operatively with bracing and structured physiotherapy. Recurrent instability may require MPFL reconstruction using techniques that respect the distal femoral physis.
Meniscal tears & discoid meniscus
Children have excellent healing potential, so meniscal repair — rather than removal — is strongly preferred. A discoid lateral meniscus is a congenital variant that can present with snapping, pain or a locked knee and may need arthroscopic saucerisation and stabilisation.
Tibial spine (eminence) avulsion
The paediatric equivalent of an ACL rupture — the ACL pulls off a fragment of bone from the tibial spine rather than tearing in its midsubstance. Undisplaced fractures may be treated in a cast in extension; displaced fragments require arthroscopic fixation (suture or screw) to restore stability and prevent chronic ACL laxity.
Paediatric ACL injuries
ACL injuries in children and adolescents are increasing sharply alongside year-round youth sport. They present in the same way as in adults — a twisting injury, a pop, immediate swelling and subsequent giving-way — but the management is fundamentally different because the growth plates are still open.
Why non-operative treatment usually fails
Delaying reconstruction in an active child with a torn ACL leads to further giving-way episodes, secondary meniscal tears and cartilage damage — accelerating the timeline to early arthritis. Modern practice in an active child is therefore early reconstruction, using a technique matched to skeletal maturity.
Skeletally immature (pre-pubertal)
Physeal-sparing techniques such as an all-epiphyseal or iliotibial band (Micheli-Kocher) reconstruction avoid crossing the growth plates entirely.
Adolescent (peri-pubertal)
Partial transphyseal reconstruction using soft-tissue grafts (hamstring or quadriceps tendon) with vertical tunnels and no hardware across the physis to minimise growth disturbance.
Skeletally mature adolescent
Standard adult transphyseal reconstruction can be performed safely once the growth plates are closing or closed.
Key differences from adult ACL reconstruction
- Graft choice: soft-tissue grafts (hamstring, quadriceps tendon) are preferred in children — bone-patellar tendon-bone grafts risk damaging the tibial tubercle apophysis.
- Tunnel placement: vertical, central tunnels of the smallest safe diameter that spare the physes; hardware kept away from growth plates.
- Growth monitoring: assessment of skeletal age (bone age X-ray, Tanner staging, standing leg alignment views) before and after surgery to detect any limb length or angular changes.
- Meniscal preservation: a much lower threshold to repair rather than trim meniscal tears — children heal exceptionally well.
- Rehabilitation: slower, more supervised return to sport — young athletes have higher re-injury rates and often need longer psychological readiness.
- Return to pivoting sport: typically 9–12 months, guided by objective strength, hop testing and neuromuscular control — not by calendar time alone.
- Bracing: in the young paediatric patient and after meniscal repair a functional brace is typically used for around 6 weeks.
Risks specific to the growing knee
- Growth arrest with resulting limb length discrepancy
- Angular deformity (valgus or varus) from asymmetric physeal injury
- Higher re-rupture and contralateral ACL injury rates than in adults
- Standard ACL surgical risks — infection, stiffness, graft failure, DVT
Paediatric ACL rehabilitation
Week 0–2
Protect & settle
Brace, partial weight bearing on crutches (adjusted if a meniscal repair has been performed), swelling control, early quadriceps activation and full passive extension.
Week 2–6
Motion & control
Progressive range of motion, closed-chain strengthening, gait re-education, stationary bike. Wean the brace as guided.
Month 3–6
Strength & running
Gym-based strengthening, single leg control, running progression once quadriceps strength and hop symmetry targets are met.
Month 6–12
Return to sport
Sport-specific agility, plyometrics and neuromuscular training. Return to pivoting sport only after passing objective return-to-sport testing — typically 9–12 months.
Variations in the rehabilitation protocol can occur based on Mr Rehmatullah's assessment, the technique used and any associated meniscal or cartilage surgery.
When to seek review
A child with a swollen knee after a twisting injury, recurrent giving-way, a locked knee, or persistent activity-related knee pain that limits sport should be reviewed. Early accurate diagnosis — often with MRI — protects the joint and allows a treatment plan tailored to the child's skeletal maturity and sporting goals.