We all assume that lower limb length discrepancy (LLD) matters for the body’s alignment and usually leads to compensations.
But it turns out—those compensations aren’t always what we think.
A recent study by Böhm H & Ugandhar Dussa C (2025) presents surprising findings.
Published in Gait & Posture (2025), this research explores how even mild leg length discrepancies can alter pelvic alignment and trigger compensatory gait patterns in children.
Until now, it was commonly believed that compensation for a longer leg involved lowering height through flexion adaptations, while the shorter leg typically compensated with toe-walking or a tiptoe posture to increase relative height on that side.
This study, however, shows that’s not the case.
🔍 What does the study say?
The study evaluated 51 children and adolescents with LLD of up to 3 cm. Even though all participants were clinically functional and free from joint contractures, the researchers identified significant compensatory patterns—especially when the discrepancy exceeded 2 cm.
🦵 How does the body compensate?
When one leg is longer, the body tends to:
- Increase ankle dorsiflexion on the longer side
- Flex the knee and hip more on that same side
- Tilt the pelvis down toward the shorter side
These adaptations aim to functionally shorten the longer leg and level the pelvis. But it doesn’t always work: the study found persistent lateral pelvic tilt, particularly in children with discrepancies over 2 cm.
In other words, the body couldn’t fully compensate for the difference.
And what about the shorter leg? What compensation was observed?
Surprisingly, there was no tiptoe posture on the shorter side. Interesting, right?
⚠️ Why does this matter?
First, even though these adaptations may be effective in the short term, they can lead to long-term consequences:
- Lumbar overload due to pelvic tilt.
- Pain in the knee, hip, or heel.
- Development of functional scoliosis.
- Higher risk of overuse injuries.
It’s also important to note: the long-held hypothesis that toe-walking on one side is a typical compensation for LLD can now almost be ruled out.
A clinically valuable insight: ankle dorsiflexion on the longer side was the most reliable marker of compensation—and may be key in deciding when to intervene.
👣 What can pediatric physiotherapy do?
- Assess true leg length always when facing pelvic asymmetry or altered gait.
- Consider gait analysis for discrepancies over 1 cm—even in the absence of pain.
- Utilize heel lifts or orthotics as a conservative management strategy—but measure carefully.
- Treat associated contractures that may worsen the imbalance (especially in the ankle).
- Monitor for signs of lumbar overload or ineffective compensation.
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