Clubfoot and Ponseti: joint effects and the role of bracing

Quick summary

• Ankle (strong evidence, meta-analyses): after Ponseti, children push off more weakly, have a narrower ankle range of motion, and the foot tends to point inwards when walking.
• Knee and hip: the changes are mainly compensatory. The knee straightens slightly less, and the hip rotates outwards so that the foot does not point inwards.
• Casting and bracing: the recorded complications involve the skin and the back of the knee. No large study has shown that casts or braces damage the knee or hip joint.
• Achilles tendon: if the brace does not hold the foot lifted up (dorsiflexion), the Achilles tendon easily tightens again. This is the most common type of relapse; a second Achilles tenotomy is the most common additional operation.
• Late stage (relapse, late treatment): in gait-analysis studies, 50–70% of relapsed children rotate the hip outwards to compensate, 71% have internal tibial torsion and 29% have knee hyperextension; about 30% of relapsed children had needed a second tenotomy.
• A conventional ankle-foot orthosis (AFO) that only holds the foot straight is not enough: in one comparative study, 83% relapsed with an AFO versus 31% with a Denis Browne brace.

Clubfoot and the Ponseti method

• Manipulation and casting: each week the foot is gently corrected and cast from the toes to the groin with the knee bent at 90°. Usually 5–7 casts are needed.
• Percutaneous Achilles tenotomy: most children need a small cut in the Achilles tendon so the foot can be lifted up. A further cast for about 3 weeks lets the tendon heal at its new length.
• Foot abduction brace (Denis Browne): two shoes joined by a bar. The affected foot is turned out 60–70° and lifted 10–15°. It is worn almost all day for the first 3 months, then during sleep until age 4–5.

How to read the evidence: levels of confidence

After treatment: gait at the ankle, knee and hip

Ankle – strong evidence

• Meta-analysis of 20 studies (Grin et al., 2023): compared with healthy children, children after Ponseti have less plantarflexion at push-off, less dorsiflexion in swing and a significantly narrower ankle range of motion. The foot also points inwards more when walking.
• Meta-analysis of kinetics (Tuinsma et al., 2018): ankle push-off moment and power are lower than in healthy children. However, they are no worse than in children treated surgically.

Knee – moderate evidence

• In mid-stance, the knee of children after Ponseti extends less fully than in healthy children.
• When the foot points inwards, the ground reaction force shifts behind the knee. One study recorded about 7° more knee flexion and about 60% higher knee flexion moment in stance (in treated clubfoot in general, not Ponseti only).
• Children treated with French physiotherapy often walk with knee hyperextension (41% of feet), whereas children treated with Ponseti casting do not toe-walk.
• After the old extensive release surgery, the knee often shows valgus, mild hyperextension and quadriceps weakness. This is why Ponseti is preferred to surgery.

Hip – moderate evidence

• Follow-up to age 5 (Karol et al., 2009): 85% of Ponseti children had in-toeing of the leg and foot, and 71% of limbs had external hip rotation in stance to compensate.
• When ankle push-off is weak, the knee and hip must generate more power to compensate. The authors call this a compensatory mechanism.
• Clubfoot itself is associated with increased internal hip rotation, so not every hip change is caused by the treatment.

During casting

During Denis Browne bracing

• Bone torsion: a study of 20 children who wore the brace for an average of 33 months, measured by ultrasound. Femoral anteversion and external tibial torsion stayed within normal limits; the authors concluded the brace caused no pathological change (weak evidence because the group was small).
• Flattening of the healthy foot: in unilateral clubfoot the healthy foot also wears the brace and becomes clearly flatter during this period (moderate evidence).
• Skin: about 14% of children using the Mitchell–Ponseti brace had skin abrasions, mainly on the top of the foot.

The Achilles tendon, relapse and repeat tenotomy

Late stage: relapse, late treatment and repeated tenotomy

• The probability of relapse can reach 52% by age 6 and falls clearly with correct bracing; with correct bracing, only about 12% need surgery.
• In Ponseti’s own study: 7% relapsed among children who braced correctly versus 78% among those who did not.
• Children treated after walking age: a meta-analysis of 654 feet found a relapse rate of 18%.
• A multicentre study of 429 feet achieved correction in 87%, but 31% relapsed, mainly because of non-adherence to bracing. Among children aged 1–10, about 31% relapsed and needed re-casting, re-bracing or tendon transfer.

Effects on the ankle, knee and hip in relapse

The Achilles tendon and repeated tenotomy

• Among relapsed children, about 30% had already needed a second tenotomy. Both the clubfoot group and the relapse group had shorter calf muscles, longer Achilles tendons and poorer walking function than typically developing children; the authors believe tenotomy is not the only cause.
• The calf on the clubfoot side is smaller than the healthy side from the start. The first tenotomy does not worsen calf atrophy in the short term.
• The Achilles tendon can heal completely after tenotomy, even in older children (average age 5), and calf strength returns to normal.
• Children under 2 who relapse usually have another percutaneous tenotomy. Older children usually need an open Z-lengthening of the Achilles tendon. Recurrent equinus is the most common reason for re-operation after Ponseti.

The role of orthoses at the late stage

Which braces work?

• It actively pushes the foot into abduction (outward rotation) and dorsiflexion, not merely “holding” the position.
• It has a support above the knee, with the knee flexed, to correct tibial torsion. A brace that stops below the knee cannot do this.
• The child accepts wearing it for enough hours.

Braces with good evidence

• Custom-moulded dynamic knee-ankle-foot orthosis (dynamic KAFO): 20 children (30 feet) had no relapse during 4 years of bracing, with high adherence. Notably, in-toeing in these children was not compensated by external rotation at the knee or hip, unlike what is often seen after a bar brace.
• Dynamic torsional KAFO (DTKAFO): 88% of children adherent, only 8% relapse after 2 years, significant improvement in ankle range of motion, comparable to a bar brace.
• Custom unilateral lower-leg orthosis: switching from a bar brace to this orthosis at any time did not increase the rate of surgery.
• AFO by day plus a bar brace at night: better ankle range of motion, better function and fewer relapses than a bar brace alone.
• Plantar pressure-distributing orthoses: for relapsed children of walking age, the authors suggest this type may improve foot and ankle function (still a hypothesis).

Practical implications

• At the late stage, the brace must be designed and moulded for each child, based on the remaining deformity (equinus, adduction, varus, tibial torsion).
• The brace must hold the ankle in true dorsiflexion without the heel riding up, because this is the key to preventing recurrent equinus and avoiding another tenotomy.
• When there is tibial torsion or compensatory hip rotation, consider a brace with an above-knee part rather than a below-knee AFO only.

What there is no evidence for yet

• There is no systematic review, randomised trial or large follow-up study on knee or hip injury from casts or braces.
• No study has followed children into adulthood to see whether the knee or hip develops early arthritis.
• No study has directly measured the “actual dorsiflexion inside the brace” against the rate of repeat tenotomy; studies so far only measure whether parents have the child wear the brace long enough.
• No study has measured knee angle or knock-knee angle in children braced at 70° versus 60° of external rotation.

Practical advice for parents

While your child is in a cast

• Check the toes every day: pink, warm and moving. Toes that are blue, cold, very swollen or retracting into the cast → tell the doctor at once.
• Look at the back of the knee and the cast edges for red skin.
• A cast that is loose, slipping, cracked, soft, wet or smells bad → get it checked; do not wait for the next appointment.

While your child wears the brace

• Wear it almost all day (23 hours) for the first 3 months, then during night sleep and naps.
• Press the heel down onto the sole before fastening; fasten the middle strap (across the ankle) first.
• After taking the brace off, check that the heel has left a mark on the sole. A heel that does not touch the sole, or a foot that keeps slipping out, is an early sign of relapse.
• The bar should be as wide as the child’s shoulders; change the size as the child grows.
• Red marks that have not faded about 1 hour after removing the brace → tell the orthotic clinic. Let the child kick both legs together in the brace to get used to it.

Glossary