Foot and ankle
Foot reconstruction requires a clear understanding of each section of the foot. From heel to toe, the foot is divided into three parts: the forefoot, the midfoot and the hindfoot.
Each section is made up of the foot several bones:
- Forefoot: metatarsal bones and phalanx
- Midfoot: cuneiforms, scaphoid (navicular bone) and cuboid
- Hindfoot: talus and the calcaneus (heel bone)
Deformities are measured according to the planes of the limb and to the 3 parts of the foot:
Forefoot and Midfoot:
- Supination: where the foot joint is turned inwards and upwards
- Pronation: where the foot turned sideways
- Flexor: the forefoot points downwards and arch is curved too much. This is called “cavus foot”.
- Extension of the foot: the forefoot points upwards.
- Abductor: the forefoot deviates to the side.
- Adductor: the forefoot deviates internally.
- Varus: heel is turned inwards
- Valgus: heel is turned outwards
- Equinus: where the front part of the hindfoot points downwards
- Plantaris: where the back part of the foot points downwards
- Internal rotation: the hindfoot is turned inwards
- External rotation: the hindfoot is turned outwards
There are cases where deformities range across all parts of the foot. These combined deformities include:
- Cavus foot: where both the hindfoot and the forefoot points downwards.
- Flat foot: where the foot arch is flat
- Adductor-cavovarus foot
- Clubfoot: combination of the 3 deformities above
- Metatarsus adductus
- Z-shaped foot or “skewed foot”: where the deformities span all 3 parts of the foot.
For foot reconstruction, a full and thorough analysis of deformities in each part of the foot must be conducted in order for a surgeon to achieve an end result close to a normal anatomy.
Bone or soft-tissue ?
Corrections to bone and soft tissue of the foot depends on the patient’s age. In the young child, soft-tissue, such as tendons and joint capsules surgery is the preferred method, while in the older child, bone surgery is favored.
For a young child, bones are mostly cartilaginous, which is easily modified and adapted because the cartilage is soft. However on a child of 5 or over, the joint surfaces are fixed and calcified. At this age, osteotomies are performed to realign the joint surfaces, where the bone will heal like a fracture, allowing the foot to keep the shape after surgery.
Foot correction operations are performed either open (which can produce large scars) or percutaneously (through a small/stab incision). The choice depends on the deformity and type of fixation required.
When deformities are small, fixation types can include pins, staples, and casts. For larger bone deformities, external fixators are a better alternative.
For ankle correction, surgery is only performed after a full evaluation of the limb from hip to toe.
For a patient with clubfoot, the deformity is discovered at birth, as both feet will be turned inwards and upwards. Correcting this deformity involves a rehabilitation program which uses small splints to correct rotation. In some cases however, sequential casts are used early. The choice of technique depends on the severity of the deformity and the response to the initial rehabilitation. Treatment may also combine physiotherapy, derotation splints and surgery.
After 3 months of treatment, the extent of response will determine whether surgery is required. In the case of residual deformities, operative treatment is generally performed around 10-12 months.
Minor alignment problems of the foot bones
All malalignment problems can be treated, but usually in adult or an older child cases. As bones are not yet fully formed at a younger age, surgery for children is not performed unless there are specific problems, such as a child cannot wear shoes or experiences too much pain.
Recurrent clubfoot is more complex as patients often have to undergo several operations. Some corrections can be performed acutely, while others need more gradual treatment. For multiple deformities, each irregular bone structure should be corrected to the end goal of full foot realignment.
Surgery should correct all three parts of the foot. To correct the hindfoot, the talus and calcaneus need to be realigned at the level just in front of the tibia, with an external fixator helping to aid derotation of the foot gradually. Mounting of the external fixator for an outwards derotation is quite difficult to place, but it can fix multiple problems.
Corrections do not always require external fixators, treatments including an osteotomy fixed with pins and a cast are adequate.
For metatarsus adductus, the forefoot turns inwards. Correction is usually performed around the age of 5 to 6 years using osteotomies and joint realignment in a soft-tissue surgery.
Hallux valgus of the young patient
Hallux valgus is formed by deformities of the bone axis.
Generally, unless the deformity causes sever pain, there is no surgical correction for flat foot.