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Foot and Ankle

Basic anatomy

Foot reconstruction requires a 3-dimensional understanding of the different parts of the foot. From front to rear, it is divided into three parts: the forefoot (in the image below), midfoot and hindfoot.

The ankle is the joint between the bones of the leg (tibia inside and fibula outside) and the foot.

Picture: A 3D-CT-Scan of the foot of a young patient showing the forefoot (green), then midfoot (blue) and the hindfoot (red).

Each part of the foot has several bones:

• Forefoot: metatarsal bones and phalanx (19 bones)
• Midfoot: cuneiforms, scaphoid (navicular bone) and cuboid
• Hindfoot: talus (just below the tibia), and the calcaneum, or heel bone, below the talus

Deformities

Deformities are measured according to the reference planes of the limb and to the 3 parts of the foot:

Forefoot :

Frontal/coronal plane
- Supination: the lower surface of the foot is turned inwards to orient upwards
- Pronation: the lower surface of the foot turns on the lateral side
Sagittal plane
- Flexor: the forefoot points downwards; if the plantar arch is curved too much, it is called "cavus foot".
- Dorsiflexion or extension of the forefoot: the forefoot points upwards.
Transverse plane (ie, plane of the foot as seen from above):
- Abductor: the forefoot deviates to the lateral side
- Adductor: the forefoot deviates internally. Angulation is generally measured on the fifth arch (fifth metatarsal bone).

Midfoot :

Same as above

Hindfoot :

Frontal plane
- Varus: heel turns inwards
- Valgus: heel turns outwards
Sagittal plane
- Equinus: front part of the hindfoot points downwards
- Plantaris: back part of the foot points downwards
Transverse plane (ie, the plane of the foot itself)
- Internal rotation: hindfoot turns inwards
- External rotation: the hindfoot turns outwards

In addition to occurring in 3 planes for each of the 3 parts of the foot, deformities may be found in the 2 planes connecting the 3 parts of the foot ; i.e., the plane between the forefoot and the midfoot (which corresponds to the Lisfranc joint), and the plane between the midfoot and the hindfoot (Chopart joint). Combined deformities include:

  • Cavus foot, where both the hindfoot and the forefoot points downwards, increasing the normal arch of the foot
  • Flat foot, where the loading arch below the foot is flat
  • Adducto-cavo-varus foot, combining the 3 related deformities
  • Clubfoot, combining in addition to the 3 deformities described above, an equinus of the foot.
  • Metatarsus adductus, with or without supination
  • Z-shaped foot ("skewed foot"), where deformities seat at the planes between the 3 parts of the foot, with translations between them.
  • Foot reconstruction requires a thorough analysis of deformities in each part of the foot as well as between and among these parts. To achieve as close to a normal anatomy as possible, careful planning is required; the surgeon will have to adjust simultaneously or sequentially 11 planes of space (3 planes for each of the 3 parts of the foot + 2 connecting planes).

    Correction possibilities

    Bone or soft-tissue ?

    Corrections to either the bone or soft tissue of the foot depend on the patient's age. In a young child, bones are mostly cartilaginous. Cartilage is rather soft, and realigning bones through joints will generally be successful, as the cartilage shape will modify and adapt easily.
    After age 5 or 6 years, however, joint surfaces are fixed (bone is formed and calcified) and cannot adapt. At this age, osteotomies (bone sections) are performed to realign the joint surfaces. The sectioned bone will heal like a fracture and the axis between joint surfaces will be maintained, allowing the foot to keep the shape it obtains after surgery.
    In the young child, soft-tissue release (e.g., tendons, joint capsules) is the preferred method, while in the older child, bone surgery is favored.

    Scars

    Operations are performed either open (which can produce large scars) or percutaneously (through a small/stab incision). The choice depends on several parameters, including the deformity and type of fixation required.

    Fixation types

    When deformities are small, fixation types can include pins, staples, and casts ; when large, external fixators might be an alternative to other fixators. In this case, the corrections can be very large and achieved gradually.

    classic cases

    Ankle anomalies

    They combine axial deviations and / or degenerative changes. Surgical correction needs to be performed after full evaluation of the limb from hip to tip-toe. An example is provided below.

    Pictures above: A patient with a post-trauma degenerative osteo-arthritis of both ankle, and with foot deformities. An ankle replacement has been performed to regain the lost ankle motion. Re-alignments of the Calcaneus bone and of the upper tibia have been performed. The current limb alignment is perfect.

    Simple clubfoot

    In a patient with simple clubfoot, the deformity is observed at (or before) birth, with both feet turned inwards and upwards. To correct the deformity, a rehabilitation program is begun if the foot is supple and reducible to a large extent. Small splints are used with elastic bandages to correct rotation, varus, supination, and equinus. In some cases, sequential casts are initiated early (Ponsetti or equivalent techniques). Choice of technique depends both on the type and severity of the deformity and on the response to the initial rehabilitation.
    After 3 months of treatment, the extent of response will determine whether the foot can be fully corrected by soft-tissue release methods or whether surgery is required. In the case of residual deformities, operative treatment is generally performed at the age of 10-12 months.

    Pictures above: Spontaneous position of the feet with bilateral clubfoot.

    Depending on clubfoot severity and evolution, treatment may combine physiotherapy; use of continuous passive motion machines (e.g., Kinetic®); derotation splints, orthosis, casting; or surgery.

    Pictures above: Position of derotation splints. Note that molded splints allow correction of the adductor (which cannot be achieved by wood plates). Foot derotation should rotate the foot with respect to the thigh.

    Picture above: Position with correction of the foot in a cast. The foot should be turned outwards with respect to the thigh when the knee is bent 90°. A 90° flexion of the ankle should be associated with correction of the adductor of the foot (the foot should be straight) and of the varus of the heel (the heel should be slightly tilted outwards).

    Pictures above: Correction obtained showing a flexion of the ankle above 90°.

    Minor alignment problems of the foot bones

    All malalignment problems can be addressed, usually in the adult or an older child. Generally, because bones are not yet fully formed, surgery is not indicated in too young a patient unless there are specific problems, such as a child cannot wear shoes or experiences too much pain while wearing shoes.

    Recurrent clubfoot

    Recurrent clubfoot is more complex in that patients often have to undergo several surgeries. Deformities need to be analyzed according to the 3 foot parts; i.e., the 11 planes of deformity. Corrections should be planned separately for each deformity. Some corrections can be performed acutely ; others gradually. A majority, if not all, of each deformity should be corrected, with the goal of full foot realignment.

    Deformities that can occur include:

  • Hindfoot deformity, which is often a rotatory deformity that brings the calcaneum inwards
  • A varus of the hindfoot with equinus and cavus
  • A lateral translation of the foot
  • A supination-adductor of the forefoot
  • Pictures above: Recurrent clubfoot. Please, note the theoretical normal alignment of the foot (yellow line) and the actual foot axis (blue line): The hindfoot, midfoot and forefoot are turned inwards (talus axis: red line).

    Surgery should correct the 3 parts of the foot. To correct the hindfoot, the talus and calcaneum need to be sectioned and realigned at the level of their neck (just in front of the tibia). Fixation is often performed with an external fixator to derotate the foot outwards gradually. Mounting of the external fixator for an outwards derotation is quite difficult to achieve. However, the corrections that can be achieved may be large.

    Pictures above: Percutaneous osteotomy of the neck of the talus and calcaneus (left) and after setting of the external fixator (right).

    Corrections can be sometimes very important.

    Pictures above: Recurrent multi-operated clubfoot (left). Please note that he presents also a clubfoot on the other side, lighter. On the right, the partial correction of the foot, before final adjustment of the frame in operating room.

    Pictures above: Right clubfoot before correction (left picture: foot on the right). After surgical correction (left picture, foot on the left), the barefoot print is corrected, whilst it is still abnormal for the other foot).

     

    Corrections do not always require external fixators ; sometimes joint release and osteotomy fixed with pins and a cast is adequate.

    Pictures above: Recurrent clubfoot (5 previous operations) with lateral translation of the foot, false genu valgum and recurvatum, supination, and adductor of the foot.

    Pictures: Correction obtained with suppression of the false genu valgum-recurvatum and of the foot translation; foot alignment is good and the foot print normalized (note the corrected foot is the smaller one).

    Metatarsus adductus

    In metatarsus adductus, the forefoot turns inwards. Correction is performed at the age of approximately 5 to 6 years of age and associates osteotomies and joint realignment through a soft-tissue surgery.

    Pictures: Bilateral metatarsus adductus, full peroperative correction, then clinical and X-rays result.

    Hallux valgus of the young patient

    Hallux valgus is generally due to deformities of the bone axis. As a consequence, surgery is directed towards correcting these malalignments.

    Pictures above: Patient with a bilateral hallux valgus. Note the deviation of greater toes clinically and on x-rays. Correction was first achieved on the right side (left on the photo, taken 3 months previously). On x-ray, it is almost impossible to see the surgical site (the first phalanx has been shortened and the long metatarsal bone has been reoriented. On the left foot (right on the photo), surgery had been performed 3 weeks previously. The inflammatory healing response is still present and the bones are not yet fully fused, but the patient can walk and bear weight on this foot. On x-rays, the bone has not fused and the screws and pins have not yet been removed. In 2 months, surgery on the left side will be as barely noticeable as that on the right side.

    Flat foot

    Generally, unless there are severe and painful deformities, there is no surgical indication for flat foot.

    Pictures above: Patient with a bilateral flat foot. Growth non completed. No current surgical indication.