Clinical presentation of static flatfoot
Patients complain of pain that increases towards the evening after prolonged standing or walking and subsides after rest. Often, edema and pastosity appear by the end of the day.
Pain sensations are localized in strictly defined zones:
- On the sole (center of the arch, inner edge of the heel) and the dorsum of the foot (between the talus and navicular bones).
- Under the malleoli and between the heads of the metatarsal bones.
- In the calf muscles (due to overload and imbalance), knee, and hip joints.
- In the thigh (overstrain of the iliotibial tract) and lower back (compensatory hyperlordosis develops).
With pronounced deformity (grade II–III), the foot appears elongated and widened in the middle, the longitudinal arch is lowered, and the foot is in a pronated position. The gait becomes clumsy, the toes are turned significantly outward during walking, and movements in the joints of the foot may be restricted.
X-ray diagnostics of longitudinal flatfoot
To accurately assess the degree of flattening, a lateral projection radiograph is performed. The main condition is that the image is taken standing on one foot so that the foot experiences full load. The image must capture the foot and the lower 4–5 cm of the lower leg.
On the image, a triangle is constructed using three points: the lower edge of the cuneonavicular joint, the plantar contour of the head of the first metatarsal bone, and the lower contour of the calcaneal tuberosity.
Two parameters are evaluated:
- Longitudinal arch angle ($\alpha$) — normally 125–130°. In pathology, it increases.
- Arch height ($h$) — a perpendicular from the cuneonavicular joint to the support line. Normally 39–36 mm, decreased in flattening.
| Grade | Arch angle ($\alpha$), degrees | Arch height ($h$), mm |
|---|---|---|
| I | 131 — 140 | 35 — 25 |
| II | 141 — 155 | 24 — 17 |
| III | $\ge$ 155 | < 17 |
Transverse splayfoot and Hallux valgus
In adults, transverse flatfoot is considered irreversible because the ligamentous apparatus cannot cope with the constant static load. The degree of deformity is assessed by the deviation angle of the first metatarsal bone, drawing axes through the first and second metatarsal bones, as well as the proximal phalanx of the great toe.
Valgus deformity of the great toe (Hallux valgus) is accompanied by arthrosis of the metatarsophalangeal joints, chronic bursitis, and the appearance of exostoses.
Pathogenesis of the loss of foot support:
- Muscle imbalance develops, tendons shorten and tighten.
- The head of the first metatarsal bone slips off the medial sesamoid bone.
- Bearing load pathologically shifts to the heads of the middle metatarsals.
- Painful callosities and corn form on the sole, making walking extremely difficult.
Treatment can be conservative (orthoses, orthopedic shoes, pads, and spacers for grade I) or surgical.
Preoperative preparation and concomitant pathologies
Before surgery, all patients are prescribed a standard panel: general blood and urine tests, biochemistry, coagulogram with INR, blood type and Rh factor, as well as hospital screening for infections (Treponema pallidum, hepatitis B and C, HIV).
Children require special attention. In children, foot deformity may not be isolated, but a manifestation of systemic diseases: hereditary (Down, Marfan, Ehlers-Danlos syndromes) or neuromuscular (cerebral palsy, myodystrophies). In such cases, an expanded diagnostic workup and management adjustment are required.
If congenital vertical talus is suspected (occurring in 1 of 100,000 newborns), functional imaging is performed. The diagnosis is confirmed if, at maximum dorsiflexion, the heel remains in an equinus position, and at plantarflexion, the axis of the talus and the first metatarsal bone does not align.
The pathogenesis of Hallux valgus is easy to remember via the "bowstring effect": due to muscle imbalance, tendons shorten and tighten like a bowstring, pulling the great toe and causing the metatarsal head to slip off the sesamoid bone.
Class and exam questions
How to properly perform radiography to assess the longitudinal arch?
The image is taken in a lateral projection capturing the foot and 4–5 cm of the lower leg. The patient must stand on one foot to ensure full static load.
Why does the lower back hurt in flatfoot?
Due to foot flattening, the biomechanics of the entire lower limb changes. This leads to the formation of compensatory hyperlordosis, which causes overload and lower back pain.
How to confirm congenital vertical talus?
Functional radiographs are performed. The diagnosis is confirmed if, at maximum dorsiflexion, the heel remains in an equinus position, and at plantarflexion, the axis of the talus and the first metatarsal bone is not restored.
What else to study on this topic
- Conservative treatment: types of orthoses and specialized orthopedic footwear.
- Surgical correction methods for transverse flatfoot and Hallux valgus.
- Differential diagnosis with neuromuscular diseases (cerebral palsy, myodystrophies).
- Evaluation of coagulogram and INR prior to surgical intervention.
- Radiological assessment of foot deformity severity by deviation angles (Table 57.2).
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