Flatfoot

By admin On Jan 21, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Flatfoot

Flatfoot

Kris J. Alden MD, PhD

Basics

Description

Flatfoot, or pes planus, is a deformity of the foot in which the normal medial longitudinal arch of the foot has been lost (1–4).
It may present as an asymptomatic
incidental finding or as a painful condition secondary to an associated
anatomic abnormality or pathologic condition of the foot.
Classification:
- Rigid versus flexible:
  - A flexible flatfoot lacks an arch only when patient is weightbearing, not when nonweightbearing or toe-standing.
  - A rigid flatfoot lacks an arch at all times.
- Pediatric versus adult:
  - Onset may indicate underlying potential cause.

Epidemiology

Incidence

Congenital flexible flatfoot after infancy:
- Is a trait that often runs in families, although the pattern of inheritance is not known
- Is present in ~15% of adults (5)
Tarsal coalition, the most common type of congenital rigid flatfoot, is inherited in an autosomal dominant pattern (6).
- The exact overall incidence is unknown, but it is <1% (7).
PTT deficiency is the most common cause of acquired flatfoot in adults, although its precise incidence is not known.
The exact incidence of other patterns of acquired flatfeet is not known.

Risk Factors

For persistent congenital flexible flatfoot: Other family members with the same condition
For congenital rigid flatfoot secondary to tarsal coalition: Female gender and other family members with the same condition
For acquired flexible flatfoot secondary to PTT synovitis or rupture: Hypertension, diabetes, and a history of trauma
Other conditions that can lead to flatfoot:
- Tight Achilles tendon
- Neurologic diseases (e.g., poliomyelitis, spina bifida, myelodysplasia, NF, stroke)
- Osteoarthritis, posttraumatic arthritis, or inflammatory arthritis
- Charcot arthropathy secondary to diabetes or other peripheral neuropathy

Etiology

Congenital flexible flatfoot and tarsal coalition are the result of genetic inheritance.
PTT dysfunction is secondary to tendon degeneration and attenuation.
Flatfoot deformity from Charcot neuroarthropathy is secondary to bone fragmentation, resorption, and fracture.
Other causes to consider: Congenital vertical talus, peroneal spastic flatfoot, and trauma (8–12)

Diagnosis

Signs and Symptoms

Flatfoot with low or no arch
Pain over medial arch
Deformity may progress with time.
May be exacerbated by walking, sports, high level of activity, or traumatic event
Abnormal shoe wear pattern

History

The onset of deformity, family history,
associated diseases, activity level, and history of previous trauma
should be noted for all patients.
The patient or parents may complain of
tenderness and swelling along the medial part of the foot, a diminished
endurance in the foot, a decreased ability to participate in sports,
and, eventually, a progressive difficulty in ambulating.
Increased wear on medial aspect of the shoe
Pediatric flatfoot deformity often is present from an early age.
Adult acquired flatfoot caused by
arthritis or rupture of the PTT presents as a gradual, progressive
aching and swelling along the medial aspect of the foot and ankle.

Physical Exam

Of primary importance is the determination of whether the condition is rigid or flexible.
- Rigid flatfoot:
  - Loss of the normal longitudinal arch of the foot at all times
  - Restricted motion of the hindfoot
- Flexible flatfoot:
  - Loss of arch only on standing on the
    affected foot, with reconstitution of the arch when the foot is
    dependent or when the patient toe-stands
  - Normal motion of the hindfoot
Increasing severity is associated with forefoot abduction and the “too many toes” sign when the patient is viewed from behind.
Inversion against resistance may be absent or diminished in patients with PTT dysfunction.
- The patient may have pain or difficulty when attempting a single-limb heel rise on the affected side.
The foot should be inspected for deformity or swelling and then palpated for tenderness.
Gait pattern should be assessed.
- An antalgic gait may indicate a painful condition such as arthritis or tendinitis.
- The patient may have impaired propulsion with PTT abnormality.
- An awkward, foot-slapping gait may suggest a neurologic or neuromuscular disease (e.g., spina bifida or poliomyelitis).
The Achilles tendon should be examined to test whether the heel cord is tight.

Tests

Imaging

Radiography:
- 3 standing radiographic views of the
  patient’s ankle (AP, lateral, and mortise) and 3 views of the patient’s
  foot (AP, lateral, and oblique) should be obtained.
- The calcaneal pitch is diminished and may approach 0° with more severe flatfoot deformity.
- The talus-1st metatarsal angle increases with loss of arch.
  - This angle should normally be 0° with the talus and metatarsal collinear.
  - Angle measurements: ≤15°, minor pes planus deformity; 15–30°, moderate deformity; >30°, severe deformity
- When tarsal coalition is suspected:
  - Assess oblique radiograph for a calcaneonavicular coalition.
  - Obtain a CT scan to rule out a talocalcaneal coalition.
- Assess the degree of hindfoot or midfoot arthritis.
- Rule out bony fragmentation indicative of Charcot arthropathy.
An MRI scan may be useful for visualizing PTT abnormality.

Pathological Findings

Secondary to underlying cause:
- Charcot arthropathy: Fragmentation, resorption of bone
- PTT dysfunction: Degeneration, tearing, hypertrophy
- Tarsal coalition: Fibrous, fibrocartilaginous, or osseous coalition

Differential Diagnosis

Pediatric flatfoot:
- Benign flexible flatfoot
- Tarsal coalition
- Congenital vertical/oblique talus
- Accessory navicular
Adult acquired flatfoot:
- PTT dysfunction or tear
- Midfoot arthritis
- Charcot arthropathy
- Neuromuscular disorders

P.139

Treatment

General Measures

No treatment needed if asymptomatic
Pediatric:
- Benign flexible flatfoot:
  - Shoes with good arch support
  - Consider orthotic device (e.g., prefabricated or custom-made medial arch support).
- Tarsal coalition:
  - Initially, immobilization with a below-the-knee cast or boot brace
  - Rest and temporary activity restriction
- Flatfoot secondary to a tight Achilles tendon may be relieved by physical therapy and heel-cord stretching.
Adult:
- PTT dysfunction or tear:
  - NSAIDs and rest
  - Short-term immobilization with a below-the-knee cast or boot brace
  - Long-term maintenance with custom orthotic arch support or ankle-foot orthosis (brace)
  - Injection of corticosteroids is not recommended because it may weaken or rupture the tendon.
  - Weight loss
- Midfoot arthritis:
  - Orthotic arch support
  - NSAIDs
  - Foot wear modifications (e.g., rocker-bottom and steel shank)
  - Intra-articular corticosteroid injections
- Charcot arthropathy:
  - Acutely: Total contact cast and restricted weightbearing
  - Long-term: Orthotics and/or bracing
- Surgical treatment is indicated for failure of nonoperative treatment.

Special Therapy

Physical Therapy

Physical therapy can be used to increase ankle and foot ROM and to stretch a tight Achilles tendon.
Orthotists can fabricate appropriate orthotic devices.

Medication

NSAIDs:
- Can be used if swelling and pain are substantial
- Are most useful for acute injuries or for patients with posterior tibial tendinitis.

Surgery

Indicated for failure of nonoperative treatment, progression of deformity, or instability (13)
- Surgical treatment may entail fusion, osteotomies, and possible soft-tissue procedures.
- Age, activity level, degree of deformity, and comorbid conditions play a role in determining the extent of surgical treatment.
Pediatric flexible flatfoot:
- Surgical treatments usually consist of
  osteotomies that realign the foot to correct valgus and improve
  mechanical alignment of the foot and ankle.
Rigid flatfoot from tarsal coalition:
- Resection of tarsal coalition with interposition of fat or muscle
- For patients with talocalcaneal coalition
  involving >50% of the joint surface or those with degenerative joint
  arthritis, subtalar arthrodesis is indicated.
Flatfoot secondary to a tight Achilles tendon:
- Tendon lengthening involves a Z-lengthening procedure or partial sectioning of the tendon.
Acquired flatfoot secondary to PTT synovitis:
- In early stages of the disease, synovectomy may be sufficient.
- Flexible deformities are corrected with
  tendon transfers, calcaneal and midfoot osteotomies, and/or limited
  hindfoot arthrodesis.
Fusion is necessary for arthritis or rigid flatfoot deformity.

Follow-up

Prognosis

Most patients do not develop progressive deformities and do not need corrective surgery.

Complications

Most patients have little risk of complications with nonoperative treatment.
1 major exception is patients with PTT dysfunction (acquired flatfoot) because they may develop a rigid flatfoot.

Patient Monitoring

Patients should be followed at 3-month intervals to
monitor their discomfort and function and to check whether their
deformity is stable or progressive.

References

1. Chang FM. The flexible flatfoot. Instr Course Lect 1988;37:109–110.

2. Chu IT, Myerson MS, Nyska M, et al. Experimental flatfoot model: the contribution of dynamic loading. Foot Ankle Int 2001;22: 220–225.

3. Jones LJ, Todd WF. Abnormal biomechanics of flatfoot deformities and related theories of biomechanical development. Clin Podiatr Med Surg 1989;6:511–520.

4. Kitaoka HB, Ahn TK, Luo ZP, et al. Stability of the arch of the foot. Foot Ankle Int 1997;18: 644–648.

5. Gould N, Schneider W, Ashikaga T. Epidemiological survey of foot problems in the continental United States: 1978–1979. Foot Ankle 1980;1:8–10.

6. Leonard MA. The inheritance of tarsal coalition and its relationship to spastic flat foot. J Bone Joint Surg 1974;56B:520–526.

7. Palladino SJ, Schiller L, Johnson JD. Cubonavicular coalition. J Am Podiatr Med Assoc 1991;81:262–266.

8. Harris
EJ. The oblique talus deformity. What is it, and what is its clinical
significance in the scheme of pronatory deformities? Clin Podiatr Med Surg 2000;17:419–442.

9. Hefti F. [Foot pain]. Orthopade 1999;28: 173–179.

10. Kumar SJ, Cowell HR, Ramsey PL. Vertical and oblique talus. Instr Course Lect 1982;31: 235–251.

11. Sullivan JA. Pediatric flatfoot: evaluation and management. J Am Acad Orthop Surg 1999;7: 44–53.

12. Tonnis D. [Skewfoot]. Orthopade 1986;15: 174–183.

13. Henceroth WD, II, Deyerle WM. The acquired unilateral flatfoot in the adult: some causative factors. Foot Ankle 1982;2:304–308.

Miscellaneous

Codes

ICD9-CM

734.0 Acquired flat foot
754.61 Congenital flat foot

Patient Teaching

Patient education is crucial because cosmesis in the absence of symptoms is not an appropriate indication for surgery.
Stretching exercises can help patients
with tight Achilles tendons, and foot orthoses may be useful for
patients who want to be active.

FAQ

Q: What are 3 causes of flatfoot deformity in pediatric patients?

A: Benign flexible flatfoot, tarsal coalition, and congenital vertical talus.

Q: What are 3 causes of flatfoot deformity in adults?

A: PTT dysfunction (most common cause of adult acquired flatfoot), neuroarthropathy, and degenerative or inflammatory arthritis.