Flatfoot is a common condition with approximately 30% of people being born with flatfeet.  However, many patients are born with a normal arched foot which progressively collapses during their lifetime.  This condition is known as Adult Acquired Flatfoot Deformity (AAFD) and is often symptomatic and can become debilitating.  Posterior Tibial Tendon Insufficiency (PTTI) is the most common cause of AFFD and usually presents in middle aged females.  Due to the progressive nature of PTTI, surgical intervention is often required, however early recognition of this condition can often be managed non-operatively.

History

Patients often present at variable stages of PTTI.  The history should focus on the patient’s pain, joint, functional and treatment profiles along with risk factors.

Pain profile

• Medial ankle/ Foot pain
• Lateral ankle pain (late)
• Association with activity

Joint profile

• Medial ankle/foot weakness (Early)
• Progressive loss of arch/ change of shape
• Swelling
• Stiffness

Functional Profile

• Ability to work, walk and stand
• Ability to wear shoes
• Activities

Treatment profile

• Physiotherapy and Orthotics
• Pharmacology and Injections

Risk Factors

• Female
• Obesity
• Diabetes
• Inflammatory arthropathy
• Increasing age
• Corticosteroid use

Examination

When suspecting PTTI, clinical examination is essential in diagnosis and staging.  The keys to the exam is to assess if the deformity is fixed or flexible, if osteoarthritis is present and the relative power of the tendons.

Inspection

• Medial arch for collapse
• Posterior tibial tendon for inflammation and synovitis.
• Hindfoot alignment which is often in valgus
• Forefoot alignment which is often abducted

Palpation for areas of tenderness

• Tibialis posterior tendon
• Ankle joint
• Talonavicular joint
• Calcaneocuboid joint
• Sinus tarsi (subtalar joint)

Flexibility

• Hindfoot with a double heel rise.
  • If the hindfoot swings into the varus on double heel rise it is noted as flexible.

Power and fatiguability of posterior tibial tendon

• Single heel rise

Investigation

X-rays and MRI complement the clinical examination.  X-rays assess alignment while demonstrating areas of osteoarthritis.  MRI’s further delineate the degree of osteoarthritis while assessing the quality of soft tissue structures such as the posterior tibial tendon and spring ligament.

X-rays

• Weightbearing AP/Lateral Foot and Ankle (Figure 1 A,C,D)
• Weightbearing Saltzman Hindfoot alignment view (Figure 1B)

MRI

• Foot and ankle

Staging and Management

Staging the degree of PTTI aids in the management of the condition.  This is based on the Johnson and Strom classification.  Early stages are often treated non-operatively with up to 80% success.  Joint preserving surgeries are suitable for flexible deformities while fixed deformities are treated with fusion procedures.

STAGE 1

• Inflamed tendon with posteromedial ankle pain
• NO DEFORMITY with maintained arch
• ABLE to single heel raise but fatigued on repetition.

Non-operative        

• Physiotherapy, Orthotics, Immobilisation

Operative

• Synovectomy

STAGE 2

• FLEXIBLE flatfoot deformity (Arch Collapse and hindfoot valgus) with no arthritis
  • Stage 2a – Normal Forefoot
  • Stage 2b – Abducted Forefoot (Figure 1A)
• UNABLE to single heel raise

Non-operative

• Physiotherapy, Orthotics, Immobilisation

Operative

• Posterior Tibial Tendon Reconstruction with FDL transfer
• Spring Ligament Repair
• Calcaneal Osteotomy +/- Lateral Column Lengthening

STAGE 3

• FIXED FLAT FOOT DEFORMITY with subtalar osteoarthritis (Figure 1D)

Operative

• Double Arthrodesis (Subtalar and Talonavicular joint) (Figure 2)
• Triple Arthrodesis (Subtalar, Talonavicular and Calcaneocuboid Joint)

STAGE 4

• FIXED FLAT FOOT DEFORMITY with pan-talar osteoarthritis

Operative

• Pan-talar fusion
• Double/triple arthrodesis + total ankle replacement.

Summary

Posterior Tibial Tendon Insufficiency is the most common cause of adult acquire flatfoot deformity.  Recognizing PTTI in its early stages may help prevent progression and allow for successful non-operative management.  However, due to the natural history of this condition and often late presentation, surgical intervention is frequently required.  Modern surgical techniques are utilized to minimize wound complications, increase fusion rates while providing the patient with a painless, functional foot.  Due to the complex nature of the disorder most operative procedures for this condition are required to be individualized on a cases by case basis.