Tibialis posterior dysfunction

Tibialis posterior dysfunction is common, mostly affecting middle-aged and elderly females, and can progress to adult-acquired flatfoot disease. 

Pathology

Dysfunction occurs secondary from repetitive overloading resulting in degeneration, which occurs in the typical continuum of tenosynovitis and tendinosis progressing to partial and full-thickness tendon tears. Elongation can also occur without tearing, with as little as 1 cm of elongation resulting in dysfunction ¹.

Tibialis posterior can tear in its ¹:

• supramalleolar part (uncommon)
• retromalleolar part
• inframalleolar part (most common)

Aetiology

Tibialis posterior dysfunction can be secondary to ³:

• trauma
• underlying disease, e.g. inflammatory arthropathy
• idiopathic
• functional, e.g. tarsal coalition

Risk factors

• congenital pes planus
• obesity
• diabetes
• gout
• inflammatory arthropathy
• hypertension
• corticosteroid use

Radiographic features

Plain radiograph

Secondary features of tibialis posterior dysfunction include ¹:

• soft tissue swelling
• navicular tuberosity enthesopathy
• retromalleolar groove bone hypertrophy
• in some cases, there may be subtalar arthritis

Ultrasound

• tendon sheath effusion and diameter >7 mm reflects tenosynovitis ¹