Tibialis Posterior Tendon Dysfunction

The tibialis posterior tendon inserts predominantly onto the medial navicular and serves to support the medial arch of the foot

Aetiology

  • Cause usually unclear
  • Tibialis posterior tendon dysfunction is the most common cause of aquired flat foot in adults

Risk factors

  • Obese middle aged female
  • Risk increases with age
  • Hypertension
  • Diabetes
  • Steriod injection
  • Seronegative arthropathies
  • Idiopathic tendonosis

Pathophysiology

  • The tendon is under repeated stress and particularly with degeneration can develop tendonitis, elongation and eventually rupture
  • Usually present for years prior to diagnosis
  • Elongation or rupture leads to loss of the medial arch with resulting valgus of the heel and flattening of the medial arch of the foot

Clinical presentation

  • Pain and/or swelling posterior to medial malleolus - very specific
  • Change in foot shape
  • Diminished walking ability/balance
  • Dislike of uneven surfaces
  • More noticable hallux valgus
  • Lateral wall 'impingement' pain
  • Midfoot and ankle pain

Classification

  • Type I: swelling, tenderness, slightly weak muscle power
  • Type II: planovalgus, midfoot abduction, passively correctable
    • 'Too many toes', cannot single heel raise
  • Type III and IV: fixity and mortise signs

Investigations

  • Clinical diangnosis

Management

  • Physiotherapy
  • Tendonitis should be treated with a splint with a medial arch support to avoid rupture
  • Orthoses to accommodate foot shape, bespoke footwear
  • If this fails to settle symptoms, surgical decompression and tenosynovectomy may prevent rupture
  • DO NOT use steriod injections
  • Surgical options for rupture:
    • If no secondary OA present, a tendon transfer may be performed to try to prevent secondary OA with a calcaneal osteotomy to reduce stress
    • Once OA ensues, the most appropriate surgical treatment if symptoms are severe is arthrodesis