Tibialis posterior tendon dysfunction

• often this condition is seen in conjunction with over-pronation of the foot - about 70% of patients with this condition are females who are overweight, and have previous underlying problems of overpronation
• tibialis posterior reduces and controls pronation of the foot - thus, when a foot over-pronates then this increases forces on this muscle and the tendon becomes irritated, especially as it skirts around the medial malleolus, resulting in pain, inflammation and swelling
• the patient may complain of pain in the sole of the foot, around the ankle and up the leg. Over time the tendon will degenerate and may ultimately rupture - if this occurs then arch will collapse and present as a talo-navicular bulge on the medial aspect and laterally, when viewed behind as 'too many toes' (1)

Treatment:

• conservative
  • in the early stages
    • NSAIDs, good supportive footwear, orthoses and calf-stretching exercises can all help reduce symptoms
    • in the acute stages a plaster plast can be applied to rest the tendon
    • if tenosynovitis alone, a guided local anaesthetic and cortisone injection may be of benefit.
• surgical
  • decompression of the tendon sheath and repair of longitudinal tears may be sufficient for patients without associated foot deformity
  • note that addressing the underlying foot deformity is often necessary to prevent recurrence
    • tendon transfer in combination with an osteotomy of the calcaneus and lengthening of the calf muscle (gastrocnemius) has demonstrated good results
    • in the severest cases there is a requirement for even more extensive surgery, with joint fusion – even triple arthrodesis involving the rearfoot – and possibly implants into the sinus tarsi to limit motion
    • the extent of surgery required for this condition makes early diagnosis and aggressive conservative treatment essential if this is to be avoided

Reference:

1. Rheumatic Disease in Practice (September 2001). The therapeutic scope of modern podiatry. Issue number 6, Arthritis Research Campaign.
2. ARC. Common foot disorders. Hands On 2006;10:1-6.