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)
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.
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
Rheumatic Disease in Practice (September 2001). The therapeutic scope of modern podiatry. Issue number 6, Arthritis Research Campaign.