Posterior Tibial Tendon Dysfunction

Introduction

In the early stages conservative treatments are regularly employed as a first-line treatmentand  can significantly improve the quality of life for patients, function and reduce pain.

Anatomy

Tibialis posterior originates posterior to the tibia in the deep compartment of the calf.  It travels down and passes through the posteromedial malleolar groove, where it is held in place by the flexor retinaculum.  An area of hypovascularity just distal to the medial malleolus may contribute to degenerative changes in the tendon.  The tendon primarily inserts onto the navicular tuberosity with slips fanning out to insert into the 2nd to 4th metatarsals, the plantar surface of the cuneiforms and the cuboid.

Function

The posterior tibial tendon passes posterior to the ankle axis and medial to the subtalar joint axis.  Its actions are to invert the midfoot (acting across the talonavicular and calcaneocuboid joint) and plantarflex the foot.  The tendon does act upon the hindfoot even though it has no direct attachment on the calcaneus via ligamentous structures such as the spring and deep deltoid ligament.

It is seen as the main dynamic stabiliser of the hind foot against hindfoot valgus and is integral in the stiffness of the midtarsal joint in making the foot a rigid lever.

PTTD

PTTD is a chronic condition ranging from early swelling and pain to chronic inflammation and potentially rupture.  As the condition progresses and tendonopathy develops, this can cause the tendon to degenerate, gradually elongate and develop interstitial tears.  This gradual loss of strength and elongation of the tendon causes several knock-on effects.

The lack of support provided by the posterior tibial tendon will allow the medial longitudinal arch to sag, causing an increase in tension in the secondary supporting structures of the arch.  Over time, repetitive loading will cause elongation and provide less of a supporting force.  The loss of these secondary support structures will allow the hindfoot to adopt an increasing valgus posture.

As the calcaneus progressively everts the ground reaction force (GRF) acts increasingly lateral to the subtalar joint axis.  This increases the GRF's lever arm and the pronatory moments around the subtalar joint.

As the posterior tibial tendon fails to invert the hindfoot during mid to late stance, the Achilles tendon insertion remains lateral to the subtalar joint axis.  As the calf contracts, it will further evert the calcaneus causing the midtarsal joint to become less stiff in late stance.  Causing the actions of tricep Surae to act at the midtarsal joint rather than with the long lever arm at the metatarsal heads.  This can lead to a progressive shortening of the TA, which will put further pressure on the posterior tibial tendon and secondary support structures.

A tight calf and achilles can contribute to developing acquired flat foot and PTTD by putting extra strain on the posterior tibial tendon due to increased pronatory moments around the sub-talar joint.  Tightness in the calf will cause a reduction in available dorsiflexion at the talocrural joint, which is needed during the second rocker.  As the talocrural joint does not have the motion, the subtalar and midtarsal joint will start to provide some of the needed sagittal plane motions.

As the posterior tibial tendon slowly lengthens and weakens, it has been suggested that it will allow peroneal brevis to function with gradually reducing opposition.  This could create a dynamic abduction and eversion force creating forefoot abduction and a shortening of the lateral column.

Symptoms of Posterior Tibial Tendon Dysfunction

• Pain and swelling along the Medial (inside) ankle or arch.
• Pain that may increase with activities like standing or walking.
• Pain when standing on tip toes, increasing on single heel raise.
• Difficulty walking on uneven surfaces.
• Difficulty walking up and down stairs.
• New or unusual or uneven wear on footwear

Stages of Posterior Tibial Tendon Dysfunction

• Medial pain and swelling
• Flexible Hindfoot
• Can perform single leg standing heel raise with heel inversion (8-10)
• May feel affected side feels weaker / painful
• Mild weakness of tibialis posterior on muscle testing
• Minimal to no deformity present
• Too many toes sign negative (should be 1.5-2 toes visible)

Stage 2a

• Evolves from stage 1 over several months or years
• Everted calcaneus in weight-bearing
• Normal foot position in non-weight bearing
• Medial pain increases in severity and distribution even during rest
• Hindfoot still flexible
• +/- ability to perform heel rises
• Marked weakness of tibialis posterior
• +ve too many toes sign  (Forefoot abducts at midtarsal tarsal joint)

Stage 2b

In addition to 2a

• Lateral pain (sinus tarsi, subfibular, cuboid)
• Midfoot pronated

Stage 3

• Significant eversion of calcaneus
• Lateral pain (sinus tarsi, subfibular, cuboid ) predominates (medial pain still present)
• Fixed irreducible pes planovalgus deformity
• Cannot perform a heel rise
• Significant forefoot abduction at midtarsal joint (too many toes sign)
• Appears severely flat
• Forefoot varus / supinatus
• No obvious ankle abnormalities

Stage 4

• Hindfoot rigid with fixed irreducible pes planovalgus deformity
• Degeneration of ankle
• Valgus angulation of talus confirmed on x-ray
• Tibialis posterior elongation and degeneration
• Pain medially, laterally or both
• Cannot perform a heel rise
• Significant forefoot abduction at midtarsal joint (too many toes sign)
• Arthritic changes in foot and ankle

Orthotic Treatment of PTTD / Adult Acquired Flat foot

Orthotic Treatment of PTTD / Adult Acquired Flat foot

The Aim of Orthotic treatment of PTTD should focus on creating a supinatory moment about the subtalar joint to prevent the condition's progression in line with tissue stress theories. Using Stock and Modular insoles in the early stages (I and 2a) is often cost-effective in alleviating symptoms and preventing degeneration. As the condition progresses, more aggressive and supportive orthoses are recommended.

Orthotic Treatment Options

Sense Insoles

Sense Modular Insoles are a good first option to provide relief without taking too much room in the shoe. We would suggest the Standard Shell with medial wedge plus Kirby Skive. Our Clinicians also recommend asking for the wedge to be extended into the arch to provide increased supination resistance.

Slimline Arch Support Insoles Full Length Blue

This stock insole has an increased heel cup and the ability to have wedging added by our trained technicians or chairside. Its composite nature provides a good level of support and supination resistance.

 Heel plateau Insole

The heel plateau insole aims to provide maximum stability together with optimal comfort. The 'Plateau' is an extended support surface that provides stability and improves force transmission onto the sole of the shoe. The heel plateau also features an integrated rolling edge that supports controlled step initiation, thus reducing the speed of pronation. The underside can ground to add a heel wedge up to around 3-4 degrees or added in a suitable material to increase over this.

Football insole

The fitting of insoles in football boots can prove difficult due to the narrow nature of the waist of the boot and limited forefoot depth. Players also feel they want their foot to hit the ball first, not the inside edge of the insole. The Football insole is our recommendation for use in football or any sport that uses narrow boots. Like all our insoles, they can be adapted with wedging to increase the forces and either we can do this for you, or you can do it yourself chairside.

When more support is required the Carbon Edition football provides increased support thanks to its Prpreg Carbon Fibre construction.

Do you treat Flat foot or PTTD privately?

Our Clinic will assess people with foot problems in both Edinburgh and Glasgow. Appointments can be booked via our dedicated clinic site.