L17 Introduction to surgery of the foot and ankle

Question 1

Why is the foot important

Answer 1

• To ensure that we have a smooth gait cycle

- If foot anatomy is abnormal foot function is compromised

Question 2

Sections of the foot

Answer 2

• Hindfoot
• Midfoot
• Forefoot

Question 3

Basics of foot and ankle

Answer 3

• Have a natural hindfoot valgus

- Further valgus your midfoot and forefoot will compensate

Question 4

How can the natural hindfoot valgus be achieved surgically

Answer 4

Tendons

• Debridement
• Tenodesis
• Tendon transfer
• Direct repair

Ligaments

• Indirect repair
• Tendon transfer

Bone

• Osteotomy
• Exostectomy

Question 5

Aims of treating foot and ankle pathology

Answer 5

Is always to achieve a foot which is:

• Painless
• Plantigrade
• Structurally normal
• Functionally normal

Question 6

Achilles tendon

Answer 6

AKA heel cord
- The gastrocnemius, soleus and plantaris muscle unites to form a band of fibrous tissue which becomes the achilles tendon which attaches to the calcaneal tuberosity

• Largest and strongest tendon
• Approx 15 cm in length
• Plantarflexor of the foot

Question 7

Why is the achilles heel vulnerable to pathology

Answer 7

Unlike other tendons, it has no tendon sheath

It is surrounded by a paratenon

It has a poor blood supply

Blood vascularity weakest at the bone-tendon interface

Blood supply weakest at 2 to 6 cm form the calcaneal attachment

Question 8

Achilles tendon - blood supply

Answer 8

1. posterior tibial artery (proximal and distal section)

2. Peroneal artery (supplies midsection)

Question 9

When might achilles rupture occur

Answer 9

• Occurs after a sudden forced plantarflexion to the foot

- Violent dorsiflexion in a planatar flexed foot

Question 10

Where does the achilles rupture occur usually

Answer 10

• Usually ruptures 4 to 6 cm above the calcaneal insertion in the hypovascular region

Question 11

Achilles rupture - treatment

Answer 11

• In functional bracing
• Surgery - end to end repair, VY advancement, failure to heal(tendon transfer)
• Trendon used is the one closest in proximity - flexor hallucis longus

Question 12

Surgical approach to the achilles

Answer 12

• Patient is prone or in lazy lateral position
• Landmarks: the malleoli and the achilles tendon - which is easily palpable
• Incision: longitudinal - slightly medially based(but can go laterally as well)

Question 13

Structure to avoid during surgery of the achilles

Answer 13

• Sural nerve laterally
• Avoid going medial to flexor hallucis longus (FHL) (easily identifiable as has muscle fibres at this level) - neurovascular bundle medially

Question 14

Location of tibialis posterior tendon

Answer 14

• Posterior aspect of interosseous membrane, fibula and tibia and has 9 insertions in the foot

Question 15

Tibialis posterior tendon - action

Answer 15

• Plantarflexes the ankle joint
• Principal invertor of the foot
• Adductus and supinates the foot

Question 16

Tibilalis posterior tendon - arterial supply

Answer 16

Arterial supply from the posterior tibial, peroneal and sural

• Has a watershed area around the medial malleoli

Question 17

Function of tibialis posterior tendon

Answer 17

• Stabilise lower leg
• Facilitates foot inversion
• Supports the foot’s medial arch
• Plays a critical role in hindfoot inversion during the gait cycle

Question 18

Presenting symptoms/signs of tibialis posterior insufficiency

Answer 18

• Post-malleolar pain
• Arch pain + aching
• Progressive flat foot deformity
• Forefoot problems: progressive hallux valgus, metatarsalgia, lesser toe deformities
• Rarely, tarsal tunnel syndrome

Question 19

How might tibialis posterior insufficiency typically present

Answer 19

1. Valgus hindfoot
2. Acquired flatfoot
3. forefoot abduction

Question 20

How might tibialis posterior insufficiency occur

Answer 20

• Either the tendon ruptures or stretches
• Only normally 1cm excursion so very little lengthening required to dysfunction
• Tears occur in the hypovascular zone 3-5cm proximal to insertion

Question 21

What is the most common cause of adult acquired flat foot

Answer 21

• Tibialis posterior insufficiency

Question 22

Causes of tibialis posterior insufficiency

Answer 22

• Trauma
• Chronic flat foot
• Inflammatory arthropathy
• Degenerative tendonopathy

Question 23

Two main groups affected by tibialis posterior insufficiency

Answer 23

• younger patients aged 30-40 with inflammatory arthropathy

- Older, typically female patients 50-60 years old with degenerative tears

Question 24

Tibialis posterior insufficiency - complaints

Answer 24

• Post-malleolar pain
• Arch pain + aching
• Progressive flat foot
• Forefoot problems: progressive hallux valgus, metatarsalgia, lesser toe deformities
• Rarely, tarsal tunnel syndrome

Question 25

Tibialis posterior insufficiency - examination

Answer 25

- Gait - Planovalgus foot - Heel remains in valgus on double foot tiptoe standing - Post-malleolar tenderness/swelling with no palpable tendon on resisted plantar flexion/inversion

Question 26

Single foot tiptoe test

Answer 26

Cannot stand on tiptoe on single foot if tibialis posterior not functioning - Tight TA in hindfoot neutral - Hindfoot/forefoot malalignment and its degree of correctability

Question 27

Tibialis posterior insufficiency - treatment (non-surgical)

Answer 27

- Analgesics - Shore wear modification - Orthortics - medial arch supports - Physiotherapy

Question 28

Tibialis posterior insufficiency treatment (surgery)

Answer 28

- Reconstruction (tendon transfer) | - Fusion(if secondary arthritis)

Question 29

Surgical approach to tibialis posterior tendon

Answer 29

Position - supine Landmark - tip of medial malleoli and the base of the navicular Incision - 10 cm longitudinal incision from tip of MM Internervous plane: none Dissection - avid damage to the long saphenous vein and nerve Divide the retinaculum and identify the tibialis posterior tendon by pullling on it FHL will plantart flex the freat toe and FDL will plantarflex the lesser toes

Question 30

Dangers of surgery on tibialis posterior tendon

Answer 30

- Saphenous nerve and the tibialis posterior tendon are particularly vulnerable