L17 Introduction to surgery of the foot and ankle Flashcards
Why is the foot important
- To ensure that we have a smooth gait cycle
- If foot anatomy is abnormal foot function is compromised
Sections of the foot
- Hindfoot
- Midfoot
- Forefoot
Basics of foot and ankle
- Have a natural hindfoot valgus
- Further valgus your midfoot and forefoot will compensate
How can the natural hindfoot valgus be achieved surgically
Tendons
- Debridement
- Tenodesis
- Tendon transfer
- Direct repair
Ligaments
- Indirect repair
- Tendon transfer
Bone
- Osteotomy
- Exostectomy
Aims of treating foot and ankle pathology
Is always to achieve a foot which is:
- Painless
- Plantigrade
- Structurally normal
- Functionally normal
Achilles tendon
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
Why is the achilles heel vulnerable to pathology
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
Achilles tendon - blood supply
- posterior tibial artery (proximal and distal section)
2. Peroneal artery (supplies midsection)
When might achilles rupture occur
- Occurs after a sudden forced plantarflexion to the foot
- Violent dorsiflexion in a planatar flexed foot
Where does the achilles rupture occur usually
- Usually ruptures 4 to 6 cm above the calcaneal insertion in the hypovascular region
Achilles rupture - treatment
- 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
Surgical approach to the achilles
- 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)
Structure to avoid during surgery of the achilles
- Sural nerve laterally
- Avoid going medial to flexor hallucis longus (FHL) (easily identifiable as has muscle fibres at this level) - neurovascular bundle medially
Location of tibialis posterior tendon
- Posterior aspect of interosseous membrane, fibula and tibia and has 9 insertions in the foot
Tibialis posterior tendon - action
- Plantarflexes the ankle joint
- Principal invertor of the foot
- Adductus and supinates the foot
Tibilalis posterior tendon - arterial supply
Arterial supply from the posterior tibial, peroneal and sural
- Has a watershed area around the medial malleoli
Function of tibialis posterior tendon
- Stabilise lower leg
- Facilitates foot inversion
- Supports the foot’s medial arch
- Plays a critical role in hindfoot inversion during the gait cycle
Presenting symptoms/signs of tibialis posterior insufficiency
- Post-malleolar pain
- Arch pain + aching
- Progressive flat foot deformity
- Forefoot problems: progressive hallux valgus, metatarsalgia, lesser toe deformities
- Rarely, tarsal tunnel syndrome
How might tibialis posterior insufficiency typically present
- Valgus hindfoot
- Acquired flatfoot
- forefoot abduction
How might tibialis posterior insufficiency occur
- 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
What is the most common cause of adult acquired flat foot
- Tibialis posterior insufficiency
Causes of tibialis posterior insufficiency
- Trauma
- Chronic flat foot
- Inflammatory arthropathy
- Degenerative tendonopathy
Two main groups affected by tibialis posterior insufficiency
- younger patients aged 30-40 with inflammatory arthropathy
- Older, typically female patients 50-60 years old with degenerative tears
Tibialis posterior insufficiency - complaints
- Post-malleolar pain
- Arch pain + aching
- Progressive flat foot
- Forefoot problems: progressive hallux valgus, metatarsalgia, lesser toe deformities
- Rarely, tarsal tunnel syndrome
Tibialis posterior insufficiency - examination
- 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
Single foot tiptoe test
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
Tibialis posterior insufficiency - treatment (non-surgical)
- Analgesics
- Shore wear modification
- Orthortics - medial arch supports
- Physiotherapy
Tibialis posterior insufficiency treatment (surgery)
- Reconstruction (tendon transfer)
- Fusion(if secondary arthritis)
Surgical approach to tibialis posterior tendon
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
Dangers of surgery on tibialis posterior tendon
- Saphenous nerve and the tibialis posterior tendon are particularly vulnerable
