4 a adult acquired flat foot - derek park
TRANSCRIPT
Adult Acquired Flatfoot
Introduction
• Low arched foot is variable in population• Flatfoot – abnormal loss of arch with pain
Causes• Posterior Tibial Tendon Dysfunction (PTT)• Achilles/Gastroc contracture – 2º PTT dysfunction• Inflammatory arthritis• 1º midfoot arthritis of fracture non-union• Calcaneus or Cuboid fracture malunion• Peroneal Muscle spasm• Neuropathic deformity• Coronal plane angulation
Deformity• Flatfoot is the end point of an medial collapsed arch.• Hindfoot → Valgus• Forefoot → Supinates• Sagittal Plane → longitudinal arch collapses• Axial Plane → Forefoot abducts• Lateral column is shortened• 3D – dorsolateral peritalar subluxation
Deformity
Arches of the foot
• Medial Longitudinal Arch• Lesser Longitudinal Arch• Transverse Arch
Arch Supports
• Static– Spring ligament– Superficial deltoid– Plantar fascia
• Dynamic– PTT– Ext/In toe flexors– Achilles
PTT during Gait
• Heel contact – shock absorber• Midstance – initiates inversion of the hindfoot• Propulsive phase – Vector of Achilles shifts
medially secures hindfoot
Clinically
• Foot Pain (medial, lateral), Knee, Hip• Swelling – medial along PTT• Standing, walking aggravate• Abnormal gait (push off)• Progressive flat foot
Physical Examination • Visualise legs from knee down - Arch height
compared with other side, too many toes sign• Look at heel alignment• Palpate along PTT• Single heel raise• Test Inversion/Eversion • Gastroc-soleus – Contractures• Subtalar joint for mobilty• Fixed vs Rigid
RADIOGRAPHS
Lateral Xray
Lateral talar-1st MT (Meary angle),>4º Flatfoot
17-32° is normal
Talo navicular coverage angle
> 7 degrees indicates lateral subluxation
AP
Look for talar aligment
Other Imaging
• USS – stage 1 of PTT dysfunction correlates well with surgical findings
• MRI – More detailed
PTT - Anatomy
• Posterior Tibia → 1º Navicular Tub, 2º 2-4 MT, Cuniforms, Cuboid
• Also attaches to deep fasica, peroneal tendons and long and short flexors
• Avascular zone in tendon behind medial malleolus
Staging
Treatment
• Aim – pain free and normal biomechanics• Depend on underlying condition • Stage of disease
TREATMENT• Non-operative: Tibialis posterior eccentric
strengthening exercises, NSAIDs, orthotics
• Operative: depending on stage of disease
• Early stages with no fixed deformity = orthotics & tendon transfer and heel osteotomy
• Later stages with fixed deformity = triple fusion or pantalar fusion
Non-operative
• Anti-inflammatory to control pain• Rest in a short leg cast• Bracing and orthotics
– Flexible, Medial supports, AFO, UCBL– Rigid, accommodative devices, custom moulded
AFO
Surgical Principles
• If PTT is source of pain should be addressed with repair and augmentation
• Pain from osseous impingement, arch alignment must be improved to decompress painful area
• Arthritis pain – joint fusion• Consider TA lengthening
Stage 1 PTT dysfunction
• Repair and augment tendon • Consider calcaneal sliding osteotomy• Medial Approach • Diseased tendon maybe excised• FHL/FDL/PB is as an augment
Collapsed Arch, no degeneration
• Aim is to realign the hind foot without sacrificing the hind foot joints
• Augment PTT • Medial Calcaneal osteotomy• Medial column stabilisation• Lateral column lengthening
EARLY STAGES
Medial column stabilisation
• Medial Collapse at met-cun, NC joint• Collapse can be seen on lateral films• Realignment can result in good correction of
the arch• Often combined with calcaneal osteotomy
Lateral column lengthening
• Hindfoot valgus drive the calcaneus posteriorly
• Lengthening drives the foot around the talus through the TNJ
• Osteotomy of ant process of calcaneus or through the cal-cub joint
Lateral column lengthening
• Improves talar head coverage, reduces forefoot abduction, diminishes hindfoot valgus
• Peroneal lever arm is lengthened, planter fascia is lengthened, TA shifts medially
Forefoot Supination
• Collapse of hindfoot leads to compensatory forefoot supination
• Elevated first ray after hindfoot correction• First metatarsocuneiform planter flexion
arthrodesis
Advanced Flatfoot (Stage 3)
• Triple arthrodesis is gold standard for rigid flatfoot (Subtalar, TN, CC)
• Performed with realignment• Address the forefoot supination
Ankle Valgus (Stage 4)
• Pantalar fusion • 2 stage procedure
– Triple fusion– Ankle replacement