Foot Muscle Forces & Deformities - Foot & Ankle

Introduction

Simple Deformities
Deformity	Strong Muscle	Weak Muscle
Equinus	Gastroc-soleus complex	Dorsiflexors
Cavus	Plantar fascia, intrinsics	Dorsiflexors
Varus	Posterior tib, anteiror tib	Peroneal brevis
Supination	Anterior tibialis	Peroneus longus
Flatfoot	Peroneus brevis	Posterior tibial tendon

Complex Deformities
Deformity	Strong Muscle	Weak Muscle
Equinovarus + supination	Gastroc-soleus complex, posterior tibialis, anterior tibialis	Peroneus brevis & longus
Equinovalgus	Gastroc-soleus complex, peroneals	Posterior tibialis, anterior tibialis
Calcaneovalgus	Foot dorsiflexors/evertors (L4 and L5)	Plantar flexors /inverters (S1 and S2)

Introduction
- Equinovarus foot
  - most common deformity following stroke
    
    use AFO and physical therapy for at least 6 months to await for possible neuro recovery
    
    overactivity of the tibialis anterior, with contributions from the FHL, FDL, and tibialis posterior
  - treatment
    
    nonoperative
    
    AFO fitting
    
    physical therapy
    
    Phenol or botox injections
    
    surgical
    
    split anterior tibial tendon transfer (SPLATT)
    
    flexor hallucis longus tendon transfer to the dorsum of the foot and release of the flexor digitorum longus and brevis tendons at the base of each toe
    
    gastrocnemius or achilles lengthening
- Foot drop
  - Inability to dorsiflex at the ankle and/or toes
  - Commonly result from peroneal nerve palsy
    
    Multiple etiologies
    
    central nervous system (brain, spinal cord, nerve roots)
    
    peripheral nervous system (sciatic nerve, peroneal nerve)
    
    traumatic (knee dislocation, laceration, blunt trauma)
    
    compressive (compressive mass, deformity correction)
    
    systemic (diabetic polyneuropathy, mononeuropathy)
    
    Iatrogenic (laceration, casting, positioning, surgical injury)
    
    Mechanical (muscle debridement, tumor excision, etc.)
  - Presentation - variable depending on location of nerve injury
    
    Motor
    
    Loss of ankle/toe dorsiflexion (DPN)
    
    Loss of ankle eversion (SPN)
    
    Sensory
    
    Loss of first dorsal webspace sensation (DPN)
    
    Loss of lateral leg/dorsal foot sensation (SPN)
  - Treatment
    
    Nonoperative
    
    Observation
    
    AFO bracing
    
    Therapy - stretching and supple joints
    
    Operative
    
    Acute injury
    
    Laceration - repair, grafting, or nerve transfer
    
    Chronic injury
    
    Tendon transfer
    
    Posterior tibial tendon transfer to lateral cuneiform +/- gastroc or Achilles tendon lengthening

Physical Exam
- Silfverskiöld test
  - improved ankle dorsiflexion with knee flexed = gastrocnemius tightness
  - equivalent ankle dorsiflexion with knee flexion and extension= achilles tightness

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T