Definition
· Viral disease characterized by selective destruction of anterior horn cells in the spinal cord or motor nuclei in the brainstem
· Largely eradicated in developed countries through vaccination but remains present in underdeveloped regions
· Postpolio syndrome (PPS) refers to the delayed onset of new neuromuscular symptoms in survivors of acute poliomyelitis
· PPS typically develops 30–40 years after the initial infection and represents an aging phenomenon rather than viral reactivation
Anatomy
· Causes permanent loss of lower motor neurons -- muscle denervation and imbalance
· Recovery occurs through collateral sprouting and remaining motor unit hypertrophy
· These units gradually fail with aging – progressive weakness
· Hallmark feature is weakness with preserved sensation
· Triceps surae musculature is commonly affected – gait instability
Evaluation
· Muscle weakness without sensory deficit
· PPS presents with new or progressive weakness, joint pain and fatigue
· Easy fatigability is the most common and disabling symptom
· Symptoms often occur in the limb that was less involved during acute infection
· Physical examination reveals muscle atrophy, contractures, gait abnormalities and decreased functional reserve
Imaging
· Primarily used to assess secondary musculoskeletal deformities
· Radiographs assist in evaluating joint degeneration, malalignment and fixed deformities that may influence surgical planning
Treatment
· Non-surgical
o Exercise performed well below maximal muscle capacity combined with scheduled periods of rest
o Sub-exhaustion strengthening to reduce muscle breakdown
o Patient education regarding lifestyle modification and energy conservation
o Orthoses to improve stability and maintain functional independence
· Surgical
o Reserved for patients whose deformities exceed their functional capacity or cannot be managed with orthoses alone
o Tendon transfers, contracture releases, and arthrodesis to optimize alignment
o Often performed to allow effective bracing
o Avoid overlengthening tendons, particularly Achilles, to prevent calcaneal gait
o Arthrodesis of the ankle, hindfoot, or midfoot is indicated for painful arthritis or instability unresponsive to orthotic treatment
Take Home Messages
· Entrapment neuropathies of the foot and ankle most commonly present with burning pain and paresthesia, while motor deficits are often minimal or absent
· Morton’s neuroma is not a true neuroma but a compressive neuropathy, most frequently affecting the 3rd–4th web space, with symptoms exacerbated by tight shoes and high heels
· Tarsal tunnel syndrome is the most common compression neuropathy of the foot and ankle, typically producing plantar burning pain, a positive Tinel sign, and symptoms aggravated by standing or walking
· Deep peroneal nerve entrapment (anterior tarsal tunnel syndrome) should be suspected in dorsal foot pain with first web space paresthesia, especially when symptoms worsen with plantarflexion or high-heel use
· Most nerve entrapment syndromes respond initially to nonoperative management, including activity modification, shoe wear changes, orthoses, injections, and physical therapy, with surgery reserved for refractory cases
· Acquired spastic equinovarus is the most common foot deformity in adults with upper motor neuron lesions, resulting from muscular imbalance and spasticity, and significantly impairing gait and function
· Poliomyelitis and postpolio syndrome are characterized by motor weakness with preserved sensation, and management focuses on energy conservation, sub-exhaustion exercise, orthotic support, and carefully selected surgical interventions as adjuncts to bracing