they cannot put their heels on the ground. a similar situation can develop if the arms become paralyzed. in some cases the growth of an affected leg is slowed by polio, while the other leg continues to grow normally. the result is that one leg is shorter than the other and the person limps and leans to one side, in turn leading to deformities of the spine (such as scoliosis). osteoporosis and increased likelihood of bone fractures may occur. an intervention to prevent or lessen length disparity can be to perform an epiphysiodesis on the distal femoral and proximal tibial/fibular condyles, so that limb's growth is artificially stunted, and by the time of epiphyseal (growth) plate closure, the legs are more equal in length. alternatively, a person can be fitted with custom-made footwear which corrects the difference in leg lengths. other surgery to re-balance muscular agonist/antagonist imbalances may also be helpful. extended use of braces or wheelchairs may cause compression neuropathy, as well as a loss of proper function of the veins in the legs, due to pooling of blood in paralyzed lower limbs. complications from prolonged immobility involving the lungs, kidneys and heart include pulmonary edema, aspiration pneumonia, urinary tract infections, kidney stones, paralytic ileus, myocarditis and cor pulmonale. post-polio syndrome main article: post-polio syndrome between 25 percent and 50 percent of individuals who have recovered from paralytic polio in childhood can develop additional symptoms decades after recovering from the acute infection, notably new muscle weakness and extreme fatigue. this condition is known as post-polio syndrome (pps) or post-polio sequelae. the symptoms of pps are thought to involve a failure of the oversized motor units created during the recovery phase of the paralytic disease. contributing factors that increase the risk of pps include aging with loss of neuron units, the presence of a permanent residual impairment after recovery from the acute illness, and both overuse and disuse of neurons. pps is a slow, progressive disease, and there is no specific treatment for it. post-polio syndrome is not an infectious process, and persons experiencing the syndrome do not shed poliovirus. orthotics orthosis with stance phase control knee joint paralysis, length differences and deformations of the lower extremities can lead to a hindrance when walking with compensation mechanisms that lead to a severe impairment of the gait pattern. in order to be able to stand and walk safely and to improve the gait pattern, orthotics can be included in the therapy concept. today, modern materials and functional elements enable the orthosis to be specifically adapted to the requirements resulting from the patient's gait. mechanical stance phase control knee joints may secure the knee joint in the early stance phases and release again for knee flexion when the swing phase is initiated. with the help of an orthotic treatment with a stance phase control knee joint, a natural gait pattern can be achieved despite mechanical protection against unwanted knee flexion. in these cases, locked knee joints are often used, which have a good safety function, but do not allow knee flexion when walking during swing phase. with such joints, the knee joint remains mechanically blocked during the swing phase. patients with locked knee joints must swing the leg forward with the knee extended even during the swing phase. this only works if the patient develops compensatory mechanisms, e.g. by raising the body's center of gravity in the swing phase (duchenne limping) or by swinging the orthotic leg to the side (circumduction). epidemiology reported polio cases in 2019' countrywildcasescirculatingvaccine-derivedcases (cvdpv)transmissionstatustype pakistan14722endemicwpv1cvdpv2 afghanistan290endemicwpv1 angola0129cvdpv onlycvdpv2 drc086cvdpv onlycvdpv2 car019cvdpv onlycvdpv2 ghana018cvdpv onlycvdpv2 nigeria018cvdpv onlycvdpv2 philippines015cvdpv onlycvdpv1cvdpv2 ethiopia012cvdpv onlycvdpv2 chad09cvdpv onlycvdpv2 benin08cvdpv onlycvdpv2 togo08cvdpv onlycvdpv2 myanmar06cvdpv onlycvdpv1 somalia03cvdpv onlycvdpv2 malaysia03cvdpv onlycvdpv1 zambia02cvdpv onlycvdpv2 burkina faso01cvdpv onlycvdpv2 china01cvdpv onlycvdpv2 niger01cvdpv onlycvdpv2 yemen03cvdpv onlycvdpv1 total175365 the decade of the last recorded case of paralytic polio. since the creation of this image, nigeria has been certified free of wild polio as of august 2020 and one case was recorded in the us state of new york in july 2022. eradication