Thirty-nine patients with post-poliomyelitic scoliosis and pelvic
obliquity were treated and followed for up to four years. The dominant
pathological mechanism causing the pelvic obliquity was trunk-muscle
imbalance. The natural history of untreated pelvic obliquity is
progression, leading ultimately to dislocation of the hip. The functional
abilities of the patient are then severely restricted. Our aim in treatment
was to obtain the maximum possible correction of pelvic tilt and so to
prevent subluxation of the femoral head. Total correction was obtained in
fifteen patients; no loss of correction was seen in twenty-four patients.
The best results were achieved by preliminary traction, Dwyer
instrumentation distally to the fifth lumbar vertebra, and extensive
posterior fusion extendind distally to the sacrum.