Lonstein and Beck reviewed 464 children with CP to test whether hip dislocation causally drives pelvic obliquity and scoliosis. The study directly challenges the assumed causal triad by analyzing hip status against pelvic obliquity magnitude and laterality across four functional groups. The key question: does the dislocated hip predict the high side of the pelvis, and does greater obliquity mean more dislocated hips?
The prevailing model held that hip dislocation drove pelvic obliquity, which in turn drove scoliosis — a causal triad implying that fixing the hip would protect the spine. This paper tested that model directly in the largest series at the time and found no supporting evidence.
Pelvic obliquity magnitude does not predict hip dislocation rate, and the elevated side of the pelvis does not predict which hip dislocates. All three findings co-occur because they share the same root cause: spasticity and muscle imbalance.
In practice, surgical decisions for hip dislocation, pelvic obliquity, and scoliosis must each stand on their own merits. Correcting a dislocated hip cannot be justified as a strategy to prevent scoliosis progression, and vice versa.
In a child with windswept hips, focus surveillance on the adducted side. That is where dislocation is most likely to occur, independent of which side of the pelvis is elevated.
Lonstein and Beck reviewed 464 children with CP to test whether hip dislocation causally drives pelvic obliquity and scoliosis. The study directly challenges the assumed causal triad by analyzing hip status against pelvic obliquity magnitude and laterality across four functional groups. The key question: does the dislocated hip predict the high side of the pelvis, and does greater obliquity mean more dislocated hips?
The prevailing model held that hip dislocation drove pelvic obliquity, which in turn drove scoliosis — a causal triad implying that fixing the hip would protect the spine. This paper tested that model directly in the largest series at the time and found no supporting evidence.
Pelvic obliquity magnitude does not predict hip dislocation rate, and the elevated side of the pelvis does not predict which hip dislocates. All three findings co-occur because they share the same root cause: spasticity and muscle imbalance.
In practice, surgical decisions for hip dislocation, pelvic obliquity, and scoliosis must each stand on their own merits. Correcting a dislocated hip cannot be justified as a strategy to prevent scoliosis progression, and vice versa.
In a child with windswept hips, focus surveillance on the adducted side. That is where dislocation is most likely to occur, independent of which side of the pelvis is elevated.