My name is Tom Novacheck. I'm a pediatric orthopedic surgeon at Gillette children's specialty healthcare in St. Paul Minnesota. I'm associate medical director at the hospital and professor of orthopedics at the university of Minnesota.
Cerebral palsy affects gait first and foremost because remember cerebral is a neurological condition and as such, it affects the brain. And we know that the brain is the main controller of movement and walking, in addition to those primary neurological problems, there are secondary effects in the musculoskeletal system where the muscles and the bones and joints may not grow and develop properly. And as a result, muscles and joints can be tight. Uh, bones can be out of alignment and all of those factors can work together to adversely affect cerebral palsy gait with the advent of clinical instrumented gait analysis, we have a better understanding of the gait patterns and particularly with unilateral or hemiplegic cerebral palsy gauge. And these are known as, types 1, 2, 3, and four, in order of, increasing severity. The mildest forms affect only the ankle, for instance, with the muscles that pull the foot up and they can have a foot drop and swing phase. And in stance, the heel can come up early and there can be what's called equinus or toe walking. More severe starts to affect the knee. And those problems can affect the hamstrings and the rectus femoris and lead to either crouch gait or stiffness of the knee and swing phase. And finally, in the most severe forms, the hip is also affected. And in cases, there can be poor hip extension or the hip can be held across the midline in what's called abduction with unilateral cerebral palsy.
The neurological condition really dictates the gait pattern and it tends not to progress over time. So if you have a problem only at your ankle, when you're born, you tend to only have a problem at your ankle throughout lifetime. Joint subluxation is quite uncommon for children who walk well with cerebral palsy. So if we think about the GMFCS rating system and people who walk independently, GMFCS one and two, joint subluxations are really uncommon with one big exception and that's type four hemiplegic cerebral palsy. They are at a significant risk, in the way to detect joint subluxations is with routine x-ray screening.