Most of the diseases that seating & mobility professionals see every day — ALS, cerebral palsy, muscular dystrophy, multiple sclerosis — are rare in a mathematical sense relative to the general population. On a more formal level, the National Organization for Rare Disorders (NORD) defines a disease as rare if fewer than 200,000 Americans have been diagnosed with it.
On both levels, that makes arthrogryposis — congenital joint contractures affecting two or more parts of the body, according to NORD — truly rare. Compare, for instance, the prevalence of arthrogryposis — estimates range from one out of 3,000 to one out of 56,000 births, says the U.S. National Library of Medicine — to cerebral palsy, which the Centers for Disease Control (CDC) says affects 1.5 to four births out of 1,000.
But what it lacks in sheer volume of patients, arthrogryposis makes up for in complexity.
For instance, according to AMCsupport.org, an arthrogryposis education, support and advocacy organization, the condition has about 400 different forms, some of which can be traced to a genetic defect — but most cases of arthrogryposis seem to occur randomly.
Arthrogryposis is best known for affecting joints in the upper and lower extremities, but it can impact a number of the body’s other functions. It can affect the central nervous system — the CDC reports that 45 percent of babies born with arthrogryposis die in their first month, often because of central nervous system involvement. Because of their fused joints, babies can suffer fractures during birth. The Freeman Sheldon Syndrome form of arthrogryposis affects muscles in the face. Lacking normal muscle structures in addition to joint contractures, children with arthrogryposis can have difficulty with eating and respiration.
While cognition is not generally impacted, babies with arthrogryposis can be at risk for delayed development in areas such as language acquisition due to their immobility — which makes early intervention crucial.
And here too, arthrogryposis proves its uniqueness by redefining what early intervention can be.
Intervening Before Birth
Theresa Lucas knows first hand about the challenges of the condition. She’s president of Arthrogryposis Multiplex Congenita Support Inc., and also has arthrogryposis herself.
While researchers don’t yet understand everything about how and why conditions for arthrogryposis come about, Lucas says lack of fetal movement in utero seems to be the key.
“Some of the causes are [lack of] movement of the baby,” she notes, “because that’s when joints and your muscles form properly — in the womb, in the amniotic fluid. Sometimes if there’s low fluid and the baby doesn’t move around enough, that can cause the contractures and the muscle issues. The muscle just doesn’t form in the proper way.”
That movement is so critical that when a physician detects arthrogryposis via ultrasound exams, Lucas says the expectant mother may be encouraged to drink coffee or other caffeinated beverages.
“Coffee stimulates the baby to move, and it helps with the muscles,” Lucas says. “So [intervention] can start before birth.”
Another strategy: To deliver the baby early, if its lungs are properly developed, so that arthrogryposis treatments can begin as soon as possible.
Once the baby is born — Lucas says arthrogryposis is often, but not always detected or suspected before birth — healthcare professionals can assess for the level of involvement.
“With every child it would be a little bit different because arthrogryposis affects in so many ways,” she says. “We have some that are so mild that you probably couldn’t tell by looking at them. And then we have the ones that have the [tracheostomy] and the feeding tube and the chair.”
Still, the bigger picture remains the same.
“It varies on how they are affected, but I think the main goal is to get them as independent as possible and to strengthen what they do have,” Lucas says. “The main goal is just to work to be able to get them to do things on their own.”
Seating & Mobility Interventions
The types of seating, positioning and mobility equipment that can help a child with arthrogryposis will vary according to the condition’s severity, Lucas says: “We use walkers, forearm crutches, standers, gait trainers: You name it, we probably use it.”
Jay Doherty, OTR, ATP/SMS, Quantum Rehab regional manager, lists a number of ways that assistive technology can lend support to arthrogryposis patients
“They can have many positioning issues that can impact their everyday life significantly,” he notes. “These contractures can require a significant seat-to-back angle in order to be properly positioned. Their lower extremities may require a custom cushion and very specific positioning components to accommodate for the contractures that may be present in their body.”
Power chair accommodations may also be needed.
“If there are contractures in the upper extremities,” Doherty says, “then they can prevent manual mobility and in some cases prevent the child from driving a power wheelchair with a typical joystick. They may require an alternative control with a custom-mounted position to allow the child to independently control a power wheelchair. The team may need to look at custom mounting of switches as well.”
Lois Brown, MPT, ATP/SMS, recalls working several years ago with an 18-month-old boy severely impacted by arthrogryposis.
“He was carried around, and that was his first real exposure to any kind of mobility,” Brown says. “He had no means of independently moving his body.”
His language acquisition and other developmental milestones were already being delayed due to that lack of mobility, so Brown and the rest of the seating & mobility team wanted to move fast.
The team introduced the boy to a mid-wheel-drive power chair, but discovered a number of challenges related to his arthrogryposis.
“What became the biggest issue with the power chair was that the shortening of the muscles was creating a pretty accentuated lordosis,” Brown says. “Therefore, he was getting a lot of abdominal distention, or abdominal posturing. He was being pulled forward into this excessive anterior pelvic tilt.”
The boy and his clinical team would work on maintaining muscle length and stretching while out of the chair during school-based therapy. But the seating & mobility team also wanted to address the issue via the backrest system.
“We didn’t want to fill the gap caused by the lordosis,” Brown says. “We ended up using a chest strap like you’d use for an adult; we used it in the front, almost across the abdomen, as a key point of control along with the backrest to try to give him the cuing to sit back and make contact with the back.”
The team also added tilt to the seating system.
“Having him sit at 10° or 15° of tilt helped to get his back in contact with the backrest,” Brown explains. “The idea was to cue him and try to get him to make as much weight-bearing contact and lengthening of the muscles as possible.”
Having a physical reminder complemented the stretching activities the boy performed during therapy sessions: “When they stretched him and he had a little give in the muscles, then at least he’d make an eff ort within his range of motion to sit back and make contact with the backrest,” Brown says. “We cued him with a 3″ neoprene chest strap across his abdomen — anterior cuing within the range of motion, to at least use what he had.”
The other major challenge was caused by the boy’s small stature: Significantly shorter statures and lower body weights are common in patients with arthrogryposis, according to The Arthrogryposis Group in Spalding, England.
“We had tremendous difficulty,” Brown remembers, “finding a short enough seat depth and high enough foot support to support his small stature and have him make weight-bearing contact. If you leave your legs hanging down, they pull you more into an anterior tilt. So it’s really important to get the weight-bearing contact, and it took a lot of working with foam blocks and building up the footrest on the power chair to give him that kind of support.”
Anticipating Changes to Come
Working with pediatric clients means anticipating how their needs will change as they grow. That’s no different for kids with arthrogryposis, but this population can also see changes due to other medical interventions.
“Although arthrogryposis is not progressive, often there are multiple surgeries that a child may go through in order to maximize their independence level,” Doherty says. “As a child grows, the seating team will have to overcome many of the same obstacles that need to be overcome by any other child in a seating system; however, some of those issues may seem more challenging due to restrictions in range of motion that are present with the child’s body.”
Casts and splints — to maintain or improve range of motion, Lucas says, and they’re oft en used to correct club foot — are also common interventions, and therefore are factors the seating & mobility team needs to be prepared to address.
“As the casts or splints or surgeries happen, the team needs to accommodate for any changes that are needed in the seating system,” Doherty confirms. “This may require some different needs for a period of time. After those items are discharged or the surgery provides desired changes, the seating system often again needs to be changed.”
In the case of the toddler that Brown worked with, the boy did eventually develop independent mobility on his own: “As his body got a little bit bigger and a little bit stronger, he was able to scoot across the floor on his bottom. He could get out of the chair and at least scoot to be on the floor with his peers.”
But that change, too, caused an issue: Redness on his skin. “They thought it was the wheelchair and the seating,” Brown says, “but it turns out the cause of the abrasions and the redness on his bottom was scooting around on his butt.”
That undesirable side effect of independent mobility brings up another question: Is pain a common problem for people with arthrogryposis?
Experts say the contractures are not initially painful for newborns. Aft er that… it depends, Lucas says.
“I have arthrogryposis, and I don’t have to take any pain medicine,” she says. “I’m not in pain for the most part.” She was diagnosed at age 18 with arthritis — another common condition for arthrogryposis patients — and says that decades later, the arthritis “has settled in some joints, but I don’t take anything major for it. Then again, I know some adults that their pain is tremendous. Again, it varies through each person.”
Anecdotally, Lucas says, “A group of us has realized the ones who have had a lot of surgeries are the ones that have more pain issues.” But she hastens to add that their realization came through conversations rather than formal research.
Envisioning Seating & Mobility Success
The relatively small number of people with arthrogryposis has meant fewer resources devoted to thoroughly researching definitive causes and preventive measures.
And the hundreds of forms of arthrogryposis — though just a handful of types account for most cases — can make treatments, therapies and interventions more challenging.
Still, today’s assistive technology can help to create seating & mobility systems to support and encourage independence.
For instance, once the team was able to create an appropriately sized seating system for the little boy Brown worked with, she says, “He was a perfect driver. The minute I put him in the chair, he intuitively understood how to maneuver himself.”
Likewise, adding tilt to his system as the team did isn’t necessarily common for very young children. But it worked wonders for this particular client.
“He was actually trying to descend a ramp on the playground and he was so fearful,” Brown says. “He didn’t feel that he had postural stability and an ability to react to being thrown off balance. So he was terrified to go down or descend anything.”
Once the team taught the boy how to tilt back before starting down the ramp, “He smiled and came all the way down the ramp and was so proud of himself.”
The team also added a seat elevator “because his stature was so short, he couldn’t reach the computer in the classroom or have access to engage at a level with his peers. That became a big thing.”
And giving children with arthrogryposis the chance to independently move around and explore the world just as their friends do, Lucas says, should be the end goal.
“I heard a doctor once say that with an arthrogryposis baby, the worst they’re going to ever be is the day they’re born,” she says. Lucas adds that she tells new parents of arthrogryposis babies, “They should treat that child just like they would any other child. My mom and dad never raised me any differently than they raised my sister. They didn’t treat me like I had a disability. I had chores and I had rules just like my sister did.
“My mom has always told new parents to let that child lead the way.”