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Orthopedic Challenges in Prader‑Willi Syndrome [2020 CONFERENCE VIDEO]

Dr. Van Bosse has practiced pediatric orthopedic surgery for 27 years, helping hundreds with PWS. In this video, he discusses some treatment options.

In this 60‑minute workshop, Dr. Van Bosse discusses the diagnosis and treatment of orthopedic challenges in PWS and how in his practice of pediatric orthopedic surgery since 1994, he has helped hundreds of patients with PWS. The session includes Q&A from participants in the 2020 FPWR Virtual Conference and those new parents to the FPWR community who are interested in PWS diagnosis and treatment.

Click below to watch the video. If you're short on time, scroll down for timestamps to find the portions you're most interested in.


Presentation Summary With Timestamps

0:30 Sarah Peden introduces Dr. Van Bosse

  • Dr. Harold Van Bosse has been practicing orthopedic pediatric surgery exclusively since 1994.
  • His interest in treating patients with PWS developed from treating a two‑year‑old PWS patient with severe scoliosis. He has treated the very youngest children with PWS and spine deformities.

1:10 Dr. Van Bosse presents

  • Prader‑Willi Syndrome is the most common genetic obesity disorder.
  • The first case was described in 1887, with an adolescent girl who presented in this way.
  • In 1956 Prader, Labhard and Willi described a series of patients with certain physical characteristics.
  • 25 years later in 1981, Ledbetter, Riccardi, and Airhart identified the microdeletions of chromosome 15 in the patients that led to the syndrome presentation.

1:53 How Prader‑Willi Syndrome’s Genetics look 

  • It happens in Chromosome 15
  • If the microdeletion lacks from the father’s chromosome leg, it’s Prader‑Willi Syndrome and if it’s missing from the mother’s chromosome leg, it’s called Angelmann Syndrome.
  • There are three variants of the syndrome’s genetic presentation: Deletion, Material Uniparental Disomy, or Methylation Defect.
  • Since it is a genetic syndrome, it’s unlikely that it “runs in the family”, and most causes of PWS run <1% risk.

3:20 The Characteristics of Patients with Prader‑Willi Syndrome

  • Babies are born with hypotonia, some of them could have hypogonadism, strabismus, born with short stature, small hands and feet, and an obsessive interest in food and/or obesity from the ages of 1 to 6 years old.
  • Some of the older children display learning disabilities, and some behavioral problems such as temper tantrums, stubbornness, controlling and manipulative behaviors, and obsessive‑compulsive characteristics.
  • PWS is very rare: it occurs about 1:10,000 to 1:30,000 births.
  • ‘Why doesn't my Orthopaedist know about PWS?’ Treatment needs to be specific, can’t be generalized from other syndromes or genetic conditions.

4:40 Orthopaedic and Rehab Issues in PWS

  • Developmental delay (milestones)
    • Hypotonia is recognized early on, during the prenatal and delivery periods. There is decreased fetal movement in the womb and they’re often born via Cesarean section.
    • In the newborn period, they have a weak cry and have a poor sucking ability.
    • Infants and toddlers will initially have poor head control and poor postural control while sitting.
    • Their milestones can take twice as long as an average infant, with motor delays in 90‑100% of patients with PWS. Sitting is accomplished at an average of 12 months of age, and walking at an average of 27 months of age.
    • In the physical exams, the trunk will especially show an abnormally low tone compared to the arms and legs, while their hands and feet will appear small, their genitals underdeveloped. 
    • All these delays seem to improve with Growth Hormone treatments.
    • Recommended treatment can start off with early intervention while focusing on balance and motor abilities as soon as possible, and then occasionally going into bracing.
    • Bracing is a key focus for therapy treatment, and in order to increase their ankle‑foot control, Dr. Van Bosse will often prescribe Ankle Foot Orthosis (AFO) in order to promote a stable foundation for walking, so that they can get walking any way possible and explore their surroundings.
  • Joint laxity/flatfoot
    • Hypotonicity or low tone of the feet will often lead to flat feet or “Pes Planus”, which is very common in children with PWS.
    • About 41% of PWS parents will mention flat feet, which is due to the laxity of the ligaments and musculature. 
    • Children will often “fall” into pronation, and their arch slides down. 
    • There is a less strong foot functioning when walking and running.
    • The residual effects are poor balance, wide standing and walking base, leg fatigue, spine or postural compensation.
    • Dr. Van Bosse favors a brace for this characteristic, called a UCBL, which repositions the heels while it pushes the outer border of the foot.
    • Another commonly favored brace is a super malleolar orthosis, which holds the foot a bit above the ankle level.
    • These treatments help in overall alignment and on getting the stance 
  • Osteopenia (low bone calcium) leads to frequent fractures
    • Osteoporosis refers to low bone mineral density.
    • There are different studies that show different rates in the PWS population, depending on the population's age. Up to 29% of PWS patients in Britain and 45% in Philadelphia seem to have had fractures, which they weren’t able to recognize at the time because PWS patients have a higher pain threshold.
    • DEXA scans usually show a 20% lower bone mass density (BMD), especially in the areas of the lumbar spine, pelvis, and lower extremities.
    • Recommended treatments are growth hormone, vitamin D and calcium, lots of activity so that their bones get strengthened, and to be aware of any limping or favoring an arm, as well as orthopedic surgical planning, since their bones won’t have the same mineral density if there is surgery that involves bone.
  • Hip dysplasia
    • The third most common orthopedic issue in PWS patients after developmental delay (#3) and spine deformities (#2).
    • Dysplasia is abnormal development or growth. It is presumably normal during early development, but the deformity is caused as it grows through late pregnancy or after birth, but because they aren’t very active children, there isn’t a ton of movement and stimulation in the joint.
    • Hip dysplasia can lead to hip arthritis in adults.
    • Few hip dislocations in PWS, and some of them happen as early as birth.
    • The incidence of hip dysplasia is 8‑30%, and its prevention includes an early screening of hips (when they start sitting independently), activity, and stimulation, as well as continuing to screen every 1‑2 years for at-risk hips.
    • He recommends activity and movement as the most important and natural treatment option in order to help PWS children develop their hip bones properly.
  • Spine deformities
    • Scoliosis is any side‑to‑side curve seen from behind.
    • Kyphosis or Lordosis are other types of deformities that exaggerate the upper or lower spine seen from the side.
    • There is a prevalence among PWS patients of 60‑70%, especially at two age points: 23% of children before their 4th birthday, and adolescents.
    • Scoliosis curves of 20 to 25 are recommended to be observed only, while those that go above 50 will progress in adulthood. 40 to 50 is a gray zone, where surgery is indicated, but he mentions he will delay surgery until a curve is over 50.
    • Hidden spine deformities in babies and children are common. 
    • There are no differences in BMI between children with or without scoliosis. If there is obesity, more than 50% of all curves start before obesity.
    • Females have around a 10% higher chance of developing scoliosis than males, but both genders have an equal risk of curve progression. Uniparental Disomy seems to have a slightly higher risk of developing scoliosis.
    • About 15% of PWS children will need spine surgery. 
    • There is a cardiopulmonary compromise when there is an exaggerated spine deformity because their lungs have less space and therefore don’t get enough oxygen into the bloodstream for their bodies. Over time, the heart will have to work overtime. 

27:40 Treatment Options

  • Although it’s difficult to draw conclusions and there are few reported operative cases in the literature, Dr. Van Bosse recommends the following treatment options:
    • The first step is Screening: Once a child starts sitting, it’s important to have yearly screenings/radiographs to set a starting point in time of the shape of their spine while sitting.
  • Physical Therapy should start from the get‑go:
    • Trunk strengthening, sensory integration, and keeping the young PWS child laying down while they develop their normal gross motor skills is key so their extremities can develop before their trunk.
    • Hippotherapy, or horse therapy, can help them use different parts of their back muscles to keep upright while horseback riding. It encourages the child’s body to exercise and stay in alignment. It’s ideal for children who need head, trunk, and leg control, and therapists can provide extra support and resistance while they ride.
    • The Therasuit Method uses soft proprioceptive orthotic devices to restore alignment and proper function of postural muscles. They also allow children to relearn proper motor patterns for functional movement.     
  • Casting should start before patients reach 3 years of age. It is still effective with 5, or even up to 7‑year‑old children, but it can be expanded only up to five years after it’s been placed. This procedure is done under anesthesia and changed every so often depending on their age. After a specific goal is reached—normally this means the curve is small enough that spontaneous curve progression is likely halted—or it plateaus, post‑treatment can include bracing. 
    • The average age at first cast was 32 months, the average number of casts is 8, and the average follow-up is 57 months.
  • Bracing is recommended for large curves (20‑25), to correct the curve and prevent its progression.
    • Each case is unique and can progress differently, and as Dr. Van Bosse reviews specific cases, he reminds us that it is very hard to predict if the curve will progress or if it will be corrected.
  • Some cases might need surgery.
    • Surgery is indicated for curves between 40 and 50 degrees, at maturity.
    • Scoliosis, or side‑to‑side curves, and kyphosis/lordosis, or front‑to‑back alignment can both be treated with surgery.
    • There’s a high rate of potential complications in PWS, including infections due to skin picking, anesthetic issues (intra- or perioperative), as well as pulmonary or respiratory difficulties during the procedure due to apnea.
    • Non‑fusion spinal instrumentation allows the spine to grow naturally to its adult size while maintaining alignment.
    • Another type is the MAGEC Rods System, which stands for MAGnetic Expansion Control, which allows for the use of an electromagnet that can expand the rods in the clinic from outside of their spine without having to go through surgery.
    • Spinal fusion surgery is for curves over 50 at maturity.
    • It is beneficial to start growth hormone therapy once scoliosis is diagnosed, in order to prevent the curve progression.

52:30 Q&AFPWR Enewsletter

Topics: Research

Susan Hedstrom


Susan Hedstrom is the Executive Director for the Foundation for Prader-Willi Research. Passionate about finding treatments for PWS, Susan joined FPWR in 2009 shortly after her son, Jayden, was diagnosed with Prader-Willi Syndrome. Rather than accepting PWS as it has been defined, Susan has chosen to work with a team of pro-active and tireless individuals to accelerate PWS research in order to change the future of PWS. Inspired by her first FPWR conference and the team of researchers that were working to find answers for the syndrome, she joined the FPWR team in 2010 and led the development of the One SMALL Step walk program. Under Susan’s leadership, over $15 million has been raised for PWS related research.