Orthopedic Challenges in PWS: Why Spine Issues Occur

PWS is characterized by severe hypotonia (low muscle tone) in infancy, which gradually improves but never fully normalizes. This muscle weakness means the spine doesn’t have typical muscular support, making children with PWS prone to developing scoliosis, an abnormal curvature of the spine. In fact, scoliosis is present in a large proportion of children with PWS – studies indicate anywhere from about 30% up to 70% or more of patients may develop scoliosis. The curvature often starts early in life (some PWS infants and toddlers show signs of scoliosis by age 2-4) and can progress during rapid growth phases like adolescence. Low muscle tone allows the spine to bend sideways more easily, and if a child with PWS is also overweight (common in PWS due to hyperphagia), the added weight can strain the spine further. Besides scoliosis, kyphosis (forward rounding of the upper back) can appear in later childhood or adulthood. Ligamentous laxity (loose ligaments) in PWS may contribute to abnormal spinal alignment as well. Another factor is the use of growth hormone therapy – many children with PWS receive growth hormone to improve height, muscle mass, and metabolism. There has been some debate about whether growth hormone might trigger or worsen scoliosis. Fortunately, research shows that the incidence of scoliosis in PWS is not significantly increased by growth hormone use. This is reassuring for families using this important therapy, though regular spine monitoring remains critical. Overall, the combination of hypotonia, body composition, and other PWS-related factors creates a “perfect storm” for spinal curvature problems. Families and primary care providers should be aware of this risk so that regular spine check-ups (at least annually) are part of the care plan.

Scoliosis in PWS: Early Detection & Monitoring

Scoliosis (a sideways curvature of the spine) is a major concern for patients with PWS, so proactive monitoring is essential. Because scoliosis can develop very early in PWS, pediatricians and parents should be on the lookout even in infancy and toddler years. Many experts recommend a systematic spine examination at least once a year for children with PWS. In practical terms, this means checking your child’s back for any asymmetry: is one shoulder higher, one shoulder blade more prominent, or does the spine look curved? If any doubt exists, a referral to a pediatric orthopedic specialist for a detailed evaluation is warranted. Early detection is important because mild curves are easier to manage and can often be treated with less invasive methods. According to data from a large study, the median age when scoliosis is first noted in PWS was around 4.5 years. Two peak periods for scoliosis progression in PWS are early childhood (around 5 years old) and adolescence during the pubertal growth spurt. Knowing this, our clinic emphasizes close observation during these high-risk windows. If a curve is detected, the orthopedic team will likely obtain standing spine X-rays (to measure the Cobb angle, which quantifies the curve). For very young children (infants/toddlers) who can’t easily get X-rays, a physical exam or ultrasound might be used to assess the spine until they’re a bit older. Families should also watch for signs like an unusual sitting posture or leaning to one side – since PWS children often have delayed motor milestones, subtle changes in posture during sitting or walking can be clues. It’s important to note that scoliosis in PWS isn’t just a cosmetic or orthopedic issue; it can impact respiratory function. Because children with PWS may already have breathing weaknesses (due to hypotonia and sometimes obesity), a significant spinal curve can restrict lung expansion. Indeed, severe kyphoscoliosis in PWS has been linked to respiratory failure and cor pulmonale (strain on the heart from lung issues). This underlines why timely care of spinal issues is critical – a well-aligned spine contributes to better breathing and overall health for a child with PWS

Treatment Approaches for Spinal Curvature

When it comes to treating scoliosis in PWS, the approach is highly individualized, taking into account the child’s age, the severity of the curve, and their overall health status. Conservative (non-surgical) management is the first line for most children, especially younger ones. For instance, if a toddler or preschooler with PWS has a moderate curve (say 20–30 degrees), our specialists may recommend serial casting. In this technique, performed under anesthesia, we gently manipulate the child’s spine towards straighter alignment and apply a specialized cast from shoulders to hips. The cast holds the spine in a corrected position, and over 2–4 months the child’s growth can help “remold” the spine. Casts are changed periodically (every 2–4 months) as the child grows. This method has shown encouraging results – about one in three young PWS patients in one series had their scoliosis significantly improve with casting, allowing them to transition to a brace thereafter. The goal is to guide the spine’s growth and delay or even avoid surgery while the child is very small. After casting, or for milder curves, bracing is commonly used. A thoracolumbar sacral orthosis (TLSO), which is a custom-molded plastic brace, can be worn typically 16–20 hours a day to hold the spine and prevent further curvature. In PWS, bracing is often started after a period of casting or if a curve is caught early. Families sometimes worry that bracing could be uncomfortable or interfere with daily life, but modern braces are fairly lightweight, and kids can do most activities in them. It’s important to make bracing fun – we often decorate braces with child-friendly designs and stress that wearing the brace is a team effort to “make my back strong.” For older children or more severe scoliosis (curves exceeding ~40–50°), surgery may become necessary. Surgical correction typically involves spinal fusion, where the surgeon straightens the spine and fuses the vertebrae in place with rods and screws. However, children with PWS require extremely careful surgical planning and specialized expertise. Patient selection for surgery is critical – the surgeon, anesthesiologist, and the family must weigh the benefits (a straighter spine, better sitting balance, potentially improved breathing) against the risks. PWS patients have a higher risk of surgical complications than typical scoliosis patients. Some reported complications include difficulties with wound healing, higher chance of spine bone fusion not healing properly (pseudoarthrosis), or even rare neurological issues. Furthermore, PWS children often have increased skin picking behaviors and a high pain threshold, which can affect recovery and wound care. At our pediatric orthopedic center, we mitigate these risks by meticulous pre-operative preparation (including nutrition and respiratory optimization), and engaging a multidisciplinary team for aftercare (such as endocrinologists for hormonal support and pulmonologists for breathing support). In certain cases, newer surgical techniques can be considered: for example, expandable growing rods for younger children (to allow the spine to keep growing after surgery), or vertebral body tethering (VBT) which is a fusionless surgery that preserves motion (though VBT is typically reserved for idiopathic scoliosis and requires careful consideration in PWS due to hypotonia). The bottom line is that if surgery is indicated, having it done at a center familiar with rare diseases like PWS and neuromuscular scoliosis is crucial for safety and success. The encouraging news is that with the right approach, many children with PWS who undergo scoliosis treatment (whether casting, bracing, or surgery) do very well. Families often report that after treatment, their children sit straighter, have improved endurance, and in some cases improved lung function because the spine is better aligned. Successful outcomes are most likely when problems are caught early and managed by an experienced team.

Beyond the Spine: Other Orthopedic Issues in PWS

While spine issues are a major focus, PWS can affect other parts of the musculoskeletal system too. Another common issue is hip dysplasia – an instability or shallow development of the hip joint. Due to low muscle tone, some infants with PWS are born with hip dysplasia or even dislocations. About 30–40% of children with PWS show evidence of hip dysplasia on exams or X-rays. The good news is that serious hip deformities requiring surgery are relatively uncommon, occurring in maybe 5% of patients (around 1 in 20 children with PWS). Often, if a PWS baby has mild hip dysplasia, we may adopt a conservative approach (like soft bracing) and monitor it, because interestingly, adults with PWS do not seem to suffer the typical arthritis from residual hip dysplasia that others would. However, any infant with PWS should have hip screening and, if needed, treatment early – usually with methods like a Pavlik harness or casting if the hip is dislocated. Flat feet (pes planus) are also frequently seen in PWS. Low muscle tone leads to less support of the arches, so many toddlers with PWS develop very flat, flexible feet. Without intervention, they could grow into adults with foot pain due to misalignment. Our clinic’s approach is to use custom orthotic inserts or small braces (UCBL orthoses) in early childhood to shape the foot’s arch and heel alignment. These are usually worn during the day inside shoes. By providing proper foot alignment while a child is growing, we help them develop a more typical arch and improve their walking efficiency. Most kids with PWS tolerate these inserts well, especially if we start them when the child is first learning to walk, as it just becomes a normal part of their routine. Another aspect to be aware of is osteoporosis and fractures. Children and adolescents with PWS have an increased risk of low bone density. Contributing factors include reduced muscle forces on bones, less mobility in some cases, and nutritional differences. Some studies report that up to 20–30% of kids with PWS have had fractures due to osteopenia (brittle bones). Parents should ensure their child has adequate calcium and vitamin D, and endocrinologists sometimes check bone density in PWS patients, especially if there’s a history of fractures. Weight-bearing activities (supervised exercise, walking) can strengthen bones, and newer treatments like bisphosphonates have been used in severe cases to improve bone density. Preventing fractures also circles back to treating scoliosis – a very twisted spine can itself be at risk for vertebral fractures. Whole-child care means we address nutrition, bone health, and physical therapy in conjunction with any orthopedic treatments.

Compassionate, Specialized Care Leads to Success

Caring for a child with PWS requires a team approach, and families should feel that they are not alone on this journey. At our pediatric orthopedic practice, we work closely with geneticists, endocrinologists, nutritionists, pulmonologists, and therapists to support every aspect of the child’s health. We understand that parents of children with PWS often face additional stressors – concerns about their child’s future, questions about surgical risks, and juggling multiple therapies. Our role is not only to provide surgical and medical expertise but also to offer guidance, support, and empathy. For example, if a brace is needed for scoliosis, we take the time to explain to both parent and child why it’s important and how it will help them do the things they love, like playing or sitting comfortably in class. Because PWS is a rare disease, many local providers may have limited experience in its orthopedic management. We frequently provide second opinions for families – perhaps your local doctor has recommended a spine surgery and you feel unsure, or you want to confirm the best course of action for a hip problem. Seeking a second opinion at a specialized center is a wise step; we can often either reassure you that the plan is sound or suggest alternative approaches tailored to PWS. We also welcome families traveling from other regions or even countries (“medical tourism”) when specialized care is not available near home. Our practice is accustomed to coordinating with out-of-town families to make the process as smooth as possible, recognizing the extra effort it takes for you to come to us for expert care. In summary, Prader-Willi Syndrome comes with significant orthopedic challenges, especially involving the spine, but there is hope and help available. Through vigilant monitoring, early interventions like casting and bracing, and judicious use of surgery in the right cases, children with PWS can maintain better alignment and function. We have seen children with PWS go from struggling to sit due to a severe scoliosis, to post-treatment sitting upright with a big smile and engaging more with their world. Every child with PWS is unique, and our commitment is to provide compassionate, individualized care that maximizes their health and abilities. With careful patient selection for any procedure and a focus on safety, we strive for successful outcomes that improve quality of life. Families can take comfort in knowing that with specialized pediatric orthopedic support, many PWS-related orthopedic issues can be managed effectively – allowing your child to focus on being a child, growing, learning, and enjoying life to the fullest extent possible.

For a comprehensive evaluation and to explore your treatment options, don’t hesitate to schedule an appointment or seek a second opinion consultation with Dr. Arun Hariharan at Paley Orthopedic & Spine Institute by calling (561) 602-9155.

What Are Skeletal Dysplasias?

Skeletal dysplasias are a category of genetic conditions that cause abnormal bone and cartilage development. There are hundreds of types (over 400 identified), each with its own genetic cause and pattern of bone involvement. They are rare, occurring in roughly 1 in every 4,000–5,000 births. What these conditions have in common is that they often result in disproportionate short stature – meaning the limbs or trunk are shorter than typical relative to the overall body size. For example, the most common skeletal dysplasia, achondroplasia, causes short arms and legs with a relatively average-sized torso and head. Other types, such as diastrophic dysplasia, spondyloepiphyseal dysplasia (SED), or metaphyseal dysplasias, have different specific features, but all involve the bones not forming or growing normally. Because these conditions affect the skeletal system during development, children’s bones respond differently to injury or treatment than adult bones would. For instance, a gentle guiding of growth or a minor surgical correction can sometimes yield big improvements in a child, since their bones are still growing and malleable. Early diagnosis is important. In some cases, skeletal dysplasia can be suspected even before birth via ultrasound (especially the severe forms that present with very short limbs or other bone differences in utero). However, milder dysplasias might not be obvious until infancy or toddlerhood, when parents notice things like a child’s short stature or bowing of the legs. A definitive diagnosis usually involves genetic testing. Once the specific type of dysplasia is identified, it helps guide the management plan and lets the medical team anticipate what orthopedic challenges might arise.

Common Orthopedic Challenges in Skeletal Dysplasia

Children with skeletal dysplasias can face a variety of orthopedic issues due to the way their bones form. Some of the common challenges include:

Limb Deformities: It’s very common to see bowed legs or knock-knees in certain dysplasias. For instance, in achondroplasia, the legs often develop a bow-legged alignment (genu varum) once the child starts walking, due to the thigh and shin bones’ growth patterns. This can make walking clumsier and, if severe, can cause knee or ankle pain. Some dysplasias also cause arm deformities, like curved forearms. In addition, joint alignment issues such as clubfoot can be present in conditions like diastrophic dysplasia or arthrogryposis. Early on, these deformities might be mild, but as the child grows and weight-bearing increases, they can worsen.

Spine Problems: Scoliosis (sideways curvature of the spine) or kyphosis (forward rounding) can occur in many skeletal dysplasias. For example, achondroplasia infants often have a noticeable kyphosis in the lower back (lumbar kyphosis) when sitting, which usually improves once they start walking. However, as adults, achondroplasia patients are at risk for spinal canal narrowing (spinal stenosis) in the lower back, which can pinch nerves. Other dysplasias like SED are known for early-onset scoliosis. In a severe dysplasia, the rib cage might be small, which combined with spine curvature can cause breathing difficulties. Roughly 50–60% of children with certain dysplasias (like SED or OI) might develop a significant spinal curve.

Joint Laxity or Rigidity: Some conditions cause overly flexible joints (as in some forms of collagen disorders), while others cause stiff joints. Both situations can lead to orthopedic issues. Ligamentous laxity (loose ligaments) can contribute to things like hip instability or early arthritis in joints because the joints aren’t held in alignment. On the flip side, conditions that cause joint contractures or stiffness might limit a child’s range of motion.

Neurological Considerations: Since bones can develop abnormally, sometimes the spaces in the skull or spine that nerves pass through are smaller.
Achondroplasia, for example, is associated with a risk of craniocervical junction compression (the opening at the base of the skull can be narrow, pressing on the upper spinal cord). This isn’t an orthopedic issue per se, but it is something our team screens for alongside neurosurgeons. Also, spinal stenosis in the lower back, as mentioned, can compress spinal nerves and cause pain or numbness, typically in adolescence or adulthood for achondroplasia.

Fractures and Bone Strength: In conditions like osteogenesis imperfecta (OI), which is technically a type of skeletal dysplasia (characterized by brittle bones), fractures are a major problem. In other dysplasias, bones may not be brittle, but they can be mis-shapen and that alone can predispose to fractures if the mechanics are off.

It’s worth noting that not every child with a skeletal dysplasia will have all these issues. The manifestations are quite variable. For example, one child with achondroplasia might have significant leg bowing and need surgery, while another might have straighter legs and never require an operation. A child with a milder dysplasia might just have short stature with relatively minor orthopedic concerns. Part of our role is to anticipate which problems are most likely for your child’s specific condition and to keep a watchful eye as they grow.

Treatment and Management Strategies

There is no cure for skeletal dysplasia in the sense of making the bones grow normally; management focuses on treating the specific orthopedic issues and maximizing the child’s function. The treatment plan is highly individualized, taking into account the type of dysplasia, the severity of bone changes, and the child’s age and developmental status. Here are key management strategies:

Observation and Guided Development: In mild cases or in very young children, sometimes the best “treatment” is careful observation and letting the child grow a bit before intervening. For example, with mild bowlegs in a toddler with achondroplasia, we may simply monitor for a while; some alignment may improve once they have been walking longer or if their muscle strength increases. During this period, we focus on developmental therapies – physical therapy to encourage muscle strengthening and motor skills. Because children’s bones are growing, timing is everything. Intervening too early or too late could reduce the effectiveness. We often talk about “guided growth” for certain deformities: one such technique is temporary hemiepiphysiodesis, where we implant a tiny device or screw on one side of a growth plate around the knee to slow that side down, allowing the other side to catch up and gradually straightening a leg over time. This is typically done for moderate bowlegs or knock-knees around ages 4–10, while the child still has substantial growth remaining. It’s a less invasive strategy that uses the child’s growth to fix the deformity, rather than an immediate osteotomy (bone cut).

Physical Therapy and Bracing: Many children with skeletal dysplasia will benefit from physical therapy (PT) to improve muscle strength, coordination, and range of motion. Stronger muscles can sometimes compensate for bony differences and protect joints. For instance, core strengthening can help stabilize a mildly scoliotic spine or delay progression. Bracing is another conservative tool. In younger children with early scoliosis, a custom back brace might slow the curve’s progression. In a child with knee hyperextension or instability, a knee-ankle-foot orthosis (KAFO) brace might help with walking. For infants with certain deformities like clubfoot (which can appear in some dysplasias), we use casting and bracing (the Ponseti method) to correct the foot shape gradually. Braces don’t “cure” the underlying bone issue, but they can provide support and prevent things from getting worse, buying time until a child is older or until a surgical solution is appropriate.

Surgical Interventions: Surgery can address many of the orthopedic complications of skeletal dysplasia, and advances have made these surgeries safer and more effective. Some of the surgical treatments include:

Osteotomy: This literally means cutting the bone. We do osteotomies to correct a bone that has grown crooked. For example, a child with severe bowing of the tibias (shin bones) might undergo osteotomies to realign them straight. The bones are then held in the correct position with plates and screws or rods while they heal. The result is straighter legs which improve gait and reduce joint stress. In our practice, we often plan osteotomies when the deformity is causing functional issues (e.g., difficulty walking, frequent falls, pain) and when the child is at an age where healing is rapid (often between 4–6 years for first corrections, though it depends on severity).

Spinal Surgery: If a child has a significant spinal curvature (scoliosis > 40–50° or a severe kyphosis) that is worsening, surgical correction may be recommended. In skeletal dysplasias, spine surgery can be tricky due to small bones and any existing spinal canal narrowing. However, techniques like growing rods (for young children) or definitive spinal fusion (for older children/teens) are utilized. Spinal fusion surgery involves attaching metal rods and screws to the spine and grafting bone to fuse the vertebrae together, which corrects and stabilizes the curve. According to pediatric guidelines, if a curve is progressive and above roughly 45°, and the child is of sufficient age (often around 8–10 or older for fusion; younger kids might get growing rods first), surgery is considered to stop further progression. We counsel families that bracing is generally not effective once a curve is very large in these conditions.

Limb Lengthening: One question that arises in skeletal dysplasia is whether to do limb lengthening procedures. Limb lengthening can be done to increase height or correct leg-length discrepancies. For short stature conditions, lengthening both legs (and sometimes arms) can gain significant height, but it is an extensive process requiring multiple surgeries and long rehabilitation. The decision to pursue limb lengthening is very personal and depends on the specific condition and family goals. Some families opt to do it during later childhood or adolescence to help a child achieve greater adult height, which can assist with daily activities (like reaching counters, etc.) and self-esteem. Modern techniques involve devices like external fixators or internal magnetic lengthening rods that slowly pull bones apart, allowing new bone to fill in. Each surgery might add a few inches of length. We emphasize careful patient selection here: not every child is a candidate, and the child’s psychological readiness is as important as their physical readiness because of the long process.

Spinal Canal Decompression: In cases like achondroplasia, if the spinal cord or nerves are compressed, we work with neurosurgery to do decompression surgeries. For example, a lumbar laminectomy (removing part of the vertebra to open the canal) can relieve symptoms of spinal stenosis if a teenager or adult with achondroplasia develops leg pain or numbness. Similarly, decompression at the craniocervical junction might be needed in infancy if there’s dangerous compression in that area (often that is picked up on screening MRI).

Multidisciplinary Care: Managing skeletal dysplasia isn’t just about “fixing bones.” It requires a team. Orthopedic management goes hand in hand with care from other specialists. For instance, our clinic’s team will coordinate with:

Geneticists – to confirm diagnoses and advise on any new therapies.
Endocrinologists – sometimes involved in growth hormone therapy or metabolic aspects in certain dysplasias.
Neurosurgeons – for spine and brainstem evaluations.
Pulmonologists – if small chest size or spine deformity affect breathing.
Physiotherapists and Occupational Therapists – for rehab and maximizing developmental skills.
Social Work and Patient Support Groups – connecting families with support networks.
This comprehensive approach ensures that the child’s overall well-being is addressed, not just the isolated orthopedic issue. It can feel overwhelming to have so many specialists, but our experience is that coordinated care leads to the best outcomes.
Emphasizing Rare Expertise and Family-Centered Care

Because skeletal dysplasias are uncommon, finding a medical team with experience in these conditions can make a huge difference. Our pediatric orthopedic practice has specialized clinics for skeletal dysplasia, where surgeons, nurses, and therapists who are familiar with these disorders come together. We believe that careful planning and timing of interventions lead to successful outcomes. For example, operating too early on a bow leg might result in recurrence as the child grows; operating too late might cause unnecessary joint damage in the interim. Through our experience, we create an individualized roadmap for each patient – mapping out potential surgeries not all at once, but spread out at optimal ages. We always discuss with families what to expect in the long term.

Optimism for the Future

Despite the complex medical care, children with skeletal dysplasias frequently surprise and inspire us with their resilience. With modern orthopedic treatments, many can run, play, and engage in activities alongside their peers. It’s heartwarming to see a child who once struggled with mobility due to severe bowlegs, later riding a bike or dancing – all because their legs were corrected and strengthened with therapy. Ongoing research is improving the outlook even more. In conclusion, skeletal dysplasia requires specialized and compassionate orthopedic management, but families are not alone in this journey. By understanding the common issues and the array of treatments, parents can approach each decision with confidence. Our pediatric orthopedic team’s philosophy is to treat not just the bone problem, but the whole child – empowering them to reach their potential. With expert care and a loving, tailored approach, they can defy limits and lead active, fulfilling lives.

For a comprehensive evaluation and to explore your treatment options, don’t hesitate to schedule an appointment or seek a second opinion consultation with Dr. Arun Hariharan at Paley Orthopedic & Spine Institute by calling (561) 602-9155.