Scoliosis, Hip Dysplasia & Perioperative Risk
- PRADER-WILLI SYNDROME is a genetic IMPRINTING disorder caused by loss of the PATERNALLY expressed genes at chromosome 15q11-q13 (paternal microdeletion, maternal uniparental disomy, or an imprinting defect), producing neonatal HYPOTONIA and feeding difficulty that evolve into childhood HYPERPHAGIA and OBESITY, with short stature, hypogonadism, developmental delay and behavioural problems.
- The two principal ORTHOPAEDIC manifestations are SCOLIOSIS and DEVELOPMENTAL HIP DYSPLASIA, both driven substantially by the underlying HYPOTONIA; according to PubMed, in a large series scoliosis occurred in about 44% (mostly mild) and hip dysplasia in about 38%, so both are common and must be actively sought.
- SCOLIOSIS in PWS is variable, can present early (the median onset was around 4.5 years, with peaks in early childhood and adolescence) and progresses with growth; its management interacts with GROWTH-HORMONE (rhGH) therapy (widely used in PWS for body composition/stature), so the spine should be MONITORED during rhGH treatment rather than treatment being reflexively withheld.
- DEVELOPMENTAL HIP DYSPLASIA is common (median detection around 1.8 years in one series) and related to hypotonia; it is screened for and managed along standard DDH lines (with awareness that outcomes/treatment uptake can be affected by the syndrome).
- PERIOPERATIVE RISK is a central orthopaedic concern: OBESITY, obstructive SLEEP APNOEA, hypotonia (and respiratory muscle weakness), altered temperature regulation and pain perception, and behavioural difficulties all increase ANAESTHETIC and respiratory risk - so any surgery, especially scoliosis correction, needs careful multidisciplinary perioperative planning.
- MANAGEMENT is EARLY DIAGNOSIS and SURVEILLANCE within a multidisciplinary team: monitor the SPINE (clinical/radiographic, especially during growth and rhGH therapy) and the HIPS, treat scoliosis on its merits (bracing/surgery for progression, with the perioperative caveats) and DDH along standard lines, and optimise the systemic issues (weight, OSA) before any operation.
- “Prader-Willi = imprinting disorder (loss of PATERNAL 15q11-q13); hypotonia -> hyperphagia/obesity, short stature, hypogonadism, developmental delay.
- “Orthopaedic footprint: SCOLIOSIS (~40%, often mild, monitor during growth/rhGH) + DEVELOPMENTAL HIP DYSPLASIA (~30-40%) - both driven by HYPOTONIA.
- “Growth-hormone therapy interacts with scoliosis -> MONITOR the spine (don't reflexively withhold rhGH). PERIOPERATIVE risk = obesity + OSA + hypotonia (anaesthetic/respiratory) - plan carefully, especially for spine surgery.
Scoliosis (~40%) and developmental hip dysplasia (~30-40%), both driven by hypotonia. Monitor the spine during growth and growth-hormone therapy.
Obesity + obstructive sleep apnoea + hypotonia (+ altered temperature/pain) raise anaesthetic and respiratory risk - optimise and plan carefully, especially for scoliosis surgery.
Orthopaedic Manifestations & Perioperative Care
Prader-Willi syndrome is an imprinting disorder (loss of paternal 15q11-q13) with hypotonia, hyperphagia/obesity, short stature and developmental delay. Its orthopaedic footprint is scoliosis (common, often mild, presenting from early childhood and progressing with growth) and developmental hip dysplasia (common), both driven by hypotonia. Scoliosis management interacts with growth-hormone therapy, so the spine is monitored during rhGH rather than treatment withheld reflexively. The major surgical concern is perioperative risk - obesity, obstructive sleep apnoea, hypotonia/respiratory weakness, altered temperature/pain responses and behavioural issues - which must be optimised and planned for, especially before scoliosis correction.
- Surveillance: monitor the spine (clinically/radiographically, especially during growth and rhGH) and the hips (DDH screening/management).
- Scoliosis: treat on its merits (observation/bracing/surgery for progression) - monitor, don't reflexively stop rhGH.
- DDH: manage along standard lines, with awareness of the syndrome.
- Perioperative: optimise weight and OSA, plan anaesthesia/respiratory care; multidisciplinary (endocrine, respiratory, anaesthesia) involvement for any operation.
For the orthopaedic surgeon, the two messages in Prader-Willi syndrome are that the spine and hips need active surveillance, and that the perioperative period is genuinely high-risk. Scoliosis and developmental hip dysplasia are both common and are driven by the underlying hypotonia, so they should be actively sought and monitored, particularly during growth spurts and growth-hormone therapy; the interaction between rhGH and scoliosis means the spine should be monitored during treatment rather than rhGH being reflexively withheld. When surgery is required - especially scoliosis correction - obesity, obstructive sleep apnoea, hypotonia with respiratory muscle weakness, and altered temperature and pain responses combine to raise anaesthetic and respiratory risk, and behavioural issues can complicate care; so weight and OSA should be optimised preoperatively and the operation planned with endocrinology, respiratory medicine and anaesthesia in a multidisciplinary team, with close postoperative respiratory monitoring.
Evidence & Key Studies
Orthopedic manifestations in children with Prader-Willi syndrome
- In 175 children with Prader-Willi syndrome, scoliosis occurred in 43.7% (mostly mild) and hip dysplasia in 38.2%, confirming both as common orthopaedic problems.
- Scoliosis presented at a median age of about 4.5 years with rapidly increasing prevalence around age 5 and in adolescence, and the mean Cobb angle increased with age; hip dysplasia was detected at a median of about 1.8 years.
- Early diagnosis and treatment are important for prognosis, and the onset ages/developmental trends of the different skeletal deformities differ - supporting age-targeted surveillance.
According to PubMed, the high prevalence of scoliosis (about 44%, mostly mild) and hip dysplasia (about 38%) in children with Prader-Willi syndrome, the early/age-dependent onset of scoliosis (median ~4.5 years, peaks around 5 and in adolescence) and hip dysplasia (median ~1.8 years), and the importance of early diagnosis/age-targeted surveillance come from the cited Miao series. The imprinting genetics (loss of paternal 15q11-q13), the role of hypotonia, the interaction of scoliosis with growth-hormone therapy, and the perioperative risks (obesity, OSA, hypotonia) are standard, well-established teaching. (See also our Scoliosis, Developmental Dysplasia of the Hip and Neuromuscular Scoliosis topics.)
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“What are the orthopaedic issues in a child with Prader-Willi syndrome, and what would you be cautious about before operating?”
Mnemonics & Memory Aids
PWS
Hook:PWS: Paternal 15q loss/hyPotonia, Weight+OSA (anaesthetic risk), Scoliosis + hip dysplasia (Surveil, monitor spine on rhGH).
What it is
- Imprinting disorder: loss of paternal genes at 15q11-q13
- Neonatal hypotonia -> hyperphagia/obesity, short stature, hypogonadism, developmental delay
- Hypotonia drives the orthopaedic deformities
Orthopaedic manifestations
- Scoliosis (~44%, often mild) - early onset, progresses with growth
- Developmental hip dysplasia (~38%)
- Interaction with growth-hormone therapy (monitor the spine)
Perioperative risk
- Obesity + obstructive sleep apnoea + hypotonia/respiratory weakness
- Altered temperature regulation and pain perception; behavioural issues
- Optimise weight/OSA; multidisciplinary planning; close postoperative respiratory monitoring