Orthopaedic Features of an Insensate Patient
- Familial dysautonomia (Riley-Day, HSAN III) is autosomal recessive, predominantly Ashkenazi Jewish (ELP1/IKBKAP), and combines autonomic dysfunction with markedly reduced pain and temperature sensation.
- The orthopaedic problems follow from the insensate state and are shared with the other congenitally insensate conditions (congenital insensitivity to pain, the HSANs, Lesch-Nyhan).
- About 90 percent of surviving children develop a spinal curve, in the first decade, characteristically kyphotic.
- Management is prevention: early diagnosis, protection and patient/parent education. Fractures may be treated conservatively; progressive scoliosis, osteomyelitis, septic arthritis and Charcot joints need operative treatment.
- Autonomic instability makes anaesthesia and surgery higher-risk, and the absence of pain does not mean the absence of injury or infection.
- “Familial dysautonomia (Riley-Day, HSAN III) = autosomal recessive (Ashkenazi Jewish; ELP1/IKBKAP); autonomic dysfunction + reduced PAIN/TEMPERATURE sensation → INSENSATE orthopaedic problems.
- “The insensate cluster (shared with CIPA/other HSANs): Charcot (neuropathic) joints, PAINLESS/unrecognised fractures, osteomyelitis/septic arthritis, self-mutilation/auto-amputation.
- “The spine is near-universal: ~90% of survivors develop a curve in the FIRST DECADE, characteristically KYPHOTIC. Bracing is minimally successful. Posterior fusion achieves only ~25% correction (friable osteoporotic bone), avoid anterior transthoracic approaches (pulmonary) - but pneumonia frequency fell and ataxia improved after surgery.
- “Management = early diagnosis + PROTECTION + patient/family EDUCATION to prevent complications; conservative fractures; OPERATE for progressive scoliosis, deep infection, Charcot instability. Beware autonomic instability perioperatively; absence of pain != absence of injury.
Overview and the Insensate Footprint
What it is. Familial dysautonomia (Riley-Day syndrome) is hereditary sensory and autonomic neuropathy type III (HSAN III), an autosomal-recessive disorder that occurs predominantly in Ashkenazi Jewish individuals and is caused by mutation of ELP1 (formerly IKBKAP). It combines autonomic dysfunction with markedly reduced pain and temperature sensation.
Why it reaches an orthopaedic clinic. The protective function of pain is lost. The patient does not feel or normally avoid damaging stimuli, so injuries go unrecognised and untreated, and the clinician's vigilance must replace it. It is the same mechanism that produces neuropathic orthopaedic problems across the congenitally insensate conditions: congenital insensitivity to pain, the other HSANs and Lesch-Nyhan syndrome.
The insensate cluster. In congenitally insensate patients, Riley-Day included, the abnormal pain response drives a recognisable set of orthopaedic problems:
- Fractures, often painless and unrecognised
- Charcot (neuropathic) joints, from repeated unperceived trauma to insensate joints
- Osteomyelitis and septic arthritis, with ulcers and deep infection developing without the usual pain warning
- Scoliosis, common and progressive
- Dislocation
- Self-mutilation and auto-amputation
The principle. Management is prevention: early diagnosis, protection, and education of the patient and family to watch for unrecognised injury and infection, because the absence of pain does not mean the absence of damage. Protection means protective footwear and orthoses, joint protection and avoidance of falls and injury. Fractures can often be treated conservatively, whereas progressive scoliosis, deep infection and Charcot instability require operative treatment.
Surgery carries its own risk. The autonomic dysfunction makes anaesthesia and surgery higher-risk, so any orthopaedic procedure needs careful multidisciplinary perioperative planning. The individual risks are set out in the next section.
ELP1 Biology, Diagnosis and Perioperative Risk
The gene. ELP1 on chromosome 9 encodes a scaffold subunit of the Elongator complex, which works in transcriptional elongation and tRNA modification. A near-universal founder splice-site mutation, IVS20+6T to C, causes tissue-specific skipping of exon 20. ELP1 is reduced especially in the nervous system, so sensory and autonomic neurons fail to develop and survive.
The population. The founder mutation accounts for more than 99.5% of Ashkenazi patients, and the Ashkenazi carrier frequency is about 1 in 32. Carrier screening and prenatal diagnosis are therefore available.
Diagnosis. Classically the child is of Ashkenazi ancestry and shows these hallmarks; genetic testing for ELP1 is now confirmatory:
- Alacrima: no overflow tears when crying
- Absent fungiform papillae: a smooth tongue
- Absent or depressed deep-tendon reflexes, which go early
- No axon flare after intradermal histamine
Why surgery is high-risk. The systemic features of the disease are what raise perioperative risk:
- Dysautonomic crises: cyclical vomiting, hypertension, tachycardia and sweating, treated with benzodiazepines or clonidine
- Orthostatic hypotension with supine hypertension, from baroreflex failure, which swings the pressure both ways
- Impaired thermoregulation, with intraoperative temperature lability
- Recurrent aspiration and restrictive lung disease from oropharyngeal incoordination, especially important before scoliosis surgery
COTAWhy Anaesthesia Is High-Risk - COTA
Hook:COTA: Crises, Orthostatic lability, Thermoregulation, Aspiration - plan any orthopaedic anaesthetic around the autonomic system.
The Spine
The expected course. About 90 percent of surviving children with familial dysautonomia develop a spinal curvature, appearing in the first decade of life, so spinal deformity is the rule rather than a complication to watch for. The curve is characteristically kyphotic rather than lordotic, and a kyphoscoliosis is the expected pattern. A child with this diagnosis should be under spinal surveillance from early childhood rather than referred when a curve is noticed.
The series behind the numbers. In an Israeli series, 51 of the 90 nationally reported cases attended a scoliosis clinic, and 37 of them had an increased thoracic kyphosis alongside the scoliosis.
Bracing. Orthotic treatment and physiotherapy were minimally successful at best, and a brace is poorly tolerated. In an insensate child the brace breaks down skin silently, and chest compression worsens the restrictive lung disease.
Fusion. Thirteen of the 51 patients underwent posterior spinal fusion, the indication being curve progression. The operation is high-risk because of the restrictive and aspiration lung disease, intraoperative autonomic lability, and poor nutrition and wound healing, and complications exceeded those of ordinary paediatric deformity surgery.
- Only about 25 percent correction was obtained in the majority, and no more should be expected, partly because friable, osteoporotic bone would not tolerate the corrective force
- Anterior transthoracic approaches were avoided despite the kyphosis, because of the frequency of pulmonary complications
- Bank bone alone was used, to spare the patient the trauma of graft harvest
What fusion gives back. After fusion the series reported a marked fall in the frequency of pneumonia and an improvement in ataxia, the latter for reasons the authors could not explain, with an obvious gain in quality of life. The operation should therefore not be presented to a family purely as a high-risk attempt to straighten a spine. Modest radiographic correction coexisted with a real respiratory and functional benefit, which is the honest way to frame the consent conversation.
The spinal deformity is managed on the principles of neuromuscular scoliosis, and because the curve appears in the first decade it also falls under early-onset scoliosis.
The Insensate Fracture and Charcot Joint
The fracture. Because the patient feels no pain, they continue to load the injured limb, risking delayed union or malunion and progression to Charcot collapse. Immobilisation must therefore be prolonged and enforced, since the patient will not self-limit. Casts and orthoses must be well moulded and the skin checked vigilantly, because pressure sores form silently on insensate skin.
The neuropathic joint. The surgical goal is a stable, plantigrade, braceable limb, by realignment or arthrodesis, rather than anatomical perfection. Painless superimposed infection must always be excluded.
The insensate joint is the same process described in Charcot neuroarthropathy, and the other hereditary neuropathy that reaches an orthopaedic clinic with a deformed foot is Charcot-Marie-Tooth disease.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A child with familial dysautonomia presents with a swollen, deformed but painless ankle and a previously unrecognised fracture. How do you think about and manage this?”
What it is
- Familial dysautonomia (Riley-Day, HSAN III); autosomal recessive
- Predominantly Ashkenazi Jewish; ELP1/IKBKAP gene
- Autonomic dysfunction + reduced pain/temperature sensation
Orthopaedic cluster (insensate)
- Charcot (neuropathic) joints; painless/unrecognised fractures
- Spinal curvature in ~90 percent, first decade, kyphotic; bracing minimally successful
- Fusion: ~25 percent correction (friable bone), avoid anterior transthoracic - but pneumonia fell and ataxia improved
- Osteomyelitis/septic arthritis; dislocation; self-mutilation/auto-amputation
Management
- Early diagnosis + protection (footwear/orthoses/joint protection) + patient/family education
- Conservative fracture care where possible
- Operate for progressive scoliosis, deep infection, Charcot instability; beware autonomic instability perioperatively
Evidence & Key Studies
Orthopaedic manifestations in congenitally insensate patients (incl. Riley-Day syndrome)
- In congenitally insensate patients (including congenital insensitivity to pain, Riley-Day syndrome and Lesch-Nyhan syndrome), an abnormality of pain interpretation/avoidance leads to self-inflicted damage.
- The orthopaedic problems and complications included fracture, self-mutilation, auto-amputation, osteomyelitis, septic arthritis, Charcot joints, scoliosis and dislocation.
- Effective management consists of early diagnosis and patient/parent education to prevent complications; fractures may be treated conservatively, progressive scoliosis requires operative intervention, and osteomyelitis, septic arthritis and Charcot joints require appropriate operative treatment.
Aspects of spinal deformity in familial dysautonomia (Riley-Day syndrome)
- About 90 percent of surviving children with familial dysautonomia develop a spinal curvature, appearing in the first decade and usually kyphotic rather than lordotic. Of the 90 cases reported in Israel, 51 attended the scoliosis clinic; 37 had an increased thoracic kyphosis in addition to the scoliosis. Orthotic treatment and physiotherapy were minimally successful at best.
- Thirteen of the 51 underwent surgery, the indication being curve progression, with six years of follow-up. Only posterior fusions were performed - anterior transthoracic procedures were avoided despite the kyphosis because of the frequency of pulmonary complications - and bank bone alone was used to avoid the additional trauma of graft harvest.
- Only about 25 percent correction was achieved in the majority, partly because friable osteoporotic bone limited the corrective force that could be applied, and the complication rate exceeded that of ordinary paediatric deformity surgery. After surgery there was a marked decrease in the frequency of pneumonia and an improvement in ataxia, for reasons the authors could not explain. This is a small retrospective single-country series from the era of Harrington and sublaminar-wire instrumentation, so the technical findings do not transfer directly to modern pedicle-screw constructs.
Tissue-specific expression of a splicing mutation in the IKBKAP gene causes familial dysautonomia
- Identified the major FD mutation: a single base change (T to C) at base pair 6 of the donor splice site of intron 20 of IKBKAP (now ELP1) on 9q31 - the founder mutation carried by the great majority of FD alleles.
- The mutation causes TISSUE-SPECIFIC skipping of exon 20, predominantly in the brain, with reduced IKAP protein expressed in FD brain - the molecular basis of the selective sensory and autonomic neuronal failure while other tissues are relatively spared.
- Penetrance-based incidence in the Ashkenazi Jewish population was estimated at 1 in 32 live births in the families studied, supporting targeted carrier screening.
Familial dysautonomia carrier screening in the Ashkenazi Jewish population
- Screening of 2,518 anonymous Ashkenazi Jewish individuals from the New York metropolitan area gave a carrier frequency for the IKBKAP IVS20(+6T to C) splice-site mutation of 1 in 32 (3.2%, 95% CI 2.5-3.9%).
- That measured frequency closely matched the 3.3% previously ESTIMATED from disease incidence - an independent confirmation rather than a restatement.
- The splice-site mutation accounts for more than 99.5% of known Ashkenazi patients with familial dysautonomia, and haplotype analysis is consistent with a common founder.
- NO carrier of the second mutation, R696P, was found in 2,518 people, placing it below 1 in 2,500 in this population.
- A single PCR with allele-specific oligonucleotide hybridisation detects both mutations, which is what made population carrier screening practical.
The cluster of orthopaedic problems in congenitally insensate patients including Riley-Day syndrome (fracture, self-mutilation, auto-amputation, osteomyelitis, septic arthritis, Charcot joints, scoliosis, dislocation) and the management principles (early diagnosis and patient/parent education to prevent complications; conservative fracture treatment; operative treatment for progressive scoliosis and for osteomyelitis/septic arthritis/Charcot joints) come from the cited Guidera study. The nature of familial dysautonomia (HSAN III, autosomal recessive, Ashkenazi Jewish, ELP1/IKBKAP, autonomic dysfunction with reduced pain/temperature sensation) and the perioperative autonomic-instability risk are standard, well-established teaching. The spinal figures - the 90 percent curvature rate, the kyphotic pattern, the poor response to bracing, the roughly 25 percent correction achieved and the post-operative reduction in pneumonia - come from the Kaplan series, which is small, retrospective, and from the era of Harrington and sublaminar-wire instrumentation, so its technical findings should not be read across to modern constructs. The founder splice mutation (IVS20+6T>C), its nervous-system-restricted exon 20 skipping, and the measured 1-in-32 Ashkenazi carrier frequency come from the cited Slaugenhaupt and Dong studies. No trial compares any treatment strategy in this disease, no curve threshold for surgery has been validated, and no screening interval for the spine or for neuropathic joints has been established, so none is quoted here.