Down syndrome in children: the role of the orthopaedic surgeon

Imaging of the craniovertebral junction anomalies in children

The craniovertebral junction (CVJ) is interposed between the unsegmented skull and the segmented spine; it is functionally unique as it allows the complex motion of the head. Because of its unique anatomy, numerous craniometric indices have been devised. Because of its complex embryology, different from that of the adjacent skull and spine, it is commonly the seat of malformations. Because of the mobility of the head, and its relative weight, the craniovertebral junction is vulnerable to trauma. Like the rest of the axial skeleton, it may be affected by many varieties of dysplasia. In addition, the bony craniovertebral junction contains the neural craniovertebral junction and its surrounding CSF: any bony instability or loss of the normal anatomic relationships may therefore compromise the neural axis. In addition, the obstruction of the meningeal spaces at this level can compromise the normal dynamics of the CSF and result in hydrocephalus and/or syringohydromyelia. To image the CVJ, plain X-rays are essentially useless. MR is optimal in depicting the soft tissues (including the neural axis) and the joints, as well as the bone itself. CT still may be important to better demonstrate the bony abnormalities.

Is Apolipoprotein E4 an Important Risk Factor for Dementia in Persons with Down Syndrome?

Down syndrome is one of the most common genetic causes of intellectual disability and is characterized by a number of behavioral as well as cognitive symptoms. Triplication of all or part of human chromosome 21 has been considered as the main cause of Down syndrome. Due to the location of the amyloid precursor protein on chromosome 21, many of the neuropathological features of early-onset Alzheimer's disease including senile plaques and neurofibrillary tangles are also present in Down syndrome patients who are either demented or nondemented. Significant advances in medical treatment have increased longevity in people with Down syndrome resulting in an increased population that may be subjected to many of the same risk factors as those with Alzheimer's disease. It is well established that harboring one or both apolipoprotein E4 alleles greatly increases the risk for Alzheimer's disease. However, whether apolipoprotein E4 contributes to an earlier onset of dementia or increased mortality in Down syndrome patients is still a matter of debate. The purpose of this mini review is to provide an updated assessment on apolipoprotein E4 status and risk potential of developing dementia and mortality associated with Down syndrome.

Total hip arthroplasty in Down syndrome patients: an improvement in quality of life: replacement arthroplasty in Down syndrome (RADS) study group

The purpose this study was to assess survival rates, clinical outcomes, and radiographic outcomes of total hip arthroplasty in Down syndrome patients. We reviewed 26 total hip arthroplasties (21 patients) performed by four experienced hip surgeons. These patients had a mean age of 35 years and a mean follow-up of 106months. Clinical outcomes were assessed using Harris Hip scores, and radiographic evaluation for component fixation and migration was performed. The overall survival with aseptic failure as an endpoint was 85%. The mean Harris Hip score improved to 84 points at final follow-up. While these patients can be challenging to treat, excellent surgical technique and selective use of acetabular constraint can reliably provide patients with excellent pain-relief and improved function.

Posterior occipito-axial fixation applied C2 laminar screws for pediatric atlantoaxial instability caused by Down syndrome: Report of 2 cases

Background

Upper cervical spine instability is one of the most critical orthopedic problems in patients with Down syndrome. However, arthrodesis of the upper cervical spine in these patients can be very difficult to achieve and has a high complication rate because of mental retardation and accompanying various medical conditions of the vital organs. Even now, surgeries in such patients, especially pediatric cases, are challenging and the optimal operative procedure remains unsettled. The purpose of this study was to report 2 cases of pediatric atlantoaxial instability due to Down syndrome in which posterior occipito-axial fixation with C2 laminar screws was performed.

Methods

Case 1 was a girl aged 6 years 10 months who had atlantoaxial rotatory fixation with os odontoideum. Atlantoaxial rotatory fixation was incompletely reduced by halo traction, and it was not maintained without halo-ring and -vest fixation. Posterior occipito-axial fixation with bilateral C2 laminar screws was then performed. Case 2 was a boy aged 10 years 7 months who had atlantoaxial subluxation with os odontoideum. He also had incomplete quadriplegia, so he could neither walk nor have a meal by himself. Posterior occipito-axial fixation with right C2 pedicle and left C2 laminar screws was then carried out.

Results

In case 1 bone union was obtained at 3 months after surgery and the patient's symptoms were resolved. In case 2 bone union was obtained at 3 months after surgery and the paralysis was improved.

Conclusions/level of evidence

In cases of atlantoaxial instability due to Down syndrome, symptomatic patients often present between ages 5 and 15 years and mental retardation interferes with postoperative cervical immobilization. C2 laminar screws can be safely applied for the pediatric axis and biomechanically accomplished rigid fixation. The C2 laminar screw is one of the most useful options to achieve stability of the pediatric atlantoaxial complex without the risk of vertebral artery injuries (level IV case series).

Foot-ground interaction during upright standing in children with Down syndrome

This study aimed to quantitatively characterize the main foot-ground contact parameters during static upright standing and to assess foot evolution with increasing age in young individuals affected by Down syndrome (DS). To this end, 99 children with DS of mean age 9.7 (1.7) were tested using a pressure sensitive mat, and the raw data were processed to extract information about overall and rearfoot, midfoot and forefoot contact area, Arch Index (AI) and average contact pressure. The values obtained were then compared with those calculated from a sample of age- and gender-matched participants (control group, CG). Children with DS exhibited larger midfoot and reduced forefoot contact areas with respect to CG participants (+53% and -35% respectively, p<0.001), increased AI values (DS 0.31, CG 0.20, p<0.001) and increased average contact pressures in the midfoot and forefoot. The overall foot development for the two groups followed a similar trend, although in individuals with DS a curve that relates increases in midfoot contact area with age is characterized by a steeper gradient, and the forefoot contact area appeared systematically smaller regardless of age. The large prevalence of the flatfoot type in children with DS (which is known to be originated by hypotonia and ligamentous laxity) associated with the presence of higher average contact pressure in midfoot and forefoot justify the need for careful podiatric surveillance throughout childhood to reduce balance and gait impairment which are likely to affect untreated subjects when they reach adulthood.

Total hip arthroplasty to treat congenital musculoskeletal abnormalities in the juvenile Down Syndrome hip: review of literature with case

Down Syndrome can result in musculoskeletal abnormalities of the hip at an early age. Avascular necrosis of the femoral head can occur as a result of slipped capital femoral epiphysis causing the patient a great deal of pain, limiting the ability to ambulate. Despite the benefits that this patient group can receive from the surgery, surgeons may be apprehensive to operate. It is our experience that these patients benefit greatly from arthroplasty without complication. In this report, we present a total hip replacement to treat avascular necrosis in an adolescent and address the concerns that surgeons may have in treating this patient population.

Review of cervical spine anomalies in genetic syndromes

STUDY DESIGN

Focused review of the literature.

OBJECTIVE

Assist spine specialists in diagnosis and treatment of cervical spine anomalies found in selected genetic syndromes.

SUMMARY OF BACKGROUND DATA

Cervical spine instability and/or stenosis are potentially debilitating problems in many genetic syndromes. These problems can be overlooked among the other systemic issues more familiar to clinicians and radiologists evaluating these syndromes. It is imperative that spine specialists understand the relevant issues associated with these particular syndromes.

METHODS

The literature was reviewed for cervical spine issues in 10 specific syndromes. The information is presented in the following order: First, the identification and treatment of midcervical kyphosis in Larsen syndrome and diastrophic dysplasia (DD). Next, the upper cervical abnormalities seen in Down syndrome, 22q11.2 Deletion syndrome, pseudoachondroplasia, Morquio syndrome, Goldenhar syndrome, spondyloepiphyseal dysplasia congenita, and Kniest dysplasia. Finally, the chin-on-chest deformity of fibrodysplasia ossificans progressiva.

RESULTS

Midcervical kyphosis in patients with Larsen syndrome and DD needs to be evaluated and imaged often to track deformity progression. Upper cervical spine instability in Down syndrome is most commonly caused by ligamentous laxity at C1 to C2 and occiput-C1 levels. Nearly 100% of patients with 22q11.2 deletion syndrome have cervical spine abnormalities, but few are symptomatic. Patients with pseudoachondroplasia and Morquio syndrome have C1 to C2 instability related to odontoid dysplasia (hypoplasia and os odontoideum). Morquio patients also have soft tissue glycosaminoglycan deposits, which cause stenosis and lead to myelopathy. Severely affected patients with spondyloepiphyseal dysplasia congenita are at high risk of myelopathy because of atlantoaxial instability in addition to underlying stenosis. Kniest syndrome is associated with atlantoaxial instability. Cervical spine anomalies in Goldenhar syndrome are varied and can be severe. Fibrodysplasia ossificans progressiva features severe, deforming heterotopic ossification that can become life-threatening.

CONCLUSION

It is important to be vigilant in the diagnosis and treatment of cervical spine anomalies in patients with genetic syndromes.

Periodontal disease in a patient with Prader-Willi syndrome: a case report

Introduction

Prader-Willi syndrome is a complex genetic disease caused by lack of expression of paternally inherited genes on chromosome 15q11-q13. The prevalence of Prader-Willi syndrome is estimated to be one in 10,000 to 25,000. However, descriptions of the oral and dental phenotype are rare.

Case presentation

We describe the clinical presentation and periodontal findings in a 20-year-old Japanese man with previously diagnosed Prader-Willi syndrome. Clinical and radiographic findings confirmed the diagnosis of periodontitis. The most striking oral findings were anterior open bite, and crowding and attrition of the lower first molars. Periodontal treatment consisted of tooth-brushing instruction and scaling. Home care involved recommended use of adjunctive chlorhexidine gel for tooth brushing twice a week and chlorhexidine mouthwash twice daily. Gingival swelling improved, but further treatment will be required and our patient's oral hygiene remains poor. The present treatment of tooth-brushing instruction and scaling every three weeks therefore only represents a temporary solution.

Conclusions

Rather than being a direct result of genetic defects, periodontal diseases in Prader-Willi syndrome may largely result from a loss of cuspid guidance leading to traumatic occlusion, which in turn leads to the development of periodontal diseases and dental plaque because of poor oral hygiene. These could be avoided by early interventions to improve occlusion and regular follow-up to monitor oral hygiene. This report emphasizes the importance of long-term follow-up of oral health care by dental practitioners, especially pediatric dentists, to prevent periodontal disease and dental caries in patients with Prader-Willi syndrome, who appear to have problems maintaining their own oral health.

Sport participation by physically and cognitively challenged young athletes

Many physically and cognitively challenged athletes participate in organized and recreational sports. Health benefits of sport participation by athletes with disabilities have been well recognized. A careful preparticipation evaluation and proper classification of athletes ensures safe sports participation by athletes with disabilities. Some conditions in these athletes, such as problems with thermoregulation, autonomic control, neurogenic bladder and bowel, latex allergy, and many associated and secondary complications deserve special consideration. This article reviews common medical issues that relate to sport participation by athletes with physical and cognitive disabilities.

Clinical practice. The care of children with Down syndrome

Down syndrome (DS) is one of the most common chromosomal abnormalities. Because of medical advances and improvements in overall medical care, the median survival of individuals with DS has increased considerably. This longer life expectancy requires giving the necessary care to the individual with DS over their total longer lifespan. DS medical guidelines are designed for the optimal care of the child in whom a diagnosis of DS has been confirmed. We present an overview of the most important issues related to children with DS based on the most relevant literature currently available.

Surgical treatment of patellar dislocation in children with Down syndrome: a 3- to 11-year follow-up study

We report results of surgical treatment of ten knees affected by patellar dislocation in six children with Down syndrome. Four knees showed a dislocatable patella (grade III according to Dugdale), two a dislocated reducible patella (grade IV) and four a dislocated irreducible patella (grade V). Symptoms included frequent falls, limping and pain. In all the cases a Roux-Goldthwait-Campbell procedure was performed. Mean age at surgery was 10 years (range 6 years and 6 months to 13 years and 4 months). Patients were reviewed at an average follow-up of 8 years and 8 months (range 3 years and 6 months to 11 years and 5 months). None showed signs of recurrence of the dislocation. The median Lysholm score improved from 57.5 to 91/100. Statistical analysis showed a significant effectiveness of the procedure in improving function, and that surgery was significantly more effective in patients with more severe disability.

Novel subtype of congenital generalized lipodystrophy associated with muscular weakness and cervical spine instability

Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by extreme paucity of adipose tissue from birth, and early onset of metabolic complications related to insulin resistance. Mutations in three genes, 1-acylglycerol 3-phosphate-O-acyltransferase 2 (AGPAT2), Berardinelli Seip Congenital Lipodystrophy 2 (BSCL2), and Caveolin-1 (CAV1) are associated with the three subtypes of this disorder, CGL1, CGL2 and CGL3, respectively. We report two siblings of Hispanic origin who displayed characteristic features of CGL such as generalized loss of subcutaneous fat from birth, acanthosis nigricans, acromegaloid habitus, umbilical prominence, hepatosplenomegaly, hypoleptinemia, dyslipidemia, and insulin resistance. However, no disease causing variants were detected in the DNA sequence of AGPAT2, BSCL2 or CAV1 genes. Further, whole body magnetic resonance imaging (MRI) in the two siblings revealed marked loss of subcutaneous, intraabdominal and intrathoracic fat like in other patients with CGL, but preservation of bone marrow fat which is invariably lost in all patients with CGL1 and CGL2, but not in the patient reported with CGL3. They also had generalized muscle weakness during infancy and early childhood associated with a nearly fivefold increase in serum creatine kinase (CK) levels, but with normal muscle biopsy and electrophysiologic studies. Both patients were also found to have atlantoaxial dislocation requiring surgical intervention. Thus, this pedigree represents a novel subtype of CGL characterized by generalized loss of body fat but with preservation of bone marrow fat, congenital muscular weakness and cervical spine instability. The genetic basis of this novel subtype remains to be determined.

Down syndrome: orthopedic issues

PURPOSE OF REVIEW

The purpose of this review is to update the role of the orthopedic surgeon in the management of Down syndrome as these patients are living longer and participating in sporting activities.

RECENT FINDINGS

Approximately 20% of all patients with Down syndrome experience orthopedic problems. Upper cervical spine instability has the most potential for morbidity and, consequently, requires close monitoring. Other conditions such as scoliosis, hip instability, patellar instability and foot problems can cause disability if left untreated. In some of these conditions, early diagnosis can prevent severe disability.

SUMMARY

Surgical intervention in children with Down syndrome has a high risk of complications, particularly infection and wound healing problems. Careful anesthetic airway management is needed because of the associated risk of cervical spine instability.

Outcomes of medial patellofemoral ligament reconstruction for patellar instability: a systematic review

It has been suggested that in the majority of patellar dislocation cases the medial patellofemoral ligament (MPFL) is disrupted. Accordingly several authors over the past decade have recommended repair or reconstruction of the MPFL to reduce the high incidence of recurrent dislocation. The purpose of this review was to determine whether MPFL reconstruction is a suitable procedure with regards to clinical and radiological outcomes for patients with patellar instability. A literature search using the electronic databases AMED, British Nursing Index, CINAHL, the Cochrane database, EMBASE, ovid Medline, Physiotherapy Evidence Database (PEDro), PsycINFO, Pubmed and Zetoc were performed from their inception to May 2007. All English language, human subject clinical papers reporting outcomes following MPFL reconstruction were included. Eight papers, collectively assessing 186 MPFL reconstructions, were finally included for review. Three reviewers independently assessed the methodological quality of each of the studies using the CASP appraisal tool. When analysed, it would appear that MPFL reconstruction may provide favourable clinical and radiological outcomes for patellar instability patients. However, following a critical appraisal of these papers a number of methodological weaknesses were identified including recruiting small samples, not controlling for confounding variables, and providing limited statistical analysis of results. Future study is recommended to address these methodological flaws, in addition to beginning to assess the effectiveness of this procedure, in different patient groups.