The lower extremity in Morquio syndrome

Department of Orthopaedics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA.
Journal of pediatric orthopedics (Impact Factor: 1.43). 07/2012; 32(5):534-40. DOI: 10.1097/BPO.0b013e318259fe57
Source: PubMed

ABSTRACT The modalities and results of surgical intervention in the lower extremity in children with Morquio syndrome type A [mucopolysaccharidosis-IV (MPS-IVA)] have not been well described. The aims of this study are to define the lower extremity deformities, and describe the results of intervention in MPS-IVA patients.
Retrospective chart and radiograph review of 23 MPS-IVA patients with a minimum follow-up of >2 years. Patients were divided into no intervention and surgical groups. Demographic data, surgical details, clinical results, and complications were recorded. Standard lower extremity radiographic measurements made on standing radiographs at initial presentation, preoperatively (in surgical group), and at the final follow-up were used to study the deformities and effects of hip, knee, and ankle surgery. Descriptive statistics were performed.
There were 11 boys and 12 girls. The average age at presentation was 6.8±3.4 years and at the last visit was 13.5±5 years with a mean follow-up of 6.7±3.7 years. Progressive hip subluxation, genu valgum, and ankle valgus were observed in all patients without intervention. Twenty patients had a total of 159 lower extremity surgical procedures (average, 8 procedures per patient). There were 61 hip, 78 knee, and 20 ankle procedures. Surgery resulted in improvement of the center edge angle, femoral head coverage, lateral distal femoral angle, medial proximal tibial angle, tibiofemoral angle, and lateral distal tibial angle. Mechanical axis of the lower extremities improved after intervention. Six patients (12 hips) had recurrence of hip subluxation after acetabular osteotomies and/or femoral varus derotation osteotomy, and 8 patients (16 knees) had postoperative genu valgum recurrence requiring subsequent intervention. There was no recurrent hip subluxation after shelf acetabuloplasty.
Progressive hip subluxation, genu valgum, and ankle valgus were seen and often needed surgery. After shelf acetabuloplasty and varus derotation osteotomy, there was no recurrent hip subluxation. Recurrence after genu valgum correction was common.
Level IV, therapeutic case series.

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    • "(C) Knee valgus in a 7 year-old Morquio A patient. Reproduced from Dhawale et al. [Dhawale et al., 2012] "
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    ABSTRACT: Morquio A syndrome (mucopolysaccharidosis IVA) is a lysosomal storage disorder associated with skeletal and joint abnormalities and significant non-skeletal manifestations including respiratory disease, spinal cord compression, cardiac disease, impaired vision, hearing loss, and dental problems. The clinical presentation, onset, severity and progression rate of clinical manifestations of Morquio A syndrome vary widely between patients. Because of the heterogeneous and progressive nature of the disease, the management of patients with Morquio A syndrome is challenging and requires a multidisciplinary approach, involving an array of specialists. The current paper presents international guidelines for the evaluation, treatment and symptom- based management of Morquio A syndrome. These guidelines were developed during two expert meetings by an international panel of specialists in pediatrics, genetics, orthopedics, pulmonology, cardiology, and anesthesia with extensive experience in managing Morquio A syndrome.
    American Journal of Medical Genetics 01/2015; Part A(9999A):1-15. DOI:10.1002/ajmg.a.36833 · 3.23 Impact Factor
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    • "1A and B). The significantly impacted height in the MorCAP study population (Table 1) reinforces the assertion of the severe skeletal implications of MPS IVA in all clinical phenotypes [5] [6] [11] [17] [34]. These severe skeletal manifestations may impact the accuracy of measuring growth in MPS IVA patients as progressively worsening muscle weakness or bone abnormalities can negatively impact patient ability to be measured in a standing position, thus requiring measurement by length. "
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    ABSTRACT: OBJECTIVES: The objectives of this study are to quantify endurance and respiratory function and better characterize spectrum of symptoms and biochemical abnormalities in mucopolysaccharidosis IVA subjects. METHODS: MorCAP was a multicenter, multinational, cross sectional study amended to be longitudinal in 2011. Each study visit required collection of medical history, clinical assessments, and keratan sulfate (KS) levels. RESULTS: Data from the first visit of 325 subjects (53% female) were available. Mean age was 14.5years. Mean±SD height z-scores were -5.6±3.1 as determined by the CDC growth charts. Mean±SD from the 6-minute-walk-test was 212.6±152.2m, revealing limitations in functional endurance testing, and 30.0±24.0stairs/min for the 3-minute-stair-climb test. Respiratory function showed limitations comparable to MPS VI patients; mean±SD was 1.2±0.9l based on forced vital capacity and 34.8±25.5l/min based on maximum voluntary ventilation. Mean urinary keratan sulfate (uKS) was elevated for all ages, and negatively correlated with age. Higher uKS correlated with greater clinical impairment based on height z-scores, endurance and respiratory function tests. The MPS Health Assessment Questionnaire reveals impairments in mobility and activities of daily living in comparison to an age-matched control population. CONCLUSIONS: MPS IVA is a multisystem disorder with a continuum of clinical presentation. All affected individuals experience significant functional limitations and reduced quality of life. Older patients have more severe exercise and respiratory capacity limitations, and more frequent cardiac pathology illustrating the progressive nature of disease.
    Molecular Genetics and Metabolism 02/2013; 109(1). DOI:10.1016/j.ymgme.2013.01.021 · 2.83 Impact Factor
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    ABSTRACT: The gait in children with Morquio syndrome (MPS IV) has not been previously described. We reviewed the charts, gait analysis reports, and radiographs of nine children with no previous lower extremity surgery. Children with MPS IV had a slower walking speed, reduced cadence, and reduced stride length as compared with normal (P<0.05). There was increased knee flexion, genu valgus, and external tibial torsion during stance (P<0.05). Kinetics showed that knee varus moment was increased (P<0.05). There was a strong correlation between genu valgus measured on gait analysis and standing radiographs (r=0.89).
    Journal of pediatric orthopaedics. Part B / European Paediatric Orthopaedic Society, Pediatric Orthopaedic Society of North America 09/2012; 22(1). DOI:10.1097/BPB.0b013e32835a0e6d · 0.66 Impact Factor
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