Restricted joint range of motion in patients with MPS II: correlation with height, age and functional status

Aim: The aims of the study were to assess shoulder range of motion (ROM) in patients with mucopolysaccharidosis type II (MPS II) and to correlate joint mobility with patients height, age and functional status. Methods: Passive ROM and Z-score of height were followed in 29 patients with MPS II (mean age 11.5 years, range 2-29 years) between the years 2005 and 2010. Passive ROM was measured by a goniometer, and height, by a stadiometer. Functional status was assessed by an age-appropriate health assessment questionnaire (HAQ). Results: (i) A strong correlation was observed between patients' age and Z-score of patients' height (R = 0.78, p < 0.001). (ii) A medium correlation was observed between Z-score of patients' height and passive shoulder flexion and abduction (R = 0.697, p < 0.001 and R = 0.63, p < 0.001, respectively). The progression of restriction was slower in attenuated patients. (iii) Restrictions in shoulder flexion and abduction were already observed before the second year of life. (iv) ROM limitations intensified and became more severe with age. (v) Activities of daily living depended on cognitive impairment of patients with MPS II. Conclusion: Range of motion limitations in patients with MPS II correlate with patients' height, increase with patients' age and are more pronounced in a severe form of MPS II.