Rehabilitation Of Children And Infants With Osteogenesis Imperfecta.

Lynn H. Gerber, M.D.
Rehabilitation Medicine Department, National Institutes of Health, Bethesda, MD, USA

Rehabilitation Medicine is that specialty which provides evaluation and treatment to promote independence in function. Children with Osteogenesis Imperfecta (OI) often have significant functional limitations. These limitations are a result of a variety of causes, including physical impairments, disease severity and motivational and socioeconomic factors. Linkages between physical impairments and functional limitations are poorly understood, hence risks for disability are not always identified. Additionally, OI is associated with significant disability. Despite a classification system that has provided us with an important framework for identifying phenotypic similarities and differences, the Sillence typology (1) does not provide information about prognosis for function.

Binder, et al (2) in describing needs of infants and children for rehabilitation, have reported a classification system that was developed to assist clinicians in identifying those children with high likelihood of developing significant disability. The groups were differentiated from each other by a variety of physical (anthropomorphic) criteria. These physical properties were then correlated with functional ability of posture control, self-care and mobility. Those with largest heads, shortest trunk and bowed upper extremities were least mobile and frequently fractured their upper extremities. Those with smaller heads, lower head/trunk ratios were able to pull to stand and reached a higher level of independence in self care. Those with the most significant anthropometric abnormalities were also those who had most severe scoliosis and joint laxity. (2)

We have continued to explore relationships between anatomic abnormalities, physical impairments and functional performance. Our studies have shown that long bone bowing of >30 degrees is associated with high fracture risk. (3) Vertebral collapse is commonly seen in this population and is distributed among all the Sillence types. However, looking at preschool age children, (ie <6 yrs.), those with Sillence Type 3 had more severe scoliosis. Analysis of repeated x-rays taken as children aged, failed to support this association in these same children as they grew. (4)

Standard assessments of strength of the lower extremities, correlate with gross motor performance in this population. Hip extensors, abductors, quadriceps and hip flexors had r values of >.5. (5 ) However, the ratio of chest circumference to body length, and an assessment of clinical severity was most predictive. These data further confirm the associations between anthropometric measures and performance of gross motor activities.

Performance, the ability to initiate and sustain physical activity, is a measurable endpoint but is influenced by many factors. We assessed several of these using a variety of self administered questionnaires. Specifically, children with OI report higher levels of self competence in social, athletic and overall competence if they are walkers. (6) Parenthetically, walking and competence were significantly associated, but these were not correlated with OI type.

Walking is an important activity for this group of children. Gait patterns are frequently abnormal. It is difficult to present grouped data describing the general abnormalities. Nonetheless, children with OI are short statured, have weak pelvic girdle muscles and often have bony malalignment due to curvature of long bones and joint laxity. Biomechanical analyses have shown that generally speaking, OI gait may be characterized as slow, asymmetric when comparing right step and left step characteristics. There is significantly increased amount of pelvic excursion to advance the limb forward. (7)

Strategies have been identified for therapeutic intervention to improve gait. Since strength correlates with gross motor performance measures of ambulation (5) and braces provide a more symmetrical gait pattern (7), strengthening exercises and use of long leg bracing have been used to promote independence in upright activity and ambulation. Data are available supporting the efficacy of braces in the promotion of more strenuous, physical activity, without increased risk of fracture. (7)

We use braces for bony alignment of the lower extremities and have had good clinical results especially in management of foot and ankle laxity. Severe calcaneovalgus and flat foot have been responsive to the use of supramaleolar bracing.

Little data are available to help devise a sensible, safe and effective program for recreational activities. Nonetheless, our data do suggest that participation in recreational activity promotes feelings of competence (6) and there is significant literature on the value of recreation in promoting fitness, and well being. Our recommendations have frequently included the water sports, non-contact sports including bicycling, throwing and tossing balls of various types and usual playground activity. Wheelchair aerobics and T-ball with designated runners are usually well tolerated by most at almost every level of activity. Discussion of treatments for infants and children with OI have been published. (8-11)

Success in life is, in part, dependent upon the ability to achieve goals. Factors that influence successful goal achievement for children with chronic, musculoskeletal impairments include some of the issues raised above (e.g., self-perceived competence, physical limitations of the disease process,) and others. We have also looked at the potential contribution of a child's temperament and the relative protectiveness of families to their ability to perform gross motor activity. Preliminary data suggest that children with OI show the same range of temperament attributes as their non-disabled peers, except that their activity level is lower. The data also indicate that persistence, approach behavior and activity level are all dimensions of temperament that correlate positively with level of physical performance. Parental protectiveness seems to be unrelated to gross motor activity as measured by the Brief Assessment of Motor Performance. (12)

Bibliography:

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12. Marcus SJ, Cintas H, Marini J, Gerber L. Temperament in relation to gross motor function in children with osteogenesis imperfecta. 7th International Conference on Osteogenesis Imperfecta, Montreal, Canada, August 29-September 1, 1999.

Reference: Proceedings of the 7th International Conference on Osteogenesis Imperfecta. Montreal, Canada, 1999.