CHILDREN’S HIPS: INNOVATION IN THE DIAGNOSIS, MONITORING AND TREATMENT OF CHILDREN’S HIP DISEASES
Perthes’ disease is an idiopathic osteonecrosis of a developmental hip that is most frequent in Northern Europe. Currently, the absence of a common set of standardized outcomes makes comparisons between studies of different interventions challenging. The overarching aim of this thesis was to understand and enhance the important clinically relevant outcomes that should be measured in Perthes’ disease. A protocol was devised to define a set of core outcomes (COS) (Study 1), which involved a systematic review of the literature, patient and associated family interviews and a Delphi survey. In Study 2, 18 parents were interviewed and perspectives of 12 children affected by Perthes’ disease (mean 7.1 years, SD±4.1 years) were explored using a survey tool. Thematic analysis of the parents interviews (main themes n=4) identified a marked effect of the disease on many facets of the child’s life, particularly pain and the impact on sleep, play and school attendance. Study 3 followed the guidelines of the COMET-Initiative (Core Outcome Measures in Effectiveness Trials) to define a COS for Perthes’ disease. The outcomes from the systematic review, together with the domains collected in Study 2, formed the basis of a Delphi survey (2 rounds), where 18 patients with Perthes’ disease, 46 parents and 36 orthopaedic surgeons rated each outcome for importance. A final consensus meeting among representatives of surgeons, patients and parents voted 14 outcomes to be included in the final Core Outcomes Set. Following the systematic review of previous studies (n=112), 33 outcomes were identified. After round 1 of the Delphi survey, participants suggested additional 5 outcomes, therefore a total of 38 outcomes were scored in round 2 of the Delphi. Among these, 16 outcomes (divided in 6 main categories: adverse events; life impact; resource use; pathophysiological manifestations; death; technical considerations) were scored over the 70% threshold for importance. After feedback from final consensus meeting, a total of 14 outcomes were included in the final Core Outcomes Set (COS). The results of Study 3 highlighted that hip mobility is an important outcome to measure in clinical trials for Perthes’ disease, but to date there is no system able to continuously monitor hip angle in children. Thus, Study 4 aim was to develop a wearable device capable of continuously monitoring joint mobility in both laboratory and everyday life environments. The wearable device developed consists of a microcontroller (ATMEL ATtiny85), with an optical flexible sensor, furnished with a Bluetooth shield (to allow wireless monitoring) and a local storage system (I2C EEPROM), which is worn on the joint of interest. The device demonstrated good accuracy compared to a gold standard goniometer when measuring hip and knee during flexion and extension with a Standard Error of Measurement (SEM) of ±0.27 degrees at 95% confidence interval. When everyday activities were simulated in the laboratory, including walking and sitting (half-squat test), the device was able to retrieve information about the joint angle in real time. The reduced mobility of the hip joint in childhood hip diseases may affect the physical activity (PA) level of children, promoting a sedentary lifestyle. Study 5 aimed to investigate the relationship between hip mobility (assessed with the current clinical tool for hip mobility- PROMIS questionnaire) and objectively measured PA in children with hip diseases. Twenty-eight children (12 boys and 16 girls) aged between 8 to 17 years old (mean 12±3 years) were recruited for the study. A bivariate Pearson Correlation test (two-tailed) found a moderate correlation between the normal score of hip mobility and the average daily LPA (r=0.46, n=28, p=0.01). Additionally, a moderate to strong positive correlation (r=0.67, n=28, p=0.01) between normal scores of hip mobility and increased participation in moderate-to-vigorous PA (MVPA), and a positive moderate correlation (r=0.54, n=28, p=0.01) among normal scores of hip mobility and increased participation in vigorous PA (VPA) were found. Children with hip diseases surprisingly reported a higher level of MVPA compared to the general population, however their sedentary time was higher than the general population. In summary, the work undertaken in this thesis has (i) defined a COS that can be employed in future clinical trials for Perthes’ disease; (ii) defined a prototype of a low cost wireless monitor to assess hip mobility, as relevant outcome in the COS for Perthes’ disease, in children with hip diseases; (iii) shown that the current clinical tool to assess hip mobility in childhood hip diseases is strongly correlated with objectively measured physical activity. Further research is required to identify and refine the tools to measure the outcomes defined in our core outcomes set.
RC1200 Sports Medicine, RJ Pediatrics, RJ101 Child Health. Child health services
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