Introduction: Metaphyseal inwaisting is a process that occurs during long bone growth and remodelling of epiphyses and results in a proportional increase in growth plate width (GPW) and a decrease in metaphyseal width (MW). The Metaphyseal Index (MI) compares GPW to MW, usually in the distal femur. However, due to bone-age assessments, the most commonly performed radiograph in children is that of the hand/forearm. Previous work showed that gymnasts have a more widened growth plate at the distal radius than normal children, but these studies did not quantify the morphological changes using the MI and pQCT measures. Previous studies have shown that the use of DXA hand/forearm images for the purposes of bone-age assessment were unreliable for children aged 11 and under. Aims: Examine distal radius morphology of 378 Normal subjects (155 male), 36 Gymnast subjects (15 male), 17 NF1 subjects (7 male) and 108 CDGP subjects (83male) to calculate the precision of MI, MW and GPW measurements, to determine a normal reference range for the MI in Normal subjects and use this to compare to the other 3 groups, and to compare longitudinal measurements. Also, to investigate whether DXA software upgrades have improved the ability to make TW3 bone-age assessments, to investigate how closely DXA compares with standard radiographs using 98 (38 male) DXA hand images and radiographs, and calculate the precision (CV%) of the GP and TW3 bone-age assessment methods. Methods: Anthropometric data, Tanner stage, posterior-anterior hand radiographs and pQCT scans of the non-dominant hand/forearm were obtained. MI was measured using a semi-automated computer-assisted method. Statistical analyses were used to compare males and females, and compare the Normal group to other groups. Also, DXA images and radiographs were assessed by the same assessor and the TW3 and GP bone-ageing methods were compared. A CV% was calculated for both comparisons. Results: The CV% of MI, MW and GPW = 1.05%, 0.92% and 1.28% respectively. MI of males and females was not statistically different in any group. The MI of Gymnasts was significantly lower than the Normal group (p = 0.008). The NF1 and CDGP groups were not significantly different from the Normal group. Longitudinal measurements indicated those with a low/high MI at the first visit were likely to have a low/high MI at the second visit, though occasionally the MI would decrease between visits. DXA bone age assessments proved to be reliable in subjects of all ages assessed in this study and showed a CV% only slightly higher than standard radiographs (CV = 2.95% DXA vs2.68% radiograph). The CV% of GP and TW3 methods = 2.68% & 1.61% respectively. Discussion: The CV% of MI, MW and GPW shows these methods to be very precise. The mean MI of gymnasts is significantly lower than in normal children due to a widening of the growth plate and not due to a reduction in metaphyseal width. Insufficient subject numbers and smaller age ranges, particularly in the Gymnast and NF1 groups may play a part in the non-significant differences between them and the Normal group. DXA CV% shows that DXA is almost interchangeable with standard radiographs. The TW3 and GP CVs% show that TW3 bone-age assessment is more precise than the GP method. This confirms the tight control that the MW and GPW have in proportion to each other. This is the first study to quantify changes in distal radius morphology in normal, athlete and disease groups, and create a range of normal reference values, which could be useful for future work in this area.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:538419 |
| Date | January 2011 |
| Creators | Reddie, Lianne Catherine Rose |
| Contributors | Adams, Judith ; Astley, Susan |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/a-study-of-growth-and-development-in-the-distal-radius-using-the-metaphyseal-index(012d3c1d-8e2a-44ac-9b4f-dd3084e33714).html |
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