Chulalongkorn Medical Journal


Objective : The objective of this project was to analyze the exact anatomical datacollected from magnetic resonance imaging of Thai patients’ shouldersand to compare their anatomical data with previous studies. Dimensionsprovided from this study can be used to assist implant manufacturersto evaluate the current and future designs.Setting : Department of Orthopaedics, Faculty of Medicine, ChulalongkornUniversityResearch design : Descriptive studyPatients : Sixty-four shoulders / 58 patients who recieved MRI of the shoulder atPrachacheun Imaging Center from January 2008 – December 2008.Methods : All anatomical data of the proximal humerus measured in 3Dreconstruction of the MRI of patient shoulders. We used CATIA tomeasure all parameters and minimize the human errors by using acomputer to calculate a 3D modelResults : The mean of total diameters of the articular was 36.64 ± 4.44 mm.The mean of the male and female shoulders were 40.83 ± 1.36 mm,33.57 ± 2.76 mm respectively. Therefore, the difference betweengenders was significant. The mean articular thickness of the totalsubjects was 15.48 ± 2.38 mm, i.e., the mean of the male; 16.83 ± 2.05 mm; and the mean of the female; 14.50 ± 2.13 mm. The differenceof articular thickness between genders was also significant. The meanneck-shaft angle of all subjects was 137.71 ± 6.43 mm. Separately,the mean of the male and female subjects were 138.80 ± 4.86 mm,136.92 ± 7.32 mm, respectively. The mean medial offset of all subjectswas 5.43 ± 1.51 mm. It is explained that the mean of the male andfemale subjects were 5.29 ± 1.81 mm, 5.53 ± 1.26 mm, respectively.The mean posterior offset of all subjects was 1.15 ± 0.94 mm. Wediscovered the means of male and female subjects were 1.27 ± 0.80mm, 1.06 ± 1.04 mm, respectively. The mean of all retroversion angleswas 13.99 ± 16.17 mm. The means of the male and female subjectswere 10.21 ± 16.16 mm, 16.76 ± 15.82 mm, respectively. Subsequently,the difference of neck-shaft angle, medial offset, posterior offset andretroversion angle between genders were not significantConclusion : All data of this study when we compared to the previous in westernpopulation, we found significant difference in the diameter of thearticular, neck-shaft angle, medial offset and posterior offset. This findingshowed that an implant component suitable for using in westernpopulations may not be compatible to the Thai population. The resultsof the project could provide fundamental data for the future design ofshoulder prostheses suitable for the Thai population.


Faculty of Medicine, Chulalongkorn University

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