Methods Of Measuring Glenoid Bone Loss In Anterior Instability Shoulder

The Symmetry Study for Normal Bilateral GlenoidObjective: The purpose of of this study is to critically analyze the structural symmetry of both glenoids in an objective and quantitative manner to ascertain the degree of symmetry present by measuring the maximum width,maximum length and surface area of bilateral shoulder glenoid in normal person.Methods:The study cohort comprised 40 subjects(20 males and 20 females,average age of 38.8±5.6)with no shoulder pathology or injury from Jan 1,2017.1 to Dec 31,2019.12.The Data scanned by CT was used to construct 3-dimensional images of the bilateral glenoid,it is imported into Mimics software and 3-matic software for modeling an exact model and measurement.Measuring the the maximum width,maximum length and surface area of bilateral shoulder glenoid,and the data were collected and statistically analyzed.Results: 40 subjects was included in the study;The mean percentage maximum width(left side26.58±2.88 mm,right side27.84±4.4mm),the maximum length(left side 38.73±5.17 mm,right side39.27±4.19mm),the surface are(a left side 714.41±146.46 mm ~2,right side 718.71±147.12 mm ~2),analysis showed no significant shape difference between both glenoids(P>0.05).Conclusion: In normal subjects,the maximum width,maximum length and surface area of both glenoids are highly symmetric in size.A Clinical Comparison of Two Methods of Measuring Glenoid Bone Loss in Anterior Instability ShoulderObjective: In this study,two methods were used to measure and quantify the glenoid defects of patients with anterior instability of shoulder,and the differences between the two methods were compared to guide the clinical treatment of anterior shoulder instability.Methods: The imaging data of bilateral shoulder CT in 20 patients with anterior shoulder instability were collected.The data in DICOM format were imported into the software of Mimics to model the bilateral scapula.On the established model,"AP center method" and "surface area method" were used to measure the degree of glenoid defect,and the data were collected and analyzed statistically.Results:The average rate of glenoid defect calculated by "AP center method" was 11.93% ± 5.70%,and that calculated by "surface area method" was 7.35% ± 3.28%.The difference between the two methods was statistically significant(P = 0.004).15% of the defects were determined as the critical value of bone surgery by "AP center method".20 patients were divided into two groups: "defect < 15%" and "defect > 15%".In the "defect < 15%" group,the defect rate "AP center method" was 8.62% ± 3.51% and the "surface area method" was 5.76% ± 2.529%.In the "defect > 15%" group,the "AP center method" was 18.06% ± 3.29% and the "surface area method" was 10.29% ± 2.26%.There was statistical difference between the two methods(P < 0.05).In the "defect > 15%" group,the difference between the two methods was significant;The average rate of glenoid defect was 14.83% ± 5.52% by "AP center method" and 8.94% ± 2.79% by "surface area method".The difference between the two methods was statistically significant(P = 0.007).Conclusions: 1.In the measurement of glenoid defect,the results of "AP center method" are significantly greater than "surface area method",and the two methods can't be replaced.The discussion of the critical value of anterior shoulder instability should be carried out on the premise of indicating the specific measurement method.2."Surface area method" is more intuitive,accurate and repeatable than "AP center method" for the measurement of shoulder glenoid bone defect.