Abstract:

BACKGROUND: With the aging of population, brittle fracture diseases have attracted more and more attention from clinicians. Bone mineral density detection cannot meet the risk assessment of brittle fracture. As one of the new directions and methods to evaluate the risk of brittle fracture, cortical thickness has been studied and discussed by more and more scholars.

OBJECTIVE: To explore the correlation of bone cortical thickness values and X-ray gray values in different planes of proximal femur with hip brittle fracture in women aged over 50 years old under X-ray DR photography, so as to evaluate the most appropriate measurement plane for predicting the risk of hip brittle fracture in women among different planes of proximal femur.

METHODS: According to the inclusion criteria, relevant clinical data of 100 female patients aged over 50 years old who underwent X-ray DR pelvic radiograph examination at Department of Radiology of the Ninth Affiliated Hospital of Guangxi Medical University from July 2018 to June 2019 were collected. All patients signed the informed consents and the study was approved by the ethics committee of the hospital. The measurement planes of cortical thickness of the proximal femur were designed to be the middle part of femoral neck, within 1 cm above the lesser trochanter, and within 1 cm below the lesser trochanter, with a total of three groups of measurement planes. The gray value of X-ray was measured by taking the line between the middle point of the great rotor and the small rotor as the rectangular diagonal line to take the rectangular area for measurement.

RESULTS AND CONCLUSION: (1) Women aged 50-64 years were as group A (n=50) and those aged 65 years and older were as group B (n=50). (2) The cortical thickness and X-ray gray value within 1 cm below the lesser trochanter, and within 1 cm above the lesser trochanter in the group B were significantly lower than those in the group A; fracture rate was higher in group A than in group B (P < 0.05). There was no significant difference in the cortical thickness of middle part of the femoral neck between two groups (P > 0.05). (3) On the whole, cortical thickness values were highest in the within 1 cm below the lesser trochanter, followed by within 1 cm above the lesser trochanter and lowest in the middle part of the femoral neck (P < 0.05). (4) The correlation coefficient of cortical thickness and X-ray gray value of the within 1 cm below the lesser trochanter and within 1 cm above the lesser trochanter and age to brittle fracture was -0.303, -0.205, -0.272, and 0.346 (P < 0.05). There was no significant correlation between cortical thickness of middle part of the femoral neck and brittle fracture (P > 0.05). (5) The difference of cortical thickness within 1 cm below the lesser trochanter and within 1 cm above the lesser trochanter between fracture and non-fracture groups in the group A was significant (P < 0.05). There was no significant difference in each index between fracture and non-fracture groups in the group B (P > 0.05). At the age above 50 years, the difference of cortical thickness and X-ray gray value in each measured plane between fracture and the non-fracture groups was significant (P < 0.05). (6) To conclude, the cortical thickness becomes thinner and the gray value of X-ray becomes smaller, and the possibility of brittle fracture of hip becomes higher. When assessing the risk of hip fracture in women aged over 50 years using cortical thickness of the proximal femur, measurement within 1 cm below the lesser trochanter is recommended.

Key words: cortical bone thickness, brittle fracture, osteoporotic fracture, women, hip fracture, fracture risk, the National Natural Science Foundation of China