Objective:To compare the early efficacy of direct anterior approach versus posterolateral approach for total hip arthroplasty in elderly patients.Methods:The 48 elderly patients receiving total hip arthroplasty from September 2017 to September 2019 were divided into two groups: DAA group(n=23, 30 hips)receiving direct anterior approach for total hip arthroplasty, and PLA group(n=25, 33 hips)receiving posterolateral approach for total hip arthroplasty in this retrospective study.The operation time, blood loss, length of hospital stay, acetabular abduction angle, anteversion angle, and intraoperative and postoperative complications were recorded and compared between the two groups.The hip function was compared with Visual Analogue Scale(VAS)and Harris Hip Score(HHS).Results:All the 48 patients were followed up for 7-31 months, with an average of 22.8 months in DAA group, and 24 months in PLA group.The operation time was less in PLA group than in DAA group[(49.3±5.7)min vs.(70.3±6.2)min, t=12.22, P=0.00], while the hospital stay was longer in PLA group than in DAA group, with a statistically significant difference[(7.8±1.5)d vs.(5.6±1.3)d, t=-5.40, P=0.00]. There was no significant difference in intraoperative blood loss between the two groups[(173.1±47.9)ml vs.(189.6±48.7)ml, t=1.18, P=0.24]. The VAS and HHS scores were better at 1 month after operation and at the last follow-up than before operation in both DAA and PLA group(all P<0.05). The VAS and HHS scores were better in DAA than in PLA groups( P<0.05)at 1 month after surgery.However, at the last follow-up, there was no significant difference in VAS and HHS scores between the two groups( P>0.05). Conclusions:The early results of direct anterior approach for total hip arthroplasty are satisfactory in patients aged 85 years and older.It has the advantages of less trauma, faster postoperative recovery and shorter hospital stay.

Objective:To establish the basic procedures of the application of optical surface monitoring system (OSMS) in the deep inspiration breath hold (DIBH) radiotherapy for patients with left sided breast cancer and compare the performance of OSMS and cone-beam CT (CBCT) in the determination of the set-up errors of DIBH radiotherapy for patients with left sided breast cancer.Methods:Twenty patients with left sided breast cancer received DIBH radiotherapy. Through the registration of CBCT images with the planning CT images, and the registration of OSMS radiography images with the outer contour of the body surface, translational set-up errors and rotational errors were determined along the lateral-medial ( Rx), superior-inferior ( Ry) and anterior-posterior ( Rz) directions. Pearson correlation analysis was performed to evaluate the correlation of the set-up errors determined by two methods, and Bland- Altman plot analysis was used to assess the coincidence of these two methods. Results:Two methods were positively correlated. The Rz volume was 0.84, 0.74 and 0.84 in the x, y and z directions, and 0.65, 0.41 and 0.54 in the Rx, Ry and Rz directions, respectively (all P<0.01). The 95% CI of agreement were within preset 5 mm tolerance (-0.37-0.42cm, -0.39-0.41cm, -0.29-0.49cm ) in x, y and z directions for two methods. The 95% CI of agreement were within preset 3 ° tolerance -2.9°-1.4°, -2.6°-1.4°, -2.4°-2.5°in Rx, Ry and Rz directions for two methods. The system errors of 20 patients with left sided breast cancer receiving DIBH radiotherapy were <0.18cm and the random errors were <0.24cm. Conclusions:OSMS is equivalent to CBCT in the determination and stimulation of set-up errors for patients with left sided breast cancer receiving DIBH radiotherapy. The combination of CBCT and OSMS is a safe and reliable method.