Objective To investigate the efficacy and accuracy of 3D printing individualized navigation templates used in shoulder hemi-arthroplasty (HA).Methods We collected 9 adult cadaveric specimens of 18 shoulders with no obvious deformities or defects.After CT scanning was conducted on bilateral shoulders,the raw CT data in DICOM format were imported into software Mimics 10.01 and Imageware 12.0 to reconstruct 3D shoulder models.The retroversion angles and heights of bilateral humeral heads were measured to design individualized navigational templates using software Geomagic Studio 12.0.Rapid prototyping (RP) technique was used to manufacture the individualized navigation templates which were then used to assist shoulder HA in cadaveric specimens.CT scanning was performed postoperatively to measure the retroversion angle and height of the prosthesis implanted for comparison with the preoperative measurements.Results Before shoulder replacement in the 9 cadaveric specimens,respectively,the heights of left and right humeral heads averaged 300.0 ± 11.6 mm and 300.0 ± 11.4 mm,and the retroversion angles 15.6°±4.9° and 15.9°± 4.9°.After the replacement,the heights of left and right humeral heads averaged 300.0 ± 11.3 mm and 300.0 ± 11.7 mm,respectively,and the retroversion angles 15.7° ± 4.9° and 15.8° ± 5.2°,respectively.There were no significant differences between the left and right sides in the pre-or post-operative heights or retroversion angles of the humeral head (P ＞ 0.05).There were no significant differences either between preand post-operation in the heights or retroversion angles of the left and right humeral heads (P ＞ 0.05).The mean errors for the preoperative and postoperative heights and retroversion angles of the humeral heads were 1.44 ± 0.96 mm and 0.25° ± 0.15°,respectively.Conclusion Individualized navigation templates 3D printed can be used to assist effective and accurate shoulder HA because they are designed and manufactured according to accurate measurements of retroversion angles and heights of the humeral heads which are acquired by computer preoperatively.

Objective:To investigate the disability status of the elderly in medical-nursing integrated pension institutions in Beijing and analyze its influencing factors.Methods:Using the convenient sampling method, a total of 359 elderly people from 5 medical-nursing integrated pension institutions in Beijing were selected from May to August 2019. General data and Elderly Disability Assessment Scale (EDAS) were used to evaluate the disability status of the included population, and univariate and multivariate analysis were conducted.Results:A total of 95.3% (342/359) of the elderly had disability. The single factor analysis result showed that male, low education level, a large number of chronic diseases, history of fall, history of smoking, history of drinking, widowed and elderly people living in nursing homes at their public expense were more disabled ( P<0.05) . Multivariate analysis showed that, history of falls, the number of chronic diseases greater than or equal to 3 and widowhood were the influencing factors for aggravated disability ( P<0.05) . Conclusions:In this survey, the rate of disability of the elderly in medical-nursing integrated pension institutions in Beijing is relatively high and the degree of disability is serious. The focus should be on the elderly who are male, with low educational level, smoking history, drinking history, falling history, comorbidities of the aged, the loss of spouse and those who bear the expenses of pension institutions at public expense.