Objective To investigate the effectiveness of total hip arthroplasty with double-tapered cementless femoral stem for hip bony fusion by comparing with anatomical cementless femoral stem. Methods A retrospective analysis was made on clinical data of 50 cases (80 hips) of hip bony fusion undergoing total hip arthroplasty between October 1999 and January 2008. The patients were divided into 2 groups: 31 cases (49 hips) using BetaCone double-tapered cementless femoral stem (trial group), and 19 cases (31 hips) using Ribbed anatomical cementless femoral stem (control group). There was no significant difference in gender, age, disease duration, preoperative Harris score, and abduction angle of the hip between 2 groups (P gt; 0.05). After operation, X-ray films were used to calculate the ratio of force arm of abductor (a) to the force arm of gravity (b) and analyze the stability of the prosthesis. The abduction angle of the hip and Harris score were measured during follow-up. Results Fracture occurred during operation in 9 hips of 9 cases (5 in trial group and 4 in control group), and was cured after fixation. The mean follow-up time was 49 months (range, 12-98 months) in trial group and was 53 months (range, 6-105 months) in control group. The ratio of a/b was 0.65 ± 0.25 in trial group and was 0.56 ± 0.37 in control group, showing significant difference (t=2.19, P=0.03). The abduction angle of hip was (34.49 ± 7.58)° in trial group and was (30.97 ± 7.24)° in control group at 6 months after operation, which was significantly improved when compared with preoperative value in 2 groups (P lt; 0.05), and significant difference was found between 2 groups (t=2.06, P=0.04). Postoperative Harris score was significantly improved in 2 groups when compared with preoperative score (P lt; 0.05); trial group was better than control group in Harris score at 1 month after operation (t=3.62, P=0.01), but no significant difference was found between 2 groups at last follow-up (t=1.61, P=0.11). At last follow-up, X-ray films showed stabilized prosthesis in 2 groups. Grade I or II ectopic ossification occurred in 12 cases (14 hips) of trial group and 8 cases (9 hips) of control group at 2 years after operation. Conclusion The total hip arthroplasty with both double-tapered and anatomical cementless femoral stems for hip bony fusion can obtain satisfactory effectiveness, while the double-tapered cementless femoral stem has better abduction angle of hip.
Objective To investigate the medium-term effectiveness of straight tapered rectangular femoral prosthesis in total hip arthroplasty (THA). Methods Between May 2004 and June 2006, 58 cases (61 hips) of hip joint disease underwent THA with straight tapered rectangular femoral prosthesis and the clinical data of 43 cases (45 hips) followed up more than 6 years were retrospectively analyzed. There were 21 males (23 hips) and 22 females (22 hips) with an average age of 51.6 years (range, 25-75 years), including 12 cases (12 hips) of congenital developmental dysplasia of the hip, 1 case (1 hip) of osteoarthritis secondary to acetabular dysplasia, 1 case (1 hip) of hip deformity after poliomyelitis, 9 cases (9 hips) of femoral neck fractures, 8 cases (8 hips) of avascular necrosis of the femoral head, 8 cases (8 hips) of osteoarthritis of the hip joint, 2 cases (3 hips) of rheumatoid arthritis, and 2 cases (3 hips) of ankylosing spondylitis. Unilateral replacement was performed in 41 cases and bilateral replacement in 2 cases. The Harris score was 41.7 ± 10.4 before operation. X-ray examination was performed to analyze the location of femoral prostheses and evaluate the stability of the prosthesis-bone interface, and Harris score was used to evaluate the hip function. Results Periprosthetic fracture occurred in 3 hips, and thigh pain in 4 hips after operation. Forty-three cases (45 hips) were followed up 74-99 months (mean, 85 months). Harris score was 87.6 ± 8.3 at last follow-up, showing significant difference when compared with preoperative score (t=23.14, P=0.00). The X-ray examination showed that 9 hips had heterotopic ossification; bone resorption caused by stress shielding was observed at the proximal femur in 42 hips. But the stability of the prosthesis-bone interface was good; no infection or dislocation occurred; and no revision for aseptic loosening was performed in all cases. The survival rate of the femoral prosthesis was 100% during medium-term follow-up. Conclusion THA with straight tapered rectangular femoral prosthesis has good medium-term effectiveness.
It is an important means to study the electrical activity of the brain's nerve cells by exploring physiological information of the EEGs from the frequency domain. The gravity frequency is one of the global parameters with using this method. We used the multitaper spectrum method (MTM) spectrum estimation method of good performance to calculate the EEG spectrum and its gravity frequency of subjects under vigilance and vigilance decrement state. The results showed that the gravity frequency of vigilance state was higher than that of vigilance decrement state, the gravity frequency became smaller along with the vigilance decrement, and the location of the gravity frequency shifted to the left in the spectrum. Finally, the monitoring curve of the gravity frequency was acquired by designing an algorithm, and it was used to online monitoring vigilance operators.
The aim of the present experimental study is to determine the effects of sinotubular junction diameter on artificial bioprosthesis valves. An experimental study was performed for aortic root models with different sinotubular junction taper under pulsatile flow condition. The sinotubular junction diameters were modified to create four models with different sinotubular junction tapers with 0, 1, 3 and 5 degrees, respectively, using three dimensional printing techniques. After installing the testing bioprosthesis valve on the aortic root models, we conducted experiments of the pulsatile flow testing with different stroke volume in the pulsatile circulation simulation system. The testing condition was set at the pulse frequency of 70 beats/min and the stroke volume of 2–7 L/min. The status of the valves in 10 continuous pulse cycles was tested and the average results were obtained for each stroke volume. The results of testing showed that the mean transvalvular pressure gradients agreed well with the national standard, and all smaller than 10 mm Hg. The sinotubular junction taper had an influence on regurgitation fraction of the artificial bioprosthesis valve. The smaller sinotubular junction taper showed beneficial effect to decrease the regurgitation fraction. In the case of smaller stroke volume, the smaller sinotubular junction taper was beneficial to increase the effective valve orifice area. In the case of larger stroke volume, the larger sinotubular junction taper was beneficial to increase the effective valve orifice area. This study indicates that a doctor should consider the smaller sinotubular junction taper in the case of smaller stroke volume more. In the case of larger stroke volume, the doctor should consider the larger sinotubular junction taper more.