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Objective At present, there is little report of clinical results of metal-on-metal HRA in China.This study was aimed at retrospectively analyzing the factors of survival rate of HRA in China. Methods A retrospective study was conducted in 113 patients who accepted HRA in our hospital from September 2005 to May 2010.All patients were followed up by telephone or outpatient visit,and the average follow-up time was 10.2 years.The clinical function was evaluated by Harris score,and the prosthesis was evalu-ated by pelvic film.Inductively coupled plasma mass spectrometry(ICP-MS)was used to detect the concentration of blood metal ions, ultrasound and MRI were used to screen and diagnose inflammatory pseudotumor.Cox proportional hazards models were used to analyze the factors affecting the survival rate of the prosthesis. Results A total of 91 patients(120 hips)were followed up while 22 patients (26 hips)were lost,the follow-up rate was 80.5%.17 patients underwent revision surgeries,including 8 cases of femoral neck fracture and 8 cases of aseptic loosening,the other one was infection.Revision in 13 cases was within 3 years, the proportion was as high as 76.5%.The 10-year survival rate of prosthesis was 87.1%,the abduction angle of acetabular prosthesis is the only risk factor affecting the survival. Conclusion Postoperative survival rate of HRA is relatively high, and the survival rate of prosthesis is relevant to socket position.We should notice that the risk increased when the acetabular abduction angle of the prosthesis was over 55 degree.O-verall,HRA is still a successful surgical method.
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OBJECTIVE: To evaluate the accuracy of using smartphone to measure the angle of acetabular component in total hip arthroplasty (THA). METHODS: Between June 2012 and September 2015, the acetabular abduction and anteversion angles were measured in 50 patients undergoing THA. There were 24 males and 26 females, aged 37 to 83 years (mean, 71 years). The left hip was involved in 22 cases and the right hip in 28 cases. Of 50 patients, 34 suffered from fracture of the femoral neck, and 16 suffered from avascular necrosis of the femoral head. Acetabular dysplasia was excluded in all cases. A smartphone was used to measure the acetabular abduction and anteversion angles during operation; standard Picture Archiving and Communication Systems (PACS) was used to measured the acetabular abduction and anteversion angles on the X-ray film at 1 week after operation. It was defined as positive that the component angle values by PACS measurement were greater than those by the smartphone measurement, whereas as negative. The two measurement methods were compared, and intra-observer variability was assessed by analyzing the intraclass correlation coefficient (ICC), the Mann-Whitney U-test was used to analyze difference. RESULTS: The ICC was 0.84 in the acetabular component angles by smartphone and PACS measurement methods. The acetabular component abduction angle was (44.02±1.33)° and the anteversion angle was (17.62±2.20)° by smartphone measurement. The acetabular component abduction angle was (44.74±4.05)° and the anteversion angle was (17.22±5.57)° by PACS measurement. There was no significant difference between two measurement methods (Z=-1.977, P=0.482; Z=-0.368, P=0.713). The acetabular component angle was in the safe zone in 44 cases; and the acetabular component anteversion angle was beyond safe range of 1 to 5°, and the abduction angle was beyond safe range of 1 to 3° in 6 cases. Intra-measurement variability was -21 to +10° for the anteversion angle and -10 to + 9° for the abduction angle, indicating that the acetabular component anteversion angle by smartphone measurement was greater than that by the PACS measurement, and the abduction angle was less than that by PACS measurement. CONCLUSIONS: Smartphone is a convenient tool to measure the acetabular component angle in THA.
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Abstract： Objective To study the influence from different placement angles of acetabular component on inner and outer stress distributions of periacetabulum in acetabular reconstruction of total hip arthroplasty (THA), so as to explore proper orientation for improving stability of acetabular component after THA. Methods Based on model with inhomogeneous material property assignment, nine THA models with acetabular component at different anteversion angles(15°, 20°, 25°) and abduction angles(40°, 45°, 50°) as well as one normal hip model were constructed. The maximal hip contact force in phase of single leg stance during normal gait cycle was chosen as the loading condition. In addition, according to the qualitative and quantitative principle, inner and outer stress distributions on 9 THA models were analyzed and compared with the normal hip model as control. Results When abduction angle of acetabular component was the nearest to anatomic angle (19° anteversion, 46° abduction) of acetabulum, the phenomenon of stress shielding on periacetabulum was the most obvious. When abduction angle of acetabular component was placed at 45° and anteversion angle changed from 15° to 25°, no significant influence was exerted on the whole stress distributions of THA models. Meanwhile, when anteversion angle of acetabular component was 15°, the THA model had good stability in stress distributions, and the phenomenon of stress shielding on cortical and cancellous bone was obviously improved. Conclusions For patients who have normal anatomic acetabulum and need to be treated with THA, the abduction angle of acetabular component should be placed at 45°, as that of normal acetabulum; the anteversion angle should be 5° smaller than that of normal acetabulum and between 15° and 20°.
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10.3969/j.issn.2095-4344.2013.26.013
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Adequate first web space is essential for web space expansion, thumb abduction, and a wide range of thumb mobility and hand function activities. First web space contracture is caused by burns, trauma, infection, arthritis, ischemia, paralysis, spastic conditions, improper splinting, Dupuytren's contracture, or congenital anomaly. We have treated 18 cases of first web space contracture from Nov. 1, 1996 to Apr. 30, 2000 using 23 various flaps. Four measurements such as maximal abduction angle, maximal abduction distance, radial abduction angle, and palmar abduction angle were examined preoperatively and postoperatively. We have classified first web space contracture as mild, moderate, or severe depending upon the magnitude of contracture and scarring of the first web contents (skin, fascia, muscle and joint capsule). We have performed hree Z-plasty, three double opposing Z-plasty, and two 4 flap Z-plasty in 6 mild contracture. We have performed two Z-plasty and F.T.S.G, two dorsal rectangular flap and F.T.S.G, two F.T.S.G, and two S.T.S.G in 5 moderate contracture. We have performed two distant flaps and five free flaps in 7 severe contracture. Periods of follow-up were from 12 months to 35 months with an average of 15 months. Every patient was analyzed by the ratio of postoperative measurements to preoperative measurements. The mean ratios of mild, moderate, and severe contracture were 1.33, 1.28, and 1.38 respectively. Although first web space contracture was severe, its ratio was more improved than that of mild or moderate contracture because of complete release and abundant soft tissue coverage such as first web space free flap. The proper methods of first web space contracture release in accordance with the classification allowed to achieve excellent results.