Objective To explore the expressions of bone morphogenetic protein 2 (BMP-2) and runt-related transcription facotr 2 (Runx2) and microarchitecture of trabecular bone periacetabula in adult patients with developmental dysplasia of the hip (DDH). Methods Between March and September 2008, the trabecular bone periacetabulum was collected from 8 patients with DDH who were scheduled for total hip arthroplasty (aged 37-55 years, 3 males and 5 females, trial group) and from 8 patients with avascular necrosis of the femoral head (Ficat stage II) who were scheduled for hip resurfacing arthroplasty (aged 36-55 years, 3 males and 5 females, control group). The expressions of BMP-2 and Runx2 in the trabecular bone were determined by real-time quantitative PCR, and the microarchitecture was observed by micro-CT and the following parameters were determined: bone volume/total volume (BV/TV), connectivity density (Conn.Dens), trabecular number (Tb. N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and structure model index (SMI). Results The expressions of BMP-2 and Runx2 were significantly lower in trial group than in control group (P lt; 0.05). The micro-CT showed sparse trabecular bone in trial group and dense trabecular bone in control group. BV/TV and Tb.N in trial group were significantly lower than those in control group, and SMI and Tb.Sp in trial group were significantly higher than those in control group (P lt; 0.05); there was no significant difference in Conn.Dens and Tb.Th between 2 groups (P gt; 0.05). Conclusion The trabecular bone is in a low metabolism condition and its microarchitecture is tendency to be osteoporosis trabecualr bone in adult patients with DDH. It may be related with the acetabular component loosening after total hip arthroplasty.
Objective To analyze the main reasons of acetabular component initial instabil ity after primary total hip arthroplasty (THA) and to disscuss the prevention and management. Methods The cl inical data were retrospectively analyzed from 19 patients undergoing revision for acetabular component initial instabil ity after primary THA between January 2003 and June 2010. There were 11 males and 8 females, aged from 55 to 79 years (mean, 67.2 years). The locations were lefthip in 9 cases and right hip in 10 cases. The cementless hip prosthesis was used in 12 cases and cement hip rosthesis in 7 cases. The revisions were performed at 3 weeks to 6 months after primary THA. The reasons of early failure were analyzed. Both the coverage rate of acetabulum-bone and the Harris hip score were compared between pre- and post-revision. Results The main reason of acetabular component initial instabil ity after primary THA may be unsuitable treatment of acetabulum, improper selection of acetabular component, and incorrect place angle of acetabular component. Sciatic nerve palsy occurred in 1 case and recovered at 7 weeks after revision. Sl ight fracture of the acetabulum in 1 case and healed at 3 months after revision. All incisions healed by first intention. No infection, vessel injury, displacement of acetabular component, or deep vein thrombosis occurred. The patients were followed up 11-73 months (mean, 28 months). At last follow-up, no acetabular component instabil ity was observed. The coverage rate of acetabulum-bone was increased from 67.9% ± 5.5% before revision to 87.7% ± 5.2% after revision, showing significant difference (t=11.592，P=0.003). The Harris hip score at last follow-up (84.4 ± 4.6) was significantly higher than that at pre-revision (56.5 ± 9.3) (t=11.380，P=0.005). Conclusion Detailed surgical plan, proper choice of component, correct place angle and elaborative planning, and proficient surgical skill are necessary to achieve the initial stability of acetabular component in THA．
Objective To improve the accuracy of the acetabular component placement using the nonimage based surgical navigation system. Methods Twenty-three patients (14 males, 9 females; age, 28-55 years;26 hips）with hip disease underwent the total hip arthroplasty (THA) using the nonimage based surgicalnavigation system from February 2004 to April 2006. Rheumatoid arthritis was found in 3 patients (3 hips), necrosis of the femoral head in 6 patients (6 hips), and osteoarthritis in 14 patients (16 hips). All the patients were randomly divided into the following 2 groups: the navigated group (11 patients, 13 hips), treated by THA using the nonimage based surgical navigation system; and the control group (12 patients, 13 hips), treated by the traditional THA. According to thedesign of the study, the acetabular component was placed in the best inclination angle (45°) and the anteversion angle (15°). The postoperative component position was examined. Results No fracture, dislocation, infection or injury to the sciatic nerve was found. In the navigated group, the inclination and the anteversion reached 15.4±1.4° and 45.5±1.3°, respectively. In the control group,the inclination and the anteversion were 13.9±7.6° and 43.7±6.4°, respectively. The inclination difference was considered statistically significant (Plt;0.01). All the patients were followed up for 10-40 months,averaged 26 months. In the navigated group, the postoperative average Harris hip score was 95 (range,85-110), with an excellent result in 11 hips and a good result in 2 hips. In the control group, the postoperative average Harris hip score was 92 (range,75-110), with an excellent result in 9 hips, a good result in 3 hips, and a fair result in 1 hip. The Harris hip score difference was considered statistically significant (Plt;0.05). There was a significantly better result obtained in the navigated group than in the control group. Conclusion The acetabular component can be implanted accurately by the nonimage based surgical navigation system, which can reduce the incidence of the loosening of the prostheses and has an important value in clinical practice.
Objective To set up the experimemtal model with superior segmentalbone defect in acetabulum and implant the three-fin acetabular component, and examine the Von Mises stresses of pelvis bone with simulating single leg position in vitro using rosette strain gages method(RSGD). Methods Four kinds of three-fin components were made based on measurement of diameter, depth and roof thickness of acetabular specimens. These kinds of threefin acetabular components based on spreaded degrees of lateral fins(0,36,45 and 60°). The superiorsegmental bone defect of acetabulum in 4 cadaver pelvis specimens was made,then simulated the actual position to place implant into acetabular bone.A blank control group was set up.After being fit up the 7 sets of rosette strain gages,then specimen to test the pelvic Von Mises stresses simulating the static load of single leg on the mechanic machine.Progressive load was graded into 150, 300,450, 600, 750 and 900 N.We obtained the strains informations about loaded andun-loaded pelvis bone. Results Based on computed the strains informations,we were informed the Von Mises stresses about pelvis bone.The maximal Von Mises stresses of selected local position was 6.93 MPa and the minimal Von Mises stresses of selected local position was 1.08 MPa. Conclusion Providing the data about the mainpart of threefin acetabular component to optimize spreaded degrees of lateral fins.
ObjectiveTo evaluate the accuracy of using smartphone to measure the angle of acetabular component in total hip arthroplasty (THA). MethodsBetween 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. ResultsThe 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. ConclusionSmartphone is a convenient tool to measure the acetabular component angle in THA.