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Objective To investigate the trabecular stress distributions on the cortical bone and determine whether the cancellous bone can share the load of the acetabulum with a press-fit acetabular cup. Methods The acetabulum was scanned via micro-computed tomography (CT) to build a three-dimensional micro-finite element analysis (μFEA) model of the acetabulum. The trabecular stress and strain of the bony acetabulum were calculated following total hip arthroplasty (THA) to investigate the biomechanical characteristics of their distributions. Results With the implantation of the press-fit acetabular cup into the acetabulum, the high-stress zone of the articular surface was found to be located in the pubic bone area, with a maximum stress of 1.398 MPa. The largest high-stress zone within the articular surface was at the craniomedial part where it was supported by the iliac. For the cancellous bone within the acetabulum, the high stress was relatively widely distributed on the craniomedial part. When a 1.372 kN load was applied, the high stress was found at the craniomedial and anterior-inferior parts of the articular surface where it was supported by the iliac and pubic bone, with a trabecular micro-damage occurring in the anterior-inferior part. The highest tensile stress at the craniomedial part was 0.604 MPa. For the cancellous bone within the acetabulum, the high stress was mainly distributed on the craniomedial and anterior-inferior parts. Conclusions The high stress near the periphery of the articular surface showed a three-point circular distribution, which was mainly distributed on the iliac, ischial, and pubic bone area. The stress was distributed more uniformly owing to the deformation of the cancellous bone in the acetabulum. The cancellous bone in the acetabulum has the function of load-bearing.
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Objective To evaluate the clinical efficacy of combined anteversion angle of femoral neck-acetabulam in Crowe Ⅳ developmental dysplasia of the hip (DDH) with Wagner Cone total hip arthroplasty. Methods From June 2013 to February 2016,45 cases of CroweⅣDDH were treated with no femoral shortening osteotomy in THA ,including 25 females and 20 males. The outcomes of anteversion angle of femoral neck and acetabulam were measured in CT scan of hip jiont. The outcomes of abduction angle ,hip center were measured radiologically in X-ray of pelvis. Postoperative function was scored by Harris scoring system. Results The mean follow-up time of the 45 patients was(3.2 ± 0.8)years. Using loosening or revision as the end point ,the survival rate was 100%. The outcomes of preoperative anteversion angle of acetabulam,femoral neck,acetabulam-femoral neck was(27.70 ± 5.35)°,(47.76 ± 7.25)°,and(74.90 ± 8.43)° in CroweⅣgroup,and those of postoperative anteversion angle was(19.82 ± 2.41)° ,(23.35 ± 3.84)° and(44.90 ± 5.18)° ,respectively. There was significant difference between the two groups(P < 0.05). The average height of preoperative dislocation in femoral head was (5.8 ± 1.2)cm and the postoperative average displacement of femoral lesser trochanter was (3.6 ± 0.8)cm. The Harris hip score was improved from preoperative(46.66 ± 7.28)to(90.36 ± 4.72). For most patients,hip pain were significantly relieved ,range of motion of the hip was improved ,and the gait returned to normal. Femoral nerve injury occurred in 2 cases and the case recovered after 3 months respectively. Conclusions The deformity of hip and the stability and matching degree of the prosthesis was evaluated with the combined anteversion angle of femoral neck-acetabulam in CroweⅣDDH. The Wagner Cone can effectively maintain the stability of the hip joint in the non-amputated total hip replacement.
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Objective To evaluate the results of computer-aid customized acetabular cages for patients with severe defects.Methods Twenty-three patients (8 males and 15 females) with a massive acetabular defects were involved in the present study from January 2005 to September 2014.The average age was 64.2 years (range,46-79 years).According to the American Academy of Orthopaedic Surgeons (AAOS) classification,20 had AAOS type Ⅲ defects and three had AAOS type Ⅳ defects.The customized cages were individualized to each patient's bone defects based on the rapid prototype three-dimensional printed models.The mean follow-up duration was 66.3 months (range,24-120 months).The clinical and radiographic outcomes of all patients were assessed at 6 and 12 weeks after surgery and at once yearly thereafter.Harris hip scores were assessed before surgery and at each follow-up.Postoperative radiographs were evaluated for cage position,migration,and graft incorporation.Complications and reoperations were assessed by chart review.Results The mean Harris hip score improved from 36.2±7.9 (range,20-49) to 81.8± 8.4 (range,60-96),and there is a significant difference between pre-and post-operation (t=23.23,P＜0.001).Individualized custom cages resulted in generally reliable restoration of the hip center.The difference of horizontal distance (between the center of each hip and pubic symphysis) between bilateral sides was-3.0±6.4 mm (range,-19-8 mm).The difference of vertical distance (between the center of each hip and the line connecting the inferior border of the bilateral tear drop) between bilateral sides was 0.4±2.8 mm (range,-4.5-5 mm).No re-revisions had been conducted.None of the cups showed radiographic migration,while one cage was suspected to be loose based on a circumferential 2-mm radiolucent line.Cancellous allografts appeared to be incorporated in 22 of 23 patients.One deep infection and one superficial infection were observed and were treated with irrigation,debridement,and vacuum sealing drainage.One dislocation and one suspected injury of the superior gluteal nerve also were observed and were treated conservatively.Conclusion Individualized customized cages appears to provide stable fixation and improve hip scores at short or mid-term follow-up.
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Objective To assess the functional restoration in patients with developmental dysplasia of the hip (DDH) who underwent hip resurfacing arthroplasty and to determine whether greater abduction angle of the acetabular component is relat?ed to larger diameter of femoral head component. Methods We reviewed 34 DDH cases (9 hips of 8 males and 25 hips of 24 fe?males, mean age 44.6±11.85 years at the time of surgery) on whom we performed hip resurfacing arthroplasty (HRA) from October 2006 to September 2009. The total hip Arthroplasty (THA) group was consisted of 35 DDH cases (8 hips of 8 males and 27 hips of 25 females, mean age 43.7±10.4 years at the time of surgery). All operations were performed by the same doctor over the same peri?od. Assessment of the functional hip scores was conducted by Harris Hip Scores. A radiographic study was also performed to evalu?ate the implants stability and abduction angle of the acetabular components. All the data was analyzed with Kolmogorov?Smirnov method. Results The mean follow?up was 6.2 years in the HRA group. The Harris Hip Score improved from 54.9±13.2 to 97.3± 6.2 after the surgery. The mean abduction angle of the acetabular component was 51.6° ± 5.33°, hip flexion was 127° ± 6.9° and mean diameter of femoral head was 46.5±1.5 mm. The mean follow?up was 5.9 years in the THA group. The Harris Hip Score im?proved from 51.6±19.7 to 95.6±7.9 after the surgery. The mean abduction angle of the acetabular component was 43.9°±4.90°, hip flexion was 117°±4.2°. There was no failure of the prosthesis, peri?prosthetic fracture and infection in either group. There was sig?nificant difference in the abduction angle of the acetabular component (P<0.05) and flexion of the hip between the two groups (P<0.05). Conclusion Patients in the HRA group had a better functional restoration and larger range of motion. Furthermore, a larger diameter of femoral head component could be achieved by placing the acetabular component in a greater abduction angle, which may contribute to a better long?term stability.
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Objective To evaluate the clinical efficacy of total hip arthroplasty (THA) with no femoral shortening oste?otomy for unilateral CroweⅣ developmental dysplasia of hip. Methods From October 2007 to January 2010, 32 patients with CroweⅣdevelopmental dysplasia of hip in one side underwent THA, including 20 females and 12 males, with an average age of 49.4 ± 9.7 years (range, 23-60 years). There were 15 cases as normal and 17 as mild developmental dysplasia of hip in the other side. The THA were performed with requisite soft tissue release and direct leverage using an elevator but with no femoral shorten?ing osteotomy. The patients' satisfaction, Harris hip score, bilateral leg?length discrepancy and pelvic obliquity was used to assess the clinical results. Results All of patient were followed up for 1-6 years, average 4.0 ± 1.5 years. No loosening or failure of component occurred by the end of follow?up. The Harris hip score was improved from preoperative 36.5±10.3 (20-63) to 89.8± 4.9 (80-97), and the excellent and good rate was 100% (excellent 16 cases, good 16 cases). The satisfactory rate was 93.8%(30/32). The leg?length discrepancy of the bilateral sides and the pelvic obliquity was corrected gradually and the gait returns to normal. Nine cases have valgus knee after THA and 4 cases of them felt uncomfortable after long?distance walk. Femoral nerve injury occurred in 2 cases. All of cases recovered after 1 and 3 months respectively. No infection and dislocation oc?curred. Conclusion THA with no femoral shortening osteotomy can achieve good clinical results in patients with unilateral CroweⅣdevelopmental dysplasia of hip. The discrepancy of leg?length will be diminished with the correction for pelvic obliquity.
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Objective To evaluate the clinical outcome of total hip arthroplasty (THA) for protrusio acetabuli. Methods Between 2003 to 2008, 31 patients(35 hips) with protrusio acetabuli were treated with THA, including 16 males (18 hips) and 15 females (17 hips). The age ranged from 36 to 71 years (average age 52.2 years). The femoral heads were moved out with retrograde method when necessary via posterior-lateral hip incision. The acetabular loops and bottoms were prepared respectively. Auto-bone grafting was used to repair acetabular defects and cementless prostheses were planted with press-fit skills. At follow-up visit,the hip functions were evaluated by Harris score. The loosening, re-protrusion and the union of graft bone was judged by X-ray. Results The mean follow-up was 46.5 months (19-152 months). One patient developed DVT on the second day post-operatively who recovered well after anticoagulation treatment. One patient complained of gentle thigh pain which disappeared at 6 months. No other complication was found. The mean Harris scores had improved from 48.9±6.5 pre-operatively to 91.2±5.7 post-operatively. All prostheses acquired bone stabilization with no sign of loosening and re-protrusion and the grafts bone were healed at a mean 6 months according to X-ray. Conclusion THA with acetabular bone grafting and cementless component for protrusio acetabuli have acquired excellent results and prevented loosening and re-protrusio effectively.
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Objective To observe the effect of lnng-term in vitro culture on the biological properties of adipose-derived stem cells(ADSCs)as seeding cells of tissue engineering.Methods The surface makers and apoptosis of primary and passaged human ADSCs were identified by flow cytometric analysis.Osteogenic differentiation of ADSCs at different passages were identified by alkaline phosphatase(ALP),Von Kossa staining and RT-PCR respectively.Results The surface marker expression of mesenchymal stem cells on ADSCs was high and did not change with passages of the cells.The early apoptosis rate of the cells was 1% to 2%,and increased insignificantly from passage one to passage nine.The osteogenic potential of ADSCs confirmed by ALP,Von Kossa staining and RT-PCR was maintained to as late as passage eight.Conclusion Since the biological properties of ADSCs are stable,they can be served as optimal seeding cells for tissue engineering and regenerative research.
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0.05). But when the flexion exceeded 30?, especially when it exceeded 60?, the displacement in pPc increased markedly, much greater than that of an intact knee (P0.05), while a slight over-restriction may be found at some angles. Conclusion Double-band reconstruction could effectively restrict the posterior displacement of the tibia and restore anteroposterior stability to the knee joint within its full range of flexion. aPc reconstruction could also maintain the posterior stability of the knee, while the result of pPc reconstruction is most unsatisfactory.