Subtrochanteric shortening osteotomy during cementless total hip arthroplasty in young patients with severe developmental dysplasia of the hip.

BACKGROUND: This retrospective study was designed to determine complications, functional and radiographic results of transverse subtrochanteric osteotomy during cementless, modular total hip arthroplasty (THA) in a series of active patients younger than 45 years with Crowe Type-III or IV developmental dysplasia of the hip (DDH). METHODS: We followed 49 patients (56 hips) with DDH who were treated with cementless THA, where the acetabular cup was positioned in the anatomic hip center and where a simultaneous transverse femoral osteotomy was performed. Complication rate evaluation and clinical outcomes were measured by validated clinical scores and radiographic evaluation were performed at a mean follow up of 10 years (range, 4.8-14.3 years). RESULTS: The mean limb-length discrepancy was reduced from 4.2 cm to 1.1 cm (P < 0.01). The mean Harris hip score (HSS) significantly improved from 40.6 points to 87.4 points (P < 0.01). Similarly, severity of low back pain, modified MAP, HOOS, and SF-12 also showed significant improvement (P < 0.01). There were 3 cases of postoperative dislocation, 3 cases of transient nerve palsy, 2 cases of nonunion, and 4 cases of intraoperative fracture. At 10 years follow-up, the estimated survival rate with any component revision as end points was 92%. CONCLUSION: The cementless THA combined with transverse subtrochanteric osteotomy is a reliable technique with restoration of a more normal limb, satisfactory clinical outcomes, and mid-term survival of components.

Preparation of electrospun PLGA-silk fibroin nanofibers-based nerve conduits and evaluation in vivo.

With advances in technical methodology, the grafting of biocompatible conduits may become a viable alternative for the reconstruction of nerve gaps. In this study, electrospinning was used to fabricate nerve conduits (NCs) from poly(L-lactide-coglycolide)-silk fibroin. Conduits or autograft nerves were employed to bridge 10 mm defects in the sciatic nerves of Sprague-Dawley rats. Six weeks after the operation, morphological and functional assessment showed that nerve conduits from PLGA-silk fibroin grafts promoted the regeneration of peripheral nerves. The effects were similar to those obtained using nerve autografts. This method offers a promising alternative to the use of nerve autografts.

[Application of n-HA/PA66 composite artificial vertebral body in anterior reconstruction of lower cervical spine fracture and dislocation].

OBJECTIVE: To initially evaluate the application of artificial vertebra of n-HA/PA66 in anterior reconstruction of lower cervical spine fracture and dislocation. METHODS: In this study, 84 patients with lower cervical spine fracture and dislocation received anterior cervical discectomy, spinal canal decompression or subtotal corpectomy, spinal canal decompression and reconstruction by n-HA/PA66 composite artificial vertebral body combined with plate instrumentation. Neurological function was followed up by improvement rate of Frankel and situations of the supporting body was observed by X ray and 3D-CT in 3, 12, 24 months postoperatively. The intervertebral height, physical arc (reflected by Cobb angle) and the locations and fusion rate of the supporting body were assessed in order to evaluate the stability of the cervical spine and alignment improvements. RESULTS: All the patients underwent operation successfully and were followed up for 6 to 24 months with an average of 12 months. The preoperative symptoms were improved to varying degrees. Imaging studies showed that in all cases graft fusion were achieved, and cervical alignments, intervertebral height, cervical spine stability and the locations of the artificial vertebral body were well maintained. No displacement and subsidence of the artificial vertebral body occurred. Postoperative immediate intervertebral height (2.4 ± 0.2) cm, preoperative intervertebral height (1.9 ± 0.1) cm, comparisons of the two groups was statistically significant (q = 2.48, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group intervertebral height was not statistically significant (P > 0.05). Preoperative Cobb angle was 9.8° ± 1.2°, postoperative immediate Cobb angle was 16.6° ± 1.2°, comparisons of the two groups was statistically significant (q = 14.25, P < 0.001). The immediate, 3 month, 1 year, 2 year period follow-up group Cobb angle was not statistically significant (P > 0.05). CONCLUSIONS: n-HA/PA66 artificial vertebral body can provide early cervical spine support and stability and effectively maintain the biological alignment and cervical intervertebral height. It has high rate of graft fusion and is convenient to observe by X-ray. Therefore, n-HA/PA66 can be taken as an ideal graft for anterior lower cervical spine fracture and dislocation operation, but further follow-up study is still required to evaluate the long-term effects.

[Repairing bone defect with nano-hydroxyapatite and polyamide 66 composite after giant cell tumor operations].

OBJECTIVE: To evaluate the clinical effectiveness and safety of using granular type nano-hydroxyapatite and polyamide 66 (n-HA/PA66) composite in repairing bone defects caused by giant cell tumors. METHODS: 48 patients with giant cell tumors, who underwent lesion curettage, inactivation and cavities fill-in with granular type n-HA/PA66 from December 2007 to May 2011, were followed up. Routine blood tests, liver and kidney functions, serum calcium and phosphorus, and immunologic parameters were examined before and after the surgeries. Radiological examinations were carried out 1 week and 1, 3, 6 and 12 months post operations to monitor the bone repairing process. The n-HA/ PA66 in bone issues was detected with hematoxylin-eosin staining. RESULTS: 45 patients completed the follow-up. No significant abnormalities in routine blood tests, serum calcium and phosphorus, and immunologic parameters were found pre- and post-operations. Nor abnormal liver and kidney functional lesions were identified. The radiological examination showed gradual increase in the density of the focal zone after bone implanting operations. The bone density of the implanted areas got close to normal 1 year after operations. The histological examination found that osteoblasts grew into the hole of n-HA/PA66; calcium was deposited on the materials; and large amount of osteocytes inlaid into the composite. The composite was integrated into new bone and surrounding tissues. CONCLUSION: n-HA/PA66 has good biocompatibility and biological safety. It also has good osteoconduction and osteogenesis activity. The n-HA/PA66 composite is one perfect bone repair material.

[Histological and biomechanical study of repairing rabbit radius segmental bone defect with porous titanium].

OBJECTIVE: To investigate the therapeutic effects of porous titanium (Ti) on the recovery of rabbit radial bone defect. METHODS: Bone defects were artificially made in 30 New Zealand rabbits by resecting the 1 cm substantial osseo with periosteum of both radii. The left anterior limbs were implanted with porous titanium, while the right anterior limbs with porous hydroxyapatite (HA). The rabbits were sacrificed at three time points. Both the radii healing statuses were observed by histology and histomorphometry analyses by means of computer graphic processing at the end of 8, 12 and 24 weeks, and biomechanical analyses at the end of 12 and 24 weeks. RESULTS: The histology examination showed that mass newly formed bone had grown into most pores of both the specimens. Along with prolongation of times after operation, the ingrowths of bone cells and effects of bone remodeling in the research side were nearly the same as those in the control side at the end of 12 and 24 weeks. The interface between the new bone and implants showed tight contact in both the groups without an obvious fibrous tissue. The results of histomorphometrical analyses showed that a statistically significant difference was not obtained for % bone area (bone area/ gross implant) between both the groups (P>0.05).However, the results of maximum failure load for the Ti group and the HA group were (107.34±27.44) N and (93.42±21.18) N at the end of 12 weeks, (118.56±24.65) N and (102.15±23.37) N at the end of 24 weeks, respectively. Biomechanical properties of the Ti group was stronger than that of the HA group, however, a statistically significant difference was not obtained between both the groups (P=0.102). CONCLUSION: Porous titanium scaffold can promote the formation of new bone, which contributes to the healing of long tubular bone defect. The porous titanium can enhance the bone repairing effect on segmental bone defect nearly the same as porous hydroxyapatite .

[Cortical windowing of the femoral diaphysis for cement/plug removal in hip revision surgery].

OBJECTIVE: To analyze the results of cortical windowing of the femoral diaphysis for well-fixed cement/plug removal during hip revision surgery. METHODS: From May 2005 to June 2009, 14 patients (14 hips) were undergone revision total hip arthroplasty (THA), window was cut into the cortex of the femur, and the well-fixed cement/plug distal to the window was removed under the direct vision. After reimplanted the cementless revision stem, the cortical lids were replanted and fixed with 2 to 3 cerclage wires. Six patients who had suffered from osteoporosis were undergone morselized bone graft to the osteotomy site. Postoperatively, the patients were maintained at partial weight-bearing (touchdown) for 6 weeks and then advanced as they were able. RESULTS: The length of the cortical windows varied from 2.5 to 6.0 cm (mean, 3.4 cm), the width ranged from 0.8 to 1.4 cm (mean, 1.2 cm). In one patient the window was enlarged during the procedure to facilitate the cement/plug removal. The mean radiologically healing time for the windows was 19 weeks. There was no intraoperative femoral perforation during cement/plug removal. One femoral fracture during the revision stem was implanted. No postoperative periprosthetic fracture and other complications such as infection, implant subsidence occurred during the fellow-up. There was no femoral thigh pain or implant loosening with femoral window. CONCLUSION: The cortical windowing technique is very helpful to facilitate the well-fixed cement/plug distal to the prosthesis tip removal and the windows heal rapidly and decrease the femoral complications associated with revision THA.

Total hip arthroplasty with a cementless acetabular component and a cemented femoral component in the treatment of Chinese patients with femoral head necrosis.

The purpose of this study was to evaluate midterm clinical and radiographic outcomes associated with hybrid total hip arthroplasty in a consecutive series of 86 Chinese patients (93 hips) with osteonecrosis of the femoral head, which revealed that the mean Harris hip score increased from 39 +/- 6.0 points before operation to 90.4 +/- 4.6 points at the latest follow-up. There was pelvic osteolysis in one hip (1%), which required revision, and some small focal areas of femoral osteolysis in 12 hips (13%) were observed. The mean linear wear rate was 0.143 +/- 0.05 mm/y (0.02-0.45 mm/y). No loosening of the components was observed radiographically. The survival rate of the acetabular and femoral components for revision was 98% (95% confidence interval, 0.96-1.0) and 100% (95% confidence interval, 0.95-1.0). Hybrid total hip arthroplasty in patients with osteonecrosis of the femoral head had a satisfactory clinical and radiographic outcome at a minimum 5 years of follow-up. Because polyethylene wear and osteolysis cannot be avoided, the long-term effect should be further studied.

[Initial immunoreaction study on PVA/n-HA + PA66 biological composite material after being implanted into animal body].

OBJECTIVE: To observe immunoreaction to PVA/n-HA+ PA66 biological composite material after being implanted into animal body. METHODS: PVA/n-HA+PA66 composite materials were implanted into mouse subcutaneous tissue. Histologial examination was performed at 2, 4, 6 weeks, the amount of CD3, CD4+, CD8+ in blood and IL-1, IL-6, TNF-alpha in spleen cells was measured at the same time. RESULTS: The amount of CD3, CD4+, CD8+ in mouse blood and IL-1, IL-6, TNF-alpha in mouse spleen cells were not different with the control groups at 2, 4, 6 weeks (P > 0.05). The fibrous tissue and some blood vessels were found growing into the porous materials, which resulted in composite materials intergration of proliferative structure. The reject reaction was not found. CONCLUSION: PVA/n-HA+PA66 biological composite material does not cause immune rejection after being implanted into animal body, verifying its good biocompatibility.

[Reconstruction of acetabular defect with wire mesh and impacted bone graft in cemented acetabular revision].

OBJECTIVE: To discuss the method of reconstruction of acetabular bone defect with wire mesh, impaction bone-grafting and a cemented cup in acetabular component revision. METHODS: 21 hips in 21 patients, aged 50.1 (31 - 64), 2 hips being of the acetabular defect type I B, 1 hip of type II A, 4 hips of type II B, and 14 hips of type III according to the American Academy of Orthopaedic Surgeons (AAOS) grading system underwent reconstruction with wire mesh, impacted bone grafts and cemented polyethylene acetabular component, and then were followed up for 47 months (36 - 60 months). RESULTS: The mean Harris hip score improved from the preoperative 55.7 points to 92.9 points at the last time of follow-up. Radiographic incorporation between host the bone and allograft was achieved 11.4 months after the operation on average. The mean change of inclination of acetabular components was 2.2 degrees , in which one acetabular component developed a change of 15.5 degrees . The inclination of acetabular components increased by 1.7 degrees on average 3 months after the operation and 2.0 degrees 6 months after the surgery. The acetabular cup migrated medially and superiorly by 3.93 mm and 4.41 mm respectively, peaking in the sixth month after the operation. One hip developed heterotopic ossification (Brooker grade I). One hip received repeat revision because of the aseptic loosening of the acetabular component 25 months after the revision surgery. CONCLUSION: The changes of the position of acetabular cup mainly occur within six months after the reconstruction of severe acetabular bone defect with wire mesh, impacted bone graft and cemented polyethylene acetabular component. To prevent the displacement of the acetabular cup, it is necessary to keep initial stability of the acetabular cups within six months after the index surgery.

[Three-dimensional finite element analysis responsible to bone cement with customized prosthesis of proximal segmental femur].

OBJECTIVES: To create three-dimensional finite element models for the large defect of proximal femur and the customized prosthesis of proximal segmental defect femur, and to analyze the influence on the stress distribution of femur-cement after the intramedullary implantation of different stem length prostheses. METHODS: Three-dimensional finite element models were established for the large defect of proximal femur and proximal femoral segmental prostheses with different stem-lengths (140 mm, 120 mm, 100 mm, 80 mm and 60 mm). The influence on stress distribution of femur-cement was analyzed for the different stem-length prostheses implanted. RESULTS: The stress on bone cement gradually increased from proximal end to distal end, and reached its highest value near the tip of prostheses. The prostheses with stem lengths of 120 mm, 100 mm, 80 mm and 60 mm could bring the cement mantle stress to the value beyond the fatigue strength of cement. Only when the intramedullary stem-length of prosthesis was 140 mm, the stress on the cement mantle was under the fatigue strength of cement. CONCLUSION: The intramedullary stem of the proximal femoral segmental prosthesis must have enough length to decrease the stress on the cement mantle in order to avoid the prosthesis loosening.

Short-term survival analysis of the all-polyethylene tibial component in total knee arthroplasty.

OBJECTIVE: To report the clinical and radiological results of 24 total knee arthroplasty in which all-polyethylene tibial components were used. METHODS: Between December 2000 and December 2002, 24 cemented total knee arthroplasty in 21 patients were performed using all-polyethylene tibial components. The mean age of the 21 patients (9 men and 12 women) at operation was 55 years, ranging 48-61 years. The mean preoperative hospital for special surgery (HSS) score was 40.2 (range, 36-43). The diagnoses were degenerative osteoarthritis in 15 patients, rheumatoid arthritis in 5 and traumatic arthritis in 1. All the operations were performed by the same surgeon group and there were unilateral operations in 18 patients and bilateral operations in 3. RESULTS: Eighteen patients were followed up with a follow-up rate of 85.7%. The mean follow-up is 2.5 years (range, 1-3 years) and mean postoperative HSS scores was 87.5 (range, 83-89). Among them, 18 were excellent, 3 good, 3 poor and none was fair (the results of three lost patients were classified as poor). Of those reviewed, the prosthesis was all in situ and no revision occurred. Radiological assessment of these patients revealed 4 (16.67%) tibial components with radiolucent lines (mean width < or = 2 mm) distributed mainly in zone 1 and zone 4. None of these knees was symptomatic. CONCLUSIONS: The result of total knee arthroplasty using all-polyethylene tibial components is encouraging. The operative techniques are similar to those in arthroplasty using metal-backed tibial component.

Radiographic and clinical analysis of cementless acetabular fixation in total hip arthroplasty.

OBJECTIVE: To investigate the factors affecting the fixation, loosening and therapeutic effect of cementless acetabular prosthesis through following up the patients with total hip arthroplasty clinically and radiographically. METHODS: From February 1998 to May 1999, 139 patients (148 hips) underwent total hip arthroplasty with cementless acetabular prosthesis in our department. In this study, the clinical therapeutic effect and the anteroposterior radiographs of the pelvis and anteroposterior and lateral radiographs of the hips of 109 patients (116 hips) made before operation, at 1 week, 3, 6, and 12 months after operation and annually thereafter were analyzed retrospectively. The clinical therapeutic effects were evaluated with Harris hip score. Radiographs were used to observe the position of prostheses and the bone changes around the implant, and to measure the wearing speed and direction of the acetabular cup. All evaluations were made by an independent examiner who did not participate in the operation. The patients were followed up for 5-6 years. RESULTS: The mean Harris score was 44 points (range, 10-70 points) before operation, but it increased to 92.4 points (range, 80-100 points) at the latest review after operation, which was significantly higher than that before operation (P<0.05). No acetabular component was revised because of infection or aseptic loosening. And no acetabular component migrated. There was no revision of fixed acetabular component because of pelvic osteolysis secondary to polyethylene wear. The mean linear wear rate was 0.15 mm per year. All the acetabular prostheses were classified as stable on the radiographs. CONCLUSIONS: In terms of fixation, total hip arthroplasty with cementless acetabular components was successful. Although there is no aseptic loosening and a low incidence of osteolysis at the latest follow-up evaluation, polyethylene wear cannot be avoided and can lead to expansile osteolysis near the cups. This kind of osteolysis usually had no obvious clinical symptoms but it can be diagnosed early on radiographs. So radiographical follow-up for cementless acetabular components is very important.

Octyl-a-cyanoacrylate adhesive in the treatment of tibial transverse fracture in rabbits.

OBJECTIVE: To observe the effect of octyl-a-cyanoacrylate upon bone healing and its degradation in vitro after middle tibial transverse fracture in rabbitsì and to establish treatment of higher efficacy with the application of octyl-a-cyanoacrylate. METHODS: Middle tibial transverse fracture model of New Zealand rabbits was established. In the experimental group, internal fixation with 2 mm Kirschner wires was performed and the broken ends were fixed with octyl-a-cyanoacrylate. In the control group, only internal fixation with 2 mm Kirschner wires was conducted. Animals were killed at preset time intervals of 2, 4, 6, 8, 10 and 12 weeks postoperatively and samples were harvested. RESULTS: Two weeks after operation, clear fracture lines were observed in both the experimental and the control groups. Fibrous soft tissue connection was noted between the broken ends and there was soft tissue adhesion around the fracture site. There was no callus formation and the broken ends were surrounded by adhesive soft tissues. Obvious external callus formation was confirmed at 8 weeks after operation in both groups with partial disappearance of fracture lines. Ten and twelve weeks after the operation, fracture lines disappeared completely and there was obvious external callus formation and bone union. In the fourth week, fibrous cells and chondrocytes were found to grow into the colloid and surround it at the 6th week. The adhesive material was degraded and gradually absorbed at the 8th week. Chondrification was observed. CONCLUSIONS: Two weeks after fixation for tibial fracture in rabbits, octyl-a-cyanoacrylate begins in vivo degradation. Chondrocytes and fibrocytes gradually grow into the degradation area and surround the adhesive material, which broke into pieces at 8 weeks. Complete degradation and disappearance of the adhesive material is present between 10 and 12 weeks. No barrier effect hampering fracture healing is noted.

[Effect of controlled release microspheres incorporating bFGF on Schwann cells].

OBJECTIVE: To investigate the effects of controlled release microspheres (Ms) incorporating bFGF on the cultured Schwann cells. METHODS: The secondary cultured Schwann cells were divided into three groups according to the different ingredients being added to the DMEM culture medium: bFGF group, and bFGF-PLGA-Ms group, and bFGF-PELA-Ms group. At different times after culture, the proliferative Schwann cells were collected from three groups individually. Then the number of Schwann cells was measured with cell counting method, the viability of Schwann cells was measured with MTT method and the cell cycle of Schwann cells was measured with flow cytometry. RESULTS: The in vitro cellular study showed that 1, 2 days after plate culture, the number of cells and the cell viability of bFGF group were significantly larger than those of bFGF-PLGA-Ms group and bFGF-PELA-Ms group. 3, 4 days after plate culture, the number of cells and the cell viability of bFGF group and bFGF-PLGA-Ms group were significantly larger than those of bFGF-PELA-Ms group. 6, 8 days after plate culture, the number of cells and the cell viability of bFGF-PLGA-Ms group was significantly larger than those of bFGF group and bFGF-PELA-Ms group. For the flow cytometry examination, 2 days after plate culture, the G2/ M+S percentage of bFGF group was the highest, and 4, 8 days after plate culture, the G2/M+S percentage of bFGF-PLGA-Ms group was the highest. CONCLUSION: Free bFGF can promote the proliferation of Schwann cells in a short period, while bFGF-PLGA-Ms can promote the proliferation of Schwann cells in a long period because of the controlled release of bFGF from microspheres. bFGF-PELA-Ms meets the property requirement of controlled release, but the biological activity of released bFGF is destroyed partially.

Is a ceramic-on-ceramic bearing really superior to ceramic-on-polyethylene for primary total hip arthroplasty? A systematic review and meta-analysis of randomised controlled trials.

INTRODUCTION: The outcomes of using a ceramic-on-ceramic (CoC) vs ceramic-on-polyethylene (CoP) bearing surface for primary total hip arthroplasty (THA) are much debated. We performed a systematic review and meta-analysis of randomised controlled trials (RCTs) to compare and evaluate the outcomes of these 2 bearing surfaces. MATERIALS AND METHODS: Electronic databases (PubMed/Medline, CENTRAL, Embase and Web of Science) were systematically searched for RCTs investigating the association between bearing surfaces and outcomes following primary THA. Two investigators independently reviewed studies for eligibility, assessed the risk of bias, extracted and analysed the data. RESULTS: In total, 13 RCTs including a total of 2,488 THAs were identified. The Harris Hip Score appeared to be similar between CoC and CoP THAs. The acetabular liner wear rate was lower in CoC than CoP THA, but the meta-analysis showed that the incidence of component-related noise and overall ceramic fracture in CoC group were 14.73 times and 6.02 times higher than CoP THA, respectively. There were no statistically significant differences in rates of radiolucent line formation (>1 mm), osteolysis, loosening, revision with follow-up ≥ 5 years, intraoperative femoral fracture, dislocation, deep infection, deep venous thrombosis and leg length discrepancy between CoC and CoP THAs. CONCLUSIONS: There appears to be no clear evidence favouring the use of either a CoC or CoP bearing surfaces in primary THA, further studies with high-quality and longer term follow-up to provide more evidence on this topic are still required.

Experimental study on the adhesion, migration and three-dimensional growth of Schwann cells on absorbable biological materials.

OBJECTIVE: To study the adhesion, migration and three-dimentional growth of Schwann cells on PLA (polylactic acid) nonspinning fibre cloth and polyglycolic/polylactic acid (PLGA) fibres. METHODS: Schwann cells/ECM gel solution and PLA nonspinning fibre cloth and PLGA fibres pretreated by collagen, polylysine and ECM were co-cultured. Then the migration and three-dimensional growth of Schwann cells on the fibres were observed under phase contrast microscope and laser scanning confocal microscope. RESULTS: Schwann cell/ECM solution was compounded with PLA nonspinning fibre cloth. With formation of gel, most Schwann cells resided in the fibre net holes, and adhered to the fibres to form a multiplayer-arranged Schwann cell column like Büngner band. Schwann cells could adhere to PLGA fibres and grew and migrated along the fibres. ECM gel could significantly increase the adhering and migrating cell number. CONCLUSIONS: ECM gel can facilitate the adhesion, growth and migration of Schwann cells on the seteroframe. It is a good integrating material for tissue engineering bioartificial nerve.

Extensively coated non-modular stem used in two-stage revision for infected total hip arthroplasty: mid-term to long-term follow-up.

OBJECTIVE: To determine the rate of curing the infection and mid- to long-term outcomes of using extensively coated non-modular stems in two-stage revision for infected total hip arthroplasty (THA). METHODS: The clinical data of 33 patients (33 hips) in whom extensively coated non-modular stems had been used in two-stage revision THA for deep infection were retrospectively analyzed. All operations received two-stage reimplantation, which included resection arthroplasty, thorough debridement, insertion of a hand-molded antibiotic-impregnated cement spacer with stainless steel reinforcement, a course of intravenous antibiotics, and delayed reimplantation. Microorganism-specific antibiotics had been chosen according to the results of microbiological studies performed postoperatively. All patients received i.v. antimicrobial therapy for 4 weeks and oral antibiotics to which their organisms were sensitive for a further 6 weeks. Harris hip score (HHS) and plain X-ray films were used to perform clinical and radiological evaluations. RESULTS: During follow-up for a minimum of 5 years, no reinfection or loosening were found. Cultures of samples taken during the second stage were all negative for infection. The mean HHS improved from 42 preoperative to 89 at the final follow-up. All granular bones had fused well with the host bones by 12 months after the surgery. CONCLUSION: Using extensively coated non-modular stems combined with intramedullary allografts in two-stage revision for treating infected THAs can achieve satisfactory outcomes.