Xiaochun Peng

Does computer-assisted surgery improve postoperative leg alignment and implant positioning following total knee arthroplasty? A meta-analysis of randomized controlled trials?

PurposeComputer-assisted surgery has been proposed as a technique to improve implant alignment during total knee arthroplasty (TKA). However, there is still a debate over the accuracy of placing the femoral and tibial components using computer-assisted systems in TKA. The aim of this study is to establish whether computer-assisted surgery leads to superior mechanical leg axis and implant positioning than conventional technique in patients with primary TKA.MethodsMajor electronic databases were systematically searched to identify relevant studies without language restriction. A meta-analysis of 41 randomized controlled trials (RCTs) or quasi-RCTs was performed in a random effects model. A subgroup analysis was conducted by type of navigation system to explore the clinical heterogeneity between these trials. The following radiographic parameters were used to compare computer-assisted surgery with conventional technique: (1) mechanical leg axis, (2) femoral component coronal alignment, (3) tibial component coronal alignment, (4) femoral component sagittal alignment, and (5) tibial component sagittal alignment.ResultsFor the mechanical leg axis and coronal positioning of femoral and tibial components, there are statistically significant reductions in the number of patients with malalignment in the CAS group if the outlier cutoff value is ±3 or 2° in the coronal and sagittal planes, respectively. Subgroup analysis demonstrates that CT-free navigation systems provide better alignment than conventional techniques in the coronal and sagittal alignment of femoral components within ±3 and 2°. If the outlier cutoff value for the tibial sagittal alignment is ±2°, the outlier percentages are higher in the CT-free navigation group than in the conventional group. However, there was no significant difference in the tibial sagittal alignment at ±3°.ConclusionComputer-assisted surgery does improve mechanical leg axis and component orientation in TKAs. However, high-quality RCTs are necessary to determine whether surgeons could use computer-assisted techniques to achieve a targeted tibial slope in TKA.Level of evidenceTherapeutic study (Systematic review of Level I/II studies), Level II.

A Systematic Review and Meta-Analysis of Antibiotic-Impregnated Bone Cement Use in Primary Total Hip or Knee Arthroplasty

Background Antibiotic-impregnated bone cement (AIBC) has been widely used for the treatment of infected revision arthroplasty, but its routine use in primary total joint arthroplasty (TJA) remains considerably controversial. With this meta-analysis of published randomized controlled trials, we intended to assess the antimicrobial efficacy and safety of AIBC for its prophylactic use in primary TJA. Methods A literature search was performed in MEDLINE, Embase, CBMdisc and the Cochrane Library until June, 2013. The studies were divided into two sub-groups according to the type of the control group. Outcomes of interest included postoperative infection rates, radiographic outcomes and clinical joint score. Study quality was evaluated using the Jadad scale (five points). Results In total, eight studies were included, with a sample size of 6,381 arthroplasties. The overall pooled data demonstrated that, compared with the control (plain cement or systemic antibiotic), AIBC did not reveal an advantage in decreasing the rate of superficial infection (relative risk [RR] = 1.47; 95% CI, 1.13–1.91; P=0.004), while there were significant differences in deep infection rate between the AIBC and control group (RR = 0.41; 95% CI, 0.17–0.97; P=0.04). For the analysis of gentamicin and cefuroxime subgroups, the gentamicin was superior to the cefuroxime in reducing deep infection rate (P=0.0005 versus P= 0.10). However, no significant differences were found in their radiographic outcomes and clinical joint score. Conclusion This meta-analysis had proven that the prophylactic use of AIBC could lower the deep infection rate in primary TJA, while AIBC did not show an improvement in reducing the superficial infection rate compared with the control. More sufficiently powered studies would be required to further evaluate the efficacy and safety of AIBC for primary TJA.

A novel open-porous magnesium scaffold with controllable microstructures and properties for bone regeneration

The traditional production methods of porous magnesium scaffolds are difficult to accurately control the pore morphologies and simultaneously obtain appropriate mechanical properties. In this work, two open-porous magnesium scaffolds with different pore size but in the nearly same porosity are successfully fabricated with high-purity Mg ingots through the titanium wire space holder (TWSH) method. The porosity and pore size can be easily, precisely and individually controlled, as well as the mechanical properties also can be regulated to be within the range of human cancellous bone by changing the orientation of pores without sacrifice the requisite porous structures. In vitro cell tests indicate that the scaffolds have good cytocompatibility and osteoblastic differentiation properties. In vivo findings demonstrate that both scaffolds exhibit acceptable inflammatory responses and can be almost fully degraded and replaced by newly formed bone. More importantly, under the same porosity, the scaffolds with larger pore size can promote early vascularization and up-regulate collagen type 1 and OPN expression, leading to higher bone mass and more mature bone formation. In conclusion, a new method is introduced to develop an open-porous magnesium scaffold with controllable microstructures and mechanical properties, which has great potential clinical application for bone reconstruction in the future.

Calcium Plasma Implanted Titanium Surface with Hierarchical Microstructure for Improving the Bone Formation

Introducing hierarchical microstructure and bioactive trace elements simultaneously onto the surface of titanium implant is a very effective way to improve the osseointegration between bone and implant. In this work, hierarchical topography was prepared on Ti surface via acid etching and sandblasting (SLA) to form micropits and microcavities then underwent Ca plasma immersion ion implantation (Ca-PIII) process. The surface wettability and roughness did not change obviously before and after Ca-PIII process. The in vitro evaluations including cell adhesion, activity, alkaline phosphatase (ALP), osteogenic genes (Runx2, OSX, ALP, BSP, Col1a1, OPN, and OC), and protein (BSP, Col1a1, OPN, and OC) expressions revealed that the introduction of Ca ions onto the surface of SLA-treated Ti can promote greater osteoblasts adhesion, spread and proliferation, which in return further accelerated the maturation and mineralization of osteoblasts. More importantly, in vivo evaluations including Micro-CT evaluation, histological observations, push-out test, sequential fluorescent labeling and histological observations verified that Ca-SLA-treated Ti implants could efficiently promote new bone formation in early times. These promising results suggest that Ca-SLA-treated Ti has the potential for future application in orthopedic field.

Balancing the Osteogenic and Antibacterial Properties of Titanium by Codoping of Mg and Ag: An in Vitro and in Vivo Study

To simultaneously enhance the osteogenic and antibacterial properties of titanium, we introduced magnesium (Mg), silver (Ag), or both by using the plasma immersion ion implantation (PIII) technique, producing three PIII sample groups, namely, Mg-doped titanium (Mg-PIII), Ag-doped titanium (Ag-PIII), and Mg and Ag codoped titanium (Mg/Ag-PIII). The in vitro antibacterial efficacy of Mg/Ag-PIII group was about 7-10% higher than that of Ag-PIII. In vitro and in vivo results demonstrated that osteogenic property of Mg/Ag PIII group was better than that of Ag-PIII or Mg-PIII. It was believed that the galvanic effects between Mg and Ag NPs played a key role in facilitating the release of Mg but reducing the release of silver, answering for the selective performances of the Mg/Ag-PIII group over bacterial and mammalian cells. This study demonstrated that the integration of multiple functional elements could be realized by the dual-source PIII technique, and in this case, the antibacterial properties and osteogenic property of titanium could be balanced.

Efficient Inhibition of wear debris-induced inflammation by locally delivered siRNA.

Aseptic loosening is the most common long-term complication of total joint replacement, which is associated with the generation of wear debris. The purpose of this study was to investigate the inhibitory effect of small interfering RNA (siRNA) targeting tumor necrosis factor-alpha (TNF-alpha) on wear debris-induced inflammation. A local delivery of lentivirus-mediated TNF-alpha siRNA into the modified murine air pouch, which was stimulated by polymethylmethacrylate (PMMA) particles, resulted in significant blockage of TNF-alpha both in mRNA and protein levels for up to 4 weeks. In addition, significant down-regulation of interleukin-1 (IL-1) and interleukin-6 (IL-6) was observed in TNF-alpha siRNA-treated pouches. The safety profile of gene therapy was proven by Bioluminescent assay and quantitative fluorescent flux. Histological analysis revealed less inflammatory responses (thinner pouch membrane and decreased cellular infiltration) in TNF-alpha siRNA-treated pouches. These findings suggest that local delivery of TNF-alpha siRNA might be an excellent therapeutic candidate to inhibit particle-induced inflammation.

No clinical benefit of gender-specific total knee arthroplasty

Background and purpose— There is no consensus regarding the clinical relevance of gender-specific prostheses in total knee arthroplasty (TKA). We summarize the current best evidence in a comparison of clinical and radiographic outcomes between gender-specific prostheses and standard unisex prostheses in female patients. Methods— We used the PubMed, Embase, Cochrane, Science Citation Index, and Scopus databases. We included randomized controlled trials published up to January 2013 that compared gender-specific prostheses with standard unisex prostheses in female patients who underwent primary TKAs. Results— 6 trials involving 423 patients with 846 knee joints met the inclusion criteria. No statistically significant differences were observed between the 2 designs regarding pain, range of motion (ROM), knee scores, satisfaction, preference, complications, and radiographic results. The gender-specific design (Gender Solutions; Zimmer Inc, Warsaw, Indiana) reduced the prevalence of overhang. However, it had less overall coverage of the femoral condyles compared to the unisex group. In fact, the femoral prosthesis in the standard unisex group matched better than that in the gender-specific group. Interpretation— Gender-specific prostheses do not appear to confer any benefit in terms of clinician- and patient-reported outcomes for the female knee.

Soluble P selectin in synovial fluid level is correlated with the radiographic severity of knee osteoarthritis

BACKGROUND Recent studies provide evidence that inflammation is a feature of the disease process in Osteoarthritis (OA). The clinical significance of P selectin (Ps) in OA has not been adequately studied and the association between Ps level and OA severity remains unknown. METHODS We enrolled 120 knee OA subjects and 45 controls. All patients were scored for Kellgren-Lawrence grade (0-4). The Ps in serum and synovial fluid (SF) as well as serum C-reactive protein (CRP) levels were detected. RESULTS The mean Ps level in OA subjects was markedly increased than that in controls. In OA patients, the SF Ps levels increased with the severity of KL scores and significantly correlated with severity of disease (r=0.546, P<0.001) and serum CRP level (r=0.488, P<0.001). However, the serum Ps level did not show a significant correlation with the severity of OA. CONCLUSION The Ps levels in SF were significantly correlated with the severity of OA, suggesting that it may be used as a biomarker to evaluate the progression of OA.

Comparison of the quadriceps-sparing and subvastus approaches versus the standard parapatellar approach in total knee arthroplasty: a meta-analysis of randomized controlled trials

BackgroundThe quadriceps-sparing and subvastus approaches are two of the most commonly used minimally-invasive approaches in total knee arthroplasty (TKA). However, the conclusion among studies still remains controversial. The purpose of this meta-analysis was to compare the clinical efficacy of the subvastus and quadriceps-sparing approaches with the standard parapatellar approach in TKA.MethodsRandomized controlled trials (RCTs) comparing the quadriceps-sparing or subvastus approach with the standard parapatellar approach was identified in the databases of PubMed, the Cochrane library, EMBASE and Web of Science up to July 2014. Two authors extracted the following data: the basic characteristics of patients, the methodological quality and clinical outcomes from the included RCTs independently. RevMan 5.2.7 software was used for meta-analysis.ResultsA total of 19 RCTs (1578 patients) were included for meta-analysis. The results suggested that the quadriceps-sparing approach showed better outcomes in knee society score (KSS) and visual analog score (VAS), but this approach required a longer operative time than the standard parapatellar approach. There were no differences in total complications, wound infection, deep vein thrombosis, blood loss and hospital stay between the quadriceps-sparing and standard approaches. The subvastus approach showed better outcomes in VAS, knee range of motion (ROM), straight leg raise and lateral retinacular release than the standard parapatellar approach. There were no differences in KSS, total complication, wound infection, deep vein thrombosis, blood loss and hospital stay between the quadriceps-sparing and standard approaches.ConclusionsThe current evidence showed that, when compared with the standard parapatellar approach, the quadriceps-sparing approach was associated with better outcomes in KSS and VAS but required a longer operative time, and the subvastus approach was associated with better outcomes in VAS, ROM, straight leg raise and lateral retinacular release.

Up-regulated expression of MIF by interfacial membrane fibroblasts and macrophages around aseptically loosened implants.

BACKGROUND Local chronic inflammatory reaction plays an important role in the process of aseptic loosening of implants after total joint replacement. In addition, macrophage migration inhibitory factor (MIF) is a key upstream regulator of inflammation, and it is a significant regulator of inflammatory diseases. The purpose of this study is to investigate if the fibroblasts and macrophages in the interfacial membranes overexpress MIF. MATERIALS AND METHODS The 15 tissue samples of interfacial membranes were obtained from the tissues around the aseptically loosened femoral implants adjacent to osteolytic lesion in 15 patients. The 15 control synovial samples of hip joints were obtained from 15 patients who underwent primary hip arthroplasty because of the fresh fracture of the femoral neck. The levels of MIF protein and mRNA were evaluated by ELISA assay, immunofluorescence labeling, and real-time RT-PCR. Fibroblasts and macrophages were identified by immunofluorescence labeling. RESULTS The levels of MIF protein and mRNA were significantly increased, as well as the numbers of MIF+ fibroblasts and macrophages in the interfacial membranes compared with the control synovium. CONCLUSION Not only the macrophages, but also the fibroblasts in interfacial membranes overexpress MIF. MIF may play a significant role in the process of aseptic-loosening implants after total joint replacement.