Silicon-Doped Titanium Dioxide Nanotubes Promoted Bone Formation on Titanium Implants.

While titanium (Ti) implants have been extensively used in orthopaedic and dental applications, the intrinsic bioinertness of untreated Ti surface usually results in insufficient osseointegration irrespective of the excellent biocompatibility and mechanical properties of it. In this study, we prepared surface modified Ti substrates in which silicon (Si) was doped into the titanium dioxide (TiO2) nanotubes on Ti surface using plasma immersion ion implantation (PIII) technology. Compared to TiO2 nanotubes and Ti alone, Si-doped TiO2 nanotubes significantly enhanced the expression of genes related to osteogenic differentiation, including Col-I, ALP, Runx2, OCN, and OPN, in mouse pre-osteoblastic MC3T3-E1 cells and deposition of mineral matrix. In vivo, the pull-out mechanical tests after two weeks of implantation in rat femur showed that Si-doped TiO2 nanotubes improved implant fixation strength by 18% and 54% compared to TiO2-NT and Ti implants, respectively. Together, findings from this study indicate that Si-doped TiO2 nanotubes promoted the osteogenic differentiation of osteoblastic cells and improved bone-Ti integration. Therefore, they may have considerable potential for the bioactive surface modification of Ti implants.

Adhesion of osteoblast-like cell on silicon-doped TiO2 film prepared by cathodic arc deposition.

Silicon-doped TiO2 (Si-TiO2) and pure TiO2 films were deposited on titanium substrates by cathodic arc deposition technique. The surface characteristics of the films, such as surface topography, elemental composition and wettability, were studied. About 4.6 % Si was incorporated into the Si-TiO2 films with a water contact angle of about 83°. The adhesive behaviors of osteoblast-like MG63 cells on both films were investigated through cell counting assay, immunocytochemistry, real-time PCR and western blotting analysis. Cells cultured on the Si-TiO2 films had a greater cellular viability, stronger cytoskeleton and focal adhesion, and more cellular spreading than those on the pure TiO2 films. Moreover, the expression levels of integrin ß1 and focal adhesion kinase (FAK) genes, FAK and the phosphorylation of FAK proteins were up-regulated in cells cultured on the Si-TiO2 films. These results indicated that the Si-TiO2 films possess significantly enhanced cytocompatibility and provide potential solutions for the surface modification of implants in the future.

Cementless distal fixation modular stem without reconstruction of femoral calcar for unstable intertrochanteric fracture in patients aged 75 years or more.

INTRODUCTION: Hemiarthroplasty (HA) using standard-length femoral stem with reconstruction of femoral calcar or using calcar replacing prosthesis for unstable intertrochanteric fractures in elderly patients is a viable option. However, both of the techniques increase the complexity of procedure, operative trauma and complication. This study evaluated the clinico-radiological results of the MP-Link cementless distal fixation modular prosthesis without reconstruction of femoral calcar for unstable intertrochanteric fracture in patients aged 75 years or more. HYPOTHESIS: Bipolar HA using the MP-Link cementless distal fixation modular prosthesis for unstable intertrochanteric fractures in patients aged 75 years or more, do not need to reconstruct the femoral calcar. MATERIALS AND METHODS: Forty-two patients (42 hips) underwent bipolar HA using the MP-Link cementless distal fixation modular prosthesis for unstable intertrochanteric fractures from January 2008 to January 2012. Five (11.9%) patients were lost to follow-up. The 37 remaining patients (37 hips) were available for evaluation. The mean age was 83.9±5.2 years. Their clinico-radiological data were prospectively gathered. RESULTS: All of 37 patients, 4 patients (10.8%) died within 1 year postoperatively. At the final follow-up, 31 (83.8%) out of 37 patients were regained preoperative ambulatory status; the mean Harris hip score (HHS) of the 15 patients who died during the follow-up period of 7-59 months, was 84.5±2.4 points; the 22 healthy patients were followed for 68.6±14.7 months, with mean HHS of 84.6±2.8 points. Radiologically, none of stems had evidence of loosening; 16 stems had subsidence of 2-3mm without clinical significance; the bone in-growth fixation was achieved in 24 patients and stable fibrous fixation in 13 patients. DISCUSSION: Bipolar HA using the MP-Link cementless distal fixation modular prosthesis for unstable intertrochanteric fractures in patients aged 75 years or more, without reconstruction of the femoral calcar, may achieve a satisfactory clinico-radiological outcome, and could regain preoperative ambulatory status in most patients (83.3%). LEVEL OF EVIDENCE: IV, Retrospective study.

Delayed total hip arthroplasty after failed treatment of acetabular fractures: an 8- to 17-year follow-up study.

BACKGROUND: Delayed total hip arthroplasty (THA) is a reliable procedure following failed treatment of acetabular fractures. The aim of the present study was to evaluate the influence of the type of fracture treatment and modern ceramic bearing on the clinical outcomes of delayed THA. METHODS: Between January 1997 and January 2008, 33 patients (33 hips) underwent cementless THA after failed acetabular fractures. Twenty-one were initially treated by open reduction internal fixation (ORIF) and 12 had non-ORIF. Joint articulation was either conventional metal-on-polyethylene (MOP) or ceramic-on-ceramic (COC). Intraoperative measures and preoperative and follow-up clinical, radiological, and functional outcomes were compared between the ORIF and non-ORIF groups. RESULTS: Surgery duration, blood loss, and transfusion requirement were greater in the ORIF group than in the non-ORIF group (p < 0.05). Significant improvement in Harris Hip Scores was seen post-surgery in both groups. However, a significant difference in the mean Harris Hip Score was not observed between the two groups (p = 0.57). Six patients in the ORIF group required acetabular reconstructive procedures to address bony defects compared to seven patients in the non-ORIF group (p = 0.09). The rate of anatomical restoration was 58.3% (7/12) in the non-ORIF group and 42.9% (9/21) in the ORIF group (p = 0.12). Radiolucent lines were observed in the MOP group and none in the COC group. Overall survival rate was similar in both groups (p = 0.85): 89.3% in the ORIF group and 87.5% in the non-ORIF group. CONCLUSION: Delayed THA with previous acetabular fractures is a challenging procedure. Initial fracture treatment does not influence the outcome of delayed THA, and modern ceramic bearing has promising results in the long-term follow-up.

[Comparative study on association between femoral head size and linear wear rate of highly cross-linked polyethylene liner].

OBJECTIVE: To investigate the effects of the femoral head size on the linear wear rate of highly cross-linked polyethylene (HXLPE) liner in total hip arthroplasty (THA). METHODS: A retrospective analysis was performed on the clinical data of 41 patients (43 hips) who underwent primary THA with HXLPE liner and different sizes of femoral heads between January 2004 and December 2007 for hip diseases. There were 22 males (23 hips) and 19 females (20 hips) with a mean age of 60.2 years (range, 35-89 years), including femoral neck fracture (26 hips), avascular necrosis of femoral head (8 hips), osteoarthritis (5 hips), rheumatoid arthritis (2 hips), and congenital hip dysplasia (2 hips). According to the size of the femoral head, the patients were divided into 2 groups: standard head size (26 and 28 mm) was used in 25 cases (26 hips, group A) and big head size (32, 36, and 40 mm) in 16 cases (17 hips, group B). The cumulative penetration of the femoral head, linear wear rate, and effectiveness were evaluated and compared between 2 groups. RESULTS: All the incisions healed by first intention, no complications of infection, deep vein thrombosis, or nerve injury occurred. The patients were followed up 5-9 years (mean, 5.7 years). No two-stage revision was needed. Harris score was significantly improved at 3 months, 6 months, and 1, 2, 3, 4, and 5 years after operation when compared with preoperative score in each group (P < 0.05), but no significant difference was found between different time points after operation in 2 groups (P > 0.05), and between 2 groups at each time point (P > 0.05). Acetabular abduction angle was (31.4 ± 3.8)° in group A and (32.3 ± 4.1)° in group B, showing no significant difference (t = 0.482, P = 0.621). At last follow-up, no radiographic or clinical loosening was observed in each group. At 5 years after operation, X-ray results of acetabular components showed radiolucent line (< 1 mm) in 1 case (1 hip) and 1 case (1 hip) of 2 groups respectively; but X-ray results of femoral components showed no radiolucent line. There was no significant difference in the cumulative penetration of the femoral head between 2 groups at 1, 2, 3, 4, and 5 years after operation (P > 0.05). The linear wear rate was (0.026 ± 0.007) mm/year in group A and (0.025 ± 0.007) mm/year in group B, showing no significant difference between 2 groups (t = -0.708, P = 0.483). CONCLUSION: No association is found between femoral head size and the linear wear rate of HXLPE liner. It is an ideal interface of THA because of its low linear wear rate.

Electrospun nanofibrous scaffolds of poly (L-lactic acid)-dicalcium silicate composite via ultrasonic-aging technique for bone regeneration.

Polymeric nanofibrous composite scaffolds incorporating bioglass and bioceramics have been increasingly promising for bone tissue engineering. In the present study, electrospun poly (l-lactic acid) (PLLA) scaffolds containing dicalcium silicate (C2S) nanoparticles (approximately 300 nm) were fabricated. Using a novel ultrasonic dispersion and aging method, uniform C2S nanoparticles were prepared and they were homogenously distributed in the PLLA nanofibers upon electrospinning. In vitro, the PLLA-C2S fibers induced the formation of HAp on the surface when immersed in simulated body fluid (SBF). During culture, the osteoblastic MC3T3-E1 cells adhered well on PLLA-C2S scaffolds, as evidenced by the well-defined actin stress fibers and well-spreading morphology. Further, compared to pure PLLA scaffolds without C2S, PLLA-C2S scaffolds markedly promoted the proliferation of MC3T3-E1 cells as well as their osteogenic differentiation, which was characterized by the enhanced alkaline phosphatase (ALP) activity. Together, findings from this study clearly demonstrated that PLLA-C2S composite scaffold may function as an ideal candidate for bone tissue engineering.

Improvement of PHBV scaffolds with bioglass for cartilage tissue engineering.

Polymer scaffold systems consisting of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) have proven to be possible matrices for the three-dimensional growth of chondrocyte cultures. However, the engineered cartilage grown on these PHBV scaffolds is currently unsatisfactory for clinical applications due to PHBV's poor hydrophilicity, resulting in inadequate thickness and poor biomechanical properties of the engineered cartilage. It has been reported that the incorporation of Bioglass (BG) into PHBV can improve the hydrophilicity of the composites. In this study, we compared the effects of PHBV scaffolds and PHBV/BG composite scaffolds on the properties of engineered cartilage in vivo. Rabbit articular chondrocytes were seeded into PHBV scaffolds and PHBV/BG scaffolds. Short-term in vitro culture followed by long-term in vivo transplantation was performed to evaluate the difference in cartilage regeneration between the cartilage layers grown on PHBV and PHBV/BG scaffolds. The results show that the incorporation of BG into PHBV efficiently improved both the hydrophilicity of the composites and the percentage of adhered cells and promoted cell migration into the inner part the constructs. With prolonged incubation time in vivo, the chondrocyte-scaffold constructs in the PHBV/BG group formed thicker cartilage-like tissue with better biomechanical properties and a higher cartilage matrix content than the constructs in the PHBV/BG group. These results indicate that PHBV/BG scaffolds can be used to prepare better engineered cartilage than pure PHBV.

[Comparative study on high cross-linked and traditional polyethylene cup liners in total hip arthroplasty].

OBJECTIVE: To compare the effectiveness and linear wear rates between high cross-linked polyethylene cup liner and traditional polyethylene cup liner. METHODS: A retrospective analysis was made on the clinical data of 61 patients (64 hips) who underwent primary total hip arthroplasty (THA) between January 2005 and March 2007. According to the type of cup liner, 61 patients (64 hips) were divided into 2 groups: high cross-linked polyethylene cup liner was used in 30 cases (31 hips, trial group), and traditional polyethylene cup liner in 31 cases (33 hips, control group). There was no significant difference in gender, age, body weight, etiological factor, and preoperative Harris score between 2 groups (P > 0.05). Complication was observed after operation; Harris score was used to assess hip function; X-ray film analysis was done to observe osteolysis and prosthesis loosening, and to measure cumulative penetration of the femoral head and linear wear rate. RESULTS: All incisions healed by first intention without complication. All patients were followed up. The mean follow-up was 6.3 years (range, 5-7 years) in trial group, and was 6.5 years (range, 4-7 years) in control group. There was no significant difference in Harris score between 2 groups at the 3 months after operation and last follow-up (P > 0.05). Osteolysis was observed in 3 cases (3 hips) of control group, but no osteolysis in trial group. X-ray films showed no aseptic loosening in the patients of 2 groups. The mean cumulative penetration of trial group were significantly lower than those of control group at 1-7 years after operation (P < 0.05). Linear wear rate of trial group [(0.025 +/- 0.002) mm/year] was significantly lower than that of control group [(0.086 +/- 0.005 ) mm/year] (Z=6.804, P=0.000). CONCLUSION: High cross-linked polyethylene cup liner has the similar effectiveness as traditional polyethylene cup liner, but it has lower linear wear rate than the traditional polyethylene cup liner.

Adhesion, proliferation and differentiation of osteoblasts on zirconia films prepared by cathodic arc deposition.

Zirconia films were prepared on titanium by cathodic arc deposition technique. The surface topography and element composition of the films were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively. Osteoblast-like MG63 cells were cultured on the surface of the zirconia films in vitro, and cell behaviour was investigated, with titanium as control. The results obtained from scanning electron microscopy and immunofluorescence studies showed that the MG63 cells on ZrO2 films spread better than those on Ti. The CCK8 assay indicated that the zirconia films promoted the proliferation of MG63 cells. The results of alkaline phosphatase (ALP) activity test and the expression of osteogenic marker genes, such as ALP, collagen I and osteocalcin, demonstrated that the differentiation of MG63 cells might be enhanced by zirconia films. In addition, the zirconia films possibly regulated osteoclastogenic gene expression by stimulating the expression of osteoprotegerin and reducing the expression of receptor activator of nuclear factor-kappaB ligand. The present work suggests that the ZrO2 film is worth further consideration for orthopedic implant applications.

Proliferation and differentiation of osteoblastic cells on silicon-doped TiO(2) film deposited by cathodic arc.

This study aimed at the proliferation and differentiation of osteoblastic cells on silicon-doped TiO(2) and pure TiO(2) films prepared by cathodic arc deposition. The films were examined by X-ray photo-electron spectroscopy, which showed that silicon was successfully doped into the Si-TiO(2) film. Meanwhile, no significant difference was found between the surface morphology of silicon-doped TiO(2) and pure TiO(2) films. When osteoblastic cells were cultured on silicon-doped TiO(2) film, accelerated cell proliferation was observed. Furthermore, cell differentiation was evaluated using alkaline phosphatase (ALP), type I collagen (COL I) and osteocalcin (OC) as differentiation markers. It was found that ALP activity, the expression levels of OC gene, COL I gene and protein were up-regulated on silicon-doped TiO(2) film at 3 and 5 days of culture. Moreover, no significant difference was found in apoptosis between the cells cultured on silicon-doped TiO(2) and pure TiO(2) films. Therefore, findings from this study indicate that silicon-doped film favors osteoblastic proliferation and differentiation, and has the potential for surface modification of implants in the future.

Osteoblast-like cell adhesion on porous silicon-incorporated TiO2 coating prepared by micro-arc oxidation.

Silicon-incorporated TiO(2) coating (Si-TiO(2) ) was prepared on titanium (Ti) by micro-arc oxidation (MAO) technique in the Ca, P, Si-containing electrolyte. The surface topography, phase, and element composition of the coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectrometry (EDS), respectively. Osteoblast-like MC3T3-E1 cells were cultured on the surface of the coatings to evaluate their adhesion behavior. The obtained results showed that Si element was successfully incorporated into the porous TiO(2) coating, which did not alter apparently the surface topography and phase composition of the coating. The adhesion of the MC3T3-E1 cells on Si-incorporated TiO(2) coating was significantly enhanced compared with the Si-free TiO(2) coating and pure Ti plates. In addition, the enhanced cell adhesion may at least partly be mediated by integrin ß1-FAK signal transduction pathway. The present work suggests that the Si-TiO(2) coating is worth further consideration for orthopedic implant applications.

Treatment of high-energy tibial shaft fractures with internal fixation and early prophylactic NovaBone grafting.

OBJECTIVE: To evaluate the safety and efficacy of early NovaBone grafting in accelerating healing of high-energy tibial shaft fractures. METHODS: In a prospective, randomized, controlled study 78 patients with open or closed tibial shaft fractures were treated with reamed interlocking nails, combined with NovaBone grafting. Forty patients were randomly assigned to the experimental group (with NovaBone grafting at fracture site), and 38 to the control group (without NovaBone grafting). RESULTS: All patients were followed up for an average of 8 months (range 6-18 months). The average fracture healing time was 12 weeks (range 8-16 weeks) in the experimental group, and 19 weeks (range 12-36 weeks) in the control group (P < 0.01). No delayed union or nonunion was found in the experimental group, but four cases (10.5%) in the control group were found to heal spontaneously between 7 and 8 months. When the data were analyzed at week 12 and week 26 according to the criteria of Johner and Wruhs, 88% and 100% of the cases in the experimental group were rated as excellent and good respectively, but in the control group, 50% and 89% were rated as excellent and good respectively, these being significant differences (P < 0.05). CONCLUSION: Internal fixation supplemented with early prophylactic NovaBone grafting of high-energy tibial shaft fractures is a safe and effective treatment which accelerates fracture healing.

[Repairing bone defects of benign bone neoplasm by grafting of bioactive glass combined with autologous bone marrow].

OBJECTIVE: To investigate the clinical application of grafting with bioactive glass (BG) and autologous bone marrow for defect after resection and curettage of benign bone neoplasm. METHODS: From January 2004 to May 2007, 34 patients with bone defects were repaired. There were 21 males and 13 females with a mean age of 25.6 years (8 to 56 years). There were 14 cases of simple bone cysts, 6 cases of fibrous dysplasia, 3 cases of osteoid osteoma, 4 cases of non-ossifying fibroma, 2 cases of enchondroma and 3 cases of giant cell tumor of bone. Tumor sizes varied from 2.0 cm x 1.5 cm x 1.0 cm to 9.0 cm x 3.0 cm x 2.5 cm. Benign bone neoplasm was removed thoroughly with a curet or osteotome, bone defects ranged from 3.0 cm x 2.0 cm x 1.5 cm to 11.0 cm x 3.5 cm x 3.0 cm, which was closed-up with the mixtures of BG and autogenous red bone marrow. Six cases of pathologic fracture were fixed with steel plate or intramedullary nail. The postoperative systemic and local reactions were observed, and the regular X-ray examinations were performed to observe the bone healing. RESULTS: All the patients had good wound healing after operation. There was no yellow effusion nor white crystal and skin rash appeared around wound, indicating no allergic reaction occurred. A follow-up of 1 to 4 years (mean 24.6 months) showed satisfactory healing without complications. At averaged 16 weeks after operation, patients with bone tumor in lower limbs resumed walking independently and those with bone tumor in upper limbs resumed holding object. There was no tumor recurrence during follow-up. Radiographically, the interface between the implanted bone and host bone became fuzzy 1 month after implantation. Two months after operation, the BG was absorbed gradually, new bone formation could be seen in the defects. Four months after operation, implanted bone and host bone merged together, bone density increased. Six to ten months after operation, the majority of the implanted BG was absorbed and substituted for new bone, bone remodeling was established. CONCLUSION: BG may boast both bone conductive and bone inductive activities. The combined grafting with BG and autologous bone marrow appears to be minimally invasive treatment to repair bone defects of benign bone neoplasm, with rare complications and no significant reverse reaction, and could repair bone defects completely.