Preparation, release profiles and antibacterial properties of vancomycin-loaded Ca-P coating titanium alloy plate.

The aim of the study was to explore the feasibility of the Ca-P coating titanium alloy plate to be used as the vancomycin drug-delivery system by biomimetic coating technology. Through the X-ray diffraction study, the main components of the coatings were identified as octocalcium phosphate. The in vitro vancomycin release, bacteriostasis activity to Staphylococcus aureus (S. aureus), the scanning electron microscope (SEM) image and osteoblast adhesion and proliferation test of vancomycin-loaded Ca-P coating plate were evaluated. The bacteriostatic activity of the vancomycin-loaded Ca-P coating plate showed a continuous drug release and had an inhibitory effect on the growth of the S. aureus. In vitro osteoblast culture results showed that the Ca-P coating plate loaded with or without the vancomycin both obviously promoted the osteoblast attachment. It was suggested that the vancomycin-loaded Ca-P coating may be compounded in the surface of the internal fixators to reduce the incidence of the implant-associated infection.

[Antibiotic-loaded cement articulating spacer made by a self-made mold system in the treatment of the infected hip replacement].

OBJECTIVES: To summarize the experience and lessons of the using of antibiotic-loaded cement articulating spacer made by a self-made mold system for the treatment of the infected hip replacement, and to evaluate its efficiency and role in the two-stage revision of infected total hip arthroplasty (THA). METHODS: The patients with infected THA treated with two-stage revision protocol from August 2005 to December 2009 were reviewed. All of the 127 patients were debridement thoroughly and followed by implantation of an antibiotic-loaded cement articulated spacer made by a self-made mold system; Two-stage revisions were not followed until the infection were controlled. Among of them, 106 patients, 107 hips were gotten fully followed up. Evaluations were made for the efficiency of infection control, convenience of making, implanting and removing of the spacers, occurrence of complications, the deal of the special circumstances, the function and satisfaction of the patients. RESULTS: The 107 hips were gotten an average of 34.3 months' (3 - 55 months) follow-up. The infection control rate was 96.3% after the first-stage surgery, the infection control rate was 94.4% at last follow-up after two-stage revisions. The breakage rate of the spacer was 4.7%, dislocation rate was 2.8%, removal of the spacers with difficulty were seen in 15 patients (14.0%). The satisfactory rate of the patients was 93.5%. CONCLUSIONS: Antibiotic-loaded cement articulating spacer made by a self-made mold system is an effective methods for the two-stage revision of the infected hip replacement, characterized by simple, good reproducible, high rates of infection control, better joint function after surgeries, high rate of patients satisfaction and other advantages. And it can decrease the complications, such as the breakage, spacer dislocation of hip joint and difficulty in removal of spacer at the second stage revision. Using of metallic internal fixation or allograft bone combined with spacer does not affect the results of infection controlling.

Finite Element Assessment of the Screw and Cement Technique in Total Knee Arthroplasty.

BACKGROUND: The screw and cement technique is a convenient method used to rebuild medial tibial plateau defects in primary total knee arthroplasty (TKA). The objective of this study was to perform a finite element assessment to determine the effect of different numbers of screws on the stability of TKA and to determine whether differences exist between two different insertion angles. METHOD: Six tibial finite element models with defects filled with screws and cement and one model with defects filled only with cement were generated. Contact stresses on the surface of cancellous bone in different areas were calculated. RESULTS: Compared to the cement-only technique, the stress on the border of cancellous bone and bone cement decreased by 10% using the screw and cement technique. For bone defects with a 12% defect area and a 12-mm defect depth, the use of 1 screw achieved the greatest stability; for those with a 15% defect area and a 20-mm defect depth, 2 screws achieved the greatest stability. CONCLUSIONS: (1) The screw and cement technique is superior to the bone cement-only technique. For tibial defects in which the defect area comprises a large percentage but the depth is less than 5 mm, the screw and cement technique is recommended. (2) Vertical screws can achieve better stability than oblique screws. (3) Screws should be used in moderation for different defects; more is not always better.

Combined antibacterial and osteogenic in situ effects of a bifunctional titanium alloy with nanoscale hydroxyapatite coating.

To resolve the problems of bacterial infections and the low efficiency of osteogenesis of implanted titanium alloys in clinical dental and bone therapy, we developed a bifunctional titanium alloy (Ti) with a nano-hydroxyapatite (HA) coating (HBD + BMP/HA-Ti), which enables the sustained release of the natural antimicrobial peptide human ß-defensin 3 (HBD-3) and bone morphogenetic protein-2 (BMP-2). Due to the poriferous nano-sized structure of the HA coating with a 20-30 µm thickness, the HBD + BMP/HA-Ti material had a high encapsulation efficiency (>74%) and exhibited synchronized slow release of HBD-3 and BMP-2. In an antibacterial test, HBD + BMP/HA-Ti prevented the growth of bacteria in an inoculated medium, and its surface remained free from viable bacteria after a continuous incubation with Gram-negative and Gram-positive strains for 7 days. Furthermore, good adhesion, proliferation and osteogenic differentiation of hBMSCs in contact with HBD + BMP/HA-Ti were achieved in 7 days. Therefore, the bifunctional titanium alloy HBD + BMP/HA-Ti has a great potential for eventual applications in the protection of implants against bacteria in the orthopaedic and dental clinic.

[Mechanical complications with self-made, antibiotic-loaded cement articulating spacers in the treatment of the infected hip replacement].

OBJECTIVE: To study the complications and efficacy of self-made, antibiotic-loaded cement articulating spacers in the treatment of the infected hip replacement. METHODS: Between January 2006 and July 2016, 265 patients (266 hips) received a self-made, antibiotic-loaded cement articulating spacer as part of a two-stage protocol. Among those patients, there were 143 males(144 hips) and 122 females(122 hips). The cement articulating spacers with vancomycin and two Steinman pins were made by a self-made mold system. Meanwhile, another antibiotic was added to the spacers according to the drug sensitivity test. Record if the infected prosthesis was removed, related complication with spacer(breakage and dislocation), Harris score, and control rate of infection. RESULTS: The mean age of two-stage revision operation was(57.4±14.2) years. Thirty-nine patients(14.7%) used extended trochanteric osteotomy(ETO) to remove the infected prosthesis. And 38 patients occurred mentioned complications(14.3%). Spacer breakage occurred in 28 cases(10.5%) and dislocation occurred in 10 cases(3.8%). The mean follow-up time was(83.4±14.6) months. The Harris hip score was from 47.56±14.23 preoperatively to 86.43±12.84 at final follow-up(P<0.05). The infection of 256 cases(96.6%) got control after revision operation. However, during postoperative follow-up, 4 cases occurred re-infection, and they were reoperated, and the infections obtained effective control after the operation. Thus total infection control rate was 95.1%(252/265). CONCLUSIONS: Antibiotic-loaded cement articulating spacer made by a self-made mold system is effective in controling infection caused by hip replacement. Related complication is less with spacer by a mould enclosing two Steinman pins. Using metallic internal fixation or allograft bone combined with spacer does not affect infection control.

[Management of the bone defects in revision total hip arthroplasty].

OBJECTIVE: To determine the efficiency and clinical outcome of impaction bone graft in revision total hip arthroplasty (THA). METHODS: Seventy-two revision THAs by using impaction bone graft in 48 patients with severe bone loss were gotten average 25 months follow-up. Harris hip scores and X-ray were used to evaluate the results. RESULTS: The mean Harris hip scores improved from 44.6 before operation to 87.4 after operation. The excellent and good results were 90.3%. No stem subsidence and cup migration were found. Femoral fracture rate was 4.2%, and dislocation rate was 1.4%. CONCLUSION: Impaction bone graft is an efficacious method to restore bone stock in revision THA, and using anatomic stem and freeze-drying cancellous bone allograft could also get good clinical result.

[Treatment of infected total knee arthroplasty with a self-made, antibiotic-loaded cement articulating spacer].

OBJECTIVE: To study the efficacy of self-made, antibiotic-loaded cement articulating spacer in the treatment of infected total knee arthroplasty. METHODS: The self-made molds were used to form the spacer during the operation. From March 2002 to March 2007, 22 patients with infected knee arthroplasty (10 males with 10 knees, 12 females with 12 knees) were treated with this kind of spacer in our center. The mean age of the patients was 59.6 years old (33 to 75 years old). The interval time between primary arthroplasty and first onset of infective syndrome was 6.7 months (1 to 14 months). The diagnosis was established by the clinical presentation,serum laboratory inflammatory markers (white blood cell count,erythrocyte sedimentation rate and C-reactive protein) and knee aspiration. The serum laboratory inflammatory markers were used to measure the systemic response to infection. Clinical and radiographic follow-up was regularly performed by HSS score system and X-ray. RESULTS: All the patients were followed, the average interval between debridement and reimplantation was 4.7 months (3 to 9 months) and the infection control rate was 100% after the implantation of spacer. The average follow-up duration after reimplantation was 29.8 months (10 to 64 months) and there was no recurrence of infection at the latest follow-up. The HSS score increased from 40.5+/-5.9 to 65.8+/-7.5 after the implantation of spacer, furthermore, the score reached 88.7+/-5.1 in average at the latest follow-up. The patient satisfaction rate was 95.3%. CONCLUSION: This self-made molds and spacers is a reliable approach for the management of infected knee arthroplasty with some virtues, such as providing a mobile and functional joint through the treatment course, decreasing the difficulty of reimplantation, avoiding of a long-term post-operative infusion and high effective for eradicating infection.

Antibiotic-impregnated cement spacer versus antibiotic irrigating metal spacer for infection management after THA.

We prospectively compared the effects of an antibiotic-impregnated cement spacer and an antibiotic irrigating metal spacer in the treatment of infections after total hip arthroplasty (THA) to determine a better method for 2-stage revision of infected THA. We used a uniform protocol of a 3-month spacer interval and specific local and systemic antibiotic therapies. The clinical outcome was determined by assessing operation time, blood loss during spacer implantation, hospital stay and time in bed, and joint function. The patients were followed for a mean 61.4 months (range, 24-94 months). Antibiotic-impregnated cement spacers had a higher rate of infection control than antibiotic irrigating metal spacers (96.2% vs 76%, respectively; P<.01), with no recurrence of infections or implant loosening. Patients receiving antibiotic-impregnated cement spacers had a shorter operation time (2.42±0.65 vs 3.34±0.36 hours metal spacers; P<.01), less blood loss (1085.48±279.49 vs 1964.78±469.23 mL metal spacers; P<.01), a shorter hospital stay (24.53±4.72 days vs 51.36±3.46 days metal spacers; P<.01), and better function before the second step of the 2-stage revision (Harris Hip Score, 88.16±6.94 vs 79.54±6.48 metal spacers; P<.05), and they were free from long-term irrigation. Compared with the antibiotic irrigating metal spacer, the antibiotic-impregnated cement spacer is characterized by higher infection control rate, better joint function recovery before the second operation, shorter operation time, and less blood loss, with no continuous irrigation required.

Efficacy of a norvancomycin-loaded, PDLLA-coated plate in preventing early infection of rabbit tibia fracture.

Despite improvements in surgical techniques and implant designs in orthopedic surgery, implantation-associated infections are still a challenging problem for surgeons. The goal of this study was to evaluate the efficacy of a norvancomycin-loaded, PDLLA-coated stainless steel plate vs an uncoated stainless steel plate in a rabbit model (n=50). The norvancomycin was delivered from a biodegradable poly(D,L-lactide) (PDLLA) coating of a stainless steel plate. Intraoperatively, rabbit tibia fractures were contaminated with Staphylococcus aureus (10(5) colony forming units) after plate implantation. The implants were either uncoated or coated with PDLLA and norvancomycin. In vivo drug release profiles showed that the norvancomycin release rate was decreased by increasing the time. The norvancomycin concentration in the tissue around the plate was higher than the minimum inhibitory concentration on the 14th day after implantation surgery. The animals were followed up for 28 days. Radiographic examinations were performed, and C-reactive protein and erythrocyte sedimentation rate were determined. Infection was evaluated by histological, microbiological, and radiological analysis. Eight of 25 rabbits (32%) implanted with the norvancomycin-loaded, PDLLA-coated plates were infected. Twenty-three of 25 rabbits (92%) implanted with the uncoated plates were infected (P<.05). The norvancomycin-loaded, PDLLA-coated plate may be used to treat open fractures to reduce the incidence of early infection.