Junjie Shao

Human β-defensin 3 inhibits antibiotic-resistant Staphylococcus biofilm formation

BACKGROUND Implantation-associated infections have increased significantly with the recent widespread use of medical implants. Treatments for these infections are not always successful because these infections are sometimes caused by multiantibiotic-resistant organisms. It is therefore particularly urgent to provide doctors with more effective antimicrobial agents against these antibiotic-resistant organisms. Human β-defensin 3 (hBD-3) has been shown to have strong broad-spectrum antibacterial activity. However, its effect on methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus aureus (MRSA) in medical implant biofilm formation has not been reported. METHODS In this study, we evaluated the effects of hBD-3 on S epidermidis ATCC 35984 (methicillin-resistant strain), MRSE287, and MRSA (ATCC43300) by evaluating bacterial adhesion, biofilm formation, and maturation. In addition, we used the spread plate method, confocal laser scanning microscopy, scanning electron microscopy, and real-time polymerase chain reaction to evaluate the effect of hBD-3. RESULTS After evaluating biofilm adhesion and formation, we found that the number of each strain on the titanium surface was decreased in those groups exposed to 1MIC (minimum inhibitory concentration) of hBD-3 and was significantly lower than the number of colonies of the control. In the initial maturation of the biofilm, the numbers of each strain on the titanium surface from the 2MIC to 6MIC groups were significantly lower than the control. When the concentrations were further increased, hBD-3 was significantly effective against drug-resistant bacteria from the biofilms. CONCLUSIONS HBD-3 has the potential to eliminate the biofilm formation of Staphylococcus, especially antibiotic-resistant strains, effectively.

Intraoperatively-made cement-on-cement antibiotic-loaded articulating spacer for infected total knee arthroplasty

Cement articulating spacers have been used for the treatment of TKA infection. The disadvantages of commercially available pre-made mobile spacers include limitations in implant size and antibiotic dose, often allowing delivery of only a single antibiotic agent. Hand-made mobile spacers fail to provide a well-shaped and congruently articular surface and have difficulties in maintaining stability. We present a method of intraoperatively-made cement-on-cement antibiotic-loaded articulating spacer for infected total knee arthroplasty. A custom mold was made intraoperatively with bone cement and the standard posterior stabilized TKA provisional components which were of the same size as the original prosthesis. Fabrication of the spacers did not increase the overall surgical time. From 2004 to 2007, 17 infected total knee arthroplasties were treated with two-stage reimplantation. The average length of follow-up was 31 months. One patient required an above-knee amputation for persistent infection. A knee arthrodesis was performed in one case. Ten patients received reimplantation with Nexgen LCCK knee implants. Articulating spacers were retained in situ in five patients. This articulating spacer can help improve knee mobility and function during the interval between stages.

Resurfacing arthroplasty for hip dysplasia: A prospective randomised study

In this prospective study a total of 80 consecutive Chinese patients with Crowe type I or II developmental dysplasia of the hip were randomly assigned for hip resurfacing arthroplasty (HRA) or total hip replacement (THR). Three patients assigned to HRA were converted to THR, and three HRA patients and two THR patients were lost to follow-up. This left a total of 34 patients (37 hips) who underwent HRA and 38 (39 hips) who underwent THR. The mean follow-up was 59.4 months (52 to 70) in the HRA group and 60.6 months (50 to 72) in the THR group. There was no failure of the prosthesis in either group. Flexion of the hip was significantly better after HRA, but there was no difference in the mean post-operative Harris hip scores between the groups. The mean size of the acetabular component in the HRA group was significantly larger than in the THR group (49.5 mm vs 46.1 mm, p = 0.001). There was no difference in the mean abduction angle of the acetabular component between the two groups. Although the patients in this series had risk factors for failure after HRA, such as low body weight, small femoral heads and dysplasia, the clinical results of resurfacing in those with Crowe type I or II hip dysplasia were satisfactory. Patients in the HRA group had a better range of movement, although neck-cup impingement was observed. However, more acetabular bone was sacrificed in HRA patients, and it is unclear whether this will have an adverse effect in the long term.

Superior mineralization and neovascularization capacity of adult human metaphyseal periosteum-derived cells for skeletal tissue engineering applications.

Bone tissue engineering is a promising cell-based strategy to treat bone defects. Mesenchymal stem cells from adult human bone marrow (hBMSCs) are a frequently used cellular source for bone tissue generation. However, the low frequency of these stem cells in adult bone marrow and their limited proliferation restrict their clinical utility. An alternative source of MSCs is the periosteum-derived cells, and these cells appear to be easy to harvest and expand ex vivo. We isolated human metaphyseal periosteum-derived cells (hMPCs) and hBMSCs from the same donors and compared their osteogenic capacity both in vitro and in vivo. After osteogenic induction in monolayer cultures, hMPCs resulted in more robust mineralization and expressed higher mRNA levels of BMP-2, osteopontin and osteocalcin than hBMSCs. Eight weeks after implantation of cellular-β-TCP scaffolds in immunodeficient mice, hMPC implantation showed higher neovascularization and higher percentage of mature bone formation than hBMSC implantation. In conclusion, hMPCs represent a promising cellular candidate for bone tissue engineering.

Staged reimplantation for the treatment of fungal peri-prosthetic joint infection following primary total knee arthroplasty.

BACKGROUND Fungal peri-prosthetic joint infections (PJI) are rare complication following total knee arthroplasty (TKA). There exists no established guidelines in the treatment of these infections and controversies are focused on the usefulness of antifungal-loaded cement spacers, the duration of systemic antifungal treatment and the ideal interval between implant removal and reimplantation. Therefore we ask if: (1) adding antifungal in cement space is a viable solution to manage fungal PJI; (2) there is no adverse effect adding antifungal medication in cement? HYPOTHESIS We hypothesized that fungal PJI following TKA could be managed successfully by 2-stage reimplantation strategy using antifungal-loaded cement spacer. PATIENTS AND METHODS Five cases of fungal PJI following total knee arthroplasty were treated in our institution between 2007 and 2013 using a 2-stage reimplantation strategy. The median elapsed time from primary arthroplasty to the diagnosis of infection was 7.4 months (range, 5-10 months). The infection was caused by Candida species in 4 cases and Pichia anomala in 1 case. Antibiotic- and antifungal-loaded articulating cement spacer was implanted during the interval between stages. Systemic antifungal agents were administered for at least 6 weeks after removal of prosthesis in all cases. The mean interval between removal and reimplantation was 6 months (range, 3-9 months). RESULTS At a mean follow-up of 41.6 months (range, 24-65 months) after reimplantation, no patient had recurrent infection or revision due to any other reasons. The mean global IKS score improved from 58.4 (range, 37-96 points) preoperatively to 152.4 (range, 136-169 points) at final follow-up. The average range of motion of the knee for flexion improved from 63° (range, 10-110°) preoperatively to 98° (range, 80-120°) at final follow-up. CONCLUSIONS Fungal PJI following TKA can be successfully treated by a staged reimplantation strategy. Antibiotic- and antifungal-loaded cement spacer implanted during interval period between stages may be an effective adjunct to therapy. Effective antifungal therapy is crucial to a successful result without adverse effect. LEVEL OF EVIDENCE IV: retrospective or historical series.

Cementless total hip arthroplasty for the treatment of advanced tuberculosis of the hip.

The question of whether a total hip arthroplasty (THA) should be attempted in a patient with a current or previous tuberculosis infection continues to cause controversy. The goal of this study was to evaluate the clinical result of cementless THA for the treatment of advanced tuberculosis of the hip. Eight patients with advanced tuberculosis of the hip treated by cementless THA were retrospectively analyzed. None of the patients had draining sinus preoperatively. For patients with a confirmed preoperative diagnosis of tuberculosis and elevated C-reactive protein and erythrocyte sedimentation rate, antituberculous medication was prescribed for at least 2 weeks preoperatively. Inflamed soft tissues and destroyed bones were completely curetted out intraoperatively. All 8 patients received 1-stage cementless THA after thorough debridement. Antituberculous medications were prescribed for all patients for the first 6 months postoperatively. No patient experienced wound-healing complications. Mean Harris Hip Score was 35 (range, 30-43) preoperatively and 91 (range, 87-95) at last follow-up. At an average 46-month follow-up (range, 34-59 months), no reactivation of tuberculosis was detected. All 8 patients revealed stability by bone ingrowth on both the socket and femoral stem. Cementless THA is a safe and effective procedure for advanced tuberculosis of the hip. With thorough debridement followed by a complete course of antituberculous chemotherapy, active tuberculous infection should not be considered a contraindication for THA.

Computer-navigated TKA for the treatment of osteoarthritis associated with extra-articular femoral deformity.

The purpose of this study was to evaluate the efficacy of computed-navigated total knee arthroplasty for the treatment of osteoarthritis associated with extra-articular femoral deformity. Between January 2008 and June 2010, twelve patients (12 knees) with osteoarthritis combing extra-articular femoral deformity underwent total knee arthroplasty using the Stryker Navigation System 3.1 (Kalamazoo, Michigan), a wireless and imageless system. Average follow-up was 12.3 ± 8.2 months (range, 3-24 months). Full-length weight-bearing anteroposterior radiographs, knee range of motion, and Knee Society Score were obtained for all patients pre- and postoperatively. The data were analyzed with SPSS version 12.0 statistical software (SPSS, Inc, Chicago, Illinois). Average preoperative overall mechanical axis of the 12 knees was -10.0° ± 4.4° of varus (range, -5° to -18.5°) and average postoperative mechanical axis was -0.9° ± 0.8° (range -2° to 0°). Average Knee Society Score increased from 40.8 ± 7.7 preoperatively to 94.9 ± 2.4 postoperatively, and average function score increased from 39.6 ± 12.3 preoperatively to 95.4 ± 4.0 postoperatively. Average knee range of motion improved from 83.7° ± 18.7° preoperatively to 115.0° ± 8.2° postoperatively. The results of the study showed that computer-navigated total knee arthroplasty may be a valuable option for patients with deformed femurs in which conventional instruments are difficult to use. Follow-up observation of the long-term therapeutic effect of computer-navigated total knee arthroplasty is still needed.