Despite improvements in surgical techniques and implant design in orthopedic surgery, implantation-associated infections are still a challenging problem for surgeons. In 2006, trace quantities of human β-defensin 3 (hBD-3) were found in human bone tissue and bone cells. Human β-defensin 3 is a 45-amino-acid peptide that is considered the most promising class of defensin antimicrobial peptides and may help in the prevention and treatment of implantation-associated infections. Studies of the effectiveness of hBD-3 against Staphylococcus aureus showed that hBD-3 was more potent at low concentrations than other antibiotics. The effect of hBD-3 on S aureus biofilms has not been reported. We studied the effect of hBD-3, vancomycin, and clindamycin on S aureus biofilms and on the survival of the bacteria in the biofilms.Staphylococcus aureus biofilms were examined with confocal scanning laser microscopy. Staining with LIVE/DEAD BacLight viability stain (Molecular Probes Europe BV, Leiden, The Netherlands) differentiated between live and dead bacteria within the biofilms, and extracellular polymeric substances (slime) from the biofilms was evaluated after staining with calcofluor white (Sigma Chemical Company, Rocky Hill, New Jersey). Human β-defensin 3 and clindamycin reduced the S aureus biofilm area. Human β-defensin 3 was significantly more effective against bacteria from the S aureus biofilms than was clindamycin. Vancomycin did not reduce the S aureus biofilm area.

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.

In this study, the difference in expression of human beta-defensin-3 in periprosthetic tissue and cancellous bone was observed in the periprosthetic tissue and cancellous bone of patients in the periprosthetic joint infection group, the aseptic loosening group, and the spacer treatment group as well as the synovial membrane and ilium of the normal control group. Hematoxylin and eosin staining of the synovial tissue showed different levels of neutrophil infiltration in all groups except for the normal control group. Immunofluorescence staining of periprosthetic tissue and cancellous bone showed the most positive cells expressing human beta-defensin-3 and the largest mean optical density in the periprosthetic joint infection group, followed by the aseptic loosening group, the spacer treatment group, and the normal control group, with a significant difference in comparison between the periprosthetic joint infection group and the other 3 groups (P<.01). White blood cell count, erythrocyte sedimentation rate, and C-reactive protein level were highest in the periprosthetic joint infection group, whereas no difference was found between the other 3 groups. Taken together, high levels of human beta-defensin-3 protein expression were found in the periprosthetic tissue and cancellous bone of patients with periprosthetic joint infection and aseptic loosening, but there are differential expressions of human beta-defensin-3, and this may provide a new marker for the differential diagnosis of infection and loosening of the artificial joint.

A highly unstable and neurological injury, the isolated U-shaped sacral fracture without pre-pelvic ring fracture but combined with cauda equina injury is rare in clinics, and the treatment method remains unclear. It can occur when patients fall from a height, the lower extremities hit the ground in extreme flexion, and the sacrum is the direct touchdown point. The direct impact on the sacrum and the vertical extrusion energy through the spinal column may be the main mechanism of injury. The U-shaped sacral fracture is easily missed, and diagnosis is often delayed as it is difficult to detect on anteroposterior view pelvic radiograph due to angulation of the fracture and bowel shadow. When clinical signs suggested a possible U-shaped sacral fracture, a 2- to 3-mm cut computed tomography scan with coronal and sagittal reconstruction can provide optimal imaging to identify and evaluate the sacral fracture.This article describes 2 patients, a 16-year-old girl and a 40-year-old man, with U-shaped sacral fractures. The patients were treated with posterior sacral laminectomy within 1 week after injury and achieved satisfactory postoperative recovery. Follow-up showed bony union with no further displacement or internal fixation failure, wound infection, delayed healing, or compression of the skin by the plate and screws. The results show that posterior vertebral plate decompression and reconstructive plate internal fixation can obtain a satisfactory outcome with minor operation trauma and few complications.