Infections in orthopaedic surgery : clinical and experimental studies

The diagnostic difficulties, variability in outcome and the heterogeinity of the problem of orthopaedic infections stimulated the author to a study of the literature, and several clinical and experimental studies. The diagnosis prosthesis-related infection can only be reached with an acceptable degree of certainty by combination of clinical, laboratory and imaging investigations. Fourty-seven patients with a prosthetic hip infection treated in our hospital were retrospectively divided into three treatment groups: I debridement and retention of the original components, II resection arthroplasty and III removal of the prosthesis followed by immediate or staged reimplantation. Two patiens died because of the infection. The infection was succesfully eradicated initially in 44%, 73% and 94% of the patients, respectively. Removal of the prosthesis is superior for eradication of the infection, but the functional outcome of the resection arthroplasty is poor. For better functional results, an exchange of the prosthesis, when possible, is advised. To emphasise the haematogenous route as an important pathway for orthopaedic infections, a retrospective analysis of 28 children with an osteomyelitis was performed. The patients were evaluated by chart review. All children were treated surgically and treated with antibiotics subsequently. In addition to surgical intervention, six weeks of antibiotic therapy appears to be sufficient to eradicate acute as well as chronic osteomyelitis in children. In a clinical case report the development and course of a haematogenous hip prosthesis infection after an acute cholecystitis is described. A Clostridium perfringens was isolated from the infected gallbladder and after several months of the prosthesis. If patiens of a total joint prosthesis develop bacterial infections at distant sites, they should be treated immediately and aggresively with antibiotics to prevent haematogenous spread to the prosthetic joint. The so-called "race for the surface" theory, as postulated by Gristina, suggests competition between tissue and bacterial cells for implant material surfaces. If bacteria arrive first at the surface and colonise the biomaterial, an infection will develop. In an experimental animal study the question whether there is a difference in infection suspectibility of two common orthopaedic implant surfaces with a different biocompatibility (grit-blasted Ti6A14V and hydroxyapatite coated Ti6A14V) was addressed. Prior to implantation the left tibia of a rabbit was contaminated with increasing concentrations of Staphylococcus aureus. After sacrifice, bone adjecent to the implant was harvested for bacteriological, histological and histomorphometrical examination and quantification. Bacteriology and histology showed more severe infection for the HA implants as compared to the Ti implants. Histomorphometry confirms a relationship between implant loosening and infection. The results suggest that the "race for the surface theory" should be reconsidered for the more complex in vivo situation. Also the development of an experimental animal model to study haematogenous infections of cementless implants is described. A cylindrical Ti6A14V or hydroxyapatite coated Ti6A14V implant was inserted into the right tibia of rabbits. After at least 4 weeks, the implants were contaminated through selective angiography with varying doses of Staphylococcus aureus (Wood 46). After sacrifice, at least after 1 week, biopsies of bone were cultured. Injection of 5x10 8 colony forming units caused positive cultures in all cases and minimal systemetic reactions. This model is used for further studies of haematogenous implant infections

The Role of Negative-Pressure Wound Therapy in Patients with Fracture-Related Infection:A Systematic Review and Critical Appraisal

INTRODUCTION: Fracture-related infection (FRI) is a severe musculoskeletal complication in orthopedic trauma surgery, causing challenges in bony and soft tissue management. Currently, negative-pressure wound therapy (NPWT) is often used as temporary coverage for traumatic and surgical wounds, also in cases of FRI. However, controversy exists about the impact of NPWT on the outcome in FRI, specifically on infection recurrence. Therefore, this systematic review qualitatively assesses the literature on the role of NPWT in the management of FRI. METHODS: A literature search of the PubMed, Embase, and Web of Science database was performed. Studies that reported on infection recurrence related to FRI management combined with NPWT were eligible for inclusion. Quality assessment was done using the PRISMA statement and the Newcastle-Ottawa Quality Assessment Scale. RESULTS: After screening and quality assessment of 775 unique identified records, eight articles could be included for qualitative synthesis. All eight studies reported on infection recurrence, which ranged from 2.8% to 34.9%. Six studies described wound healing time, varying from two to seven weeks. Four studies took repeated microbial swabs during subsequent vacuum dressing changes. One study reported newly detected pathogens in 23% of the included patients, and three studies did not find new pathogens. CONCLUSION: This review provides an assessment of current literature on the role of NPWT in the management of soft tissue defects in patients with FRI. Due to the lack of uniformity in included studies, conclusions should be drawn with caution. Currently, there is no clear scientific evidence to support the use of NPWT as definitive treatment in FRI. At this stage, we can only recommend early soft tissue coverage (within days) with a local or free flap. NPWT may be safe for a few days as temporarily soft tissue coverage until definitive soft tissue management could be performed. However, comparative studies between NPWT and early wound closure in FRI patients are needed

Antibacterial and anti-inflammatory properties of host defense peptides against Staphylococcus aureus

Cationic host defense peptides (HDPs) are a promising alternative to antibiotics in the fight against Staphylococcus aureus infections. In this study, we investigated the antibacterial and immunomodulatory properties of three HDPs namely IDR-1018, CATH-2, and LL-37. Although all three HDPs significantly inhibited LPS-induced activation of human macrophages, only CATH-2 prevented S. aureus growth. When applied to different infection models focused on intracellularly surviving bacteria, only IDR-1018 showed a consistent reduction in macrophage bacterial uptake. However, this observation did not correlate with an increase in killing the efficiency of intracellular S. aureus. Here, we conclude that despite the promising antibacterial and anti-inflammatory properties of the selected HDPs, macrophages' intrinsic antibacterial functions were not improved. Future studies should either focus on combining different HDPs or using them synergistically with other antibacterial agents to improve immune cells' efficacy against S. aureus pathogenesis

Guideline for management of septic arthritis in native joints (SANJO).

This clinical guideline is intended for use by orthopedic surgeons and physicians who care for patients with possible or documented septic arthritis of a native joint (SANJO). It includes evidence and opinion-based recommendations for the diagnosis and management of patients with SANJO

Human monoclonal antibodies against Staphylococcus aureus surface antigens recognize in vitro and in vivo biofilm

Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and potential treatment of biofilm-related infections. Here, we show that mAbs targeting common surface components of S. aureus can recognize clinically relevant biofilm types. The mAbs were also shown to bind a collection of clinical isolates derived from different biofilm-associated infections (endocarditis, prosthetic joint, catheter). We identify two groups of antibodies: one group that uniquely binds S. aureus in biofilm state and one that recognizes S. aureus in both biofilm and planktonic state. Furthermore, we show that a mAb recognizing wall teichoic acid (clone 4497) specifically localizes to a subcutaneously implanted pre-colonized catheter in mice. In conclusion, we demonstrate the capacity of several human mAbs to detect S. aureus biofilms in vitro and in vivo

Prevention : T

Joint replacement is a successful surgical procedure that provides pain relief, restores joint function and improves the quality of life of patients. A minority of patients will experience complications like aseptic failure or prosthetic joint infection (PJI; Tande and Patel 2014)

Recommendations on diagnosis and antimicrobial treatment of infections after anterior cruciate ligament reconstruction (ACL-R) endorsed by ESSKA and EBJIS

Infection after anterior cruciate ligament reconstruction (ACL-R) is a rare but devastating complication affecting predominantly young and sportive individuals. A timely and correct diagnosis as well as optimized management is paramount to circumvent serious sequelae and compromise in life quality. These recommendations are primarily intended for use by infectious disease specialists and microbiologists, but also orthopedic surgeons and other healthcare professionals who care for patients with infections after ACL-R. They are based on evidence mainly originating from observational studies and opinions of experts in the field, and cover the management of infections after ACL-R with a special focus on etiology, diagnosis, antimicrobial treatment and prevention. Comprehensive recommendations on surgical treatment and rehabilitation are presented separately in a document primarily addressing orthopedic professionals

An uncemented iso-elastic monoblock acetabular component : Preliminary results

Little is known about the clinical application of highly cross-linked polyethylene (HXLPE) blended with vitamin E. This study evaluates an uncemented iso-elastic monoblock cup with vitamin E blended HXLPE. 112 patients were followed up for 2. years. 95.5% completed the follow-up. The mean VAS score for patient satisfaction was 8.8 and the mean Harris Hip Score was 94.2. In 7 cases initial gaps behind the cup were observed, which disappeared completely during follow-up in 6 cases. The mean femoral head penetration rate was 0.055. mm/year. No adverse reactions or abnormal mechanical behavior was observed with the short term use of vitamin E blended HXLPE. This study shows the promising performance of this cup and confirms the potential of vitamin E blended HXLPE