Global Forum: The Burden of Bone and Joint Infections: A Growing Demand for More Resources

Global, regional, and national burden of other musculoskeletal disorders, 1990-2020, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021

Background

Musculoskeletal disorders include more than 150 different conditions affecting joints, muscles, bones, ligaments, tendons, and the spine. To capture all health loss from death and disability due to musculoskeletal disorders, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) includes a residual musculoskeletal category for conditions other than osteoarthritis, rheumatoid arthritis, gout, low back pain, and neck pain. This category is called other musculoskeletal disorders and includes, for example, systemic lupus erythematosus and spondylopathies. We provide updated estimates of the prevalence, mortality, and disability attributable to other musculoskeletal disorders and forecasted prevalence to 2050.

Methods

Prevalence of other musculoskeletal disorders was estimated in 204 countries and territories from 1990 to 2020 using data from 68 sources across 23 countries from which subtraction of cases of rheumatoid arthritis, osteoarthritis, low back pain, neck pain, and gout from the total number of cases of musculoskeletal disorders was possible. Data were analysed with Bayesian meta-regression models to estimate prevalence by year, age, sex, and location. Years lived with disability (YLDs) were estimated from prevalence and disability weights. Mortality attributed to other musculoskeletal disorders was estimated using vital registration data. Prevalence was forecast to 2050 by regressing prevalence estimates from 1990 to 2020 with Socio-demographic Index as a predictor, then multiplying by population forecasts.

Findings

Globally, 494 million (95% uncertainty interval 431-564) people had other musculoskeletal disorders in 2020, an increase of 123·4% (116·9-129·3) in total cases from 221 million (192-253) in 1990. Cases of other musculoskeletal disorders are projected to increase by 115% (107-124) from 2020 to 2050, to an estimated 1060 million (95% UI 964-1170) prevalent cases in 2050; most regions were projected to have at least a 50% increase in cases between 2020 and 2050. The global age-standardised prevalence of other musculoskeletal disorders was 47·4% (44·9-49·4) higher in females than in males and increased with age to a peak at 65-69 years in male and female sexes. In 2020, other musculoskeletal disorders was the sixth ranked cause of YLDs globally (42·7 million [29·4-60·0]) and was associated with 83 100 deaths (73 600-91 600).

Interpretation

Other musculoskeletal disorders were responsible for a large number of global YLDs in 2020. Until individual conditions and risk factors are more explicitly quantified, policy responses to this burden remain a challenge. Temporal trends and geographical differences in estimates of non-fatal disease burden should not be overinterpreted as they are based on sparse, low-quality data.

Funding

Bill & Melinda Gates Foundation.

Antimicrobial Stewardship for Outpatients with Chronic Bone and Joint Infections in the Orthopaedic Clinic of an Academic Tertiary Hospital, South Africa

Bone and joint infections are associated with prolonged hospitalizations, high morbidity and complexity of care. They are difficult to treat, and successful therapy requires organism-specific antimicrobial therapy at high doses for a prolonged duration as recommended in standard treatment guidelines (STGs). Adherence to the treatment plan is equally important, which is enhanced with knowledge of the condition as well as appropriate antibiotics. Consequently, the aim of this study was to provide antimicrobial stewardship (AMS) services to outpatients with chronic bone and joint infections presenting to the orthopaedic clinic at a public South African tertiary hospital. A total of 44 patients participated in this study. Chronic osteomyelitis was diagnosed in 39 (89%) patients and septic arthritis in 5 (11%). The majority (43%) of infections were caused by Staphylococcus aureus followed by Pseudomonas aeruginosa (14%). Seventy-one antibiotics were prescribed at baseline with rifampicin prescribed the most (39%), followed by ciprofloxacin (23%). The majority (96%) of the antibiotics were not prescribed according to the South African STG; however, interventions were only needed in 31% of prescribed antibiotics (n = 71) since the STG only recommends empiric therapy directed against Staphylococcus aureus. Seventy-seven percent of the patients obtained a high self-reported adherence score at baseline. Consequently, there is a need to improve AMS in bone and joint infections to improve future care.

Implantable biomedical materials for treatment of bone infection

The treatment of bone infections has always been difficult. The emergence of drug-resistant bacteria has led to a steady decline in the effectiveness of antibiotics. It is also especially important to fight bacterial infections while repairing bone defects and cleaning up dead bacteria to prevent biofilm formation. The development of biomedical materials has provided us with a research direction to address this issue. We aimed to review the current literature, and have summarized multifunctional antimicrobial materials that have long-lasting antimicrobial capabilities that promote angiogenesis, bone production, or "killing and releasing." This review provides a comprehensive summary of the use of biomedical materials in the treatment of bone infections and a reference thereof, as well as encouragement to perform further research in this field.

The tale of microencapsulated rifampicin: is it useful for the treatment of periprosthetic joint infection?

Purpose

Microencapsulation techniques have allowed the addition of rifampicin to bone cement, but its in vivo efficacy has not been proven. The aim of our study is to determine the superiority of cement containing gentamicin and rifampicin microcapsules in the treatment of PJI versus cement exclusively containing gentamicin.

Methods

An S. aureus PJI was induced in 15 NZW rabbits. A week after inoculation, the first stage of replacement was carried out, and the animals were divided into two groups: group R received a spacer containing gentamicin and rifampicin microcapsules, and group C received a spacer containing gentamicin. Intra-articular release curve of rifampicin and infection and toxicity markers were monitored for four weeks post-operatively, when microbiological analysis was performed.

Results

The microbiological cultures showed a significantly lower growth of S. aureus in soft tissue (2.3·10⁴ vs 0; p = 0.01) and bone (5.7·10² vs 0; p = 0.03) in the group with rifampicin microcapsules. No differences were found in systemic toxicity markers. Rifampicin release from the cement spacer showed higher concentrations than the staphylococcal MIC throughout the analysis.

Conclusion

The in vivo analyses demonstrated the superiority of cement containing gentamicin and rifampicin microcapsules versus the isolated use of gentamicin in the treatment of PJI in the rabbit model without serious side effects due to the systemic absorption of rifampicin. Given the increasing incidence of staphylococci-related PJI, the development of new strategies for intra-articular administration of rifampicin for its treatment has a high clinical impact.

Bone and Joint Infections: The Role of Imaging in Tailoring Diagnosis to Improve Patients' Care

Imaging is needed for the diagnosis of bone and joint infections, determining the severity and extent of disease, planning biopsy, and monitoring the response to treatment. Some radiological features are pathognomonic of bone and joint infections for each modality used. However, imaging diagnosis of these infections is challenging because of several overlaps with non-infectious etiologies. Interventional radiology is generally needed to verify the diagnosis and to identify the microorganism involved in the infectious process through imaging-guided biopsy. This narrative review aims to summarize the radiological features of the commonest orthopedic infections, the indications and the limits of different modalities in the diagnostic strategy as well as to outline recent findings that may facilitate diagnosis.

Synthesis and Characterization of Bone Binding Antibiotic-1 (BBA-1), a Novel Antimicrobial for Orthopedic Applications

Osteomyelitis and orthopedic infections are major clinical problems, limited by a lack of antibiotics specialized for such applications. In this paper, we describe the design and synthesis of a novel bone-binding antibiotic (BBA-1) and its subsequent structural and functional characterization. The synthesis of BBA-1 was the result of a two-step chemical conjugation of cationic selective antimicrobial-90 (CSA-90) and the bisphosphonate alendronate (ALN) via a heterobifunctional linker. This was analytically confirmed by HPLC, FT-IR, MS and NMR spectroscopy. BBA-1 showed rapid binding and high affinity to bone mineral in an in vitro hydroxyapatite binding assay. Kirby—Baur assays confirmed that BBA-1 shows a potent antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus comparable to CSA-90. Differentiation of cultured osteoblasts in media supplemented with BBA-1 led to increased alkaline phosphatase expression, which is consistent with the pro-osteogenic activity of CSA-90. Bisphosphonates, such as ALN, are inhibitors of protein prenylation, however, the amine conjugation of ALN to CSA-90 disrupted this activity in an in vitro protein prenylation assay. Overall, these findings support the antimicrobial, bone-binding, and pro-osteogenic activities of BBA-1. The compound and related agents have the potential to ensure lasting activity against osteomyelitis after systemic delivery.

Development of a large animal rabbit model for chronic periprosthetic joint infection

Aims

Periprosthetic joint infections (PJIs) and osteomyelitis are clinical challenges that are difficult to eradicate. Well-characterized large animal models necessary for testing and validating new treatment strategies for these conditions are lacking. The purpose of this study was to develop a rabbit model of chronic PJI in the distal femur.

Methods

Fresh suspensions of Staphylococcus aureus (ATCC 25923) were prepared in phosphate-buffered saline (PBS) (1 × 10⁹ colony-forming units (CFUs)/ml). Periprosthetic osteomyelitis in female New Zealand white rabbits was induced by intraosseous injection of planktonic bacterial suspension into a predrilled bone tunnel prior to implant screw placement, examined at five and 28 days (n = 5/group) after surgery, and compared to a control aseptic screw group. Radiographs were obtained weekly, and blood was collected to measure ESR, CRP, and white blood cell (WBC) counts. Bone samples and implanted screws were harvested on day 28, and processed for histological analysis and viability assay of bacteria, respectively.

Results

Intraosseous periprosthetic introduction of planktonic bacteria induced an acute rise in ESR and CRP that subsided by day 14, and resulted in radiologically evident periprosthetic osteolysis by day 28 accompanied by elevated WBC counts and histological evidence of bacteria in the bone tunnels after screw removal. The aseptic screw group induced no increase in ESR, and no lysis developed around the implants. Bacterial viability was confirmed by implant sonication fluid culture.

Conclusion

Intraosseous periprosthetic introduction of planktonic bacteria reliably induces survivable chronic PJI in rabbits.

Cite this article: Bone Joint Res 2021;10(3):156–165.

High-Throughput Metagenomics for Identification of Pathogens in the Clinical Settings

The application of sequencing technology is shifting from research to clinical laboratories owing to rapid technological developments and substantially reduced costs. However, although thousands of microorganisms are known to infect humans, identification of the etiological agents for many diseases remains challenging as only a small proportion of pathogens are identifiable by the current diagnostic methods. These challenges are compounded by the emergence of new pathogens. Hence, metagenomic next-generation sequencing (mNGS), an agnostic, unbiased, and comprehensive method for detection, and taxonomic characterization of microorganisms, has become an attractive strategy. Although many studies, and cases reports, have confirmed the success of mNGS in improving the diagnosis, treatment, and tracking of infectious diseases, several hurdles must still be overcome. It is, therefore, imperative that practitioners and clinicians understand both the benefits and limitations of mNGS when applying it to clinical practice. Interestingly, the emerging third-generation sequencing technologies may partially offset the disadvantages of mNGS. In this review, mainly: a) the history of sequencing technology; b) various NGS technologies, common platforms, and workflows for clinical applications; c) the application of NGS in pathogen identification; d) the global expert consensus on NGS-related methods in clinical applications; and e) challenges associated with diagnostic metagenomics are described.

Epidemiology of complex bone and joint infections in France using a national registry: The CRIOAc network

OBJECTIVES

In France, a network of reference centers for bone and joint infections (BJI) was created in 2008, focused on the management of complex BJI (previous failure, difficult-to-treat microorganisms, heavy comorbidities or surgical procedures). A national registry was implemented from 2012, collecting decisions advised in periodic multidisciplinary meetings. We present here an epidemiological overview.

METHODS

All consecutive adult patients presented from 2014 to 2019 in 23/30 reference centers were included in this cohort. Characteristics of patients, BJI, and medico-surgical management advice were described.

RESULTS

27,483 individual patients were included, corresponding to 28,365 distinct infectious episodes, which 17,328 were complex. Median age was 65 years, with 62% of men, 1/3 patients presented more than 2 comorbidities. Prosthetic joint infections (PJI) represented 42% of all BJIs (11,812 episodes). Staphylococcus aureus, coagulase-negative staphylococci and polymicrobial PJI represented 26%, 25% and 16% respectively. DAIR (debridement, antibiotics and implant retention) was proposed for 3,157 (27%), whereas one-stage and two-stage revision for 3,683 (31%) and 1,764 (15%). An antibiotic treatment was advised in 10,493 episodes (87%), with combination therapy in 88%.

CONCLUSION

This national network allows an optimized management of complex BJIs. Its cohort is a unique opportunity to draw up a detailed epidemiological picture and to follow the trends of these infrequent infections.

Effect of referral systems on costs and outcomes after hip fracture surgery in Taiwan

OBJECTIVE

To explore the economic burdens of hip fracture surgery in patients referred to lower-level medical institutions and to evaluate how referral systems affect costs and outcomes of hip fracture surgery.

DESIGN

A nationwide population-based retrospective cohort study.

SETTING

All hospitals in Taiwan.

PARTICIPANTS

A total of 7500 patients who had received hip fracture surgery (International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) diagnostic codes 820.0 ∼ 820.9 and procedure codes 79.15, 79.35, 81.52, 81.53) performed in 1997 to 2013.

MAIN OUTCOME MEASURES

Total costs including outpatient costs, inpatient costs and total medical costs and medical outcomes including 30-day readmission, 90-day readmission, infection, dislocation, revision and mortality.

RESULTS

The patients were referred to a lower medical institution after hip fracture surgery (downward referral group) and 3034 patients continued treatment at the same medical institution (non-referral group). Demographic characteristics, clinical characteristics and institutional characteristics were significantly associated with postoperative costs and outcomes (P < 0.05). On average, the annual healthcare cost was New Taiwan Dollars (NT$)2262 per patient lower in the downward referral group compared with the non-referral group. The annual economic burdens of the downward referral group approximated NT$241 million (2019 exchange rate, NT$30.5 = US$1).

CONCLUSIONS

Postoperative costs and outcomes of hip fracture surgery are related not only to demographic and clinical characteristics, but also to institutional characteristics. The advantages of downward referral after hip fracture surgery can save huge medical costs and provide a useful reference for healthcare authorities when drafting policies for the referral system.

Computerized registry as a potential tool for surveillance and management of complex bone and joint infections in France: French registry of complex bone and joint infections

Aims

The French registry for complex bone and joint infections (C-BJIs) was created in 2012 in order to facilitate a homogeneous management of patients presented for multidisciplinary advice in referral centres for C-BJI, to monitor their activity and to produce epidemiological data. We aimed here to present the genesis and characteristics of this national registry and provide the analysis of its data quality.

Methods

A centralized online secured database gathering the electronic case report forms (eCRFs) was filled for every patient presented in multidisciplinary meetings (MM) among the 24 French referral centres. Metrics of this registry were described between 2012 and 2016. Data quality was assessed by comparing essential items from the registry with a controlled dataset extracted from medical charts of a random sample of patients from each centre. Internal completeness and consistency were calculated.

Results

Between 2012 and 2016, 30,607 presentations in MM were recorded corresponding to 17,748 individual patients (mean age 62.1 years (SD 18.4); 10,961 (61.8%) males). BJI was considered as complex for 63% of cases (n = 19,355), and 13,376 (44%) had prosthetic joint infections (PJIs). The controlled dataset, available for 19 centres, included 283 patients. Global consistency and completeness were estimated at 88.2% and 88.9%, respectively, considering missing items in the eCRFs as negative results.

Conclusion

This national registry is one of the largest prospective databases on BJI and its acceptable data quality parameters allow further use for epidemiological purposes.Cite this article: Bone Joint Res 2020;9(9):635-644.

Musculoskeletal Infection in Orthopaedic Trauma: Assessment of the 2018 International Consensus Meeting on Musculoskeletal Infection

Fracture-related infections (FRIs) are among the most common complications following fracture fixation, and they have a huge economic and functional impact on patients. Because consensus guidelines with respect to prevention, diagnosis, and treatment of this major complication are scarce, delegates from different countries gathered in Philadelphia in July 2018 as part of the Second International Consensus Meeting (ICM) on Musculoskeletal Infection. This paper summarizes the discussion and recommendations from that consensus meeting, using the Delphi technique, with a focus on FRIs. A standardized definition that was based on diagnostic criteria was endorsed, which will hopefully improve reporting and research on FRIs in the future. Furthermore, this paper provides a grade of evidence (strong, moderate, limited, or consensus) for strategies and practices that prevent and treat infection. The grade of evidence is based on the quality of evidence as utilized by the American Academy of Orthopaedic Surgeons. The guidelines presented herein focus not only on the appropriate use of antibiotics, but also on practices for the timing of fracture fixation, soft-tissue coverage, and bone defect and hardware management. We hope that this summary as well as the full document by the International Consensus Group are utilized by those who are charged with musculoskeletal care internationally to optimize their management strategies for the prevention and treatment of FRIs.

Antimicrobial silver-coating for locking plates shows uneventful osteotomy healing and good biocompatibility results of an experimental study in rabbits

Infections after internal fixation of fractures remain a challenge. Silver is known for its antimicrobial activity, including activity against multi-resistant strains. The aim of the current study was to analyze the biocompatibility and potential influence on the osteotomy healing process of a silver-coating technology for locking plates compared to silver-free locking plates in an established rabbit model. The implants used in this study were 7-hole titanium locking plates, and plasma electrolytic oxidation (PEO) silver-coated equivalents. A total of 24 rabbits were used in this study (12 coated, 12 non-coated). An osteotomy of the midshaft of the humerus was created and the humerus stabilized with the 7-hole locking plates with a total of 6 screws. Radiographs were taken on day 0, week 2, 4, 6, 8, and 10 for continuous radiographical evaluation. All animals were euthanized after 10 weeks and further assessment was performed using X-rays, micro-CT, non-destructive four-point bending biomechanical testing and semi-quantitative histopathological evaluation. Furthermore, silver concentration was measured in the blood, kidney, liver, spleen, brain, feces and soft tissue around the plate. Radiographs showed normal undisturbed and completed healing of the osteotomy in all animals without any differences between the two groups over the entire observation period. Micro-CT analysis revealed overall tissue volume as well as tissue density to be comparable between the two groups. Mechanical testing showed comparable stiffness with an average stiffness relative to contralateral bones of 75.7 ± 16.1% in the silver-free control group compared to 69.7 ± 18.5% (p-value: 0.46). Semi-quantitative histopathological evaluation showed no remarkable difference in the analysis of the osteotomy gap healing or in the surrounding soft tissue area. There were detectable silver concentrations in the soft tissue around the plate after 10 weeks. Silver in the blood was only found in 3 animals within the first two weeks and all animals were free of silver afterwards. There were no detectable silver concentrations in the brain, liver, spleen, axillary lymph nodes and kidney. This study shows undisturbed osteotomy healing of the presented antimicrobial silver surface coating and a good biocompatibility in this rabbit model.

The Burden of Pediatric Musculoskeletal Diseases Worldwide

Global burden of disease (GBD) refers to the economic and human costs resulting from poor health. The disability-adjusted life year is a measure of life lost from premature death and life not lived at 100% health. Surgery has long been neglected in the distribution of resources for global health. Because of years of life lived with a disability and the large proportion of children in a population, pediatric musculoskeletal conditions early in life can contribute to the GBD. Fortunately, the World Health Organization has recently promoted essential surgical services through its Emergency and Essential Surgical Care Project and Global Initiative.

A new small animal model for simulating a two-stage-revision procedure in implant-related methicillin-resistant Staphylococcus aureus bone infection

BACKGROUND

Implant-related bone infections with methicillin-resistant Staphylococcus aureus (MRSA) remain a challenge for orthopedic surgeons. This devasting complication may lead to functional impairment and loss of the affected limbs. High failure rates in treatment make improvement of surgical treatment necessary. Beside an already established demanding and costly large animal model, a small animal model of a two-stage revision does not exist, yet. Thus, the purpose of this study was to establish a preclinical small animal model to simulate a two-stage revision in implant-related MRSA infection.

MATERIALS AND METHODS

In twelve rabbits Steel K-wires were implanted into the intramedullary canal of the left tibia, followed by inoculation with MRSA. Two different clinical isolates of MRSA-strains were used in two different concentrations (CFUs; 10⁵ and 10⁷ colony forming units (CFUs). This led to four groups of three rabbits each. Eleven rabbits survived the whole study period. After four weeks the inoculated K-wires were removed and replaced with vancomycin loaded PMMA-spacers (stage 1). Twenty-eight days later new K-wire implants were placed intramedullary (stage 2). After 84 days all animals were sacrificed. Tibiae were analyzed microbiologically, radiologically and histologically.

RESULTS

In every rabbit K-wire associated infection could be established within the first four weeks. After irrigation and debridement at revision one (stage 1), infection could be eradicated in 67% of group I, in 50% of group II and in 33% of group III and IV. Recurrence of the infection could be determined in all animals of group I and IV at day 84. X-ray analysis and histology both demonstrated clear signs of osteomyelitis after twelve weeks. Survival, clinical observations and weight assessment confirmed the ethical justifiable stress of the animals during the experiment.

CONCLUSION

The presented small animal model of a two-stage revision in implant-related infection is a promising preclinical set-up for assessment of new treatment strategies of implant-related infections. Both high survival as well as reinfection rates were possible by simulating the clinical gold standard of two-stage revision surgery in an MRSA implant-related infection model. Therefore, the model can be deemed suitable for further preclinical in vivo testing.

Health Care Costs of Post-traumatic Osteomyelitis in China: Current Situation and Influencing Factors

BACKGROUND

Currently, very limited information is available regarding the economic burdens of patients with extremity post-traumatic osteomyelitis (OM). This study aimed to investigate direct health care costs and utilization for inpatients with extremity post-traumatic OM and analyze its constituent ratios and influencing factors in Southern China.

METHODS

We searched in the electronic medical record system for inpatients who had received surgical interventions at our department between 2013 and 2016 for extremity post-traumatic OM. Data of direct health care costs incurred during their hospitalizations were collected in six main categories (service, diagnosis, treatment, materials, pharmaceuticals, and miscellaneous expenses). In addition, data of total medical costs for contemporaneous inpatients with non-post-traumatic OM were also collected as controls.

RESULTS

A total of 278 post-traumatic OM and 10,420 controls were included. The median cost for the post-traumatic OM inpatients was $10,504 US dollars, 4.8-fold higher than that for those with non-post-traumatic OM ($2189, P < 0.001). The direct cost in the category of materials accounted for the largest proportion (61%), followed by that in pharmaceuticals (12%) and treatment (11%). The median number of hospital admissions for post-traumatic OM patients was 1 time, with a median length-of-stay of 22 d. The most influencing factors for the health care costs of the post-traumatic OM inpatients were use of an external fixator ($16,016 for those who used versus $4956 for those who did not, P < 0.001), external fixator type ($19,563 for ring fixator versus $14,966 for rail fixator, P < 0.001), infection site ($13,755 for tibia, $14,216 for femur and $5673 for calcaneus, P < 0.001), and infection-associated injury type ($12,890 for infection after open fracture versus $8087 for infection after closed fracture, P = 0.001).

CONCLUSIONS

An unexpectedly large proportion of the direct health care costs for inpatients with extremity post-traumatic OM went to cover an external fixator, with expenses for pharmaceuticals and treatment accounting for only a little more than the tenth of the total health care costs. Use of external fixator, external fixator type, infection site, and infection-associated injury type directly influenced the health care costs.

Evaluation of bacterial presence on lead X-ray aprons utilised in the operating room via IBIS and standard culture methods

Background

Despite precautions, surgical procedures carry risk of infection. Radiation-protective lead aprons worn by operating personnel are a potential source of bacterial contamination and have not been fully evaluated.

Aim/objective

To evaluate lead aprons as a source of bacterial contamination, identify organisms most commonly found on this source, and devise a method with which to lower the risk of contamination.

Methods

In this basic science study, 20 randomly selected lead X-ray aprons were swabbed at three time points. The experimental treatment was with a hospital-grade disinfectant wipe. The samples were assessed for bacterial growth via traditional plating methods and mass spectrometry. Plates were graded on a scale of 0 to 4+ based on the number of quadrants with growth. Growth on one quadrant or more was considered contaminated.

Findings/results

Bacteria were initially detected via IBIS on a majority of the aprons (32/40), most commonly Staphylococcus epidermidis and Propionibacterium acnes. Virulent organisms cultured were Methicillin-resistant Staphylococcus epidermidis (MRSE), Neisseria, Streptococcus viridans and pseudomonas. MRSE were detected on 5/20 of the samples. Immediately after treatment, the majority of aprons showed less bacterial contamination (0/20 standard culture positive; 13/20 IBIS positive) with some recurrence at the 6-h time point (2/20 standard culture positive, 16/20 IBIS positive). All MRSE detected initially was eradicated.

Discussion

Lead X-ray aprons worn in the operating room harbour bacteria. Disinfecting before use may prevent the introduction of virulent organisms to patients. Our proposed method of sanitising with a disinfectant wipe is quick and effective.

3D printing in experimental orthopaedic surgery: do it yourself

INTRODUCTION

Periprosthetic infection is considered an increasing incidence pathology whose therapeutic strategies can be defined as unsatisfactory. Currently, animal models are employed to study its physiopathology and strategic therapies, but non-species-specific materials are implanted as foreign bodies. The use of these implants implies intrinsic instability, which hinders the development of a biofilm on their surfaces and complicates the post-operative recovery of the animal. The objective of the present study is the design of a species-specific implant for the New Zealand white (NZW) rabbit by means of 3D printing.

MATERIALS AND METHODS

A CT scan of the knee of a NZW rabbit was performed, and the tibial surface was reconstructed in order to fabricate a species-specific tibial plateau using Horos^® and Autodesk^® Meshmixer™ software. This implant was inserted in fifteen NZW rabbits, and the assessment of its stability was based on the position of the limb at rest and the animal weight-bearing capacity. Biofilm formation on the surface was demonstrated by crystal violet staining.

RESULTS

A 1.81 cm × 1 cm × 1.24 cm stainless steel implant was designed. It consisted of a 4-mm-thick tibial plate with a rough surface and an eccentric metaphyseal anchoring. All of the animals exhibited hyperflexion of the operated limb immediately post-operative, and 100% could apply full weight bearing from day 5 after surgery.

CONCLUSIONS

The species-specific design of implants in experimental surgery encourages rapid recovery of the animal and the development of a biofilm on their surfaces, making them ideal for the study of the physiopathology and for establishing possible therapeutic targets for prosthetic infection.