To design slow resorption patient-specific bone graft whose properties of bone regeneration are increased by its geometry and composition and to assess it in in-vitro and in-vivo models.

A graft composed by hydroxyapatite (HA) and β-TCP was designed as a cylinder with 3D gyroid porosities and 7 mm medullary space based on swine's anatomy. It was produced using a stereolithography 3D-printing machine (V6000, Prodways).

Sterile bone grafts impregnated with or without a 10µg/mL porcine BMP-2 (pBMP-2) solution were implanted into porcine femurs in a bone loss model. Bone defect was bi-weekly evaluated by X-ray during 3 months. After sacrifice, microscanner and non-decalcified histology analysis were conducted on biopsies.

Finally, osteoblasts were cultured inside the bone graft or in monolayer underneath the bone graft. Cell viability, proliferation, and gene expression were assessed after 7 and 14 days of cell culture (n=3 patients).

3D scaffolds were successfully manufactured with a composition of 80% HA and 20% β-TCP ±5% with indentation compressive strength of 4.14 MPa and bending strength of 11.8MPa.

In vivo study showed that bone regeneration was highly improved in presence of pBMP-2. Micro-CT shows a filling of the gyroid sinuses of the implant (Figure 1).

In vitro, the presence of BMP2 did not influence the viability of the osteoblasts and the mortality remained below 3%. After 7 days, the presence of BMP2 in the scaffold significantly increased by 85 and 65% the COL1A1 expression and by 8 and 33-fold the TNAP expression by osteoblasts in the monolayer or in the scaffold, respectively. This BMP2 effect was transient in monolayer and did not modify gene expression at day 14.

BMP2-impregnated bone graft is a promising patient-personalized 3D-printed solution for bone defect regeneration, by promoting neighboring host cells recruitment and solid new bone formation.

For any figures and tables, please contact the authors directly.

Decellularization techniques have advanced to reduce the risk of immune rejection in transplantation. Validation of these protocols typically relies on Crapo's criteria¹, which include the absence of visible nuclei and low DNA content. In our study, five decellularization protocols were compared to determine the optimal approach for human fascia lata (HFL) samples. However, our findings raised questions as to why recipients can still develop immunity despite meeting validation criteria.

HFL samples were decellularized using four protocols with SDS-Triton X100-DNase (D1 to D4-HFL) and one protocol using solvent-detergent-based baths (D5-HFL). The decellularized samples (D-HFL) were compared to native samples (N-HFL) using histology, and DNA content was measured. The human leukocyte antigen (HLA) content within the matrix was assessed using western blot analysis. Both D-HFL and N-HFL samples, along with negative control patches, were implanted in the backs of 28 Wistar rats. Anti-human IgG serum levels were evaluated after one month.

H&E and Hoechst staining revealed the absence of residual cells in all decellularization protocols. DNA content was consistently below the critical threshold (p<0.05). All implanted D-HFL samples resulted in significantly lower anti-human IgG levels compared to N-HFL (p<0.01). However, 2.5 out of 4 rats developed immunity after being implanted with D1 to D4-HFL, with varying levels of anti-human IgG. Only rats implanted with D5-HFL showed undetectable levels of IgG and were considered non-immunized. Western blot analysis indicated that only D5-HFL had a residual HLA content below 1%.

The literature on decellularization has primarily relied on Crapo's criteria, which do not consider the role of HLA mismatch in acute immune rejection. Our results suggest that a residual HLA content below 1% should also be considered to prevent immunization, even if other validation criteria are met. Further research is needed to evaluate the impact of residual HLA levels on human allotransplantation outcomes.

Aim

Local antibiotics released through a carrier is a commonly used technique to prevent infection in orthopaedic procedures. An interesting carrier in aseptic bone reconstructive surgery are bone chips impregnated with AB solution. Systemically administered Cefazolin (CFZ) is used for surgical site infection prophylaxis however in vitro study showed that fresh frozen and processed bone chips impregnated with CFZ solution completely release the CFZ within a few hours. On the other hand irradiated freeze-dried bone chips, treated with supercritical CO2 (scCO2) have been shown to be an efficient carrier for the antibiotics vancomycine or tobramycine.

With this pilot study we wanted to investigate if CFZ solution impregnation of bone chips treated with scCO2 shows a more favorable release pattern of CFZ.

The purpose of this study is to enhance massive bone allografts osseointegration used to reconstruct large bone defects. These allografts show >50% complication rate requiring surgical revision in 20% cases. A new protocol for total bone decellularisation exploiting the vasculature can offer a reduction of postoperative complication by annihilating immune response and improving cellular colonization/ osseointegration.

The nutrient artery of 18 porcine bones - humerus/femur/radius/ulna - was cannulated. The decellularization process involved immersion and sequential perfusion with specific solvents over a course of one week. Perfusion was realized by a peristaltic pump (mean flow rate: 6ml/min). The benefit of arterial perfusion was compared to a control group kept in immersion baths without perfusion.

Bone samples were processed for histology (HE, Masson's trichrome and DAPI for cell detection), immunohistochemistry (IHC : Collagen IV/elastin for intraosseous vascular system evaluation, Swine Leukocyte Antigen – SLA for immunogenicity in addition to cellular clearance) and DNA quantification. Sterility and solvent residues in the graft were also evaluated with thioglycolate test and pH test respectively.

Compared to native bones, no cells could be detected and residual DNA was <50ng/mg dry weight. Intramedullary spaces were completely cleaned. IHC showed the preservation of intracortical vasculature with channels bounded by Collagen IV and elastin within Haversian systems. IHC also showed a significant decrease in SLA signaling. All grafts were sterile at the last decellularization step and showed no solvent residue. The control group kept in immersion baths, paired with 6 perfused radii/ulnae, showed that the perfusion is mandatory to ensure complete decellularisation.

Our results prove the effectiveness of a new concept of total bone decellularisation by perfusion. These promising results could lead to a new technique of Vascularized Composite Allograft transposable to pre-clinical and clinical models.

Introduction

The surgical management of late PJI was usually done in two stages with the placement of a temporary cement spacer. The development of one-stage surgical care raises questions about the two-stage strategy. The objectives of this study are to identify the complications related to the presence of the cement spacer within a two-stage strategy. The septic recurrence rate is also evaluated after a minimum follow-up of two years.

Aim

We wonder what the results of two stage procedures were in terms of morbidity (amputation, dead) and infection recurrence. We also seek to identify risk factors for failure and see if the results of a second two stage surgery were not even worse.

Introduction

The management of patients with open leg fracture in Ivory Coast does not meet the standards of developed countries due to socio-economic conditions, accessibility and organization of care. However, is this care problematic? Is it associated with more post-traumatic infection or mechanical complications and are these correlated with the delay for treatment and the method of treatment?

Aim

Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality, 20–30 % risk of infection in patient with implant related infection (IRI) .18F-FDG PET/CT is helpful in the management of SAB, leading to detection of more metastatic foci and treatment modification and finally decrease relapses and mortality rate. Our objective was to analyze mortality in high risk SAB patients undergoing 18F-FDG PET/CT and to see whether it's use in patients with IRI reduced their mortality.

Aim

Apart from other biomarkers isolated in the synovial fluid, alpha-defensin appears to be a promising diagnostic tool to confirm a periprosthetic joint infection (PJI) in the hip or knee. The purpose of this study was to evaluate the sensitivity and specificity of an alpha defensin lateral flow (ADLF) test compared to usual standard classifications in the diagnostic management of PJI.

Aim

Our study aimed to analyze 1) the prevalence of peripheral arterial disease (PAD) and infection in diabetic patients with and without Charcot foot (CF), 2) the characteristics of PAD in these 2 groups, 3) the prognosis of patients with CF and PAD and/or infection.

Aim

Irrigation is a major step during debridement surgery in the context of Prosthetic Joint Infections (PJI), but its effects on biofilms are poorly described.

The present study aims at evaluating the effect of PW alone or followed by antibiotics on MSSA and MRSA biofilms grown on Ti6Al4V coupons in-vitro.

Background

DAIR is an attractive treatment for PJI. The purpose of this study is to determine predictive factors of failure.

Aims

Low haemoglobin (Hb) at admission has been identified as a risk factor for mortality for elderly patients with hip fractures in some studies. However, this remains controversial. This study aims to analyze the association between Hb level at admission and mortality in elderly patients with hip fracture undergoing surgery.

Aim

The treatment of a chronic prosthetic joint infection (PJI) is a combination of the bacteria's identification, a «carcinological» surgery and an appropriate antibiotherapy. In case of gram positive cocci infection, rifampicin is often used.

The aim of this study is to determine which factors are responsible for the development of resistance to rifampicine.

Aims

The purpose of this current multicentre study is to analyse the presence of alpha-defensin proteins in synovial fluid using the Synovasure lateral flow device and to determine its diagnostic reliability and accuracy compared with the prosthetic joint infection (PJI) criteria produced by the Musculoskeletal Infection Society (MSIS).

Aim

Bacterial identification in musculoskeletal infection is sometimes difficult and treatment strategy difficult facing unknown pathogen agent. We wonder if the delay of incubation and the preservation conditions of the samples between surgical procurement and subculture on plates have an influence.

Introduction

Patient satisfaction after total hip arthroplasty (THA) has been reported to be significantly better than after total knee arthroplasty (TKA). The same has been observed for the capacity to forget during daily life activities about the operated joint. Recently a new patient reported outcome score, the Forgotten Joint Score (FJS-12) a twelve item questionaire, has been used to evaluate postoperative outcome in joint arthroplasty. A better FJS-12 score was measured in THA than in TKA objectivating the intuitive feeling that the joint was more forgotten in THA than in TKA.

Discussion: Total ankle replacement shows continuous progress. Many implants are proposed to the surgeon. The purpose of this study is to evaluate the matching between the components and the anatomy on different levels of tibial cut.

Methods: 18 cadaveric distal tibias were cut at a distance of 0, 3, 6 and 9 mm from the joint space. The mediolateral and anteroposteriror length were measured; and the surface as well. These same measurements were performed to the tibial components of 5 different prosthesis (AES®, Hintegra®, Mobility®, Salto®, Star®). For each tibial cut, we selected tibial components that matched the mediolateral length. Then, these components were classified in function of their anterioposterior matching for the different levels of cut.

Results: We showed that some components are more universal than the others because of a maximal contact surface and an anteroposterior cortical support.

Conclusion: The longevity of the TAA depends on the stress forces, the matching surface, the components coating and the bone quality. This is a preliminary study wich certainly needs to take into consideration with others factors like occurrence or absence of stabilizing keel and differents methods of component fixation.

Bone allografts can be used in any kind of surgery involving bone from minor defects to major bone loss after tumour resection. This review describes the various types of bone grafts and the current knowledge on bone allografts, from procurement and preparation to implantation. The surgical conditions for optimising the incorporation of bone are outlined, and surgeon expectations from a bone allograft discussed.