Intercalary diaphyseal endoprosthetic reconstruction for tibial septic non-union in an elderly patient: A case report

Medical innovations to maintain the function in patients with chronic PJI for whom explantation is not desirable: a pathophysiology-, multidisciplinary-, and experience-based approach

INTRODUCTION

PJI is the most dramatic complication after joint arthroplasty. In patients with chronic infection, prosthesis exchange is in theory the rule. However, this surgical approach is sometimes not desirable especially in elderly patients with multiple comorbidities, as it could be associated with a dramatic loss of function, reduction of the bone stock, fracture, or peroperative death. We propose here to report different approaches that can help to maintain the function in such patients based on a pathophysiology-, multidisciplinary-, and an experience-based approach.

METHODS

We describe the different points that are needed to treat such patients: (i) the multidisciplinary care management; (ii) understanding the mechanism of bacterial persistence; (iii) optimization of the conservative surgical approach; (iv) use of suppressive antimicrobial therapy (SAT); (v) implementation of innovative agents that could be used locally to target the biofilm.

RESULTS

In France, a nation-wide network called CRIOAc has been created and funded by the French Health ministry to manage complex bone and joint infection. Based on the understanding of the complex pathophysiology of PJI, it seems to be feasible to propose conservative surgical treatment such as "debridement antibiotics and implant retention" (with or without soft-tissue coverage) followed by SAT to control the disease progression. Finally, there is a rational for the use of particular agents that have the ability to target the bacteria embedded in biofilm such as bacteriophages and phage lysins.

DISCUSSION

This multistep approach is probably a key determinant to propose innovative management in patients with complex PJI, to improve the outcome.

CONCLUSION

Conservative treatment has a high potential in patients with chronic PJI for whom explantation is not desirable. The next step will be to evaluate such practices in nation-wide clinical trials.

[Robotics-mechanical bridge between imaging and patient]

BACKGROUND

There are still a high number of dissatisfied knee arthroplasty patients. This situation has not changed much for decades, despite many innovations focusing on implant longevity and higher procedural precision. In this context, there is a growing discussion on possible systematic errors made in knee arthroplasty, especially regarding the alignment philosophy of the implants.

OBJECTIVE

It was reported that a more anatomical alignment might result in improved patient outcome. However, current technologies have severe limitations to achieving optimized and individual alignment. In this context, the aim of this manuscript was to assess whether image-based robot-guided knee arthroplasty might represent an opportunity for achieving individualized alignment.

METHODS

The literature on this subject was evaluated and analyzed. Furthermore, research projects and expert recommendations were discussed.

RESULTS

The precision of preoperative planning is higher with robotic techniques than with other computer-assisted or manual technologies. In addition, the individual soft tissue situation of the patient is taken into account and the prosthesis position is optimized. This ensures optimum soft tissue balancing and stability of the prosthesis.

CONCLUSION

Modern robot-assisted systems are the mechanical bridge between imaging and patient. This technique provides objective control over the results produced with alternative alignments. This applies to both the prosthesis position itself and the resulting soft tissue balancing.

3D printed titanium cages combined with the Masquelet technique for the reconstruction of segmental femoral defects: Preliminary clinical results and molecular analysis of the biological activity of human-induced membranes

Introduction:

Traumatic femoral segmental bone loss is a complex clinical problem, one that often requires extreme solutions. This study examines a new treatment strategy for segmental bone loss using patient-specific 3D printed titanium cages in conjunction with the Masquelet technique.

Methods:

The study was composed of a clinical observational case series, and a basic science investigation to evaluate the biological activity of the induced membranes using histology, immunohistochemistry (IHC), and gene expression analysis. Eligible patients were: adult; post-traumatic; with segmental femoral defects; minimum follow-up 1 year; managed under a 2-stage protocol, with an interim antibiotic poly (methyl methacrylate) (PMMA) spacer. Definitive reconstruction was completed with exchange to a 3D printed custom titanium cage filled with bone graft, and stabilized with either an intramedullary (IM) nail or a lateral locked plate.

Results:

Patient-specific 3D printed titanium cages were used in 5 consecutive patients to reconstruct post-traumatic segmental femoral defects. The mean interval between stages was 100.2 days (83–119 days), the mean defect length was 14.0 cm (10.3–18.4 cm), and the mean bone defect volume measured 192.4 cc (114–292 cc). The mean length of follow-up was 21.8 months (12–33 months). There were no deep infections, fractures, nerve injuries, loss of alignment, or nonunions identified during the period of follow-up. All of the patients achieved union clinically and radiographically. Histology and IHC demonstrated a greater number of vessels, cell nuclei, and extensive staining for cluster of differentiation 68 (CD68), platelet and endothelial cell adhesion molecule 1 (PECAM-1), and vascular endothelial growth factor (VEGF) in the induced membranes compared to local fascia controls. Gene expression analysis revealed significant differential regulation of essential genes involved in inflammatory, angiogenic, and osteogenic pathways [interleukin 6 (IL-6), nuclear factor kappa B1 (NF-κB1), receptor activator of nuclear factor kappa-β ligand (RANKL), vascular endothelial growth factor A (VEGFA), angiogenin (ANG), transforming growth factor, beta 1 (TGF-β1), bone morphogenetic protein-2 (BMP-2), growth differentiation factor 5 (GDF-5), growth differentiation factor 10 (GDF-10), and runt-related transcription factor 2 (RUNX-2)] in the induced membranes.

Conclusions:

This study demonstrates that the use of a patient-specific 3D printed custom titanium cage, inserted into an induced membrane in a 2-stage protocol, can achieve very acceptable clinical outcomes in selected cases of post-traumatic femoral segmental defects. Patient-specific 3D printed titanium cages, used in conjunction with the Masquelet technique, are a promising new treatment option for managing complex trauma patients with femoral bone loss.

Level of Evidence:

Level IV (observational case series).