Vascular study of decellularized porcine long bones: Characterization of a tissue engineering model

INTRODUCTION

Massive bone allografts enable the reconstruction of critical bone defects in numerous conditions (e.g. tumoral, infection or trauma). Unfortunately, their biological integration remains insufficient and the reconstruction may suffer from several postoperative complications. Perfusion-decellularization emerges as a tissue engineering potential solution to enhance osseointegration. Therefore, an intrinsic vascular study of this novel tissue engineering tool becomes essential to understand its efficacy and applicability.

MATERIAL AND METHODS

32 porcine long bones (humeri and femurs) were used to assess the quality of their vascular network prior and after undergoing a perfusion-decellularization protocol. 12 paired bones were used to assess the vascular matrix prior (N = 6) and after our protocol (N = 6) by immunohistochemistry. Collagen IV, Von Willebrand factor and CD31 were targeted then quantified. The medullary macroscopic vascular network was evaluated with 12 bones: 6 were decellularized and the other 6 were, as control, not treated. All 12 underwent a contrast-agent injection through the nutrient artery prior an angio CT-scan acquisition. The images were processed and the length of medullary vessels filled with contrast agent were measured on angiographic cT images obtained in control and decellularized bones by 4 independent observers to evaluate the vascular network preservation. The microscopic cortical vascular network was evaluated on 8 bones: 4 control and 4 decellularized. After injection of gelatinous fluorochrome mixture (calcein green), non-decalcified fluoroscopic microscopy was performed in order to assess the perfusion quality of cortical vascular lacunae.

RESULTS

The continuity of the microscopic vascular network was assessed with Collagen IV immunohistochemistry (p-value = 0.805) while the decellularization quality was observed through CD31 and Von Willebrand factor immunohistochemistry (p-values <0.001). The macroscopic vascular network was severely impaired after perfusion-decellularization; nutrient arteries were still patent but the amount of medullary vascular channels measured was significantly higher in the control group compared to the decellularized group (p-value <0.001). On average, the observers show good agreement on these results, except in the decellularized group where more inter-observer discrepancies were observed. The microscopic vascular network was observed with green fluoroscopic signal in almost every canals and lacunae of the bone cortices, in three different bone locations (proximal metaphysis, diaphysis and distal metaphysis).

CONCLUSION

Despite the aggressiveness of the decellularization protocol on medullary vessels, total porcine long bones decellularized by perfusion retain an acellular cortical microvascular network. By injection through the intact nutrient arteries, this latter vascular network can still be used as a total bone infusion access for bone tissue engineering in order to enhance massive bone allografts prior implantation.

Female representation in orthopedic surgery: where do we stand in Belgium ?

Female underrepresentation in Orthopedic Surgery and Traumatology is a well-known issue worldwide, including in Belgium. Most of the literature comes from northern America. This two-part study aims to quantify the female workforce in orthopedic surgery in Belgium and assess the presence of unconscious biases among active orthopedic surgeons. Epidemiological data from national registries, orthopedic societies and universities in Belgium were analyzed. This included data on medical students, residents, active orthopedic surgeons and awards given by a Belgian orthopedic society. Additionally, a questionnaire was administered to Belgian orthopedic surgeons, assessing their perceptions of gender stereotypes and potential unconscious biases. 90 participants responded with 70% of men and mean age was 36 years old. The data revealed that 12% of active orthopedic surgeons in Belgium were women in 2020. However, the representation f women was higher among residents, with a thirty percent distribution. In one university, women had a slightly higher chance of getting accepted in the orthopedic training then men. The questionnaire results indicated the presence of unconscious bias regarding subspecialties, which aligned with the actual distribution. Women tend to specialize more in upper limb surgery and pediatrics while men focus more frequently on lower limb surgery. The findings highlight the need for addressing the underrepresentation of women in orthopedic surgery and traumatology in Belgium. If the current rate of progress continues, it is projected that 30% of active orthopedic surgeons will be female by the year 2074. Identifying and addressing factors contributing to the underrepresentation, such as lack of mentorship, unconscious biases, visibility issues, and discrimination, is crucial for empowering future female orthopedic surgeons and fostering diversity in the field. Collaboration among European universities and orthopedic societies can play a vital role in reducing barriers and promoting gender equality in orthopedic surgery and traumatology.

Unilateral versus simultaneous bilateral total hip arthroplasty. The Belgian experience

Bilateral hip osteoarthritis is frequent. The safety and patient selection for simultaneous bilateral total hip arthroplasty (SBTHA) are still debated. The purpose of this article is to share our experience and assess if performing SBTHA carries more risk than unilateral total hip arthroplasty (UTHA).

METHODS

A retrospective data analysis was performed on 468 patients who underwent either UTHA (418 patients) or SBTHA (50 patients) using a direct anterior approach between June 2016 and December 2020. Apart from SBTHA patients being significantly younger, there was no significant preoperative difference in demographics, comorbidities, surgical variables and biological values between the two groups. Primary outcomes were 90-days emergency room (ER) visit and readmission, as well as 90-days minor and major complications. Secondary outcomes were length of stay (LOS), operative time and blood loss.

RESULTS

90-days ER visit (p=0.244), 90- days readmission (p=0.091), overall complications rate (p=0.376), minor complications (p=0.952) and major complications (p=0.258) were not statistically different between the two groups. Operative time and average LOS were significantly longer in the SBTHA group (p<0.001). Blood loss was significantly higher (p<0.001) in the SBTHA group. However, no difference in the transfusion rate between the two groups was observed (p=0.724).

CONCLUSION

Complication rate, 90- days hospital readmission and 90-days ER visit were similar between the two groups. This study shows that performing SBTHA is a safe, effective, and doesn't carry additional risks for patients with bilateral symptomatic osteoarthritis.

Effect of splint on pain, function and quality of life in trapeziometacarpal osteoarthritis patients?

Trapeziometacarpal (TM) Osteoarthritis is one of the most common osteoarthritis. It causes pain, loss of mobility and strength and affected function in daily life. Splint is one of the conservative treatments proposed to patients. The purpose of this study was to assess the effect of this conservative treatment on pain, function and quality of life at long-term. We sent 193 questionnaires to patients who received a CMC splint for their TM osteoarthritis. The CMC splint immobilizes only the TM joint and leaves free the interphalangeal joint of the thumb and the wrist. First, we comptuted how many patients had finally undergone surgical treatment. On the non-operated patients, we analyzed the pain (VAS), the function (QuickDASH score) and the quality of life (SF-12). We compared the results to literature and norms. Finally, 186 people could be included in the study ,115 we answered and 28 were operated on (24%). After 4 years (3.8±1.7 yrs) of conservative treatment, The VAS and QuickDASH scores were significantly worse comparatively to a cohort of healthy patients, trapezectomy and arthrodesis patients. The SF-12 scores were reduced from 20% comparative to norms. In conclusion, few patients had surgery after splinting as a conservative treatment. However, these non- operated patients do not provide good results.