Modification of pore-wall in direct ink writing wollastonite scaffolds favorable for tuning biodegradation and mechanical stability and enhancing osteogenic capability.

Surface chemistry and mechanical stability determine the osteogenic capability of bone implants. The development of high-strength bioactive scaffolds for in-situ repair of large bone defects is challenging because of the lack of satisfying biomaterials. In this study, highly bioactive Ca-silicate (CSi) bioceramic scaffolds were fabricated by additive manufacturing and then modified for pore-wall reinforcement. Pure CSi scaffolds were fabricated using a direct ink writing technique, and the pore-wall was modified with 0%, 6%, or 10% Mg-doped CSi slurry (CSi, CSi-Mg6, or CSi-Mg10) through electrostatic interaction. Modified CSi@CSi-Mg6 and CSi@CSi-Mg10 scaffolds with over 60% porosity demonstrated an appreciable compressive strength beyond 20 MPa, which was ~2-fold higher than that of pure CSi scaffolds. CSi-Mg6 and CSi-Mg10 coating layers were specifically favorable for retarding bio-dissolution and mechanical decay of scaffolds in vitro. In-vivo investigation of critical-size femoral bone defects repair revealed that CSi@CSi-Mg6 and CSi@CSi-Mg10 scaffolds displayed limited biodegradation, accelerated new bone ingrowth (4-12 weeks), and elicited a suitable mechanical response. In contrast, CSi scaffolds exhibited fast biodegradation and retarded new bone regeneration after 8 weeks. Thus, tailoring of the chemical composition of pore-wall struts of CSi scaffolds is beneficial for enhancing the biomechanical properties and bone repair efficacy.

Concurrent arthroscopic meniscal repair during open-wedge high tibial osteotomy is not clinically beneficial for medial meniscus posterior root tears.

PURPOSE: This prospective study aimed to investigate the clinical benefits of meniscal repair during open-wedge high tibial osteotomies (OWHTOs) in patients with medial meniscus posterior root tears (MMPRTs) and to identify potential risk factors for meniscal healing. METHODS: Ninety patients with degenerative MMPRTs were included in the final cohort and randomized into three groups. The patients in Group A (n = 30) underwent OWHTO and arthroscopic all-inside meniscal repair concurrently, those in Group B (n = 34) underwent OWHTO only, and those in Group C (n = 26) underwent arthroscopic partial meniscectomy. Clinical and radiological outcomes were recorded, and meniscal healing was evaluated during second-look arthroscopy. Logistic regression analysis was performed to identify risk factors for meniscal healing. RESULTS: After a minimum follow-up of 24 months, no significant differences between Groups A and B regarding the final Lysholm (p = 0.689) or Hospital for Special Surgery (HSS) scores (p = 0.256) were observed. There were significant differences among the three groups regarding the hip-knee-ankle angle (HKA), weight-bearing line (WBL) ratio, medial proximal tibial angle (MPTA), and joint line convergence angle (JLCA) (p < 0.001, respectively), but the differences between Groups A and B were not significant. During second-look arthroscopy, the healing rate of the MMPRTs was significantly higher in Group A (63.3%) than in Group B (35.3%). Concurrent meniscal repair and changes in the HKA, and MPTA were risk factors for meniscal healing. CONCLUSION: Concurrent arthroscopic meniscal repair during OWHTO did not lead to significant clinical benefits in the treatment of MMPRTs, except for an increased rate of meniscal healing, which was not associated with clinical outcomes. LEVEL OF EVIDENCE: II, prospective comparative study.

New insight into biodegradable macropore filler on tuning mechanical properties and bone tissue ingrowth in sparingly dissolvable bioceramic scaffolds.

Structural parameters of the implants such as shape, size, and porosity of the pores have been extensively investigated to promote bone tissue repair, however, it is unknown how the pore interconnectivity affects the bone growth behaviors in the scaffolds. Herein we systematically evaluated the effect of biodegradable bioceramics as a secondary phase filler in the macroporous networks on the mechanical and osteogenic behaviors in sparingly dissolvable bioceramic scaffolds. The pure hardystonite (HT) scaffolds with ∼550 & 800 µm in pore sizes were prepared by digital light processing, and then the Sr-doped calcium silicate (SrCSi) bioceramic slurry without and with 30 % organic porogens were intruded into the HT scaffolds with 800 µm pore size and sintered at 1150 °C. It indicated that the organic porogens could endow spherical micropores in the SrCSi filler, and the invasion of the SrCSi component could not only significantly enhance the compressive strength and modulus of the HT-based scaffolds, but also induce osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The pure HT scaffolds showed extremely slow bio-dissolution in Tris buffer after immersion for 8 weeks (∼1 % mass decay); in contrast, the SrCSi filler would readily dissolve into the aqueous medium and produced a steady mass decay (>6 % mass loss). In vivo experiments in rabbit femoral bone defect models showed that the pure HT scaffolds showed bone tissue ingrowth but the bone growth was impeded in the SrCSi-intruded scaffolds within 4 weeks; however, the group with higher porosity of SrCSi filler showed appreciable osteogenesis after 8 weeks of implantation and the whole scaffold was uniformly covered by new bone tissues after 16 weeks. These findings provide some new insights that the pore interconnectivity is not inevitable to impede bone ingrowth with the prolongation of implantation time, and such a highly biodegradable and bioactive filler intrusion strategy may be beneficial for optimizing the performances of scaffolds in bone regenerative medicine applications.

Preoperative Leg Length Discrepancy >2 cm in the Supine Decubitus Position May Induce Compensatory Pelvic Obliquity in Patients during Total Hip Arthroplasty.

OBJECTIVES: The leg length discrepancy (LLD) in the supine decubitus position may influence the inclination angle of the acetabular component during total hip arthroplasty (THA). The relationship among LLD, pelvic obliquity, and inclination angle of the acetabular component has not been well studied. This study aimed to evaluate the relationship between LLD in supine position and changes in the inclination angle of the acetabular components during THA, and the compensatory ability of the pelvis based on LLD and inclination. METHODS: A total of 135 patients were prospectively classified into three groups according to the preoperative LLD in the supine decubitus position: the cranial type group had a positive LLD value; the fixed type group had LLD = 0; and the caudal type group had a negative LLD value. Patients in the cranial type group and caudal type group were divided into four subgroups based on the LLD value (either positive or negative): LLD >3 cm subgroup; 2 ≤ LLD ≤ 3 cm subgroup; 1 ≤ LLD < 2 cm subgroup; and LLD <1 cm subgroup. The targeted and final inclination of the acetabular component was measured intra- and postoperatively. RESULTS: The results showed a significant difference in the targeted and final inclination angles among the patients in the cranial type and the caudal type groups. In the caudal type group, increased inclination was observed in the patients of LLD >3 cm subgroup (mean 3.13°) and 2 ≤ LLD ≤ 3 cm subgroup (mean 5.17°) after THA, respectively. Decreased inclination (mean, 6.16°) was observed in 2 ≤ LLD ≤ 3 cm subgroup in the cranial type group after THA. CONCLUSIONS: Our findings revealed that in patients with discrepancy greater than 2 cm, postural pelvic obliquity imposed a remarkable influence on the inclination.

Application of 3D-bioprinted nanocellulose and cellulose derivative-based bio-inks in bone and cartilage tissue engineering.

212Three-dimensional (3D) printing is a modern, computer-aided, design-based technology that allows the layer-by-layer deposition of 3D structures. Bioprinting, a 3D printing technology, has attracted increasing attention because of its capacity to produce scaffolds for living cells with extreme precision. Along with the rapid development of 3D bioprinting technology, the innovation of bio-inks, which is recognized as the most challenging aspect of this technology, has demonstrated tremendous promise for tissue engineering and regenerative medicine. Cellulose is the most abundant polymer in nature. Various forms of cellulose, nanocellulose, and cellulose derivatives, including cellulose ethers and cellulose esters, are common bioprintable materials used to develop bio-inks in recent years, owing to their biocompatibility, biodegradability, low cost, and printability. Although various cellulose-based bio-inks have been investigated, the potential applications of nanocellulose and cellulose derivative-based bio-inks have not been fully explored. This review focuses on the physicochemical properties of nanocellulose and cellulose derivatives as well as the recent advances in bio-ink design for 3D bioprinting of bone and cartilage. In addition, the current advantages and disadvantages of these bio-inks and their prospects in 3D printing-based tissue engineering are comprehensively discussed. We hope to offer helpful information for the logical design of innovative cellulose-based materials for use in this sector in the future.

Comparison of osteogenic capability of 3D-printed bioceramic scaffolds and granules with different porosities for clinical translation.

Pore parameters, structural stability, and filler morphology of artificial implants are key factors influencing the process of bone tissue repair. However, the extent to which each of these factors contributes to bone formation in the preparation of porous bioceramics is currently unclear, with the two often being coupled. Herein, we prepared magnesium-doped wollastonite (Mg-CSi) scaffolds with 57% and 70% porosity (57-S and 70-S) via a 3D printing technique. Meanwhile, the bioceramic granules (57-G and 70-G) with curved pore topography (IWP) were prepared by physically disrupting the 57-S and 70-S scaffolds, respectively, and compared for in vivo osteogenesis at 4, 10, and 16 weeks. The pore parameters and the mechanical and biodegradable properties of different porous bioceramics were characterized systematically. The four groups of porous scaffolds and granules were then implanted into a rabbit femoral defect model to evaluate the osteogenic behavior in vivo. 2D/3D reconstruction and histological analysis showed that significant bone tissue production was visible in the central zone of porous granule groups at the early stage but bone tissue ingrowth was slower in the porous scaffold groups. The bone tissue regeneration and reconstruction capacity were stronger after 10 weeks, and the porous architecture of the 57-S scaffold was maintained stably at 16 weeks. These experimental results demonstrated that the structure-collapsed porous bioceramic is favorable for early-stage osteoconduction and that the 3D topological scaffolds may provide more structural stability for bone tissue growth for a long-term stage. These findings provide new ideas for the selection of different types of porous bioceramics for clinical bone repair.

Fully arthroscopic treatment of medial Hoffa fracture associated with anterior cruciate ligament tear: case report and surgical technique.

A Hoffa fracture is a rare intra-articular injury consisting of a coronal plane fracture of one or both of the distal femoral condyles. Because of the rarity of medial Hoffa fractures, only a few reports have described this injury and its arthroscopic management. In this article, we present a rare case involving a 32-year-old man with a displaced medial Hoffa fracture associated with a proximal anterior cruciate ligament tear. He was treated by a single-stage fully all-inside arthroscopic technique. Arthroscopic-assisted internal fixation ensured fragment stability and enabled us to visualize the fracture reduction, monitor the screw insertion, and reconstruct the anterior cruciate ligament tear at the same time. This technique is a novel but demanding treatment method for medial Hoffa fractures and is particularly useful for properly selected patients with associated intra-articular knee injuries.

Risk factors for iliopsoas impingement after total hip arthroplasty using a collared femoral prosthesis.

BACKGROUND: The relationship between collar design of a femoral component and iliopsoas impingement (IPI) after total hip arthroplasty (THA) is still underrecognized. The purpose of our study was to determine the possible risk factors for IPI related to the femoral component, when using a collared femoral prosthesis. METHODS: A total of 196 consecutive THA patients (206 hips) using a collared femoral prosthesis were reviewed retrospectively after exclusion of the factors related to acetabular component and femoral head. The patients were divided into +IPI and -IPI group according to the presence of IPI. Radiological evaluations were performed including femoral morphology, stem positioning, and collar protrusion length (CPL). Multivariate regression analysis was performed to assess the risk factors for IPI. RESULTS: At a minimum follow-up of 1 year, IPI was observed in 15 hips (7.3%). Dorr type C proximal femur was found in nine hips (60%) in the +IPI group and in 28 hips in the -IPI group (14.7%, p < 0.001). The mean stem anteversion in the +IPI group was significantly greater than that in the -IPI group (19.1° vs. 15.2°, p < 0.001), as well as the mean CPL (2.6 mm vs. - 0.5 mm, p < 0.001). The increased stem anteversion (OR = 1.745, p = 0.001) and CPL (OR = 13.889, p = 0.001) were potential risk factors for IPI. CONCLUSIONS: The incidence of IPI after THA is higher than expected when using a collared femoral prosthesis. Among the factors related to collared femoral prosthesis, excessively increased stem anteversion and prominent collar protrusion are independent predictors for IPI. In addition, high risk of IPI should be carefully considered in Dorr type C bone, despite that femoral morphology is not a predictive factor. LEVEL OF EVIDENCE: Level IV, clinical cohort study.

Composition control in biphasic silicate microspheres on stimulating new bone regeneration and repair of osteoporotic femoral bone defect.

Application of bioactive materials as synthetic bone graft substitutes in regenerative medicine has seen great evolution over the past decades in treating challengeable bone defects. However, balancing the preparation conditions and biological performances of inorganic biomaterials remain a great challenge, especially when there is lack of biomaterial design on how to control component distribution and how pathological bone responds to the biomaterial stimulations and osteogenesis. Here, our objective is to develop yolk-shell Ca-silicate microspheres and to investigate the potential biological performances to overcome the limitations in repair of osteoporotic bone defects. The introduction of ß-calcium silicate (CaSiO3 ) or mesoporous bioactive glass (MBG) into self-curing ß-dicalcium silicate (Ca2 SiO4 ) cement shell to form spherical granules (CaSiO3 @Ca2 SiO4 , MBG@Ca2 SiO4 ) was to retain the physicochemical property and/or microstructure of each component for optimizing bioactive ion release that could maximize osteostimulation in osteoporosis. We report a scalable shape-controlled mild fabrication protocol to yield the yolk-shell granules, endowing to different phases in yolk layer and interconnected macropore networks in the closely packed granule scaffolds. This unique heterostructure preparation is governed by coaxially aligned bilayer nozzle, inorganic powders and biocompatible binders. Extensive in vitro and in vivo evaluation showed that the CaSiO3 @Ca2 SiO4 and MBG@Ca2 SiO4 granules exhibited many superior properties such as controllable ion release, improved biodegradation and enhanced osteogenic capability in comparison with the pure Ca2 SiO4 @Ca2 SiO4 , thereby opening new mild-condition approach in fabricating osteogenesis-tailored silicate biomaterials for bone regenerative medicine, especially for efficient reconstruction of challenging pathological bone defects.

Effect of topical tranexamic acid in total hip arthroplasty patients who receive continuous aspirin for prevention of cardiovascular or cerebrovascular events: A prospective randomized study.

BACKGROUND: Due to differences in pharmacological mechanism of action, the effect of tranexamic acid (TA) on aspirin-related bleeding remains unknown. We therefore conducted a prospective randomized study to elucidate: (1) the effect of topical TA administration on blood loss and transfusion rate in total hip arthroplasty (THA) patients receiving continuous aspirin for prevention of cardiovascular or cerebrovascular events; (2) 90-day complications of topical TA administration; (3) possible variables contributing to blood transfusion. HYPOTHESIS: Topical TA administration reduces blood loss and transfusion rate in THA patients receiving continuous aspirin. PATIENTS AND METHODS: A total of 102 consecutive THA patients taking continuous aspirin were enrolled and randomized into two groups. In the topical TA (TTA) group (n=55), topical TA was administered at three points during THA; in the control group (n=47), the patients received saline solution as placebo. Based on drop in hemoglobin concentration, total estimated blood loss was calculated as the main assessment criterion. Secondary assessment criteria included transfusion rate and 90-day complications. Finally, a multivariate regression model was used to assess possible predictive factors for blood transfusion. RESULTS: (1) Significantly lower total blood loss was observed in the TTA group than in the control group (897±177ml vs. 1153±345ml, p<0.001). Furthermore, lower transfusion rate was observed in the TTA group than in the control group (10.9% vs. 34.0%, p=0.005). (2) No significant difference was observed between the two groups regarding 90-day complications. (3) We identified higher preoperative hemoglobin level (OR=0.675, p=0.002) and topical TA administration (OR=0.002, p=0.012) as negative predictive factors for blood transfusion. DISCUSSION: Topical application of TA was safe and beneficial in THA patients receiving continuous aspirin for prevention of cardiovascular or cerebrovascular events, to reduce blood loss and transfusion rate, without increasing the risk of 90-day complications.

Core-Shell Biphasic Microspheres with Tunable Density of Shell Micropores Providing Tailorable Bone Regeneration.

IMPACT STATEMENT: We have developed the new core-shell bioceramic CSi-Sr4@CaP-px microspheres with tuning porous shell layer so that the biodegradation of both CSi-Sr4 core and CaP shell is readily adjusted synergistically. This is for the first time, to the best of our knowledge, that the bioceramic scaffolds concerning gradient distribution and microstructure-tailoring design is available for tailoring biodegradation and ion release (bioactivity) to optimizing osteogenesis. Furthermore, it is possibly helpful to develop new bioactive scaffold system for time-dependent tailoring bioactivity and microporous structure to significantly enhance bone regeneration and repair applications, especially in some non-load-bearing arbitrary 3D anatomical bone and teeth defects.