Bone Defects in Tibia Managed by the Bifocal Versus Trifocal Bone Transport Technique

Background: The purpose of this study was to evaluate the clinical effectiveness and determine the differences, if any, between trifocal and bifocal bone transport technique in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator. Methods: A total of 53 consecutive patients with long segmental tibial bone defects caused by infection and treated by monolateral rail external fixator in our department were retrospectively collected and analyzed from January 2013 to April 2019, including 39 males and 14 females with an average age of 38.8±12.4 years (range 19 to 65 years). 32 patients were treated by bifocal bone transport (BFT) technique, and the other 21 patients were managed by trifocal bone transport (TFT) technique. The demographic data, operation duration, docking time, external fixation time, and external fixation index were documented and analyzed. Difficulties that occur during the treatment were classified according to Paley. The clinical outcomes were evaluated by the Association for the Study and Application of the Method of Ilizarov criteria (ASAMI) at the last clinical visit.Results: All patients achieved an infection-free union finally, and there was no significant difference between the two groups in demographic data and both ASAMI bone and functional scores (P>0.05). The mean defect size and operation duration in TFT (9.4±1.5 cm, 161.9±8.9 minutes) were larger than that in BFT (7.8±1.8 cm, 122.5±11.2 minutes) (P<0.05). The mean docking time, external fixation time, and external fixation index in TFT (65.9±10.8 days, 328.0±57.2 days, 34.8±2.1 days/cm) were all less than those in BFT (96.8±22.6 days, 474.5±103.2 days, 60.8±1.9 days/cm) (P<0.05). Difficulties and complications were more prevalent in the BFT group, while less in the TFT group (P<0.05). Conclusions: Both the trifocal and bifocal bone transport technique in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator achieve satisfactory clinical outcomes. The trifocal bone transport technique can significantly decrease the docking time, external fixation time, external fixation index, difficulties, and complications compared with the bifocal bone transport technique.

Design of Porous Metal Block Augmentation to Treat Tibial Bone Defects in Total Knee Arthroplasty Based on Topology Optimization

Metal block augmentation, which is used for the treatment of tibial bone defects in total knee arthroplasty, with high stiffness will cause significant alteration in stress distribution, and its solid structure is not suitable for osseointegration. This study aimed to design a porous block to reduce weight, promote bone ingrowth, and improve its biomechanical performance. The metal block augmentation technique was applied to finite element models of tibial bone defects. Minimum compliance topology optimization subject to volume fraction combined with the porous architecture was adopted to redesign the block. Biomechanical changes compared with the original block were analyzed by finite element analysis. The stress distribution of the block and proximal tibia was recorded. The strain energy density of the proximal tibia was obtained. The newly designed block realized 40% weight reduction. The maximum stress in the optimized block decreased by 11.6% when compared with the solid one. The maximum stress of the proximal tibia in the optimized group increased by 18.6%. The stress of the anterior, medial, and posterior parts of the proximal medial tibia in the optimized group was significantly greater than that in the original group (all p &lt; 0.05). The optimized block could effectively improve the biomechanical performance between the block and the bone. The presented method might provide a reference for the design of customized three-dimensional printed prostheses.

COMBINED USE OF HYALURONIC ACID WITH NANO-BIOACTIVE GLASS ENHANCED BIOCEMENT BASED SILICATE STIMULATED BONE REGENERATIVE CAPACITY IN TIBIAL BONE DEFECTS OF RABBITS: IN-VIVO STUDY

An ideal biomaterial for bone regeneration is a longstanding quest nowadays. This study aimed to evaluate the osteogenic potentiality of nano-bioactive glass enhanced biocement based silicate with or without hyaluronic acid seeded in rabbits’ tibial bone defects. For this, 24 male rabbits with two 5 mm defects (1 defect per tibia) were divided into three equal groups. Among the predefined three groups, for the rabbits of group 1(control) bone defects were left untreated while for the members of group 2 defects received nano-bioactive glass enhanced biocement based silicate cement, and group 3 defects received nano-bioactive glass cement mixed with hyaluronic acid. Animals of each group were divided equally for euthanization after 3 and 6 weeks. Bone specimens were processed and examined histologically with histomorphometrically analysis of new bone area percentage. The bone defects in group 3 showed significantly improved osseous healing histologically as compared to the group 1&2. The morphometric analysis also revealed a significant increase in the new bone area percentage in group 3 as compared to the group 1 and 2 (P < 0.05). The results of the present study can be concluded that bone defects could be treated with nano-bioactive glass and hyaluronic acid cement. Although, nano-bioactive glass alone was capable of bone regeneration the combination of both had significant regenerative capacity.