Hybrid closing-wedge DTO using PSI was selected for a patient wit severe deformity post-fracture malunion, which enable good alignment correction and patient satisfaction.

BACKGROUND: High tibial osteotomy (HTO) is an effective treatment option for deformity correction after fracture. However, performing precise corrective osteotomy for cases with a severe varus deformity and a significant posterior slope poses a significant challenge. Three-dimensional (3D) bone model construction and patient-specific instrumentation (PSI) created from preoperative Computed tomography (CT) may be useful tools in achieving successful outcome for such cases. The present technique describes a hybrid closing-wedge distal tuberosity tibial osteotomy (Hybrid CWDTO) using two PSIs. METHODS: Preoperative planning was performed in 3D with reference to the contralateral normal lower extremity CT taken preoperatively, which was then mirrored for analysis. A full-scale bone model and two PSIs were constructed based on this plan to allow for complex correction. During surgery, osteotomy was performed using these sterilized PSIs as guides. RESULTS: Radiographic imaging showed that medial proximal tibial angle (MPTA) improved from 68 to 84 degrees and posterior tibial slope (PTS) improved from 19 to 6 degrees. The standing leg radiograph showed a mechanical varus alignment improvement from 12 to 3 degrees. The 2011 Knee Society Scoring system (2011 KSS) improved from 31 to 95 in objective knee indicators, from 10 to 24 in symptoms, from 14 to 40 in patient satisfaction and from 51 to 95 in activities. CONCLUSION: Hybrid CWDTO using PSIs is a useful surgical technique for alignment correction post-malunion while also achieving high patient satisfaction. This can assist surgeons in treating complex deformities that are otherwise difficult to treat.

Plastic deformation of synthetic quartz nanopillars by nanoindentation for multi-scale and multi-level security artefact metrics.

Individual authentication using artefact metrics has received increasing attention, as greater importance has been placed on the security of individual information. These artefact metrics must satisfy the requirements of individuality, measurement stability, durability, and clone resistance, in addition to possessing unique physical features. In this study, we proposed that nanostructures of synthetic quartz (SQ) deposited on an SQ plate may provide sophisticated artefact metrics if morphological changes could be intentionally introduced into the SQ nanostructures at certain positions. We fabricated SQ nanopillars using a mass-production method (ultraviolet nanoimprint lithography) and investigated their mechanical deformation using nanoindentation with a spheroid diamond tip through a loading and unloading cycle. The SQ nanopillars with an aspect ratio of 1 (i.e., diameters D of 100 and 200 nm with corresponding heights H of 100 and 200 nm, respectively) could be plastically deformed without collapsing within a specified pillar-array format at programmed positions. The plastically deformed SQ nanopillar arrays demonstrated multi-scale (sub-millimetre, micrometre, and nanometre) and multi-level (shape, area, diameter, and height) individuality authentication and clone resistance. Because SQ is physically and chemically stable and durable, individuality authentication can be a highly reliable tool on Earth and in space.

Enhancement of tendon-bone interface healing and graft maturation with cylindrical titanium-web (TW) in a miniature swine anterior cruciate ligament reconstruction model: histological and collagen-based analysis.

BACKGROUND: Tendon-bone interface healing and ligamentization of the graft in anterior cruciate ligament (ACL) reconstruction with autografts are important factors affecting treatment outcome. This study aimed to investigate the effectiveness of a cylindrical titanium-web (TW) in tendon-bone interface healing and graft maturation in ACL reconstruction. METHODS: Fourteen mature female CLAWN miniature swine underwent bilateral ACL reconstructions with patellar tendon (PT) autografts. In one limb, the TW/tendon complex was placed into the proximal side of the tibial tunnel. Only the graft was transplanted into the tunnel in the control limb. The proximal side of the graft was sutured into the stump of the native ACL and the distal end was stapled to the tibia. The animals were euthanized at 4 and 15 weeks postoperatively, for histological and biochemical analyses. RESULTS: Microscopic images in TW limbs showed that ingrowth of tendon-like tissue and mineralized bone tissue into the TW connected the bone and the tendon directly. In contrast, fibrous tissue intervened between the bone and tendon in the control limbs. The total amount of collagen cross-links (which defines the strength of collagen fibers) and the maturation of collagen cross-links in TW tendons were significantly higher (p < 0.05) than those of control limbs. There was no significant difference in the ratio of dihydroxy-lysinonorleucine to hydroxy-lysinonorleucine (an indicator of tissue specific collagen maturation) between TW tendons and that of the native PT. CONCLUSIONS: TW promoted the maturation and formation of collagen cross-links in the grafted tendon while maintaining the cross-links pattern of native tendon collagen, and enabled direct binding of tendon to bone.

Accuracy of Computed Tomography-Based Navigation-Assisted Total Knee Arthroplasty: Outlier Analysis.

BACKGROUND: Achieving neutral limb alignment during total knee arthroplasty (TKA) has been identified as a potential factor in long-term prosthesis survival. This study aimed to analyze the accuracy of component orientation and postoperative alignment of the leg after computed tomography (CT)-based navigation-assisted TKA, compare these parameters with those of a conventional technique, and analyze differences in the data of outliers. METHODS: We retrospectively compared the alignment of 130 TKAs performed with a CT-based navigation system with that of 67 arthroplasties done with a conventional system. The knee joints were evaluated using radiographs. RESULTS: Mean hip-knee-ankle (HKA) angle, frontal femoral component angle, and frontal tibial component angle were 180.7°, 88.8°, and 90.6°, respectively, for the navigation-assisted arthroplasties and 181.1°, 88.7°, and 90.2°, respectively, for the conventional arthroplasties. All preoperative leg axes of 10 outliers in the navigation group were >193°, whereas the data of 17 outliers in the conventional group were scattered. CONCLUSION: This study demonstrates significant improvements in component positioning with the CT-based navigation system. Furthermore, when analyzing cases with preoperative HKA angles ≤192°, no outliers were found in the navigation group, indicating high alignment accuracy. However, in cases with preoperative HKA angles ≥193°, outliers were found in both groups, and no significant difference between the groups was observed (P = .08). Detailed analysis of the outlier cases in the navigation group revealed that the femoral component was placed in the varus position. These findings indicate that the varus knee is an important factor influencing accurate positioning of the femoral component and the postoperative leg axis.