Kirigami-based metastructures with programmable multistability.

SignificanceDifferent from most existing multistable structures whose multiple stable states are achieved through the combinational effect of bistable units, we invent a generic tristable kirigami cuboid. The three stable states have fundamentally distinct geometric configurations and chirality, and the transformation among them can be realized by tension/compression or clockwise/counterclockwise twist. Tessellating the units in series, a family of multistable metamaterials can be constructed, the mechanical behaviors of which are programmable by the unit geometry, the material of the elastic joints, the number of units, and the loading conditions. As a demonstration of the potential applications, a frequency reconfigurable antenna for 5G triple-band communication is developed based on a tristable unit, and the frequency tunability is verified by experiments.

Deep Learning and Geometry Flow Vector Using Estimating Vehicle Cuboid Technology in a Monovision Environment.

This study introduces a novel model for accurately estimating the cuboid of a road vehicle using a monovision sensor and road geometry information. By leveraging object detection models and core vectors, the proposed model overcomes the limitations of multi-sensor setups and provides a cost-effective solution. The model demonstrates promising results in accurately estimating cuboids by utilizing the magnitudes of core vectors and considering the average ratio of distances. This research contributes to the field of intelligent transportation by offering a practical and efficient approach to 3D bounding box estimation using monovision sensors. We validated feasibility and applicability are through real-world road images captured by CCTV cameras.

Anatomic Description of the Calcaneocuboid Joint: Implications for Staple Fixation.

Understanding the anatomy of the calcaneocuboid (CCJ) remains essential when selecting staple fixation to optimize osseous purchase during rearfoot procedures. This anatomic study quantitatively describes the CCJ in relation to staple fixation sites. The calcaneus and cuboid from 10 cadavers were dissected. Widths at 5 mm and 10 mm increments away from the joint were measured in dorsal, midline, and plantar thirds of each bone. The widths between each position's 5 mm and 10 mm increments were compared using the Student's t test. The widths among the positions at both distances were compared using an ANOVA then post hoc testing. Statistical significance was set at p ≤ 0.05. The middle (23 ± 3 mm) and plantar third (18 ± 3 mm) of the calcaneus at the 10 mm interval was greater than the 5 mm interval (p = .04). At 5 mm distal to the CCJ, the dorsal third of the cuboid maintained a statistically significant greater width than the plantar third (p = .02). The 5 mm (p = .001) and 10 mm (p = .005) dorsal calcaneus widths as well as the 5 mm (p = .003) and 10 mm (p = .007) middle calcaneus widths were significantly greater than the plantar widths. This investigation supports the use of 20 mm staple 10 mm away from the CCJ in dorsal and midline orientations. Care should be taken when placing a plantar staple within 10 mm proximal to the CCJ as the legs may extend beyond the medial cortex compared to dorsal and midline placements.

Anatomical basis of a pedicled cuboid bone graft based on the lateral tarsal artery for talar avascular necrosis.

PURPOSE: Vascularized pedicled bone-grafting from the cuboid to the talus provides low donor site morbidity and satisfactory outcomes in patients with early-stage talar avascular necrosis. We investigated the anatomy of the rotational vascularized pedicled bone graft from the cuboid. METHODS: 15 embalmed cadaver specimens were perfused with red latex via the popliteal artery. The lateral malleolus was dissected. The course of the lateral tarsal artery and the vascular territory in the cuboid supplied by the lateral tarsal artery were observed. Vessel diameters were measured. RESULTS: The course of the lateral tarsal artery to the cuboid was consistent, and a vascularized pedicle of the lateral tarsal artery was present in all specimens. Mean diameter of the lateral tarsal artery was 1.40 ± 0.12 mm (range 1.67-1.25). Mean length of the vascularized pedicle was 67.15 ± 3.18 mm (range 62.43-74.36). The pedicle bone graft was long enough to reach the bony border of both the lateral and medial malleolus. CONCLUSION: A vascularized pedicled cuboid bone graft based on the lateral tarsal artery has clinical utility for early-stage talar avascular necrosis.

A Cuboid Spider Silk: Structure-Function Relationship and Polypeptide Signature.

A unique cuboid spider silk from the outer egg sac of Nephila pilipes, with an unusual square cross-section, is disclosed. The structure-function relationships within this silk are first studied through structural characterization, mechanical measurement, protein conformation, and polypeptide signature of silk proteins. This silk maintains the higher stiffness property of egg sac silks, and also shows a species difference. Environmental response of the mechanical properties within this silk are observed. Synchrotron FTIR microspectroscopy is used to monitor the silk protein conformation in a single natural silk. The ß-sheet structure aligns parallel to the fiber axis with a content of 22% ± 2.6%. The de novo resulting polypeptide from the solid silk fibers are novel, and an abundant polar amino acid insertion is observed. Short polyalanine (An , n ≤ 3), alternating serine and alanine (S/A)X, and alternating glycine and alanine (G/A)X, GGX, and SSX dominates in the resulting de novo polypeptide. This accords with the composition pattern of other egg sac silk proteins, besides the rarely observed GGX. This study broadens the library of egg sac spider silks and provides a new perspective to uncover structure-function relationships in spider silk.

The peroneus longus muscle and tendon: a review of its anatomy and pathology.

This article will review the anatomy and common pathologies affecting the peroneus longus muscle and tendon. The anatomy of the peroneus longus is complex and its long course can result in symptomatology referable to the lower leg, ankle, hindfoot, and plantar foot. Proximally, the peroneus longus muscle lies within the lateral compartment of the lower leg with its distal myotendinous junction arising just above the level of the ankle. The distal peroneus longus tendon has a long course and makes two sharp turns at the lateral ankle and hindfoot before inserting at the medial plantar foot. A spectrum of pathology can occur in these regions. At the lower leg, peroneus longus muscle injuries (e.g., denervation) along with retromalleolar tendon instability/subluxation will be discussed. More distally, along the lateral calcaneus and cuboid tunnel, peroneus longus tendinosis and tears, tenosynovitis, and painful os peroneum syndrome (POPS) will be covered. Pathology of the peroneus longus will be illustrated using clinical case examples along its entire length; these will help the radiologist understand and interpret common peroneus longus disorders.

Incremental 3D Cuboid Modeling with Drift Compensation.

This paper presents a framework of incremental 3D cuboid modeling by using the mapping results of an RGB-D camera based simultaneous localization and mapping (SLAM) system. This framework is useful in accurately creating cuboid CAD models from a point cloud in an online manner. While performing the RGB-D SLAM, planes are incrementally reconstructed from a point cloud in each frame to create a plane map. Then, cuboids are detected in the plane map by analyzing the positional relationships between the planes, such as orthogonality, convexity, and proximity. Finally, the position, pose, and size of a cuboid are determined by computing the intersection of three perpendicular planes. To suppress the false detection of the cuboids, the cuboid shapes are incrementally updated with sequential measurements to check the uncertainty of the cuboids. In addition, the drift error of the SLAM is compensated by the registration of the cuboids. As an application of our framework, an augmented reality-based interactive cuboid modeling system was developed. In the evaluation at cluttered environments, the precision and recall of the cuboid detection were investigated, compared with a batch-based cuboid detection method, so that the advantages of our proposed method were clarified.

Complete Cuboid Dislocation With Associated Lisfranc Injury: A Case Report and Review of the Literature.

Cuboid dislocations are rare midfoot injuries that usually occur in the setting of high-energy trauma. Diagnosis can be challenging and optimal treatment remains unknown. This case report and review aims to summarize the recent literature on this topic.

MRI of Cuboid Pulley Lesion.

OBJECTIVE: The aim of this study was to describe cuboid pulley lesions and associated abnormalities on the basis of clinical findings and the results of MRI examinations of the ankle. MATERIALS AND METHODS: A retrospective search was performed to identify patients who had a cuboid pulley lesion during a 10-year period. A cuboid pulley lesion was defined as bone marrow edema in the lateroplantar ridge of the cuboid that was shown to be wrapped by the peroneus longus tendon on MRI of the ankle. A total of 19 patients (11 men and eight women; mean age, 45.4 years) were included in the group of patients with a cuboid pulley lesion, and 38 age-and sex-matched patients without a cuboid pulley lesion were randomly selected as the control group. We reviewed medical records and assessed MRI findings that could be associated with a cuboid pulley lesion. RESULTS: The mean (± SD) diameter of the cuboid pulley lesion was 8.9 ± 4.7 mm. Cuboid pulley lesions were associated with peroneal tenosynovitis (p < 0.001), Achilles enthesitis (p = 0.004), and a clinical diagnosis of inflammatory arthritis (p < 0.001). Eleven of the 19 patients in the group with cuboid pulley lesions had inflammatory arthritis (either rheumatoid arthritis [n = 7] or spondyloarthritis [n = 4]). The cuboid pulley lesions did not cause localized lateral foot pain and tenderness, except in one patient who had an accompanying stress fracture of the cuboid. CONCLUSION: MRI of the ankle rarely but clearly shows cuboid pulley lesions, which themselves are not likely to cause localized pain, and cuboid pulley lesions show significant associations with peroneal tenosynovitis, Achilles enthesitis, and clinically diagnosed inflammatory arthritis.

MR imaging features of cuboid fractures in children.

BACKGROUND: Cuboid fractures are rare, usually occult on initial radiographs and are often underdiagnosed. MRI is more sensitive than radiographs for detecting acute, non-displaced cuboid fractures in adults, but only case reports have described these findings in children. OBJECTIVE: To summarize the MR and clinical features of cuboid fractures and compare MR findings with initial and follow-up radiographs in a cohort of children. MATERIALS AND METHODS: A retrospective search for patients <18 years of age with cuboid fractures was performed during a 10-year period at a large tertiary children's hospital. Subjects with cuboid fractures reported on MRI and available clinical history were included. MR images were evaluated for fracture location, fracture morphology, percentage of marrow edema in the cuboid, subchondral disruption, and associated tendon or ligamentous injury. Initial and short-term follow-up radiographs were also reviewed when available. RESULTS: Nineteen children ages 18 months to 17 years (mean: 9.0 years, standard deviation: 4.1 years, 63% boys) were diagnosed with cuboid fractures by MRI. Most cases of cuboid fractures are related to acute trauma (63%) but can be seen as stress fractures (16%). Most fractures (17/19, 89%) were linear in configuration. Fractures were most commonly adjacent to the tarsometatarsal joint (10/19, 52%). The degree of marrow edema was variable. Ligamentous injury was seen in two patients and tendon pathology was seen in one, all adolescents. Initial radiographs (n=10) were negative in 9 cases (90%). All available follow-up radiographs (n=12, obtained 19-42 days after MRI) demonstrated sclerosis in the region of the fracture. CONCLUSION: MR-depicted cuboid fractures in children typically occur in isolation. The fractures were most commonly adjacent to the tarsometatarsal joint and linear in morphology. Initial radiographs were usually normal and follow-up radiographs depicted sclerosis at the site of fracture in all available cases.

The location of the peroneus longus tendon in the cuboid groove: sonographic study in various positions of the ankle-foot in asymptomatic volunteers.

OBJECTIVE: To evaluate the normal location of the peroneus longus tendon (PL) in the cuboid groove in various ankle-foot positions by ultrasonography in asymptomatic volunteers. MATERIALS AND METHODS: Ultrasonographic assessment of the PL in the cuboid groove was performed in 20 feet of ten healthy volunteers. Each PL was examined in five ankle-foot positions (i.e., neutral, dorsiflexion, plantar-flexion, supination, and pronation). The PL location was qualitatively categorized as "inside" when the PL was entirely within the cuboid groove, as "overlying" when some part of the PL was perched on the cuboid tuberosity, and as "outside" when the PL was entirely on the cuboid tuberosity. For quantitative evaluation of the PL location, the distance between the PL and the cuboid groove was measured. The width of the cuboid groove was measured in the neutral position. RESULTS: The PL location did not significantly change with changes in the ankle-foot position. Qualitatively, an "overlying" PL was the most common type, regardless of the ankle-foot position. "Inside" PLs were found in only 35, 20, 30, 25, and 35% of feet in neutral, dorsiflexion, plantar-flexion, supination, and pronation positions, respectively. The quantitative PL location was also not significantly different among all ankle-foot positions and it was significantly negatively correlated with the cuboid groove width. CONCLUSIONS: In healthy volunteers, 65% or more of the PLs were partially or completely located outside of the cuboid groove, regardless of the ankle-foot position. The PL location relative to the cuboid groove was related to the cuboid groove width.

Spontaneous Fracture of the Os Peroneum With Rupture of the Peroneus Longus Tendon.

Rupture of the peroneus longus tendon with or without an associated os peroneum fracture is rare and uncommonly encountered in the published data. Owing to the infrequent nature, a high index of suspicion is required. Otherwise, the opportunity for the injury to result in a delayed or missed diagnosis is increased. We report the case of a 39-year-old male with spontaneous rupture of the peroneus longus tendon and associated fracture of the os peroneum. The spontaneous rupture and fracture were diagnosed from the history, physical examination, and imaging findings. The patient elected to undergo operative repair, with excellent results, full recovery, and full return to normal function.

Stabilization of the Fourth Metatarsal-Cuboid Lateral Lisfranc Injury: Early Results of an Innovative Technique Using Suture Anchors.

This report presents an innovative surgical technique for the correction of cuboid-metatarsal subluxation at the level of the lateral Lisfranc joint. This stabilization technique reinforces the dorsal fourth tarsometatarsal ligament by incorporating sutures and anchors, establishing a more stable joint. The data from 5 female patients undergoing stabilization using a suture anchor construct were reviewed. All 5 patients were able to resume their activities, including the adolescent athletes. Anatomic reconstruction of the dorsal fourth tarsometatarsal ligament complex can lead to full mechanical and functional stability, which ultimately allows for a return to activity, even in highly demanding sports and athletes.

Osteochondroma of the Cuboid: A Case Report.

Osteochondromas are common benign exostoses with <1% of pedal occurrences. Several cases of osteochondromas have been previously reported in the foot and ankle but none from the cuboid. In the present study, we report a case of osteochondroma originating from the cuboid in a 29-year-old male patient. The patient presented with an aching and shooting pain to his left foot that had progressed during the course of 3 years. Originally diagnosed as a fibroma, the patient had undergone cortisone injections that did not help with his symptoms. Radiographic and magnetic resonance imaging revealed an osteochondroma to the patient's left cuboid. Surgical removal of the tumor confirmed the diagnosis. The patient had an uneventful postoperative recovery and had no recurrence after 1.5 years of follow-up. In conclusion, although osteochondromas are rare in the foot and ankle and most are benign, they can result in many symptoms and can impair patients' quality of life, such as occurred in our patient. Recommendations for surgical excision should be determined on a case-by-case basis.

Vesicle Origami: Cuboid Phospholipid Vesicles Formed by Template-Free Self-Assembly.

Phospholipid liposomes are archetypical self-assembled structures. To minimize the surface tension, the vesicles typically are spherical. Deciphering the bilayer code, the basic physical interactions between phospholipids would allow these molecules to be utilized as building blocks for novel, non-spherical structures. A 1,2-diamidophospholipid is presented that self-assembles into a cuboid structure. Owing to intermolecular hydrogen bonding, the bilayer membranes form an exceptionally tight subgel packing, leading to a maximization of flat structural elements and a minimization of any edges. These conditions are optimized in the geometrical structure of a cube. Surprisingly, the lateral surface pressure in the membrane is only one third of the value typically assumed for a bilayer membrane, questioning a long-standing rule-of-thumb.

Plantar talar head contusions and osteochondral fractures: associated findings on ankle MRI and proposed mechanism of injury.

OBJECTIVE: To evaluate the significance of plantar talar head injury (PTHI) in predicting osseous and soft tissue injuries on ankle MRI. MATERIALS AND METHODS: The IRB approved this HIPAA-compliant retrospective study. The study group consisted of 41 ankle MRIs with PTHI that occurred at our institution over a 5 ½ year period. Eighty MRIs with bone injuries in other locations matched for age, time interval since injury, and gender formed a control group. Injuries to the following structures were recorded: medial malleolus, lateral malleolus/distal fibula, posterior malleolus, talus, calcaneus, navicular, cuboid, lateral, medial and syndesmotic ligaments, spring ligament complex, and extensor digitorum brevis (EDB) muscle. Twenty separate logistic regressions determined which injuries PTHI predicted, using the Holm procedure to control for family-wise alpha at 0.05. RESULTS: PTHI strongly predicted the occurrence of injuries involving the anterior process of the calcaneus [24 % of cases, odds ratio (OR) 12.66], plantar components of the spring ligament (27 %, OR 9.43), calcaneal origin of the EDB and attachment of the dorsolateral calcaneocuboid ligament (22 %, OR 7.22), cuboid (51 %, OR 6.58), EDB (27 %, OR 5.49), anteromedial talus (66 %, OR 4.78), and posteromedial talus (49 %, OR 4.48). PTHI strongly predicted lack of occurrence of syndesmotic ligament injury (OR 19.6). The PTHI group had a high incidence of lateral ligamentous injury (78 %), but not significantly different from the control group (53 %). CONCLUSIONS: PTHI is strongly associated with injury involving the transverse tarsal joint complex. We hypothesize it results from talo-cuboid and/or talo-calcaneal impaction from a supination injury of the foot and ankle.

Intraosseous Schwannoma Involving Multiple Bones of the Foot: A Case Report.

We describe a rare case of intraosseous Schwannoma in the foot involving the tarsal navicular, cuboid, all 3 cuneiforms, and the second and third metatarsal bases in a 50-year-old female. Radiographs revealed a large, well-defined osteolytic lesion with endosteal scalloping and trabeculated contours at the margins. Intralesional excision, allograft bone implantation, and Kirschner wire fixation were performed. The histologic and immunohistochemical studies confirmed the diagnosis of Schwannoma. The distinctive radiographic features might have been the result of tumor spreading within the nutrient canals of the bones and direct compression of bone as the tumor enlarged. At the 18-month follow-up point, the patient had recovered well without recurrence. Intralesional excision produced a good functional outcome; however, extensive fusion surgery is recommended.

Tarsal Coalitions: Preliminary Results After Operative Excision and Silicone Sheet Interposition in Children.

Symptomatic tarsal coalitions that begin in early adolescence are usually treated by resection and interposition (fat, muscle, or bone wax) to prevent recurrence. The purpose of the present retrospective study was to describe our operative technique and report our clinical and radiologic outcomes with sterile silicone sheet interposition after resection of painful tarsal coalitions in 4 children (4 feet). The present series included 1 case of talocalcaneal synchondrosis and 3 of synostosis (2 talocalcaneal and 1 cuboid-navicular). Two validated functional scales were used to assess the patients' overall outcome and satisfaction with the procedure: the American Orthopaedic Foot and Ankle Society ankle-hindfoot score and the Foot Function Index. Conventional radiography, computed tomography with 3-dimensional reconstruction, and magnetic resonance imaging were performed at the final follow-up visit. The mean follow-up period was 40 (range 12 to 80) months. The mean age at surgery was 10.5 (range 8 to 13) years. All patients had achieved their desired activity level at 6 months postoperatively. The mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score was 93.5 (range 74 to 100), and the mean Foot Function Index was 3.25% (range 0% to 13%). No recurrence of the coalition on imaging at the final follow-up visit was observed in this patient series. Sterile silicone sheet interposition can be used to prevent recurrence of tarsal coalition in symptomatic tarsal coalitions after failure of conservative management.

Nonosseous Tarsal Coalition of the Lateral Cuneocuboid Joint: A Case Report.

We describe a rare case of a nonosseous coalition of the lateral cuneocuboid joint with peroneal spasm that we successfully treated with resection. A 60-year-old female had been experiencing constant pain in her right foot, particularly when walking and going up and down stairs. The pain had been present for approximately 1 year after she had experienced a minor injury. Her right ankle showed plantar flexion restrictions (right 20° and left 40°) and was held in an antalgic valgus position. Sudden passive plantar flexion produced pain behind the lateral malleolus of the right ankle. Tenderness was detected in the right peroneus brevis tendon and the right sinus tarsi. On plain radiographs, the oblique view showed an irregularity in the articular surface of the lateral cuneocuboid joint in both feet. On computed tomography images, there was no osseous continuation in the lateral cuneocuboid joint, indicative of a nonosseous bridge between the lateral cuneiform and the cuboid. The nonosseous coalition between the lateral cuneiform and the cuboid was resected and the trabecular surfaces and cortical margins covered with a thin film of bone wax. The patient's recovery was unremarkable, and 1 year after surgery, she was able to walk without pain and was able to perform her usual activities and job.