Arm Thumb Research Articles

RVAM16: a low-cost multiple-ISA processor based on RISC-V and ARM Thumb

RVAM16: a low-cost multiple-ISA processor based on RISC-V and ARM Thumb

Ligament Suspensionplasty With Suture Tape Augmentation​ for Basal Thumb Arthritis.

Thumb carpometacarpal arthritis is common with aging, more common in women than men, and usually occurs after age 40. If a patient fails conservative treatments such as splinting, medications, and corticosteroid injections, then surgical intervention may be appropriate. Currently, there is no consensus on the best surgical treatment. By limiting metacarpal subsidence, ligament suspensionplasty with suture tape augmentation offers great pain relief, excellent functional outcomes, and limited postoperative immobilization. With this technique, trapeziectomy is first performed. A portion of the abductor pollicis longus tendon is resected and loaded onto the SwiveLock anchor using 4-0 FiberLoop, in addition to suture tape. The prepared graft and tape construct is anchored into the lateral first metacarpal (MC) base and index metacarpal base. After surgery, patients are put in a short arm thumb spica splint, interphalangeal (IP) joints free. Active motion is initiated at the first postoperative visit, usually within 1 week. All patients who had thumb arthritis treated with carpometacarpal suspensionplasty and suture tape augmentation between 2015 and 2022 by a single hand surgeon at our institution were queried. A total of 110 patients were invited to take part in this study, and 61 patients consented and were included in this study. Mean last in-office follow up was at 7.5±4.0 months, which showed significant improvements in pinch strength (P=0.011). A survey taken at a mean 2.8±1.3 years (range: 0.5 to 5.2y) after surgery reports a postoperative DASH score of 7.3±7.7 (range: 0 to 23.3), and VAS pain score of 0.7±1.1 (range: 0 to 5).

User-directed Assembly Code Transformations Enabling Efficient Batteryless Arduino Applications

The time for battery-free computing is now. Lithium mining depletes and pollutes local water supplies and dead batteries in landfills leak toxic metals into the ground[20][12]. Battery-free devices represent a probable future for sustainable ubiquitous computing and we will need many more new devices and programmers to bring that future into reality. Yet, energy harvesting and battery-free devices that frequently fail are challenging to program. The maker movement has organically developed a considerable variety of platforms to prototype and program ubiquitous sensing and computing devices, but only a few have been modified to be usable with energy harvesting and to hide those pesky power failures that are the norm from variable energy availability (platforms like Microsoft's Makecode and AdaFruit's CircuitPython). Many platforms, especially Arduino (the first and most famous maker platform), do not support energy harvesting devices and intermittent computing. To bridge this gap and lay a strong foundation for potential new platforms for maker programming, we build a tool called BOOTHAMMER: a lightweight assembly re-writer for ARM Thumb. BOOTHAMMER analyzes and rewrites the low-level assembly to insert careful checkpoint and restore operations to enable programs to persist through power failures. The approach is easily insertable in existing toolchains and is general-purpose enough to be resilient to future platforms and devices/chipsets. We close the loop with the user by designing a small set of program annotations that any maker coder can use to provide extra information to this low-level tool that will significantly increase checkpoint efficiency and resolution. These optional extensions represent a way to include the user in decision-making about energy harvesting while ensuring the tool supports existing platforms. We conduct an extensive evaluation using various program benchmarks with Arduino as our chosen evaluation platform. We also demonstrate the usability of this approach by evaluating BOOTHAMMER with a user study and show that makers feel very confident in their ability to write intermittent computing programs using this tool. With this new tool, we enable maker hardware and software for sustainable, energy-harvesting-based computing for all.

Isolated Partial Carpal Scaphoid Dislocation: A Case Report

Scaphoid dislocation is an uncommon entity of the carpal injuries that has been rarely reported in the literature. We report a case of a 41-year-old right-handed male who presented with a partial palmar scaphoid dislocation following a motor vehicle accident. Closed reduction was successfully performed and an immobilization by a short arm thumb cast has been maintained for 6 weeks. The last follow-up X-rays showed no evidence of redislocation, malunion or avascular necrosis. Our patient returned to his daily activities without any limitations. This case report emphasizes the importance of early diagnosis and orthopedic treatment for improved prognosis.

On-Demand Remote Software Code Execution Unit Using On-Chip Flash Memory Cloudification for IoT Environment Acceleration

In an Internet of Things (IoT)-configured system, each device executes on-chip software. Recent IoT devices require fast execution time of complex services, such as analyzing a large amount of data, while maintaining low-power computation. As service complexity increases, the service requires high-performance computing and more space for embedded space. However, the low performance of IoT edge devices and their small memory size can hinder the complex and diverse operations of IoT services. In this paper, we propose a remote on-demand software code execution unit using the cloudification of on-chip code memory to accelerate the program execution of an IoT edge device with a low-performance processor. We propose a simulation approach to distribute remote code executed on the server side and on the edge side according to the program’s computational and communicational needs. Our on-demand remote code execution unit simulation platform, which includes an instruction set simulator based on 16-bit ARM Thumb instruction set architecture, successfully emulates the architectural behavior of on-chip flash memory, enabling embedded devices to accelerate and execute software using remote execution code in the IoT environment.

Arthroscopic Thermal Shrinkage: A Novel Method for the Treatment of Chronic Volar Plate Instability at the Metacarpal Phalangeal Joint of the Thumb.

Background: Chronic volar plate instability of the thumb metacarpal phalangeal joint (MCPJ) is a disabling clinical problem. Patients usually present with pain and disability in terms of reduction in pinch and grip power. Numerous surgical techniques have been described for the treatment of this condition. Here we describe a novel method for the treatment of this condition by thermal shrinkage of the volar plate via thumb MCPJ arthroscopy. Methods: A retrospective review of 8 patients with chronic thumb MCPJ volar plate instability treated with the novel technique of thermal shrinkage of the volar plate via thumb MCPJ arthroscopy. The primary outcome is maintenance of saggital plane stability at the thumb MCPJ. Secondary outcomes include pinch and grip power, The Disabilities of the Arm, Shoulder and Hand (DASH) Score and thumb MCPJ range of movement. The duration of follow up and complications were also reviewed. Results: The mean follow up period was 41.4 months (range, 2-134 months). One case had recurrence of instability requiring open volar plate capsulodesis. All other cases had their thumb hyperextensibility resolved and maintained throughout the entire follow up period, up to 134 months for the case with the longest duration of follow up. Conclusions: Preliminary results suggest this novel, minimally invasive technique for the treatment of thumb MCPJ volar plate instability is effective and the long term follow up results are durable.

TrABin: Trustworthy analyses of binaries

Verification of microkernels, device drivers, and crypto routines requires analyses at the binary level. In order to automate these analyses, in the last years several binary analysis platforms have been introduced. These platforms share a common design: the adoption of hardware-independent intermediate representations, a mechanism to translate architecture dependent code to this representation, and a set of architecture independent analyses that process the intermediate representation. The usage of these platforms to verify software introduces the need for trusting both the correctness of the translation from binary code to intermediate language (called transpilation) and the correctness of the analyses. Achieving a high degree of trust is challenging since the transpilation must handle (i) all the side effects of the instructions, (ii) multiple instruction encodings (e.g. ARM Thumb), and (iii) variable instruction length (e.g. Intel). Similarly, analyses can use complex transformations (e.g. loop unrolling) and simplifications (e.g. partial evaluation) of the artifacts, whose bugs can jeopardize correctness of the results. We overcome these problems by developing a binary analysis platform on top of the interactive theorem prover HOL4. First, we formally model a binary intermediate language and we prove correctness of several supporting tools (i.e. a type checker). Then, we implement two proof-producing transpilers, which respectively translate ARMv8 and CortexM0 programs to the intermediate language and generate a certificate. This certificate is a HOL4 proof demonstrating correctness of the translation. As demonstrating analysis, we implement a proof-producing weakest precondition generator, which can be used to verify that a given loop-free program fragment satisfies a contract. Finally, we use an AES encryption implementation to benchmark our platform.

Reducing calling convention overhead in object-oriented programming on embedded ARM thumb-2 platforms

This paper examines the causes and extent of code size overhead caused by the ARM calling convention in Thumb-2 binaries. We show that binaries generated from C++ source files generally have higher amounts of calling convention overhead, and present a binary file optimizer to eliminate some of that overhead. Calling convention overhead can negatively impact power consumption, flash memory costs, and chip size in embedded or otherwise resource-constrained domains. This is particularly true on platforms using "compressed" instruction sets, such as the 16-bit ARM Thumb and Thumb-2 instruction sets, used in virtually all smartphones and in many other smaller-scale embedded devices. In this paper, we examine the extent of calling convention overhead in practical software, and compare the results of C and C++ programs, and find that C++ programs generally have a higher percentage of calling-convention overhead. Finally, we demonstrate a tool capable of eliminating some of this overhead, particularly in the case of C++ programs, by modifying the calling conventions on a per-procedure basis.

Region-based dual bank register allocation for reduced instruction encoding Architectures

In embedded systems, small code size is important due to memory constraints. One technique to achieve a small code size is reducing the instruction encoding from 32-bit to 16-bit, such as the ARM THUMB or MIPS-16 architectures. This half-size encoding leads to shorter register operands, making fewer registers available for register allocation and causing more spills, although invisible registers can be used as spill locations via copies. We propose reconstructing the original register file into dual-banks, added with the bank toggle instruction for bank changes and the inter-bank copies between the banks. We also propose an efficient dual-bank register allocation technique based on regions in the code to reduce spills. As a case study, we applied our banked register allocation model for the THUMB architecture. We found that the code size decreases by as much as 8% (5.8% on average) while the performance improves by as much as 11.1% (3.3% on average). Our results indicate that we would better organize the register file of an embedded CPU that can provide reduced encoding into dual banks for better quality of register allocation, rather than using the invisible registers for spills.

The effects of below-elbow immobilization on driving performance

IntroductionThere is limited research to guide physicians and patients in deciding whether it is safe to drive while wearing various forms of upper extremity immobilization. The purpose of this study is to evaluate the effect of below-elbow removable splints and fiberglass casts on automobile driving performance. Methods20 healthy subjects completed 10 runs through a closed, cone-marked driving course while wearing a randomized sequence of four different types of immobilization on each extremity (short arm thumb spica fiberglass cast, short arm fiberglass cast, short arm thumb spica splint, and short arm wrist splint). The first and last driving runs were without immobilization and served as controls. Performance was measured based on evaluation by a certified driving instructor (pass/fail scoring), cones hit, run time, and subject-perceived driving difficulty (1–10 analogue scoring). ResultsThe greatest number of instructor-scored failures occurred while immobilized in right arm spica casts (n=6; p=0.02) and left arm spica casts (n=5; p=0.049). The right arm spica cast had the highest subject-perceived difficulty (5.2±1.9; p<0.001). All forms of immobilization had significantly increased perceived difficulty compared to control, except for the left short arm splint (2.5±1.6; p>0.05). There was no significant difference in number of cones hit or driving time between control runs and runs with any type of immobilization. ConclusionsDrivers should use caution when wearing any of the forms of upper extremity immobilization tested in this study. All forms of immobilization, with exception of the left short arm splint significantly increased perceived driving difficulty. However, only the fiberglass spica casts (both left and right arm), significantly increased drive run failures due to loss of vehicle control. We recommend against driving when wearing a below-elbow fiberglass spica cast on either extremity.

Is Casting for Non-Displaced Simple Scaphoid Waist Fracture Effective? A CT Based Assessment of Union.

Objective:The purpose of this study is to report the union rate and time to union for acute non-displaced scaphoid waist fractures treated with a short arm thumb spica cast.Methods:A database was searched (2006-2013) to identify acute undisplaced scaphoid waist fractures. Cases that were not given a trial of casting were excluded (n=33). X-rays, CT scans and health records for each patient were reviewed to extract data.Results:172 patients met inclusion criteria. There were 138 males, 34 females, the mean age was 30 ± 16 years. The union rate was 99.4% (1 nonunion/172 subjects). The mean time to union was approximately 7.5 weeks (53 ± 37 days). Energy of injury, age or gender did not affect union rates or time to union. Cysts did not affect the union rate (p=0.73) but patients with cystic resorption along the fracture line required approximately 10 weeks for union (69 ± 60 days) compared to 7 weeks (51 ± 34 days) for those without cysts (p=0.05). Diabetes did not affect the union rate (p=0.81) but was found to increase the risk of delayed union (p=0.05). There was a weak, but statistically significant correlation between the number of days before the fracture was casted and the length of time needed to achieve union (r=0.27, p=0.001).Conclusion:Non-displaced scaphoid waist fractures have a high healing rate with appropriate identification and immobilization. Follow-up CT scans to assess healing can identify union within a shorter time frame (~7 weeks) than previously reported in the literature.

P141. Neuralgic amyotrophy associated with Hepatitis E infection – A case report

Introduction The cause of neuralgic amyotrophy (NA; Parsonage–Turner syndrome) remains unknown, but different infections often precede NA, and an idiopathic autoimmune response generating nerve inflammation has been postulated. Hepatitis E virus (HEV) infections are endemic in developing countries (genotypes 1 & 2). Within the last years, an increasing number of locally acquired HEV infections have been described in western countries (genotypes 3& 4). We present here the case of a previously healthy 37years old male with NA associated to autochthonous HEV infection, presumably caused by a meal of raw pork one week before symptom onset. Case report Admission was due to bilateral arm and upper spine pain with paraesthesia of both upper extremities. Previous orthopaedic presentation ruled out vertebral disk herniation, myelopathy and foraminal stenosis by Magnetic Resonance (MR) Imaging. Neurological examination revealed right-sided scapula alata and palsies of arm abduction, elbow flexion/extension, thumb opposition and finger splaying. Numbness was present on the radial side of both forearms. Right-sided biceps and triceps reflexes were reduced; Tromner's reflex was absent. Sensible and motoric nerve conduction velocity (NCV) of the median and radial nerve, F-wave examinations, sympathic skin reflex (SSR) and electromyography (EMG; anterior serratus and deltoid muscle) were normal. Liver enzymes were elevated: AST 325 U/L, ALT 1774 U/L, AP 304 U/L, GGT 205 U/L. Cerebral spinal fluid (CSF) revealed lymphomonocytic pleocytosis (14cells/μl), signs of blood–brain–barrier disruption and elevated protein (77.6mg/dl) with normal lactate and glucose levels. CSF HEV-, HSV-, VZV-PCR and Borellia IgM were negative. Further tests ruled out Treponema pallidum, Rubella, Rubeola, Mumps, TBE (tick borne encephalitis), Hepatitis A,B,C, HIV, CMV and EBV. Serum-HEV-RNA was positive (8.3×10 4 cop/ml; genotype 3c). Assuming HEV-associated NA, oral administration of methylprednisolone was started (80mg, tapering thereafter), and patient's pain remarkably decreased. High resolution magnetic resonance neurography (3Tesla) after two months revealed fascicular T2 hyperintense lesions of the ulnar, radial and median nerves and brachial and triceps muscle denervation. Clinical follow-up examination showed typical findings of a Parsonage–Turner syndrome with atrophy of the right upper arm muscles, (improved) scapula alata and palsies of elbow flexion, thumb opposition, flexion and finger splaying. Bilateral hypaesthesia on radial side of forearms persisted. Arm abduction and elbow extension improved. NCV, SSR and F-wave were again normal. However, EMG (abductor digiti minimi, flexor pollicis longus, flexor digitorum superficialis muscles) now discovered denervation. Conclusions NA is rare and association with Hepatitis E infections have been described in single patients. While diagnosis can be difficult, clinicians should consider this sporadic entity, particularly when typical neurologic signs are combined with elevated liver enzymes.

Transscaphoid–transtriquetral–transhamate perilunate fracture–dislocation: case report

A transscaphoid–transtriquetral–transhamate perilunate fracture–dislocation is a very rare pattern of injury among the known spectrum of perilunate dislocations and perilunate fracture–dislocations, and the details of the initial treatment and outcome of this injury have never been reported. We present the case of a 24-year-old, right-handed man, who presented in the emergency department with acute fracture at the waist of the scaphoid, fracture avulsion at the proximal pole of the triquetrum, and fracture of the hamate body with an associated dorsal perilunate dislocation after a fall from 3 m onto his outstretched left hand. Under general anesthesia, closed reduction was attempted with axial traction. After anatomical reduction was achieved, osteosynthesis of the scaphoid was performed using a cannulated screw, and after this was done, percutaneous pinning of the hamate with a K-wire and reconstruction of the scapholunate ligament was performed using an anchor for reinforcement of the scapholunate ligament through a minimally invasive volar approach. A short arm thumb cast splint was applied for 4 weeks, and part-time splinting was continued for another additional 4 weeks. The patient subsequently underwent 3 months of intensive range-of-motion and muscle-strengthening exercises. At the final follow-up examination, 60 months after the initial operation, the range of motion of the left wrist was 145° (extension plus flexion arc), and grip strength, 47 kg, were 91 and 98 % of the values for the unaffected wrist, respectively. Radiographs showed a bony union of the scaphoid, triquetrum, and hamate, and no sign of avascular necrosis in the proximal scaphoid fragment, as well as other carpal bones. No midcarpal or radiocarpal degenerative arthritis was observed, and the normal carpal bone relationships were still maintained, with a scapholunate angle of 49° and a scapholunate distance of 1.5 mm. We recommend closed reduction and minimally invasive volar approach for screw fixation of the scaphoid, as well as percutaneous pinning of the hamate in this case and reconstruction of the disrupted carpal ligaments to minimize the interruption of the blood supply to the carpus and also to obtain rigid fixation during the procedure.

Epidermoid Cyst on Top of the Left Arm Thumb

Epidermoid Cyst on Top of the Left Arm Thumb

Fracture du scaphoïde carpien associée à une fracture de l’extrémité inférieure du radius chez l’enfant. À propos de deux cas

The authors report two cases of concomitant scaphoid and distal radial fractures, a rare combination of lesions in children. The first case was in a 14-year-old boy who presented a midscaphoid fracture associated with a distal forearm fracture. The second case concerned a 13-year-old boy who presented a midscaphoid fracture associated with a Salter type II distal radial fracture. Both fractures were reduced under general anaesthesia. The total period of immobilisation was 3 months, using a large arm thumb cast. Associated scaphoid fractures should be suspected with all types of distal forearm injuries in children. Reduction of the radius fracture should be done carefully to avoid possible displacement of the scaphoid fracture.

Does Thumb Immobilization Contribute to Scaphoid Fracture Stability?

Immobilization protocols for nondisplaced scaphoid fractures have included the elbow, wrist, and thumb. This study attempts to demonstrate whether or not immobilization of the thumb makes a difference in preventing motion at the scaphoid fracture site. Using six fresh frozen forearm specimens, a transverse waist scaphoid fracture was created through a dorsal approach. Metallic markers were imbedded on either side of the fracture. Sutures were secured to the flexor pollicus longus (FPL) and extensor pollicus longus (EPL). Each specimen was loaded in extension and flexion by attaching 50-g weights to the EPL and FPL, first with no casting, then with a short arm cast, and finally a short arm thumb spica cast. Angulation and displacement at the fracture site were measured in the coronal, sagittal, and axial planes utilizing image reconstructions from computed tomography. One-way ANOVA with repeated measures and Tukey-Kramer multiple comparison test post hoc analysis were used for statistical evaluation. There was no significant difference in fracture angulation or rotation between spica and short arm casts. There was a significant difference in angulation and rotation in all three planes when comparing between casting and no casting, p < 0.05. In our cadaveric model, wrist immobilization is crucial for nondisplaced scaphoid waist fractures, and short arm casting was just as effective as thumb spica casting in preventing fracture displacement.

Expression-tree-based algorithms for code compression on embedded RISC architectures

Reducing program size has become an important goal in the design of modern embedded systems targeted to mass production. This problem has driven efforts aimed at designing processors with shorter instruction formats (e.g., ARM Thumb and MIPS16) or able to execute compressed code (e.g., IBM PowerPC 405), This paper proposes three code compression algorithms for embedded RISC architectures. In all algorithms, the encoded symbols are extracted from program expression trees. The algorithms differ on the granularity of the encoded symbol, which are selected from whole trees, parts of trees, or single instructions. Dictionary-based decompression engines are proposed for each compression algorithm. Experimental results, based on SPEC CINT95 programs running on the MIPS R4000 processor, reveal an average compression ratio of 53.6% (31.5%) if the area of the decompression engine is (not) considered.

SAMC: a code compression algorithm for embedded processors

In this paper, we present a method for reducing the memory requirements of an embedded system by using code compression. We compress the instruction segment of the executable running on the embedded system, and we show how to design a run-time decompression unit to decompress code on the fly before execution. Our algorithm uses arithmetic coding in combination with a Markov model, which is adapted to the instruction set and the application. We provide experimental results on two architectures, Analog Devices' Share and ARM's ARM and Thumb instruction sets, and show that programs can often be reduced by more than 50%. Furthermore, we suggest a table-based design that allows multibit decoding to speed up decompression.

Dorsal dislocation of the triquetrum: a rare complication of perilunate dislocation

A 1%year-old male student fell from a height of 5 m while rock climbing. He sustained, among other injuries, a trans-scaphoid perilunate dislocation of the left wrist (Figure I). Under general anaesthetic, the wrist was manipulated. The scaphoid was openly reduced and fixed with a Herbert screw and the wrist immobilized in a short arm thumb plaster of Paris cast. The postoperative X-rays were initially thought to be satisfactory but closer inspection showed an unusual bony structure on the dorsum of the carpus (Figure 2). This was, without doubt, one of the carpal bones but it was not immediately certain which bone was still dislocated.

Power staple fixation in trapeziometacarpal arthrodesis

Twenty-seven trapeziometacarpal arthrodeses were performed in 26 patients for basilar thumb joint arthritis utilizing power staple fixation. Short arm thumb spica cast immobilization was maintained for an average of 8 weeks, followed by part-time splintage for 6–12 weeks. Twenty patients were available for evaluation an average of 19 months after the operation. All of the patients were satisfied with the procedure. Thirteen had complete relief of pain, four had mild pain, and three had moderate pain after surgery. The two nonunions that occurred were in patients that refused postoperative casting and both had complete pain relief. There were no fixation-related complications in the remaining 18 patients that were casted postoperatively, and all developed a solid fusion. Power staple fixation in trapeziometacarpal arthrodesis has a 90% union rate with no long-term fixation related complications.