Ouessant: Flexible Integration of Dedicated Coprocessors in Systems On Chip

International audienceIntegration of hardware accelerators in System on Chips is often complex. When dealing with reconfigurable hard- ware, this greatly limits the attainable flexibility. In this paper, we propose an alternative approach to the Molen paradigm [1]. This approach, named Ouessant, is based on a very simple general purpose instruction set designed for close interaction with dedicated hardware accelerators. This instruction set is used to program a dedicated controler, which commands the accelerator's execution and data transfer with minimal CPU intervention. The resulting architecture is flexible, extensible, and can be easily integrated in System on Chips. Adding new accelerators is also made easier. Implementation of the architecture on different FPGA resources show very low footprint and a very small impact on attainable performance. Ouessant is freely available under an open-source license

Autoreloc: Automated Design Flow for Bitstream Relocation on Xilinx FPGAs

International audienceDynamic and partial reconfiguration of Field Programmable Gate Arrays (FPGA) enable to reuse logic resources for several applications which are scheduled in a sequential order or which are loaded on demand. A fraction of the design on the FPGA is then substituted by another logic function while the rest of the system on the chip stays unaffected. If a design provides several partial reconfigurable areas, the configuration bitstream representing the logic function to be configured in this region has to be adapted to the physical requirements of this chip area. This can be achieved by deploying a repository with all possible configuration bitstreams for all possible regions. It is obvious that storage space can quickly become a limiting parameter in reconfigurable designs. For this purpose, bitstream relocation provides a less storage greedy approach. Only one representation as bitstream of an application needs to be stored. During the configuration process, a relocation algorithm manipulates the bitstream in order to suit it to the respective reconfigurable area. However, reconfigurable regions have to fulfill strong constraints for a relocation to be possible, which makes the selection and placement of reconfigurable regions a complex process. Unfortunately this is not automated by tools so far. In this paper, an approach to automate the development of such relocatable bitstreams is presented along with new algorithms related to relocation specific steps. This approach results in functional designs with minimal intervention from the designer

Can Distal First Metatarsal Supination Osteotomy, Varization Osteotomy, or a Combination of Both Improve HV Surgical Outcomes? Preliminary Results of a Multicenter Randomized Control Trial

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: The outcomes of Hallux Valgus (HV) surgical treatment are perfectible. First ray dysmorphia in HV appears to incorporate a first metatarsal (M1) hyperpronation and a valgus deviation of M1 distal articular surface. Those could play a role in first ray destabilization and misalignment in HV. However, we do not know whether correction of these deformities could improve HV surgical treatment outcomes. Therefore, we performed a study to assess the impact of M1 distal supination osteotomy, M1 distal varization osteotomy, and combination of both on HV clinical and radiological outcomes. We hypothesized that M1 distal supination osteotomies would improve surgical outcomes in HV. Methods: We conducted an IRB-approved multicenter randomized control trial. HV with an indication for surgical correction were included. HV requiring surgery of the lesser metatarsals were excluded. Feet were randomly divided into 4 groups corresponding to 4 different types of surgery (Figure): 1. Control, classical M1 distal chevron. 2. Supination M1 distal chevron 3. Varization M1 distal chevron 4. Combination of the latter two. Preoperative evaluation and 6-months follow-up were performed. Demographics, AOFAS score, complications, and patient satisfaction (Likert Scale) were collected. On conventional weight-bearing radiographs before and 6 months after surgery, we measured the Hallux Valgus Angle(HVA), the Intemetatarsal Angle(IMA) the Distal Metatarsal Articular Angle(DMAA), the Okuda's M1 head shape classification(from round to angular) and the sesamoid position according to Hardy and Clapham. Normality of different variables was assessed using the Shapiro-Wilk test. Groups were compared using ANOVA for normal and Kruskall Wallis for nonnormal variables. Post-hoc pairwise analyses were performed with Dunn-Bonferoni’s test. Results: 100 HV were included. 8 were lost to follow-up. The Control (n=24), Supination (n=20), Varization (n=26) and Combination (n=22) groups were comparable on age, gender, BMI, and preoperative radiological parameters. At 6 months, there was no difference on AOFAS improvement (p=0.39) and patients satisfaction (p=0.14) whereas there were significant differences on HVA (p 15°) were present in 5 cases in Control (20.8%), and 2 in Varization (7.7%). Asymptomatic Hallux Varus (HVA < 0°) were present in 4 cases in Combination (18.2%), and 1 in Supination (5%). Conclusion: Distal M1 supination osteotomies showed better improvement in radiological parameters without showing clinical benefit. The combination of supination and varization osteotomies could lead to overcorrection while the classic M1 distal chevron could lead to insufficient corrections. Routinely performing a supination osteotomy in HV surgical management may lead to erroneous correction and we recommend an à la carte treatment. These results are preliminary and we recommend more patients and longer follow-up to confirm these findings

Evaluation of Chronic Lateral Ankle Instability with a Sprain Stimulator: A Controlled Study in Physically Active Subjects

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: Chronic Lateral Ankle Instability (CLAI) represents a significant socioeconomic burden. Paradoxically, its management has changed little over the years, notably because research is divided into functional and mechanical instability, whereas CLAI encompasses both. Sprain simulators can encompass both functional and mechanical instability by assessing the maximal ankle inversion velocity (MIV) during a simulated inversion trauma. We built a sprain simulator capable of producing a sudden ankle inversion motion during walking. We aimed to differentiate subjects with chronic lateral ankle instability (CLAI) from controls and quantify functional CLAI as well as impairments in activities of daily living and sports using a sprain simulator. Methods: Forty-five physically active subjects were included and assigned to a CLAI group, a control group, or excluded according to the International Ankle Consortium selection criteria. Each subject walked on a treadmill with instability boots after completing the Identification of Functional Ankle Instability (IdFAI) and the Foot Ankle Ability Measurement (FAAM) questionnaires. A simulated trauma was unexpectedly triggered by the observer. Maximal inversion velocities (MIV) were measured at this very moment using inertial moment units. We normalized these values by the average MIV of the 5 stance phases of the same foot preceding the simulated trauma (Ratio MIV). Normality of data were assessed with the Shapiro-Wilk test. The groups were compared using Student T test for normal and Mann-Whitney U test for nonnormal variables. Multivariate linear regressions were performed to assess the relation between, the IdFAI, the FAAM Activities of Daily Living Subscale, the FAAM Sports Subscale and the explanatory variables. Results: Twenty-six ankles were excluded, 32 composed the CLAI group and 32 the control group. Mean MIV were 213.5+/-54.7°/s and 177+/-64.2°/s (p=0.02), and mean Ratio MIV were 1.22+/-0.13 and 1.08+/-0.08 (p < 0.001) in the CLAI and Control groups respectively. In multivariate analysis, Ratio MIV was associated with higher values of IdFAI (β=42.8 [12.9;72.8],p=0.006), lower values of FAAM Activities of Daily Living Subscale (β=-14.1 [-27.8;-0.5],p=0.04) and lower values of FAAM Sports Subscale (β=-7.2 [-13.7;- 0.6],p=0.03) whereas MIV was not. Conclusion: Inversion velocities caused by a sprain simulator clearly differentiated CLAI from controls in our study. Ratio MIV showed good ability to quantify functional CLAI as well as impairments in activities of daily living and sports. This tool should be used in future studies in an attempt to provide a complete picture of CLAI encompassing its functional and mechanical aspects which may lead to improved LAS and CLAI management

Patients' point of view on the long-term results of total ankle arthroplasty, tibiotalar and tibiotalocalcaneal arthrodeses

Introduction: Total ankle arthroplasty (TAA), tibiotalar (TT) arthrodesis and tibiotalocalcaneal (TTC) arthrodesis are common surgical procedures that are sometimes concurrent. The functional results of TTC are deemed to be inferior because of the double joint sacrifice. Patient-Reported Outcome Measures (PROMs), as well as satisfaction scores, are commonly used to assess the outcome of these surgeries, but lack at capturing patients' ability to cope with potential functional limitations. The objective of our study was to compare the results of TAA, TT and TTC arthrodeses according to patients' point of view. We proposed two hypotheses: 1) TAA confer better results than TT arthrodeses, 2) and TT arthrodeses confer better results than TTC arthrodeses, on this specific criterion. Material and methods: We carried out a retrospective study integrating all TAA, TT and TTC arthrodeses performed in our center from 2010 to 2017. These surgeries were compared using PROMs (Foot Function Index (FFI), Foot and Ankle Outcome Scale (FAOS) and 12-Item Short Form Survey (SF-12)), a satisfaction rating and self-reported perceived recovery state. Results: Fifty-one patients were included in the TAA group, 50 in the TT group and 51 in the TTC group. The mean duration of follow-up was 46±20.8 months. The TAA group had better results than the TT group regarding the FFI score and satisfaction, thus confirming our primary hypothesis. On the other hand, no significant difference was found between the TT group and the TTC group, which invalidated our secondary hypothesis. No significant difference between the groups was found regarding the distribution of patients' perceived recovery state. Conclusion: Our hypothesis was not confirmed. In fact, TAAs, TT and TTC arthrodeses presented substantially similar results. Although it is difficult to compare surgeries with different indications, it is surprising to find that the patients' perceived recovery state, deviating from the usual clinical and radiological results, are relatively similar. Level of evidence: IV; Retrospective study

Outcomes of Hindfoot Joint-Sparing Reconstructive Procedures for Flexible Progressive Collapsing Foot Deformity: A Prospective Cohort Study

Category: Hindfoot; Other Introduction/Purpose: Treatment of Progressive Collapsing Foot Deformity (PCFD) is controversial and surgical procedures utilized usually depend on the type and rigidity of deformities present (PCFD classes and stages), degree of soft tissue involvement, and surgeon’s preference. Multiple surgical procedures are usually performed concomitantly to achieve adequate correction. Prospective data regarding the utilization of hindfoot joint-sparing reconstructive procedures in the treatment of flexible PCFD is scarce, and little is known about the influence of the different procedures utilized to treat PCFD in deformity correction and patient-reported outcomes (PROs). The objective of this prospective study was to evaluate the most used hindfoot joint-sparing procedures utilized by a single-surgeon to treat flexible PCFD, and the influence of the utilized procedures in deformity pattern corrections, and PROs. Methods: IRB-approved, prospective, and comparative cohort study. Adult PCFD patients with flexible deformity (stage 1), no history of surgical treatment, and that failed conservative treatment for >3-months were enrolled. Patients underwent surgical treatment by a single-surgeon. Patients were excluded if a hindfoot fusion procedure was needed intra-operatively to achieve correction. Types, numbers, and sizes of surgical procedures utilized were recorded. Weight-bearing CT (WBCT) measurements of overall 3D deformity, Classes A (hindfoot valgus), B (abduction), C (medial column instability), D (peritalar subluxation), and E (ankle valgus tilt) were assessed preoperatively, and at first 3-months WBCT. PROs were recorded preoperatively and at the most recent follow-up. Descriptive statistics were used to report the frequency of deformity and procedures utilized. Pre and postoperative measurements and PROs were compared with paired T-tests/Wilcoxon. Multivariate regression analysis was used to correlate procedures utilized with deformity correction and PROs. P-values of >0.05 were considered significant. Results: A total of 29 patients included (28 feet, 79%F, 21%M), mean age and BMI of respectively 47.6-years and 34kg/m 2 . Average number of procedures performed was five and mean follow-up was 19.1 months (range, 3 to 40). Frequency and sizes of medial displacement calcaneal osteotomy (MDCO), first ray plantarflexion procedure (Cotton/LapiCoton), and lateral column lengthening (LCL) procedures were, respectively: 100% (8.9mm displacement), 100% (66% Lapicotton/34% Cotton, 8.3mm wedge-opening) and 39% (6.8mm wedge-opening). Soft-tissue procedures performed: 83% Posterior tibial tendon (re-tensioning/FDL transfer/allograft reconstruction), 34% peroneal tendon (brevis-to-longus and brevis lengthening), 76% gastrocnemius-recession, 38% spring ligament (re-tensioning/reconstruction/augmentation) and 31% deltoid ligament (re- tensioning/reconstruction/augmentation). Significant improvement postoperatively was observed in all PCFD measurements performed and PROs (Figure). However, no direct correlation was found between procedures performed/measurement improvements and PROs. Conclusion: In this prospective comparative cohort study of flexible PCFD patients undergoing surgical treatment with hindfoot joint sparing surgical procedures, we observed significant postoperative improvement in all deformity patterns assessed (Classes A, B, C, and D) as well as PROs. MDCO and first ray plantarflexion procedures (Cotton or LapiCotton) were the most commonly utilized procedures and were performed in all cases. Even though deformity correction and PRO improvements were observed postoperatively, no direct correlation was observed between PROs and specific surgical procedures performed or deformity pattern corrections (PCFD classes)

Prevalence of Progressive Collapsing Foot Deformity in Hallux Valgus Patients

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Hallux valgus (HV) and progressive collapsing foot deformity (PCFD) are very common foot and ankle conditions in the adult population. Both could potentially disrupt the tripod construct of the foot which leads to chronic pain and arthritis. Several procedures were described to address HV deformity depending on deformity characteristics. PCFD could alter the management plan for HV if they occur simultaneously. The aim of this study was to detect the prevalence of PCFD in HV patients and study the frequency of individual PCFD classes. Methods: In this retrospective IRB approved study, patients > 18 years old who were evaluated for symptomatic hallux valgus and had a weight bearing computed tomography (WBCT) imaging were included. Patients were considered for further analysis if they have a hallux valgus angle (HVA) > 15° or inter-metatarsal angle (IMA) > 9°. All relevant demographic data were extracted. Two fellowship trained foot and ankle orthopaedic surgeon measured the following parameters: foot and ankle offset (FAO%) (Class A), talo-navicular coverage angle (TNCA) (Class B), Meary’s angle (Class C) and middle facet subluxation (MFS%) (Class D). Cases that showed FAO% > 4.6% and MFS% > 28.7% were diagnosed as PCFD. The prevalence of PCFD classes (A,B,C and D) was calculated using threshold values for its respective radiographic marker. Descriptive statistics were performed. Results: Thirty-four cases were included. 16 cases were females (46.06%) and 16 (46.06%) were right side. The average age was 52.51 years (SD ± 17.75), the average BMI was 30.14 (SD ± 7.15). The average HVA was 26.82 (SD ± 9.98) and the average IMA was 15.41 (SD ± 3.53). 13 patients (38.24%) had MFS% and FAO% above the threshold values. The average FAO was 4.75% (SD ± 4.92) and the average MFS was 29.17% (SD ± 15.89). Prevalence of Class A (FAO%) was 20 (58.82%), Class B (TNCA) was 12 (35.29%), Class C (Meary’s angle) was 15 (44.12%) and Class D (MFS%) was 16 (47.06%). Conclusion: Progressive collapsing foot deformity is prevalent in the hallux valgus population (38.24%). Class C which indicates medial column instability was prevalent in 44.12% of the cases. Given this high prevalence of PCFD, we believe that in addition to the classic hallux valgus parameters, PCFD classes evaluation could favor a surgical approach over another such as first tarsometatarsal joint procedures over isolated distal first metatarsal procedures to correct the HV deformity and simultaneously halt PCFD progression