Stable Foot Research Articles

Force Balance Control and Optimization of the Quadruped Hydraulic Robot Based on Materials Structure Design

In this paper, in order to meet the requirements of stable foot support and balanced walking of quadruped hydraulic robot, a new control method is proposed. The "hard" contact between the feet of the quadruped hydraulic robot and the ground are changed into "semi flexible" contact to reduce the impact force produced by the contact and collision of the two and reduce the unbalance of the force. The designed "semi flexible" scheme was to coat the "semi flexible" modified polytetrafluoroethylene (PTFE) material on the surface of the bottom material of the robot's foot. The modification of PTFE was optimized by SRIM, and the optimization scheme was selected for experimental study to obtain the Al2O3/PTFE material for which the abrasive resistance met the requirement of robot motion. It was also used in robot force imbalance control experiment research optimization. The study clearly revealed that it can effectively reduce the power of the impact force caused by the contact and collision of the feet of the quadruped robot and the ground, reduce the swing and the unbalance of the motion force of the quadruped robot, and meet the requirements of the precise positioning and the force balance walking of the motion of quadruped hydraulic robot to a certain extent.

Prevalence of Proximal Tarsal Disruption in Lisfranc Fracture-Dislocations

Category: Midfoot/Forefoot Introduction/Purpose: Lisfranc fracture/dislocations comprise of spectrum of injury including simple disruption of the lisfranc articulation to more complex tarsometatarsal fracture/dislocations. A further known variant of lisfranc injuries involves proximal tarsal disruption, specifically through the articulation of the medial and middle cuneiform. In the absence of polytrauma and high energy injury it is unknown what proportion of patients with sport or primary axial loading injury have proximal medial column variants of the lisfranc fracture. Recognizing and stabilizing this disruption is critical to establishing a stable medial column and restoring appropriate biomechanics of the foot. Methods: After IRB approval a retrospective cohort of patients was established at a single instutition utilizing CPT codes consistent with fixation of lisfranc/tarsometatarsal fracture-dislocations. Surgical encounters over a 3 year period were identified and retrospective chart review of operative reports and independent evaluation of imaging was used to determine medial column/proximal variants within the included subset of patients. Low energy fracture mechanisms with adequate imaging and operative reports were included in the study. Results: A total of 52 low energy lisfranc fracture-dislocations were included in the study for evaluation of injury patter. Based on imaging studies, intra-operative findings and fixation modalities 30 medial column variants (58%) were identified in this cohort. This subset of patients showed instability through the medial ray extending proximal to the lisfranc articulation and requiring intercuneiform fixation. Conclusion: Tarsometatarsal fracture-dislocations represent a spectrum of injury from disruption of the lisfranc joint to multiple midfoot dislocations. A proximal variant of this injury pattern with intercuneiform disruption is often noted, but prevalence has not been established. In low energy tarsometatarsal fracture-dislocations this study notes a 58% prevalence of medial column disruption requiring additional proximal fixation. Recognizing this injury pattern and appropriately addressing the pathology is critical for obtaining a stable foot and favorable outcome.

Our Experience with Internal Fixation of Unstable Charcot Foot with Intramedullary Nail and Plate

Background: Charcot neuroarthropathy is potentially a limb-threatening disease, most commonly associated with diabetes mellitus. Early diagnosis is a key factor in the management and plays a central role in the prevention of severe deformity. Conservative treatment remains the gold standard for most patients with acute stage of the Charcot neuroarthropathy. Surgery is usually reserved for patients with severe or unstable deformities that are refractory to conservative treatment. The aim of this article is to provide a brief overview of the Charcot neuroarthropathy and to present our experience in surgical treatment of patients with this condition.Methods: 14 patients with Charcot neuroarthropathy and clinically unstable foot with a major dislocation in Lisfranc joint, stadius Eichenholz II, treated from January 2016 to September 2017 at University Medical Centre Ljubljana, were included in the study. Primary they were treated conservatively, until the acute edema, increased local temperature and redness were gone. All patients underwent an open reduction and internal fixation with plates or with intramedullary nails and plates.Results: Successful recovery was obtained in all 14 cases, achieving stable foot. No postoperative complications were observed during the follow-ups.Conclusion: Successful surgical treatment with internal fixation with plates or with intramedullary nail or plate, improved our patients quality of life. Based on our experience delayed open reduction and internal fixation of acute unstable Charcot foot is good and appropriate technique especially for patients without coexisting infections or macroangiopathy.

Changes in the characteristics of voluntary movements after long duration spaceflight

Changes in the characteristics of voluntary movements after long duration spaceflight

Sural Flap Use for the Treatment of Wounds With Underlying Osteomyelitis: Graft Size a Predictor in Outcome, a Systematic Review.

Therapeutic, Level III: Systematic review.

O2: Cluster analysis to identify foot motion patterns in children with flexible flatfeet – A statistical approach to detect decompensated pathology

The incidence of flatfoot is approximately 5% in children and adults. The symptomatic form of a flexible flatfoot produces subjective and objective complaints, including gait disturbances. Surgical intervention is considered when conservative management fails. The arthroereisis procedure provides a stable foot and durable correction. However, to the best of our knowledge, no study has evaluated the effectiveness of this procedure on gait parameters.Fifteen children with painful flatfeet (10 males; 5 females) with a mean age of 12 years and 6 months underwent the calcaneo stop procedure. Radiographic, gait analysis and functional measures were evaluated to assess the changes pre- and post-operatively.All children were followed up for a mean period of 4 years and 6 months. The overall results of the study exhibited statistically significant improvement for all radiographic variables, functional measures and range of motion investigated in the study (p < 0.05). Although the study showed improvement in all temporal parameters (p < 0.05) measured in the gait analysis, the results demonstrated there were no statistically significant differences in the kinematic and kinetic variables (p > 0.05) before and after surgery.Although there was no significant improvement in the kinematic and kinetic variables investigated, this study supports the calcaneo-stop procedure as a reliable and effective procedure for treating paediatric flexible flatfoot.

Effectiveness of surgically treated symptomatic plano-valgus deformity by the calcaneo stop procedure according to radiological, functional and gait parameters.

BackgroundThe incidence of flatfoot is approximately 5% in children and adults. The symptomatic form of a flexible flatfoot produces subjective and objective complaints, including gait disturbances. Surgical intervention is considered when conservative management fails. The arthroereisis procedure provides a stable foot and durable correction. However, to the best of our knowledge, no study has evaluated the effectiveness of this procedure on gait parameters.MethodsFifteen children with painful flatfeet (10 males; 5 females) with a mean age of 12 years and 6 months underwent the calcaneo stop procedure. Radiographic, gait analysis and functional measures were evaluated to assess the changes pre- and post-operatively.ResultsAll children were followed up for a mean period of 4 years and 6 months. The overall results of the study exhibited statistically significant improvement for all radiographic variables, functional measures and range of motion investigated in the study (p < 0.05). Although the study showed improvement in all temporal parameters (p < 0.05) measured in the gait analysis, the results demonstrated there were no statistically significant differences in the kinematic and kinetic variables (p > 0.05) before and after surgery.ConclusionsAlthough there was no significant improvement in the kinematic and kinetic variables investigated, this study supports the calcaneo-stop procedure as a reliable and effective procedure for treating paediatric flexible flatfoot.

Tibiocalcaneal arthrodesis using intramedullary nail for severe rigid equinovarus deformity in adults

Aim: To evaluate the results of tibiocalcaneal arthrodesis using intramedullary nails in adults with severe rigid equinovarus deformity of foot. Background: Foot is an amazing structure of support, balance, locomotion and sensibility. Impairment of one or more of these functions can lead to catastrophic sequelae. Equinovarus deformities of foot can be very disabling by marring the ambulation, daily activities, shoe wear and hygiene. In this paper we tend to share our experience of treating patients with posttraumatic severe rigid equinovarus deformities via tibiocalcaneal arthrodesis with retrograde intramedullary nailing. Settings and Design: Prospective follow up study. Materials and Methods: We selected 10 patients (3 females, 7 males) aged 18–60 years, suffering from disabling non-braceable posttraumatic severe rigid equinovarus deformity of foot. The patients were treated via tibiocalcaneal arthrodesis with retrograde intramedullary nailing and functional outcome was evaluated by comparing the preoperative and postoperative Kitaoka Patzer ankle arthrodesis scores and Mazur ankle arthrodesis scores. Statistical Analysis Used: SPSS program for Windows, version 17.0 (SPSS, Chicago, Illinois). Result: The comparison of the preoperative and postoperative scores showed significant improvement from poor to good after tibiocalcaneal arthrodesis was done in such patients. Conclusion: We can conclude that tibiocalcaneal arthrodesis using intramedullary nails is a good option to provide a stable plantigrade foot to the patient though further improvements in implant designs may bring better options.

Complication assessment and prevention strategies using midfoot fusion bolt for medial column stabilization in Charcot’s osteoarthropathy

In Charcot’s osteoarthropathy stabilization of the medial column of the foot was introduced in order to establish a stable foot and reduce the risk for amputation. This study was performed to analyze postoperative complications, define risk factors for those and develop strategies for prevention. Since bolt dislocation takes place frequently, it was aimed to predict an appropriate time point for bolt removal under the condition that osseous healing has occurred.Fourteen consecutive patients with neuroosteoarthropathy of the foot and arch collapse were treated with open reduction and stabilization using midfoot fusion bolt and lateral lag screws. Age, gender, presence of preoperative osteomyelitis or ulcer, number of complications and operative revisions, Hba1c value, consolidation of arthrodesis, presence of a load-bearing foot and period to bolt dislocation was assessed.The mean follow-up was 21.4±14.6 (mean±SDM) months, 64% of patients suffered from diabetes with a preoperative Hba1c of 8.5±2.4. The mean number of revisions per foot was 3.6±4.1. Bolt dislocation was seen in 57% of the patients following 11.3±8.5 months; in 75% of these patients bony healing occurred before dislocation. There was a significant association between preoperative increased Hba1c value, presence of preoperative ulcer and wound infection. Healing of arthrodesis was demonstrated in 57% and a permanent weight-bearing foot without recurrent ulcer was achieved in 79%.The early and late postoperative complications could be controlled in general. A fully load-bearing and stable foot was obtained, despite osseous consolidation was not detected in all of these cases. Once a stable foot has established early removal of fusion bolt should be considered. To decrease the risk of infection Hba1c should be adjusted and ulcers should be treated before the operation.

Microvascular Reconstruction in the Revascularised Diabetic Foot: A Perforosome Approach

Microvascular Reconstruction in the Revascularised Diabetic Foot: A Perforosome Approach

Prediction of complications in a high-risk cohort of patients undergoing corrective arthrodesis of late stage Charcot deformity based on the PEDIS score.

BackgroundAll diabetic neuroosteoarthropathy (Charcot arthropathy) treatment concepts are focused on a long-term infection-free, ulcer-free, and plantigrade sufficiently stable foot in order to avoid amputation. Reconstructive arthrodesis techniques for severe deformities are associated with high postoperative complication rates. This study reports a detailed complication analysis and provides a strategy that may help detect patients at risk for a complicated postoperative course.MethodsThe study comprised 43 feet in 37 patients with severe non-plantigrade or unstable Charcot deformity, Eichenholtz stages II/III (Sanders and Frykberg types II-V), who underwent reconstructive arthrodesis of the mid- and/or hindfoot. Patients were retrospectively enrolled 4.5 years postoperatively (range 1.8–11.2 years). All patients showed at least two out of five positive Pinzur high-risk criteria (immuno-compromising illnesses, large bone deformity, longstanding ulcer overlying infected bone, regional osteopenia, obesity). Follow-up included a detailed clinical analysis and radiologic assessment with emphasis on complication analysis and evaluation in accordance to the PEDIS classification system.ResultsSignificantly lower overall complication rates, as well as re-operation, reulceration and amputation counts were found for patients with a cumulative PEDIS count below 7. For PEDIS single criteria, significantly lower overall complication rates were found for patients without signs of occlusive peripheral artery disease, an ulcer extent <0.9 cm2, ulcer depth including erosion and inflammation of the skin and subcutaneous tissues only. Soft-tissue complications affected 49 % of patients, hardware breakage 33 %, hardware loosening 19 %, non-union 18 % and amputation 21 %. Radiographs revealed a correct reconstruction and restoration of all foot axes postoperatively with partial recollapse at the lateral foot column; however, fixation strength for the medial column was maintained.ConclusionsInternal corrective arthrodesis for patients within the deformed stages of Charcot deformity can provide adequate reconstruction, as assessed by intraoperative radiographic measures, that exhibit superior long-term stability for the medial column. Despite a high risk patient population, a favourable outcome in terms of overall complication, re-ulceration, and amputation rates for patients/feet with a cumulative PEDIS count below 7 was found. The cut-off value of 7 may aid clinical decision-making during preoperative planning for Charcot deformity.

Talectomy and tibiocalcaneal arthrodesis with intramedullary nail fixation for treatment of equinus deformity in adults.

Severe equinovarus foot deformity in adults is a challenging problem. Conservative treatment rarely is effective, and operative options are limited. The aim of this study was to evaluate the results of talectomy and tibiocalcaneal arthrodesis with intramedullary nail fixation for the treatment of severe equinovarus deformity in adults. Twelve patients (average age 39 years, range 15-70 years) with severe equinovarus deformities of the foot were treated with talectomy and tibiocalcaneal arthrodesis with intramedullary nail fixation between March 2010 and February 2013. Average follow-up was 20 months (range 10-37 months). Tibiocalcaneal fusion was achieved in all patients at an average of 12 weeks (range 8-17 weeks). Preoperatively, all patients had severe, irreducible equinovarus deformities; at last follow-up, almost all feet had mild residual deformity, but were plantigrade and did not require a brace or orthosis. The average AOFAS ankle score improved from 41.1 (range 8-66) preoperatively to 78.4 (range 67-86) postoperatively (P = .02). There was a similar improvement in the average VAS score from 6.3 (range 2-10) preoperatively to 0.8 (range 0-4) postoperatively (P = .02). The combination of talectomy and tibiocalcaneal arthrodesis was effective in correcting severe rigid equinovarus deformity in adults. Removal of the talus resulted in laxity of the soft tissues, making correction of the deformity easier. Tibiocalcaneal arthrodesis achieved a stable foot without the problems associated with talectomy alone. Level IV, case series.

The “footloose” mechanism: Iceberg decay from hydrostatic stresses

AbstractWe study a mechanism of iceberg breakup that may act together with the recognized melt and wave‐induced decay processes. Our proposal is based on observations from a recent field experiment on a large ice island in Baffin Bay, East Canada. We observed that successive collapses of the overburden from above an unsupported wavecut at the iceberg waterline created a submerged foot fringing the berg. The buoyancy stresses induced by such a foot may be sufficient to cause moderate‐sized bergs to break off from the main berg. A mathematical model is developed to test the feasibility of this mechanism. The results suggest that once the foot reaches a critical length, the induced stresses are sufficient to cause calving. The theoretically predicted maximum stable foot length compares well to the data collected in situ. Further, the model provides analytical expressions for the previously observed “rampart‐moat” iceberg surface profiles.

Synergistic interaction between ankle and knee during hopping revealed through induced acceleration analysis

The forces produced by the muscles can deliver energy to a target segment they are not attached to, by transferring this energy throughout the other segments in the chain. This is a synergistic way of functioning, which allows muscles to accelerate or decelerate segments in order to reach the target one. The purpose of this study was to characterize the contribution of each lower extremity joint to the vertical acceleration of the body’s center of mass during a hopping exercise. To accomplish this, an induced acceleration analysis was performed using a model with eight segments. The results indicate that the strategies produced during a hopping exercise rely on the synergy between the knee and ankle joints, with most of the vertical acceleration being produced by the knee extensors, while the ankle plantar flexors act as stabilizers of the foot. This synergy between the ankle and the knee is perhaps a mechanism that allows the transfer of power from the knee muscles to the ground, and we believe that in this particular task the net action of the foot and ankle moments is to produce a stable foot with little overall acceleration.

Wide-Pulse Electrical Stimulation to an Intrinsic Foot Muscle Induces Acute Functional Changes in Forefoot-Rearfoot Coupling Behaviour during Walking

Interventions for strengthening intrinsic foot muscles may be beneficial for rehabilitation from overuse injuries. In this study the acute effects of high-frequency, low-intensity wide-pulse electrical stimulation (WPS) over an intrinsic muscle on subsequent foot function during walking was assessed in healthy participants. WPS was delivered to the m. abductor hallucis (m.AH) of the non-dominant foot during relaxed standing. 3-dimensional forefoot (FF)--rearfoot (RF) coordination was quantified with a vector coding technique within separate periods of the stance phase to study WPS functional effects on foot motion. 4 types of coordinative strategies between the FF and RF were interpreted and compared PRE-to-POST-WPS for both the experimental and control feet. Bilateral electromyography (EMG) from m.AH was analysed during the intervention period for evidence of acute neuromuscular adaptation. The results showed that WPS significantly modulated FF-RF coordination during mid-stance, indicative of a more stable foot. Specifically, a statistically significant increase in FF eversion with concomitant RF inversion in the frontal plane and RF-dominated adduction in the transverse plane was observed. Subject-specific increases in post-stimulus m.AH EMG activation were observed but this was not reflected in an overall group effect. It is concluded that the structural integrity of the foot during walking is enhanced following an acute session of WPS and that this mechanical effect is most likely due to stimulation induced post-tetanic potentiation of synaptic transmission.

Rückfußvalgus

The clinical finding of flatfoot is characterized by a flattening of the medial longitudinal arch and valgus deformity of the hindfoot. The differential diagnosis of flatfoot is the physiological, flexible, contracted flatfoot, which occurs as a congenital or acquired deformity. Congenital flatfoot deformity requires early intensive therapy, while a flexible flatfoot in children has a good prognosis and conservative treatment usually leads to a stable and sufficient load-bearing foot. Severe flatfoot in children can be corrected successfully by simple, minimally invasive procedures. In adults with symptomatic flatfoot, which usually occurs due to an insufficiency of the tendon of the tibialis posterior, conservative therapy with insoles, shoe modifications and physiotherapeutic measures can lead to significant improvement, otherwise surgical correction is recommended. Early, stage-appropriate therapy helps to prevent an impending decompensation of the hindfoot.

Limb salvage for spreading midfoot osteomyelitis following diabetic foot surgery

Osteomyelitis is a challenging problem when it appears in the feet of patients with diabetes. Although the most frequent port of entry for bacteria is an ulcer, surgical wounds also permit entry of bacteria into the foot. This surgical complication may become limb-threatening, and treatment is a challenge. Here we present two cases of patients with neuropathic feet and palpable distal pulses, who were previously treated with surgery, and who presented with spreading bone infection in the midfoot. Pictures and radiological studies are shown. In both cases, bone infection caused severe destruction of the architecture of the midfoot, and the limbs of both patients were threatened. Midfoot osteomyelitis is associated with a higher rate of major amputations than osteomyelitis of the forefoot. Furthermore, meticillin-resistant Staphylococcus aureus was isolated in one of the cases. Our successful limb salvage approach was based on three steps: 1) removing the infected bone; 2) culture-guided antibiotic treatment; and 3) stabilizing the infected foot by means of total contact casting with openings resulting in a stable foot. To the best of our knowledge, there are no reports of the use of a total contact cast to stabilize an unstable and infected foot. Eight years (Case 1) and four years (Case 2) after complete healing, there were no recurrences of infection.

CAS-basierte Korrekturarthrodese des Lisfranc-Gelenks und Mittelfußes

Restoration of a stable and plantigrade foot in deformities at the midfoot (between the Chopart and tarsometatarsal (TMT) joint) and/or the TMT joint and concomitant degenerative changes. Deformities and concomitant degenerative changes at the midfoot and/or TMT joint. Active local infection or relevant arterial insufficiency. Supine position and dorsomedian and dorsolateral approach to the midfoot and TMT joint. Placement of dynamic reference bases (DRB) in the talus and distal shaft of the 1(st) metatarsal. Two-dimensional (2D) image acquisition for navigation. Definition of axes of the talus and 1st metatarsal, and of the extent of correction. Exposition of midfoot and TMT joints and removal of remaining cartilage. Transplantation of autologous, cancellous, and cortical bone if necessary. Computer-assisted surgery (CAS)-guided correction and internal fixation with 3.5mm screws (e.g. 3.5mm cortical screw, Synthes, Umkirch, Germany) and plates (e.g. 3.5mm LCDCP, Synthes, Umkirch, Germany). Three-dimensional (3D) image acquisition for analysis of the accuracy of the correction and implant position. Insertion of drains and layerwise closure. Partial weight bearing (15kg) in cast shoe for 6 weeks, followed by full weight bearing in a stable standard shoe. After 12weeks, pedography and production of insole orthoses based on the pedographic data. From September, 1(st) 2006 to September, 30(th) 2008, 32 correction arthrodeses at the midfoot/TMT joint were performed. The accuracy was assessed by intraoperative 3D imaging. All achieved angles/translations were within a maximum deviation of 2° when compared to the planned correction. Complications associated with CAS were not observed. In all 31cases without navigation failure, a timely fusion was observed.

Navigierte Korrekturarthrodese des oberen und unteren Sprunggelenks mit retrograder Marknagelfixierung

Restoration of a stable and plantigrade foot in deformities of the ankle and/or hindfoot and concomitant degenerative changes at the ankle and subtalar joint. Deformities of the ankle and/or hindfoot and concomitant degenerative changes at the ankle and subtalar joint. Active local infection or relevant arterial insufficiency. Prone position and posterolateral approach to ankle and subtalar joint. Placement of dynamic reference bases (DRB) in the tibia and through a stab incision in the talus or calcaneus. Two-dimensional (2D) image acquisition for navigation. Definition of axes of the tibia, calcaneus, and hindfoot, and of extent of correction. Exposition of ankle and subtalar joint and removal of remaining cartilage. Computer-assisted surgery (CAS)-guided correction and transfixation of the corrected position with 2.5 mm K-wires. Three-dimensional (3D) image acquisition for analysis of the accuracy of the correction and planning of the drilling for the retrograde nail. CAS-guided drilling insertion of the nail. Insertion of locking screws in the calcaneus, talus and tibia. 3D image acquisition for analysis of the accuracy of the correction implant position. Partial weight bearing (15 kg) in an orthosis (Vacuped) for 6 weeks, followed by full weight bearing in a stable standard shoe. From 1 September 2006 to 31 August 2008, 14 correction arthrodeses were performed. The accuracy was assessed by intraoperative 3D imaging. All achieved angles/translations were within a maximum deviation of 2°/mm when compared to the planned correction. Complications that were associated with CAS were not observed. In all 14 cases completing follow-up, timely fusion was registered.

Ankle Fusion After Failed Total Ankle Replacement

Proper treatment of failed total ankle replacement remains a challenge. Several revision modalities and techniques exist to either preserve or salvage the ankle joint. Among them there is revision total ankle replacement, amputation, or ankle arthrodesis. The goal of salvage ankle fusion is to restore height and alignment of the hindfoot and to get a stable but pain-free plantigrade and functional foot. Loss of bone and additional deformities pose specific problems for the surgeon and must be taken into consideration during preoperative planning. Meticulous preparation of the fusion sites is crucial to achieve later union of the bones. Although screw fixation alone could be used to get solid fusion, anterior double plating offers an intriguing alternative and provides great stability and high-compressive forces across the fusion site.