Crutches Research Articles

Injuries Associated with Crutch Use: A Narrative Review.

Crutches are commonly prescribed in physiatric settings to help offload the lower extremities. Crutch use, however, results in abnormal and repetitive weight-bearing through the upper extremities that may result in secondary injury. This narrative review investigates injury types and risk factors associated with crutch use in order to guide healthcare providers on injury prevention strategies. Medline, EMBASE, CINAHL, and the Cochrane Library were systematically reviewed for publications between 1950 and 2018 on neurological, musculoskeletal, or vascular complications associated with crutch use. Titles and abstracts (n = 2395) were screened by two authors. Sixty studies were eligible. Articles were reviewed for level of evidence, crutch type, participant characteristics, and injury characteristics. There were 42 axillary crutch studies, 12 forearm crutch studies, and 6 studies that did not specify crutch type. These studies incorporated 622 individuals, and most were case series or case reports (n = 54). Axillary crutch use was most commonly associated with axillobrachial arterial complications due to pressure from the axillary bar (n = 34). Forearm crutch use was most commonly associated with compressive neuropathies due to pressure from the forearm cuff (n = 6). Improper crutch fitting and/or use were identified as contributing factors to injury in 22 cases. Duration of crutch use and medical comorbidities also influenced the types of injuries seen. There are rare but potentially serious complications associated with crutch use. When prescribing crutches, clinicians should ensure they are properly fit, engage in appropriate gait training, be aware of common crutch-related injuries, and consider potential patient-specific injury risk factors in order to minimize injury risk.

Exoskeleton Assistance Improves Crouch during Overground Walking with Forearm Crutches: A Case Study.

Research, development and testing of wearable robotic exoskeletons for gait training and improved mobility in children with cerebral palsy (CP) and other movement disorders has become increasingly prevalent in recent years. Broadly, these devices are split into two categories: fully wearable devices that are affixed to the lower limbs and/or pelvis and systems that include a mobile frame that moves with the user. The former systems have generally targeted more functional individuals who are independent walkers while the latter target more affected individuals who do not ambulate on their own. The best strategy for children in the middle of this mobility spectrum (GMFCS III), who can walk short distances using assistive instruments like crutches or walkers, is not clear. Yet, these children may benefit most from gait training because they are at the highest risk to lose their independent mobility. Here, we present a case study of a wearable robotic exoskeleton for overground walking in a child with CP at GMFCS III. Our results demonstrate that the exoskeleton was able to synchronize assistance to five discrete phases of the gait cycle during overground walking with forearm crutches. Peak knee extension improved on average by 10 degrees in the right leg and 7 degrees in the left leg when walking with exoskeleton assistance during early stance, mid-stance and late swing without reduction in muscle activity. Therefore, state-based control for providing robotic extension assistance to individuals with crouch from CP who walk with assistive instruments should be further investigated as a potential rehabilitation strategy.

Pain mapping and health-related conditions in relation to forearm crutch usage: A cross-sectional study

ABSTRACT To explore pain complaints and health-related conditions, verifying if permanent or temporary usage of forearm crutches could be associated with them. We designed a cross-sectional study from a sample who answered a five-month public call. We organized data into five domains: (1) diseases, signs and symptoms; (2) personal factors related to age, sex, marital status, and paid occupation; (3) body structure and functional components defined by body mass index, arterial pressure, mental state, and pain; (4) activities and participation assessed by satisfaction with Assistive Technology; (5) and environmental factors focused on medicines and forearm crutch usage. The sample was geo-referenced by address, and the frequency of the codified health conditions was distributed according to ICD-10’s chapters. We recruited three times more permanent than temporary users dealing with chronic and external causes of diseases. Pain mapping suggested different pattern of complaints between permanent and temporary users. Women who were temporary users seemed more likely to be injured because of external causes. Moreover, both users reported intense (31%) and moderate (53%) levels of pain. In contrast, mild pains were only reported by permanent users (16%), suggesting a distinction between acute and chronic pain according to the kind of forearm crutch usage.

Poor Outcome of Above-Knee Amputation after Septic Failure of Revision Total Knee Arthroplasty.

Persistent periprosthetic infection following total knee arthroplasty is one of the most dreaded complications of orthopaedic surgery. Treatment strategies include arthrodesis of the knee joint, stable fistula, long-lasting antibiotic therapy, or above-knee amputation. The advantage of amputation in comparison to other treatment options is the possible cure of infection, because the source of infection is removed and no foreign material left in situ. The aim of the study is to examine whether a septic amputation of the femur in case of persistent periprosthetic infection at the knee joint leads to the healing of the patient. Moreover, the physical and mental state should be evaluated. All patients with above-knee amputation because of periprosthetic joint infection after primary total knee arthroplasty between 2016 and 2018 were included in this retrospective study. A questionnaire with the clinical scores visual analog scale, modified Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index and 36-Item Short Form Survey has been designed. In addition, all characteristics and perioperative data were documented. Eleven patients were included in the study. One patient died after above-knee amputation; all other patients live with a marked impairment of quality of life but with absence of the infection of the leg. Two out of ten are able to walk regularly with an exoprosthesis with forearm crutches, 50% are in a wheelchair, while 30% are bedridden. Patients with above-knee amputation after persistent periprosthetic infections were free of infection and without signs of inflammation. However, this is associated with worse mobility and high mortality rate.

Surgical management of proximal femoral metastasis: Fixation or hip replacement? A 309 case series

IntroductionThe proximal femur is the most frequent operative site for metastasis, but there is no consensus between internal fixation and hip replacement. The present multicenter retrospective observational study sought: (1) to compare early clinical results between internal fixation and hip replacement for proximal femoral metastasis (PFM), and (2) to assess events affecting survival. HypothesisThe study hypothesis was that internal fixation and hip replacement give comparable clinical results, operative site complications rates and survival. Material and methodsThe series comprised 309 cases, 10 of which were bilateral, in 182 females and 117 males, with a mean age of 67.2±11.5 years and 62.5±13.2 years, respectively. Primaries were mainly breast (118; 38.2%), lung (85; 25.5%) or kidney (40; 12.9%). PFM was revelatory in 114 cases (36.9%). There was visceral involvement in 142 patients (46%), multiple peripheral bone involvement in 212 (68.6%), and spinal involvement in 134 (43.4%). There were 124 pathologic fractures (40%), 51 of which were revelatory. Metastases were cervicocephalic in 135 cases (43.7%), metaphyseal in 166 (53.7%) and both in 8 (2.6%). PFM was osteolytic in 90% of cases, managed by hip replacement in 161 cases and internal fixation in 148 (12 screwed plates, 136 nails). Seventy-seven patients had postoperative radiation therapy. ResultsAfter hip replacement (n=144), walking was normal in 35 cases (24.3%), impaired but unassisted in 53 (36.8%), with 1 forearm crutch in 24 (16.6%), 2 crutches or a frame in 26 (18%), and impossible in 6 (4.1%). After nailing (n=125), results were respectively 38 (30.4%), 47 (37.6%), 15 (12%), 18 (14.4) and 7 (5.6%). Recovery of normal walking capacity did not significantly differ according to technique (p=0.162); nor did pain or function. Recovery of normal walking capacity was better after preventive surgery (p<0.001). Perioperative complications comprised: 10 cases of severe blood loss, 7 pulmonary embolisms, 6 digestive hemorrhages, and 5 lung infections. Secondarily, there were 11 infections (7 after hip replacement, 2 after nailing, 2 after plate fixation), 7 progressive osteolyses and 5 fractures. Complications rates were significantly higher with plate fixation, with no difference between nailing and hip replacement. Survival did not significantly differ between hip replacement (12 months [95% CI: 7–19]), nailing (7 months [95% CI: 6–11]) and plate fixation (16 months [95% CI: 6-not calculable]). ConclusionsClinical results and survival were comparable between hip replacement and nailing, confirming the study hypothesis, in agreement with the literature. Each technique has its indications. Patients with severely impaired walking capacity benefited greatly from surgery. The importance of preventive surgery was highlighted. Level of evidenceIV, retrospective study.

Comparison of different optimal control formulations for generating dynamically consistent crutch walking simulations using a torque-driven model

Walking impairment due to spinal cord injury can be improved using active orthoses, together with some type of external support such as crutches for balance. This study explores how optimal control problem formulation affects the ability to generate dynamically consistent crutch walking simulations with active orthosis assistance that closely reproduce experimental data. The investigation compares eight optimal tracking problem formulations using a torque-driven full-body skeletal model of a healthy subject walking with active knee-ankle-foot orthoses and forearm crutches. We have found that small adjustments to ground reactions are required to achieve convergence, tracking of joint instead of marker coordinates significantly improves convergence, and minimising joint jerks instead of joint accelerations has only a minor effect on the problem convergence. These results provide guidance for future work that seeks to develop predictive optimal control simulations that can identify orthosis control parameters that maximise improvement in walking function on an individual patient basis.

Estimating upper extremity joint loads of persons with spinal cord injury walking with a lower extremity powered exoskeleton and forearm crutches

Lower extremity powered exoskeletons with crutch support can provide upright mobility to persons with complete spinal cord injury (SCI); however, crutch use for balance and weight transfer may increase upper extremity (UE) joint loads and injury risk. This research presented the first exoskeleton-human musculoskeletal model to estimate upper extremity biomechanics, driven by 3D motion data of persons with complete SCI walking with an exoskeleton and crutch assistance. Forearm crutches instrumented with strain gauges, force plates, and a 3D motion capture system were used to collect kinematic and kinetic data from five persons with complete SCI while walking with the ARKE exoskeleton. Model output estimated participant upper extremity kinematics, kinetics, and crutch forces. Compared to inverse dynamic biomechanical crutch model studies of persons with incomplete SCI, exoskeleton users walked with more anterior trunk tilt and twice the shoulder flexion angle. Anterior tilt increased forces and moments at the crutch, shoulder, and elbow. Crutch floor contact periods were 30–40% longer, resulting in upper extremity joint impulses 5 to 12 times greater than previously reported. Reducing UE joint loading is important to reduce overuse injuries associated with ambulatory assistive devices. Incorporating a variable assist ankle joint or more experience with exoskeleton walking may reduce UE joint loads, and minimise injury risk. Study outcomes provide a quantitative understanding of UE dynamics during exoskeleton walking that can be used to improve device design, training, and rehabilitation.

Eletronic Instrumentation in Lofstrand: Dynamic Force and Attitude Monitoring

This work provides quantitative data related to the use of Lofstrand crutches, these data are the strength applied on the armrest to the contact surface, the angle of the crutch relative to its axis of origin.Modular sensors of magnetometer, gyroscope and accelerometer were used. The results presented are: the dynamic force variation in the order of 0 kgf to 50 kgf was measured by the Force Sensing Resistor (FSR) sensor indicating the convergence of the data with the theoretical reference. Another innovative contribution of this work is the geoprocessing during the walk of the user. Finally, the purpose of the system is to explore the use of the Canadian crutch for the walking response and consequent storage of the users data, providing a mapping for user walk.

Prospective cohort study of the effects of motor cognitive risk syndrome on fractures after falls

Objective To investigate the risk factors of elderly, sports cognitive risk syndrome falling, repeated falls and fractures after falls. Methods A total of 3 552 people were enrolled in the Department of Neurology, the First Affiliated Hospital of China Medical University from April 2015 to April 2016. The demographics of each selected individual were recorded. The selected individuals were assessed by MMSE for the presence of Subjective Cognitive Complaint (SCC), and the pace was used to assess whether there was slow walking and whether there was MCR (SCC + slow walking). All individuals were divided into MCR group and non-MCR group according to the evaluation results. The non-MCR group was subdivided into SCC subgroup, slow speed walking subgroup and healthy subgroup. Baseline variables were compared between the two groups, and demographics between subgroups, subgroups, and MCR groups were compared. Follow-up was followed every 4 months for a total of 2 years. The number of people who fell during the follow-up period, repeated falls, and fractures were recorded. With all demographics and SCC, walking at a slower pace, MCR was an independent variable, with a fall during follow-up, repeated falls and post-fall fractures as dependent variables, and a COX proportional hazard regression model of independent and dependent variables. Results The proportions of the MCR group in higher education, depression, the use of crutches were 10.2% (36/352), 22.4% (79/352), 44.9% (158/352), the BMI, number of medications in the MCR group were (27.0 ± 4.3) kg/m2, (6.8±3.2), the proportions of non-MCR group in higher education, depression, using crutches ratio were 22.9% (732/3 200), 12.8% (409/3 200), 22.8% (729 /3 200), the BMI, number of medications of non-MCR group were (24.8 ± 3.8) kg/m2, (5.2 ± 3.1), the two groups showed statistical significant difference(χ2 values were 29.93, 3.45, 24.98, t values were 12.34, 82.71, P<0.05). The proportions of higher education, depression and crutches were 18.9% (289/1531), 13.2% (202 /1531) and 22.5% (344/1531) in SCC subgroup. The difference between MCR group and SCC subgroup was statistically significant (χ2 values were 14.99, 19.28, 73.56, P<0.05). The higher education level of the slow walking group was 16.6% (34/205), which was significantly different from that of the MCR group (χ2 value was 4.77, P<0.05). The proportions of higher education level, arthritis, depression and crutches in the healthy subgroup were 27.9% (409/1 464), 12.9 (190/1 464), 11.2% (164/1 464) and 19.7% (288/1 464), while that in the SCC subgroup were 18.9% (289/1 531), 16.2 (248/1 531), 13.2% (202/1 531) and 22.5% (344/1 531), and that in the slow walking subgroup were 16.6% (34/205), 21.5% (44/205), 20.9 (43/205) and 47.3% (97/205). There were significant differences among the three subgroups (χ2 values were 13.08-78.28, P<0.05). BMI and number of drugs in healthy subgroups were (23.4±4.4) kg/m2 and (4.7±2.8) , SCC group was (25.2±4.3) kg/m2 and (5.1±2.9) kinds, and slow walking subgroup were (25.1±3.8) kg/m2 and (6.7±3.1) kinds. The differences among the three subgroups were statistically significant (t values were 2.68,7.21, P<0.05). The risks of falling, repeated falling and fracture after falling in MCR patients were 1.22, 1.47 and 2.54 (P<0.05). Conclusions Age, MCR is a high risk factor for falls in the elderly, repeated falls and fractures after falls. In clinical care, MCR needs to be evaluated and attention should be payed to the elderly. Key words: Cognitive impairment; Fall; Post-fall fracture; Cohort study; Elderly

Online Gait Planning of Lower-Limb Exoskeleton Robot for Paraplegic Rehabilitation Considering Weight Transfer Process

People who suffer from paraplegia completely lose sensory and locomotor functions; there are no known treatment methods for their recovery at this time. Exoskeleton robots have the potential to dramatically improve the locomotor ability of these individuals. Although some exoskeleton robots for paraplegic patients have been commercialized and are able to restore walking motion at present, the pilot must acquire the ability to maintain their balance and shift their weight using forearm crutches, which is very challenging for paraplegics. To make this easier, we propose a new automated intelligent gait planning method that integrates a finite-state machine (FSM) model as an underlying foundation and a gait generation model in addition to the exoskeleton system. The underlying FSM model is defined using an inverted pendulum model and a minimum jerk algorithm. To compare the planning gait, 33 volunteers provide normal walking gaits; there are two more volunteers (paraplegic and nonparaplegic) wearing the Shenzhen Institute of Advanced Technology (SIAT) exoskeleton robot to validate the effects of the proposed gait and offer the groups of surface electromyogram (sEMG) data for analysis. As a result, the input of the proposed gait planning method is simplified to two parameters. The proposed walking gait significantly reduces the arm muscle output. Note to Practitioners-This article was motivated by the problem that the four-degree of freedom (DoF) underactuated paraplegic rehabilitation lower limb exoskeleton robot lacks of the center of gravity (COG) transfer process when coordinating with paraplegia patients during the training process for beginner. The existing approach to deal with this problem generally is to train the pilot for obtaining the COG transfer ability by using crutches. This article suggests a gait planning method for the four-DOF underactuated rehabilitation lower limb exoskeleton robot considering the COG transfer process to make the exoskeleton robot coordinate with a pilot and ensure safety. The gait planning method is based on the inverted pendulum model and simplified to several parameters. By adjusting these parameters, the step length, step height, walking speed, and the shape of gait can be adjusted according to the requirements of the exoskeleton robot and pilot. In this article, we mathematically characterize a gait planning method for the exoskeleton control strategy. Preliminary online experiments suggest that this approach is feasible and can significantly reduce the arm muscle output of pilot. In future research, we will adjust the gait by estimating the velocity of center of mass (COM) of the pilot to make the exoskeleton robot coordinate with pilot actively.

Improvement and analysis of a mechanically adapted Lofstrand Crutch model through bond graph modelling

Lofstrand Crutches represent a mobility device applied temporarily during the rehabilitation process or permanently as an assistive device. As a permanent device, they have a deep impact on the body due to the reactive force redistributed on the upper limbs. We present a review on the development and implementation of an innovative cushioning crutch-mounting device as well as a sensorial system for gathering feedback data. Following, we propose a bond graph mathematical model to compare the traditional Lofstrand Crutches (LC) with modified LC (mLC). Through state-space equations extracted from our model, we demonstrate a reduction in the resulting force through the introduction of the damping device on the crutch system. The simulation by the mathematical models demonstrated that the cushioning might incur effective minimisations on the upper limbs force redistribution, avoiding further movement disabilities for permanent users.

Improvement and analysis of a mechanically adapted Lofstrand Crutch model through bond graph modelling

Improvement and analysis of a mechanically adapted Lofstrand Crutch model through bond graph modelling

Análise ergonômica dos dispositivos auxiliares de marcha de uma idosa

Os idosos têm sofrido cada vez mais mudanças no desempenho das habilidades motoras, associadas ao cotidiano ativo e as mudanças degenerativas. Este estudo de caso tem por objetivo desenvolver uma análise ergonômica dos dispositivos auxiliares durante o processo de marcha de uma idosa. Os dois dispositivos auxiliares analisados cumpriram sua função prática, contudo, como o objetivo da idosa é a descarga de peso, concluiu-se que a muleta Lofstrand foi o melhor dispositivo para uso.

May I Keep an Eye on Your Training? Gait Assessment Assisted by a Mobile Robot.

A successful rehabilitation after surgery in hip endoprosthetics comprises self-training of the lessons taught by physiotherapists. While doing this, immediate feedback to the patient about deviations from physiological gait patterns during training is important. Such immediate feedback also concerns the correct usage of forearm crutches in three-point gait. In the project ROGER, a mobile Socially Assistive Robot (SAR) to support patients after surgery in hip endoprosthetics is going to be developed. The current implementation status of the robotic application developed for the use in a real-world scenario is presented below.

Erweiterter medialer und erweiterter lateraler Zugang bei Tibiakopffrakturen

Complete visualization of the articular surface in comminuted uni- or bicondylar tibial plateau fractures as aprerequisite for anatomical reconstruction to reduce the risk of posttraumatic osteoarthritis. Unicondylar lateral or medial as well as bicondylar intra-articular tibial plateau fractures with central and/or dorsal fracture lines; comminuted destruction of the medial or lateral tibial plateau with dislocation of >2 mm. Critical soft tissue in the approach area, femoral condylar fracture, intraligamentous ruptures of the medial or lateral ligaments or the posterolateral corner. Medial: via the medial or anteromedial approach; lateral: via the antero- or posterolateral approach for open reduction and internal fixation of the tibial plateau fracture. Sharp dissection down to the medial/lateral ligamentous accompanying structures with subsequent presentation of the medial/lateral femoral epicondyle. Medial: approximately 2 × 2 cm osteotomy of the medial femoral epicondyle. Lateral: osteotomy of an approximately 1 × 1 × 0.5 cm bone block of the lateral femoral epicondyle either with protection or including the popliteus tendon running ventrally in the sulcus popliteus. In this case, aviolation of the articular condyle should be avoided. Early functional posttreatment with full mobilization and 10-20 kg partial load bearing on forearm crutches, fracture-dependent for 6-12weeks. Very good visualization of the comminuted articular surface with postoperatively anatomical reconstruction of complex fracture patterns without postoperative concomitant instabilities.

Different walk aids on gait parameters and kinematic analysis of the pelvis in patients with Adult Neuromuscular Disease.

Objectives:To investigate the effects of different walking aids (single cane, bilateral forearm crutch and walker) on gait parameters and kinematic analysis of pelvis in patients having adult neuromuscular diseases.Methods:The study design was a self-controlled study. The study was conducted in the Department of Physiotherapy and Rehabilitation, Hacettepe University in Ankara, Turkey, between 2014-2015. The study included 18 adult patients with neuromuscular disease. The manual muscle test, the Rivermead mobility index, the motor function assessment scale, and the trunk control test were used as descriptive measurements. The 2-minute walking test, the modified Borg scale and the G-Walk gait analysis system (BTS Bioenginering S.p.A., Italy) were used as the outcome measures. The outcome measures were performed randomly during normal gait without walking aids (self control group), then during walking with single point cane, bilateral forearm crutch and walker.Results:It was observed that the walking aids have decreased the walking speed, walking distance and cadence. When the pelvis kinematic was analyzed, there was only a significant difference in the extension of the pelvis between the groups (p<0.05). The most useful (61%), most comfortable (44.4%) and the most preferred (61%) walking aid was determined as single cane by patients and the safest (55%) one was determined as a walker.Conclusion:Conclusion: In the decision-making process for walking aids, the patient’s biomechanical, physiological and psychosocial needs, expectations, satisfactions and levels of independence should be considered before providing patients with aids for walking.

Ilizarov technique in combination with bone grafting and ankle traction for treatment of periarticular nonunion at the distal tibia

Objective To evaluate the clinical efficacy of a combination of Ilizarov technique, bone grafting and ankle traction for treatment of nonunion of the distal tibia within 2 cm around the ankle joint. Methods A retrospective study was performed on the patients who had been treated at Department of Orthopaedics, Sir Run Run Shaw Hospital from September 2014 to January 2018 for nonunion of the distal tibia within 2 cm around the ankle joint. They were 8 men and 4 women, aged from 32 to 56 years (average, 41 years). Their injury was all unilateral, involving 5 left and 7 right ankles. They had all received internal fixation at other hospitals for 6 to 18 months. After we treated them simultaneously with Ilizarov technique, bone grafting and ankle traction, they could walk with crutches as soon as 3 days after surgery in some cases. Their affected limbs were then subjected to gradual weight-bearing walking until they could walk normally without any aid 3 to 6 months after surgery. Their postoperative ankle functions were evaluated according to the ankle-hindfoot scores of the American Orthopedic Foot and Ankle Society (AOFAS) system. Results The 12 patients were effectively followed up for 12 to 24 months (average, 19 months). All their incisions healed well with no incision or pin-tract infection. All their bone nonunions healed after circular external fixation for 12 to 36 weeks. Their AOFAS scores ranged from 75 to 96 points, showing good functional recovery of the ankle joint. Conclusion A combination of Ilizarov technique, bone grafting and ankle traction is an effective treatment for nonunion of the distal tibia within 2 cm around the ankle joint, leading to preservation of the ankle function and prevention of posttraumatic ankle osteoarthritis. Key words: Fractures, ununited; Bone grafting; Osteoarthritis; Ilizarov technique; Ankle traction

Hemiarthroplasty with Wagner SL prosthesis for failed internal fixation of intertrochanteric fractures in elderly patients

Objective To investigate the clinical outcomes of hemiarthroplasty with Wagner SL prosthesis in treating failed internal fixation of intertrochanteric fractures of elderly patients. Methods A retrospective case series study was conducted on the clinical data of 14 patients with failed internal fixation of intertrochanteric fractures admitted between March 2015 to April 2018. There were seven males and seven females with a mean age of 82.2 years (range, 75-94 years). The primary internal fixators were proximal femoral nail anti rotation in nine patients, dynamic hip screw in three patients, and proximal femoral locking plate in two patients. The main causes of internal fixation failure were screw loosening in six patients, cutting out of screws in five patients, nonunion in two patients, and plate breakage with nonunion in one patient. Affected limb shortening and coxa varus deformity to various degrees were seen in all the patients before operation. The mean interval from internal fixation to hemiarthroplasty was 6.6 months (range, 2-12 months). All patients received hemiarthroplasty using Wagner SL prosthesis, of which nine patients had additional trochanter claw plate with titanium cable fixation and two patients had tension band wire fixation. The operation time, intraoperative, and postoperative complications were recorded. Harris hip scores were measured before operation and at the last follow up to evaluate hip function. Radiographs were performed to assess the fracture healing, prosthesis position, and biological fixation. Results All patients were followed up for 6-30 months (mean, 14.5 months). The mean operation time was (108.0±12.4)minutes (range, 88-130 minutes). No iatrogenic fracture occurred during the operation. One patient was seen contralateral intertrochanteric fracture during follow-up, and no complications such as periprosthetic fracture, prosthetic sinking, and infection occurred in the 13 patients. The Harris score increased from (26.1±7.5)points before operation to (83.1±4.1)points after operation (P<0.01). All patients were able to stand and walk, of which four needed crutch assistance. At the last follow-up, X-ray film showed that the prosthesis was well positioned and that all of them reached bony fixation. Fourteen cases of greater trochanteric fracture were healed, with two cases of slight displacement. Conclusions Hemiarthroplasty is an effective remedial treatment for failed internal fixation of intertrochanteric fractures in the elderly, which can improve hip function and enhance the life quality of patients. Wagner SL prosthesis can obtain stable fixation. Key words: Arthroplasty, replacement, hip; Hip fractures; Treatment failure

Influence of the load exerted over a forearm crutch in spatiotemporal step parameters during assisted gait: pilot study

BackgroundAssisted gait with forearm crutches is frequently performed during the recovery of musculoskeletal injuries of the lower limb. The amount of body weight applied to the crutch or crutches depends on the pathology and the treatment phase. The transition from assisted gait with two crutches to a single crutch is usually recommended when the subject is able to load the 50% of the body weight upon the affected member. An altered assisted gait will cause biomechanic alterations and, therefore, longer treatments and relapses. The aim of this study was to analyze the influence of 10, 25 and 50% of body weight applied to a forearm crutch during a unilateral assisted gait in the spatial and temporal step parameters to determine the load that produces alterations in gait biomechanics and the load that does not.MethodsEleven healthy subjects performed normal gait (NG) and assisted gait with a forearm crutch, in which the applied loads were: comfortable (C), 25 and 50% of their body weight. Vicon System was employed for gait recording. GCH System 2.0 and GCH Control Software 1.0 controlled the loads. The variables were: step length, step period, velocity, step width and step angle. Friedman test compared all the gait modalities: NG and the different loads. Wilcoxon signed-rank test analyzed ipsilateral and contralateral step parameters to the crutch globally and for each subject.ResultsFriedman test showed significant differences between NG, C, 25 and 50%, especially for step period and velocity. Wilcoxon test had significant differences only in 4 of the 20 general comparisons between ipsilateral and contralateral steps to the crutch. In the analysis by subjects, step length, step period and velocity showed 79/132, 110/132 and 58/66 significant differences, respectively.ConclusionsThe increase in the load exerted over a forearm crutch produced an increase in the step period, accompanied by a reduction of step length and gait velocity. Step width and step angle were not modified. The unloading of 25 and 50% of body weight on a single crutch is incorrect from the biomechanical point of view. Two crutches should be employed when the body weight to unload exceeds 10%.

Modeling and Simulation of a Lower Extremity Powered Exoskeleton.

Lower extremity powered exoskeletons (LEPEs) allow people with spinal cord injury (SCI) to stand and walk. However, the majority of LEPEs walk slowly and users can become fatigued from overuse of forearm crutches, suggesting LEPE design can be enhanced. Virtual prototyping is a cost-effective way of improving design; therefore, this research developed and validated two models that simulate walking with the Bionik Laboratories' ARKE exoskeleton attached to a human musculoskeletal model. The first model was driven by kinematic data from 30 able-bodied participants walking at realistic slow walking speeds (0.2-0.8 m/s) and accurately predicted ground reaction forces (GRF) for all speeds. The second model added upper limb crutches and was driven by 3-D-marker data from five SCI participants walking with ARKE. Vertical GRF had the strongest correlations (>0.90) and root-mean-square error (RMSE) and mediolateral center of pressure trajectory had the weakest (<0.35), for both models. Strong correlations and small RMSE between predicted and measured GRFs support the use of these models for optimizing LEPE joint mechanics and improving LEPE design.