Pressure, oxygen tension and temperature in the periosteal callus during bone healing - An in vivo study in sheep

Adequate blood supply and sufficient mechanical stability are necessary for timely fracture healing. Damage to vessels impairs blood supply; hindering the transport of oxygen which is an essential metabolite for cells involved in repair. The degree of mechanical stability determines the mechanical conditions in the healing tissues. The mechanical conditions can influence tissue differentiation and may also inhibit revascularization. Knowledge of the actual conditions in a healing fracture in vivo is extremely limited. This study aimed to quantify the pressure, oxygen tension and temperature in the external callus during the early phase of bone healing. Six Merino-mix sheep underwent a tibial osteotomy. The tibia was stabilized with a standard mono-lateral external fixator. A multi-parameter catheter was placed adjacent to the osteotomy gap on the medial aspect of the tibia. Measurements of oxygen tension and temperature were performed for ten days post-op. Measurements of pressure were performed during gait on days three and seven. The ground reaction force and the interfragmentary movements were measured simultaneously. The maximum pressure during gait increased (p=0.028) from three (41.3 [29.2-44.1] mm Hg) to seven days (71.8 [61.8-84.8] mm Hg). During the same interval, there was no change (p=0.92) in the peak ground reaction force or in the interfragmentary movement (compression: p=0.59 and axial rotation: p=0.11). Oxygen tension in the haematoma (74.1 mm Hg [68.6-78.5]) was initially high post-op and decreased steadily over the first five days. The temperature increased over the first four days before reaching a plateau at approximately 38.5 degrees C on day four. This study is the first to report pressure, oxygen tension and temperature in the early callus tissues. The magnitude of pressure increased even though weight bearing and IFM remained unchanged. Oxygen tensions were initially high in the haematoma and fell gradually with a low oxygen environment first established after four to five days. This study illustrates that in bone healing the local environment for cells may not be considered constant with regard to oxygen tension, pressure and temperature.

Plantar fasciitis : are pain and fascial thickness associated with arch shape and loading?

Background and Purpose Although plantar fascial thickening is a sonographic criterion for the diagnosis of plantar fasciitis, the effect of local loading and structural factors on fascial morphology are unknown. The purposes of this study were to compare sonographic measures of fascial thickness and radiographic measures of arch shape and regional loading of the foot during gait in individuals with and without unilateral plantar fasciitis and to investigate potential relationships between these loading and structural factors and the morphology of the plantar fascia in individuals with and without heel pain. Subjects The participants were 10 subjects with unilateral plantar fasciitis and 10 matched asymptomatic controls. Methods Heel pain on weight bearing was measured by a visual analog scale. Fascial thickness and static arch angle were determined from bilateral sagittal sonograms and weight-bearing lateral foot roentgenograms. Regional plantar loading was estimated from a pressure plate. Results On average, the plantar fascia of the symptomatic limb was thicker than the plantar fascia of the asymptomatic limb (6.1±1.4 mm versus 4.2±0.5 mm), which, in turn, was thicker than the fascia of the matched control limbs (3.4±0.5 mm and 3.5±0.6 mm). Pain was correlated with fascial thickness, arch angle, and midfoot loading in the symptomatic foot. Fascial thickness, in turn, was positively correlated with arch angle in symptomatic and asymptomatic feet and with peak regional loading of the midfoot in the symptomatic limb. Discussion and Conclusion The findings indicate that fascial thickness and pain in plantar fasciitis are associated with the regional loading and static shape of the arch.

Fitness and fatness in childhood obesity : implications of physical activity

Overweight and obesity are a significant cause of poor health worldwide, particularly in conjunction with low levels of physical activity (PA). PA is health-protective and essential for the physical growth and development of children, promoting physical and psychological health while simultaneously increasing the probability of remaining active as an adult. However, many obese children and adolescents have a unique set of physiological, biomechanical, and neuromuscular barriers to PA that they must overcome. It is essential to understand the influence of these barriers on an obese child's motivation in order to exercise and tailor exercise programs to the special needs of this population. Chapter Outline • Introduction • Defining Physical Activity, Exercise, and Physical Fitness • Physical Activity, Physical Fitness, And Motor Competence In Obese Children • Physical Activity and Obesity in Children • Physical Fitness in Obese Children • Balance and Gait in Obese Children • Motor Competence in Obese Children • Physical Activity Guidelines for Obese Children • Clinical Assessment of the Obese Child • Physical Activity Characteristics: Mode • Physical Activity Characteristics: Intensity • Physical Activity Characteristics: Frequency • Physical Activity Characteristics: Duration • Conclusion

Categorisation of activities of daily living of lower limb amputees during short-term use of a portable kinetic recording system : a preliminary study

The purpose of this preliminary study was to determine the relevance of the categorization of the load regime data to assess the functional output and usage of the prosthesis of lower limb amputees. The objectives were a) to introduce a categorization of load regime, b) to present some descriptors of each activity, and c) to report the results for a case. The load applied on the osseointegrated fixation of one transfemoral amputee was recorded using a portable kinetic system for 5 hours. The periods of directional locomotion, localized locomotion, and stationary loading occurred 44%, 34%, and 22% of recording time and each accounted for 51%, 38%, and 12% of the duration of the periods of activity, respectively. The absolute maximum force during directional locomotion, localized locomotion, and stationary loading was 19%, 15%, and 8% of the body weight on the anteroposterior axis, 20%, 19%, and 12% on the mediolateral axis, and 121%, 106%, and 99% on the long axis. A total of 2,783 gait cycles were recorded. Approximately 10% more gait cycles and 50% more of the total impulse than conventional analyses were identified. The proposed categorization and apparatus have the potential to complement conventional instruments, particularly for difficult cases.

Falls in Parkinson’s disease : evidence for altered stepping strategies on compliant surfaces

Background: Real-world environments comprise surfaces of different textures, densities and gradients, which can threaten postural stability and increase falls risk. However, there has been limited research that has examined how walking on compliant surfaces influences gait and postural stability in older people and PD patients. Methods: PD patients (n = 49) and age-matched controls (n = 32) were assessed using three dimensional motion analysis during self-paced walking on both firm and foam walkways. Falls were recorded prospectively over 12 months using daily falls calendars. Results: Walking on a foam surface influenced the temporospatial characteristics for all groups, but PD fallers adopted very different joint kinematics compared with controls. PD fallers also demonstrated reduced toe clearance and had increased mediolateral head motion(relative to walking velocity) compared with control participants. Conclusions: Postural control deficits in PD fallers may impair their capacity to attenuate surface-related perturbations and control head motion. The risk of falling for PD patients may be increased on less stable surfaces.

The reliability, accuracy and minimal detectable difference of a multi-segment kinematic model of the foot-shoe complex

Kinematic models are commonly used to quantify foot and ankle kinematics, yet no marker sets or models have been proven reliable or accurate when wearing shoes. Further, the minimal detectable difference of a developed model is often not reported. We present a kinematic model that is reliable, accurate and sensitive to describe the kinematics of the foot–shoe complex and lower leg during walking gait. In order to achieve this, a new marker set was established, consisting of 25 markers applied on the shoe and skin surface, which informed a four segment kinematic model of the foot–shoe complex and lower leg. Three independent experiments were conducted to determine the reliability, accuracy and minimal detectable difference of the marker set and model. Inter-rater reliability of marker placement on the shoe was proven to be good to excellent (ICC = 0.75–0.98) indicating that markers could be applied reliably between raters. Intra-rater reliability was better for the experienced rater (ICC = 0.68–0.99) than the inexperienced rater (ICC = 0.38–0.97). The accuracy of marker placement along each axis was <6.7 mm for all markers studied. Minimal detectable difference (MDD90) thresholds were defined for each joint; tibiocalcaneal joint – MDD90 = 2.17–9.36°, tarsometatarsal joint – MDD90 = 1.03–9.29° and the metatarsophalangeal joint – MDD90 = 1.75–9.12°. These thresholds proposed are specific for the description of shod motion, and can be used in future research designed at comparing between different footwear.

Next generation low-cost motion capture systems can provide comparable spatial accuracy to high-end systems

The objective quantification of three-dimensional kinematics during different functional and occupational tasks is now more in demand than ever. The introduction of new generation of low-cost passive motion capture systems from a number of manufacturers has made this technology accessible for teaching, clinical practice and in small/medium industry. Despite the attractive nature of these systems, their accuracy remains unproved in independent tests. We assessed static linear accuracy, dynamic linear accuracy and compared gait kinematics from a Vicon MX20 system to a Natural Point OptiTrack system. In all experiments data were sampled simultaneously. We identified both systems perform excellently in linear accuracy tests with absolute errors not exceeding 1%. In gait data there was again strong agreement between the two systems in sagittal and coronal plane kinematics. Transverse plane kinematics differed by up to 3 at the knee and hip, which we attributed to the impact of soft tissue artifact accelerations on the data. We suggest that low-cost systems are comparably accurate to their high-end competitors and offer a platform with accuracy acceptable in research for laboratories with a limited budget.

Recommendations for the reporting of foot and ankle models

Multiple marker sets and models are currently available for assessing foot and ankle kinematics in gait. Despite the presence of such a wide variety of models, the reporting of methodological designs remains inconsistent and lacks clearly defined standards. This review highlights the variability found when reporting biomechanical model parameters, methodological design, and model reliability. Further, the review clearly demonstrates the need for a consensus of what methodological considerations to report in manuscripts, which focus on the topic of foot and ankle biomechanics. We propose five minimum reporting standards, that we believe will ensure the transparency of methods and begin to allow the community to move towards standard modelling practice. The strict adherence to these standards should ultimately improve the interpretation and clinical useability of foot and ankle marker sets and their corresponding models.

Defining standards for modelling the biomechanics of the foot and ankle : a systematic review

The complex interaction of the bones of the foot has been explored in detail in recent years, which has led to the acknowledgement in the biomechanics community that the foot can no longer be considered as a single rigid segment. With the advance of motion analysis technology it has become possible to quantify the biomechanics of simplified units or segments that make up the foot. Advances in technology coupled with reducing hardware prices has resulted in the uptake of more advanced tools available for clinical gait analysis. The increased use of these techniques in clinical practice requires defined standards for modelling and reporting of foot and ankle kinematics. This systematic review aims to provide a critical appraisal of commonly used foot and ankle marker sets designed to assess kinematics and thus provide a theoretical background for the development of modelling standards.

Improving posture and decreasing pain with novel shoe insoles

A single subject longevity study is presented as a case study for the Medical Device Partnering Program (MDPP). The MDPP supports the development of cutting-edge medical devices and assistive technologies, through unique collaborations between researchers, industry, clinical end-users and government. The study aimed to identify what effect the innersole has on specific muscles that may influence stability and whether the innersole had any influence on gait. Three tests were conducted; a standard gait test, dynamic balance test and a standing balance test. Results from the kinematic analysis showed reduced variability in post testing results when compared to pre testing results. Reductions in muscle activation levels were also found across all tests. Further testing with a larger sample size is required to determine if these effects are due to the innersole.

The development of a multi-segment kinematic model of footwear

In gait analysis, both shoe mounted and skin mounted markers have been used to quantify the movement of the foot inside the shoe. However, these models have not been demonstrated as reliable or accurate in shod conditions. The purpose of this study was to develop an accurate and reliable marker set to describe foot-shoe complex kinematics during stance phase.

A Systematic Review of kinematic models used in foot & ankle biomechanics

Over the past decade our understanding of foot function has increased significantly[1,2]. Our understanding of foot and ankle biomechanics appears to be directly correlated to advances in models used to assess and quantify kinematic parameters in gait. These advances in models in turn lead to greater detail in the data. However, we must consider that the level of complexity is determined by the question or task being analysed. This systematic review aims to provide a critical appraisal of commonly used marker sets and foot models to assess foot and ankle kinematics in a wide variety of clinical and research purposes.

Towards an accurate biomechanical model of the ankle

When compared with similar joint arthroplasties, the prognosis of Total Ankle Replacement (TAR) is not satisfactory although it shows promising results post surgery. To date, most models do not provide the full anatomical functionality and biomechanical range of motion of the healthy ankle joint. This has sparked additional research and evaluation of clinical outcomes in order to enhance ankle prosthesis design. However, the limited biomechanical data that exist in literature are based upon two-dimensional, discrete and outdated techniques1 and may be inaccurate. Since accurate force estimations are crucial to prosthesis design, a paper based on a new biomechanical modeling approach, providing three dimensional forces acting on the ankle joint and the surrounding tissues was published recently, but the identified forces were suspected of being under-estimated, while muscles were . The present paper reports an attempt to improve the accuracy of the analysis by means of novel methods for kinematic processing of gait data, provided in release 4.1 of the AnyBody Modeling System (AnyBody Technology, Aalborg, Denmark) Results from the new method are shown and remaining issues are discussed.

Defining standards for modelling the biomechanics of the foot and ankle: A systematic review

The complex interaction of the bones of the foot has been explored in detail in recent years, which has led to the acknowledgement in the biomechanics community that the foot can no longer be considered as a single rigid segment. With the advance of motion analysis technology it has become possible to quantify the biomechanics of simplified units or segments that make up the foot. Advances in technology coupled with reducing hardware prices has resulted in the uptake of more advanced tools available for clinical gait analysis. The increased use of these techniques in clinical practice requires defined standards for modelling and reporting of foot and ankle kinematics. This systematic review aims to provide a critical appraisal of commonly used foot and ankle marker sets designed to assess kinematics and thus provide a theoretical background for the development of modelling standards.

Interacting constraints of defensive pressure and ball displacement trajectories shape locomotor pointing behaviours in association football

Performance of locomotor pointing tasks (goal-directed locomotion) in sport is typically constrained by dynamic factors, such as positioning of opponents and objects for interception. In the team sport of association football, performers have to coordinate their gait with ball displacement when dribbling and when trying to prevent opponent interception when running to kick a ball. This thesis comprises two studies analysing the movement patterns during locomotor pointing of eight experienced youth football players under static and dynamic constraints by manipulating levels of ball displacement (ball stationary or moving) and defensive pressure (defenders absent, or positioned near or far during performance). ANOVA with repeated measures was used to analyse effects of these task constraints on gait parameters during the run-up and cross performance sub-phase. Experiment 1 revealed outcomes consistent with previous research on locomotor pointing. When under defensive pressure, participants performed the run-up more quickly, concurrently modifying footfall placements relative to the ball location over trials. In experiment 2 players coordinated their gait relative to a moving ball significantly differently when under defensive pressure. Despite no specific task instructions being provided beforehand, context dependent constraints interacted to influence footfall placements over trials and running velocity of participants in different conditions. Data suggest that coaches need to manipulate task constraints carefully to facilitate emergent movement behaviours during practice in team games like football.