Biomechanical Theory Research Articles

A new integrated behavioural intervention for knee osteoarthritis: development and pilot study

BackgroundExercise-based approaches have been a cornerstone of physiotherapy management of knee osteoarthritis for many years. However, clinical effects are considered small to modest and the need for continued adherence identified as a barrier to clinical efficacy. While exercise-based approaches focus on muscle strengthening, biomechanical research has identified that people with knee osteoarthritis over activate their muscles during functional tasks. Therefore, we aimed to create a new behavioural intervention, which integrated psychologically informed practice with biofeedback training to reduce muscle overactivity, and which was suitable for delivery by a physiotherapist.MethodsThrough literature review, we created a framework linking theory from pain science with emerging biomechanical concepts related to overactivity of the knee muscles. Using recognised behaviour change theory, we then mapped a set of intervention components which were iteratively developed through ongoing testing and consultation with patients and physiotherapists.ResultsThe underlying framework incorporated ideas related to central sensitisation, motor responses to pain and also focused on the idea that increased knee muscle overactivity could result from postural compensation. Building on these ideas, we created an intervention with five components: making sense of pain, general relaxation, postural deconstruction, responding differently to pain and functional muscle retraining. The intervention incorporated a range of animated instructional videos to communicate concepts related to pain and biomechanical theory and also used EMG biofeedback to facilitate visualization of muscle patterns. User feedback was positive with patients describing the intervention as enabling them to “create a new normal” and to be “in control of their own treatment.” Furthermore, large reductions in pain were observed from 11 patients who received a prototype version of the intervention.ConclusionWe have created a new intervention for knee osteoarthritis, designed to empower individuals with capability and motivation to change muscle activation patterns and beliefs associated with pain. We refer to this intervention as Cognitive Muscular Therapy. Preliminary feedback and clinical indications are positive, motivating future large-scale trials to understand potential efficacy. It is possible that this new approach could bring about improvements in the pain associated with knee osteoarthritis without the need for continued adherence to muscle strengthening programmes.Trial registrationISRCTN51913166 (Registered 24-02-2020, Retrospectively registered).

Parameterized Analysis of Craniocerebral Injury Caused by Fist.

Objective Based on the theory of biomechanics, the finite element method was used to study the injury characteristics of different parts of brain hit by fist with different force and to predict the risk of craniocerebral injury, in order to provide reference for actual medical protection and forensic identification. Methods The finite element model of fist was constructed by using DICOM data modeling method and related software, and the effective mass and speed of fist were used to represent the kinetic energy of fist, and combined with human finite element model THUMS 4.02, the characteristics of craniocerebral injury caused by frontal and lateral blows were parametrically simulated. Results The probability of direct death from a blow to the head was low, but as fist power increased, so did the risk of craniocerebral injury. The characteristics of craniocerebral injury were also significantly different with the different fist hitting head locations. When the frontal area was attacked, the maximum equivalent stress of skull was 122.40 MPa, while that of brain tissue was 4.31 kPa. When the temporal area was attacked, the maximum equivalent stress of skull was 71.53 MPa, while that of brain tissue was 7.09 kPa. Conclusion The characteristics and risks of skull fracture and brain tissue injury are different when different parts of the brain are hit by fist. When the frontal area is hit, the risk of skull fracture is significantly higher than when the temporal area is hit. The risk of brain tissue injury is the opposite. The position with the highest probability of skull fracture is generally the place where the skull is directly impacted, and with the conduction of stress waves, it will spread to other parts of the skull, while the position with the highest risk of brain tissue injury is not the place where the brain is directly impacted.

Mechanobiology and Adaptive Plasticity Theory as a Potential Confounding Factor in Predicting Musculoskeletal Foot Function.

There are many theoretical models that attempt to accurately and consistently link kinematic and kinetic information to musculoskeletal pain and deformity of the foot. Biomechanical theory of the foot lacks a consensual model: clinicians are enticed to draw from numerous paradigms, each having different levels of supportive evidence and contrasting methods of evaluation, in order to engage in clinical deduction and treatment planning. Contriving to find a link between form and function lies at the heart of most of these competing theories and the physical nature of the discipline has prompted an engineering approach. Physics is of great importance in biology and helps us to model the forces that the foot has to deal with in order for it to work effectively. However, the tissues of the body have complex processes that are in place to protect them and they are variable between individuals. Research is uncovering why these differences exist and how these processes are governed. The emerging explanations for adaptability of foot structure and musculoskeletal homeostasis offer new insights into how clinical variation in outcomes and treatment effects might arise. These biological processes underlie how variation in the performance and use of common traits, even within apparently similar subgroups, make anatomical distinction less meaningful and are likely to undermine the justification of a "foot type." Furthermore, mechanobiology introduces a probabilistic element to morphology based on genetic and epigenetic factors.

Interpretation of therapeutic effect of fan-ashi point based on tension transmission of skeletal muscle

Given that the biomechanical theory cannot well explain the therapeutic effect of fan-ashi point (a special site that may relieve pain by pressing), the skeletal muscle tension is adopted and it is attempted to interpret the mechanism of the curative effect and the effect onset of fan-ashi point. It is viewed that the longitudinal tension conduction and transverse tension conduction pathways of skeletal muscle are the material basis of the effect onset of fan-ashi point. Hence, acupuncture at fan-ashi point may alter the longitudinal or transverse tension conduction of skeletal muscle to relieve muscle and tendon pain.

Does plate-screw density affect the functional outcomes in the treatment of proximal humerus fractures?

The aim of the study is to evaluate the relationship between plate-screw density (PSD), functional results, and complication rates in the treatment of proximal humerus fractures (PHFs) with proximal humerus locking anatomical plate (PHLAP). Consecutive 43 patients (22 females and 21 males) who underwent PHLAP for the treatment of PHF between 2010 and 2016 were evaluated. AO classifications were used for the classification of fractures. Based on the biomechanical stability the-ory of Erhardt et al., the patients were divided into two groups as <60% and >60% according to the number of screws fixed to the humeral head for the determination of PSD. The patients were divided into two groups as PSD <60% (n=21) and PSD>60% (n=22) according to the number of screws fixed to the humeral head for the determination of PSD. Functional results were evaluated using the Constant-Murley shoulder score (CMS). Radiological evaluation was performed with collodiaphyseal angle (CDA), varus-valgus angulation, avascular necrosis (AVN), and arthrosis. The groups were compared in terms of demographic characteristics, functional results, radiological scores, and complications. The mean age was 54.47±17.43 years and the mean follow-up time was 19.51±5.27 months. Although the CMS scores of patients with a PSD of over 60% were higher than those below 60%, the CMS score did not differ statistically. In groups, the mean CDA of the operated shoulder was significantly lower than that of the non-injured side (p=0.002). Eight patients had varus angulation, whereas two patients had humerus head AVN. No significant relationship was observed between PDS and functional scores, radiolog-ical results, and complications. Functional results of PSD >60% are higher than PSD <60% group but there is no statistical difference between groups according to functional, radiological results, and complications.

Rapid and longer-term effects of selective breeding for voluntary exercise behavior on skeletal morphology in house mice.

Selection experiments can elucidate the varying course of adaptive changes across generations. We examined the appendicular skeleton of house mice from four replicate High Runner (HR) lines bred for physical activity on wheels and four non-selected Control (C) lines. HR mice reached apparent selection limits between generations 17 and 27, running ~3-fold more than C. Studies at generations 11, 16, and 21 found that HR mice had evolved thicker hindlimb bones, heavier feet, and larger articular surface areas of the knee and hip joint. Based on biomechanical theory, any or all of these evolved differences may be beneficial for endurance running. Here, we studied mice from generation 68, plus a limited sample from generation 58, to test whether the skeleton continued to evolve after selection limits were reached. Contrary to our expectations, we found few differences between HR and C mice for these later generations, and some of the differences in bone dimensions identified in earlier generations were no longer statistically significant. We hypothesize that the loss of apparently coadapted lower-level traits reflects (1) deterioration related to a gradual increase in inbreeding and/or (2) additional adaptive changes that replace the functional benefits of some skeletal changes.

Proximal Fibular Osteotomy: Biomechanics, Indications, Technique, and Results.

The evidence base is growing regarding proximal fibular osteotomy. Most studies show that the pain relief and improvement in terms of radiology is statistically significant. More understandable biomechanical theories explaining this improvement are appearing. Because it has a low complication rate and is relatively easy to execute, proximal fibular osteotomy should definitely be considered in any algorithm for the treatment of medial compartment osteoarthritis of the knee. [Orthopedics. 2020;43(6):e627-e631.].

Propulsive forces on water polo players’ feet from eggbeater kicking estimated by pressure distribution analysis

ABSTRACT The purpose of this study was to characterise the unsteady propulsive force during eggbeater kicking by a fluid force estimation method based on pressure distribution analysis. The eggbeater kick was performed by six male water polo players. The participants’ eggbeater kicking motions were recorded by three cameras, and the kinematic foot variables were analysed. The pressure distributions around the foot were measured by four pairs of pressure sensors attached to the dorsal and plantar surfaces of the participants’ right foot. The resultant fluid force acting on the foot was estimated from the measured pressure and area of the foot. The calculated propulsive force increased with the pressure difference between the plantar and dorsal sides of the foot, which was mainly related to the decrease in pressure on the dorsal side, and peaked when the foot passed its maximum velocity and began to decelerate. These results cannot be elucidated only by conventional biomechanical theories of swimming propulsion (Newton’s laws of motion and the quasi-steady approach) but instead indicate a high possibility that the exerted propulsive force is induced by the effects of unsteady water flow.

A Modeling Method of Human Knee Joint Based on Biomechanics

In order to establish an accurate model of human knee joint, which lays a foundation for the follow-up finite element analysis of knee joint and biomechanics analysis, the paper based on the theory of biomechanics and MRI, with the help of professional modeling software, provides a 3D geometric model modeling and materialization processing method of knee joint, and established a total knee joint model including femur, tibia, fibular, meniscus, cartilage, ligament and other related structures.

How does dental implant shape, diameter, length impact its success rate? – A review of literature

Dental implants have greatly evolved over the past 20 years. Understanding and using biomechanical theories that affect endosseous implant design may improve the success of these implants in various load conditions and may allow the clinician to better apply these guidelines, with an improvement in success rates. This review attempts to integrate information available in the dental literature and address current controversies and issues in selecting the diameter, length, and shapes of dental implants.

Local orthodontic force initiates widespread remodelling of the maxillary alveolar bone

Abstract Objectives To clarify the effects of a local orthodontic force on alveolar bone by analysing bone remodelling in different regions of the maxilla during orthodontic tooth movement (OTM). Methods An OTM model was established in rats. Histological changes in the maxilla were analysed using TRAP staining, IHC staining for CTSK and haematoxylin and eosin (H and E) staining. The root bifurcation region of the alveolar bone of the first (M1), second (M2) and third (M3) molars were selected as the regions of interest (ROIs), which were further divided into a cervical and an apical level. Sequential fluorochrome labelling was performed to analyse bone deposition rates. Results The maxillary left first molars were moved mesially. TRAP staining and IHC staining for CTSK showed orthodontic force increased osteoclast numbers in all six ROIs at both the cervical and apical levels. H and E staining indicated elevated osteoblast numbers in the OTM group in all induced regions. Sequential fluorochrome labelling exhibited increased bone deposition rates around M1, M2 and M3 in the OTM group. Conclusions An orthodontic force applied to the first molar could initiate widespread remodelling of the maxillary alveolar bone, which was not restricted to the tension and pressure sites. This may revise the orthodontic biomechanical theory and provide new insights for clinical work.

Lightweight Splint Design for Individualized Treatment of Distal Radius Fracture.

A systematic design approach is proposed for medical splints for individualized treatment of the distal radius fracture. An initial split structural model is first constructed by 3D scanning of an injured limb. Based on the biomechanical theory and clinical experiences, the topology optimization method is applied to design the splint structure. The optimized lightweight splint is realized by additive manufacturing using polylactic acid. Compared to the traditional designs for the distal radius fracture, the optimized design by the proposed approach exhibits a weight reduction of more than 40%. Besides, the mechanical properties of the splint meet the requirements of medical treatment according to the simulation results. Numerical examples are provided to demonstrate the applicability of the approach.

The coach–scientist relationship in high-performance sport: Biomechanics and sprint coaches

It is common for sport science practitioners, including sport biomechanists, to interact with high-performance coaches in the daily training environment. These relationships are beneficial for both scientist and coach, as well as the athletes. However, as indicated by difficulties in transferring new research into coaching practice, these relationships are not functioning as well as they could. The aim of this paper is to examine the various factors that influence the coach–biomechanist relationship in the elite sprinting context and gain an understanding of what impedes and enhances this, which will ultimately maximise an athlete's performance. Sprint coaches ( n = 56) and applied sport biomechanists ( n = 12) were surveyed to determine the participants' experiences working with each other and use of biomechanics in the training environment. Semi-structured interviews with coaches ( n = 8) and biomechanists ( n = 8) were conducted to further explore these ideas. From the biomechanists perspective, the relationship appeared to be less effective than from the coaches' perspective and both groups identified areas for improvement. The coaches had an inconsistent understanding of biomechanics theory and the support a biomechanist could provide in the training environment, while it was acknowledged that biomechanists needed to improve their communication skills. Coach and practitioner education were identified as where these improvements could be facilitated. There are many aspects of the coach–biomechanist relationship that could contribute to establishing optimal practice in the high-performance environment and enhance the transfer of knowledge from scientist to coach. This paper proposes a number of directions that could be taken.

Age-Dependent Variation of Lamina Cribrosa Displacement During the Standardized Valsalva Maneuver

Based on biomechanical theory, lamina cribrosa (LC) displacement, the key component of progressive glaucomatous change, is presumed to be dependent on intraocular pressure (IOP) as well as tissue stiffness of LC. In the performance of the Valsalva maneuver, both IOP and cerebrospinal fluid pressure can increase. The present study investigated the age-dependent variation of LC displacement during the standardized Valsalva maneuver in healthy subjects. Sixty-three (63) eyes (age range: 20–76 years) were prospectively underwent IOP measurement and Cirrus HD-OCT optic disc scans before and during the standardized Valsalva maneuver. During the standardized Valsalva maneuver, the IOP significantly increased from 13.2 ± 2.9 mmHg to 18.6 ± 5.2 mmHg (P < 0.001). The maximal LC depth significantly decreased in the younger age groups (age: 20 s to 40 s) but not in the older age groups (age: over 50). The BMO distance did not change significantly. Younger age (P = 0.009), a smaller increase of IOP during the Valsalva maneuver (P = 0.002), and greater baseline maximal LC depth (P = 0.013) were associated with more anterior displacement of the LC during the standardized Valsalva maneuver. Taken together, age as well as translaminar pressure dynamics seems to play a crucial role in LC biomechanics.

Frequency and Circumstances of Falls Reported by Ambulatory Unilateral Lower Limb Prosthesis Users: A Secondary Analysis.

More than 50% of lower limb prosthesis (LLP) users report falling at least once a year, placing them at high risk for adverse health outcomes such as decreased mobility and diminished quality of life. Efforts to decrease falls in LLP users have traditionally focused on developing clinical tests to assess fall risk, designing prosthetic components to improve patient safety, and identifying risk factors to recognize potential fallers. Little attention has been directed toward recording, reporting, and characterizing the circumstances of falls in LLP users. Identifying the most common types of falls could help guide and prioritize clinical and research needs. To characterize the frequency and circumstances of falls reported by unilateral LLP users. Secondary analysis of data from 2 cross-sectional studies. Outpatient clinic and research laboratory. Ambulatory unilateral transtibial and transfemoral LLP users (N = 66). None. A fall-type classification framework was developed based on biomechanical theory and published falls terminology. Self-reported falls and accompanying narrative descriptions of LLP users' falls in the previous 12 months were analyzed with the framework. Frequencies, estimated proportions, and estimated counts were compared across fall circumstances using 95% confidence intervals. Thirty-eight participants (57.6%) reported 90 falls during the previous year. All reported falls were successfully categorized using the proposed framework. Most falls occurred from disruptions to the base of support, intrinsic destabilizing factors, and a diverse set of fall patterns. Walking on level terrain was the most common activity at the time of a fall. This secondary analysis showed that falls remain frequent in ambulatory LLP users and that clinicians and researchers might wish to prioritize falls owing to disruptions of the base of support that occur while walking. Additional research with a larger sample is required to confirm and expand these results. III.

Evolving concept in treatment of intertrochanteric fractures and development of internal fixation devices

To summarize the evolving concept in treatment of intertrochanteric fractures and the development of internal fixation devices. Related literature concerning the implant devices to treat intertrochanteric fractures was reviewed and analyzed in terms of the biomechanical characteristics, clinical application, and complications. The treatment of intertrochanteric fractures has undergone an evolving concept from conservative treatment to surgical treatment. Surgery strategies include extramedullary fixation and intramedullary fixation. Intramedullary fixation has gradually become the main treatment of intertrochanteric fractures due to its minimally invasive and biomechanical advantages. However, the current intramedullary fixation system still can not reconstruct the medial cortical support of the proximal femur, which leads to some failures in the treatment of unstable fractures. The development of internal fixation of intertrochanteric fractures is based on the deep understanding and biomechanical theory of intertrochanteric fractures in clinical practice. In the future, the updated design of internal fixation devices will depend on the treatment principle of reconstruction of medial support and secondary stabilization of intertrochanteric fractures, and finally the purpose of improving success rate and reducing postoperative complications of intertrochanteric fracture will achieved.

Obesity and osteoarthritis of the knee joint: Is leptin the missing link?

BACKGROUND: Osteoarthritis (OA) involves a progressive degeneration of the articular cartilage, remodeling of the subchondral bone, and synovitis. It typically affects diarthrodial (synovial) joints including the knee joints. Obesity, which represents a body mass index (BMI) of ≥30, has been linked to OA of the knee joint. A biomechanical theory which infers that repetitive application of axial loading at the knee joint is the mechanism through which obesity causes OA has long been put forward. However, metabolic factors (adipokines) may yet be a link between OA and obesity. AIM AND OBJECTIVES: This study was performed to establish if there is a correlation between serum leptin and radiological severity of OA of the knee joint in obese individuals. MATERIALS AND METHODS: This was a prospective study carried out after ethical clearance was obtained from the hospital's ethical committee. Written informed consent was obtained from all prospectively recruited participants. Patients who met the inclusion criteria were selected by random sampling into either the obese or nonobese group based on their BMI. The patients were radiographically evaluated, and data were collected using a well-designed and structured pro forma. 5 ml of blood was collected from each patient for the analysis of serum leptin level. RESULTS: A total of 100 patients were included into this study. Fifty of these patients were obese (BMI ≥30), whereas the other fifty were nonobese (BMI CONCLUSION AND RECOMMENDATION: From the results of this study, it is concluded that there is a correlation between serum leptin levels and radiological severity of OA of the knee joint in obese patients.

Biomechanics and Bioengineering of Orthopedic and Cardiovascular Rehabilitation

Musculoskeletal problem, such as traumatic injury, osteoporosis, and osteoarthritis, is one of the leading causes of disability worldwide and is therefore a crucial branch of public health. Biomechanics has been proven to play a critical role in musculoskeletal pathology, treatment, and rehabilitation. Rehabilitation describes specialized healthcare dedicated to improving, maintaining, or restoring physiological strength, cognition, and mobility with maximized results. It helps an individual achieve the highest level of function or greatest independence and quality of life possible after illness, injury, or surgery using physical training, instruments, devices, or other methods. Advances in rehabilitation, including the theory, paradigm, protocol, modality, invention, and engineering, can improve the development of modern medicine and also the quality of life especially for the disabled and elderly people. The main focus of this special issue is on innovative theory and application of biomechanics to understand musculoskeletal pathology and to improve the techniques for the treatment and rehabilitation.

Tibiotalocalcaneal Arthrodesis Using a Straight Intramedullary Nail

Category: Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis using a hindfoot intramedullary nail has been shown to be a safe and reliable technique in patients with severe ankle and hindfoot disease. There is debate about the use of straight nails versus curved nails. Proponents of the curved nail argue that straight nails predispose to greater risk of lateral plantar nerve injury, poor calcaneal bone purchase and inability to maintain satisfactory hindfoot valgus alignment. However, the subtalar joint is a condyloid joint enabling rotation of the talus on the calcaneum to create varus/valgus position of the calcaneal tuberosity. We present a clinical series of patients undergoing TTC fusion using a straight nail assessed by clinical and radiological outcomes to establish whether theoretical risks of straight nails are reflected in clinical practice. Methods: This single centre, retrospective study of prospectively collected data on a sequential series of patients to undergo TTC fusion, with pre and post-operative weight bearing CT imaging. Data was collected on indication for procedure, co-morbidities, post-operative complications, union rate as well as clinical scores, EQ5D and MOXFQ. Weight bearing CT imaging was analysed using the validated TALUS™ (torque ankle lever arm system) method on weight bearing CT, providing calcaneal offset, hindfoot angle and hindfoot alignment. These were used as markers of hindfoot alignment. Results: 65 patients (37 males, 28 females) were included in the study, with an average age of 57 years. Average follow-up was 20 months. Indications for TTC fusion included Charcot arthropathy, talar avascular necrosis, post traumatic arthritis and non-union of previous arthrodeses. Union rate was 91% (59/65). Overall complication rate was 11% (7/65) and most were minor wound complications. There were no plantar nerve injuries noted. There were no nail cut outs from the calcaneum. On all markers of hindfoot alignment, cases showed a more physiological degree of hindfoot valgus compared to pre-operative measures. There were significant improvement in both EQ5D and MOXFQ scores (p&lt;0.05). Conclusion: We present the largest series of TTC fusion using a straight intramedullary nail and the first series to analyse hindfoot alignment using weight bearing 3D CT imaging. Our data regarding correction of hindfoot alignment is supported by biomechanical theories of subtalar varus/valgus, being related to rotatory changes at the subtalar joint, questioning the perceived need for a curved nail. This is particularly at the level of the entry point of the nail. The principles of valgus hindfoot nails are based on biomechanical laboratory studies and cadaveric studies, neither of which reflect our findings in clinical practice.

Functional morphology in the pages of the AJPA

Functional morphology in the pages of the <i>AJPA</i>