The impact of hip abductor muscle status on in vivo joint loads through kinematics and muscle activity 51 months following total hip arthroplasty

Background: Well-established clinical scores show that total hip arthroplasty (THA) in primary hip osteoarthritis alleviates pain and markedly improves the performance of activities of daily living (ADLs). However, objective measurements show that THA patients’ movement and electrophysiological patterns do not match those of healthy age- matched individuals. Surgical incision as well as intraoperative soft tissue traction and compression cause iatrogenic damage of the hip muscles, which is associated with their atrophy and fatty degeneration. An unfavorable muscle status may negatively affect joint loads. An improper in vivo hip joint resultant contact force (Fres) may shorten an implant’s lifespan and also determine functional outcome following THA. This retrospective analysis aimed to identify whether kinematics and electrophysiological activity mediate the impact of structural muscle impairment on kinetics. Materials and methods: In order to determine the Fres, instrumented femoral prostheses were implanted via a direct lateral approach. Nine patients (two females, seven males) participated in synchronous recordings of load patterns and surface electromyography along with three-dimensional mapping of motion sequences at a mean of 51 months (period: 35-64 months) postoperatively. The hip movement patterns of five ADLs (level walking, ascending stairs, descending stairs, standing up, sitting down) and the electrophysiological activity of the hip abductors gluteus maximus muscle, gluteus medius muscle, and tensor fasciae latae muscle (TFL) were assessed and correlated with both the hip abductor muscle status (total muscle volume [TMV], fat ratio [FR]) evaluated by postoperative computed tomography images and the in vivo Fres. Findings: Across all ADLs, the results yield high inter-individual variability. Compared to asymptomatic control groups in the literature, this study’s patients produced reduced extension and lower sagittal range of motion (ROM) in level walking, while stair negotiation resulted in higher flexion and greater ROM in the sagittal plane. Particularly TFL activity patterns are shaped by irregularities and hyperactivity. TMV and FR have an effect on both motion patterns in the sagittal and frontal planes and shape and timing of muscle activity. Furthermore, compensatory movement strategies and abnormal muscle activity may lead to not only higher but also lower hip joint loads. Interpretation: The data do not provide conclusive evidence of muscle damage affecting joint loads via atypical movement and electrophysiological patterns. Overall, however, the results support the hypothesis that structural impairment of hip abductors may lead to the development of pathomechanical movement patterns and irregular muscle activity, which in turn may adversely affect hip joint loads.Fragestellung: Gängige klinische Scores zeigen, dass die Implantation einer Hüfttotalendoprothese bei primärer Coxarthrose die Schmerzen der Patienten bedeutend lindern und die Ausführung von Aktivitäten des täglichen Lebens merklich verbessern kann. Ergebnisse objektivierbarer Messmethoden zeigen jedoch, dass weder die Bewegungsmuster noch die Muskelaktivität dieser Patienten denen gesunder Gleichaltriger entspricht. Die Implantation einer Hüfttotalendoprothese führt entweder über ein Schnitt- oder ein Quetschtrauma zu einer iatrogenen Schädigung der Hüftmuskulatur, was mit deren Atrophie und Verfettung einhergeht. Ein abträglicher Muskelstatus kann sich ungünstig auf die Hüftgelenksbelastung auswirken. Die resultierende Hüftkontaktkraft ist ein bedeutender Faktor für die Haltbarkeit einer Hüfttotalendoprothese, die das funktionelle Ergebnis eines endoprothetischen Ersatzes mitbestimmt. Das Ziel dieser retrospektiven Analyse war es, das Verständnis für die auf die in vivo resultierende Hüftgelenksbelastung wirkenden Zusammenhänge zwischen periartikulärer Muskelschädigung, pathologischen Bewegungsabläufen und irregulärer Muskelaktivität zu erweitern. Material und Methodik: Zwecks in-vivo-Bestimmung der Hüftkontaktkräfte erfolgte per transglutealem Zugang die Implantation von instrumentierten Hüfttotalendoprothesen. Neun Patientinnen und Patienten (zwei weiblich, sieben männlich) nahmen zum durchschnittlichen Zeitpunkt von 51 Monaten (Zeitraum: 35-64 Monate) postoperativ an synchronen Belastungsmessungen, dreidimensionalen Bewegungserfassungen und Oberflächen-Elektromyographie-Messungen teil. Die Bewegungsmuster der Hüfte von fünf Aktivitäten des alltäglichen Lebens (ebenes Gehen, treppauf Gehen, treppab Gehen, Aufstehen, Hinsetzen) sowie die Muskelaktivität der Hüftabduktoren (M. gluteus maximus, M. gluteus medius, M. tensor fasciae latae) wurden erfasst und jeweils mit dem anhand von postoperativen computertomographischen Aufnahmen evaluierten Muskelstatus (Gesamtvolumen, prozentuale Verfettung) und der Hüftkontaktkraft korreliert. Ergebnisse: Über alle Aktivitäten hinweg ergab sich aus den Messergebnissen eine hohe interindividuelle Streuung. Im Vergleich zu symptomlosen Kontrollgruppen aus der Literatur zeigte sich beim Gehen eine reduzierte Extension und ein geringerer Bewegungsumfang in der Sagittalebene. Beim Treppengang hingegen erfolgten eine höhere Flexion und ein größerer Bewegungsumfang in der Sagittalebene. Insbesondere die Aktivitätsmuster des M. tensor fasciae latae waren von Unregelmäßigkeiten und Überaktivität geprägt. Die Daten zeigen auf, dass Muskelvolumen und -verfettung sowohl die Hüftbewegung in der Sagittal- und Frontalebene als auch die elektrophysiologische Form und den Zeitablauf von Muskelaktivität beeinflussen. Die Ergebnisse weisen ferner darauf hin, dass beeinträchtigte Bewegungsabläufe und gestörte Muskelaktivität nicht nur eine Erhöhung, sondern auch eine Verminderung der Hüftkontaktkraft bewirken können. Schlussfolgerung: Die Daten liefern keine stichhaltigen Beweise für einen durchgehenden Effekt einer Muskelschädigung über atypische Bewegungsabläufe und elektrophysiologische Signale auf die Gelenkbelastungen. Jedoch bekräftigen die Ergebnisse insgesamt die Hypothese, dass eine strukturelle Beeinträchtigung der Hüftabduktoren zur Entstehung von pathomechanischen Bewegungsmustern und unregelmäßiger Muskelaktivität führen kann, was sich wiederum ungünstig auf die Hüftkontaktkräfte auswirken kann

Rehabilitation Engineering

Population ageing has major consequences and implications in all areas of our daily life as well as other important aspects, such as economic growth, savings, investment and consumption, labour markets, pensions, property and care from one generation to another. Additionally, health and related care, family composition and life-style, housing and migration are also affected. Given the rapid increase in the aging of the population and the further increase that is expected in the coming years, an important problem that has to be faced is the corresponding increase in chronic illness, disabilities, and loss of functional independence endemic to the elderly (WHO 2008). For this reason, novel methods of rehabilitation and care management are urgently needed. This book covers many rehabilitation support systems and robots developed for upper limbs, lower limbs as well as visually impaired condition. Other than upper limbs, the lower limb research works are also discussed like motorized foot rest for electric powered wheelchair and standing assistance device

Support for total hip replacement surgery: Structures modeling, Gait Data Analysis and Report system

For the treatment of advanced damages of hip joints, Total Hip Arthroplasty is well proven. Due to the different mechanical properties of the prosthesis material and the bone tissue, a partial unloading of the periprosthetic bone occurs. The bone cement causes reduction in bone density as a result of removal of normal stress from the bone, leading to weakening of the bone in that area and the fracture risk increases. Bone loss is identified as one of the main reasons for loosening of the stem. Otherwise, thanks to the press-fit of the non-cemented stem achieved by surgery, the bone layers immediately adjacent to the stem are preloaded, thus encouraged growing, and the bone getting stronger. The non-cemented stem would be the better choice for every patient, but the question remains if the femur can handle the press- fitting surgery. This studies aim to develop a monitoring techniques based on Gait analysis and bone density changes to assess patient recovery after Total Hip Arthroplasty. Furthermore, to validate computational processes based on 3D modeling and Finite Element Methods for optimizing decision making in the operation process and selecting the suited surgical procedure. A vision could be minimizing risk of periprosthetic fracture during and after surgery. Patients: The sample presents 11 patients receiving cemented implant and 13 for the uncemented. Patients are grouped by type of implant. Three checkpoints were considered: before, after operation and one year later. CT scans, gaitrite and kinepro measurements have been realized. Main outcome measures: Fracture risk probability is higher in bone with low bone mineral density; therefore bones are more fragile in elderly people. BMD is indeed one parameter considered among all the observations. Periprosthetic fracture of the femur is a rare but complex complication of THA, and requires demanding surgery. As such, they result in considerable morbidity and dysfunction. Thus, tests of force reaction have been accomplished to support surgeons during the prosthesis fitting. Identification of risk factors for fracture will improve preoperative counseling and aid primary prevention. To assess eventual improvements or find out trends respecting the implant used, gait data have been collected and compared with muscles mass modeling

The biomechanical determinants of sports related groin pain in athletes.

PhDIntroduction Sports related groin pain (SRGP) is common, debilitating and often recurrent. Rehabilitation that addresses strength and flexibility deficits has only moderate effects. Recurrence of SRGP remains high, suggesting that deficits remain after apparently successful rehabilitation. The aims of this thesis were to inform best practice by (i) systematically reviewing the literature on biomechanical factors associated with SRGP (ii) investigating muscle activation and movement patterns associated with SRGP in both professional and amateur athletes; (iii) investigating muscle activation and movement patterns immediately after groin injury alongside their response to standard rehabilitation. Methods A systematic review with meta-analysis was completed. 84 athletes from four sports (56 professional and 28 amateur) were recruited and clinically assessed. Hip joint kinematics and surface electromyography of gluteus medius (GM) and adductor longus (AL) muscles were measured while performing selected manoeuvres. A further 5 athletes had serial measures during traditional rehabilitation from acute injury. Results The review found strong evidence for decreased adductor flexibility as a risk factor; and decreased adductor strength and external rotation range of movement being associated with SRGP. The GM:AL ratio in injured professionals was increased due to reduced AL activation, a decreased GM:AL ratio was found in amateurs due to a decrease of GM activation. In injured professionals hip kinematic change matched the sEMG findings (increased abduction), whereas no consistent pattern was observed in amateurs. Longitudinal study participants 7 improved clinically after groin injury, but the muscle activation and movement patterns did not alter. Conclusion These studies identified clear muscle activation differences that extend existing the literature while the kinematic changes are novel. Further, participation level and sports-specific subgroups had not previously been identified but are clearly evident. Published guidelines require amendment, while clinical innovation that addresses sub-group specific biomechanical factors in rehabilitation programmes may inform prevention, improve outcome and certainly warrant further research

La fonction musculaire au niveau de la hanche chez les patients présentant un conflit fémoro-acétabulaire symptomatique

Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint, which could lead to hip pain and functional disability. Aim of this thesis was to investigate hip muscle function in patients with a symptomatic FAI. Hip muscle function was first investigated before patients underwent any surgical treatment for managing FAI. It was shown that they present with reduced hip muscle strength (i.e., muscle weakness), probably due to hip muscle inhibition. Nevertheless, hip muscle weakness was not associated with exaggerated hip muscle fatigue. Hip muscle strength recovery was then evaluated in a series of patients after hip arthroscopy to treat FAI. These patients demonstrated a good recovery for all hip muscle groups, except for hip flexors. The case of a professional ice hockey player who underwent bilateral hip open surgeries for treating bilateral FAI was also documented. This report showed that iliotibial band dehiscence could occur after hip open surgery, thereby preventing hip abductor strength increase during rehabilitation and delaying the return to sport. In addition, the assessment of the rate of force development scaling factor for the hip muscles was evaluated in a group of healthy adults. This parameter seems to be promising for the evaluation of hip muscle inhibition. The testing protocol was feasible and reproducible for hip adductors, external rotators and flexors. Taken as a whole, these findings show that patients with symptomatic FAI demonstrate an impaired hip muscle function, which is however mainly resolved after surgical treatment.Le conflit fémoro-acétabulaire (femoroacetabular impingement, FAI) est une pathologie mécanique de la hanche qui peut causer des douleurs et limitations fonctionnelles. Le but de cette thèse était d’étudier la fonction musculaire au niveau de la hanche chez des patients présentant un FAI symptomatique. La fonction musculaire de la hanche a été évaluée, dans un premier temps, chez des patients avant qu’ils ne subissent une opération. Ces patients démontraient un déficit de force qui pourrait être expliqué par de l’inhibition musculaire. Cependant, ce déficit de force n’était pas associé à une plus grande fatigabilité musculaire. Dans un deuxième temps, les altérations de force musculaire ont été évaluées chez des patients ayant subi une arthroscopie de la hanche. Après l’opération, les patients récupéraient un niveau de force normal au niveau de tous les groupes musculaires de la hanche excepté les fléchisseurs. Le cas d’un joueur de hockey sur glace ayant subi une chirurgie ouverte aux deux hanches pour traiter un FAI bilatéral a aussi été décrit. On a démontré que la déhiscence de la bandelette iléo-tibiale pouvait survenir après chirurgie, empêcher l’augmentation de force musculaire des abducteurs de la hanche, et retarder la reprise du sport. Enfin, un protocole d’évaluation du taux de développement de la force normalisé, variable permettant d’estimer l’inhibition musculaire de la hanche, a été proposé chez des sujets sains. La fiabilité et reproductibilité des résultats ont été montrées au niveau des adducteurs, rotateurs externes, et fléchisseurs de la hanche. Ces résultats montrent que ces patients ont une fonction musculaire altérée au niveau de la hanche, qui est toutefois récupéré après une opération

Subject-Specific Musculoskeletal Modeling of Hip Dysplasia Biomechanics

Developmental dysplasia of the hip (DDH) is characterized by abnormal bony anatomy, causes pain and functional limitations, and is a prominent risk factor for premature hip osteoarthritis. Although the pathology of DDH is believed to be mechanically-induced, little is known about how DDH anatomy alters hip biomechanics during activities of daily living, partly due to the difficulties with measuring hip muscle and joint forces. Musculoskeletal models (MSMs) are useful for dynamic simulations of joint mechanics, but the reliability of MSMs for DDH research is limited by an accurate model representation of the unique hip anatomy. To address such challenges, this research used subject-specific MSMs to identify how DDH hip biomechanics are influenced by the abnormal bony anatomy. First, to determine the importance of model specificity, personalized MSMs using image-based bony anatomy and muscle paths were compared against MSMs with generic anatomy. MSMs with subject-specific anatomy estimated significantly different hip muscle and joint forces compared to generic models, thus are necessary for delineating DDH-specific pathomechanics. Next, image-based MSMs were used to calculate hip muscle moment arm lengths and lines of action during gait, to determine how DDH alters dynamic muscle force production. Hips with DDH had reduced abductor moment arms, which elevated muscle and joint forces in the medial direction. Results confirmed hip muscles’ contributions to joint overloading, which could in turn interact with the abnormal anatomy to induce pathomechanics at the articular level. To verify this phenomenon, hip loading estimated from MSMs was projected to the pelvis anatomy to predict acetabular edge loading during two movement tasks, gait and double-legged squat. Results showed that edge loading was elevated by the shallow acetabulum of DDH, and was highly dependent on the kinetics and muscle demand of task-specific movements. These findings could help explain the prevalence of region-specific labral tears in DDH. Overall, this research provided new insights into the relationships among bony anatomy, muscle function, and joint biomechanics in hips with DDH. The outcomes can refine our understanding of mechanically-induced DDH pathology, and inform patient-specific clinical assessments and treatments to improve long-term hip joint health

Evaluating footwear “in the wild”: Examining wrap and lace trail shoe closures during trail running

Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products