Saudi Cultural Missions Theses & Dissertations
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Item Open Access Knee Joint Morphology and Biomechanics in Athletes and People Following ACL Reconstruction(Saudi Digital Library, 2025) Alotaibi, Sultan Saud H; Monty, Jason PatrickComprehensive understanding of knee biomechanics and bone morphology remains crucial for advancing treatment strategies for knee pathologies. Despite this importance, current research provides insufficient data on knee bone morphology and biomechanical function during activities of daily living, particularly regarding athletic populations and individuals following anterior cruciate ligament reconstruction (ACLR) surgery. This thesis addresses these knowledge gaps through measuring and describing: (a) the structural profile (i.e. geometrical shapes) of knee bones (i.e. femur, tibia, and patella), and (b) the knee biomechanical profiles at the tibiofemoral (TF) and patellofemoral (PF) joints in athletic populations and individuals following ACLR surgery. The methodology employed precise measurement of patellofemoral and tibiofemoral joint kinematics (i.e. 6-degree-of-freedom motion) and arthrokinematics (i.e. condylar motion, location of TFJ center of rotation, and the location of the contact centers) parameters, during activities of daily living (i.e. level walking, downhill walking, and stair ascent). Advanced statistical-shape-modeling approaches were utilized, alongside linear measurements, to detect morphological differences. Four knee groups were analyzed: intact knees of athletes (HKA), intact knees of non-athletes (HKS), ACL reconstructed knees of athletes (ACLR), and their contralateral knees (Contra), through six comprehensive comparisons. The methodology includes a) one comparison between athlete and non-athlete knees [i.e. HKA vs control group (HKS)] to explore the structural & biomechanical profiles of the athletic knees, along with b) five comparisons to explore the structural & biomechanical profiles of the reconstructed knees [i.e. ACLR vs its control groups (Contra, HKA, and HKS)] and their contralateral knees [i.e. Contra vs its control groups (HKA and HKS)]. The morphological findings revealed distinct patterns of bone remodeling (i.e. bone shape changes) across knee bones, characterized by coordinated changes. ACLR knees exhibited ovoid femoral condyles, narrower intercondylar notches, increased distal sulcus angle, along with posteromedial tibial enlargement and greater patellar convexity. Contralateral knees displaying intermediate morphological changes that challenge the conventional use of the uninjured limb as a control reference. Healthy athletic knees demonstrated distinct morphological adaptations, including wider intercondylar notches and modified plateau slopes. Our comprehensive morphological assessment reveals remarkable plasticity of the knee joint complex, highlighting crucial implications for surgical planning, rehabilitation protocols, and long-term joint health management. The biomechanical findings, utilizing mobile biplane X-ray imaging system, revealed deviations from normal knee joints’ kinematics and arthrokinematics. Specifically, both ACLR and contralateral knees exhibited enhanced anterior patellar translation, greater patellar extension, persistent medial tibial shift, and increased anterior tibial translation. ACLR knees showed reduced tibial internal rotation along with "quadriceps avoidance" gait patterns, characterized by minimal flexion range changes. Condylar motion analysis reveals posterior displacement of the medial femoral condyle and a deficit in the natural femoral rollback mechanism in ACLR knees, while both ACLR and contralateral knees display reduced medial-lateral range of motion. Healthy athletic knees exhibit elevated lateral tibial shifts, superior patellar translation, and posterior condylar shifts. The center of rotation of the TFJ shifts posteriorly in ACLR, contralateral and athletic knees. Contact kinematics analysis shows that athletic populations demonstrate more lateral and superior femoral contact (in the medial compartment) while both ACLR and contralateral knees show greater medially-directed shift of femoral contact location (in the lateral compartment). Task-specific strategies during ramp descent and stair ascent revealed different kinematic patterns than level walking, emphasizing limitations of relying solely on level walking assessments in post-ACLR evaluations. These findings underscore the complex association between surgical intervention, athletic training, and joint mechanical adaptation, necessitating comprehensive rehabilitation accounting for TFJ and PFJ mechanics, bilateral adaptations, and task-specific demands. This PhD research provides insights into detection, diagnosis, and management of prevalent knee problems while serving as a foundation for future investigations into knee joint function and adaptation mechanisms.62 0Item Restricted STUDY OF PAIN, MOTION, AND MUSCLE ACTIVITY FOR LOWER LIMB AMPUTEES(University of Birmingham, 2024) Alsayed, Khalid; Ziyun, DingThis thesis investigates the interplay between pain and gait biomechanics in unilateral transtibial amputees (TTAs) to understand compensatory mechanisms and adaptations in the musculoskeletal system. The aim is to explore how pain influences gait performance by analysing spatial and temporal parameters, kinematics/kinetics, muscle activity, and pain outcomes using advanced tools such as motion capture, force plates, electromyography (EMG), and musculoskeletal modelling. The study first developed a rigorous experimental protocol to acquire multi-modal biomechanics gait data (i.e., marker trajectories, ground reaction force, EMG, and self-reported pain measures). This protocol was then successfully applied to capture gait data from eight able-bodied controls and six individuals with transtibial amputation (TTA). The data analysis and modelling identify significant gait deviations in TTAs, including reduced walking speed, altered stride length, and asymmetrical ground reaction forces, correlating these with pain levels. Advanced musculoskeletal simulations provide further insights into joint kinematics, kinetics, and muscle forces, highlighting the compensatory strategies adopted by amputees. The findings emphasise the need for multidisciplinary approaches in rehabilitation, integrating biomechanical analysis and pain management to enhance mobility and quality of life for TTAs. This research bridges key knowledge gaps, offering practical recommendations for improved prosthetic development and rehabilitation strategies.68 0Item Restricted The Immediate Effect of Changing the Footplate Profile of a Rigid Ankle-Foot Orthosis (AFO) on Lower Limb Kinematics and User Feedback(University of Strathclyde, 2022-08-05) Albasri, Renad; Cox, ChrisBackground: Rigid ankle-foot orthoses (AFOs) are widely used within clinical practice to address pathological gait. A literature review search illustrated AFO footplate variations are under investigated, despite this being a key design feature in AFO prescription. There are currently no studies investigating how dorsiflexing the footplate would affect lower limb kinematics and user feedback. Objective: To evaluate the effects of dorsiflexing the footplate on hip, knee and ankle kinematics and user feedback. Study design: Feasibility study. Methods: Healthy participants (n = 10) were tested under four test conditions: shoe- only, rigid AFO with 0° of dorsiflexion at the footplate, rigid AFO with 15° of dorsiflexion at the footplate and rigid AFO with 30° of dorsiflexion at the footplate. Data on hip, knee and ankle kinematics was obtained from midstance to pre-swing. User feedback was established through verbal free text comments and scoring the visual analogue scale. Results: The most significant finding in this study is identifying 100% of the participants preferred a dorsiflexed footplate over a flat footplate. No statistically significant differences were observed; however, trends in hip, knee and ankle kinematics were identified. Conclusion: We recommend orthotists consider dorsiflexing the footplate of rigid AFOs as part of routine clinical practice. Further research is required to comprehend the effects of dorsiflexing the footplate on pathological gait and to determine a suitable prescription criterion.12 0Item Restricted THE BIOMECHANICAL EFFECTS OF CROSS-LEGGED SITTING ON THE LOWER LIMBS AND THEIR IMPLICATIONS FOR REHABILITATION(University of Dundee, 2024-02-01) Alsirhani, Hadeel; Wang , Weijie; Arnold, GrahamProject Title: The biomechanical effects of cross-legged sitting on the lower limbs and their implications for rehabilitation. Background: Balanced coordination between several body parts could play a significant role in protecting these body parts from injury and the body posture from deformities, particularly during the sitting position, as sitting constitutes more than half of people’s daily activities. Although the cross-legged sitting posture is widely practiced as part of the daily routine in certain communities, limited research is focused on the effects of CLS on biomechanics. Therefore, the aim of this study was to analyze the biomechanical effects of cross-legged sitting on the lower limb joints and muscles and investigate the effect of CLS on body balance. Methods: Thirty healthy volunteers were invited to participate in this study: 15 males and 15 females. Cross-legged sitting (CLS) was analysed biomechanically by comparing the situation before and after 20 minutes of CLS, based on temporospatial measures, kinetic and kinematic parameters, muscular electrical activity, muscular strength, and a static and dynamic balance assessment. The instruments used were the Vicon motion capture system with a combination of the force platform, Electromyography, Force sensor, the single-leg stance test, and the four-square step test. The variables were analysed using SPSS® version 28. Results: CLS can affect the gait’s temporospatial parameters positively by increasing the cadence, increasing the walking speed, and decreasing the stride and step time. In addition, the kinematic ROM for all the lower limb joints increased post-CLS compared to pre-CLS in all planes except for the knee sagittal ROM, which decreased significantly following CLS. Considering the kinetic parameters, the medial and lateral forces increased significantly in terms of RoF during walking post-CLS compared to pre-CLS xviii in almost all of the lower limb joints, including the hip, knee, and ankle on both sides. Moreover, the left knee and right ankle joints were similar in terms of an increased anterior force post-CLS, while the posterior force was increased in both sides of the hip joints and decreased significantly in only the left ankle. Furthermore, the compression force increased significantly on both sides of almost all of the lower limb joints except for the right knee, while the tension force improved noticeably on only the right hip, left hip, and left knee joint. When comparing walking pre-CLS with post-CLS according to the moment values, it was observed that the flexion/extension moment rose significantly post-CLS in the hip and knee joints in terms of ROM, while only the plantar flexion moment increased in the right ankle during walking post-CLS compared to pre-CLS. However, it was noticed that only the left leg displayed a significant increase in the knee valgus moment, as well as the hip and ankle abduction moment. Regarding the rotation direction, the left knee displayed a significant decline in terms of the internal/external rotational moment. Regarding the power values of all of the lower extremity joints, it was found that all of the hip, knee, and ankle joints were similar in terms of displaying increased RoP during the gait after 20 min of CLS compared to before. Regarding muscular electrical activity and muscular strength, only the lateral gastrocnemius muscle was activated significantly post-CLS. In the case of muscle strength, the hip extensor and knee flexor muscles became significantly stronger (by approximately 14%) post-CLS compared to pre-CLS roughly and the ankle plantar flexor’s maximum force increased noticeably, by about 4%, post-CLS. Regarding balance, CLS had a positive impact on the dynamic balance, while the static balance was affected negatively post-CLS compared to pre-CLS. Conclusion: CLS has a positive impact on all of the lower limb joints and muscles apart from the knee Flexion/Extension angle and Internal/External rotational moments. Depending on the muscular results, CLS can be safely included in people’s daily routine xix and in any rehabilitation programmes to improve the muscular strength that is responsible for hip extension, knee flexion and ankle plantar flexion, and increase the range of motion accordingly. However, CLS should be avoided for any patients suffering from static balance disturbance.55 0