Adaptive Motion Features In Older Women With Knee Osteoarthritis During Walking

Objective:Osteoarthritis(OA)is one of the most common types of arthritis.The elderly,women and obese people are the main susceptible groups to this degenerative disease.According to the World Health Organization(WHO),by 2020,increasing life expectancy and the population’s ageing made OA the fourth leading cause of disability.As the largest synovial joint in the human body,the knee joint has a much higher OA probability than other joints due to its high frequency of use and excessive load.Given the rapid growth of the Chinese elderly population and the increasing obesity rate,the number of KOA individuals is likely to increase significantly in the coming years.Therefore,the current severe development trend of KOA has caused a great negative impact on the development of individuals,families and society.At present,the management system of KOA in China has not been improved.The reason is that,compared with other chronic cardiovascular diseases,KOA is usually regarded as a"normal phenomenon of ageing",and there is a lack of large-scale,normative and cross-population epidemiological investigation on bone and joint health.Therefore,how to solve the disease burden challenge based on the needs of patients so that more patients can benefit from standardized treatment,improve the health status of bones and joints,and improve the quality of life,all sectors of society must work together to solve the problem.In the absence of a complete cure method,clinical interventions focus on relieving joint pain and retaining and improving joint function,while non-pharmacological interventions focus on sports biomechanics.How to adjust the load in the knee joint is the top priority in the study of KOA intervention.However,at present,there are still many barriers to the use of this approach.For example,implementing this method requires a rigorous experimental environment,and it isn’t easy to popularize it in the clinical field.Whether other biomechanical indicators can be used to estimate the knee load has not been considered.The above are indispensable theoretical basis and application reference for KOA rehabilitation intervention and daily management(including early diagnosis,severity assessment,intervention plan formulation and effect evaluation).To sum up,the overall research purpose of this project is:to take walking as the motor task and elderly female KOA as the target population,to deeply explore the changes in the adaptive motor characteristics of the KOA group when walking more,and to clarify the unique "adaptive adjustment" mode of KOA group;The biomechanical factors which are sensitive to the change of knee load need to be identified,and their interrelationships need to be established to guide the formulation of powerful and efficient exercise intervention mode,to achieve the individualized and stepwise goals of early diagnosis,early treatment,early intervention and treatment strategies for KOA.Study 1Purpose:To explore the influence of changes in knee adduction moment during walking on the motion characteristics of the adjacent hip,ankle and other segments(foot,pelvis and torso)in older women with KOA compared with healthy older women,to obtain the multi-segment biomechanical indicators that are more sensitive to the intervention of KOA diseases.Method:Subjects:Subjects were selected in the form of a questionnaire(knee pain,immobility,and age),followed by clinical means--standing radiographic images of the knee(i.e.,X-rays):Anteroposterior and lateral radiographs)were used to diagnose and stage KOA(K-L grading),and 15 KOA subjects and 15 age-matched healthy controls were eventually included in this study.Equipment construction:The gait analysis experiment was completed in the experimental hall of the Sports Skill Research Center of the School of Kinesiology.A motion capture system with 16 infrared cameras was used to track the motion trajectories of 52 markers affixed to bony markers all over the body,with a sampling frequency of 100 Hz.Cooperate with two Kistler force plates embedded in the middle of the walkway to collect the ground reaction force during walking simultaneously.The sampling frequency is 1000 Hz.Data analysis:Vicon system supporting software Nexus and Visual 3DTM were used for subsequent data processing and analysis.1.Spatial and temporal parameters of gait--stride length,single step length,stride width,gait cycle length and stride speed;2.Kinematics--joint angles of the hip,knee and ankle in the frontal plane,and the special moment values related to KOA disease were extracted for between-group comparative analysis;3.Kinetics--net moments of joints in the hip,knee and ankle joints and special moment values associated with KOA diseases were extracted for between-group comparative analysis.Results:(1)Compared to the healthy control group,elderly female KOA subjects had a significantly lower gait speed(t=2.129,P=0.04);(2)Compared to the healthy control subjects,abduction angle of hip increased significantly(t=4.561,P<0.0001);The pelvis and trunk corresponding to the first peak of KAM was significantly inclined to the affected side(t=4.396,P=0.0001;t=10.03,P<0.0001),the foot progression angle corresponding to the second peak of EKAM was shown as the toe-out(t=3.351,t=0.002),the pelvic and trunk significantly inclined to the affected side(t=3.028,P=0.0052;t=3.135,P=0.004);(3)The corresponding value of the ankle joint frontal plane torque at the second peak of KAM,namely ankle joint torque 2,the first peak of KAM,there is a statistically significant difference between the groups(t=17.73,P<0.0001;t=14.42,P<0.0001);Study 2:Purpose:In this study,we further explored the changes of spatial and temporal parameters of gait,lower limb joints and other body parts in KOA older women with different body weights.We identified the unique "adaptive changes" process in older women with KOA during walking.At the same time,the relationship between the above motion adjustment and the knee joint adduction moment was established by mathematical means,and their interaction was discussed.Method:Subjects:The recruitment and screening conditions were the same as those in Study 1.60 KOA subjects were included.Since there were overweight and obesity in the KOA group,and the weight would also affect the load of the knee joint,the subjects in Study 2 were finally divided into three groups according to the Chinese adult body mass index standard(normal BMI:18.5-23.9 kg/m2;overweight BMI:24.0-27.9 kg/m2;obesity BMI:≥28.0 kg/m2),which are recorded as BMI(standard),BMI(overweight),and BMI(obese)in order.Data processing and analysis:same as the study I,related indicators:1.Spatial and temporal parameters of gait;2.Kinematics-foot progression angle,pelvis and trunk inclination angle,and special moment values related to KOA disease were extracted for between-group comparison analysis;3.Kinetics--the net moment of the knee joint in the frontal plane,and two peaks of KAM was extracted for between-group comparison analysis.Results:(1)In the process of walking,there were statistically significant differences in stride length(F=3.951,P=0.02),step length(F=3.737,P=0.03)and gait speed(F=4.851,P=0.01),which were mainly reflected in the differences between the BMI(obese)group and the BMI(normal)group.However,there were no differences between the two groups in stride width and gait cycle length.(2)In the three groups of KOA subjects,compared to the standard group,the pelvis and trunk significantly inclined to the affected side or the more severe side of KOA at the first peak of KAM(F=8.449,P=0.0006;F=4.663,P=0.01),and the foot progression angle increased significantly at the corresponding time of the first and second KAM peaks,which showed an obvious toe-out(F=5.553,P=0.006;F=11.51,P<0.0001);(3)BMI,stride speed,trunk tilt angle,pelvic tilt angle and foot progression angle,as the core parameters,have a specific linear relationship with the first and second peaks KAM.Conclusion:(1)Compared with the healthy older women,the increased knee joint adduction moment in the elderly KOA women led to some adaptive motion changes.These"adaptive motion features" was shown as follows:gait speed decreases,hip abduction angle at the loading response increases,ankle valgus moment at the terminal stance increases,foot progression angle at the terminal stance decreases,the pelvis and trunk inclined to the affected side.Furthermore,in older women with the same grade of KOA,the knee joint adduction moment gradually increased with the increase of body weight,and the above adaptive changes were more prominent.(2)The increase of knee adduction moment led to significant adaptive motion changes in gait speed,foot progression angle,pelvis and trunk tilt angle.The multiple linear regression model based on the above indexes and body mass index can quickly estimate the double peak value of knee adduction moment,which is easy to be applied in the diagnosis and intervention of KOA.(3)The results of multiple linear regression showed that the relative influence of body weight and foot progression angle on the peak value of knee adduction moment was significant.The decrease of body weight and the increase of foot progression angle could reduce the peak value of knee adductive moment,which was the universal concern of the gait modification for older women with KOA.