Repeatability And Clinical Application Of A Portable Knee Motion Analysis System

Background:Knee function assessment plays a very important role in clinical diagnosis and treatment.However,the existing clinical evaluation methods cannot meet the needs of doctors and patients for objective quantitative quantification of knee joint dynamic function.Optical motion capture technology can achieve non-invasive dynamic measurement of joint motion.But the technology is still mainly used in laboratory research.In clinical applications,due to the large test area,high cost,long test time and high requirements for testers,it is difficult to meet the clinical needs of domestic clinics.Therefore,based on the previous hardware accuracy verification of a portable knee motion analysis system,this paper studies the repeatability of the portable knee motion analysis system between different testers and the same tester at different time points.And this paper used this system to evaluate the efficacy of anterior and posterior of joint replacement surgery in patients with knee osteoarthritis.The system can easily and objectively obtain the six-degree-of-freedom kinematic parameters of the knee joint during walking,and the reproducibility of the system is confirmed by this study.The system provides an important solution and data reference for clinical diagnosis and treatment of knee joint diseases such as knee osteoarthritis and sports injuries.Method:(1)Two experienced testers used a portable knee motion analysis system(Opti-knee?;Innomotion Inc,Shanghai,China)to test the knee joints of 5 healthy subjects for 5 consecutive days.A total of 200 knee gait data were collected and analyzed.Correlation between different factors(tester and time)gait data was compared using Coefficient of multiple correlation(CMC),and paired t test was used to compare the differences of test data between different testers.Where CMC > 0.75 indicates a high correlation,while CMC < 0.75 indicates a medium or low correlation,and P < 0.05 indicates a significant difference.The reproducibility of the system at different testers and different test times is thus obtained.(2)Five patients with unilateral severe knee osteoarthritis were enrolled and were scheduled for total knee arthroplasty.The bilateral knee gait of the patient was collected by the system.The independent sample t-test was used to detect the bilateral gait 6-Degree Of Freedom(DOF)data before and after surgery.Result:(1)The CMC values of 6-DOF gait data of 5 healthy subjects at different time points were greater than 0.8,indicating that the system has a good correlation when tested in different days on the same subject.The CMC values of the 6-DOF gait data between the two testers were all greater than 0.95,indicating that the system has good correlation when tested by different testers.The overall CMC values of the 6-DOF gait data of the knee joint were all greater than 0.88,indicating that the overall test of the 6-DOF of the system was well correlated.Paired t-test results between different test subjects showed no significant difference(P > 0.05).(2)In the clinical application experiment,when the 6-DOF gait data of the surgical side leg before and after the operation were compared,it was found that there was no significant difference in the 6-DOF.However,the range of motion of Internal External(IE),Abduction Adduction(ABD)and Flexion Extension(FE)after surgical lateral leg surgery increased compared with preoperative.When comparing the gait data of the three rotational degrees of freedom of the patient’s bilateral legs,it was found that the range of motion of the bilateral legs increased after surgery.Before and after the operation,there was a significant difference in FE between the two legs,and there was no significant difference in ABD and IE between the two legs.The range of motion of the three rotational degrees of freedom on the non-operative side is always greater than the surgical side.When comparing the gait data of the three displacement degrees of freedom of the bilateral legs,it was found that there was a significant difference in the Anterior Posterior(AP)of the bilateral legs before surgery,and there was no significant difference after operation.There was no significant difference in the Distal Proximal(DP)of the bilateral legs before surgery,and there were significant differences after surgery.There was no significant difference in the Medial Lateral(ML)before and after surgery.Conclusion:(1)This study conducted a repeatability analysis of the portable knee motion analysis system.It was found that the system was reproducible in different days of the same subject,and the repeatability was good under different testers’ operation.The overall repeatability of the 6-DOF is good.,indicating that the portable knee motion analysis system has good feasibility and repeatability,and is suitable for gait function detection.(2)This study used this portable system to measure knee gait 6-DOF data for knee osteoarthritis before and after total knee arthroplasty.It was found that the range of IE,ABD,and FE in the non-surgical knee joints were larger than those on the surgical side before and after surgery.Compared with the scope of activities before the surgery,in addition to AP and DP,the scope of activities other bilateral knee surgery has increased,which was closer to the normal range of motion.The results showed that the three rotation angles and ML motion range were improved six weeks after operation.Through this research,it is proved that the system can quickly collect and accurately display the six-degree-of-freedom gait data of patients with clinical knee osteoarthritis.The system presents clinical results in a more objective form of data,contributing to the patient’s future treatment plan development and exercise mechanism research.