| Hip pain is a common condition in joint and sports medicine clinics,and FemoralAcetabular Impingement(FAI)is one of its common causes.FAI is an anatomical abnormality of the hip joint,i.e.,femur and/or acetabulum that collides proximally to the femur and the acetabular margin at the end of hip motion,resulting in injury to the acetabular labrum and/or adjacent acetabular cartilage,resulting in hip pain symptoms,which are mainly manifested as pain in the inguinal area(especially pronounced in combination with hip flexion and internal rotation),and limited internal rotation during hip flexion.With the change of hip joint angle of motion,abnormal contact between the femoral head and neck junction area and its corresponding acetabulum occurs,resulting in hip pain,limited mobility,and secondary acetabular labral and cartilage damage,and studies have shown that the occurrence of early osteoarthritis of the hip joint is closely related to this.Abnormal development of the femur or acetabulum,resulting in an abnormal matching relationship between the femoral head and acetabulum,is the main cause of impact and is closely related to the extent of the acetabular labral injury.At present,the clinical and experimental studies on acetabular labral injury are mainly anatomical studies,and there is a lack of research on the relationship between hip joint angle of motion and the extent of acetabular labral injury.Moreover meniscus and acetabular labrum are both fibrocartilage structures histologically,but they play completely different physiological roles in different joints,and the differences in biomechanical properties have not been compared.In this study,the compressive and tensile resistance tests of the biomechanical properties of the hip labrum were carried out,and the biomechanical properties of the knee meniscus were compared,which provided a biomechanical basis for hip labral injury secondary to bony impact.The Vicon light capture system was used to study the normal range of motion of the hip joint,guide and limit the range of hip joint angle of motion in FAI patients,establish a three-dimensional model of hip joint in FAI patients,simulate hip joint movement according to the range of hip joint motion obtained in the early stage and use the threedimensional model,the three-dimensional model is used to simulate hip joint movement,the relationship between hip joint movement angle and labrum impact range in different types of FAI patients is studied,and the range of acetabular labrum injury in FAI patients is statistical,which provides experimental evidence for the mechanism and injury range of labrum injury in FAI patients,and provides reference for the clinical treatment of labrum injury.Part 1 A comparative study of the biomechanical properties between meniscus and acetabular labrumBackground: The meniscus and acetabular labrum play a vital role in maintaining knee and hip stability,respectively.Although the meniscus and acetabular labrum are the same fibrocartilage histologically,they play different physiological functions in different joints,this part of the study will perform compression and tensile tests on the biomechanical properties of the meniscus and acetabular labrum,compare differences in the biomechanical properties of the meniscus and acetabular labrum,and analyze the biomechanical evidence of acetabular labral injury due to femoral acetabular impingement.Objective: Through the experimental study of biomechanical properties of meniscus and acetabular labrum,compare differences in the biomechanical properties of the meniscus and acetabular labrum,and analyze the biomechanical evidence of acetabular labral injury due to femoral acetabular impingement.Methods: Under the condition of informed consent of all patients,the acetabular labrum and knee meniscus of patients undergoing hip and knee replacement surgery(hip and knee joint development are normal)in the Department of Joint Surgery of the First Affiliated Hospital of Dalian Medical University from September 2015 to December 2022 were obtained,all patients signed the informed consent form for the biobank of the First Affiliated Hospital of Dalian Medical University.The collected experimental samples were placed in the ZQ-990 A Dongguan Smart Universal Tensile Pressure Testing Machine to perform tensile experiments and compression experiments respectively,and the elastic modulus of the experimental samples obtained was obtained by linear regression analysis method,and the compressive strength was calculated by substituting the calculation formula.SPSS 25.0 software and Graph Pad Prism 8 software were used to perform the following statistical analysis and graphing: independent sample t-test was used to compare whether there was a difference in the age of meniscus and acetabular labral donors;Chi-square test was used to analyze whether there was a difference in the sex ratio composition of meniscus and acetabular labral donors.Similarly,the independent sample t-test was used to compare the differences in elastic modulus values and compressive strength values between the lips of the meniscus and acetabular labrum.Results: The presence of the knee meniscus increases the contact area of the tibiofemoral joint,reduces the contact pressure in the tibiofemoral joint,exerts its weight-bearing transmission function,and better maintains the stability of the knee joint;The acetabular labrum mainly plays a sealing function in the hip joint,maintains the negative pressure state in the hip joint,forms the "suction seal" effect,and increases the stability of the hip joint.According to the "stress-strain" curves of the meniscus and acetabular labrum during the tensile experiment,it can be seen that the meniscus and the acetabular labrum show a similar change trend,and the average tensile elastic modulus of the meniscus is 59.76±5.73 MPa,and the average tensile elastic modulus of the acetabular labrum is 13.48±1.99 MPa.According to the "stress-strain" curves of meniscus and acetabular labrum during compression experiments,the meniscus and acetabular labrum also showed similar change trends,and the average compression strength of meniscus was calculated to be 100.43±10.53N/mm,and the average compression strength of acetabular labrum was 20.32±2.81N/mm.There were no significant differences in the age and sex ratio composition of meniscus and acetabular lip donors,and there were significant differences in the elastic modulus values and compressive strength values between meniscus and acetabular labral lips,the average tensile strength of meniscus was 4.4 times that of acetabular labrum,and the average compressive strength of meniscus was 4.9 times that of acetabular labrum.Conclusion: Our biomechanical comparative analysis results show that the "stressstrain" curves of compressive and tensile properties of meniscus and acetabular labral are similar,but there are significant differences in compressive and tensile strength,and the tensile and compressive strength of acetabular labrum are significantly lower than that of meniscus.Therefore,the acetabular labrum is prone to injury when FAI patients have femoral acetabular impingement.Part 2 Study about range of labral tear in FAI patients based on the three-dimensional reconstruction model of the hip jointBackground: Acetabular labral injury is the primary secondary lesion of femoral acetabular impingement(FAI)and a major source of hip pain.This part of the study will establish a three-dimensional geometric model of hip joint in FAI patients,use three-dimensional geometric models to simulate hip joint movement,study the relationship between hip joint movement angle and labral impact range,and statistically calculate the range of acetabular labral injury in FAI patients,provide experimental evidence for the mechanism and extent of labral injury in FAI patients,and provide reference for the clinical treatment of labral injury.Objective: The range of motion of normal adults was obtained by infrared threedimensional motion capture analysis system,and the three-dimensional geometric model of hip joint of FAI patients was reconstructed by using the imaging data of different types of FAI patients,and the changes of hip joint movement angle and the distance between the femoral head and neck junction area and the acetabular margin during the impact of different types of FAI patients were recorded,and the relationship between hip joint angle and labral impact range was studied.Methods: A total of 10 healthy students from the Department of Physical Education in Dalian University of Technology were selected.General information such as gender,age,height,and weight were collected,and normal adult hip range of motion was obtained and recorded under the Vicon infrared 3D motion capture analysis system.A three-dimensional geometric model of hip joint of FAI patients was established,and the hip joint activity of FAI patients was simulated in the three-dimensional geometric model with reference to the physiological range of hip joint in the previous stage,and the hip joint movement angle and the distance between the femoral head and neck junction area and the acetabular margin were recorded during the impact process,and the extent of acetabular labrum injury was evaluated,and the relationship between hip motion angle and labrum impact range was studied.SPSS 25.0 software was used for statistical analysis,and univariate ANOVA was used to compare whether there was a statistical difference in the angle of activity of femur-acetabular impingement in different types of FAI patients,where the P< 0.05.Results: There were 5 male volunteers,with an average age of 20±1.4 years,an average height of 172±3.2cm,and an average weight of 67±4.1kg.There were 5 female cases,with an average age of 20±1.2 years,an average height of 169±2.9 cm,and an average weight of 62±5.3kg.The analysis of hip motion by Vicon light capture showed that the range of motion of normal adult hip joint was as follows: flexion angle 0°-124.13±5.83°,extension angle 0°-18.41±3.32°,external rotation angle 0°-41.80±3.53°,internal rotation angle 0°-32.92±3.12°.In patients with CAM deformity FAI,femur-acetabular impingement occurs when the hip joint is rotated internally and externally 0° and the flexion angle is greater than 112°±2.6°;The hip joint flexion is 100°,internal rotation is 0°-13.5±2.4°,and the distance between the femoral head and neck junction area and the acetabular margin is gradually shortened until it is just the time to produce a femuracetabular impact;the area of labral injury ranges from 11 to 3 points.In patients with Pincer deformity FAI,femur-acetabular impingement occurs when the hip joint is rotated internally and externally by 0° and the flexion angle is greater than 113°±2.6°;the hip joint flexion is 100°,internal rotation is 0°-14±2.1°,and the distance between the femoral head and neck junction area and the acetabular margin is gradually shortened until it is just the time to produce a femur-acetabular impact;the area of labral injury ranges from 11 to 2 points.In patients with mixed deformity FAI,FemurAcetabular Impingement occurs when the hip joint is rotated internally and externally 0° and the flexion angle is greater than 105.5°±3.7°;the hip joint flexion is 100°,internal rotation is 0°-8±2.6°,and the distance between the femoral head and neck junction and the acetabular margin is gradually shortened until the femur-acetabular impact is just produced;the area of labral injury ranges from 10 to 3 points.The results of one-way ANOVA showed that there was a statistically significant difference in the minimum flexion angle of the hip joint during femoral acetabular impingement with hip internal and external rotation of 0° compared with mixed deformity FAI patients(P<0.05),and the minimum flexion angle of hip joint when femoral acetabular impact occurred by hip internal and external rotation 0° in patients with mixed deformity FAI was smaller than that of CAM deformity and Pincer deformity FAI patients.Compared with patients with mixed deformity FAI,there was a statistically significant difference in the minimum internal rotation angle of the hip joint at femoral acetabular impact with 100° flexion(P<0.05),and the minimum internal rotation angle of the hip joint at femoral acetabular impact at 100° in patients with mixed deformity FAI was smaller than that in patients with mixed deformity FAI with hip flexion 100° and femoral acetabular impact.Conclusion: The range of hip motion angle in normal adults is: flexion angle 0°-124.13±5.83°,posterior extension angle 0°-18.41±3.32°,external rotation angle 0°-41.80±3.53°,internal rotation angle 0°-32.92±3.12°;Compared with patients with Cam deformity and Pincer malformation FAI,patients with mixed deformity FAI can produce femoral acetabular impingement at a smaller angle of hip motion,and the scope of labrum injury is also greater than that of Cam malformation and Pincer malformation FAI patients. |
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