| Objective:To observe the anatomy of the proximal tibiofibular joint(PTFJ),and explore the relationship between PTFJ-related anatomical parameters and the occurrence and development of knee osteoarthritis(KOA)in the medial compartment of the knee joint.Methods:Part I:(1)20(unpaired)human knee joint specimens were used to study.Anterior proximal tibiofibular ligament(APTFL)and posterior tibiofibular ligament(PPTFL)were dissected.The number of ligaments,the length,width,thickness of each ligament and the distance from the ligament insertion to anatomical landmarks(Gerdy’s tubercle,lateral tibial plateau,fibular styloid)was counted.(2)The type of joint,joint inclination angle,articular surface area,articular cartilage thickness,and articular surface shape of the PTFJ were measured and statistically.(3)The posterolateral complex(PLC)was dissected and observed.The presence rate of each ligament in the PLC,and indicators such as length,width,and thickness were measured,and the relationship between PLC and PTFJ was explored.Part II:(1)104 patients(KOA group)which diagnosed with KOA in the Orthopaedic clinic of Affiliated Hospital of Qingdao University from September 2019 to September 2021 and 97 healthy volunteers(healthy group)matched in age,sex and side were analyzed.Basic data of all subjects,including gender,age,side and BMI were collected.PTFJ-related anatomical parameters PTFJ inclination,PTFJ height,PTFJ declination,and PTFJ lateral position were measured using three-dimensional measurements in 201 subjects.The basic data and PTFJ anatomical parameters of the KOA group and the healthy group were compared.The indexes with significant differences were incorporated into the logistic regression,and the independent risk factors affecting the KOA disease were analyzed.(2)KOA patients were divided into mild-to-moderate group(K-L I-II grade)and severe group(K-L III-IV grade)according to K-L classification.Basic data and PTFJ anatomical parameters were compared between two groups.Indicators with significant differences were incorporated into logistic regression to analyze independent risk factors affecting the severity of KOA.Results:Part I:(1)At most five ligaments were found in APTFL,from top to bottom,they were superior bundle,middle 1 bundle,middle 2 bundle,oblique bundle and inferior bundle,and their presence rates were 100%,85%,70%,80%,and 40%.In the APTFL,the length of each bundle of ligaments ranged from(8.65-32.88)mm,the width was(2.25-10.41)mm,and the thickness was(0.67-2.44)mm.The superior bundle was the longest,widest,and thickest in the APTFL ligaments,which played a vital role in APTFL.The superior bundle,middle1 bundle,middle 2 bundle,and oblique bundle all originated from around the Gerdy’s tubercle,were located outside and below the Gerdy’s tubercle(1.11-10.52)mm,and ended in the medial and inferior fibular styloid of(5.20-34.50)mm.The inferior bundle was slightly inferior to the other 4 bundles of ligaments,connecting the fibula and tibia at the level of the fibular neck.At most three bundles of ligaments were found in PPTFL.They were superior,middle and inferior bundle,and their presence rates were 100%,100% and45%,respectively.In PPTFL,each bundle of ligaments ranged from(5.46-15.19)mm in length,(2.74-13.32)mm in width,and(0.62-2.53)mm in thickness.The middle bundle was the longest,widest,and thickest ligament in the PPTFL,and it was an important stable structure behind the PTFJ.The ligament originated from the posterior and inferior(3.28-42.77)mm of the lateral tibial plateau and inserted into the medial and inferior(0.62-2.53)mm of the fibular styloid.(2)The trochoid type was the most common joint type when classified by the shape of the joint.And the oblique joint was the most common type when classified by the joint inclination angle.The average joint inclination angle was(32.36±7.05)*.The most common shape of the tibial articular surface was circular,and the most common shape of the fibular articular surface was triangular.The cartilage area and thickness of the articular surface of the tibia were greater than those of the articular surface of the fibula(P<0.05).(3)The presence rate of lateral collateral ligament(LCL)was 100%,the length was(58.73±5.65)mm,and the width was(5.78±3.23)mm,and the thickness was(2.21±0.58)mm.The presence rate of popliteus tendon(PT)was 100%,the length was(39.72±3.22)mm,the width was(8.42±2.20)mm,and the thickness was(4.22±1.33)mm.The presence rate of Popliteofibular ligament(PFL)was 100%,the length of the anterior edge was(9.98±2.21)mm,the length of the posterior edge was(7.43±1.45)mm,the width was(5.44±2.21)mm,and the thickness was(2.01±0.89)mm.The presence rate of fabellofibular ligament(FEL)was 40% and the length was(37.58±7.82)mm.The arcuate ligament(AL)was present in 100% of cases.The PCL provided additional stability to the PTFL.Part II:(1)PTFJ inclination angle,PTFJ height and PTFJ declination were statistically different in univariate analysis between KOA group and healthy group.Logistic regression analysis showed that PTFJ inclination angle(OR=0.917,P=0.000),PTFJ height(OR=855,P=0.000)and PTFJ declination(OR=1.062,P=0.027)were independent risk factors for KOA.(2)The BMI,PTFJ inclination angle,PTFJ declination angle,PTFJ height and PTFJ lateral position were significantly different in the univariate analysis between the mildmoderate group and the severe group(P<0.1).The logistic results showed that the BMI(OR=1.161,P=0.019),PTFJ inclination angle(OR=0.905,P=0.000),and PTFJ height(OR=0.793,P=0.000)were independent risk factors for the severity of KOA.Conclusion:(1)The basic parameters and positions of the PTFJ ligament were discussed,which provided a theoretical basis for the diagnosis of PTFJ ligament injury and PTFJ ligament reconstruction.(2)The PTFJ had great variability in joint morphology and articular surface morphology,and this variability may lead to differences in PTFJ biomechanics.(3)The PLC was an important structure of the posterolateral knee joint,which was closely related to the PTFJ and can provide additional stability to the PTFJ.(4)Lower PTFJ inclination,lower PTFJ height,and higher PTFJ declination were risk factors for KOA;Lower PTFJ inclination,lower PTFJ height and higher BMI were the risk factors for severe KOA.For people with such characteristics,regular physical examinations should be taken,and measures should be taken to prevent or delay the occurrence and development of KOA. |
