| Objective:Knee joint is the largest and most complex joint in the human body.Knee joint injury is an essential point and difficulties in clinical work.There is highly probable that knee joint injury will progress to knee osteoarthritis(KOA)and cause great distress to patients if it is not cured for a long time.Therefore,scholars have come a long way of research in anatomy,mechanics,treatment and other aspects,aiming at further understanding of knee joint injury.Among them,the study of stress characteristics of the knee joint was of enormous significance for understanding the mechanism of knee joint injury and further treatment of KOA.Cruciate ligament is an important part of the stabilization of the knee joint movement.A correct understanding of the anatomical information of the attachment site of the cruciate ligament was of particular significance to the study of the overall stress characteristics of the knee joint.Meanwhile,some scholars speculated that the posterolateral stress characteristics of the knee joint also play an important role in understanding the overall stability of the knee joint.In the posterolateral structure of the knee joint,there was some unclear anatomical information in the study of the mechanical properties of the popliteal muscle-tendon complex(PMTC)and between the fibula and the lateral tibial plateau.P45 plastination technique,which can be applied to fully show the internal structure of specimens.Because of its extraordinary properties,the accurate anatomy structure of the specimen could be found in a large scale.In this study,with the combined application of gross anatomy and P45 plastination technology,the formalin-soaked specimens of adult human knee joint were taken as the object,and the following studies were performed.(1)P45 plastination technology was used to analyze the trabecula bone architecture characteristics of the cruciate ligament attachment.(2)In the popliteal muscle tendon complex,the adjacent relationship between the popliteal muscle and the surrounding tissue was studied.The anatomical information of the PMTC was enriched,and provided an anatomical basis for further revealing the role of popliteal muscle in stabilizing the knee joint.(3)Structural characteristics of the trabecula bone of the lateral tibial plateau and its relationship with fibula were analyzed.This study provides an anatomical basis for the clinical treatment of KOA and provides new vision on the clinical understanding of the pathogenesis of KOA.Methods:(1)Formalin-soaked specimens of 27 adult knee joints which were not abnormal in imaging examination were selected for P45 plastination technology.(2)Three researchers independently observed 27 sets of knee joint sections and recorded and analyzed the characteristics of trabecula bone architecture of cruciate ligament at the attachment sites of the femur and tibia.(3)The gross anatomy of 7 cases of adult knee joint soaked with formalin and 9 cases of sagittal P45 plasticized slice of the knee joint were used to observe and analyze the relationship between popliteal muscle and posterior cruciate ligament(PCL),posterior laminofemoral ligament(PMFL),lateral meniscus and articular capsule(AC).(4)P45 slices of 20 cases of the knee joint were used to observe and analyze the relationship between the characteristics of trabecula bone architecture of lateral tibial plateau and fibula.Results:(1)The results of the P45 plasticized slice of the cruciate ligament of the knee joint showed the anterior cruciate ligament thickens the bone cortex at the attachment of the femur.In the medial wall of the lateral condyle shown thickening of the trabeculae and are diffusely radiodense extend into the medullary cavity.The bone cortex of the anterior cruciate ligament was thickened at the attachment of the tibia,and the bone trabeculae of the anterior part of the anterior cruciate ligament were thickened and arranged in parallel on the extension line of the ligament.While on the deep of the posterior cortex of the attachment,several bone trabeculae were thickened and arranged in parallel,which the direction was perpendicular to the direction of ligament fibers.The bone cortex of the posterior cruciate ligament was thickens at the attachment of the femur.At the lateral wall of the medial condyle,the bone trabeculae was thickens and dense,extending radially to the deep.Cortical thickening at the tibial attachment of the posterior cruciate ligament.The longitudinal parallel arrangement of thick bone trabeculae could be obversed on the deep surface of the posterior part of the bone cortex at the attachment site,which spreads to the epiphyseal line.The weak area of the cortex could be obversed from the posterior inferior part of the ligament attachment to the epiphyseal line.(2)The gross anatomy of the posterior part of the knee joint showed when the popliteal muscle walked from the bottom of the popliteal fossa to the posterior edge of the platform of the lateral condyle of the tibia,the popliteal muscle obliquely inserted into the articular capsule and moved a tendon.At the tendon-muscle transition,from medial to lateral,the popliteal muscle separately sends out dense connective tissue to connect with the posterior cruciate ligament,dense fiber bundles to connect with the PMFL,and dense connective tissue band to connect the lateral meniscus.The results of the P45 section showed that behind the intercondylar eminence attachment area of the posterior cruciate ligament,the popliteal muscle fascia bypassed the posterior edge of the tibial plateau,moved forward,integrated into the posterior cruciate ligament and participated in the formation of the posterior cruciate ligament.Near the posterior edge of the lateral tibial plateau,the popliteal tendon penetrates the articular capsule and sends 2 dense fibers upward:(1)The ventral fiber bundle bypasses the posterior edge of the tibial plateau and moves forward to connect with the lateral meniscus.(2)The dorsal fibers ascend directly into the articular capsule.(3)The results of the P45 slice of upper of tibia and fibula showed that the distribution of bone trabeculae in lateral condyle of tibial plateau was nonuniform.Longitudinal thick bone trabeculae could be found in the projection area of the articular surface,showing parallel cluster distribution,descending through the epiphyseal line to reach the epiphyseal cortical abduction slope.In the lateral condyle above the tibiofibular joint,the bone trabeculae were sparse,and no obvious longitudinal trabeculae was found.In the lateral condyle of tibia and fibular head,a tiny bone trabeculae distributed perpendicular to the articular surface of tibia and fibula could be found.Meanwhile,the posterolateral metaphyseal of the tibia,through the tibiofibular joint,forms an arch beam structure with the fibula,and the cortical slope of the tibia,which carries the longitudinal thick bone trabeculae,was located at the top of the arch beam.Conclusion :(1)The bone cortex at the attachment of the cruciate ligament was slightly thicker than that around,and the bone trabeculae on the deep of the bone cortex were thick and dense.The trabeculae bone at the attachment end of the femur was mainly radially enhanced,while the tibial attachment was mainly enhanced in the direction of the extension line and vertical line of the ligament.The arrangement of the trabeculae bone of the cruciate ligament at the attachment of the tibia and femur was different,reflecting the difference in the form of stress at the attachment.(2)There was a dense connective tissue connection between the popliteal muscle and the posterior cruciate ligament,and the popliteal fascia was involved in the composition of the posterior cruciate ligament.It was shown a dense fiber bundle connection between the popliteal muscle and the posterior laminofemoral ligament.Existence of a dense connective tissue band connection between the popliteal muscle and the lateral meniscus.The connection between the popliteal muscle and the above three structures mainly occured at the tendon-muscle migration,when the popliteal muscle penetrates the articular capsule.After the popliteal muscle penetrated the articular capsule,it sent out two bundles of fibers in the abdomen and back upward to participate in the connection of the popliteal tendon complex.(3)We found a cluster of dense longitudinal thick bone trabeculae in the posteriorlateral part of the tibial plateau,which terminates in the posterior lateral cortex of the fibula and tibial shaft to form an arch beam structure,and the fibula was the mechanical fulcrum of the arch beam.This study further provides accurate anatomical information of the knee joint and provides a new vision for the clinical diagnosis and treatment of knee joint diseases,especially KOA. |
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