Architecture Of The Cancellous Bone In Human Proximal Tibia Based On The P45 Sectional Plastinated Specimen

Objective:Tibial plateau is consisted of the medial and lateral condyles of the tibia and intercondylar eminence.Cancellous as an important component of the proximal tibia,is widely distributed inside the thin contex.There is a certain regularity in distribution of trabecula in the proximal tibia.Certain typical differences in the arrangement and configuration of the trabecular bone can be recognized,the trabeculae were usually arranged different in epiphyseal and metaphyseal.There are certain limitations to the current study,due to lack of effective comprehensive observation of complete information the trabeculae orientation of each site.Wolff’s law suggested that trabecular patterns appeared to be aligned along principal stress directions.When the stress changes,the trabecular bone adapted to mechanical demands,it will be a mechanically optimal structure.Knee joint injury and inflammation are common,which is the focus and difficulty of clinical diagnosis and treatment.Therefore,It is necessary to obtain the structural information of trabecular bone.However,CT and MRI can only provide density non-uniform of distribution,the sample size of micro-CT is small,it is difficult to observe the trabecular morphology of complete bone.due to the limitation of resolution,the image resolution of these in vivo techniques is still limited,which provides the best resolution longer than thickness of individual trabeculae and thus cannot reliably observe trabecular architecture.P45 is a new polyester sectional plastination technique allows an observation of trabecular bone structure on a large area with higher clarity.The study provides an anatomical basis for biomechanical of knee joint.Materials and methods:27 cases of formalin-fixed adult knee specimens were sectioned in coronal,sagittal and horizontal planes respectively using the P45 sectional plastination technique.The trabecular architecture of the proximal tibia was observed and analyzed in cross-section and the results were recorded by photography.Results:Trabecular bone architecture were observed in the epiphysis and metaphysis of the proximal tibia.Trabeculae were unevenly arranged in the epiphysis and different pattens of the trabecular architecture were distinguished.In the medial and lateral condyles,under the articular cartilage where directly contact with the femoral condyle,the dense and thick trabeculae are arranged longitudinally and extended to pass through the epiphyseal line.And near the articular surface these trabeculae are connected by thick trabecular beams mainly in sagittal direction.Whereas,beneath the thick peripheral portion of meniscus the cancellous bone is primarily built with reticular trabeculae or sparse longitudinal trabeculae.However,in intercondylar eminence the spongy bone is formed by larger polygonal grid trabeculae.Near the attaching areas of the iliotibial tract,tibial collateral ligament,anterior and posterior cruciate ligament,and patellar ligament,the cancellous bone is locally reinforced with the patchy trabeculae,dense radiated trabeculae,or two orthotropic trabecular bands.And in peripheral portion of the tibia metaphysis,thick and dense longitudinal trabeculae are constructed on the medial,lateral and posterior cortical slopes and connected by fine beams,and these longitudinal trabeculae are continued with the trabeculae of the epiphysis at the epiphyseal line.In the meanwhile,the central portion of the tibia metaphysis is consist of fine arcuate trabeculae,which from the anterior and posterior cortices respectively are intersected sparsely to form trusses over the medullary cavity.Conclusion:The soft structures of knee joint,including the articular cartilage,menisci,and ligaments,are important land marks for location of different styles of the cancellous architecture.Under the articular cartilage surrounded by the medial or lateral meniscus,the cancellous bone is formed by thick and dense trabecular bands,which longitudinally run in epiphysis and then pass through the epiphyseal line to terminate on slanted cortex of the metaphysis.In the intercondylar eminence,the trabeculae are arranged basically in network,and in the central portion of the tibia metaphysis,cancellous bone is consist of fine arcuate trabeculae.Near the attaching areas of the knee joint ligaments,the cancellous bone is locally reinforced with the patchy trabeculae,dense radiated trabeculae,or two orthotropic trabecular bands.