OBJECTIVE: To measure and analyze the relationships among the posterior tibial slope (PTS), meniscal slope (MS), and meniscus posterior horn thickness (MPHT) of the medial and lateral tibial plateau in healthy people and patients with anteromedial osteoarthritis (AMOA) in Heilongjiang province, so as to provide reference basis for appropriate tibial osteotomy and prosthesis placement angles in knee joint surgeries. METHODS: A retrospective collection of imaging data from knee joint MRI examinations conducted prior to AMOA for various reasons was performed. A total of 103 healthy individuals (healthy group) and 30 AMOA patients (AMOA group) were included. There was no significant difference in the gender composition ratio, side, and body mass index between the two groups ( P>0.05); however, the comparison of ages between the two groups showed a significant difference ( P<0.05). The collected DICOM format image data was imported into the RadiAnt DICOM Viewer software and measured the medial PTS (MPTS), lateral PTS (LPTS), medial MS (MMS), lateral MS (LMS), medial MPHT (MMPHT), and lateral MPHT (LMPHT) with standard methods. The differences of the above indexes between the two groups and between different genders and sides in the two groups were compared, and Pearson correlation analysis was carried out. At the same time, the measured data of healthy group were compared with the relevant literature reported in the past. RESULTS: Compared to the healthy group, the AMOA group exhibited significantly smaller MPTS and LPTS, as well as significantly greater MMPHT and LMPHT, with significant differences ( P<0.05). However, there was no significant difference in the MMS and LMS between the two groups ( P>0.05). The differences in various indicators between genders and sides within the two groups were not significant ( P>0.05). The correlation analysis and regression curves indicated that both MPTS and LPTS in the two groups were positively correlated with their respective ipsilateral MS and MPHT ( P<0.05); as PTS increased, the rate of increase in MS and MPHT tend to plateau. Compared to previous related studies, the MPTS and LPTS measured in healthy group were comparable to those of the Turkish population, exhibiting smaller values than those reported in other studies, while MMS and LMS were relatively larger, and MMPHT and LMPHT were smaller. CONCLUSION In healthy people and AMOA patients in Heilongjiang province, PTS has great individual differences, but there is no significant individual difference in MS. MPHT can play a certain role in retroversion compensation, and its thickness increase may be used as one of the indicators to predict the progression of AMOA. The above factors should be taken into account when UKA is performed, and the posterior tilt angle of tibial osteotomy should be set reasonably after preoperative examination and evaluation.
Humans ; Osteoarthritis, Knee/surgery* ; Retrospective Studies ; Tibia/pathology* ; Male ; Female ; Adult ; Menisci, Tibial/anatomy & histology* ; China ; Knee Joint/pathology* ; Magnetic Resonance Imaging ; Middle Aged ; Aged ; Osteotomy

OBJECTIVE: To investigate the impact of bone mass and volume of low-density zones beneath the tibial plateau on the maximum von Mises stresses experienced by the cartilage and meniscus in the knee joint. METHODS: The study included one healthy adult volunteer, from whom CT scans were obtained, and one patient diagnosed with knee osteoarthrisis (KOA), for whom X-ray films were acquired. A static model of the knee joint featuring a low-density zone was established based on a normal knee model. In the finite element analysis, axial loads of 1 000 N and 1 800 N were applied to the weight-bearing region of the upper surface of the femoral head for model validation and subsequent finite element studies, respectively. The maximum von Mises stresses in the femoral cartilage, as well as the medial and lateral tibial cartilage and menisci, were observed, and the stress percentage of the medial and lateral components were concurrently analyzed. Additionally, HE staining, as well as alkaline magenta staining, were performed on the pathological specimens of patients with KOA in various low-density regions. RESULTS: The results of model validation indicated that the model was consistent with normal anatomical structures and correlated with previous calculations documented in the literature. Static analysis revealed that the maximum von Mises stress in the medial component of the normal knee was the lowest and increased with the advancement of the hypointensity zone. In contrast, the lateral component exhibited an opposing trend, with the maximum von Mises stress in the lateral component being the highest and decreasing as the hypointensity zone progressed. Additionally, the medial component experienced an increasing proportion of stress within the overall knee joint. HE staining demonstrated that the chondrocyte layer progressively deteriorated and may even disappear as the hypointensity zone expanded. Furthermore, alkaline magenta staining indicated that the severity of microfractures in the trabecular bone increased concurrently with the expansion of the hypointensity zone. CONCLUSION The presence of subtalar plateau low-density zone may aggravate joint degeneration. In clinical practice, it is necessary to pay attention to the changes in the subtalar plateau low-density zone and actively take effective measures to strengthen the bone status of the subtalar plateau low-density zone and restore the complete biomechanical function of the knee joint, in order to slow down or reverse the progression of osteoarthritis.
Humans ; Finite Element Analysis ; Knee Joint/physiology* ; Tibia/anatomy & histology* ; Cartilage, Articular/physiology* ; Menisci, Tibial/physiopathology* ; Tomography, X-Ray Computed ; Osteoarthritis, Knee/diagnostic imaging* ; Weight-Bearing ; Bone Density ; Adult ; Stress, Mechanical ; Male ; Middle Aged ; Biomechanical Phenomena ; Female

OBJECTIVE: To establish a finite element model of the knee joint based on coronal plane alignment of the knee (CPAK) typing method, and analyze the biomechanical characteristics of different types of knee joints. METHODS: The finite element models of the knee joint were established based on CT scan data of 6 healthy volunteers. There were 5 males and 1 female with an average age of 24.2 years (range, 23-25 years). There were 3 left knees and 3 right knees. According to the CPAK typing method, the knees were rated as types Ⅰ to Ⅵ. Under the same material properties, boundary conditions, and axial loading, biomechanical simulations were performed on the finite element model of the knee joint. Based on the Von Mises stress nephogram and displacement nephogram, the peak stresses of the meniscus, femoral cartilage, and tibial cartilage, and the displacement of the meniscus were compared among different types of knee joints. RESULTS: The constructed finite element model of the knee joint was verified to be effective, and the stress and displacement results were consistent with previous literature. Under the axial load of 1 000 N, the stress nephogram showed that the stress distribution of the medial and lateral meniscus and tibial cartilage of CPAK type Ⅲ knee joint was the most uneven. The peak stresses of the lateral meniscus and tibial cartilage were 9.969 6 MPa and 2.602 7 MPa, which were 173% and 165% of the medial side, respectively. The difference of peak stress between the medial and lateral femoral cartilage was the largest in type Ⅳ knee joint, and the medial was 221% of the lateral. The displacement nephogram showed that the displacement of the medial meniscus was greater than that of the lateral meniscus except for types Ⅲ and Ⅵ knee joints. The difference between medial and lateral meniscus displacement of type Ⅲ knee joint was the largest, the lateral was 170% of the medial. CONCLUSION In the same type of joint line obliquity (JLO), the medial and lateral stress distribution of the knee was more uniform in varus and neutral positions than in valgus position. At the same time, the distal vertex of JLO subgroup can help to reduce the uneven medial and lateral stress distribution of varus knee, but increase the uneven distribution of valgus knee.
Humans ; Finite Element Analysis ; Knee Joint/diagnostic imaging* ; Female ; Biomechanical Phenomena ; Adult ; Male ; Young Adult ; Stress, Mechanical ; Weight-Bearing/physiology* ; Computer Simulation ; Tomography, X-Ray Computed/methods* ; Cartilage, Articular/physiology* ; Range of Motion, Articular ; Menisci, Tibial/anatomy & histology* ; Tibia/anatomy & histology* ; Meniscus/diagnostic imaging* ; Femur/diagnostic imaging* ; Models, Biological

Meniscal injury is one of the most common injuries to the knee. The menisci are important for normal knee function. And loss of a meniscus increases the risk of subsequent development of degenerative changes in the knee. Now there are different techniques available for meniscal injury. These techniques include expectant treatment, meniscectomy, meniscal repair, meniscal replacement, and meniscal tissue engineering. Expectant treatment is the appropriate treatment for minor tears of the menisci. Meniscectomy being favored at the beginning is now obsolete. Meniscus repair has become a standard procedure. Meniscal replacement and tissue engineering are used to deal with considerable meniscal injuries. The purpose of this paper is to provide current knowledge regarding the anatomy and function of the menisci, incidence, aetiology, symptoms, signs, investigations and treatments of meniscal injury.
Animals ; Humans ; Knee Injuries ; surgery ; Menisci, Tibial ; anatomy & histology ; physiology ; Tibial Meniscus Injuries ; Tissue Engineering

BACKGROUNDAllograft meniscal transplantation is an increasingly popular treatment option for the symptomatic young patients with meniscus deficiency. However, many questions still surround it. In this research, we studied the anatomical location and histological structure of human meniscal horn bony insertions and to observe the anatomical morphology and histomorphology of peri-meniscal attachments based on meniscal allograft transplantation.

METHODSTwenty-two fresh-frozen adult cadaver knees were dissected. The locations of meniscal anterior and posterior horn bony insertions to tibia were measured. The anatomical morphology of peri-meniscal attachments was observed and the histological structure of meniscal horn bony insertions and peri-meniscal attachment were studied by HE staining.

RESULTSThe anterior horn bony insertion of medial meniscus was (9.19 +/- 1.83) mm inferior to the corresponding anterior border of tibial plateau, and (7.81 +/- 2.25) mm lateral to the axial line of the medial intercondylar eminence. The posterior horn bony insertion of medial meniscus was in the posterior intercondylar fossa of tibia, located between the anterior fibers of the posterior cruciate ligament (PCL) tibial insertion and anterior border of the tibial posterior intercondylar fossa, and was (5.05 +/- 1.18) mm lateral to the axial line of the medial intercondylar eminence. The distance between anterior and posterior horn bony insertions of the lateral meniscus was (13.68 +/- 2.19) mm. Anterior horn bony insertion of the lateral meniscus was (3.99 +/- 1.27) mm medial to the axial line of the lateral intercondylar eminence, and the posterior horn bony insertion of the lateral meniscus was (5.80 +/- 1.36) mm medial to the axial line of the lateral intercondylar eminence. Except for the meniscal horn bony insertions, which is the typical enthesis, we call the attachment of the other parts of menisci as 'peri-meniscal attachment'. The morphological and histological study showed that the main peri-meniscal attachment was the meniscotibial ligament, through which the meniscus attached to the tibia with enthesis structure, and there was only loose connective tissue between menisci and capsule.

CONCLUSIONSIn meniscal allograft transplantation, the traditional meniscal size-matching method which take medial and lateral intercondylar eminences as references is not as accurate as expected. Attention should be taken to locate both anterior and posterior horn tunnels of medial meniscal allograft inferior to the tibia plateau, and to locate anterior and posterior horn tunnels of lateral meniscus close enough (mean 13.68 mm). The best way to reconstruct the peri-meniscal attachment is to suture the allograft to the preserved outer remnant of the original meniscus.

Adult ; Anterior Cruciate Ligament ; anatomy & histology ; cytology ; Cadaver ; Female ; Humans ; Male ; Menisci, Tibial ; anatomy & histology ; cytology ; transplantation ; Transplantation, Homologous