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

PURPOSE: The purpose of this study was to investigate the effects of transplantation of an in vitro-generated, scaffold-free, tissue-engineered cartilage tissue analogue (CTA) using a suspension chondrocyte culture in a rabbit growth-arrest model. MATERIALS AND METHODS: We harvested cartilage cells from the articular cartilage of the joints of white rabbits and made a CTA using a suspension culture of 2x107 cells/mL. An animal growth plate defect model was made on the medial side of the proximal tibial growth plate of both tibias of 6-week-old New Zealand white rabbits (n=10). The allogenic CTA was then transplanted onto the right proximal tibial defect. As a control, no implantation was performed on the left-side defect. Plain radiographs and the medial proximal tibial angle were obtained at 1-week intervals for evaluation of bone bridge formation and the degree of angular deformity until postoperative week 6. We performed a histological evaluation using hematoxylin-eosin and Alcian blue staining at postoperative weeks 4 and 6. RESULTS: Radiologic study revealed a median medial proximal tibial angle of 59.0degrees in the control group and 80.0degrees in the CTA group at 6 weeks. In the control group, statistically significant angular deformities were seen 3 weeks after transplantation (p<0.05). On histological examination, the transplanted CTA was maintained in the CTA group at 4 and 6 weeks postoperative. Bone bridge formation was observed in the control group. CONCLUSION: In this study, CTA transplantation minimized deformity in the rabbit growth plate injury model, probably via the attenuation of bone bridge formation.
Animals ; *Bone Transplantation ; Cartilage/anatomy & histology ; Cell Culture Techniques ; Cells, Cultured ; Chondrocytes/*cytology/transplantation ; Growth Plate/anatomy & histology/*surgery ; *Mesenchymal Stem Cell Transplantation ; Rabbits ; Tibia/*surgery ; Tissue Engineering ; Transplantation, Autologous/methods ; Transplantation, Homologous

OBJECTIVETo observe the effects of warm needling moxibustion on body mass, knee cartilage andmorphology in rats with knee osteoarthritis (KOA).

METHODSForty SD rats were randomly divided into a normalgroup, a model group, a medication group and a warm needling group, 10 rats in each one. Except the normalgroup, the rats in the remaining three groups were injected with papain to establish the model of KOA. After themodeling, rats in the model group did not receive any treatment; rats in the warm needling group were treated withwarm needling moxibustion at bilateral "Xiqian"; rats in the medication group were treated with intragastric administration of meloxicam; rats in the normal group were treated with 0. 9% NaCl solution (identical dose as medication group) and immobilized as the warm needling group. The treatment was given once a day for consecutive20 days. The body mass, scale of knee cartilage and morphological changes were observed in each group after'treatment.

RESULTSThe increasing of body mass in the medication group and warm needling group was faster than!that in the model group, but slower than that in the normal group (all P<0. 05); the difference between medication group and warm needling group was not statistically significant (P>0. 05). The scale of knee cartilage in thewarm needling group and medication group was significantly lower than that in the model group (both P<0. 05),while the scale in the warm needling group was lower than that in the medication group (P<. 05). Regarding theknee morphology under micro-CT, the relief of knee degeneration and improvement of knee recovery in the warm needlinggroup were superior to those in the medication group.

CONCLUSIONThe warm needling moxibustion could effectively reduce the knee pain, improve the recovery of knee cartilage, which is a safe and effective treatment.

Acupuncture Points ; Animals ; Cartilage ; anatomy & histology ; Disease Models, Animal ; Humans ; Knee Joint ; anatomy & histology ; Male ; Moxibustion ; Osteoarthritis, Knee ; therapy ; Rats ; Rats, Sprague-Dawley ; Treatment Outcome

OBJECTIVE: There are many scaffold materials of repairing nasal alar cartilage defects. Auricuiar cartilage was used extensively in terms of its abundant tissues, good elasticity, little donor-site malformation, good plasticity etc. The authors dissected auricular cartilage and nasal alar cartilage, measured cartilage's morphous data and found some similar territories with nasal alar cartilage in the structure of auricular cartilage. METHOD: An anatomical study was performed using 10 adult cadavers acquired through Plastic Surgery Hospital, Peking Union Medical College, Beijing, China. Seven male and three female cadav-ers were included in the study. Harvest 20 auricular cartilage specimens and 20 nasal alar cartilage specimens. Then, Computed Tomography Scan on the auricular cartilage and nasal alar cartilage were performed. The datas were imported into mimics and three-dimensional reconstructions of the auricular cartilage and nasal alar cartilage were carried on. RESULT: Parts of the auricular cartilage, such as conchal fossa, tragus, intertragic notch, and cymba of auricular concha, curs of helix and curs of helix, triangular fossa, are ana-tomically similar to nasal alar cartilage. CONCLUSION This study reports the anatomy of auricular cartilage and nasal alar cartilage, found some territories in the auricular cartilage, such as conchal fossa, tragus, intertragic notch, and cymba of auricular concha, curs of helix and curs of helix, triangular fossa, are anatomically similar to nasal alar cartilage. This research provides the anatomical basis that auricular cartilage was used to repair the nasal cartilage defect.
Adult ; Cadaver ; Ear Auricle ; anatomy & histology ; Ear Cartilage ; anatomy & histology ; Female ; Humans ; Male ; Nasal Cartilages ; anatomy & histology ; Reconstructive Surgical Procedures ; Tomography, X-Ray Computed

OBJECTIVE: Dissecting adult cadaver's tragal cartilage and researching its clinical application in ear surgery. METHOD: Dissect the bilateral tragal cartilage of 22 adult cadavers immersed in formalin (both of male and female are 11). Measure and compute the average value of the length, width, thickness and area. Summarize autologous tragal cartilage's clinical application in ear surgery. RESULT: The statistic values of male tragal cartilage were: length (22.55 ± 0.89) mm, width (19.00 ± 1.09) mm, thickness (1.04 ± 0.09) mm, and area (315.70 ± 32.57) mm2. The statistic values of female respectively were (19.36 ± 0.86) mm, (15.73 ± 0.69) mm, (0.93 ± 0.06) mm, and (229.64 ± 13.97) mm2. Tragal cartilages were utilized in 419 middle ear surgeries in my department, including tympanoplasty(type I 189 cases, type II and III 116 cases), atticotomy (65 cases), and the repair of the lateral skull base (3 cases). The postoperative effect was satisfactory. CONCLUSION Tragal cartilage is in the operation region, which is convenient to be harvested and shaped. Hence, the donor can satisfy the requirement of general ear surgery and it is suitable for widely application in ear surgery.
Adult ; Cadaver ; Cartilage ; anatomy & histology ; Ear Auricle ; anatomy & histology ; Female ; Humans ; Male ; Otologic Surgical Procedures ; Tympanoplasty

OBJECTIVETo observe the origins and insertions of Pitanguy ligament,in order to find the anatomically theoretical basis for the treatment of nasal deformity such as drooping nose, short columella, gingival show.

METHODS15 cadaveric heads fixed by 10% formalin were used. 12 specimens underwent nasal anatomic study. The skin was incised, along the nasal midline to expose the Pitanguy ligament. The origin of Pitanguy ligament and its relationship with surrounding tissue were studied. Then the Pitanguy ligament was taken out for HE staining. Longitudinal section along the ligament was observed. 3 specimens underwent harvesting of full-thickness nasal tissue from skin to periosteal membrane. Then the samples were used for HE staining to show histologic study of ligament at horizontal section.

RESULTSPitanguy ligament originates in the midline of lower third of the nasal superficial musculoaponeurotic system, extends down to the tip along the midline of the nasal dorsum and then turns backwards at the nasal tip, and runs between the medial crura of the lower lateral cartilages, inserts into the base of columella. Its muscle is connected with the orbicularis oris muscle and the depressor septi nasi muscle. HE staining showed the ligament consists of fibrous connective tissue, muscle tissue and other ingredients, but without cartilage.

CONCLUSIONSPitanguy ligament exists with complex histological composition, so its name is still controversial. Because it has multiple connection with the orbicularis oris muscle and the depressor septi nasi muscle, so cutting or shortened the Pitanguy ligament can treat deformity of nose and lip by adjustment of nasolabial angles and the nasal length.

Cadaver ; Cartilage ; anatomy & histology ; Facial Muscles ; anatomy & histology ; Humans ; Ligaments ; anatomy & histology ; Lip ; anatomy & histology ; Nasal Septum ; anatomy & histology ; Nose ; anatomy & histology ; Nose Deformities, Acquired ; pathology ; surgery ; Subcutaneous Tissue ; anatomy & histology

OBJECTIVETo investigate the T2 values and knee thickness in healthy young adults using 3.0 T magnetic resonance imaging(MRI) .

METHODSTotally 40 volunteers(18-30 years old) with body mass index between 18.5-24.0 kg/m(2) were divided into two groups(22 men and 18 women) according to their gender. Also in addition, each group was divided into two subgroups(right knee and left knee) . The T2 values and the thickness of the areas on the medial condyle of femur, the lateral condyle of femur, the medial tibial plateau, the lateral tibial plateau, and the patella of the knee cartilage were measured.

RESULTSThe T2 values and the thickness of the right and left knee cartilages showed no significant differences between men and women (P>0.05) . Also, the T2 values in the five parts of the knee cartilage also were not significantly different between men and women (P>0.05) . However, the thickness of the 5 parts of the knee cartilage significantly differed between men and women(P<0.05) .

CONCLUSIONSThe thickness of the knee cartilage may different between male and female young adults. The T2 values of the cartilage may be not affected by the gender.

Adolescent ; Adult ; Cartilage, Articular ; anatomy & histology ; Female ; Humans ; Knee Joint ; anatomy & histology ; Magnetic Resonance Imaging ; Male ; Sex Factors ; Young Adult

OBJECTIVETo observe the changes of bone histomorphometry parameters in condyle of rabbits during mandibular forward positioning.

METHODSForty rabbits with eight weeks of age were simple randomly divided into the experimental group (n = 24) and control group (n = 16).Mandibles of rabbits in the experimental groups were induced to forward position by a functional appliance.The experimental group and control group were sacrificed after 2 and 4, 8, 12 weeks.The specimens from right tempromandibular joints were processed for undemineralised sections.These sections were used for fluorescent microscopy observation and the measurement of bone histomorphometry.

RESULTSAt 8 week bone-volume fraction [(75.83 ± 1.10)%], trabecular thickness [(103.28 ± 2.89) µm], trabecular number [(2.86 ± 0.06) mm(-1)], mineral apposition rate [(2.32 ± 0.02) µm/d] and index of osteoblast [(30.20 ± 0.47) N/mm(2)] in subchondral region of the cartilage in the experimental group were significantly increased compared with the age-matched controls [respectively (64.00 ± 1.54)%, (87.00 ± 1.13) µm, (1.84 ± 0.08) mm(-1), (1.69 ± 0.02) µm/d and (21.07 ± 0.59) N/mm(2)] (P < 0.05). However, trabecular separation [(170.00 ± 2.25) µm] was lower than those in the controls [(241.50 ± 1.57) µm] with significant difference(P < 0.05). There was no significant difference in the bone histomorphometry parameters of the central region between the experimental group and the age-matched control group (P > 0.05).

CONCLUSIONSThe pattern of bone histomorphometry parameters expression in subchondral region has a high correlation with the adaptive remodeling of the condyle after functional appliance.

Animals ; Cartilage ; anatomy & histology ; growth & development ; Female ; Male ; Mandibular Advancement ; Mandibular Condyle ; anatomy & histology ; growth & development ; Orthodontic Appliances, Functional ; Rabbits ; Random Allocation

OBJECTIVETo propose a new method for automatic segmentation of manually determined knee articular cartilage into 9 subregions for T2 measurement.

METHODSThe middle line and normal line were automatically obtained based on the outline of articular cartilage manually drawn by experienced radiologists. The region of articular cartilage was then equidistantly divided into 3 layers along the direction of the normal line, and each layer was further equidistantly divided into 3 segments along the direction of the middle line. Finally the mean T2 value of each subregion was calculated. Bland-Altman analysis was used to evaluate the agreement between the proposed and manual subregion segmentation methods.

RESULTSThe 95% limits of agreement of manual and automatic methods ranged from -3.04 to 3.20 ms, demonstrating a narrow 95% limits of agreement (less than half of the minimum average). The coefficient of variation between the manual and proposed subregion methods was 4.04%.

CONCLUSIONThe proposed subregion segmentation method shows a good agreement with the manual segmentation method and minimizes potential subjectivity of the manual method.

Adult ; Cartilage, Articular ; anatomy & histology ; Humans ; Knee Joint ; anatomy & histology ; Magnetic Resonance Imaging ; methods ; Young Adult