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

OBJECTIVE: To explore 3.0T MRI accurate measurement of knee cartilage thickness in healthy youth provides reliable anatomical parameters for quantitative diagnosis of osteoarthritis and accurate osteotomy of joint replacement. METHODS: From January 2013 to December 2013, 30 healthy young volunteers including 14 males and 16 females with an average age of (25.8±2.4) years old ranging from 22 to 33 years were recruited in Changchun, Jilin Province, and a 3.0T MRI scan was performed on the bilateral knee joints of each volunteer. The cartilage thickness was measured on the lateral femoral condyle (LFC), medial femoral condyle (MFC), lateral tibial plateau (LTP) and medial tibial plateau (MTP). RESULTS: In four regions of the knee joint:LFC, MFC, LTP and MTP, whether young men or women, there was no significant difference in cartilage thickness between the left and right knee joints (P>0.05). There were significant differences in knee cartilage thickness between healthy young men and women (P<0.05). In the same sex group, LFC cartilage thickness was thinner in the middle, thicker in front and rear;MFC cartilage thickness was the thinnest in front and gradually thickening from the front to the rear; LTP cartilage thickness was thickest in the middle, second in the rear and thinnest in the front;MTP cartilage thickness was the thinnest in the front, was relatively uniform in the middle and rear and thicker than that in the front. CONCLUSION In Northeast China, among healthy adults aged 22 to 33, gender difference may be an important factor in the difference of cartilage thickness in various regions of the knee joint. Regardless of whether male or female healthy young people, the cartilage thickness of the entire knee joint is unevenly distributed, but there is no significant difference in cartilage thickness in the same area between the left and right knee joints.
Adult ; Adolescent ; Humans ; Male ; Female ; Young Adult ; Cartilage, Articular/diagnostic imaging* ; Knee Joint/surgery* ; Osteoarthritis ; Magnetic Resonance Imaging ; Femur

ObjectiveCurrently, magnetic resonance imaging (MRI) is the most commonly used imaging modality for observing the growth and development of mesenchymal stem cells (MSCs) after in vivo transplantation to treat osteoarthritis (OA). However, it is a challenge to accurately monitor the treatment effects of MSCs in the zone of calcified cartilage (ZCC) with OA. This is especially true in the physiological and biochemical views that are not accurately detected by MRI contrast agents. In contrast, ultrashort time echo (UTE) MRI has been shown to be sensitive to the presence of the ZCC, creating the potential for more effectively observing the repair of the ZCC in OA by MSCs. A special focus is given to the outlook of the use of UTE MRI to detect repair of the ZCC with OA through MSCs. The limitations of the current techniques for clinical applications and future directions are also discussed.

Data SourcesUsing the combined keywords: "osteoarthritis", "mesenchymal stem cells", "calcified cartilage", and "magnetic resonance imaging", the PubMed/MEDLINE literature search was conducted up to June 1, 2017.

Study SelectionA total of 132 published articles were initially identified citations. Of the 132 articles, 48 articles were selected after further detailed review. This study referred to all the important English literature in full.

ResultsIn contrast, UTE MRI has been shown to be sensitive to the presence of the ZCC, creating the potential for more effectively observing the repair of the ZCC in OA by MSCs.

ConclusionsThe current studies showed that the ZCC could be described in terms of its histomorphology and biochemistry by UTE MRI. We prospected that UTE MRI has been shown the potential for more effectively observing the repair of the ZCC in OA by MSCs in vivo.

Cartilage, Articular ; diagnostic imaging ; Humans ; Magnetic Resonance Imaging ; methods ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells ; physiology ; Osteoarthritis ; diagnostic imaging ; therapy

OBJECTIVE: To retrospectively evaluate the relationship between T2 values of pre- and post-contrast magnetic resonance (MR) images of femoral cartilage in patients with varying degrees of osteoarthritis. MATERIALS AND METHODS: A total of 19 patients underwent delayed gadolinium-enhanced MRI of cartilage. Six regions of interest for T2 value measurement were obtained from pre- and post-contrast T2-weighted, sagittal, multi-slice, multi-echo, source images in each subject. Regions with modified Noyes classification grade 2B and 3 were excluded. Comparison of T2 values between pre- and post-contrast images and T2 values among regions with the grade 0, 1 and 2A groups were statistically analyzed. RESULTS: Of a total of 114 regions, 79 regions showing grade 0 (n = 46), 1 (n = 18), or 2A (n = 15) were analyzed. The overall and individual T2 values of post-contrast images were significantly lower than those of pre-contrast images (overall, 35.3 +/- 9.2 [mean +/- SD] vs. 29.9 +/- 8.2, p < 0.01; range of individual, 28.9-37.6 vs. 27.1-36.4, p < 0.01). Pearson correlation coefficients showed a strong positive correlation between pre- and post-contrast images (rho-Pearson = 0.712-0.905). T2 values of pre- and post-contrast images of the grade 0 group were significantly lower than those of the grade 1/2A group (pre T2, p = 0.003; post T2, p = 0.006). CONCLUSION: T2 values of the femoral cartilage of the knee joint are significantly lower on post-contrast images than on pre-contrast images. Furthermore, these T2 values have a strong positive correlation between pre- and post-contrast images.
Adult ; Aged ; *Cartilage, Articular/pathology ; Contrast Media/*diagnostic use ; Female ; Femur ; Gadolinium DTPA/diagnostic use ; Humans ; Knee Joint ; Magnetic Resonance Imaging/*methods ; Male ; Middle Aged ; Osteoarthritis, Knee/*diagnosis/pathology ; Retrospective Studies

OBJECTIVETo observe therapeutic efficacy of osteoarthritis treated by electroacupuncture, and explore its function of promoting cartilage restoration.

METHODSAccording to random digital table, sixty cases of knee osteoarthritis (60 knees) were randomly divided into an electroacupuncture group and a physiotherapy group, 15 cases (30 knees) in each one. The electroacupuncture was applied at Neixiyan (EX-LE 4), Dubi (ST 35), Heding (EX-LE 2) and Xuehai (SP 10) in the electroacupuncture group, once every other day. The physiotherapy group was treated by medium-frequency therapeutic apparatus every day. For both groups, 4 weeks of treatment were required. The Lysholm knee scoring scale (LKSS) was used to evaluate and compare the knee joints function before and after treatment. At the same time, the GE Signa EXCITE Twin Speed HD 1.5T was used to take MRI examination of knee joints, and measure the T2 values in 10 sub-regions of the cartilage of tibiofemoral joints.

RESULTSCompared before treatment, the LKSS score of both groups were improved with significant differences except item demands for support (P < 0.01, P < 0.05). Between the two groups after treatment, there were significant differences on total score, item instability and swelling (all P < 0.05), the electroacupuncture group was better than the physiotherapy group, but no significant difference on the other items (all P > 0.05). In the electroacupuncture group after treatment, T2 value in anterior lateral tibial sub-region (LTa) was significantly lowered (P < 0.05), but no significant difference in the other nine sub-regions (all P > 0.05). In the physiotherapy group, T2 value in any sub-region was not significantly different before and after treatment (all P > 0.05).

CONCLUSIONElectroacupuncture could effectively improve the symptom, sign and knee joint's function of patients with knee osteoarthritis. Compared with physiotherapy, it has more superior effect and considered as a better non-operative treatment for osteoarthritis. Electroacupuncture also has positive influence on T2 value in cartilage, indicating that electroacupuncture may have the function of promoting cartilage restoration.

Adult ; Aged ; Cartilage, Articular ; diagnostic imaging ; Electroacupuncture ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Osteoarthritis, Knee ; diagnostic imaging ; therapy ; Radiography ; Treatment Outcome

Iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) is a recently developed method for robust separation of fat and water with very high signal-to-noise-ratio (SNR) efficiency. In contrast to conventional fat-saturation methods, IDEAL is insensitive to magnetic field (B0 and B1) inhomogeneity. The aim of this study was to illustrate the practical application of the IDEAL technique in reducing metallic artifacts in postoperative patients with metallic hardware. The IDEAL technique can help musculoskeletal radiologists make an accurate diagnosis particularly in musculoskeletal imaging by reducing metallic artifacts, enabling the use of contrast enhancement, improving SNR performance, and providing various modes of MR images with one scan parameter.
Adipose Tissue ; Adult ; Aged ; *Artifacts ; Body Water ; Cartilage, Articular/pathology ; Contrast Media/diagnostic use ; Humans ; Least-Squares Analysis ; Magnetic Resonance Imaging/*methods ; Male ; Metals ; Middle Aged ; Phantoms, Imaging ; *Prostheses and Implants ; Signal-To-Noise Ratio

Calcium Pyrophosphate ; metabolism ; Cartilage, Articular ; metabolism ; pathology ; Chondrocalcinosis ; diagnostic imaging ; metabolism ; pathology ; surgery ; Diagnosis, Differential ; Female ; Gout ; pathology ; Humans ; Knee Joint ; diagnostic imaging ; metabolism ; pathology ; Male ; Menisci, Tibial ; metabolism ; pathology ; Middle Aged ; Osteoarthritis ; etiology ; pathology ; Radiography

The objective of this research work is to prepare a new and reliable radiopharmaceutical for osteoarthral cartilage imaging. Chondroitin sulfate (CS) was labeled directly with 99mTc by "pretinning" method, the labeling efficiency was 79.30% +/- 1.72% and radiochemical purity was 90.12% +/- 1l.23% after filtration by use of asepsis filter membrane. The biodistribution of 99Tc-CS was studied at 10, 30 min and 1, 2, 3, 4, 5, 6, 7, 8, 9 h respectively after caudal vein injection in normal mice,which showed that the radiolabeled product was washed out from blood quickly, and it was mainly excreted through kidney, but 99mTc-CS had distinctive characteristic of philo- cartilage. Scintigraphy of 99mTc-CS was performed on the rabbit with ostarthritis at 5 h after intravenous injection; the scintigram was clear,and the focus showed increased radiopharmaceutical uptake. The radioactivity ratio of the injured/uninjured side (T/NT) calculated over the region of interest (ROI) was 3.0 +/- 0.6 (P < 0.05). These results indicate that 99mTc-CS is an easily prepared compound with the characteristic of high philo-cartilage and it may be a new ideal cartilage imaging agent.
Animals ; Cartilage, Articular ; diagnostic imaging ; Chondroitin Sulfates ; Female ; Male ; Mice ; Mice, Inbred BALB C ; Organotechnetium Compounds ; chemical synthesis ; Osteoarthritis ; diagnostic imaging ; Rabbits ; Radionuclide Imaging ; Radiopharmaceuticals ; chemical synthesis ; Random Allocation

Osteoarthritis (OA) is a chronic joint disease that involves degeneration of articular cartilage, limited intra-articular inflammation manifested by synovitis and changes in the subchondral bone. After the articular cartilage's stability and complex structure in the framework of pressure-proof were destruct, the ability to repair by itself was weak. Therefore early diagnosis in the treatment of osteoarthritis is a focal ponit. This paper addressed on the characteristics of diagnosis of OA in the relevant objective diagnostic methods.
Adult ; Aged ; Bone Density ; physiology ; Bone and Bones ; diagnostic imaging ; pathology ; Calcification, Physiologic ; Cartilage, Articular ; diagnostic imaging ; pathology ; Female ; Humans ; Joints ; diagnostic imaging ; pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Osteoarthritis ; diagnosis ; epidemiology ; Osteoarthritis, Knee ; diagnosis ; diagnostic imaging ; Radiography ; Radionuclide Imaging ; Synovial Membrane ; diagnostic imaging ; pathology ; Ultrasonography