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

PURPOSE: End-stage knee osteoarthritis (OA) patients are the primary candidates for total knee arthroplasty (TKA). However, most morphological refinements of TKA prosthesis are based on anatomical data from the knees of healthy individuals. This study aimed to determine whether differences exist in key bony morphological characteristics of the distal femur and proximal tibia between osteoarthritic knees and healthy knees. METHODS: This was a retrospective cross-sectional observational study with a case-control design. Patients who were aged ≥ 50 years, had no history of trauma, fracture, or surgery in the studied knee, and had no obvious knee flexion contracture were included in this study by CT scans. Patients who met the American College of Rheumatology clinical criteria for knee OA were included in the study group. Kellgren-Lawrence grade III or IV knees were studied (for bilateral cases, the more severely affected knee was chosen). Patients who presented with unilateral knee pain or trauma were included in the control group, with CT scans from the opposite (asymptomatic) knee used for analyzing. The studied knee had a Kellgren-Lawrence grade of 0 or I and showed no abnormalities upon physical examination. Archived knee CT scans from 160 patients were divided into 2 groups: the study group (80 moderate-to-severe OA knees) and the control group (80 healthy knees). After 3-dimensional reconstruction and virtual cutting using a CT workstation, 13 morphological parameters of the distal femur and proximal tibia were compared between the 2 groups using independent-samples t-tests. RESULTS: No significant group differences in the femoral anteroposterior dimension (p = 0.797), height of the lateral femoral condyle (p = 0.268), posterior condylar angle (p = 0.240), tibial anteroposterior dimension (p = 0.536), or tibial lateral anteroposterior dimension (p = 0.702) were observed. However, the femoral mediolateral dimension (p = 0.002), distal femoral aspect ratio (femoral mediolateral dimension/femoral anteroposterior dimension) (p < 0.001), height of the femoral trochlear groove (p < 0.001), height of the medial femoral condyle (p < 0.001), tibial mediolateral dimension (p = 0.001), proximal tibial aspect ratio (tibial mediolateral dimension/tibial anteroposterior dimension) (p = 0.004), tibial medial anteroposterior dimension (p = 0.005), and tibial asymmetry ratio (tibial medial anteroposterior dimension/tibial lateral anteroposterior dimension) (p = 0.006) were all significantly greater in the study group. CONCLUSION Knees with moderate-to-severe OA are significantly wider than healthy knees, and OA is a risk factor for increased tibial platform asymmetry. When refining the morphological parameters of TKA prostheses, the specific bony morphological characteristics of OA knees should be taken into account to reduce the potential risk of femoral or tibial component underhang and facilitate optimal balance between tibial component fit and rotational alignment.
Humans ; Osteoarthritis, Knee/pathology* ; Male ; Female ; Cross-Sectional Studies ; Retrospective Studies ; Arthroplasty, Replacement, Knee ; Middle Aged ; Aged ; Case-Control Studies ; Prosthesis Design ; Knee Prosthesis ; Femur/anatomy & histology* ; Tibia/anatomy & histology* ; Tomography, X-Ray Computed ; Knee Joint/diagnostic imaging*

OBJECTIVE: To explore correlation between imaging classification of knee osteoarthritis (KOA) and axis angle of tibiofemoral and patellofemoral joints. METHODS: A retrospective analysis of 739 middle-aged and elderly patients with KOA (1 026 knee joints) who underwent vertical X-ray examination of both lower limbs and lateral knee joints from September 2018 to December 2020. Among them, 63 patients with K-L 0 grade (95 knee joints), 100 patients with K-L 1 grade (130 knee joints), 161 patients with K-L 2 grade (226 knee joints), 187 patients with K-L 3 grade (256 knee joints), and 228 patients of K-L 4 grade (319 knee joints). According to relative position of knee joint center and line between hip joint center and ankle joint center, the affected knee was divided into varus group(844 knees joints) and valgus group (182 knees joints). According to Install-Salvati method, the affected knee was divided into three groups, such as high patella (patella height>1.2 mm, 347 knees joints), median patella (patella height ranged from 0.8 to 1.2 mm, 561 knees joints), and low patella (patella height<0.8 mm, 118 knees joints). Lower femur angle, upper tibia angle, femoral neck shaft angle, femoral tibial angle, joint gap angle, hip-knee-ankle angle, patella-femoral angle and patella height among different groups were observed and compared. RESULTS: (1) In varus KOA group, there were statistical differnces in hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, joint space angle, and femoral neck shaft angle of patients with different K-L grades (P<0.05). Hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, joint space angle and K-L grade were significantly positively correlated at 0.01(P<0.05);femoral neck shaft angle and K-L grade showed negative correlation at 0.01(P<0.05). (2) In valgus KOA group, hip-knee-ankle angle, there were statistical differences in tibiofemoral angle, inferior femoral angle, superior tibial angle, joint space angle, and femoral neck shaft angle of patients with different K-L grades(P<0.05). Hip-knee-ankle angle, tibiofemoral angle, lower femoral angle, upper tibial angle, and femoral neck shaft angle showed negative correlation with K-L grades at level of 0.01 (P<0.05);joint gap angle and K-L grades showed significantly positive correlation at level of 0.01(P<0.05). (3) In high patella group, there were statistically differences in patellar height and patellar femoral angle of different K-L grades(P<0.05);there were no statistical difference in patella height and patellar femoral angle of different K-L grades in median patella group. There was no significant difference in patella heightin low patella group with different K-L grades(P>0.05), and there was statistical difference in patellofemoral angle(P<0.05). Patellar height and patella-femoral angle of high patella group were significantly positively correlated with K-L grades at the level of 0.01 (P<0.05);patella height and patella-femoral angle were not correlated with K-L grades in median patella group(P>0.05). There was no correlation between height of patella and K-L grade in low patella group (P>0.05). There was significant negative correlation between patella-femoral angle and K-L grade at level of 0.05 (P<0.05). CONCLUSION Inferior femoral angle, tibiofemoral angle, joint gap angle, hip-knee-ankle angle, femoral neck shaft angle and high patella are related to K-L classification of varus KOA, which could be used for early diagnosis and provide objective data for efficacy analysis of conservative treatment.
Aged ; Middle Aged ; Humans ; Patellofemoral Joint/diagnostic imaging* ; Osteoarthritis, Knee/diagnostic imaging* ; Retrospective Studies ; Knee Joint ; Femur/diagnostic imaging* ; Tibia

OBJECTIVE: To explore relationship between bone marrow edema(BME) and osteoporosis in patients with severe knee osteoarthritis. METHODS: Unmatched case-control study was conducted. Totally 160 patients with severe knee osteoarthritis who had undergone knee magnetic resonance imaging (MRI) and bone mineral density examination (BMD) from January 2020 to March 2021 were included. Eighty patients complicated with BME were included in BME group, and 80 patients without BME were selected as NBME group. In BME group, there were 12 males and 68 females, aged from 51 to 80 years old with an average of(66.58±8.10) years old;the courses of disease ranged from 5 to 40 months with an average of (15.61±9.25) months;body mass index(BMI) ranged from 21.81 to 34.70 with an average of (27.79±3.00) kg·m^-2;25 patients classified to grade Ⅲ and 55 patients grade Ⅳ according to Kellgren- Lawrence(K-L). In NBME group, there were 15 males and 65 females, aged from 50 to 80 years old with an average of(67.82±8.05) years old;the course of disease ranged from 6 to 37 months with an average of(15.75±8.18) months;BMI ranged from 21.39 to 34.46 with an average of (28.26±3.13) kg·m^-2;25 patients were K-L Ⅲ and 55 patients with K-L Ⅳ. The degree of bone marrow edema was evaluated by knee whole oragan magnetic resonance imaging score(WORMS). Osteoporosis was diagnosed and BMD was evaluated by DXA T value. To explore the relationship between bone marrow edema and osteoporosis by comparing prevalence rate of osteoporosis between two groups, and to further explore relationship between BME and BMD by Spearman correlation analysis of BME WORMS score and DXA T value in BME group. RESULTS: The complete case data were obtained on the first diagnosis, and there was no significant difference in sex, age, courses of disease and BMI between two groups (P>0.05). The proportion of K-L Ⅳ in BME group was significantly higher than that in NBME (P<0.05). The prevalence rate of osteoporosis in BME group was significantly higher than in NBME group with the same K-L grade (P<0.001), and there was a strong negative correlation between BME WORMS score and DXA BMD T value (r=-0.812, |r|=0.812 >0.8, P<0.001). CONCLUSION Osteoporosis is one of the risk factors of bone marrow edema in patients with severe knee osteoarthritis, and the lower the bone mineral density is, the easier it is to be complicated with bone marrow edema.
Male ; Female ; Humans ; Osteoarthritis, Knee/diagnostic imaging* ; Bone Marrow/pathology* ; Case-Control Studies ; Bone Marrow Diseases/etiology* ; Osteoporosis/complications* ; Edema/etiology* ; Magnetic Resonance Imaging/methods*

OBJECTIVE: To investigate the relationship between bone marrow edema and pathological changes, symptoms and signs of severe knee osteoarthritis. METHODS: From January 2020 to March 2021, 160 patients with severe knee osteoarthritis who underwrent MRI of the knee at the Department of Bone and Joint, Wangjing Hospital, China Academy of Chinese Medical Sciences were included. Eighty patients with bone marrow edema were selected as the case group, including 12 males and 68 females, aged from 51 to 80 years old with an average of (66.58±8.10) years old, the duration of disease 5 to 40 months with an average of (15.61±9.25) months. Eighty patients without bone marrow edema were selected as the control group, including 15 males and 65 females, aged from 50 to 80 years old with an average of (67.82±8.05) years old, the duration of disease 6 to 37 months with an average of (15.75±8.18) months, BMI was (28.26±3.13) kg·m^-2 ranged from 21.39 to 34.46 kg·m^-2. The degree of bone marrow edema was evaluated by knee whole oragan magnetic resonance imaging score (WORMS). The degree of knee osteoarthritis was evaluated by Kellgren- Lawrence(K-L) grade and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The degree of joint pain was evaluated by visual analogue scale(VAS) and WOMAC pain score, the joint signs were evaluated by tenderness, percussion pain, joint swelling and joint range of motion. To explore the relationship between bone marrow edema and knee osteoarthritis, the prevalence of bone marrow edema and K-L grade were compared between the two groups. Furthermore the WORMS score and WOMAC index, pain-related score, and sign-related score correlation coefficient were analyzed to further explore the relationship between bone marrow edema and knee osteoarthritis index, joint pain symptoms and signs. RESULTS: There was 68.75% (55/80) of the patients in the case group were in K-L grade Ⅳ, and 52.5% (42/80) in the control group, indicating a higher proportion of patients with grade Ⅳ in the case group than the control group (χ²=4.425, P<0.05). In the case group, there was a strong correlation between bone marrow edema WORMS score and knee osteoarthritis WOMAC index. (r=0.873>0.8, P<0.001), a moderate correlation between WORMS score and VAS score and WOMAC pain score(r=0.752, 0.650>0.5, P<0.001), a moderate correlation between WORMS score and percussion pain score (r=0.784>0.5, P<0.001), and a weak correlation between WORMS score and VAS and tenderness score, joint swelling score and joint range of motion score (r=0.194, 0.259, 0.296<0.3, P<0.001). CONCLUSION Our study suggests that severe knee osteoarthritis is associated with an increased risk of bone marrow edema. Bone marrow edema can also lead to knee osteoarthritis joint pain, with percussion pain being a positive sign, but tenderness, joint swelling and limitation of activity are not significantly related to bone marrow edema.
Male ; Female ; Humans ; Osteoarthritis, Knee/pathology* ; Bone Marrow/pathology* ; Knee Joint/diagnostic imaging* ; Bone Marrow Diseases/etiology* ; Pain/pathology* ; Arthralgia ; Edema/pathology*

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

Arthroplasty, Replacement, Knee ; Humans ; Knee Joint/surgery* ; Leg ; Lower Extremity/diagnostic imaging* ; Osteoarthritis, Knee/surgery* ; Rotation ; Tibia/surgery*

OBJECTIVE: Based on the anatomical differences between discoid lateral meniscus(DLM) and normal lateral meniscus (NLM), this study aims to setting up the ultrasound examination parameters to distinguish DLM and NLM and explore the diagnostic value of these parameters on DLM. METHODS: According to the inclusion, exclusion and matching criteria, 66 DLM patients(DLM group) and 132 NLM patients with other knee joint diseases(NLM group), hospitalized from October 2019 to June 2020, were included in this study. There were 18 males and 48 females in the DLM group, ranging in age from 3 to 60 years old, with a mean of (36.9±12.1) years old;36 males and 96 females in the NLM group, ranging in age from 3 to 60 years old, with a mean of (40.0±12.2) years old. Philips high frequency(3.0 to 12.0 MHz) linear array ultrasound probe was used to examine the lateral meniscus of all patients in two groups. Nine parameters including the thickness, width and the included angle of the anterior angle, body and posterior angle respectively in the lateral meniscus were measured. The included angke is formed by the chords of the upper and lower curved surfaces of the meniscus at the free edge. The independent t test was used to analyze the difference of the measured parameters between the DLM group and the NLM group. The receiver operating characteristic(ROC) curve was used to evaluate the cut-off value of each parameter for diagnosing DLM and the corresponding sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve(AUC). RESULTS: The above 9 ultrasound measurement parameters between the DLM group and the NLM group had significant statistical differences(P<0.001). The ROC curve analysis method evaluated the cut-off value and diagnostic capabilities of these nine ultrasound parameters for DLM. The results showed that the cut-off value of the included angle of anterior part, body and posterior part were 25.85°, 24.85° and 29.15 °, respectively;and the sensitivity, specificity, negative predictive value, positive predictive value and AUC were significantly higher than other parameters, which were 88%, 91%, 79%, 95%, 0.94;89%, 94%, 82%, 97%, 0.96; 92%, 97%, 86%, 98%, 0.97, respectively. CONCLUSION Ultrasound diagnosis of DLM is feasible and reliable. The diagnostic ability of the included angle of the anterior part, body and posterior part in the lateral meniscus measured by ultrasound to diagnose DLM are significantly better than other ultrasound measurement parameters, and the sensitivity and specificity of those parameters are close to MRI. Therefore, ultrasound can be used as a reliable method for preliminary diagnosis of DLM.
Adolescent ; Adult ; Child ; Child, Preschool ; Female ; Humans ; Knee Joint/diagnostic imaging* ; Magnetic Resonance Imaging/methods* ; Male ; Menisci, Tibial/diagnostic imaging* ; Middle Aged ; Osteoarthritis, Knee ; Ultrasonography ; Young Adult

Chronic pain of knee osteoarthritis (KOA) greatly affects the quality of life and functional activities of patients. It is important to clarify the underlying mechanisms of KOA pain and the analgesic effect of different therapies. Neuroimaging technology has been widely used in the basic and clinical research of pain. In the recent years, neuroimaging technology has played an important role in the basic and clinical research of KOA pain. Increasing evidence demonstrates that chronic pain in KOA includes both nociceptive and neuropathic pain. The neuropathic mechanism involved in KOA pain is complex, which may be caused by peripheral or central sensitization. In this paper, we review the regional changes of brain pathophysiology caused by KOA pain based on magnetic resonance imaging (MRI), electroencephalogram (EEG), magnetoencephalogram (MEG), near-infrared spectroscopy (NIRS) and other neuroimaging techniques. We also discuss the central analgesic mechanism of different KOA therapies, with a focus on the latest achievements in the evaluation and prediction of pain. We hope to provide new thoughts for the treatment of KOA pain, especially in the early and middle stages of KOA.
Chronic Pain/diagnostic imaging* ; Humans ; Neuroimaging ; Osteoarthritis, Knee/diagnostic imaging* ; Quality of Life ; Technology

OBJECTIVE: To observe the imaging features of focus of knee joint tendon in patients with knee osteoarthritis (KOA) by musculoskeletal ultrasound (MSUS) technique. METHODS: One hundred KOA patients and 100 healthy subjects were included. All the KOA patients were palpated by the sequence of foot RESULTS: The top-5 focus of knee tendon of KOA patients were located in medial inferior patella, medial tibial condyle, inferior patella, Zusanlici and Hedingci. The thickness of ligaments and tendons in extension and flexion positions in KOA patients were thicker than that in healthy subjects ( CONCLUSION The focus of knee joint tendon in KOA patients shows significantly thickened musculoskeletal imaging features.
Healthy Volunteers ; Humans ; Knee Joint/diagnostic imaging* ; Osteoarthritis, Knee/diagnostic imaging* ; Tendons/diagnostic imaging* ; Ultrasonography