Medial Tibiofemoral Joint Research Articles

MRI radiation images to predict cartilage injury secondary to posterior horn tear of the medial meniscus

To investigate the correlation between the duration of medial meniscus posterior horn tear (MMPHT) disease and medial meniscus extrusion (MME) to calculate the rate of progression of MME and to predict cartilage damage in the medial tibiofemoral joint. The differences in MME, MJSW, and MME/MMBW between the two MRI examinations were statistically significant (P < 0.001). Follow-up MRI showed increased cartilage damage grading of medial femoral condyle (MFC) and medial tibial plateau (MTP) from the first examination (P < 0.001). The incidence of grade 2–4 cartilage damage in patients increased by 15.0% and 11.7%, respectively.There was a significant correlation between the ΔMME and MRI examination interval (R2 = 0.868); the rate of MME progression showed an increase of 0.026 ± 0.034 mm per month. The cut-off values for predicting cartilage damage in the MTP and MFC were 0.012 and 0.008, respectively. The ΔMME gradually increases with the prolonged duration of MMPHT. MME progression rate can validly predict cartilage damage in the medial tibiofemoral joint. These findings suggest that monitoring the rate of MME progression in patients with MMPHT could be a useful predictor of cartilage damage, potentially aiding in early intervention and management strategies.

Evaluation of the usefulness of non-weight-bearing tunnel view using X-ray in the short term after medial meniscus posterior root tear onset: a retrospective study

BackgroundThis study aimed to examine whether the non-weight-bearing tunnel view X-ray is effective for short-term evaluation of medial meniscus posterior root tear (MMPRT) by assessing the X-ray characteristics at the initial and follow-up visits.MethodsThis was a retrospective longitudinal study of 26 enrolled knees diagnosed with MMPRT on magnetic resonance imaging. The distance between the medial tibial eminence and medial femoral condyle (MTE–MFC distance) and medial tibiofemoral joint (MTFJ) width were measured by obtaining non-weight-bearing tunnel view and frontal view X-ray radiographs. The initial and follow-up values at a median interval of 17 days were compared. Additionally, the correlations between the MTE–MFC distance increase rate and body mass index (BMI), age, femorotibial angle (FTA), and posterior tibial slope (PTS) were evaluated using linear regression analysis.ResultsThe tunnel view images of the initial and follow-up X-rays showed a significant increase in the MTE–MFC distance and a significant decrease in the MTFJ width. Furthermore, a moderate correlation was observed between the change in the MTE–MFC distance and the time interval between X-rays. However, no substantial correlation was observed for the change in the MTFJ width over time. Moreover, no significant correlation was observed between the change in the MTE–MFC distance in the non-weight-bearing tunnel view and BMI, age, FTA, and PTS.ConclusionsThe non-weight-bearing tunnel view is highly beneficial for evaluating MMPRT progression in the short term.

Hip and pelvic geometry as predictors of knee osteoarthritis severity.

Malalignment is one of the most critical risk factors for knee osteoarthritis (KOA). Biomechanical factors such as knee varus or valgus, hip-knee-ankle angle, and femoral anteversion affect KOA severity. In this study, we aimed to investigate KOA severity predictive factors based on hip and pelvic radiographic geometry. In this cross-sectional study, 125 patients with idiopathic KOA were enrolled. Two investigators evaluated the knee and pelvic radiographs of 125 patients, and 16 radiological parameters were measured separately. KOA severity was categorized based on the medial tibiofemoral joint space widths (JSW). Based on JSW measurements, 16% (n = 40), 8.8% (n = 22), 16.4% (n = 41), and 56.8% (n = 147) were defined as grades 0, 1, 2, 3, respectively. There were significant differences between the JSW groups with respect to hip axis length, femoral neck-axis length, acetabular width, neck shaft angle (NSA), outer pelvic diameter, midpelvis-caput distance, acetabular-acetabular distance, and femoral head to femoral head length (P < .05). Two different functions were obtained using machine learning classification and logistic regression, and the accuracy of predicting was 74.4% by using 1 and 89.6% by using both functions. Our findings revealed that some hip and pelvic geometry measurements could affect the severity of KOA. Furthermore, logistic functions using predictive factors of hip and pelvic geometry can predict the severity of KOA with acceptable accuracy, and it could be used in clinical decisions.

Biomechanical impact of meniscal ramp lesions on knee joint contact characteristics in ACL deficient knees: a cadaveric analysis.

To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus. Twelve cadaveric knees (six matched pairs) were subjected to a 600N axial load using a custom testing jig, which allowed for knee positioning at 0°, 45°, and 90° of flexion without other constraints. The knees were randomly assigned to either a ramp lesion group (n = 6) or a posterior root lesion group (n = 6). Four testing conditions were examined: (1) intact, (2) isolated ramp lesion, (3) isolated posterior root tear of the medial meniscus, and (4) combined ramp lesion and posterior root tear of the medial meniscus. Contact characteristics were evaluated using a flexible pressure sensor, the I-Scan System. Peak contact pressure in isolated ramp lesions (4.15 ± 0.98MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47MPa, P = 0.003) were significantly higher than that in the intact condition. The knee flexion position significantly affected the medial tibiofemoral joint's contact area, contact pressure, and peak contact pressure (P < 0.001 for all). Isolated ramp lesions did not significantly impact force transmission, contact area, or contact pressure. In contrast, isolated root lesions and combined ramp and posterior root tears of the medial meniscus significantly intensified the changes in contact characteristics in the medial tibiofemoral joint compared to the intact condition. Level III.

Characteristics of Acute Cartilage Response After Mechanical Loading in Patients with Early-Mild Knee Osteoarthritis.

This study determined whether the acute cartilage response, assessed by cartilage thickness and echo intensity, differs between patients with early-mild knee osteoarthritis (OA) and healthy controls. We recruited 56 women aged ≥ 50years with Kellgren-Lawrence (KL) grade ≤ 2 (age, 70.6 ± 7.4years; height, 153.7 ± 5.2cm; weight, 51.9 ± 8.2kg). Based on KL grades and knee symptoms, the participants were classified into control (KL ≤ 1, asymptomatic, n = 27) and early-mild knee OA groups (KL 1 and symptomatic, KL 2, n = 29). Medial femoral cartilage thickness and echo intensity were assessed using ultrasonographic B-mode images before and after treadmill walking (15min, 3.3km/h). To investigate the acute cartilage response, repeated-measures analysis of covariance (groups × time) with adjusted age, external knee moment impulse, steps during treadmill walking, and cartilage thickness at pre-walking was performed. A significant interaction was found at the tibiofemoral joint; after walking, the cartilage thickness was significantly decreased in the early-mild knee OA group compared to the control group (p = 0.002). At the patellofemoral joint, a significant main effect of time was observed, but no interaction was detected (p = 0.802). No changes in cartilage echo intensity at either the tibiofemoral or patellofemoral joints, and no interactions were noted (p = 0.295 and p = 0.063). As acute cartilage response after walking, the thickness of the medial tibiofemoral joint in the early-mild knee OA was significantly reduced than that in the control group. Thus, greater acute deformation after walking might be a feature found in patients with early-mild knee OA.

Marrow stimulation procedures for high‐grade cartilage lesions during surgical repair of medial meniscus root tear yielded suboptimal outcomes, whilst small lesions showed surgical eligibility

AbstractPurposeTo investigate the surgical outcomes of arthroscopic pull‐out repair for medial meniscus root tear (MMRT) combined with the marrow stimulation procedures (MSP) for accompanying high‐grade cartilage lesions.MethodsPatients who underwent arthroscopic pull‐out repair for MMRT between 2010 and 2019 were retrospectively reviewed. Patients who had at least 3 years of follow‐up were included and classified into two groups according to whether MSP (microfracture or microdrilling) were performed on cartilage lesions in the medial tibiofemoral joint (group 1, patients with International Cartilage Repair Society [ICRS] grade 0–3a lesions and did not undergo MSP; group 2, patients with ICRS grade 3b–3d lesions and underwent MSP). Comparative analyses, including non‐inferiority trials, were conducted between groups for subjective and objective outcomes. In addition, group 2 was further divided into two subgroups according to cartilage lesion size and compared with group 1 (group S, ≤ 2.0 cm2; group L, &gt; 2.0 cm2).ResultsA total of 94 patients were included (group 1, 68 patients; group 2, 26 patients). There were no significant differences in clinical scores at postoperative 3 years and final follow‐up between groups 1 and 2, but group 2 failed to satisfy the non‐inferiority criteria compared to group 1 overall. In objective outcomes, group 2 did not meet the non‐inferiority criteria for the rate of osteoarthritis progression compared to group 1, and it also showed a significantly higher proportion of high‐grade osteoarthritis at final follow‐up (P = 0.044) and a higher degree of osteoarthritis progression than group 1 (P = 0.03 for pre‐ to postoperative 3 years, and P = 0.006 for pre‐ to final follow‐up). In additional evaluations comparing the subgroups of group 2 and group 1, group S showed relatively favourable results compared to group L in objective outcomes at final follow‐up.ConclusionPatients who underwent arthroscopic pull‐out repair for MMRT combined with MSP for accompanying high‐grade cartilage lesions showed suboptimal outcomes compared to those with no or low‐grade lesions at mid‐term follow‐up. High‐grade cartilage lesions ≤ 2.0 cm2 may be candidates for the surgical repair of MMRT if MSP are performed, but those with larger lesions may require alternative treatment strategies.Level of evidenceIII.

Assessment of a novel deep learning-based software developed for automatic feature extraction and grading of radiographic knee osteoarthritis

BackgroundThe Kellgren-Lawrence (KL) grading system is the most widely used method to classify the severity of osteoarthritis (OA) of the knee. However, due to ambiguity of terminology, the KL system showed inferior inter- and intra-observer reliability. For a more reliable evaluation, we recently developed novel deep learning (DL) software known as MediAI-OA to extract each radiographic feature of knee OA and to grade OA severity based on the KL system.MethodsThis research used data from the Osteoarthritis Initiative for training and validation of MediAI-OA. 44,193 radiographs and 810 radiographs were set as the training data and used as validation data, respectively. This AI model was developed to automatically quantify the degree of joint space narrowing (JSN) of medial and lateral tibiofemoral joint, to automatically detect osteophytes in four regions (medial distal femur, lateral distal femur, medial proximal tibia and lateral proximal tibia) of the knee joint, to classify the KL grade, and present the results of these three OA features together. The model was tested by using 400 test datasets, and the results were compared to the ground truth. The accuracy of the JSN quantification and osteophyte detection was evaluated. The KL grade classification performance was evaluated by precision, recall, F1 score, accuracy, and Cohen's kappa coefficient. In addition, we defined KL grade 2 or higher as clinically significant OA, and accuracy of OA diagnosis were obtained.ResultsThe mean squared error of JSN rate quantification was 0.067 and average osteophyte detection accuracy of the MediAI-OA was 0.84. The accuracy of KL grading was 0.83, and the kappa coefficient between the AI model and ground truth was 0.768, which demonstrated substantial consistency. The OA diagnosis accuracy of this software was 0.92.ConclusionsThe novel DL software known as MediAI-OA demonstrated satisfactory performance comparable to that of experienced orthopedic surgeons and radiologists for analyzing features of knee OA, KL grading and OA diagnosis. Therefore, reliable KL grading can be performed and the burden of the radiologist can be reduced by using MediAI-OA.

Analysis of the correlation between media meniscus displacement index and medial tibiofemoral articular cartilage damage

To investigate the correlation between the medial meniscal indentation index (MDI) and medial tibiofemoral articular cartilage damage more than 3 degrees in patients aged 40 to 60 years old with suspected or complicated knee osteoarthritis at non-weight-bearing position, and to determine the predictive threshold. From June 2016 to June 2020, a total of 308 patients who underwent initial knee arthroscopic exploration for chronic knee pain were collected. The age ranged from 36 to 71 years old with an average of(56.40±1.82) years old, including 105 males and 203 females. And patients with extra-articular malformations (abnormal force lines), a history of trauma, inflammatory arthritis and other specific arthritis were excluded. Finally, 89 eligible cases were obtained, aged from 42 to 60 years old with an average of (59.50±0.71) years old, including 45 males and 44 females. The degree of cartilage damage in the medial compartment of the knee joint was recorded, which was divided into two groups(≥degree 3 and<degree 3) according to Outer-Bridge classification system. The possible risk factors were determined by univariate analysis in the age, gender, affected sides, body mass index (BMI), synovial thickening grade, meniscus injury and MDI of 2 groups. Then, the independent risk factors for cartilage injury of more than grade 3 were determined by further binary Logistic regression analysis. If MDI was taken as an independent risk factor, receiver operating characteristic (ROC) analysis was performed to confirm whether it had diagnostic value for cartilage damage of above degree 3 and calculate the critical value of MDI. A total of 89 eligible patients were obtained. Univariate analysis showed age, BMI, MDI and meniscus injury may be the independent risk factors for cartilage damage of more than 3 degrees, further binary Logistic regression analysis confirmed that MDI[OR=1.66, 95%CI(1.64, 1.69), P=0.01]and BMI [OR=1.58, 95%CI(1.17, 2.15), P=0.03] were independent risk factors for cartilage injury of more than degree 3 in enrolled patients. ROC analysis showed that MDI had more diagnostic value than BMI, and the critical value was 0.355 with a sensitivity of 89.1% and a specificity of 88.2%. In doubt or accompanied by 40 to 60 years old patients with knee osteoarthritis, the MDI measured by non-weight-bearing knee MRI has predictive value for cartilage injury of more than degree 3 in medial tibiofemoral joint, and the critical value for diagnosis of cartilage injury of more than degree 3 is 0.355.

Quantification of Synovial Fluid Using Magnetic Resonance Fingerprinting Multicomponent Imaging in the Articular Cartilage of the Knee

The purpose of this study was to verify the feasibility of magnetic resonance fingerprinting (MRF)-derived synovial fluid fraction (SFF) mapping for quantifying subvoxel-sized cartilage defects. MRF was performed on a 3-Tesla scanner and used to derive T2 and SFF maps. An ex vivo experiment was performed using bovine bone; different numbers of holes (4, 6, 8, 10, and 12) were drilled separately on the articular surface, and SFF values were compared among the drilled areas. In a clinical study, 16 osteoarthritis patients underwent sagittal 3D fast spinecho (FSE) and MRF scanning, and knee cartilage segmentation was performed on each image. For morphologic analysis, fluid-excluded images of the SFF (FEISFF) and T2 maps (FEIT2) were generated using the cartilage segmentations, and the whole-organ magnetic resonance imaging score (WORMS) of each FEI and 3D FSE image were compared using the kappa coefficient. For quantitative analysis, intact cartilage volumes in the SFF (VSFF) and T2 maps (VT2) were calculated, and their correlations with reference to the actual cartilage volume on 3D FSE images (V3D) were evaluated. In the ex vivo experiment, the SFF value increased as the number of holes increased. The kappa coefficients of the WORMS were 0.80 and 0.64 in the SFF and T2 maps, respectively, and substantial to almost perfect agreement was observed in the medial tibiofemoral joint. The V3D-VSFF and V3D-VT2 correlation coefficients differed by 0.03 or more in the medial tibiofemoral joint. The MRF-derived SFF map can feasibly evaluate small, invisible cartilage defects and quantify cartilage volumes.

Comparison of medial tibiofemoral joint mechanics between all-suture anchors and transtibial pullout technique for posterior medial meniscal root tears

BackgroundThe posterior medial meniscal root tear (PMMRT) seriously impacts the tibiofemoral joint biomechanics. Two available techniques for PMMRT repair include the transtibial pullout (TPO) repair and all-suture anchor (ASA) repair techniques. These techniques have not been compared biomechanically.MethodsA total of 20 fresh porcine cadaveric knee specimens were used. All 20 knees were randomly and evenly distributed into four groups (five specimens per group): (1) intact posterior meniscal root, (2) PMMRT, (3) TPO repair technique for PMMRT, and (4) ASA repair technique for PMMRT. The tibiofemoral contact mechanics were investigated using a pressure sensor. All knee specimens were tested by being loaded with 600 N axial compressive force at three different flexion angles (0°, 45°, and 90°). The contact surface area, contact pressure, peak pressure, and time-zero displacement were recorded.ResultsThe PMMRT caused a significant decrease in contact surface area, an increase in contact pressure, and peak pressure from the reference values observed in the intact meniscus group (P = 0.05, 0.016, and 0.008, respectively). After fixation, no significant difference was observed between the ASA and intact group. Meanwhile, significant differences were found between the TPO and intact group in terms of contact surface area, contact pressure, and peak pressure. In the comparison between the two techniques, the ASA group demonstrated higher contact surface area than the TPO group at the average knee flexion angle (p = 0.05).ConclusionFor most testing conditions, the ASA technique demonstrated superior biomechanical property in terms of contact surface area compared with the TPO technique under compressive loading conditions. The ASA technique could also restore the tibiofemoral contact mechanics to be comparable with those of the native intact knee. Meanwhile, a significant difference in tibiofemoral mechanics, compared with the intact knee, could be observed in the TPO technique.

Effect of toe-out gait modification on patellofemoral joint loading.

BackgroundToe-out gait has been proposed as a conservative treatment to reduce medial tibiofemoral joint loading. However, patellofemoral joint loading during toe-out gait is not yet understood. Research questionDoes the toe-out gait modification affect patellofemoral joint loading? MethodsSixteen healthy adults were enrolled in this study. The natural gait and toe-out gait were measured using a three-dimensional motion analysis and a force plate. The knee flexion angle and external knee flexion moment during the stance phase were calculated. Thus, dynamic knee joint stiffness, a proxy of patellofemoral joint loading, was defined as a linear regression of the knee flexion moment and knee flexion angle during the early stance. Additionally, the peak patellofemoral compressive force during the early stance was calculated using a musculoskeletal simulation. A paired t-test was used to compare these biomechanical parameters during the natural gait and toe-out gait. ResultsThe toe-out gait significantly increased the peak patellofemoral compressive force (mean difference = 0.37 BW, P = 0.017) and dynamic knee joint stiffness (mean difference = 0.07%BW*Ht/°, P = 0.001). The 1st peak of the knee flexion moment also significantly increased in the toe-out gait (mean difference = 1.01%BW*Ht, P = 0.003); however, the knee flexion angle did not change significantly (initial contact: mean difference = 1.7°, P = 0.078; peak: mean difference = 1.3°, P = 0.224). SignificanceToe-out gait increased the patellofemoral compressive force and dynamic knee joint stiffness because of increasing knee flexion moment, but not the knee flexion angle. When the toe-out gait is adapted, clinicians should pay attention to an increase in the patellofemoral joint loading.

Calcitriol-Loaded Multifunctional Nanospheres with Superlubricity for Advanced Osteoarthritis Treatment.

Osteoarthritis (OA) is characterized by the lubrication dysfunction of a cartilage sliding interface caused by chronic joint inflammation, and effective nonsurgical therapy for advanced OA remains lacking. Addressing chronic joint inflammation, lubrication dysfunction, and cartilage-tissue degradation simultaneously may hopefully tackle this challenge. Herein, we developed superlubricative zein@alginate/strontium@calcitriol (ZASC) nanospheres to treat advanced OA. ZASC was confirmed to significantly improve joint lubrication through traditional tribological tests and our proposed tribological experiment to mimic the intra-articular condition based on the human medial tibiofemoral joint tissues. This finding was attributed to the hydration lubrication formed around the alginate-strontium spheres that enabled ball-bearing lubrication and the filling of cartilage defects. Moreover, ZASCs that released calcitriol in a sustained manner showed proliferative, anti-inflammatory, and anti-apoptosis effects in vitro. Further experiments demonstrated that ZASC exerted chondroprotective effects by inhibiting the breakdown of the extracellular matrix in patient-derived OA cartilage explants. In vivo results demonstrated that ZASC can effectively maintain a normal gait to improve joint function, inhibit abnormal bone remodeling and cartilage degradation in early OA and can effectively reverse the advanced OA progression. Therefore, ZASC is a potentially nonsurgical therapeutic strategy for advanced OA treatments.

"Accuracy of Medial Tibiofemoral Joint Space Palpation Among Second- Year Doctor of Physical Therapy Students Using Ultrasound Verification: An Observational Study"

"Accuracy of Medial Tibiofemoral Joint Space Palpation Among Second- Year Doctor of Physical Therapy Students Using Ultrasound Verification: An Observational Study"

An electronic force sensor accurately detects increased but not decreased soft tissue tension in total knee arthroplasty

BackgroundPostoperative knee instability is a leading cause of revision total knee arthroplasty (TKA). This study used a commercially available insert-shaped electronic force sensor to measure joint loads and facilitate ligament balance adjustment, and assessed the ability of this sensor to detect increased or decreased soft tissue tension during primary TKA. MethodsChanges in medial and lateral tibiofemoral joint loads during knee flexion were evaluated with sensor thicknesses ranging from 10 to 16 mm using six varus osteoarthritis cadaver knees with intact medial collateral ligaments (MCLs), and the measurements were repeated after MCL resection. Correlations between joint loads and maximum knee extension angle were also evaluated. To validate the efficacy of the sensor, the values were compared with those obtained using a conventional tension device. ResultsFor MCL-intact knees in extension, the medial joint load increased with sensor thickness. The maximum knee extension angle decreased with sensor thickness (ρ = −0.4), resulting in extension restriction up to −20°. Knee flexion contracture was below 5° when the total tibiofemoral joint load was below a cut-off of 42 lb. After the MCL was resected, medial joint loads remained unchanged at low values, even with increased sensor thickness. In contrast, the tension device clearly detected an increased gap as the degree of tension decreased. ConclusionsThe electronic sensor identified increased joint loads associated with increased ligament tension, and could predict knee flexion contracture during TKA. However, unlike the tension device, it did not accurately detect excessively decreased ligament tension.

Tibiofemoral Load Magnitude and Distribution During Load Carriage.

Chronic exposure to high tibiofemoral joint (TFJ) contact forces can be detrimental to knee joint health. Load carriage increases TFJ contact forces, but it is unclear whether medial and lateral tibiofemoral compartments respond similarly to incremental load carriage. The purpose of our study was to compare TFJ contact forces when walking with 15% and 30% added body weight. Young healthy adults (n = 24) walked for 5minutes with no load, 15% load, and 30% load on an instrumented treadmill. Total, medial, and lateral TFJ contact peak forces and impulses were calculated via an inverse dynamics informed musculoskeletal model. Results of 1-way repeated measures analyses of variance (α = .05) demonstrated total, medial, and lateral TFJ first peak contact forces and impulses increased significantly with increasing load. Orthogonal polynomial trends demonstrated that the 30% loading condition led to a curvilinear increase in total and lateral TFJ impulses, whereas medial first peak TFJ contact forces and impulses responded linearly to increasing load. The total and lateral compartment impulse increased disproportionally with load carriage, while the medial did not. The medial and lateral compartments responded differently to increasing load during walking, warranting further investigation because it may relate to risk of osteoarthritis.

Managing Genu Varum in Adolescents to Reduce Risks of Progression to Knee Osteoarthrosis

Introduction: Genu varum is not uncommon in adolescents. Managing the condition to reduce its progression may decrease the prevalence of incident knee osteoarthrosis in adulthood. The present review examines studies on risk factors contributing to the progression of genu varum and associated with the degeneration of the medial tibiofemoral joint. We proposed approaches to decrease the magnitude of genu varum and external knee adduction moment, to reduce the incidence of knee osteoarthrosis in the aged population. Methods and Materials: Literature searches were conducted in Pubmed, Embase, and Cochrane Systematic Reviews, using keywords individually and in combinations. We excluded papers on pathological genu varum, tibia vara, Blount disease, nutritional rickets, imaging, and surgery and included only articles on genu varum involving children and young adults. Reference lists of the included papers were also screened manually for additional references. Results and Discussion: Search results showed that many children with physiologic genu varum are deficient or insufficient in vitamin D. High-impact exercises in late children and adolescents promote genu varum. In contrast, therapeutic exercises reduce the magnitude of genu varum in young adults with postural bowlegs. Lateral wedge insoles decrease the external knee adduction moment. We proposed to check the serum vitamin D level of children and adolescents with genu varum. Growing children with genu varum should be advised to reduce the frequency of performing high-impact exercises. Adolescents with genu varum should strengthen the external hip rotators and use lateral wedged insoles.

Biomechanical assessment of disease outcome in surgical interventions for medial meniscal posterior root tears: a finite element analysis

BackgroundThe adverse consequences of medial meniscus posterior root tears have become increasingly familiar to surgeons, and treatment strategies have become increasingly abundant. In this paper, the finite element gait analysis method was used to explore the differences in the biomechanical characteristics of the knee joint under different conditions.MethodsBased on CT computed tomography and MR images, (I) an intact knee (IK) model with bone, cartilage, meniscus and main ligaments was established. Based on this model, the posterior root of the medial meniscus was resected, and (ii) the partial tear (PT) model, (iii) the entire radial tear (ERT) model, and (iv) the entire oblique tear (EOT) model were established according to the scope and degree of resection. Then, the (v) meniscus repair (MR) model and (vi) partial meniscectomy (PM) model were developed according to the operation method. The differences in stress, displacement and contact area among different models were evaluated under ISO gait loading conditions.ResultsUnder gait loading, there was no significant difference in the maximum stress of the medial and lateral tibiofemoral joints among the six models. Compared with the medial tibiofemoral joint stress of the IK model, the stress of the PM model increased by 8.3%, while that of the MR model decreased by 18.9%; at the same time, the contact stress of the medial tibiofemoral joint of the ERT and EOT models increased by 17.9 and 25.3%, respectively. The displacement of the medial meniscus in the ERT and EOT models was significantly larger than that in the IK model (P < 0.05), and the tibial and femoral contact areas of these two models were lower than those of the IK model (P < 0.05).ConclusionsThe integrity of the posterior root of the medial meniscus plays an important role in maintaining normal tibial-femoral joint contact mechanics. Partial meniscectomy is not beneficial for improving the tibial-thigh contact situation. Meniscal repair has a positive effect on restoring the normal biomechanical properties of the medial meniscus.

Magnetic resonance imaging predictors (cartilage, osteophytes and meniscus) of prevalent and 3-year incident medial and lateral tibiofemoral knee joint tenderness and patellofemoral grind

ObjectiveTo identify magnetic resonance imaging (MRI) predictors (cartilage [C], osteophytes [O] and meniscus [M] scores) of prevalent and 3-year incident medial tibiofemoral (MTF) and lateral tibiofemoral (LTF) knee joint tenderness and patellofemoral (PF) grind. MethodsPopulation-based knee pain cohort aged 40–79 was assessed at baseline (N = 255), 3- and 7-year follow-up (N = 108 × 2 = 216). COM scores were measured at 6/8/6 subregions respectively. Age-sex-BMI adjusted logistic models predicted prevalence versus relevant COM predictors (medial, lateral or patellar / trochlear groove scores). Fully adjusted models also included all relevant COM predictors. Binary generalized estimating equations models predicting 3-year incidence were also adjusted for individual follow-up time between cycles.ResultsSignificant predictors of prevalent MTF tenderness: medial femoral cartilage (fully adjusted odds ratio [aOR] 1.84; 95% confidence interval [CI] 1.11, 3.05), female (aOR = 3.05; 1.67, 5.58), BMI (aOR = 1.53 per 5 units BMI; 1.10, 2.11). Predictors of prevalent LTF tenderness: female (aOR = 2.18; 1.22, 3.90). There were no predictors of prevalent PF grind in the fully adjusted model. However, medial patellar osteophytes was predictive in the age-sex-BMI adjusted model. There were no predictors of 3-year incident MTF tenderness. Predictors of 3-year incident LTF tenderness: female (aOR = 3.83; 1.25, 11.77). Predictors of 3-year incident PF grind: lateral patellar osteophytes (aOR = 4.82; 1.69, 13.77). In the age-sex-BMI adjusted model, patellar cartilage was also a predictor.ConclusionWe explored potential MRI predictors of prevalent and 3-year incident MTF/LTF knee joint tenderness and PF grind. These findings could guide preemptive strategies aimed at reducing these symptoms in the present and future (3-year incidence).

Effect of functional weightbearing versus non-weightbearing quadriceps strengthening exercise on contact force in varus-malaligned medial knee osteoarthritis: A secondary analysis of a randomized controlled trial

BackgroundKnee osteoarthritis progression may be related to altered knee loads, particularly in those with varus malalignment. Using randomized controlled trial data, this secondary analysis of complete datasets (n = 67) compared the effects of a functional weightbearing (WB) and non-weightbearing quadriceps strengthening exercise (NWB) program on measures of medial tibiofemoral joint contact force (MTCF) during walking. MethodsParticipants aged ≥50 years and with medial knee osteoarthritis and varus malalignment were randomly allocated to a 12-week, home-based, physiotherapist-prescribed exercise program comprised of WB exercises (n = 31), or NWB exercise (n = 36). Three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from six lower-limb muscles were acquired during walking at baseline and at 12-weeks follow-up. An electromyogram-informed neuromusculoskeletal model estimated bodyweight (BW) normalized MTCF (peak and impulse), including external and muscular contributions to MTCF. ResultsThere was no between-group difference in the change in peak MTCF (−0.02 [−0.12, 0.09] BW) or MTCF impulse (−0.01 [−0.06, 0.03] BW·s). There was a between-group difference in the muscle contribution to peak MTCF (−0.08 [−0.15, −0.00] BW) and MTCF impulse (−0.04 [−0.08, −0.00] BW·s), whereby the muscle contribution reduced more in the NWB group over time compared to the WB group. There was also a between group-difference in the external contribution to peak MTCF (0.09 [0.01, 0.18] BW), but this reduced more in the WB group than in the NWB group. ConclusionsOur findings suggest no difference in MTCF between the two exercise programs, but differences in the contribution to MTCF between the two exercise programs were observed in those with medial knee osteoarthritis and varus malalignment.

Knee Joint Loading Distribution With Vest-borne Loads

Vest borne loads increase tibiofemoral joint (TFJ) contact forces, but the TFJ contact forces do not always increase proportionally to the increase in load (Lenton et al., 2018). It is unclear if and how increase in TFJ contact forces are attenuated during load carriage.PURPOSE: To determine the effects of load carriage on total, medial (MTFJ), and lateral (LTFJ) tibiofemoral joint contact forces, and to determine if increases in joint loads are attenuated via gait adaptations. METHODS: Twelve young, healthy adults (6 males [BMI = 22.19] and 6 females [BMI = 20.38]; 22 + 1.6 yrs), walked for 5 minutes per condition at 1.4 m·s-1 on an instrumented treadmill while carrying vest borne loads of 0%, 15%, and 30% body weight during 3D motion capture. Hip, knee, and ankle kinematic and kinetic data were used as inputs to an inverse-dynamics informed musculoskeletal model of axial TFJ contact force. Kinematic and TFJ contact force comparisons were made via repeated measures ANOVA. RESULTS: From 0% load to 15% and from 0% to 30%, total peak TFJ increased 14% and 32% (3.44 vs 3.92 vs 4.55 body weights (BW) p < 0.001); peak MTFJ increased 12% and 26.5% (2.42 vs 2.72 vs 3.05 BW, p < 0.001); peak LTFJ increased 13% and 38% (1.29 vs 1.46 vs 1.79 BW, p < 0.001), and leg stiffness decreased 10% and 28% (7.17 vs 6.46 vs 5.10 N/mm, p < 0.001), respectively. CONCLUSION: Young, healthy participants do not attenuate the increase in total and medial knee joint contact forces with increasing magnitude of load carriage. They respond to load by decreasing joint stiffness through small increases in dorsiflexion, knee flexion, and hip flexion, which does increase shock absorption and assists with energy transfer (Kinoshital, 1985). These minor increases in flexion coupled with increases in vertical ground reaction forces led to the approximately proportional relative percent increase in TFJ and MTFJ as compared to the increase in load. However, the increase in LTFJ from 0% load to 30% load was 8% greater indicating a disproportional increase in the lateral compartment, assuming that “disproportional” is greater or less than 5%. Further research should investigate if greater increases in load magnitude continue to lead to proportional increases in total TFJ and MTFJ, and disproportional increases LTFJ, especially in military populations who frequently carry heavy loads.