Medial Plateau Research Articles

An Evaluation of Intra-articular Pathologies Accompanying Tibial Plateau Fractures Postoperatively.

Tibial plateau fractures are one of the most complex and common intra-articular fractures encountered in trauma surgery. This study aimsto evaluate the MRI intra-articular findings of patients with tibial plateau fractures treated surgically and the functional and radiological changes after surgical treatment. A total of 91 patients admitted to our clinic between 2010 and 2019 and operated for tibial plateau fracture were identified from the hospital information system. Patients were excluded fromthe study if aged <18 years, if the radiographs and MRIs were not suitable for the measurements, or if they could not be contacted by telephone. The study was completed with 49 operated knees and 49 healthy knees of 49 patients. The patients were evaluated with respect to demographic characteristics, KneeSocietyKneeScore (KSKS), KneeSocietyFunction Score (KSFS), KneeInjuryandOsteoarthritisOutcomeScore (KOOS) functional and clinical scores, Rasmussen, Kellgren-Lawrence, and Whole-OrganMagneticResonanceImagingScore (WORMS) radiological scoring, and meniscus and ligament pathologies examined on the follow-up MR images. The patients comprised 39 males and 10 females with a mean age of 45.9±11.89 years, and a mean follow-up of 58.2±30.7 months. The fractures were seen to be 49% (n=24)in the lateral plateau, 6.1% (n=4) in the medial plateau, and 42.9% (n=21) were bicondylar fractures involving both plateaux. The KSKS knee score was satisfactory in 85.7% of the patients, the KSFS functional score in 89.7%, and the Rassmussen radiological score in 93.8%. In the KOOS subjective questionnaire, the mean points obtained were 430.7, and the mean total WORMS points were 34.2. According to the Kellgren-Lawrence grades, severe osteoarthritis (grade 3-4) developed in 18.3% (n=9) of the patients. Meniscus injuries that are overlooked at the time of the first injury or which may develop in the subsequent process were not found to seriously affect the functional outcomes of tibial plateau fractures. It can be considered that even if a ligament injury is seen to be accompanying the fracture at the time of the first trauma, the effect is not great in terms of prognosis, and the treatment can remain conservative, especially for collateral ligament injuries.

Relationship of Fracture Morphological Characteristics with Posterolateral Corner Injuries in Hyperextension Varus Tibial Plateau Fractures.

Hyperextension varus tibial plateau fracture (HVTPF) is known to present with concomitant injuries to the posterolateral corner (PLC). However, the exact rate and characteristics of these injuries remain unclear. The primary objective of this study was to explore the rate and characteristics of PLC injuries in HVTPFs. The secondary objective was to investigate the relationship between the fracture morphological features and the associated PLC injuries. Patients with HVTPFs were subdivided into 2 groups: group I (without fracture of the posterior column cortex) and group II (with fracture of the posterior column cortex). Fracture characteristics were summarized qualitatively based on fracture maps and quantitatively based on the counts of morphological parameters. Knee ligamentous and meniscal injuries were assessed using magnetic resonance imaging. The association between fracture characteristics and PLC injuries was analyzed. We included a total of 50 patients with HVTPFs in our study: 28 in group I and 22 in group II. The rate of PLC injuries was 28.6% in group I and 27.3% in group II. In group I, patients with PLC injuries showed fracture lines closer to the anterior rim of the medial plateau and had smaller fracture areas. Furthermore, 6 of the 8 patients with PLC injuries in group I also had posterior cruciate ligament injuries. The rate of PLC injuries is relatively high in HVTPFs. In HVTPFs without fracture of the posterior column cortex, a small fracture area strongly suggests an accompanying PLC injury, and PLC injury is frequently combined with posterior cruciate ligament injury. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Poster 369: Medial and Lateral Posterior Tibial Slope in the Skeletally Immature: A Cadaveric Study

Objectives: Increased knee posterior tibial slope (PTS) angle is risk factor for primary and secondary ACL injury. Adult biomechanical research indicates that decreasing the PTS may reduce ACL injuries, and osteotomy techniques have been developed to alter tibia slope to reduce risk of re-injury. Pediatric and adolescent athletes have the highest rates of primary and secondary ACL injury, and many in this age group may have abnormal PTS angle. The purpose of this study was to evaluate PTS in medial and lateral tibial plateaus in large database of CT scans, and to develop normative PTS data in this age group. Methods: IRB approval was waived, as the specimens were donated for research, no genetic information was collected, and there were no plans for family contact. 83 pediatric knee CT scans, ranging from ages 1 to 12, were analyzed using OsiriX imaging software. The PTS was evaluated at two distinct points on sagittal CT sections: (1) At the medial tibia plateau and 2) lateral tibial plateau, both aligned with the central part of on a coronal view of the medial femoral and lateral femoral condyles respectively condyle. Results: The average medial PTS angle was 6.56° ± 3.84° and 6.81° ± 3.62° for the lateral PTS. There was not a significant statistical difference between the medial and lateral PTS (P = 0.6632, determined using an independent-samples t-test and analysis of variance). When plotting the age versus PTS, we observed a positive correlation with the medial PTS (R2 = 0.0385) and a negative correlation with the lateral PTS (R2 = 0.0393). Conclusions: The data demonstrate variability in medial and lateral pediatric PTS and provides normative values for pediatric PTS values. For pediatric patients undergoing ACL surgeries, consideration of increased PTS values that are associated with higher rates of recurrent ACL injury may influence surgical treatment techniques. Correction of increased PTS to lower ACL injury risk is performed in adults with major corrective osteotomy surgery, but such procedures have not been performed in children due to osteotomy-induced damage to growth plates. Due to open growth plates, pediatric patients may be treated with minimally invasive guide growth procedures to lower PTS, with minimal complication risk. Guided growth procedures have a long history of successful alignment correction in the coronal plane. Future animal and clinic studies may also demonstrate the safety and effectiveness of guided growth sagittal plane correction as applied to increased PTS. PTS developmental anatomy and its relationship to ACL injury is crucial for surgical advancements, including the use of low risk guided growth interventions to reduce PTS and ACL injury in pediatric patients with high risk of recurrent injury.

Exploring consistent ratios in morphometry of the proximal tibia: insights for knee arthroplasty.

The current study, which delves into proximal tibia morphometric parameters in a Greek sample, not only analyzes whether specific linear distance ratios are consistent but also paves the way for a potential novel metric system for knee arthroplasty imaging studies using constant ratios. These findings could have significant implications for future enlarged research and clinical practice. A total of 38 dried tibiae were evaluated by two independent investigators. The following distances were measured with a digital Vernier sliding caliper: (1) the mediolateral distance of the proximal surface (A), (2) the anteroposterior distance of the proximal surface (B), (3) The longitudinal length of the bone (C), (4) the line connecting the anterior margin of the proximal surface with the highest peak of the tibia tuberosity (D), (5) the depth of the proximal margin of the medial articular facet (AF) (medial plateau) (E) and (6) the depth of the proximal margin of the lateral AF (lateral plateau) (F). The A, B, C, D, E, and F mean distances were 71.3mm, 47.4mm, 340.2mm, 37.1mm, 42mm, and 35.9mm. Reliability analysis for each observer on all measurements revealed an interclass correlation (ICC) score of 0.975 (observer 1) and 0.971 (observer 2). The ratio A/B was 1.5, A/C was a constant 0.2, and D/C was 0.1. The ratio E/F was 1.2. The six measurements (A-F) showed excellent inter-observer reliability (all ICC values > 0.990). The study established constant ratios of the studied linear distances around the proximal tibia. Considering these ratios, asymmetrical tibial components in knee arthroplasty seem to replicate the native anatomy more closely. Furthermore, the distance from the anterior margin of the proximal surface to the tibial tuberosity peak, constituting one-tenth of the longitudinal length of the tibia, shows promise as a metric system for imaging studies, especially in assessing lesions around tibial components.

Investigation of the anatomic risk factors in acute anterior cruciate ligament ruptures to develop ramp lesions of the medial meniscus by quantitative MRI

ObjectiveTo investigate the anatomic risk factors of knee in patients with acute non-contact anterior cruciate ligament (aACL) ruptures to develop ramp lesions.MethodsA total of 202 subjects were retrospectively divided into three groups: (1) aACL ruptures combined with ramp lesions group (n = 76); (2) isolated ACL ruptures group (n = 56) and (3) normal controls group (n = 70). Quantitative morphological parameters on MRI were measured including: diameter of medial femoral condyle (MFC), anterior-posterior length and depth of medial tibial plateau (MTP AP length and depth), lateral posterior tibial slope (LPTS) and medial posterior tibial slope (MTPS), asymmetry of LPTS and MPTS (LMPTS), lateral meniscal slope (LMS), and medial meniscal slope (MMS).ResultsThe MTP AP length, MTP AP length/MFC diameter ratio, MTP depth, LPTS and the asymmetry of LMPTS showed significant differences among the three groups (p < 0.001). The risk factors associated with the ramp lesions including a longer MTP AP length (OR 1.17, 95% CI 1.00–1.44, p = 0.044), increased MTP depth (OR 1.91, 95% CI 1.22–3.00, p = 0.005) and lager ratio (OR 1.11, 95% CI 1.01–1.22, p = 0.036). The highest AUC was the MTP AP length/MFC diameter ratio (0.74; 95% CI, 0.66–0.82). The combination model increased higher accuracy (0.80; 95% CI, 0.72–0.88).ConclusionSeveral bony anatomic characteristics of the knee, especially the morphology of medial tibia plateau, are additional risk factors for aACL ruptures to develop ramp lesions.Critical relevance statementPredictive anatomic risk factors of the knee for patients with acute non-contact anterior cruciate ligament (aACL) ruptures to develop ramp lesions, especially the morphology of medial tibia plateau, are detectable by MRI.Key PointsRamp lesion development can complicate aACL ruptures and requires specific treatment.Longer AP length and increased MTP depth are risk factors for concurrent ramp lesions.Identification of ramp lesions allows for the most appropriate treatment.Graphical

Variability Between Full-Length Lateral Radiographs and Standard Short Knee Radiographs When Evaluating Posterior Tibial Slope in Revision ACL Patients.

Increased posterior tibial slope (PTS) has been identified as a risk factor for failure after anterior cruciate ligament (ACL) reconstruction. Correction of PTS may improve outcomes after revision ACL reconstruction. There are conflicting reports demonstrating the measurement of the PTS on standard short knee (SSK) radiographs versus full-length lateral (FLL) radiographs including the entire tibia. To compare PTS measurements between SSK and FLL radiographs in patients who failed primary ACL reconstruction. It was hypothesized that there would be high variability between the SSK and FLL radiographic measurements. Cohort study (diagnosis); Level of evidence, 2. The medial and lateral PTS were measured on the SSK and FLL radiographs of 33 patients with failed primary ACL reconstructions. All measurements were performed by 2 trained independent observers (A.A.M., J.S.), and inter- and intraobserver reliability were calculated using the intraclass correlation coefficient (ICC). Measurements recorded by the observer with the higher intraobserver ICC were used for comparison of the PTS on SSK versus FLL radiographs. Both the inter- and the intraobserver reliability values of the PTS measurements were excellent. There was a significant difference in mean PTS on the medial plateau as measured on the SSK and FLL radiographs (11.2°± 5.3° vs 12.5°± 4.6°; P = .03), with the FLL radiographs demonstrating higher PTS. There was also a significant difference in the mean PTS on the lateral plateau as measured on SSK versus FLL radiographs (10.7°± 4.3° vs 12.2°± 4°, respectively; P = .01), with the FLL radiographs demonstrating higher PTS. Notably, 66.67% of the absolute measurements for PTS on the medial plateau differed by ≥2°, with variability as high as 8.5°. Results indicated that FLL and SSK radiographs are not interchangeable measurements for PTS associated with failed ACL reconstruction. Because FLL radiographs demonstrate less variability than SSK radiographs, we recommend obtaining them to evaluate these complex patients.

Cartilage Collagen Neoepitope C2C Expression in the Articular Cartilage and Its Relation to Joint Tissue Damage in Patients with Knee Osteoarthritis.

Pathological cleavage of type II collagen (Col2) and generation of Col2 neoepitopes can serve as useful molecular markers of the progression of osteoarthritis (OA). One of such potential biomarkers is type II collagen neoepitope C2C. The aim of this study was to correlate the degree of articular cartilage damage in OA patients with C2C expression in histological samples of tissues removed during total knee replacement. Cartilage samples were obtained from 27 patients ranging in age from 55 to 66 years. In each patient, medial and lateral tibia plateau samples were analyzed according to the OARSI histopathology grading system. The C2C expression was evaluated on histological slides by semi-quantitative analysis using ImageJ Fiji 2.14.0 software. Spearman's rank correlation analysis revealed a positive weak correlation (rho = 0.289, p = 0.0356) between the histological grade of tissue damage and the percentage of C2C staining. In addition, a highly significant positive correlation (rho = 0.388, p = 0.0041) was discovered between the osteoarthritis score (combining the histological grade of damage with the OA macroscopic stage) and the percentage of C2C staining in the samples. The C2C expression was detected in all the regions of the articular cartilage (i.e., the superficial zone, mid zone, deep zone and tidemark area, and the zone of calcified cartilage). Our findings imply that local expression of C2C correlates with the articular cartilage damage in OA-affected knees. This confirms that C2C can be used as a prospective marker for assessing pathological changes in the OA course and OA clinical trials.

Analysis of cartilage loading and injury correlation in knee varus deformity.

Knee varus (KV) deformity leads to abnormal forces in the different compartments of the joint cavity and abnormal mechanical loading thus leading to knee osteoarthritis (KOA). This study used computer-aided design to create 3-dimensional simulation models of KOA with varying varus angles to analyze stress distribution within the knee joint cavity using finite element analysis for different varus KOA models and to compare intra-articular loads among these models. Additionally, we developed a cartilage loading model of static KV deformity to correlate with dynamic clinical cases of cartilage injury. Different KV angle models were accurately simulated with computer-aided design, and the KV angles were divided into (0°, 3°, 6°, 9°, 12°, 15°, and 18°) 7 knee models, and then processed with finite element software, and the Von-Mises stress distribution and peak values of the cartilage of the femoral condyles, medial tibial plateau, and lateral plateau were obtained by simulating the human body weight in axial loading while performing the static extension position. Finally, intraoperative endoscopy visualization of cartilage injuries in clinical cases corresponding to KV deformity subgroups was combined to find cartilage loading and injury correlations. With increasing varus angle, there was a significant increase in lower limb mechanical axial inward excursion and peak Von-Mises stress in the medial interstitial compartment. Analysis of patients' clinical data demonstrated a significant correlation between varus deformity angle and cartilage damage in the knee, medial plateau, and patellofemoral intercompartment. Larger varus deformity angles could be associated with higher medial cartilage stress loads and increased cartilage damage in the corresponding peak stress area. When the varus angle exceeds 6°, there is an increased risk of cartilage damage, emphasizing the importance of early surgical correction to prevent further deformity and restore knee function.

A Systematic Review of Bone Bruise Patterns following Acute Anterior Cruciate Ligament Tears: Insights into the Mechanism of Injury.

(1) Background: The purpose of this systematic review was to determine the prevalence of bone bruises in patients with anterior cruciate ligament (ACL) injuries and the location of the bruises relative to the tibia and femur. Understanding the relative positions of these bone bruises could enhance our comprehension of the knee loading patterns that occur during an ACL injury. (2) Methods: The MEDLINE, EMBASE, and the Cochrane Library databases were searched for studies that evaluated the presence of bone bruises following ACL injuries. Study selection, data extraction, and a systematic review were performed. (3) Results: Bone bruises were observed in 3207 cases (82.8%) at the lateral tibia plateau (LTP), 1608 cases (41.5%) at the medial tibia plateau (MTP), 2765 cases (71.4%) at the lateral femoral condyle (LFC), and 1257 cases (32.4%) at the medial femoral condyle (MFC). Of the 30 studies, 11 were able to assess the anterior to posterior direction. The posterior LTP and center LFC were the most common areas of bone bruises. Among the 30 studies, 14 documented bone bruises across all four sites (LTP, MTP, LFC, and MFC). The most common pattern was bone bruises appearing at the LTP and LFC. (4) Conclusions: The most frequently observed pattern of bone bruises was restricted to the lateral aspects of both the tibia and femur. In cases where bone bruises were present on both the lateral and medial sides, those on the lateral side exhibited greater severity. The positioning of bone bruises along the front-back axis indicated a forward shift of the tibia in relation to the femur during ACL injuries.

Research progress on biomechanics for internal fixation in tibial plateau fracture

To review the biomechanical research progress of internal fixation of tibial plateau fracture in recent years and provide a reference for the selection of internal fixation in clinic. The literature related to the biomechanical research of internal fixation of tibial plateau fracture at home and abroad was extensively reviewed, and the biomechanical characteristics of the internal fixation mode and position as well as the biomechanical characteristics of different internal fixators, such as screws, plates, and intramedullary nails were summarized and analyzed. Tibial plateau fracture is one of the common types of knee fractures. The conventional surgical treatment for tibial plateau fracture is open or closed reduction and internal fixation, which requires anatomical reduction and strong fixation. Anatomical reduction can restore the normal shape of the knee joint; strong fixation provides good biomechanical stability, so that the patient can have early functional exercise, restore knee mobility as early as possible, and avoid knee stiffness. Different internal fixators have their own biomechanical strengths and characteristics. The screw fixation has the advantage of being minimally invasive, but the fixation strength is limited, and it is mostly applied to Schatzker typeⅠfracture. For Schatzker Ⅰ-Ⅳ fracture, unilateral plate fixation can be used; for Schatzker Ⅴand Ⅵ fracture, bilateral plates fixation can be used to provide stronger fixation strength and avoid the stress concentration. The intramedullary nails fixation has the advantages of less trauma and less influence on the blood flow of the fracture end, but the fixation strength of the medial and lateral plateau is limited; so it is more suitable for tibial plateau fracture that involves only the metaphysis. Choosing the most appropriate internal fixation according to the patient's condition is still a major difficulty in the surgical treatment of tibial plateau fractures. Each internal fixator has good fixation effect on tibial plateau fracture within the applicable range, and it is an important research direction to improve and innovate the existing internal fixator from various aspects, such as manufacturing process, material, and morphology.

Thermographic Mapping of Arterial Perforators in the Leg.

Preoperative localisation of perforators aids in easy intraoperative dissection. Infrared thermography is a simple, safe, and effective tool with a short learning curve that is useful in identifying perforators. It has been found to have a high concordance rate when compared with computed tomography angiography and is useful in identifying arterial perforators in the leg. To create a thermographic map of arterial perforators in the leg and to determine the correlation between the number of perforators identified and the length of the leg. This was a cross-sectional study. The length of the leg was measured and the location of perforators corresponding to the distribution of the anterior tibial, posterior tibial, and peroneal arteries was identified using thermography. The mean number of perforators corresponding to the different surfaces of the leg was noted, this was then correlated with the length of the leg using the Pearson correlation coefficient. Using thermography, perforators were identified along a line drawn from the medial malleolus to the medial tibia plateau and from the lateral malleolus to the head of the fibula and within 2 cm of these lines. More perforators were found in the middle third of the leg and there was no significant correlation between the number of perforators and the length of the leg. A useful surface marking to aid the identification of perforators in the leg using infrared thermography was found. There was no significant correlation between the length of the leg and the number of perforators.

Measurement of tibial slope using biplanar stereoradiography (EOS®).

Posterior tibial slope (PTS) is an important anatomic parameter of the knee related to anteroposterior instability. Biplanar stereoradiography allows for simultaneous low-dose acquisition of anteroposterior and lateral views with 3D capability, enabling separate lateral and medial plateau analyses. We aimed to evaluate the possibility and compare the reproducibility of measuring medial and lateral PTS on EOS® images with two different patient positionings and compare it with CT of the knees as the gold standard. This is a retrospective study including volunteers who underwent lower limb stereoradiography and knee CT from 01/08/2016 to 07/31/2019. Sixty legs from 30 patients were studied. PTS were measured using stereoradiography and CT by two radiologists. Intraclass correlation was used to calculate intrarater and interrater reproducibilities. Pearson's correlation coefficients were used to calculate the correlation between stereoradiography and CT. We also compared the reproducibility of the stereoradiography of volunteers with 2 different positionings. The mean stereoradiography PTS values for right and left knees were as follows: lateral, 12.2° (SD: 4.1) and 10.1° (SD: 3.5); medial,12.2° (SD: 4.4) and 11.6° (SD: 3.9). CT PTS mean values for right and left knee are as follows: lateral, 10.3° (SD:2.5) and 10.6° (SD: 2.8); medial: 8.7° (SD: 3.7) and 10.4° (SD: 3.5). Agreement between CT and EOS for angles between lateral and medial PTS was good (right, 0.874; left, 0.871). Regarding patient positioning on stereoradiography, interrater and intrarater reproducibilities were greater for patients with nonparallel feet (0.738-0.883 and 0.870-0.975). Stereoradiography allows for appropriate delineation of tibial plateaus, especially in patients with nonparallel feet, for the purpose of measuring PTS. The main advantage is lower radiation doses compared to radiography and CT.

Outcomes of late-stages infantile Blount's disease managed by acute single stage: medial hemi-plateau elevation and metaphyseal osteotomy. Eight case series.

This study aimed to evaluate the clinical and radiological outcomes of surgical intervention involving acute medial hemi-plateau elevation and metaphyseal osteotomy with internal fixation and growth modulation for late-stages Blount's disease. A retrospective analysis was conducted on consecutive patients with late-stages infantile tibia vara between 2014 and 2020. Inclusion criteria consisted of children aged 8 years and older with Blount's disease with Langenskiold stage IV, V or VI, tibia vara more than 30*, medial plateau depression angle (MPDA) exceeding 25* and knee instability with a minimum follow-up period of 3 years. Patients with Limb length discrepancy greater than 5 cm were excluded. Data collection included assessments of age, weight, disease stage, clinical tibiofemoral angle (TFA), mechanical medial proximal tibial angle (mMPTA), MPDA, tibial torsion and knee instability. Functional outcomes were evaluated using modified Pediatric Outcome Data Collection Instruments (PODCI) scores. The study included 5 children with 8 affected limbs. Among them, three children with five limbs had recurrent deformities after previous surgeries. All cases showed significant improvements in TFAs, mMPTA, tibial torsion, knee instability and modified PODCI scores. Complications included 4 cases of superficial infections, 1 intra-articular fracture, 2 minor screw breakage and 2 on-table under correction. Surgical intervention involving acute Single-stage medial hemi-plateau elevation and metaphyseal osteotomy leads to satisfactory outcomes in late-stages Blount's disease among older children. It is crucial to achieve proper correction of all deformity components during surgery, with epiphysiodesis on the lateral side to prevent further recurrence. Continuous follow-up until skeletal maturity is essential for optimal results.

Investigation of Morphometric Factors Associated With Adolescent ACL Rupture.

There are no definitive anatomic morphometric risk factors for adolescent anterior cruciate ligament (ACL) injury. To compare the parameters used to define the tibial and femoral morphometric structure of the knee between adolescent patients with and without ACL rupture. Cross-sectional study; Level of evidence, 3. Included were magnetic resonance imaging (MRI) scans and radiographs of 115 patients aged 10 to 17 years who were evaluated for ACL rupture at a single institution between February 1, 2019, and January 31, 2022. Images from 115 patients with intact MRI scans were included as controls. We investigated the following imaging parameters: tibial slope (on lateral radiograph), lateral condylar height, tibial sulcus height, medial condylar height, condylar width, intercondylar notch with, intercondylar notch angle, notch index, eminence width, tibial plateau width, eminence width/tibial plateau width, medial/lateral/overall eminence height, medial plateau depth, and 2 different eminence angles. Parameters were compared between groups using the chi-square, Fisher exact, Student t, or Mann-Whitney U test, as appropriate. Receiver operating characteristic analysis was conducted for cutoff values of significant parameters. There were no significant differences in age, sex, or side affected between groups. Only the medial plateau depth was found to be statistically significant between the ACL rupture and ACL intact groups (2.6 vs 2.2 mm; P = .015). A statistically significant cutoff value could not be obtained for the medial plateau depth. Medial plateau depth was found to be significantly greater in adolescent patients with ACL rupture compared with ACL-intact controls.

Characterization of the CT-based risk factors for concomitant patellofemoral instability in patients with anterior cruciate ligament injury.

Underestimation of concomitant patellofemoral instability in patients with anterior cruciate ligament (ACL) injury has aroused extensive attention. However, the characteristics of the combined injury is not well recognized. Hence, we aimed to characterize the features of the combined injury, and determine the radiographic risk factors. Fifteen radiological parameters were identified after discussion and pilot-tested. Radiographic measurements were compared using the analysis of variance model with Tukey post hoc analysis. A stepwise binomial logistic regression was performed and a nomogram model combining the significant risk factors was created. The model performance was validated by C-index, calibration plot, and decision curve. A total of 204 patients (mean [SD] age, 25.1 [6.7] years; 108 [52.9%] male) were included. The final model was updated through regression analysis using 4 parameters as significant risk factors: lateral femoral condyle ratio (OR (95% CI), 1.194 (1.023 to 1.409)), medial anterior tibial subluxation (mATS) (OR (95% CI), 1.234 (1.065 to 1.446)), medial posterior plateau tibial angle (mPPTA) (OR (95% CI), 1.266 (1.088 to 1.500)), and trochlear depth (OR (95% CI), 0.569 (0.397 to 0.784)). C-index for the nomogram was 0.802 (95% CI, 0.731 to 0.873) and was confirmed to be 0.784 through bootstrapping validation. Calibration plot established a good agreement between prediction and observation. Decision curve analysis showed that if threshold probability was over 10%, using the nomogram adds more benefit than either all or none scheme. Lateral femoral condyle ratio, mATS, mPPTA, and trochlear depth are strong adverse predictors of patellofemoral instability in patients with ACL injury. This study characterizes the radiological features of the combined injury. Patellofemoral instability should be noted when treating ACL injuries. • The radiological characteristics of the combined ACL injury and patellofemoral instability is not well recognized. • Lateral femoral condyle ratio, mATS, mPPTA, and trochlear depth are predominant risk factors for patellofemoral instability in patients with ACL injury. • Patellofemoral instability should be noted when treating ACL injuries.

Knee joint biomechanics and cartilage damage prediction during landing: A hybrid MD-FE-musculoskeletal modeling.

Understanding the mechanics behind knee joint injuries and providing appropriate treatment is crucial for improving physical function, quality of life, and employability. In this study, we used a hybrid molecular dynamics-finite element-musculoskeletal model to determine the level of loads the knee can withstand when landing from different heights (20, 40, 60 cm), including the height at which cartilage damage occurs. The model was driven by kinematics-kinetics data of asymptomatic subjects at the peak loading instance of drop landing. Our analysis revealed that as landing height increased, the forces on the knee joint also increased, particularly in the vastus muscles and medial gastrocnemius. The patellar tendon experienced more stress than other ligaments, and the medial plateau supported most of the tibial cartilage contact forces and stresses. The load was mostly transmitted through cartilage-cartilage interaction and increased with landing height. The critical height of 126 cm, at which cartilage damage was initiated, was determined by extrapolating the collected data using an iterative approach. Damage initiation and propagation were mainly located in the superficial layers of the tibiofemoral and patellofemoral cartilage. Finally, this study provides valuable insights into the mechanisms of landing-associated cartilage damage and could help limit joint injuries and improve training programs.

Proximal tibial aspect ratio and matching of tibial component in total knee arthroplasty: a narrative review

Proximal tibial aspect ratio (PTAR) is closely related to age, disease status and cutting parameters with considerable inter-individual variation independent of gender and race, nevertheless the aspect ratio of tibial components from different manufacturers remains relatively constant from smallest to largest size. As a result, component mismatching is an unavoidable dilemma during tibia preparation in total knee arthroplasty (TKA). Various prosthesis systems all can achieve more than 80% coverage on proximal tibia, whereas their optimal fit rates are generally not more than 50%. It is difficult for symmetrical components to avoid anteroposterior mismatch, internal malrotation tends to occur when maximum coverage is pursued on the resected surface with a medial dominant plateau or lower PTAR. Although it is easier to achieve a balance of rotation and coverage with anatomical components, significant anteromedial overhang tends to appear on the resected surface with a symmetrical or lateral dominant plateau. Further researches should focus on the law of inter-individual variability of proximal tibial morphology, the quantitative definition of "ideal matching" safety zone of key morphological parameters on different areas of proximal tibia and the methodology of realizing"ideal matching"in the majority patients with the least amount of component sizes. In addition, with the rapid development of additive manufacturing and digital orthopedic technology, individual customized implant is expected to become a breakthrough point in the field of TKA component fitting.

Sufficient Metaphyseal Bone for Wedge Removal and Fixation Hardware During Supratuberosity Tibial Deflexion Osteotomy in Knees With Excessive Posterior Tibial Slope

Background: Tibial deflexion osteotomy (TDO) is sometimes indicated for revision anterior cruciate ligament (ACL) reconstruction in knees with posterior tibial slope (PTS) ≥12° and aims to decrease PTS to around 5°. When planning TDO, measuring the anterior tibial metaphyseal height (aHt) could help ascertain whether the available metaphyseal bone would be sufficient to create the wedge and leave adequate residual bone. Purpose: To (1) determine whether, compared with knees with normal native PTS (<12°), aHt is greater in knees with excessive native PTS (≥12°), and (2) verify if, aiming to decrease PTS to 5°, supratuberosity TDO in knees with excessive native PTS could be performed without tibial tuberosity osteotomy, leaving a minimum of 15 mm of residual bone for fixation staples or plates. Study Design: Cross-sectional study; Level of evidence, 3. Methods: True lateral radiographs of 350 consecutive patients scheduled for ACL reconstruction were digitized to measure PTS, tibial medial plateau length, tibial anterior and posterior metaphyseal heights and inclinations, and patellar height. Measurements were compared between knees with PTS <12° and those with ≥12°. The wedge height required for supratuberosity TDO was estimated for knees with excessive PTS, aiming for a target PTS of 5°, to determine the proportion of knees that would have residual aHt <15 mm. Results: A total of 326 knees had adequate true lateral radiographs. The mean PTS was 9.8°± 3.1° (range, 1°-20°) and exceeded 12° in 83 (25%) knees. There were no significant differences between knees with normal versus excessive PTS when comparing aHt (30.7 ± 4.5 mm vs 31.6 ± 4.9 mm; P = .270) and medial tibial plateau length (43.1 ± 5.4 mm vs 43.3 ± 5.6 mm; P = .910). Setting the target mPTS at 5° for supratuberosity TDO, the mean residual aHt was 25.0 ± 4.4 mm, and 7 (8%) knees had a residual aHt <20 mm, of which only 1 (1%) had residual aHt <15 mm. Setting the target mPTS at 0°, the mean residual aHt was 21.3 ± 4.2 mm, and 36 (43%) knees had a residual aHt <20 mm, of which only 4 (5%) had residual aHt <15 mm. Conclusion: aHt was not significantly different between knees with normal versus excessive PTS. Estimation of the wedge height required for supratuberosity TDO to reduce excessive PTS to 5° revealed sufficient metaphyseal bone for wedge removal in all knees. Furthermore, 99% of knees would have sufficient residual bone (aHt, ≥15 mm) to accommodate fixation staples or plates, without the need for tibial tuberosity osteotomy.

Radiolucent line assessment in cemented stemmed total knee (RISK) arthroplasty: validation of a modernized classification system.

This study aims to implement and assess the inter- and intra-reliability of a modernized radiolucency assessment system; the Radiolucency In cemented Stemmed Knee (RISK) arthroplasty classification. Furthermore, we assessed the distribution of regions affected by radiolucency in patients undergoing stemmed cementedtotal knee arthroplasty. Stemmed totalknee arthroplasty cases over 7-year period at a single institution were retrospectively identified and reviewed. The RISK classification system identifies five zones in the femur and five zones in the tibia in both the anteroposterior (AP) and lateral planes. Post-operative and follow-up radiographs were scored for radiolucency by four blinded reviewers at two distinct time points four weeks apart. Reliability was assessed using the kappa statistic. A heat map was generated to demonstrate the reported regions of radiolucency. 29 cases (63 radiographs) of stemmed totalknee arthroplasty were examined radiographically using the RISKclassification system. Intra-reliability (0.83) and Inter-reliability (0.80) scores were both consistent with a strong level of agreement using the kappa scoring system. Radiolucency was more commonly associated with the tibial component (76.6%) compared to the femoral component (23.3%), and the tibial anterior-posterior (AP) region 1 (medial plateau) was the most affected (14.9%). The RISK classification system is a reliable assessment tool for evaluating radiolucency around stemmed totalknee arthroplasty using defined zones on both AP and lateral radiographs. Zones of radiolucency identified in this study may be relevant to implant survival and corresponded well with zones of fixation, which may help inform future research.

Changes in femoral rollback and rotation with increasing coupling in knee arthroplasty—a biomechanical in-vitro study

BackgroundAfter total knee arthroplasty, 10–30% of patients still complain about knee pain, even after exact positioning of the components. Altered knee kinematics are crucial in this regard.The aim of our study was to experimentally determine the influence of different degrees of component coupling of knee prostheses on joint kinematics during muscle-loaded knee flexion in-vitro.MethodsFemoral rollback and femoral rotation of a standard cruciate retaining (GCR), a posterior stabilized (GPS), a rotational hinge (RSL) and a total hinge (SSL) design of the same series of knee replacement implants (SL-series) of one single manufacturer (Waldemar Link GmbH, Hamburg, Germany) were analyzed and set in relation to the motion of the corresponding native knee in a paired study design. All different coupling degrees were analyzed in the same human knees. To simulate muscle loaded knee flexion, a knee simulator was used. Kinematics were measured with an ultrasonic motion capture system and integrated in a calculated coordinate system via CT-imaging.ResultsThe largest posterior motion on the lateral side was found for the native knee (8.7 ± 7.0 mm), followed by the GPS (3.2 ± 5.1 mm) and GCR (2.8 ± 7.3 mm) implants, while no motion was found for the RSL (0.1 ± 3.0 mm) and the SSL (-0.6 ± 2.7 mm) implants. In contrast, on the medial side, only the native knee showed a posterior motion (2.1 ± 3.2 mm). Regarding femoral external rotation, the only implant where the observed difference did not reach statistical significance when compared to the native knee was the GCR (p = 0.007).ConclusionThe GCR and GPS kinematics closely imitate those of the native joint. Medial femoral rollback is reduced, however, with the joint pivoting around a rotational center located in the medial plateau. Without additional rotational forces, the coupled RSL and SSL prostheses closely resemble each other with no femoral rollback or relevant rotational component. The femoral axis, however, shifts ventrally in both models when compared with their primary counterparts. The positioning of the coupling mechanism in the femoral and tibial component thus can already lead to altered joint kinematics even in prostheses with an identical surface geometry.