Hypertrophic synovial plica in the lateral side of the knee - A case report: Case report and literature review.

INTRODUCTION: Plicae or synovial folds can be detected in different joints, especially around the knee. Synovial plicae pathologies are rare conditions with difficulty in diagnosis because of various symptoms overlapping with other diseases. PRESENTATION OF CASE: We reported a rare case of symptomatic hypertrophic synovial plica in the lateral side of the knee in a 12-year-old boy following a traumatic event almost two years before the surgery. The diagnosis and treatment were conducted by knee arthroscopy, and follow-up of the patients showed significant improvements with no pain or range of motion restrictions. DISCUSSION: The reported case had a significantly lower age of presentations compared to most previously reported cases, and he was diagnosed with lateral knee hypertrophic plicae, while medial knee hypertrophic plicae are more commonly reported, which is considered rare findings. Contrary to previous studies of lateral plica, our case had a history of significant direct trauma, and he was not a professional athlete. Furthermore, based on evidence, hypertrophic synovial plicae are mostly asymptomatic, but in our case, there was a pain in his knee that worsened in flexion. CONCLUSION: Physicians should consider the possibility of synovial hypertrophic plicae, especially in younger patients with histories of direct traumatic events.

Single Leg Hop Performance After Anterior Cruciate Ligament Reconstruction: Ready for Landing but Cleared for Take-Off?

CONTEXT: While the landing phases of the single-leg hop for distance (SLHD) are commonly assessed, limited work reflects how the take-off phase influences hop performance in patients with anterior cruciate ligament reconstruction (ACLR). OBJECTIVE: To compare trunk and lower extremity biomechanics between individuals with ACLR and matched uninjured controls during take-off of the SLHD. DESIGN: Cross-sectional study design. SETTING: Laboratory setting. PATIENTS OR OTHER PARTICIPANTS: 16 individuals with ACLR and 18 uninjured controls. MAIN OUTCOME MEASURES: Normalized quadriceps isokinetic torque, hop distance, and respective limb symmetry indices (LSI) were collected for each participant. Sagittal and frontal kinematics and kinetics of the trunk, hip, knee, and ankle, as well as vertical and horizontal ground reaction forces (GRF) were recorded for loading and propulsion of the take-off phase of the SLHD. RESULTS: Those with ACLR had weaker quadriceps peak torque in the involved limb (p=0.001) and greater strength asymmetry (p<0.001) compared to controls. Normalized hop distance was not statistically different between limbs or between groups (p>0.05) and hop distance symmetry was not different between groups (p>0.05). During loading, the involved limb demonstrated lesser knee flexion angles (p=0.030) and knee power (p=0.007) compared to the uninvolved limb, and lesser knee extension moments compared to the uninvolved limb (p=0.001) and controls (p=0.005). During propulsion, the involved limb demonstrated lesser knee extension moment (p=0.027), knee power (p=0.010), knee (p=0.032) and ankle work (p=0.032), anterior- posterior GRF (p=0.047), and greater knee (p=0.016) abduction excursions compared to the uninvolved limb. CONCLUSIONS: Between-limb differences in SLHD take-off suggest a knee underloading strategy in the involved limb. These results provide further evidence that distance covered during SLHD assessment can overestimate function and fail to identify compensatory biomechanical strategies.

Correlating quadriceps patellar tendon angle and lateral patellar tilt angle in patients with irregular alignment: a cross-sectional study with retrospective data.

Background: The newly defined angle, quadriceps-patella angle (QPA), reflects the combined force transmitted to the patella by the quadriceps muscles and patellar tendon. An increase in QPA may correlate with an increased force on the patella, which is significant in diagnosing patellofemoral instability and pain syndrome. In our study, we examined how various angles and pathologies vary depending on lateral patellar tilt angle (LPTA). QPA and patellar malalignment was investigated. Thus, the importance of understanding patellar malalignment and the research gap. Methods: Three hundred and fifty patients who underwent knee magnetic resonance imaging (MRI) examinations were included. The cross-sectional study conducted retrospectively between the years of 2018-2020 in a tertiary care outpatient clinic. Shapiro-Wilk normality, Chi-square, Mann-Whitney-U, Spearman correlation and receiver operating characteristic (ROC) curve analysis, statistical tests used for analysis. The patellar tendon length, patellar height, tibial tubercle-trochlear groove distance (TT-TG), patella angle, trochlear sulcus angle, trochlear groove depth (TGD), medial trochlea length (MT), lateral trochlea length (LT), medial trochlear/lateral trochlear length ratio (MT/LT), LPTA, patella-patellar tendon angle (PPTA), QPA, Insall-Salvati index (ISI), medial trochlear inclination (MTI), lateral trochlear inclination (LTI) were among these measurements. In addition, we aim to reveal whether there is a significant relationship between two important angles LPTA and QPA. Whether there is a significant increase in the development of chondromalacia for the patient group with LPTA >5°. We examined how the frequency of chondromalacia changes in the patient group with LPTA >5°. Results: Two hundred and seventy seven patients included in the study and many measurements were performed on MRI. Fad-pad edema was found to be significantly higher in the group with LPTA <5° (P=0.046). TT-TG distance was significantly higher, TGD and MT were significantly lower in patients with higher LPTA (P=0.001, P=0.002 and P=0.017, respectively). A low level of significant positive correlation was found between QPA and patellar tendon length. There is no significant difference between QPA and PPTA angles between the groups with LPTA <5° and >5° (P=0.503, P=0.188). In the ROC analysis performed to determine the cut-off value, the LPTA value ≤14.2° which significantly predicted the presence of fad-pad edema, had the highest sensitivity and specificity [sensitivity: 76.71%, specificity: 39.90%, area under the curve (AUC): 0.588, P=0.024]. Conclusions: QPA is independent from many angles of the knee and does not change significantly. As the patellar tendon length increases, QPA angle also increases. In patients with abnormal LPTA, the frequency of TT-TG distance and chondromalacia increased, while TGD and MT decreased. Patients with a low LPTA can be more carefully examined for chondromalacia and fad-pad edema in clinical and MRI examination.

The Current State of Meniscus Replacements.

PURPOSE OF REVIEW: The field of meniscus replacement is changing continuously, with new devices emerging and others disappearing from the market. With the current tendency to preserve the knee joint, meniscus implants may become more relevant than ever. The purpose of this review is to provide an overview of the current state of partial and total meniscus replacements that have been developed beyond the academic phase. The available clinical and pre-clinical data is evaluated, and omissions are identified. RECENT FINDINGS: Recent systematic reviews have shown a lack of homogenous clinical data on the CMI and Actifit meniscal scaffolds, especially regarding long-term performance without concomitant surgical interventions. Clinical studies on the medial total meniscus prostheses NUsurface and Artimis are ongoing, with the NUsurface being several years ahead. New techniques for meniscus replacement are rapidly developing, including the Artimis lateral meniscus prosthesis and the MeniscoFix 3D-printed scaffold. All evaluated clinical studies point towards improved clinical outcomes after implantation of partial and total meniscus replacements. Long-term data on survival and performance is of low quality for CMI and Actifit and is unavailable yet for NUsurface and Artimis. It is of major importance that future research focuses on optimizing fixation methods and identifying the optimal treatment strategy for each patient group. New techniques for total and partial replacement of the medial and lateral meniscus will be followed with interest.

Determination of the effect of preoperative knee joint function on postoperative quality of life in patients with total knee arthroplasty.

Primary total knee arthroplasty (TKA) is one of the most successful procedures for end-stage knee osteoarthritis. To determine the effect of preoperative knee joint function on postoperative quality of life in patients undergoing primary TKA. This descriptive cross-sectional study was conducted with a total of 208 patients in the orthopedics and traumatology clinic. Data were gathered with a personal information form, the Oxford Knee Score (OKS), and the EQ-5D-5L Quality Of Life Scale in the preoperative period, at postoperative 6th week, and at postoperative 3rd month. The data were analyzed using descriptive statistics, one-way analysis of variance (ANOVA), correlation analysis, and simple linear regression analysis. The mean age of the patients was 65.65 ± 7.01 years. Most patients (86.1%) were women, and 51.4% underwent left TKA. OKS scores indicated poor knee function preoperatively and gradually increased at postoperative 6th week and 3rd month. Preoperative OKS was a significant predictor of postoperative knee joint function and quality of life. This study shows that preoperative knee joint function significantly affects postoperative knee joint function and quality of life. These results demonstrate the importance of the surgery timing and suggest that performing surgery earlier in functional decline may be associated with a better outcome.

Efficacy of Mulligan joint mobilizations and trunk stabilization exercises versus isometric knee strengthening in the management of knee osteoarthritis: a randomized controlled trial.

BACKGROUND: Knee osteoarthritis (KOA) progression is often influenced by biomechanical factors. Biomechanical interventions, such as Trunk stabilization exercise (TSE) and Mulligan joint mobilization (MWM), may offer relief from KOA symptoms and potentially slow disease progression. However, the comparative efficacy of these therapies remains uncertain. This study aimed to compare the efficacy of TSE, Mulligan joint mobilization, and isometric knee strengthening (KSE) on disability, pain severity, and aerobic exercise capacity in patients with KOA. METHODOLOGY: A randomized controlled trial (RCT) with three intervention groups was conducted between September 2020 to February 2021. The study enrolled adults aged between 40 and 60 years with a confirmed KOA diagnosis recruited from the physical therapy clinic of the Sindh Institute of Physical Medicine and Rehabilitation, Pakistan. Participants were randomly assigned to receive 24 sessions of either TSE, MWM, or KSE. The knee's functionality was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS), pain on a visual analogue scale (VAS), and two objective functional tests-the 6-minute walk test (6MWT) and the 11-stair climb test (SCT). These assessments were conducted at baseline, the third week, and the sixth week. Changes in outcome measures were analyzed using a mixed-design ANOVA with Bonferroni post-hoc analysis, with statistical significance set at a p-value < 0.05. RESULT: Of the 60 participants, 22 (36.7%) were females, and 38 (63.3%) were males. Within-group analysis revealed a significant improvement in all outcome measures at the third week (p < 0.05) and sixth week (p < 0.05). Notably, the TSE group exhibited a greater reduction in mean difference (M.D) in VAS scores than the MWM and KSE groups across various measures in the third week. At rest, during stair ascent, and descent, the TSE group showed significant improvements in VAS scores: MWM (-2.05; -1.94; -1.94), TSE (-2.38; -2.5; -2.5), KSE (-1.05; -0.63; -0.63). Additionally, during sub-maximal exercise capacity assessment, the TSE group showed greater improvement (MWM 12.89; TSE 22.68; KSE 7.89), as well as in Knee Injury and Osteoarthritis Outcome Score for activities of daily living (KOOS-ADL) (MWM 20.84; TSE 28.84; KSE 12.68), and KOOS-pain (MWM 24.84; TSE 27.77; KSE 5.77) at the third-week assessment (p < 0.05). The TSE group demonstrated significant improvements (p < 0.05) across various measures in the sixth week. Specifically, improvements were observed in VAS scores at rest (MWM - 4.15; TSE - 4.42; KSE - 3.78), during stair ascent (MWM - 3.89; TSE - 4.88; KSE - 3.56) and descent (MWM - 3.78; TSE - 4.05; KSE - 2.94). Furthermore, significant improvements were noted in the stair climb test (MWM - 7.05; TSE - 7.16; KSE - 4.21), 6-minute walk test (6MWT) (MWM 22.42; TSE 37.6; KSE 13.84), KOOS-pain (MWM 41.47; TSE 49.11; KSE 28.73), and KOOS-ADL (MWM 40.31; TSE 50.57; KSE 26.05). CONCLUSION: In this study in patients with KOA, TSE had greater efficacy compared to MWM and KSE in enhancing functional levels, reducing pain, improving sub-maximal exercise capacity, and performance on the stair climb test. Importantly, mean scores between the groups, particularly in the TSE group, reached the minimally important level, particularly in key areas such as pain, functional levels, sub-maximal exercise capacity, and stair climb performance. Clinicians should consider the significant pain reduction, improved functionality, and enhanced exercise capacity demonstrated by TSE, indicating its potential as a valuable therapeutic choice for individuals with KOA. TRIAL NO: ClinicalTrials.gov = NCT04099017 23/9/2019.

Hemophilic pseudotumor of the knee joint: Emphasizing prevention and early diagnosis in a rare disease.

Key Clinical Message: Hemophilic pseudotumors are rare complications occurring in individuals with severe hemophilia, characterized by progressive cystic swellings in muscles and/or bones due to recurrent bleeding. Timely initiation of factor VIII replacement is crucial. Abstract: Hemophilic pseudotumors are rare complications occurring in individuals with severe hemophilia, characterized by progressive cystic swellings in muscles and/or bones due to recurrent bleeding. Although their incidence has decreased with the advent of factor VIII replacement therapy, they still create challenges, particularly in regions with limited access to medical care. Here, we present a case report of a hemophilic pseudotumor of the knee joint in a 15-year-old male with hemophilia A. The patient presented with severe left knee pain, swelling, and restricted range of motion, prompting further investigation. Imaging studies revealed lytic lesions, and MRI bone signal changes consistent with hemophilic pseudotumors. Prompt initiation of factor VIII replacement therapy and supportive management led to a significant improvement in symptoms and joint functionality. Follow-up after 2 months showed that the swelling had significantly reduced in size, with marked improvement in the functionality of the knee joint. This case confirms what is already known in the hemophilia literature: how important it is to prevent, diagnose, and treat pseudotumors early in hemophilia. However, longer clinical and imaging follow-up of this case is necessary to determine whether the complaints associated with pseudotumors resolve with hematologic treatment or will require surgical treatment.

[Pressure digit sign in patients with knee osteoarthritis]. / Signo de digito-presión en pacientes con osteoartritis de rodilla.

INTRODUCTION: it is estimated that 302 million people worldwide are affected by osteoarthritis, corresponding to 60% osteoarthritis (OA) of the knee, which responsible 80% of disability in older adults, hence the importance of the association of the sign with the early inflammatory process in OA. OBJECTIVE: to determine the association of digital pressure sign in patients with and without osteoarthritis of the knee. MATERIAL AND METHODS: this was an observational, comparative cross-sectional study, carried out in patients with and without a diagnosis of knee OA, to whom the digital pressure sign was determined. The sample was calculated with the formula for two proportions, obtaining a total of 40 participants per group, obtained by non-probabilistic sampling for convenience. The statistical analysis included frequencies, percentages, 2 and OR. The bioethics regulations in force were respected. RESULTS: the study included 80 participants, with a median age of 48.9 years (RQI 46-53.7), 73.1% were predominantly female sex (38), and a statistically significant association was found between patients with OA and the presence of digital pressure sign, 2 4.62 and p value = 0.41, OR of 2.65. CONCLUSIONS: the presence of digital pressure sign increases the probability of having OA 2.65 times more.

INTRODUCCIÓN: se estima que 302 millones de personas en el mundo son afectadas por osteoartritis, correspondiendo 60% a osteoartritis (OA) de rodilla, causante de 80% de discapacidad en adultos mayores, de ahí la importancia de la asociación del signo de digito-presión con el proceso inflamatorio temprano en OA. OBJETIVO: determinar la asociación del signo de digito-presión en pacientes con y sin osteoartritis de rodilla. MATERIAL Y MÉTODOS: estudio observacional, transversal comparativo, realizado en pacientes con y sin diagnóstico de OA de rodilla, a quienes se les determinó el signo de digito-presión; la muestra se calculó con la fórmula para dos proporciones que determinó un total de 40 participantes por grupo, obtenidos por muestreo no probabilístico por conveniencia; el análisis estadístico incluyó frecuencias, porcentajes, 2 y OR. Se respetó la reglamentación de bioética vigente. RESULTADOS: el estudio incluyó a 80 participantes, con una mediana de edad de 48.9 años (RIQ 46-53.7), predominó el sexo femenino en 73.1% (38). Se encontró asociación estadísticamente significativa entre pacientes con OA y la presencia del signo de digito-presión, 2 4.62 y p = 0.41, OR de 2.65. CONCLUSIONES: la presencia del signo de digito-presión aumenta 2.65 veces más la probabilidad de tener OA.

Optimal Tai Chi forms in knee osteoarthritis: An exploration from biomechanical rationale to pain reduction.

Objectives: Tai Chi (TC) shows some beneficial effects in reducing pain in knee osteoarthritis (OA). However, the selection of criteria TC forms in previous studies were unclear and inconsistent, possibly accounting for the varying outcomes and rendering the training effects suboptimal. We have selected four optimal TC (OTC) forms based on the knee joint load and its association with pain. This pilot study sought to examine the effect of the OTC forms on reducing knee pain in individuals with knee OA. Methods: Fifteen knee OA participants were recruited. Their knee joint pain level was rated by using the Visual Analogue Scale before and after two weeks of OTC training and compared between these two assessments. Results: The two-week OTC training course was well accepted by our participants. The knee OA pain showed a significant reduction (median pain score: 5 â€‹cm before training and 1 â€‹cm post-training, Wilcoxon p â€‹< â€‹0.001) after the two-week training program. Conclusions: Our pilot results revealed that the 2-week four-form-based OTC program could significantly reduce the knee pain level in people with knee OA. Additionally, our OTC program appears to be about 50% more effective in reducing knee pain than the existing TC-based program, which uses 10 â€‹TC forms over 12 weeks (1.59 vs. 1.06 in Hedge's g). The findings in this study may inform the development of OTC-based knee pain reduction programs and the design of relevant clinical trials to establish OTC's effectiveness, safety, and dose-response relationship in easing knee OA pain.

What Is New about the Semimembranosus Distal Tendon? Ultrasound, Anatomical, and Histological Study with Clinical and Therapeutic Application.

The semimembranosus muscle inserts into several tendons that are associated with some pathologies. Although ultrasound is useful for studying, diagnosing, and managing these pathologies, the correct interpretation of any images requires a clear knowledge of the related anatomical structures and the inter-related functions. We studied 38 cryopreserved non-paired knees from adult anatomical specimens and 4 non-paired knees from 29 to 38-week-old fetuses. The semimembranosus muscle and its tendons were located, observed, and injected under ultrasound guidance. The macroscopic anatomy was studied using dissection and anatomical cuts and the tendons were analyzed histologically. Measurements of muscle were taken 10 cm from the medial epicondyle and just before the tendon divided. The ultrasound facilitated the identification of the different divisions of the tendon of semimembranosus muscle and the rotation of the muscle and tendon from medial to posterior. An anatomical study confirmed this rotation and revealed an average width, thickness, and diameter of 38.29 mm, 14.36 mm, and 112.64 mm, respectively. Important relationships were observed between the divisions of the main tendons and the medial collateral ligament, the posterior side of the knee and popliteus muscle. This information can help to explain knee pathologies and facilitate rehabilitation after surgery.

Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study.

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Bone Age Determination of Epiphyseal Fusion at Knee Joint and Its Correlation with Chronological Age.

Background and Objectives: Bone age determination is a valuable method for forensic and disaster identifications of unknown human remains, as well as for medical and surgical procedural purposes. This retrospective research study aimed to determine the age based on epiphyseal fusion stages and investigate differences related to gender. Materials and Methods: X-rays of the knee were collected from medical imaging centers in hospitals in the south of Jordan and examined by two observers who determined the bone epiphyseal phase of closure for the femur, tibia, and fibula bone ends close to the knee based on a three-stage classification. Results: The main results revealed that females showed earlier epiphyseal union (Stage II) at the lower end of the femur and the upper ends of the tibia and fibula compared to males. In males, the start of complete union (Stage III) at knee bones was seen at the age of 17-18 years, while in females, it was seen at the age of 16-17 years. Additionally, knee bones showed complete union in 100% of males and females in the age groups 21-22 years and 20-21 years, respectively. Although females showed an earlier start and end of epiphyseal complete union than males, analysis of collected data showed no significant age differences between males and females at the three stages of epiphyseal union of the knee bones. Conclusions: Findings of the radiographic analysis of bone epiphyseal fusion at the knee joint are a helpful method for chronological age determination. This study supports the gender and ethnicity variation among different geographical locations. Studies with a high sample number would be needed to validate our findings.

Two for One-Combined Morphologic and Quantitative Knee Joint MRI Using a Versatile Turbo Spin-Echo Platform.

Quantitative MRI techniques such as T2 and T1ρ mapping are beneficial in evaluating knee joint pathologies; however, long acquisition times limit their clinical adoption. MIXTURE (Multi-Interleaved X-prepared Turbo Spin-Echo with IntUitive RElaxometry) provides a versatile turbo spin-echo (TSE) platform for simultaneous morphologic and quantitative joint imaging. Two MIXTURE sequences were designed along clinical requirements: "MIX1", combining proton density (PD)-weighted fat-saturated (FS) images and T2 mapping (acquisition time: 4:59 min), and "MIX2", combining T1-weighted images and T1ρ mapping (6:38 min). MIXTURE sequences and their reference 2D and 3D TSE counterparts were acquired from ten human cadaveric knee joints at 3.0 T. Contrast, contrast-to-noise ratios, and coefficients of variation were comparatively evaluated using parametric tests. Clinical radiologists (n = 3) assessed diagnostic quality as a function of sequence and anatomic structure using five-point Likert scales and ordinal regression, with a significance level of α = 0.01. MIX1 and MIX2 had at least equal diagnostic quality compared to reference sequences of the same image weighting. Contrast, contrast-to-noise ratios, and coefficients of variation were largely similar for the PD-weighted FS and T1-weighted images. In clinically feasible scan times, MIXTURE sequences yield morphologic, TSE-based images of diagnostic quality and quantitative parameter maps with additional insights on soft tissue composition and ultrastructure.

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

PURPOSE: To evaluate the changes in contact characteristics of the tibiofemoral joint resulting from a meniscal ramp lesion in the medial meniscus. METHODS: Twelve cadaveric knees (six matched pairs) were subjected to a 600 N 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. RESULTS: Peak contact pressure in isolated ramp lesions (4.15 ± 0.98 MPa, P = 0.206) showed non-significant increases compared to the intact condition (3.86 ± 1.32 MPa). Peak contact pressure in isolated posterior root tears (4.58 ± 1.70 MPa, P = 0.040) and, combined ramp and posterior root lesions (4.67 ± 1.47 MPa, 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). CONCLUSION: 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 OF EVIDENCE: Level III.

Variations in knee cartilage thickness: Fully automatic three-dimensional analysis of MRIs from five manufacturers.

BACKGROUND: Measurements of knee cartilage thickness derived from MR images are attractive biomarkers for osteoarthritis research. Although some cross-sectional multivendor studies exist, none have employed fully automatic three-dimensional MRI analysis. Our objective was to evaluate the variations in knee cartilage thickness measurements obtained using automated methods and MRI instruments from five different vendors. METHODS: The subjects were 10 healthy volunteers aged 22-60 years. MRI models with 3 Tesla strength from five different companies were used. Cartilage thickness was quantified fully automatically for seven regions. We hypothesized that "the MRI model influences cartilage thickness measurements." Inter-measurement error, defined as the absolute difference between the targeted and median thicknesses determined by the five MRI models, was analyzed using histograms. The factors generating the largest inter-measurement error were also examined. RESULTS: No exceptional trends attributable to a specific instrument model were observed, and the p-value from the Kruskal-Wallis test exceeded 0.05 in all seven regions. Therefore, the study hypothesis was rejected. Of the 350 measurements, the inter-measurement error was ≤0.05 mm in 53 %, ≤0.10 mm in 75 %, and ≤0.20 mm in 95 %. Analysis of the medial tibial cartilage, which had the largest inter-measurement error, revealed mis-extraction of synovial fluid as cartilage. CONCLUSIONS: The choice of MRI model did not influence cartilage thickness measurements. Overall, 95 % of the inter-measurement errors were within 0.20 mm. The greatest error resulted from mis-extracting synovial fluid as cartilage.

The diagnostic value of TT-TG and TT-ME distances in the assessment of patellofemoral instability.

PURPOSE: This study aims to evaluate the application value of the tibial tubercle-trochlear groove distance (TT-TG distance) and tibial tubercle-midepicondyle distance (TT-ME distance) on CT images in patellofemoral instability, and further investigate the association between knee joint rotation angles and patellofemoral instability. METHODS: We retrospectively analyzed CT image data of 59 patients with patellar dislocation (case group) and 39 normal knee joints (control group). We measured the TT-TG distance, TT-ME distance, and knee joint rotation angle (KJRA) of both groups, and the related indicators were analyzed using single-factor/multi-factor binary logistic stepwise regression analysis. Two senior radiologists were assigned to assess the inter-rater reliability. Interclass correlation coefficients (ICC) were calculated. Finally, we used receiver operating characteristic (ROC) curves to compare the diagnostic efficiency of these indicators in patellofemoral instability. RESULTS: The results found significant differences between both groups in terms of TT-TG distance, TT-ME distance, KJRA angle, age, location, and gender (P < 0.05). In terms of inter-rater reliability, TT-TG distance and TT-ME distance ratios showed an excellent correlation between observers (TT-TG inter-rater ICC 0.969, TT-ME inter-rater ICC 0.955). Univariate logistic regression analysis indicated that except for location and gender, all other factors significantly affected patellofemoral instability (P < 0.05). The multivariate logistic regression analysis revealed that the TT-ME distance, age, and KJRA angle were statistically significant factors related to patellofemoral instability, with TT-ME distance being a risk factor for patellofemoral instability (OR value 1.572, P value 0.000). Moreover, the ROC curve analysis demonstrated that the diagnostic capability of the TT-ME distance for detecting patellofemoral instability was higher than that of the TT-TG distance and KJRA (AUC were 0.912, 0.851, and 0.735, respectively). CONCLUSION: The TT-ME distance, age, and knee joint rotation angle are factors that affect patellofemoral instability. The TT-ME distance has better diagnostic efficiency for patellofemoral instability compared to the TT-TG distance and knee joint rotation angle.

Impact of treadmill running on distal femoral cartilage thickness: a cross-sectional study of professional athletes and healthy controls.

PURPOSE: This present study aimed to assess the impact of treadmill running on distal femoral cartilage thickness. METHODS: Professional athletes aged 20 to 40 years with a history of treadmill running (minimum 75 min per week for the past three months or more) and age-, sex-, and body mass index (BMI)-matched healthy controls were recruited. Demographics and clinical features of participants were recorded. Athletes were divided into subgroup 1 with less than 12 months of treadmill running and subgroup 2 with 12 months or more of treadmill running. Distal femoral cartilage thicknesses were measured at the midpoints of the right medial condyle (RMC), right intercondylar area (RIA), right lateral condyle (RLC), left medial condyle (LMC), left intercondylar area (LIA), and left lateral condyle (LLC) via ultrasonography. RESULT: A total of 72 athletes (mean age: 29.6 ± 6.6 years) and 72 controls (mean age: 31.9 ± 6.7 years) were enrolled. Athletes had significantly thinner cartilages in the RLC (2.21 ± 0.38 vs. 2.39 ± 0.31 cm, p = 0.002), LLC (2.28 ± 0.37 vs. 2.46 ± 0.35 cm, p = 0.004), and LMC (2.28 ± 0.42 vs. 2.42 ± 0.36 cm, p = 0.039) compared with the control group. Furthermore, cartilage thickness was significantly thinner in subgroup 2 athletes compared with the control group in the RLC (2.13 ± 0.34 vs. 2.39 ± 0.31 cm, p = 0.001), LLC (2.22 ± 0.31 vs. 2.46 ± 0.35 cm, p = 0.005), and LMC (2.21 ± 0.46 vs. 2.42 ± 0.36 cm, p = 0.027); however, subgroup 1 athletes did not have such differences. There was a weak negative correlation between total months of treadmill running and cartilage thickness in the RLC (r = - 0.0236, p = 0.046) and LLC (r = - 0.0233, p = 0.049). No significant correlation was found between the distal femoral cartilage thickness at different sites and the patients' demographic features, including age, BMI, speed and incline of treadmill running, and minutes of running per session and week (p > 0.05). CONCLUSION: Compared with healthy controls, professional athletes with a history of long-term high-intensity treadmill running had thinner femoral cartilages. The duration (months) of treadmill running was weakly negatively correlated with distal femoral cartilage thickness. Longitudinal studies with prolonged follow-ups are needed to clarify how treadmill running affects femoral cartilage thickness in athletes.

Femorotibial rotation is Linearly Associated with Tibial Tubercle-Trochlear Groove Distance: A Cadaveric Study.

OBJECTIVES: A tibial tubercle-trochlear groove (TT-TG) distance of 20 millimeters (mm) is typically used when determining whether tibial tubercle medialization is performed for surgical treatment of patellar instability. Without knowledge of the variability of an individual's TT-TG distance influenced by through-the-knee femorotibial rotation, the use of a specific TT-TG distance during pre-operative planning for patellar instability may lead to incorrect decisions on the use of tibial tubercle medializtion. We hypothesized that knee joint IE rotation is related to the TT-TG distance. METHODS: Eight independent human cadaveric knee specimens (age: 32 ± 6 years; 4 males, 4 females) were utilized. A robotic manipulator (ZX165U, Kawasaki Robotics, Wixom, MI, USA) instrumented with a universal force/moment sensor was used to determine knee joint IE rotation under applied moments of ±5 newton-meters (Nm) at full extension. Two independent reviewers selected the trochlear groove and tibial tuberosity points on computerized tomography (CT) images of each specimen to define TT-TG. To determine the influence of knee joint IE rotation on TT-TG distance, three-dimensional (3D) models generated from CT scans were registered to tibiofemoral kinematics. Linear regression was performed to determine the relationship between knee joint IE rotation and TT-TG distance. The regression coefficient and standard error of measurement (α = 0.05), and coefficient of determination (r2) were reported. RESULTS: At 0° of rotation, the mean TT-TG distance was 14.2 ± 5.0 mm. Knee joint IE rotation averaged 23.0 ± 4.2°. For every degree of knee joint IE rotation, TT-TG distance changed by 0.52 mm. CONCLUSION: TT-TG distance was linearly dependent on knee joint IE rotation changing by 0.52 mm for every degree of knee joint IE rotation. Thus, an offset of IE rotation of 10° would lead to a change in TT-TG distance of 5.2 mm, enough to alter surgical decision-making for/or against tibial tubercle medialization. LEVEL OF EVIDENCE: IV: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Development and validation of a biomechanically fidelic surgical training knee model.

Knee arthroplasty technique is constantly evolving and the opportunity for surgeons to practice new techniques is currently highly dependent on the availability of cadaveric specimens requiring certified facilities. The high cost, limited supply, and heterogeneity of cadaveric specimens has increased the demand for synthetic training models, which are currently limited by a lack of biomechanical fidelity. Here, we aimed to design, manufacture, and experimentally validate a synthetic knee surgical training model which reproduces the flexion dependent varus-valgus (VV) and anterior-posterior (AP) mechanics of cadaveric knees, while maintaining anatomic accuracy. A probabilistic finite element modeling approach was employed to design physical models to exhibit passive cadaveric VV and AP mechanics. Seven synthetic models were manufactured and tested in a six-degree-of-freedom hexapod robot. Overall, the synthetic models exhibited cadaver-like VV and AP mechanics across a wide range of flexion angles with little variation between models. In the extended position, two models showed increased valgus rotation (<0.5°), and three models showed increased posterior tibial translation (<1.7 mm) when compared to the 95% confidence interval (CI) of cadaveric measurements. At full flexion, all models showed VV and AP mechanics within the 95% CI of cadaveric measurements. Given the repeatable mechanics exhibited, the knee models developed in this study can be used to reduce the current reliance on cadaveric specimens in surgical training.

Developing a Machine-Learning Predictive Model for Retention of Posterior Cruciate Ligament in Patients Undergoing Total Knee Arthroplasty.

OBJECTIVE: Predicting whether the posterior cruciate ligament (PCL) should be preserved during total knee arthroplasty (TKA) procedures is a complex task in the preoperative phase. The choice to either retain or excise the PCL has a substantial effect on the surgical outcomes and biomechanical integrity of the knee joint after the operation. To enhance surgeons' ability to predict the removal and retention of the PCL in patients before TKA, we developed machine learning models. We also identified significant feature factors that contribute to accurate predictions during this process. METHODS: Patients' data on TKA continuously performed by a single surgeon who had intended initially to undergo implantation of cruciate-retaining (CR) prostheses was collected. During the sacrifice of PCL, we utilized anterior-stabilized (AS) tibial bearings. The dataset was split into CR and AS categories to form distinct groups. Relevant information regarding age, gender, body mass index (BMI), the affected side, and preoperative diagnosis was extracted by reviewing the medical records of the patients. To ensure the authenticity of the research, an initial step involved capturing X-ray images before the surgery. These images were then analyzed to determine the height of the medial condyle (MMH) and lateral condyle (LMH), as well as the ratios between MLW and MMH and MLW and LMH. Additionally, the insall-salvati index (ISI) was calculated, and the severity of any varus or valgus deformities was assessed. Eight machine-learning methods were developed to predict the retention of PCL in TKA. Risk factor analysis was performed using the SHApley Additive exPlanations method. RESULTS: A total of 307 knee joints from 266 patients were included, among which there were 254 females and 53 males. A stratified random sampling technique was used to split patients in a 70:30 ratio into a training dataset and a testing dataset. Eight machine-learning models were trained using data feeding. Except for the AUC of the LGBM Classifier, which is 0.70, the AUCs of other machine learning models are all lower than 0.70. In importance-based analysis, ISI, MMH, LMH, deformity, and age were confirmed as important predictive factors for PCL retention in operations. CONCLUSION: The LGBM Classifier model achieved the best performance in predicting PCL retention in TKA. Among the potential risk factors, ISI, MMH, LMH, and deformity played essential roles in the prediction of PCL retention.