Revision knee arthroplasty using a modular system manufactured in Brazil. Clinical and radiographic results with a mean nine-year follow-up.

OBJECTIVE: To demonstrate the clinical and radiographic results of revision knee arthroplasty using a modular system manufactured in Brazil. METHODS: Between November 2010 and January 2017, 31 revision knee arthroplasties were performed in 30 patients, using the MB-V system. Patients were assessed clinically and radiographically after a minimum follow-up of two years using the following scores: Knee Society Score (KSS), Knee Society Score ‒ Function (KSS ‒ Function), and Knee Society Roentgenographic Evaluation System (KSRES). RESULTS: Among the patients, 19 were women. The mean age at surgery was 68 years. The mean follow-up was 9.1 years. There was no aseptic loosening in this period. The mean values of KSS, KSS-function, and KSRES were, respectively, 82, 77, and less than 4. One patient evolved with postoperative flexion instability. Two knees became infected, requiring the removal of the prosthesis and implantation of spacers loaded with antibiotics. One patient developed arthrofibrosis. One patient had a dislocation with full medial collateral avulsion and had to be re-operated with an insert exchange to a CCK liner and medial collateral reconstruction as proposed by Krakow. CONCLUSION: This implant had 93.5 % survivorship (no cases of aseptic failure) and good results in 27 out of 31 knees (87 % of the surgeries).

Demographic characteristics and clinical-radiological correlation in patients with indications for Total Knee Arthroplasty: A cross-sectional study.

OBJECTIVE: The objective of this study is to correlate clinical symptoms and functionality, using the KOOS (Knee Injury and Osteoarthritis Outcome Score) and KSS (Knee Society Score System) scores, with the radiographic changes, using the Kellgren-Lawrence classification, in patients with knee osteoarthritis and indications for Total Knee Arthroplasty (TKA). METHODS: 120 patients (189 knees) with gonarthrosis and indications for TKA were included in the study. Demographic questionnaires were applied, and clinical and functional assessment was carried out using the KOOS and KSS scores. Knee radiographs were taken and graded according to Kellgren-Lawrence. The clinical scores were compared with the radiographic classification to establish a correlation between these two measurements. Statistical analysis was performed using the τ-Kendall correlation test. RESULTS: Weak and inversely proportional correlations were found between the clinical scores and the radiographic classification. Among clinical scores evaluated, KSS showed the highest correlation with Kellgren-Lawrence classification (τ = -0.356; p < 0.001), followed by KOOS-quality of life (τ = -0.176; p = 0.004), KOOS-total score (τ = -0.166; p = 0.004), KOOS-function in daily living (τ = -0.160; p = 0.005) and KOOS-symptoms (τ = -0.159; p = 0.006). KOOS-pain (τ = -0.149; p = 0.01) and KOOS-sport and recreation function (τ = -0.142; p = 0.025) scores had the weakest correlations. CONCLUSION: There is a weak correlation between the clinical-functional scores of TKA candidates and their radiographic classification by Kellgren-Lawrence. Among clinical scores evaluated, KSS had the strongest negative correlation with the radiographic classification.

Functional and radiological outcomes of total knee arthroplasty using posterior-stabilized U2 knee system: A retrospective study in 560 cases at five years of follow-up.

PURPOSE: The purpose of this study was to assess clinical and functional outcomes as well as the prosthesis survival rates of the U2 Knee system in primary total knee arthroplasty (TKA) with a minimum follow-up of four years. METHODS: We retrospectively analyzed 560 consecutively primary TKA performed between 2015 and 2019 due to osteoarthritis with a mean follow-up of 5.4 ± 1.1 years. The clinical outcomes were assessed using the knee society score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic outcomes were assessed using the American knee society's roentgenographic evaluation system. Prosthetic survival was calculated using the Kaplan-Meier method. RESULTS: Postoperative KSS showed significant improvement at one year (Clinical: 37.4 ± 4.1 vs. 91.9 ± 3.7; p < 0.01; Functional: 41.2 ± 3.3 vs. 90.6 ± 4.8; p = < 0.01), with these improvements maintained throughout the follow-up period. The WOMAC score improved from 60 ± 10.1 preoperatively to 10.9 ± 8.3 (p = 0.02) at the end of the follow-up. There were 20 (3.7%) knees with radiolucent lines around the implant (< 2 mm), and none showed evidence of loosening. There were six (1.1%) revisions-four due to prosthetic joint infections and two due to periprosthetic femur fracture. The prosthetic survival was 97.8% at the study closure. CONCLUSION: The U2 knee system demonstrates effective and safe performance for primary TKA with significant improvements in functional scores, patient-reported outcomes, and a promising prosthesis survival rate at mid-term follow-up. We will continue with the series analysis to assess the long-term outcomes.

Is there a relationship between knee crepitus with quadriceps muscle thickness and strength in individuals with patellofemoral pain? A cross-sectional study.

OBJECTIVE: To explore the relationship between knee crepitus, quadriceps muscle thickness and isometric strength in individuals with patellofemoral pain (PFP). DESIGN: Cross-sectional. PARTICIPANTS: Individuals with PFP. MAIN OUTCOME MEASURES: Participants with PFP underwent assessments for presence, frequency and severity of knee crepitus. Real-time ultrasound images of the quadriceps muscles (rectus femoris, vastus medialis and lateralis) at rest and during contraction were obtained, muscle thickness was measured in both conditions. Maximal voluntary isometric contraction tests were performed to measure knee extensor strength. The relationship between knee crepitus and quadriceps muscle thickness and knee extensor strength was explored using logistic and linear regressions. RESULTS: Sixty individuals with PFP were included (age: 24; 60% women; 38% with crepitus). Knee crepitus severity was related to rectus femoris and vastus medialis thickness during rest (R2 = 0.19 and 0.09, respectively) and contraction (R2 = 0.16 and 0.07, respectively) and with vastus lateralis during contraction (R2 = 0.08). Isometric knee extensor strength was not related to knee crepitus presence, frequency, or severity. CONCLUSION: Higher severity of knee crepitus is related to lower quadriceps muscle thickness in individuals with PFP. There is no relationship between the presence and frequency of knee crepitus with quadriceps muscle thickness or knee extensor strength.

Enhancing robotic precision in medial UKA: Image-based robot-assisted system had higher accuracy in implant positioning than imageless robot-assisted system across 292 knees.

PURPOSE: The objective of this study was to compare the degree of accuracy in implant positioning and limb alignment offered by two robot-assisted (RA) systems: an image-based robot-assisted (IBRA) versus an imageless robot-assisted (ILRA) system for the treatment of medial knee osteoarthritis with unicompartmental knee arthroplasty (UKA). METHODS: This retrospective radiographic study included medial UKAs performed between 2011 and 2023. Radiographic measurements taken preoperatively and at 1-year postoperative control visit focusing on hip-knee-ankle angle (HKA), posterior tibial slope (PTS), tibial component coronal alignment relative to Cartier's angle and restoration of proper joint line (JL) height were analyzed. Outliers for postoperative measurements were defined as follows: HKA <175° or >180°, PTS <2° or >8°, >3° or <-3° alterations in Cartier's angle and ±2 mm changes in the height of the joint line. RESULTS: The final sample consisted of 292 medial UKAs: 95 (32.5%) with an IBRA system and 197 (67.5%) with an ILRA system. Implant positioning and limb alignment were more accurate in the group of patients treated with IBRA, HKA (77.9% vs. 67.5%, p = 0.07), PTS (93.7% vs. 82.7%, p = 0.01), restoration of tibial varus relative to Cartier's angle (87.4% vs. 65%, p < 0.001) and restoration of JL height (81.1% vs. 69.5%, p = 0.04). CONCLUSION: Medial UKA surgery using an IBRA system was associated with a higher degree of accuracy in implant positioning and postoperative limb alignment as compared to an ILRA system. This is a valuable contribution to help communicate the advantages of using this surgical technique and improve its reproducibility. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

Machine learning-based bioimpedance assessment of knee osteoarthritis severity.

This study proposes a multiclass model to classify the severity of knee osteoarthritis (KOA) using bioimpedance measurements. The experimental setup considered three types of measurements using eight electrodes: global impedance with adjacent pattern, global impedance with opposite pattern, and direct impedance measurement, which were taken using an electronic device proposed by authors and based on the Analog Devices AD5933 impedance converter. The study comprised 37 participants, 25 with healthy knees and 13 with three different degrees of KOA. All participants performed 20 repetitions of each of the following five tasks: (i) sitting with the knee bent, (ii) sitting with the knee extended, (iii) sitting and performing successive extensions and flexions of the knee, (iv) standing, and (v) walking. Data from the 15 experimental setups (3 types of measurements×5 exercises) were used to train a multiclass random forest. The training and validation cycle was repeated 100 times using random undersampling. At each of the 100 cycles, 80% of the data were used for training and the rest for testing. The results showed that the proposed approach achieved average sensitivities and specificities of 100% for the four KOA severity grades in the extension, cyclic, and gait tasks. This suggests that the proposed method can serve as a screening tool to determine which individuals should undergo x-rays or magnetic resonance imaging for further evaluation of KOA.

Tratamiento de la contractura en flexión de rodilla en parálisis cerebral / Treatment for knee flexion contracture in cerebral palsy

La extensión completa de la rodilla es esencial para la marcha. Los pacientes con parálisis cerebral infantil con frecuencia pueden tener déficit de extensión de distinta magnitud, lo que compromete la marcha e incluso la bipedestación. El tratamiento de la contractura en flexión de rodilla parte por tratar la espasticidad de los músculos comprometidos y con fisioterapia. Cuando el flexo es estructurado, el tratamiento es quirúrgico mediante distintas técnicas, dependiendo de la magnitud de la contractura y de la edad del paciente. Las técnicas sobre partes blandas incluyen alargamientos funcionales de isquiotibiales y transferencias musculares. Cuando la contractura es capsular, es preferible realizar cirugía ósea, la cual extiende el fémur proximal, ya sea en forma progresiva, mediante fisiodesis anterior en pacientes pediátricos, o en forma aguda, mediante osteotomía extensora del fémur distal. Con frecuencia existe una patela alta, la cual hay que corregir en el mismo acto quirúrgico para mantener la eficiencia del aparato extensor

Full knee extension is essential for gait. Patients with cerebral palsy frequently have extension deficits of different magnitudes, which compromise walking and even standing up. The treatment of knee flexion contracture begins by addressing the spasticity of the involved muscles and includes physical therapy. For structured extension deficits, the treatment is surgical, using different techniques depending on the magnitude of the contracture and the patient's age. Soft tissue techniques include functional hamstring lengthening and muscle transfers. For capsular contracture, bone surgery is preferable and extends the proximal femur either progressively, through anterior physiodesis in pediatric patients, or acutely, by extensor distal femoral osteotomy. A high patella is common and requires correction during the same surgical procedure to maintain the efficiency of the extensor apparatus

Development of a Machine-Learning Model for Anterior Knee Pain After Total Knee Arthroplasty With Patellar Preservation Using Radiological Variables.

BACKGROUND: Anterior knee pain (AKP) following total knee arthroplasty (TKA) with patellar preservation is a common complication that significantly affects patients' quality of life. This study aimed to develop a machine-learning model to predict the likelihood of developing AKP after TKA using radiological variables. METHODS: A cohort of 131 anterior stabilized TKA cases (105 patients) without patellar resurfacing was included. Patients underwent a follow-up evaluation with a minimum 1-year follow-up. The primary outcome was AKP, and radiological measurements were used as predictor variables. There were 2 observers who made the radiological measurement, which included lower limb dysmetria, joint space, and coronal, sagittal, and axial alignment. Machine-learning models were applied to predict AKP. The best-performing model was selected based on accuracy, precision, sensitivity, specificity, and Kappa statistics. Python 3.11 with Pandas and PyCaret libraries were used for analysis. RESULTS: A total of 35 TKA had AKP (26.7%). Patient-reported outcomes were significantly better in the patients who did not have AKP. The Gradient Boosting Classifier performed best for both observers, achieving an area under the curve of 0.9261 and 0.9164, respectively. The mechanical tibial slope was the most important variable for predicting AKP. The Shapley test indicated that high/low mechanical tibial slope, a shorter operated leg, a valgus coronal alignment, and excessive patellar tilt increased AKP risk. CONCLUSIONS: The results suggest that global alignment, including sagittal, coronal, and axial alignment, is relevant in predicting AKP after TKA. These findings provide valuable insights for optimizing TKA outcomes and reducing the incidence of AKP.

Assessment of knee instability in ACL-injured knees using weight-bearing computed tomography (WBCT): a novel protocol and preliminary results.

OBJECTIVE: To propose a protocol for assessing knee instability in ACL-injured knees using weight-bearing computed tomography (WBCT). MATERIALS AND METHODS: We enrolled five patients with unilateral chronic ACL tears referred for WBCT. Bilateral images were obtained in four positions: bilateral knee extension, bilateral knee flexion, single-leg stance with knee flexion and external rotation, and single-leg stance with knee flexion and internal rotation. The radiation dose, time for protocol acquisition, and patients' tolerance of the procedure were recorded. A blinded senior radiologist assessed image quality and measured the anterior tibial translation (ATT) and femorotibial rotation (FTR) angle in the ACL-deficient and contralateral healthy knee. RESULTS: All five patients were male, aged 23-30 years old. The protocol resulted in a 16.2 mGy radiation dose and a 15-min acquisition time. The procedure was well-tolerated, and patient positioning was uneventful, providing good-quality images. In all positions, the mean ATT and FTR were greater in ACL-deficient knees versus the healthy knee, with more pronounced differences observed in the bilateral knee flexion position. Mean lateral ATT in the flexion position was 9.1±2.8 cm in the ACL-injured knees versus 4.0±1.8 cm in non-injured knees, and mean FTR angle in the bilateral flexion position was 13.5°±7.7 and 8.6°±4.6 in the injured and non-injured knees, respectively. CONCLUSION: Our protocol quantitatively assesses knee instability with WBCT, measuring ATT and FTR in diverse knee positions. It employs reasonable radiation, is fast, well-tolerated, and yields high-quality images. Preliminary findings suggest ACL-deficient knees show elevated ATT and FTR, particularly in the 30° flexion position.

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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Structural and functional brain changes in people with knee osteoarthritis: a scoping review.

Background: Knee osteoarthritis is a highly prevalent disease worldwide that leads to functional disability and chronic pain. It has been shown that not only changes are generated at the joint level in these individuals, but also neuroplastic changes are produced in different brain areas, especially in those areas related to pain perception, therefore, the objective of this research was to identify and compare the structural and functional brain changes in knee OA versus healthy subjects. Methodology: Searches in MEDLINE (PubMed), EMBASE, WOS, CINAHL, SCOPUS, Health Source, and Epistemonikos databases were conducted to explore the available evidence on the structural and functional brain changes occurring in people with knee OA. Data were recorded on study characteristics, participant characteristics, and brain assessment techniques. The methodological quality of the studies was analysed with Newcastle Ottawa Scale. Results: Sixteen studies met the inclusion criteria. A decrease volume of the gray matter in the insular region, parietal lobe, cingulate cortex, hippocampus, visual cortex, temporal lobe, prefrontal cortex, and basal ganglia was found in people with knee OA. However, the opposite occurred in the frontal lobe, nucleus accumbens, amygdala region and somatosensory cortex, where an increase in the gray matter volume was evidenced. Moreover, a decreased connectivity to the frontal lobe from the insula, cingulate cortex, parietal, and temporal areas, and an increase in connectivity from the insula to the prefrontal cortex, subcallosal area, and temporal lobe was shown. Conclusion: All these findings are suggestive of neuroplastic changes affecting the pain matrix in people with knee OA.

Magnetic resonance imaging of the knee anteromedial quadrant.

OBJECTIVE: This study aims to evaluate the possibility of characterizing an extra-articular thickening in the knee anteromedial quadrant in routine MRI scans. MATERIALS AND METHODS: Firstly, in a pilot study, for a better understanding of this extra-articular thickening trajectory in MRI, polytetrafluoroethylene (PTFE) tubes were attached to the ligament structure topography in two dissected pieces. Afterward, 100 knee MRI studies were randomly selected from our database, and 97 met the inclusion criteria. Two musculoskeletal radiologists interpreted the exams separately. Both had previously studied the ligament in the cadaveric knee MRI with the PTFE tube. RESULTS: The intraobserver and interobserver agreement for the ligament identification was calculated using Cohen's Kappa coefficient. The first radiologist identified the structure in 41 of the 97 scans (42.2%), and the second radiologist in 38 scans (39.2%). The interobserver agreement was substantial, with a Kappa of 0.68 and an agreement of 84.5%. The results suggest that this extra-articular thickening, recently called Anterior Oblique Ligament (AOL) in the literature, is a structure that can be frequently visualized on MRI scans with a high level of interobserver agreement in a relatively large number of exams. CONCLUSION: Therefore, this study indicates that MRI is a promising method for evaluating this anteromedial thickening, and it may be used for future studies of the Anterior Oblique Ligament.

Anterolateral ligament MRI of the knee in ACL injuries: MRI abnormalities association with instability.

OBJECTIVE: To evaluate anterolateral ligament abnormalities (ALL) at MRI scans and correlate with data from clinical instability tests (Lachman and pivot shift) performed under anesthesia in patients with acute anterior cruciate ligament (ACL) tears. Furthermore, perform multivariate analysis with other variables to isolate the ALL contribution to instability from other abnormalities. METHODS: Retrospective analysis of MRI and instability tests of 95 patients with ACL tears. The ALL was classified as no abnormality, abnormality without discontinuity, and discontinuity. Injuries in other knee ligament structures and menisci were also assessed. Results of instability tests (pivot shift and Lachman) with the patient anesthetized for arthroscopic ACL reconstruction were obtained from the patient database. Statistical analysis was performed using the IBM SPSS 22. RESULTS: ALL abnormalities and iliotibial band (ITB), lateral (LCL), and medial (MCL) collateral ligament injuries showed a statistically significant correlation with the pivot shift test. The ALL MRI abnormalities were associated with the high-grade pivot shift results (p < 0.0005), with an odds ratio of 55.9 for high degrees of pivot shift in patients with abnormal ALL. The logistic model for all variables analyzed with the results of the pivot shift test demonstrated that the ALL was the only variable with a statistically significant correlation in the model (p < 0.0005). CONCLUSION: MRI ALL abnormalities in patients with ACL injuries have a significant association with pivot shift test results in patients under anesthesia. The logistic model for high - grade pivot shift test results demonstrated that ALL abnormalities were the only variable with significant correlation. KEY POINTS: • Evaluating the anterolateral ligament with MRI in acute anterior cruciate ligament injuries is useful to predict higher grades of pivot shift test in the moment of the arthroscopic reconstruction. • An abnormal anterolateral ligament presented an odds ratio of 55 for high degrees of pivot shift. • ALL MRI abnormalities association with knee instability is independent from other internal knee injuries.

Three-Dimensional Orientation of the Native Anterior Cruciate Ligament in Magnetic Resonance Imaging.

The aim of this study was to describe the three-dimensional orientation of the native anterior cruciate ligament (ACL) in magnetic resonance imaging (MRI) by calculating the angles of inclination in relation to the axial plane which is given for the knee joint line in a group of healthy individuals. These could help to establish guidelines that may be used for the surgical positioning of bone tunnels during ACL reconstruction. A total of 290 MRI scans of patients with integrity of the ACL were evaluated; three observers identified the coordinates of the femoral and tibial insertion sites, then it is defined the vector and evaluated its angles with respect to axial axis and calculated the angles with trigonometric equations. The data were analyzed according to the age, sex, side, BMI, and height of the patients, and the interobserver reliability was calculated. The patient demographics were as follows: age average: 45 years old, BMI average: 27.1, 54% right knees, and 60% female. The average angle for all the measurements was 76.95 degrees (SD ± 6.8 degrees) in the sagittal plane, 81.65 degrees (SD ± 7.79 degrees) in the coronal plane and 33.17 degrees (SD ± 4.98 degrees) in the axial plane. No statistically significant differences were found between the categorical variables mentioned; moderate to substantial interobserver reliability strength was found with an average kappa of 0.791 for all measurements. The three-dimensional orientation of the native ACL in a group of healthy individuals was established. The findings can be helpful for performing anatomical reconstructions of the ACL in injured patients using as reference the average calculated angles, or measure of the contralateral non-injured knee for surgical planning; these results serve as a basis for the design of a technique that optimizes the three-dimensional position of the ACL when it undergoes reconstruction in the trend toward greater precision for better functional results. Biomechanical and clinical-surgical studies are required to further evaluate our results.

The influence of iliotibial tract thickness on clinical outcomes in women with patellofemoral pain.

BACKGROUND: The assessment of iliotibial tract thickness by ultrasonography may help identify a key, previously unexplored factor that may contribute directly to the homeostasis imbalance of the femoropatellar joint in people with patellofemoral pain (PFP). OBJECTIVES: To compare the iliotibial tract thickness of people with PFP and asymptomatic people; and to correlate the iliotibial tract thickness with self-reported pain and function of people with PFP. METHODS: Eighty women, separated into two groups: PFP group (n = 40) and control group consisting of asymptomatic participants (CG; n = 40). The participants answered the Anterior Knee Pain Scale (AKPS) questionnaire, to identify the self-reported knee function; they evaluated the pain in millimeters by the Visual Analog Scale for pain (VAS). For the imaging evaluation, an ultrasound was used, with a linear transducer at the distal portion of the iliotibial tract (coronal plane), with the participants positioned in dorsal decubitus, with 20° of knee flexion. The iliotibial band was visualized in its long axis, and three sequential images were recorded between the lateral femoral condyle and the lateral tibial condyle. The measurements were normalized and correlated. RESULTS: The groups had no differences (P > 0.001) between participants for: age/weight/height/IMC. Participants in the PFP group had moderate levels of pain (58 + 2.1 mm), considerable self-reported functional limitation (d = 3.05) and greater iliotibial tract thickness compared with the CG (d = 2.41). CONCLUSION: The iliotibial tract of women diagnosed with PFP have greater thickness compared with asymptomatic women. There was no association between iliotibial tract thickness and subjective measures of pain and function.

Does static stretching change uniformly the quadriceps elasticity in physically actives subjects?

PURPOSE: Verify the acute responses of static stretching (SS) on the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) elasticity and knee/hip range of motion (ROM). Additionally, to investigate if there are consistency among quadriceps muscle elasticity after SS. METHODS: Acute effect of SS on pre-post-intervention design. Thirtheen healthy participants (both genders) proposed for a pre-post experimental design. RF, VM, and VL elasticity (strain ratio, SR) was evaluated bilaterally by ultrasound with quasi-static elastography. Higher SR values refer to more rigid tissues. A SS protocol of 3 series of 30 s was applied at right lower limb. The left lower limb was considered as control group. Also, photogrammetry evaluated the knee/hip ROM. RESULTS: For SR muscle comparisons, VM was lower (less stiff) than VL and RF at pre- and post-SS. For time comparisons, no differences were observed for SR and ROM at pre- and post-SS. However, the effect size of the quadriceps SR at SS lower limb was higher than control. CONCLUSION: Acute effects of SS did not change the quadriceps SR or knee/hip ROM in healthy and active subjects. Non-uniform quadriceps SR are observed (VM < VL and RF) independently of SS. Future studies should consider different protocols, muscles, and populations.

Image-Free Robotic-Assisted Total Knee Arthroplasty Improves Implant Alignment Accuracy: A Cadaveric Study.

BACKGROUND: Improving resection accuracy and eliminating outliers in total knee arthroplasty (TKA) is important to improving patient outcomes regardless of alignment philosophy. Robotic-assisted surgical systems improve resection accuracy and reproducibility compared to conventional instrumentation. Some systems require preoperative imaging while others rely on intraoperative anatomic landmarks. We hypothesized that the alignment accuracy of a novel image-free robotic-assisted surgical system would be equivalent or better than conventional instrumentation with fewer outliers. METHODS: Forty cadaveric specimens were used in this study. Five orthopedic surgeons performed 8 bilateral TKAs each, using the VELYS Robotic-Assisted System (DePuy Synthes) and conventional instrumentation on contralateral knees. Pre-resection and postresection computed tomography scans, along with optical scans of the implant positions were performed to quantify resection accuracies relative to the alignment targets recorded intraoperatively. RESULTS: The robotic-assisted cohort demonstrated smaller resection errors compared to conventional instrumentation in femoral coronal alignment (0.63° ± 0.50° vs 1.39° ± 0.95°, P < .001), femoral sagittal alignment (1.21° ± 0.90° vs 3.27° ± 2.51°, P < .001), and tibial coronal alignment (0.93° ± 0.72° vs 1.65° ± 1.29°, P = .001). All other resection angle accuracies were equivalent. Similar improvements were found in the femoral implant coronal alignment (0.89° ± 0.82° vs 1.42° ± 1.15°, P = .011), femoral implant sagittal alignment (1.51° ± 1.08° vs 2.49° ± 2.10°, P = .006), and tibial implant coronal alignment (1.31° ± 0.84° vs 2.03° ± 1.44°, P = .004). The robotic-assisted cohort had fewer outliers (errors >3°) for all angular resection alignments. CONCLUSION: This in vitro study demonstrated that image-free robotic-assisted TKA can improve alignment accuracy compared to conventional instrumentation and reduce the incidence of outliers.

Anteromedial meniscofemoral ligament-A rare finding.

We report a case of a 49-year-old patient presenting an anteromedial meniscofemoral ligament (AMMFL) on both knees with a tear of this ligament in the left knee associated to a normal anterior cruciate ligament (ACL). The AMMFL is a relatively rare anatomic structure that may correspond to a variant of the ACL type anterior root insertion of the medial meniscus. The findings reported in the literature were in most part results of incidental situations. AMMFL can be visualized through magnetic resonance imaging (MRI) and arthroscopy.

The posterior cruciate ligament inclination angle is higher in anterior cruciate ligament insufficiency.

PURPOSE: Magnetic resonance imaging (MRI) is the gold standard image examination for anterior cruciate ligament (ACL) lesion diagnosis. Our hypothesis was that measuring the posterior cruciate ligament inclination angle (PCLIA) using MRI images may be an auxiliary tool to aid the recognition of ACL insufficiency. The purpose of this study was to compare the PCLIA measurement in MRIs of individuals with and without ACL injury. METHODS: The PCLIA was measured by two radiologists in 65 knee MRIs of patients with intact ACL (control group) and in 65 knee MRIs of people with ACL injury (study group). In both groups, the posterior cruciate ligament was intact. The control group was included 35 men (53.8%) and 30 women (46.1%). The patients' average age was 38.7 years (range 15-75; SD ± 14.8 years). In this group, 31 (47.6%) MRIs were from right knees and 34 (52.3%) were from left knees. The study group consisted of 45 men (69.2%) and 20 women (30.7%). The patients' average age was 36.8 years (range 14-55; SD ± 10.3 years). In this group, 33 (50.7%) were right knees and 32 (49.2%) were left knees. PCLIA was formed by the intersection of two lines drawn in MRI sagittal images. The first passed tangentially to the articular surface of the tibial condyle and the second was drawn over the fraction of the ligament that originated where the first crossed the PCL, outlined proximally. RESULTS: The average PCLIA was 44.2 ± 3.8° in the control group and 78.9 ± 8.6° in the study group. Statistical analyses showed that the PCLIA was higher in the group with ACL injury (p < 0.05). Conclusion The PCLIA was significantly higher in individuals with ACL injuries. The measurement of this angle using MRI images may allow for detection of ACL insufficiency and thus assist in an individualized and precise approach to the treatment of injuries to the ACL. CLINICAL RELEVANCE: PCLIA may be a way to detect ACL insufficiency and thus help surgeons to decide which patient might need ACL reconstruction. LEVEL OF EVIDENCE: III.