Quadriceps muscle contraction causes medial patellofemoral ligament elongation by intermeshed fibers of vastus medialis oblique muscle.

The first aim of this study was to compare the medial patellofemoral length between contracted and relaxed quadriceps muscle and second to assess the importance of the intermeshed vastus medialis oblique fibers. After a priori power analysis (α = 0.05, power [1-ß] = 0.95), 35 healthy males aged 18-30 were prospectively examined with a 3.0-T magnetic resonance imaging (MRI) scanner in 10-15° of knee flexion. Two axial MRI sequences (25 s each) were made with relaxed and contracted quadriceps. Two blinded, independent raters measured twice medial patellofemoral ligament length (curved line) and attachment-to-attachment length (straight line). Mean medial patellofemoral ligament length and attachment-to-attachment length with relaxed quadriceps was: 65.5 mm (SD = 3.7), 59.7 mm (SD = 3.6), and after contraction, it increased to 68.7 mm (SD = 5.3), 61.2 mm (SD = 4.7); p < 0.01 and <0.001, respectively. Intraclass correlation coefficients for intra- and inter-rater reliabilities ranged from 0.55 (moderate) to 0.97 (excellent). Mean medial patellofemoral ligament length elongation after quadriceps contraction was significantly greater (3.2 mm, SD = 3.9) than mean attachment-to-attachment length elongation (1.6 mm, SD = 2.8); p < 0.001. Contraction of quadriceps muscle causes elongation of the medial patellofemoral ligament to the extent greater than the elongation of distance between its attachments. This confirms that medial patellofemoral ligament elongation after quadriceps contraction results not only from movement of its patellar attachment but also directly from intermeshed vastus medialis oblique fibers pulling medial patellofemoral ligament in a different direction creating a bow-like construct in agreement with the "pull-and-guide mechanism" proposed in the literature.

The effect of high-intensity laser therapy on pain and lower extremity function in patellofemoral pain syndrome: a single-blind randomized controlled trial.

Patellofemoral pain syndrome (PFPS) is a set of symptoms that negatively affect the daily life activities of the individual, leading to functional disability and significant loss of labor, especially in young adults. PFPS is usually due to weakness of the vastus medialis obliquus (VMO) resulting in abnormal patellar tracking and pain. Our study aims to compare the efficacy of high-intensity laser therapy (HILT) on pain and lower extremity function in the treatment of PFPS with different electrophysical agents (EPAs). The study was designed as a single-blind randomized controlled trial. Forty-five people with PFPS (aged 25-45 years) were included in the study. The patients were randomly divided into three groups and a total of ten sessions of treatment were administered to all three groups for 2 weeks, 5 days a week. High-intensity laser (HILT) and exercise program were applied to group 1. Ultrasound (US), transcutaneous electrical nerve stimulation (TENS), and exercise program were applied to group 2. In group 3, US, interferential current (IFC), and exercise program were applied. Both groups underwent three evaluations: pre-treatment, post-treatment, and 12 weeks after treatment. Outcome measures included the visual analog scale for pain severity (VAS), knee flexion range of motion (FROM), Q angle, pain threshold, muscle strength of quadriceps and hamstring, Kujala patellofemoral scoring, lower extremity functional scale (LEFS), and Timed Up and Go Test (TUG). The ANOVA was used for comparing the data of the groups, and two-way repeated measure ANOVA was used to compare at the pre-post and post-intervention 3rd month. The LSD and Bonferroni post hoc tests were also used to identify the between-group differences. Groups 2 and 3 were statistically effective in pain and functionality (p < 0.05). Group 1 was found to be statistically more effective than other groups in reducing pain (95% confidence interval (CI), 0.000/0.000; p = 0.000), increasing knee flexion angle (95% CI, 127.524/135.809; p = 0.000), and increasing lower extremity function (95% CI, 75.970/79.362; p = 0.000). This study indicated that high-intensity laser therapy was found to be a more effective method in the treatment of patellofemoral pain syndrome after 3 months of follow-up compared to US-TENS combination and US-interferential current combination treatments. Also, HILT can be used as an effective method in combination with an appropriate exercise program including vastus medialis strengthening to reduce pain and increase functionality in the patients with PFPS.

Differential influence of quadriceps rate of torque development on single- and double-leg landing mechanics in anterior cruciate ligament reconstructed and control females.

PURPOSE: The capacity to explosively contract quadriceps within the critical timeframe associated with anterior cruciate ligament (ACL) injury, quantified by the rate of torque development, is potentially essential for safe landing mechanics. This study aimed to investigate the influence of explosive quadriceps strength on ACL-related sagittal-plane landing mechanics in females with and without ACL reconstruction (ACLR). METHODS: Quadriceps explosive strength and landing mechanics were assessed in 19 ACLR and 19 control females during isometric contractions and double- and single-leg jump landings. A stepwise multiple linear regression model determined the variance in each of the landing biomechanics variables for the ACLR limb and nondominant limb of controls that could be explained by the group, rate of torque development and/or their interaction. If peak kinetic variables could be predicted by the rate of torque development or interaction, additional analyses were conducted, accounting for knee flexion as a covariate in the regression model. RESULTS: During single-leg landings, ACLR females exhibited greater knee flexion at initial contact than controls (p = 0.04). Greater quadriceps rate of torque development predicted higher peak posterior ground reaction force and anterior tibial shear force in both groups (p = 0.04). However, after controlling for knee flexion angle at those peak forces, quadriceps rate of torque development was not predictive. In double-leg landings, greater explosive quadriceps strength was associated with quicker attainment of peak knee extension moment and posterior ground reaction force in the ACLR limb (p = 0.03). CONCLUSION: Regardless of ACL injury status, females with greater explosive quadriceps strength adopted safer single-leg landings through increased knee flexion, potentially mitigating ACL loading despite encountering higher peak forces. During double-leg landings, a greater explosive quadriceps strength of the ACLR limb is associated with faster achievement of peak force upon landing. Incorporating explosive quadriceps strengthening into post-ACLR rehabilitation and injury prevention programmes may enhance landing mechanics for reducing primary and subsequent ACL injury risks. LEVEL OF EVIDENCE: Level II.

Sex differences in skeletal muscle fiber types: A meta-analysis.

Biopsies have been acquired from living men and women to determine proportions of Type I (slow-twitch) and II (fast-twitch) skeletal muscle fibers since the 1970s. Sex differences have been assumed but the literature has not been submitted to meta-analysis. Here, the aim was to generate effect sizes of sex differences in muscle fiber cross-sectional areas, distribution percentages, and area percentages. Data from 2875 men and 2452 women, who participated in 110 studies, were analyzed. Myofibrillar adenosine triphosphatase histochemistry was used in 71.8% of studies to classify fibers as Type I, II, IIA, and/or IIX; immunohistochemistry, immunofluorescence, or sodium dodecyl sulfate-polyacrylamide gel electrophoresis were used in 35.4% of studies to similarly classify myosin heavy chain (MHC) isoform content. Most studies involved biopsies from vastus lateralis (79.1%) in healthy individuals (92.7%) between 18 and 59 years old (80.9%). Men exhibited greater cross-sectional areas for all fiber types (g = 0.40-1.68); greater distribution percentages for Type II, MHC II, IIA, IIX fibers (g = 0.26-0.34); greater area percentages for Type II, IIA, MHC IIA, IIX fibers (g = 0.39-0.93); greater Type II/I and Type IIA/I fiber area ratios (g = 0.63, 0.94). Women exhibited greater Type I and MHC I distribution percentages (g = -0.13, -0.44); greater Type I and MHC I area percentages (g = -0.53, -0.69); greater Type I/II fiber area ratios (g = -1.24). These data, which represent the largest repository of comparative muscle fiber type data from living men and women, can inform discussions about biological sex and its impact on pathologies and sports performance (e.g., explaining sex differences in muscle strength and muscle endurance).

Post-Activation-Performance Enhancement: Possible Contributing Factors.

This study aimed to narrow down the possible mechanisms of Post-Activation Performance Enhancement (PAPE), especially if they are exclusively found in the muscle. It was therefore investigated whether (1) the PAPE effect is influenced by neural factors and (2) if Post-Activation-Potentiation (PAP) influences PAPE. Thirteen strength-trained participants (26.5 ± 3.2 years) took part in at least one of three interventions (PAP, PAPE-Electrical (PAPEE), and PAPE-Voluntary (PAPEV)). Conditioning contractions (CC) and testing involved isometric knee extensions performed on an isokinetic device at an 80° knee flexion angle. The CC was either performed voluntarily (PAP, PAPEV) or was evoked through electrical stimulation (PAPEE). Testing was performed at baseline and after two seconds, four minutes, eight minutes, and twelve minutes of the CC. Maximum voluntary isometric contractions (MVIC) for the PAPE trials and supramaximal twitches for the PAP trial were used for testing. Parameters of interest were peak torque and rate of torque development (RTD), and electromyography (EMG) amplitude of the quadriceps (only PAPE). Repeated measures ANOVA and simple contrast comparisons were used for statistical analysis. Peak torque (p < 0.001, η2p = 0.715) and RTD (p = 0. 005, η2p = 0.570) increased significantly during the PAP protocol immediately two seconds after the CC and decreased to near baseline values for the following time points (p > 0.05). Peak torque, RTD, and peak EMG showed no significant differences during PAPEE and PAPEV trials (p > 0.05). Due to the lack of a visible PAPE effect, the question of whether neural mechanisms influence PAPE cannot be answered. Due to the time course of the PAP analysis, it is questionable if these mechanisms play a role in PAPE. The assumption that the PAP mechanism influences PAPE cannot be confirmed for the same reason.

An Observational Study of Nutritional Assessment, Prescription, Practices, and Its Outcome among Critically Ill Patients Admitted to an Intensive Care Unit.

Aim and background: Optimal feeding strategy for critically ill patients of intensive care unit (ICU) is often a matter of debate as patients admitted to ICU are highly catabolic and reduction in muscle mass is very common. We aimed at early achievement of nutritional goals in preventing skeletal muscle breakdown and improving clinical outcomes among critically ill patients with high risk of malnutrition. Materials and methods: Nutrition risk in the critically ill (mNUTRIC) Score was used to identify the risk of malnutrition within 24 hours of admission. Quadriceps muscle mass index was measured within 24 hours of admission to ICU and repeated on 7th day. Enteral feeding was monitored by the nutrition expert as part of routine patient care and clinical outcomes were monitored. Results: A total of 287 patients admitted in ICU were screened for malnutrition and 60 (20.9%) of them had high score (>5). There was no statistically significant reduction in the quadriceps muscle mass index (p < 0.05) (t = 0.601) measured within 24 hours of admission and on the 7th day of ICU stay, signifying that the nutritional prescription and monitoring may be useful in preserving the muscle mass. This study did not find statistically significant association between the high mNUTRIC score on admission and the clinical outcomes, such as 28 days mortality, incidence of pressure ulcers, length of ICU stay, and hospital-acquired infection (p > 0.05). Conclusion: Early initiation and maintenance of enteral nutrition is essential for meeting target calories and protein requirements. It may help to preserve muscle mass in critically ill patients who are otherwise at high risk of malnutrition. How to cite this article: Sharon T, Nayak SG, Shanbhag V, Hebbar S. An Observational Study of Nutritional Assessment, Prescription, Practices, and Its Outcome among Critically Ill Patients Admitted to an Intensive Care Unit. Indian J Crit Care Med 2024;28(4):364-368.

Comparison between Effect of Indirect Calorimetry vs Weight-based Equation (25 kcal/kg/day)-guided Nutrition on Quadriceps Muscle Thickness as Assessed by Bedside Ultrasonography in Medical Intensive Care Unit Patients: A Randomized Clinical Trial.

Aim and background: Sarcopenia is a substantial contributor to intensive care unit (ICU)-acquired weakness and is associated with significant short- and long-term outcomes. It can, however, be mitigated by providing appropriate nutrition. Indirect calorimetry (IC) is believed to be the gold standard in determining caloric targets in the dynamic environment of critical illness. We conducted this study to compare the effect of IC vs weight-based (25 kcal/kg/day) feeding on quadriceps muscle thickness (QMT) by ultrasound in critically ill patients. Materials and methods: A prospective study was conducted on 60 mechanically ventilated patients randomized to two groups [weight-based equation (WBE) group or the IC group] in medical ICU after obtaining institutional ethics committee approval, and fed accordingly. The right QMT measurement using ultrasound and caloric targets were documented on day 1, 3 and 7 and analyzed statistically. The IC readings were obtained from the metabolic cart E-COVX ModuleTM. Results: The baseline demographics, APACHE-II, NUTRIC score, and SOFA scores on day 1, 3, and 7 were comparable between the two groups. The resting energy expenditure (REE) obtained in the IC group was significantly less than the WBE energy targets and the former were fed with significantly less calories. A significantly less percent reduction of QMT in the IC group compared with the WBE group was observed from day 1 to day 3, day 3 to day 7, and day 1 to day 7. Conclusion: From our study, we conclude that IC-REE-based nutrition is associated with lesser reduction in QMT and lesser calories fed in critically ill mechanically ventilated patients compared from WBE. CTRI registration-CTRI/2023/01/049119. How to cite this article: Chandrasekaran A, Pal D, Harne R, Patel SJ, Jagadeesh KN, Pachisia AV, et al. Comparison between Effect of Indirect Calorimetry vs Weight-based Equation (25 kcal/kg/day)-guided Nutrition on Quadriceps Muscle Thickness as Assessed by Bedside Ultrasonography in Medical Intensive Care Unit Patients: A Randomized Clinical Trial. Indian J Crit Care Med 2024;28(6):587-594.

Accuracy of a portable lower-limb muscle strength measuring device with a training function.

[Purpose] Quadriceps muscle strength is essential for daily living activities. Therefore, we developed a compact and simple lower limb muscle strength measuring device (LocomoScan [LCS]). This study aimed to compare LCS with other instruments to analyze its simplicity, reproducibility, and accuracy. [Participants and Methods] One hundred and four healthy university students (56 males and 48 females) were included in the study. The knee extension force was measured using LCS, and the knee extension torque was measured using other devices (Cybex). In addition, lower leg muscle mass was measured using a body composition meter. The reproducibility of LCS and the correlation between the knee extension torque and lower leg muscle mass were evaluated. [Results] The measurement reproducibility of LCS was significantly higher. The knee extension force confirmed the proportional relative reliability of Cybex with knee extension torque. A relationship between knee extension force and lower limb muscle mass was also observed, indicating that muscle mass cannot be estimated as muscle strength. [Conclusion] The high reproducibility of the knee extension force measurement using LCS demonstrates its potential as a portable alternative instrument for muscle strength measurement in clinical practice. Therefore, LCS device is a simple and effective tool for assessing muscle strength.

Utility of muscle ultrasound in nutritional assessment of children with nephrotic syndrome.

BACKGROUND: Nutritional status assessment in children with nephrotic syndrome (NS) is critical for identifying patients who are at risk of protein-energy wasting (PEW) and for determining their nutritional needs and monitoring nutritional intervention outcomes. METHODS: In a case-control study, we enrolled 40 children (age range: 2-16 years) with NS and 40 apparently healthy children (age and sex-matched) as a control group. Anthropometric data, as well as demographic, clinical, and laboratory data, were collected. A dietary intake assessment using a 3-day food intake record was done, and the quadriceps rectus femoris thickness (QRFT) and quadriceps vastus intermedius thickness (QVIT) were assessed using B-mode ultrasound and compared between both groups. RESULTS: Children with NS had lower QRFT and QVIT measurements than control groups (p < 0.001). Inadequacy in protein intake occurred in 62.5% and 27.5% of the NS and control groups, respectively (p = 0.002). The thickness of the rectus and vastus muscles by ultrasound was significantly associated with the percentage of protein intake (p < 0.001). The ROC curve revealed that the best cutoff value of QRFT for the prediction of the patient at risk of malnutrition was ≤ 1.195 with an area under curve of 0.907, with p < 0.001. CONCLUSION: In children with NS, skeletal muscle ultrasound is a simple and easy-to-use bedside technique for the identification of patients at risk of malnutrition. A higher resolution version of the Graphical abstract is available as Supplementary information.

Wide-pulse electrical stimulation of the quadriceps allows greater maximal evocable torque than conventional stimulation.

PURPOSE: The effectiveness of a neuromuscular electrical stimulation (NMES) program has been shown to be proportional to the maximal evocable torque (MET), which is potentially influenced by pulse characteristics such as duration and frequency. The aim of this study was to compare MET between conventional and wide-pulse NMES at two different frequencies. METHODS: MET-expressed as a percentage of maximal voluntary contraction (MVC) torque-and maximal tolerable current intensity were quantified on 71 healthy subjects. The right quadriceps was stimulated with three NMES protocols using different pulse duration/frequency combinations: conventional NMES (0.2 ms/50 Hz; CONV), wide-pulse NMES at 50 Hz (1 ms/50 Hz; WP50) and wide-pulse NMES at 100 Hz (1 ms/100 Hz; WP100). The proportion of subjects reaching the maximal stimulator output (100 mA) before attaining maximal tolerable current intensity was also quantified. RESULTS: The proportion of subjects attaining maximal stimulator output was higher for CONV than WP50 and WP100 (p < 0.001). In subjects who did not attain maximal stimulator output in any protocol, MET was higher for both WP50 and WP100 than for CONV (p < 0.001). Maximal tolerable current intensity was lower for both WP50 and WP100 than for CONV and was also lower for WP100 than for WP50 (p < 0.001). CONCLUSION: When compared to conventional NMES, wide-pulse protocols resulted in greater MET and lower maximal tolerable current intensity. Overall, this may lead to better NMES training/rehabilitation effectiveness and less practical issues associated with maximal stimulator output limitations.

Myotendinous Thermoregulation in National Level Sprinters after a Unilateral Fatigue Acute Bout-A Descriptive Study.

In the last decade there has been a growing interest in infrared thermography in the field of sports medicine in order to elucidate the mechanisms of thermoregulation. The aim of this study was to describe bilateral variations in skin temperature of the anterior thigh and patellar tendon in healthy athletes and to provide a model of baseline tendon and muscle thermoregulation in healthy sprinters following a unilateral isokinetic fatigue protocol. Fifteen healthy national-level sprinters (eleven men and four women), with at least 3 years of athletic training experience of 10-12 h/week and competing in national-level competitions, underwent unilateral isokinetic force testing and electrostimulation in which their body temperature was measured before, during, and after the protocol using an infrared thermographic camera. ANOVA detected a significant difference in the time × side interaction for patellar temperature changes (p ≤ 0.001) and a significant difference in the time/side interaction for quadriceps temperature changes (p ≤ 0.001). The thermal challenge produces homogeneous changes evident in quadriceps areas, but not homogeneous in tendon areas. These data show that metabolic and blood flow changes may depend on the physical and mechanical properties of each tissue. Future research could be conducted to evaluate the predictive value of neuromuscular fatigue in the patellar tendon and quadriceps after exercise in order to optimize post-exercise recovery strategies.

Effect of Functional Electrical Stimulation on Muscle Mass, Fatigue, and Quality of Life in Older Patients With COVID-19: A Randomized Clinical Trial Study.

OBJECTIVE: This study aimed to evaluate the effects of functional electrical stimulation (FES) on muscle strength, fatigue, muscle mass, and quality of life (QoL) in older patients with COVID-19. METHODS: Older patients with COVID-19 were randomly divided into the following 2 groups: real FES (intervention group, n = 20) and sham FES (control group, n = 20). These patients received FES concurrent with the voluntary contraction of muscles for 10 consecutive sessions. Ultrasound imaging, pressure biofeedback, Chalder fatigue scale, and QoL were utilized to measure muscle mass, muscle strength, chronic fatigue, and QoL, respectively. Evaluations were performed at the beginning, immediately, and 1 month after the end of intervention. RESULTS: All variables showed statistically significant improvement immediately and 1 month after the intervention in the real FES group (P < .05). However, the tibialis anterior muscle mass and fatigue significantly improved immediately after the intervention in the sham FES group. However, the tibialis anterior and rectus femoris muscles strength and rectus femoris muscle mass were not significantly changed immediately and 1 month after the intervention (P > .05). There were significant differences in muscle mass, physical fatigue, muscle strength, and QoL between groups with more efficacy of real FES (P < .05). CONCLUSION: For this sample of patients, FES improved fatigue, muscle strength, muscle mass, and QoL in older adults with COVID-19.

Clinical applications of the chimeric anterolateral thigh (ALT) flap in head and neck reconstruction.

BACKGROUND: Surgical site infection (SSI) is a common complication following head and neck surgery. Dead space at the excision site can increase the risk of infection, abscess formation, and mortality. Herein, we evaluated the performance of the chimeric anterolateral thigh (ALT) flap in addressing these concerns. METHODS: Patients who underwent oncologic head and neck reconstruction between October 2016 and November 2021 were divided in two groups: a normal ALT flap and a chimeric dead space filling (DSF) ALT-vastus lateralis flap group. We evaluated the postoperative outcomes. RESULTS: Twenty-five patients treated with normal ALT flaps (34.7%) and 47 with DSF ALT flap group (65.2%) were included. Only one ALT per case was necessary. Most of the cases involved tongue (31.9%) and lower gingival reconstruction (27.8%). The time to harvest the DSF ALT flap was 134.3 min when compared to the normal ALT flap (116.2 min, p < .001). Vascular occlusion, flap loss, partial necrosis, and fat necrosis were not observed among the different groups. CONCLUSION: The DSF process can be used as a preventive measure for SSI or vessel exposure due to radiation-induced skin damage. This flap allows same-site reconstruction if the primary tumor recurs by using the pedicle of the chimeric flap for reattachment of another free flap.

The Effect Of Gender On Vastus Medialis Oblique/Vastus Lateralis Activation Ratio During Weight And Non-Weight Bearing Activities In Recreationally Subjects.

Objectives: To investigate the effect of gender on the activation ratio of vastus medialis oblique to vastus lateralis during straight leg raising and stepdown activities. Method: The cross-sectionalstudy was conducted at the College of Medical Rehabilitation Sciences, Taibah University, Medina, Kingdom of Saudi Arabia, from September 2021 to March 2022, and comprised recreationally active subjects without knee pathology who were distributed in 2 gender-based groups. All the participants were subjected to straight leg raising and stepdown activitiesthrice and the average value of each activity was noted. The vastus medialis oblique and vastus lateralis electromyographic activity of the dominant limb was recorded using surface electromyography during the activities. The normalised value of the activation ratio of vastus medialis oblique to vastus lateralis levels was calculated. Data was analysed using SPSS 25. RESULTS: Of the 60 subjects, there were 30(50%) males with mean age 30.00±5.91 years, mean height 167±5.63cm, mean body weight 66.76±6.14kg, and mean body mass index 23.97±3.02kg/m2 . There were 30(50%) females with mean age 29.03±5.34 years, mean height 186±6.20cm, mean body weight 68.5±5.6 kg and mean body mass index 23.76±3.22 kg/m2 . There was no significant difference in the normalized electromyography activities of the vastus medialis oblique and vastuslateralis muscles between males and females(p>0.05). Also, no significant difference was found in the activation ratio between the genders (p>0.05). CONCLUSIONS: There were no gender-based differencesin the activation ratio of vastus medialis oblique to vastuslateralis during weight-bearing and non-weight-bearing activities.

Downhill running affects the late but not the early phase of the rate of force development.

PURPOSE: This study aimed to evaluate the acute changes in the knee extensors maximum voluntary isometric contraction force (MVIC), rate of force development (RFD), and rate of EMG rise (RER) following a bout of downhill running. METHODS: MVIC and RFD at 0-50, 50-100, 100-200, and 0-200 ms were determined in thirteen men (22 ± 2 yr) before and after 30 min of downhill running (speed: 10 km h-1; slope: - 20%). Vastus lateralis maximum EMG (EMGmax) and RER at 0-30, 0-50, and 0-75 ms were also recorded. RESULTS: MVIC, RFD0-200, and EMGmax decreased by ~ 25% [Cohen's d = - 1.09 (95% confidence interval: - 1.88/- 0.24)], ~ 15% [d = - 0.50 (- 1.26/0.30)], and ~ 22% [d = - 0.37 (- 1.13/0.42)] (all P < 0.05), respectively. RFD100-200 was also reduced [- 25%; d = - 0.70 (- 1.47/0.11); P < 0.001]. No change was observed at 0-50 ms and 50-100 ms (P ≥ 0.05). RER values were similar at each time interval (all P > 0.05). CONCLUSION: Downhill running impairs the muscle capacity to produce maximum force and the overall ability to rapidly develop force. No change was observed for the early phase of the RFD and the absolute RER, suggesting no alterations in the neural mechanisms underlying RFD. RFD100-200 reduction suggests that impairments in the rapid force-generating capacity are located within the skeletal muscle, likely due to a reduction in muscle-tendon stiffness and/or impairments in the muscle contractile apparatus. These findings may help explain evidence of neuromuscular alterations in trail runners and following prolonged duration races wherein cumulative eccentric loading is high.

Do Patients Really Have Pain with Quadriceps Fat Pad Edema?

OBJECTIVE: To determine the appropriate MRI criteria for the radiological diagnosis of significant quadriceps fat pad edema, to investigate the relationship between these criteria and anterior knee pain, and to evaluate possible structural and positional factors in the etiology. MATERIAL AND METHODS: In this retrospective case-control study, individuals with and without quadriceps fat pad edema in the knee MRIs taken between May 2016 and December 2018 were determined as the case and control groups, respectively, in a ratio of 1:1. The MRI criteria for significant quadriceps fat pad edema were set as 10 mm and above the anterior-posterior diameter of the quadriceps fat pad, posterior convexity, and an increased signal in the fat-suppressed proton density sequence. The groups were compared for anterior knee pain, pain characteristics, working positions (sitting and standing), and MRI findings of structural factors. P < 0.05 was considered statistically significant. RESULTS: A total of 108 individuals were evaluated. Anterior knee pain was more common in the case group (49/54, p < 0.001) and was highly correlated with signs of quadriceps fat pad edema (R = -0,657). Frequent pain at night (18/54, p = 0.013), increased pain when walking upstairs (40/54, p = 0.003), knees are flexed (43/54, p < 0.001), and decreased pain when knees are extended (42/54, p < 0.001) were significantly high in the case group. No significant differences were observed in working position and structural factors. CONCLUSION: Quadriceps fat pad edema is significantly associated with anterior knee pain and certain specific pain characteristics.

Knee extensor muscle weakness is a risk factor for the development of knee osteoarthritis: an updated systematic review and meta-analysis including 46 819 men and women.

OBJECTIVE: To update a systematic review on the association between knee extensor muscle weakness and the risk of incident knee osteoarthritis in women and men. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Systematic searches in PubMed, EMBASE, SPORTDiscus, CINAHL, AMED and CENTRAL in May 2021. ELIGIBLE CRITERIA FOR SELECTING STUDIES: Longitudinal studies with at least 2 years follow-up including baseline measure of knee extensor muscle strength, and follow-up measure of symptomatic or radiographic knee osteoarthritis. Studies including participants with known knee osteoarthritis at baseline were excluded. Risk of bias assessment was conducted using six criteria for study validity and bias. Grading of Recommendations Assessments, Development and Evaluation assessed overall quality of evidence. Meta-analysis estimated the OR for the association between knee extensor muscle weakness and incident knee osteoarthritis. RESULTS: We included 11 studies with 46 819 participants. Low quality evidence indicated that knee extensor muscle weakness increased the odds of symptomatic knee osteoarthritis in women (OR 1.85, 95% CI 1.29 to 2.64) and in adult men (OR 1.43, 95% CI 1.14 to 1.78), and for radiographic knee osteoarthritis in women: OR 1.43 (95% CI 1.19 to 1.71) and in men: OR 1.39 (95% CI 1.07 to 1.82). No associations were identified for knee injured populations except for radiographic osteoarthritis in men. DISCUSSION: There is low quality evidence that knee extensor muscle weakness is associated with incident symptomatic and radiographic knee osteoarthritis in women and men. Optimising knee extensor muscle strength may help to prevent knee osteoarthritis. PROSPERO REGISTRATION NUMBER: CRD42020214976.

Preoperative muscle thickness influences muscle activation after arthroscopic knee surgery.

PURPOSE: The aim of this study was to compare the correlation between preoperative quadriceps femoris muscle thickness and postoperative neuromuscular activation and quadriceps femoris strength in patients with and without patellofemoral pain after arthroscopic partial meniscectomy. METHODS: A series of 120 patients were prospectively analysed in a longitudinal cohort study of patients scheduled for arthroscopic partial meniscectomy. The patellofemoral pain group included patients who developed anterior knee pain after surgery while the control group included those who had not done so. Patients with preoperative patellofemoral pain, previous knee surgeries as well as those on whom additional surgical procedures had been performed were excluded. Of the 120 initially included in the study, 90 patients were analysed after the exclusions. RESULTS: There is a direct correlation between preoperative quadriceps femoris muscle thickness and the neuromuscular activity values and the strength of the muscle at 6 weeks after surgery. These results were seen exclusively in the group of patients who do not develop patellofemoral pain (0.543, p = 0.008). The group of patients who developed anterior knee pain in the postoperative period did not show this correlation (n.s.). CONCLUSION: In patients without patellofemoral pain after meniscectomy, the greater the preoperative thickness of the quadriceps femoris, the more postoperative neuromuscular activation and strength they had. This correlation did not occur in those patients who develop patellofemoral pain after meniscal surgery. LEVEL OF EVIDENCE: II.

Should proximal ruptures of the anterior rectus femoris muscle be treated surgically?

PURPOSE: No therapeutic consensus has been established about proximal ruptures of the rectus femoris muscle. The objective of this literature review is to determine a therapeutic course of action. METHODS: We conducted a literature review on the PubMed database using the following keywords (in French and English, respectively): "quadriceps/quadriceps", "droit antérieur/rectus femoris", "proximal/proximal", "chirurgie/surgical", "avulsion/avulsion". We collected 266 articles, 36 of them were selected, which were related to our topic: proximal rupture of the anterior rectus femoris. Patients with a proximal rupture of the rectus femoris, minor or major patient of traumatic origin were included in this study. Patients injured at another lesion level, or non-traumatic lesions of the proximal rectus femoris (tendinitis without ruptures, tumor or others) were excluded. For each patient, the indications, the type of treatment and the functional result were analyzed, with the time to recovery and the level of recovery from sports and professional activities (same sport/profession or not, same level or not) as the main criterion of judgment. Fisher exact test was used for statistical comparison. RESULTS: The aims of conservative treatment are to be pain free for the patient, to fight hematoma and to rehabilitate the injury as quickly as possible. The surgical techniques are varied, with most consisting of either a reinsertion of the musculo-tendon stump or a resection of the scar tissue with myo-tendino-aponeurotic suture in place. The functional results are good for the majority of the treatments proposed, but the conservative treatment has a shorter recovery time (3 months vs. 4 months for the best surgical results). Highly displaced bone avulsion is the only indication for first-line surgical treatment. CONSLUSION: The main disadvantage of conservative treatment is the risk of residual pain beyond 3 months (10%), justifying an MRI to guide secondary surgical treatment. We propose a treatment plan for proximal rupture of the proximal rectus femoris rupture.

The Nonintuitive Contributions of Individual Quadriceps Muscles to Patellar Tracking.

The purpose of this study was to quantify the contribution of the individual quadriceps muscles to patellar tracking. The individual and/or combined quadriceps muscles were activated in rabbits (n = 6) during computer-controlled flexion/extension of the knee. Three-dimensional patellar tracking was measured for the vastus lateralis, vastus medialis, and rectus femoris when activated alone and when activated simultaneously at different frequencies, producing a range of knee extensor torques. Patellar tracking changed substantially as a function of knee extensor torque and differed between muscles. Specifically, when all quadriceps muscles were activated simultaneously, the patella shifted more medially and proximally and rotated and tilted more medially compared with when vastus lateralis and rectus femoris were activated alone (P < .05), whereas vastus medialis activation alone produced a similar tracking pattern to that observed when all quadriceps muscles were activated simultaneously. Furthermore, patellar tracking for a given muscle condition shifted more medially and proximally and rotated and tilted more medially with increasing knee extensor torques across the entire range of knee joint angles. The authors conclude that patellar tracking depends crucially on knee extensor force/torque and that vastus medialis affects patellar tracking in a distinctly different way than vastus lateralis and rectus femoris, which produce similar tracking patterns.