Static Knee Research Articles

Comparison of Static, Dynamic Balance, Knee Joint Position Among Healthy Women and Those Infected with COVID-19

Background and Aims: The Coronavirus disease 2019 (COVID-19) pandemic has created widespread and long-lasting impacts on human health. Infection induces harm and damage to various systems, including the respiratory, digestive, kidney, and central nervous systems. Hence, considering its effects on the central nervous system (CNS) and nervous disorders and the fact that the CNS can impact balance and “position sense”, the objective of this study was to compare static balance, dynamic balance, and knee joint position sense among women (with COVID-19 and healthy subjects). Methods: In this study, 15 women infected with COVID-19 (age: 47.73±3.44 years, height: 162.53±4.17 cm, mass: 70.33±4.67 kg, and body mass index (BMI): 26.63±1.62 kg/m2) and 15 healthy women (age:47.53±3.27 years, height: 161.13±4.56 cm, and mass: 67.66±4.25 kg, and BMI: 26.11±2.10 kg/m2) were analyzed. Sharpendromberg and time up and go tests were utilized to respectively evaluate static and dynamic balance as well as knee joint position sense. The data were recorded by angular reconstruction and via a digital camera. Balance and sense of status tests were performed for both groups, and ultimately, the results were evaluated utilizing an independent t-test. Results: The findings revealed a significant difference between static and dynamic balance among the two groups of women (with COVID-19 & healthy) (P<0.05). Moreover, there was a significant difference between knee joint position sense (P<0.05), where the COVID group had 2.64 degrees more reconstruction error than the healthy group. Conclusion: The static, dynamic balance, and knee joint position sense of the COVID group decreased, which can lead to an increase in the contingency of dropping/falling among these individuals.

Relationship between radiographic measurements and knee adduction moment using 3D gait analysis.

Radiographic factors estimate the state of the static knee joint, and it is questionable how well these parameters reflect the dynamic knee condition. The external knee adduction moment (KAM) during gait is known to be a kinetic variable contributing to osteoarthritis progression. This study aims to investigate the effects of static radiographic parameters on the dynamic KAM during gait. Overall, 123 patients (mean age, 65.7 years; standard deviation, 8.1 years; 34 men and 89 women) were included. Seven radiographic parameters including the mechanical tibiofemoral angle (mTFA), Kellgren-Lawrence grade, and ankle joint line orientation (AJLO) were measured on radiographs, and the maximum KAM and KAM-time integral in the stance phase were obtained using three-dimensional gait analysis. The correlation and multiple regression analyses were performed for identifying significant radiographic measurements associated with the KAM. Most of the radiographic measurements correlated with the maximum KAM and KAM-time integral. As a result of multiple regression analysis, the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as significant factors associated with the KAM-time integral (R2 = 0.450); the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as a significant factor associated with the maximum KAM (R2 = 0.352) in multiple regression analysis. The discriminant validity of KAM was highest at varus 5.7 degree of the mTFA and 7.5 degree of the AJLO. The mTFA and AJLO were significantly associated with the KAM. However, to be used as a surgical indication for corrective osteotomy, a longitudinal study is needed to validate whether the mTFA and AJLO values directly cause osteoarthritis progression as we have suggested. III.

Effect of static knee joint flexion on vastus medialis obliquus fiber angle in patellofemoral pain syndrome: An ultrasonographic study.

In patients with patellofemoral pain syndrome, the vastus medialis obliquus muscle fiber angle measured by ultrasound at knee extension was found to be different from that in healthy individuals. An important feature of patellofemoral pain syndrome is the increase in pain severity during activities that require knee flexion. To investigate whether there was an ultrasonographic change in the vastus medialis obliquus fiber angle by flexing the knee joint in patients with patellofemoral pain syndrome compared to healthy pain-free individuals. A cross-sectional clinical study. An outpatient clinic of a tertiary care hospital. Forty-seven patients with patellofemoral pain syndrome (median age of 40 years) and 43 healthy volunteers (median age of 39 years) were included in the study. No intervention. Vastus medialis obliquus fiber angle measured by ultrasonography at three different positions of knee joint including extension, 30° of flexion, and 45° of flexion. There was no significant change in the vastus medialis obliquus fiber angle with knee flexion in both groups (p > .05 for each group). However, the median vastus medialis obliquus fiber angle values in the group with patellofemoral pain syndrome were significantly lower at all knee joint angles than those in the comparison group (p < .05 at all knee joint angles). Although the vastus medialis obliquus fiber angle does not change with static knee flexion, the lower angle of the vastus medialis obliquus fiber in those with patellofemoral pain syndrome implicitly suggests that vastus medialis obliquus dysfunction may exist.

The knee position at tourniquet inflation does not affect the gap balancing during total knee arthroplasty.

The relationship between gap balancing and clinical outcome of total knee arthroplasty (TKA) has been researched. Tourniquet is widely used by most surgeons; however, there are little quantitative data about the gap depending on the tourniquet usage. We aimed to investigate whether the knee position at tourniquet inflation affected the gap measurement intra-operatively. TKA was performed for 104 knees and the tourniquet was inflated with the knee at full flexion and extension. The gap was measured in each static knee flexion status (0°, 30°, 45°, 60°, 90°, 120°, and in full flexion) using a tensor. We measured the gap twice; under the tourniquet inflation and release. The gap difference at each static knee flexion status was calculated by subtracting the gap under release from that under inflation. When the tourniquet was inflated with the knee at full flexion, the mean gap differences were < 1mm and < 1° in each static knee flexion status. When the tourniquet was inflated with the knee at full extension, the mean gap differences were < 1mm and < 1°, respectively. All values of the gap difference were minimum, and were not affected by the tourniquet, whether the knee position at the tourniquet inflation was flexed or extended. We postulated that the knee position at tourniquet inflation would affect the gap, which was refuted by our results. This shows that we can measure the gap without considering the knee position at tourniquet inflation.

Blood pressure responses to static and dynamic knee extensor exercise between sexes: Role of absolute contraction intensity

Males have larger blood pressure (BP) responses to relative intensity static handgrip exercise compared to females. Controlling for maximal voluntary contraction (MVC) absolute strength abolishes these differences. Whether similar observations exist during large muscle mass exercise or dynamic contractions remain unknown. BP, heart rate, muscle oxygenation (near-infrared spectroscopy), and rectus femoris electromyography (EMG) were recorded in 28 males and 17 females during 10% and 30% MVC static (120s) and isokinetic dynamic (180s; 1:2 work-to-rest ratio; angular velocity: 60º/s) knee extensor exercise. At baseline and during exercise, continuous BP and heart rate were measured using finger photoplethysmography and single-lead electrocardiography, respectively. MVC, as well as all submaximal exercise testing, was measured and performed on a dynamometer at 80⁰ of knee flexion, and voluntary activation was assessed using the interpolated twitch technique, with ≥90% voluntary activation of the knee extensors set as the acceptable activation threshold. Static and dynamic exercises were completed on separate visits, in a randomized order. The change from baseline of each variable was calculated for every 30 s during each submaximal test. Sex differences were then examined with and without statistical adjustment of MVC using analyses of covariance (ANCOVA). The males were taller and heavier than the females and had higher resting systolic BP (all P<0.05), while BMI, resting diastolic and mean arterial BP, and heart rate were similar between sexes (all P>0.05). Knee extensor MVC was higher in males than females (165 ± 40 vs. 94 ± 22 Nm, P<0.0001). Males had larger systolic BP responses (interaction, P<0.001) and muscle deoxygenation (interaction, P<0.01) than females during 10% static exercise, with no difference in EMG (interaction, P=0.73). Peak systolic BP was correlated to MVC (r=0.53, P=0.0002), and adjustment for MVC abolished sex differences in systolic BP (interaction, P=0.5). BP, heart rate, muscle oxygenation/deoxygenation, and EMG responses did not differ between sexes during 30% static exercise (interaction, All P>0.2), including following adjustment for MVC (All P>0.1). Males had larger systolic BP responses during dynamic exercise at 10% and 30% (interaction, Both P=0.01), which were abolished after adjustment for MVC (interaction, Both P>0.08). Systolic BP responses at 180s were correlated with MVC and stroke volume responses during 10% (r=0.31, P=0.04; r=0.61, P<0.0001, respectively) and 30% (r=0.4, P=0.007; r=0.59, P<0.0001, respectively). In conclusion, MVC can influence systolic BP responses to 10% but not 30% MVC static, as well as 10% and 30% MVC dynamic knee extensor exercise. MVC should be considered when comparing BP responses between males and females. Finally, the mechanisms mediating the larger pressor responses in stronger individuals across different exercise modalities warrant further investigation.

Static balance and proprioception evaluation in deaf national basketball players

Background: ‪Because of the proximity of anatomical structures involved in auditory and vestibular functions, complications concerning the inner ear may lead to problems involving both systems. This study investigated whether static balance and knee proprioception in deaf basketball players are different from those in individuals with normal hearing. Material and methods: ‪12 deaf national basketball players and 13 individuals with normal hearing were included. Static balance was evaluated using the Biodex-BioSway Balance System. Knee proprioception was assessed using a Dualer IQ Digital Inclinometer with the active angle repetition test. Results: ‪The dominant-side mediolateral stability index and non-dominant-side overall, anteroposterior, and mediolateral stability index scores of deaf basketball players in the postural stability test were different compared with those of the individuals with normal hearing (p&lt;0.05). There was no statistically significant difference between the two groups in terms of knee proprioception (p&gt;0.05). Conclusions: ‪Although there was no difference in knee proprioception in deaf basketball players, it is noteworthy that their postural stability was more impaired compared with that in individuals with normal hearing. Despite regular exercise, deaf basketball players had poorer balance than individuals with normal hearing. Therefore, balance and vestibular exercises should be added to the training programs of these athletes.

Blood Pressure Responses to Static and Dynamic Knee Extensor Exercise between Sexes: Role of Absolute Contraction Intensity.

Males have larger blood pressure (BP) responses to relative-intensity static handgrip exercise compared with females. Controlling for absolute load (maximal voluntary contraction (MVC)) abolishes these differences. Whether similar observations exist during large muscle mass exercise or dynamic contractions, and the mechanisms involved, remains unknown. BP, heart rate, muscle oxygenation (near-infrared spectroscopy), and rectus femoris EMG were recorded in 28 males and 17 females during 10% and 30% MVC static (120 s) and isokinetic dynamic (180 s; 1:2 work-to-rest ratio; angular velocity, 60°·s-1) knee extensor exercise. Static and dynamic exercises were completed on separate visits, in a randomized order. Sex differences were examined with and without statistical adjustment of MVC (ANCOVA). Males had larger systolic BP responses (interaction, P < 0.0001) and muscle deoxygenation (interaction, P < 0.01) than did females during 10% static exercise, with no difference in EMG (interaction, P = 0.67). Peak systolic BP was correlated with MVC (r = 0.55, P = 0. 0001), and adjustment for MVC abolished sex differences in systolic BP (interaction, P = 0.3). BP, heart rate, muscle oxygenation/deoxygenation, and EMG responses were similar between sexes during 30% static exercise (interaction; all, P > 0.2), including following adjustment for MVC (all, P > 0.1). Males had larger systolic BP responses during dynamic exercise at 10% and 30% (interaction; both, P = 0.01), which were abolished after adjustment for MVC (interaction; both, P > 0.08). Systolic BP responses were correlated with absolute MVC and stroke volume responses during 10% (r = 0.31, P = 0.04; r = 0.61, P < 0.0001, respectively) and 30% (r = 0.48, P = 0.001; r = 0.59, P < 0.0001, respectively). Absolute contraction intensity can influence systolic BP responses to 10% but not 30% MVC static, as well as 10% and 30% MVC dynamic knee extensor exercise, and should be considered in cross-sectional comparisons of exercise BP.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% (P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces (P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced (P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

Hand-Held Dynamometry in the Inpatient Care Setting After Total Knee Arthroplasty: Reliability of Static Knee Strength Measurements.

The aim of the study was to determine intrarater and interrater reliabilities for static strength assessment of knee flexors and knee extensors in patients with total knee arthroplasty, during the acute postoperative rehabilitation. Forty-five total knee arthroplasty patients were included in the study. Two physical therapists performed strength assessments by using hand-held dynamometry. Patients performed three trials and a 30-sec rest was provided between each trial. After this, a 5-min rest was provided, and then, a second investigator performed the same procedure for interrater reliability. Assessments for intrarater reliability were performed 1 hr later. The intrarater reliability of knee extensors and knee flexors strength measurements were 0.96 and 0.94, respectively. The standard error of measurement and minimal detectable change 95% confidence level were 6.17 and 17.01 Nm for knee extensors and were 8.89 and 24.51 Nm for knee flexors, respectively. The interrater reliability of knee flexors and knee extensors strength measurement was 0.96 for both. The standard error of measurement and minimal detectable change values at 95% confidence level were 6.00 and 16.54 Nm for knee extensors and were 6.32 and 17.42 Nm for knee flexors, respectively. Hand-held dynamometry is a reliable method to assess static knee strength. Hand-held dynamometry assessment can be implemented during acute postoperative rehabilitation. Our results may assist the clinicians in determining an accurate postoperative rehabilitation program after total knee arthroplasty surgery.

Correlation of static knee angle in kinematic and radiographic in medial knee osteoarthritis

Abstract Introduction The hip-knee-ankle (HKA) angle measured on a full-length weight bearing X-ray made in standing position is considered the gold standard to measure the knee static alignment. However, this method requires special equipment, involves significant radiation exposure and generates extra costs. The 3D motion capture can assess knee angles in a reliable and accurate way. Objectives This study aimed to analyse the correlation between the HKA angle achieved in full-length X-ray and the in static knee kinematic analysis in patients with medial knee osteoarthritis (OA). Methodology A descriptive study was design. Anterior-posterior full-limb radiographs were obtained using standard procedures in the same hospital. The HKA angle was measure by an experimental orthopaedic doctor. The kinematics were obtained using Visual3D software after 3D motion capture in two static positions: static comfortable position (Static-1) and a static standard position (Static-2). Kinematic data were filtered (6 Hz) and expressed in degrees (°). The knee joint was created by the distance between the distal end of the thigh and the proximal end of the shank. The angles lower than 180° were considered as varus alignment and those higher than 180° valgus alignment. Results This study includes 36 patients (22 females; mean age 61,6 ± 8,4; weight 75,8 ± 12,7 kg, and height 161 ± 9,2 cm) with diagnosed medial knee OA Kellgren/Lawrence grade 2 (16 patients) or 3. The patients presented a mean of HKA of 176,2° ± 3,2 in X-ray; 182,1° ± 6,0 in Static-1 and 180,0° ± 5,6 in Static-2. A significant correlation was found between HKA angle and Static-1 (r = 0,525; p = 0,001) and between HKA angle and Static-2 (r = 0,556; p = 0,000). Conclusion A moderate but significant correlation was found between X-ray and two measure of 3D motion capture in frontal knee angle. Clinically, 3D analysis may help health care professionals in a more practical way to identify the joint angles.

Non-invasive computer navigation can quantify the pivot shift maneuver with good to excellent reliability in healthy volunteers

PurposeThe aim of this study was to determine the inter- and intra-observer reliability of knee laxity assessment using a non-invasive navigation system in a population of healthy young athletes. It was hypothesized that knee laxity parameters recorded using non-invasive computer navigation would demonstrate good inter- and intra-observer reliability.MethodsHealthy volunteers aged between 18 to 30 years were recruited to the study. Static and dynamic knee laxity parameters including anterior tibial translation and tibial rotation during the pivot shift test were recorded on awake patients using non-invasive computer navigation by two independent observers: at the first visit each athlete was evaluated by the consultant and resident surgeons independently; 6 weeks after the first visit all the participants were re-tested only by the resident surgeon. Inter- and intra-observer reliability was calculated and then interpreted according to Cicchetti’s criteria.ResultsOne hundred healthy volunteers were recruited to the study, of these 38 were women (38%), and the average age was 25.5 ± 2.4 years. According to Cicchetti’s criteria the intra- and inter-observer reliability for static measurements were fair for anterior tibial translation (0.572 and 0.529, respectively) and excellent for total passive tibial rotation (0.859 and 0.883, respectively). For the dynamic measurements of translation and rotation during the pivot shift maneuver both measurements demonstrated good to excellent reliability with intra and inter observer reliability ranging from 0.684 to 0.936.ConclusionNon-invasive navigation for the assessment of knee laxity is associated with fair to excellent inter- and intra-observer reliability in a population of healthy volunteers.

Role of absolute muscle strength in determining the blood pressure response to static and dynamic knee extension

Relative contraction intensity is considered the primary factor determining the hemodynamic response to exercise, though premenopausal women still commonly present with lower blood pressure (BP) and heart rate responses. Our group has shown that within‐ and between‐sex differences in BP responses during static handgrip are abolished when controlling for maximal voluntary effort (MVE). Whether these findings apply to static contractions in the lower limb, dynamic contractions, or are affected by differences in contraction intensity remain untested. 27 young healthy men and women (23±3 years [mean ±SD]; 10 women) performed static and dynamic single leg knee extensor exercise on 2 separate visits, with one modality being tested during a single visit. Both contraction types were performed at 3 separate intensities, 10% MVC, 30% MVC, and 25 nM as an absolute intensity, with 20 minutes of recovery between bouts. All static contractions were held for 2 minute bouts, whereas the dynamic tasks were performed for 3 minutes. Dynamic contractions were performed at a 1:2 second work‐to‐rest ratio at a velocity of 60□/second. The intensities were tested in order from lowest to highest. At baseline and during exercise, continuous BP and heart rate were measured using finger photoplethysmography and single‐lead electrocardiography, respectively. MVC was measured from the left knee extensors on a dynamometer (HUMAC‐norm) at 80□ of knee flexion, and voluntary activation was assessed using the interpolated twitch technique, with ≥90% voluntary activation of the knee extensors set as the acceptable activation threshold. To compare those with HIGH and LOW muscle strength, we split males and females separately by the median MVC. BP and heart rate responses were assessed as the difference from baseline to the last minute of exercise. The groups were matched for baseline characteristics aside from the HIGH group having a higher body mass (78±13 vs. 67±9 kg, p=0.02). By design, knee extensor MVC was different between groups (169±57 vs. 114±38 Nm, p=0.009). During the second minute of the 10% static contractions, diastolic BP responses were larger in HIGH compared to LOW participants (Δ10±4 vs. 6±3 mmHg, p=0.01). The changes in systolic BP (Δ16±9 vs. 10±7 mmHg, p=0.06) and heart rate (Δ11±8 vs 6±4 beats/minute, p=0.07) were also trending towards being larger in HIGH participants. In contrast, the changes in BP and heart rate were not statistically different during the 30% static MVC contraction or the absolute intensity contraction between groups (all p=0.17). During 10% dynamic contractions, systolic BP responses were trending towards being larger in HIGH participants (Δ8±6 vs. 4±4 mmHg, p=0.06), while heart rate responses were greater during 30% dynamic contractions in HIGH participants (Δ14±5 vs. 9±6 beats/minute, p=0.02). In conclusion, our data suggest that absolute torque affects BP and heart rate responses during lower limb static and dynamic knee extension exercise. The mechanisms responsible for how absolute torque influences BP and heart rate warrants future investigation.Support or Funding InformationNatural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant; Canada Foundation for Innovation

Effects of Combining Running and Practical Duration Stretching on Proprioceptive Skills of National Sprinters.

Romero-Franco, N, Párraga-Montilla, JA, Molina-Flores, EM, and Jiménez-Reyes, P. Effects of combining running and practical duration stretching on proprioceptive skills of national sprinters. J Strength Cond Res 34(4): 1158-1165, 2020-Practical duration stretching after aerobic activities is a recommended component of the first part of warm-up because of its effects on performance. However, its effects on proprioceptive skills are unknown. This study aimed to analyze the effects of running and practical duration static stretching (SS) and dynamic stretching (DS) on postural balance and the joint position sense (JPS) of national sprinters. Thirty-two national sprinters were randomly classified into a SS group (n = 11), DS group (n = 11), or control group (n = 10). Static stretching performed 5 minutes of running and short-duration (20 seconds) static stretches; DS performed 5 minutes of running and short-duration dynamic (20 seconds) stretches; and the control group performed 5 minutes of running. Before and after the intervention, unipedal static postural balance and knee JPS were evaluated. Static stretching exhibited a more centralized center of pressure in the medial-lateral plane for unipedal static postural balance in right-leg support after stretching (p = 0.005, d = 1.24), whereas DS showed values further from the center after stretching for the same unipedal support compared with baseline (p = 0.042, d = 0.49), and the control group remained stable (p > 0.05). Joint position sense did not show significant differences in any group (p > 0.05). In conclusion, combining running and practical duration SS may be beneficial for right-leg postural stabilization, whereas DS may be partly and slightly deleterious. Both SS and DS combined with running and running alone have neutral effects on knee JPS. Sports professionals should consider running and practical duration SS as part of the warm-up of sprinters to partly improve unipedal static postural balance.

The Impact of Various Physiotherapy Programs on the Balance, Knee Proprioception, and Flexors/Extensors Strength after Anteriorcruciate Ligament Reconstruction

The decrease in knee flexors and extensors strength and poor balance are related to the impairment of the knee proprioception after anterior cruciate ligament reconstruction [1, 2]. Therefore, it is important to assess the impact of various physiotherapy programs on static balance, knee proprioception, and thigh muscle strength, and at the same time pursue the qualitative rehabilitation as well as look for the possibilities of assessment of knee proprioception using the isokinetic dynamometer. Twenty volunteers (aged 26–36 years) participated in the study four–five weeks after anterior cruciate ligament reconstruction. The participants were divided into two groups: trial group (n = 10; two women, eight men) and control group (n = 10; two women, eight men). Complementary neuromuscular training and the ordinary physiotherapy program were applied to the trial group for three weeks; the control group received only the ordinary physiotherapy program. Static balance (using Balance error scoring system), knee proprioception (using the isokinetic dynamometer), and thigh muscle strength (using Lovett scale) were determined before and after the three-week intervention period. Participants had to indicate the position of the tested leg, i. e. whether the knee was flexed at 30 or 60 degrees. We established the difference between the indicated and real position of the leg in degrees. The mentioned difference indicated the state of knee proprioception. The outcomes of static balance significantly improved after three weeks of physiotherapy in both groups: trial group — from 12.3 ± 3.4 to 2.1 ± 0.8 errors (p &lt; 0.01), control group – from 12.2 ± 1.6 to 4.2 ± 0.9 errors (p &lt; 0.01). Also, the trial and control groups demonstrated improved condition of knee proprioception at both angular velocities of 15 degrees/s and 30 degrees/s. There were no differences between standard means of knee flexors strength before the intervention. The outcomes of knee flexors strength of the trial group were significantly higher as compared to the outcomes demonstrated by the control group (p &lt; 0.05). There were no significant differences in knee extensors strength between both groups. Thus, values of static balance, knee proprioception, and flexors/extensors strength change more rapidly when frequent and longer neuromuscular training is applied. The ordinary physiotherapy program has a positive but less effect on the above mentioned variables.Keywords: anterior cruciate ligament, static balance, proprioception, muscle strength, neuromuscular training.

The impact of body-mass index on the frontal knee alignment estimation using three-dimensional reconstruction based on movement analysis

BackgroundWe evaluated the influence of the body-mass index (BMI) on the estimation of the static frontal knee alignment (FKA) using three-dimensional (3D) reconstruction method based on movement analysis. MethodsTwo-hundred nineteen knees (120 individuals with end-stage osteoarthritis) were analyzed. The validity of the 3D method was evaluated under comparison with a reference method based on weight bearing full-leg length radiography. Extensive statistical analyses (Pearson's correlation, one-way ANOVA, linear regression, boxplot diagram) over four groups of BMI (normal, overweight, obese class I and obese classes II and III) were performed. ResultsFor BMI below 25 kg/m2, the validity of the 3D method was confirmed. For BMI over 25 kg/m2, there was an increasing error of the 3D method, especially for the obese groups affected with a large varus alignment. ConclusionsIn a biomechanical context of movement analysis, the results of the study suggest that the 3D method may represent a satisfying alternative to the full-leg radiograph method with limitations regarding to BMI over 25 kg/m2.

In vivo static and dynamic lengthening measurements of the posterior cruciate ligament at high knee flexion angles.

Rehabilitation is an important aspect of both non-operative and operative treatments of knee ligament tear. Posterior cruciate ligament (PCL) non-operative treatment consists of a step-by-step rehabilitation protocol and is well described. It goes from rest (phase I) to strengthening exercises (phase IV). More specific and high-intensity exercises such as cutting, sidestepping or jumps are, however, not described in detail, as no in vivo data exist to tell how these exercises constrain the ligaments and whether they have the same effect on all of them, in particular regarding lengthening. The goal of this study was to measure the ligament lengthening in static knee flexion based on 3D reconstructions from magnetic resonance imaging (MRI) and from motion capture and ligament simulation during dynamic exercises. The knee of nine volunteers was first imaged in a closed-bore MRI scanner at various static knee flexion angles (up to 110°), and the corresponding lengthening of the PCL and the other major knee ligaments was measured. Then, the volunteers underwent motion capture of the knee where dynamic exercises (sitting, jumping, sidestepping, etc.) were recorded. For each exercise, knee ligament elongation was simulated and evaluated. According to the MRI scans, maximal lengthening occurred at 110° of flexion in the anterior cruciate ligament and 90° of flexion in the PCL. Daily living movements such as sitting were predicted to elongate the cruciate ligaments, whereas they shortened the collateral ligaments. More active movements such as jumping put the most constrain to cruciate ligaments. This study provides interesting insights into a tailored postoperative regimen. In particular, knowing the knee ligament lengthening during dynamic exercises can help better define the last stages of the rehabilitation protocol, and hence provide a safe return to play.

Correlation between static limb alignment and peak knee adduction angle during gait is affected by subject pain in medial knee osteoarthritis

BackgroundAlthough increases in knee adduction moment (KAM) and angle (KAA) during gait are considered key pathologies that produce mechanical overload in the medial compartment of knee osteoarthritis (OA), it is unclear how these pathologies are related to subjective pain. The purpose of this study was to examine how subjective pain is related to such pathologies. MethodsGait analysis was performed in 31 participants with medial knee OA. The knees were classified into three groups based on Kellgren–Lawrence (KL) grade: early (0 and 1), moderate (2), and severe (3 and 4). Subjective pain was evaluated by the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index pain score. The knees were classified into low- and high-pain groups based on the pain score. ResultsThe WOMAC pain score did not correlate with either peak KAM or peak KAA. Although a positive correlation between static limb alignment and peak KAA was observed in the low-pain group, it was not observed in the high-pain group. Knee flexion angle at heel strike correlated negatively with the gap between static femorotibial angle and peak KAA in the high-pain group. ConclusionsAlthough a direct correlation between subjective pain and peak KAM or KAA was not observed, our results suggest a compensatory movement in the high-pain group of participants to reduce KAA increases in the early stance phase. Such movements would be one of the reasons why it is difficult to obtain a consistent relationship between subjective pain and load-related parameters.

Association between stages of medial compartment osteoarthritis and three-dimensional knee alignment in the supine position: A cross-sectional study

BackgroundOsteoarthritis (OA) of the knee causes changes in knee alignment. A detailed knowledge of knee alignment is needed for correct assessment of the extent of disease progression, determination of treatment strategy, and confirmation of treatment effectiveness. However, deterioration of knee alignment during progression of OA has not been adequately characterized. The aims of this study were to clarify the changes in three-dimensional static knee alignment as knee OA stage progressed and to lay a foundation for an optimal treatment strategy to prevent knee malalignment. MethodsA total of 106 knees of 81 patients ((men/women) 45/36; mean age 48.4 ± 19.9 years; body mass index (BMI) 25.7 ± 4.4 kg/m2) were enrolled in this cross-sectional study, comprising 34 (33/1) in Kellgren-Lawrence (KL) grade 0, 17 (8/9) in KL grade 1, 26 (5/21) in KL grade 2, 19 (4/15) in KL grade 3, and 10 (1/9) in KL grade 4. In all cases, computed tomography images were obtained with the subject in a reclined and relaxed position with the knee straight. Three-dimensional bone models were created from the images and knee alignment was calculated with six degrees-of-freedom. Then, 40 knees were selected consisting of 10 sex- and BMI-matched knees from each KL grade group: KL grade 1 (mean age 54.6 ± 8.4 years; BMI 23.3 ± 3.5 kg/m2), grade 2 (64.7 ± 10.9 years; 27.3 ± 3.2 kg/m2), grade 3 (69.2 ± 11.4 years; 27.1 ± 4.3 kg/m2), and grade 4 (71.9 ± 9.2 years; 27.2 ± 3.6 kg/m2). The Mann–Whitney U test with Bonferroni correction for multiple comparisons was used to analyze static alignment (α < 0.05/6). ResultsAlignment of the knee in flexion was -4.0 [95% confidence interval (CI): -6.4, -1.5] degrees, -3.4 [-8.0, 1.3] degrees, -0.1 [-3.7, 3.5] degrees, and 0.4 [-0.9, 1.6] degrees in the order of KL grade 1 to 4. There were significant differences between KL grade 1 and 4 (p = 0.0081). Anterior tibial translation was 6.6 [4.6, 8.6] mm, 5.8 [1.9, 9.7] mm, 1.0 [-2.5, 4.5] mm, and 1.3 [-2.4, 5.1] mm in the order of grade 1 to 4. There were significant differences between KL grade 1 and 4 (p = 0.0081). There were no significant differences in lateral tibial translation nor tibial rotation. ConclusionsThe severely osteoarthritic knee joint was flexed and the tibia was displaced posteriorly with respect to the femur. Preventing these changes in alignment would assist in the prevention and treatment of knee OA.

Kinematic analyses including finite helical axes of drop jump landings demonstrate decreased knee control long after anterior cruciate ligament injury.

The purpose was to evaluate the dynamic knee control during a drop jump test following injury of the anterior cruciate ligament injury (ACL) using finite helical axes. Persons injured 17–28 years ago, treated with either physiotherapy (ACLPT, n = 23) or reconstruction and physiotherapy (ACLR, n = 28) and asymptomatic controls (CTRL, n = 22) performed a drop jump test, while kinematics were registered by motion capture. We analysed the Preparation phase (from maximal knee extension during flight until 50 ms post-touchdown) followed by an Action phase (until maximal knee flexion post-touchdown). Range of knee motion (RoM), and the length of each phase (Duration) were computed. The finite knee helical axis was analysed for momentary intervals of ~15° of knee motion by its intersection (ΔAP position) and inclination (ΔAP Inclination) with the knee’s Anterior-Posterior (AP) axis. Static knee laxity (KT100) and self-reported knee function (Lysholm score) were also assessed. The results showed that both phases were shorter for the ACL groups compared to controls (CTRL-ACLR: Duration 35±8 ms, p = 0.000, CTRL-ACLPT: 33±9 ms, p = 0.000) and involved less knee flexion (CTRL-ACLR: RoM 6.6±1.9°, p = 0.002, CTRL-ACLR: 7.5 ±2.0°, p = 0.001). Low RoM and Duration correlated significantly with worse knee function according to Lysholm and higher knee laxity according to KT-1000. Three finite helical axes were analysed. The ΔAP position for the first axis was most anterior in ACLPT compared to ACLR (ΔAP position -1, ACLPT-ACLR: 13±3 mm, p = 0.004), with correlations to KT-1000 (rho 0.316, p = 0.008), while the ΔAP inclination for the third axis was smaller in the ACLPT group compared to controls (ΔAP inclination -3 ACLPT-CTRL: -13±5°, p = 0.004) and showed a significant side difference in ACL injured groups during Action (Injured-Non-injured: 8±2.7°, p = 0.006). Small ΔAP inclination -3 correlated with low Lysholm (rho 0.391, p = 0.002) and high KT-1000 (rho -0.450, p = 0.001).Conclusions Compensatory movement strategies seem to be used to protect the injured knee during landing. A decreased ΔAP inclination in injured knees during Action suggests that the dynamic knee control may remain compromised even long after injury.

Effects of Taping and Balance Exercises on Knee and Lower-Extremity Function in Amateur Soccer Players: A Randomized Controlled Trial.

Knee injury prevention is a critical aspect in sport rehabilitation sciences, and taping is a widely used technique in this field. Nevertheless, the role and effectiveness of a long-term application of Kinesio Taping (KT) on knee function, disability, and injury prevention remain unclear. To determine the effect of KT, alone or in combination with balance exercises (BE), on dynamic and static knee balance and flexibility. Randomized trial design. University of Valencia (Spain). Forty-eight male amateur soccer players. Participants were assigned to 3 groups: Sham KT (sKT) + BE, KT + BE, and KT in isolation. The intervention period lasted 4 weeks. Three evaluations were performed: at baseline (pre), at 2 weeks (mid), and at 4 weeks posttreatment (post). Y Balance Test, unipedal stance test, the toe touch test, and the Knee Injury and Osteoarthritis Outcome Score. Both sKT + BE and KT + BE groups achieved significant pre-post improvements in SEBT, unipedal stance test, and toe touch test. The KT group only showed significant intragroup differences in the left and right unipedal stance test variable (P < .05, d = 0.76, d = 0.62, respectively). The sham KT group obtained the strongest results in all physical variables. Regarding the Knee Injury and Osteoarthritis Outcome Score, pre-post significant changes were found in the sham group (P < .05, d = 0.28). Both sham and real KT in combination with BE achieved significant improvements on all physical variables, and these differences were significantly greater compared with those found in the KT in the isolation group, suggesting that benefits in knee function are due to the BE. Therapy level 1b.