Maximum Knee Flexion Angle Research Articles

Standing Long Jump Performance Is Enhanced When Using an External as Well as Holistic Focus of Attention: A Kinematic Study.

Standing long jump is known as one of the important skills in the success of athletes in most sports. In addition, one of the most effective factors that can affect standing long jump distance and kinematics is the focus of attention used by the athlete. Therefore, the aim of the present study was to compare the effect of internal, external, and holistic focus of attention instructions on standing long jump performance and kinematics. The participants were 30 novices (all males; mean age = 21.70 ± 2.21 years; mean height = 175.73 ± 6.09 cm; and mean weight = 73.76 ± 11.77 kg) who performed 12 standing long jumps in four focus of attention conditions. Internal focus, external focus, holistic focus, and control conditions were implemented in a counterbalanced order. Jump distance and maximum knee flexion angle before take-off were recorded in all trials. The results showed that in relation to the standing long jump performance, the distance was similar in external and holistic focus conditions, and both were superior to internal or control conditions. There was no difference between control and internal focus of attention conditions. The results related to movement kinematics, however, did not report a difference between the maximum flexion angles before take-off. This study replicates the benefits of external and holistic focus instructions for jump distance, but this difference was not a product of different maximum knee flexion angles. It is suggested that coaches implement external and/or holistic focus cues to maximize athlete performance in jumping tasks.

Nalbuphine versus morphine: an adjuvant to spinal anesthesia for controlling pain after total knee arthroplasty: a propensity score-matched analysis.

Nalbuphine, a synthetic k-agonist and µ-antagonist, provides efficient pain relief while reducing opioid-related adverse effects. This study aims to compare the efficacy of intrathecal nalbuphine (ITN) with intrathecal morphine (ITM) for post-TKA pain. A retrospective cohort analysis of 131 patients who underwent TKA with spinal anesthesia (SA), a single shot of adductor canal block, and periarticular injections was conducted. The patients were divided into 2 groups, Group N received 0.8mg nalbuphine, and Group M received 0.2mg morphine as an adjuvant to SA. Propensity-score matching was employed to compare the visual analog scales (VAS) of postoperative pain intensity, cumulative morphine use (CMU), maximum knee flexion angle, straight leg raise (SLR) ability, incidence of postoperative nausea and vomiting (PONV), and length of hospital stay (LHS). The mean VAS of group M were significantly lower than group N at 6, 12, 18, and 24h (P < 0.01). Group M had lower CMU than group N at 24h (P < 0.01) and 48h (P < 0.01), while there was no significant difference between groups in terms of knee flexion angle and SLR at any time point. Additionally, 29.3 and 57.9% of patients in group N and M experienced PONV, respectively (p = 0.04), and group N had significantly shorter LHS compared to group M (P < 0.001). Although, intrathecal morphine (ITM) still provides better pain control particularly in the first 24h, patients who received intrathecal nalbuphine (ITN) had significantly fewer incidence of PONV, and shorter LHS.

Effects of 16weeks of plyometric training on knee biomechanics during the landing phase in athletes.

This study investigated the effects of plyometric training on lower-limb muscle strength and knee biomechanical characteristics during the landing phase. Twenty-four male subjects were recruited for this study with a randomised controlled design. They were randomly divided into a plyometric training group and a traditional training group and underwent training for 16weeks. Each subject was evaluated every 8weeks for knee and hip isokinetic muscle strength as well as knee kinematics and kinetics during landing. The results indicated significant group and time interaction effects for knee extension strength (F=74.942 and p=0.001), hip extension strength (F=99.763 and p=0.000) and hip flexion strength (F=182.922 and p=0.000). For landing kinematics, there were significant group main effects for knee flexion angle range (F=4.429 and p=0.047), significant time main effects for valgus angle (F=6.502 and p=0.011) and significant group and time interaction effects for internal rotation angle range (F=5.475 and p=0.008). The group main effect for maximum knee flexion angle was significant (F=7.534 and p=0.012), and the group and time interaction effect for maximum internal rotation angle was significant (F=15.737 and p=0.001). For landing kinetics, the group main effect of the loading rate was significant (F=4.576 and p=0.044). Significant group and time interaction effects were observed for knee extension moment at the moment of maximum vertical ground reaction force (F=5.095 and p=0.010) and for abduction moment (F=8.250 and p=0.001). These findings suggest that plyometric training leads to greater improvements in hip and knee muscle strength and beneficial changes in knee biomechanics during landing compared to traditional training.

ROBOTIC-ASSISTED TOTAL KNEE ARTHROPLASTY IS ASSOCIATED WITH EARLIER RETURN OF SYMMETRICAL LIMB FUNCTION COMPARED WITH CONVENTIONAL TOTAL KNEE ARTHROPLASTY

IntroductionRobotic-assisted total knee arthroplasty (TKA) has demonstrated significant benefits, including improved accuracy of component positioning compared to conventional jig-based TKA. However, previous studies have often failed to associate these findings with clinically significant improvements in patient-reported outcome measures (PROMs). Inertial measurement units (IMUs) provide a more nuanced assessment of a patient's functional recovery after TKA. This study aims to compare outcomes of patients undergoing robotic-assisted and conventional TKA in the early postoperative period using conventional PROMS and wearable sensors.Method100 patients with symptomatic end-stage knee osteoarthritis undergoing primary TKA were included in this study (44 robotic-assisted TKA and 56 conventional TKA). Functional outcomes were assessed using ankle-worn IMUs and PROMs. IMU- based outcomes included impact load, impact asymmetry, maximum knee flexion angle, and bone stimulus. PROMs, including Oxford Knee Score (OKS), EuroQol-Five Dimension (EQ-5D-5L), EuroQol Visual Analogue Scale (EQ-VAS), and Forgotten Joint Score (FJS-12) were evaluated at preoperative baseline, weeks 2 to 6 postoperatively, and at 3-month postoperative follow-up.ResultsBy postoperative week 6, when compared to conventional TKA, robotic-assisted TKA was associated with significant improvements in maximum knee flexion angle (118o ± 6.6 vs. 113o ± 5.4; p=0.04), symmetrical loading of limbs (82.3% vs.22.4%; p&lt;0.01), cumulative impact load (146.6% vs 37%; p&lt;0.01), and bone stimulus (25.1% vs 13.6%; p&lt;0.01). Whilst there were no significant differences in PROMs (OKS, EQ-5D-5L, EQ-VAS, and FJS-12) at any time point between the two groups, when comparing OKS subscales, significantly more robotic-assisted TKA patients achieved an ‘excellent’ outcome at 6 weeks compared to conventional (47% vs 41%, p= 0.013).ConclusionsIMU-based metrics detected an earlier return to function among patients that underwent robotic-assisted TKA compared to conventional TKA that PROMs were unable to detect within the first six weeks of surgery.

Kinematics of 90° change of direction in young football players: Insights for ACL injury prevention from the CUTtheACLstudy on 6008 trials.

To investigate the 90° change of direction (COD) task in an extensive cohort of competitive healthy football players within the CUTtheACLstudy and to provide normative values and differences between males and females for full-body kinematics based on two-dimensional (2D) video analysis and scoring system. One-thousand-and-two competitive football (soccer) players (age 16.3 ± 2.8 years, 264 females) were prospectively enroled. Each player performed three preplanned 90° COD tasks per limb. The 2D evaluation was performed through objective measures (collected through three high-speed cameras) of frontal and sagittal plane joint kinematics at the cut initial foot contact (IC) and maximum knee flexion angle. A previously published scoring system was adopted to measure the movement quality of the COD task. The scoring system included five criteria (limb stability [LS], pelvis stability [PS], trunk stability [TS], shock absorption [SA], movement strategy [MS]) ranked from 0/2 (nonadequate) to 2/2 (adequate) with a maximum score of 10/10. Normative data were provided for all the variables; statistical differences between male and female players were investigated (p < 0.05). A total of 6008 valid attempts were included. Frontal plane knee projection angle (FPKPA) at initial contact was 24.4 ± 9.8° (95thpercentile: FPKPA > 40°). The total score was ≤4/10 in 71.2% of the trials, the lowest subscores were LS and PS. Female players showed different movement patterns with lower hip and trunk flexion both at IC and maximum knee flexion angle (p < 0.01, ES = 0.41-0.64). Female players also showed worse scores than males in SA, MSand total score (p < 0.01). Female players seem more prone to stiffer lower limb strategy and greater pelvis-trunk frontal plane instability than males. Clinicians could adopt normative data and sex-specific differences in players' movement techniques to improve ACL injury risk mitigation protocols. Level IV.

A Biomechanical Comparison Between the Safety-Squat Bar and Traditional Barbell Back Squat.

Johansson, DG, Marchetti, PH, Stecyk, SD, and Flanagan, SP. A biomechanical comparison between the safety-squat bar and traditional barbell back squat. J Strength Cond Res 38(5): 825-834, 2024-The primary objectives for this investigation were to compare the kinematic and kinetic differences between performing a parallel back squat using a traditional barbell (TB) or a safety-squat bar (SSB). Fifteen healthy, recreationally trained male subjects (23 + 4 years of age) performed the back squat with a TB and an SSB at 85% of their respective 1 repetition maximum with each barbell while instrumented for biomechanical analysis. Standard inverse dynamics techniques were used to determine joint kinematic and kinetic measures. A 2 × 3 (exercise × joint) factorial analysis of variance with repeated measures was used to determine the kinetic and kinematic differences between the squats while using the different barbells. Fisher's least significant difference post hoc comparisons showed that the TB resulted in significantly greater maximum hip flexion angle (129.33 ± 11.8° vs. 122.11 ± 12.1°; p < 0.001; d = 1.80), peak hip net joint extensor torque (2.54 ± 0.4 Nm·kg -1 vs. 2.40 ± 0.4 Nm·kg -1 ; p = 0.001; d = 1.10), hip net extensor torque mechanical energy expenditure (MEE; 2.81 ± 0.5 Nm·kg -1 vs. 2.58 ± 0.6 Nm·kg -1 ; p = 0.002; d = 0.97), and ankle net joint plantar flexor torque MEE (0.32 ± 0.09 J·kg -1 vs. 0.28 ± 0.06 J·kg -1 ; p = 0.029; d = 0.63), while also lifting significantly (123.17 ± 20.8 kg vs. 117.17 ± 20.8 kg; p = 0.005; d = 0.858) more weight than the SSB. The SSB resulted in significantly higher maximum knee flexion angles (116.82 ± 5.8° vs. 115.65 ± 5.6°; p = 0.011; d = 0.75) than the TB, with no significant difference in kinetics at the knee. The TB may be preferred to the SSB for developing the hip extensors and lifting higher maximum loads. The SSB may be advantageous in situations where a more upright posture or a lower load is preferred while creating a similar demand for the knee joint.

Development of four-bar polycentric knee joint with stance-phase knee flexion

A conventional 4-bar polycentric knee and solid ankle cushion heel foot (SACH foot) have been commonly used in developing countries. However, they cannot perform stance-phase knee flexion, which makes a person with an amputation walk unnaturally and with less stability. This research proposes a novel design of a 4-bar polycentric knee with stance-phase knee flexion ability (4BSF), which can perform both stance and swing-phase knee flexion, like able-bodied gait. In the proposed conceptual design, the instantaneous center of rotation (ICR) path is repositioned during the stance phase. The ICR was placed in front of the ground reaction force (GRF) to initiate knee flexion during the loading response. The prototype was validated by a single-subject pilot study at the Gait analysis laboratory. The results showed that a person with an amputation walks with stance-phase knee flexion using the proposed 4BSF. The maximum knee flexion angle is more than 10° during the stance phase. Furthermore, when the 4BSF was used with a SACH foot, the amount of time to achieve the foot flat was shorter, and the foot flat duration time was twice as long as the conventional 4-bar polycentric knee.

Preserved posterior cruciate ligament contributed to knee sagittal stability, but not to rollback and deep knee flexion in cruciate-retaining total knee arthroplasty with a cruciate-substituting insert

PurposeNo previous report has compared the differences in postoperative functional outcomes between posterior cruciate ligament (PCL)-retaining (CR-) and PCL-sacrificing (CS-) total knee arthroplasty (TKA) with detailed intraoperative consideration of joint gap and balance. The purpose of this study was to evaluate the in vivo function of preserved PCL in TKA by comparing postoperative functional outcomes between CR- and CS-TKA with a cruciate-substituting insert (CS-insert), considering intraoperative influence factors, such as the posterior tibial slope, posterior condylar offset, joint gap, joint balance, and joint laxity. MethodsA total of 55 knees in 38 patients (27 knees from 18 patients in the CR group, and 28 knees from 20 patients in the CS group) were analyzed. Fluoroscopic evaluation under anesthesia in sagittal laxity, rollback amount, and the maximum flexion angles were compared between the groups. ResultsThere were no significant differences in intraoperative or postoperative all measurement values between the two groups, but the sagittal laxity was significantly smaller in the CR group [5.4% ± 4.5% (2.4 ± 2.1 mm)] than in the CS group [9.0 ± 3.8% (4.0 ± 1.7 mm)] (P ​< 0.01). There were no significant differences in the amount of rollback and postoperative maximum knee flexion angle between the groups. ConclusionsPreserved PCL in TKA with a CS-insert contributed to knee sagittal stability, but not to rollback and deep knee flexion.

Sex-Based Differences in Lower Extremity Kinematics During Dynamic Jump Landing Tasks After Neuromuscular Fatigue of the Hip Extensors and Knee Flexors.

Neuromuscular fatigue can increase the activation of antagonist muscles, thereby reducing the moment produced by the agonist. During the deceleration phase of landing, hip extensor and knee flexor muscles contract eccentrically to counteract the external hip flexion moment. Decreased hip flexion is associated with greater knee extensor moments and risk of injury. To investigate sex-based differences in kinematics and muscle activity after neuromuscular fatigue of the hip extensors and knee flexors during dynamic single-leg tasks. Controlled laboratory study. In this study, 9 female (age, 22.3 ± 3.4 years) and 7 male participants (age, 21.3 ± 2.6 years) completed the triple hop (THop) for distance and single-leg drop-jump (SJump) tasks before and after a fatigue protocol consisting of eccentric hip extension and knee flexion. Motion capture and electromyography were used to compare lower extremity kinematics and muscular activation between the sexes. During the THop, neuromuscular fatigue resulted in significantly decreased maximum hip flexion angles (P = .01), maximum knee flexion angles (P = .039), and an effect of sex on all hip flexion angles, where both sexes saw decreased hip flexion postfatigue (P = .033). A significant interaction of fatigue and sex on hip flexion angular velocity was observed during the SJump, indicating that men experienced an increase while women experienced a decrease in hip flexion angular velocities due to fatigue (P = .03). Gluteus maximus activation was increased, and erector spinae activation was decreased postfatigue in women during the THop (P = .053 and P = .023, respectively). Results indicate that men and women compensated differently after fatigue of the hip extensors and knee flexors. Women more commonly assumed an erect landing posture associated with increased injury risk after fatigue of the hip extensors and knee flexors.

Influence of a football match on landing biomechanics and jump performance in female football players.

This study aimed to assess the acute effect of a competitive football match on jump performance and kinematic parameters during jump landing in semiprofessional female football players. Twenty-two semiprofessional players (20 ± 3 years) underwent a drop jump task for a posterior video analysis of the landing phase. These measurements were obtained at (1) baseline, (2) after, and (3) 48 h after a competitive football match. A one-way ANOVA with repeated measures was employed to detect differences over the time. There was a main effect of time for maximal knee flexion angle during drop landing (p = 0.001). In comparison with baseline, maximal knee flexion angle was reduced immediately post-match and was still reduced 48 h after the match (63.4 ± 8.6 vs 57.0 ± 11.7 vs 48.9 ± 19.1, p ≤ 0.038). There was also a main effect of time for drop jump height (p < 0.001). Drop jump height was reduced immediately post-match and remained low 48 h after the match in comparison with baseline (27.3 ± 3.6 vs 24.5 ± 2.8 ~ 25.5 ± 3.0 cm, p ≤ 0.002). There was a main effect of time on hip flexion angle during landing (p = 0.001), but the pairwise comparison revealed that this variable was not affected immediately post-match but was lower 48 h after the match than at baseline (50.1 ± 10.1 ~ 50.8 ± 13.2 vs 38.1 ± 17.8 °, p ≤ 0.005). A competitive football match worsened jump performance and several landing biomechanical parameters in female football players, which were still decreased in comparison with baseline even 48 h after the match.

Biomechanics research on laterality effect between dominant and non-dominant during double roundhouse kick in the competitive taekwondo

BackgroundThe Double Roundhouse Kick (DRK) is one of the major scoring tools and athletes employ the leg of the dominant side (DS) or the non-dominant side (NS) for always attacking in an alternating state. The purpose is to examine the discrepancies in the biomechanical characteristics of the DS and NS of the leg of the DRK skills of sub-elite taekwondo athletes. MethodsUsing the Vicon, Kistler, and Daedo brand Electronic Body Protector (EBP), collection of the DRK data (attack time, joint angle, joint angular velocity, joint moment, ground reaction force, etc.) of 12 sub-elite taekwondo athletes (19.6 ± 2.0 yr, 180 ± 7.3 cm, 70 ± 9.8 kg) with the DS leg and NS leg. The measured data analyses via Visual3D, and statistical methods using nonparametric tests paired with samples based on the Wilcoxon signed-rank test (The significance level is set as significant for P<0.05, and very significant for P<0.01). Results(i) There is no statistically significant discrepancy between the DS and NS at the time of hit (P>0.05) and shift of the center of gravity (P>0.05). (ii) Attacking leg (AL): the maximum knee flexion angle (Knee-MFA) (P<0.05) and the peak linear velocity of attack of the foot in the vertical hitting direction (P<0.01) on the DS was greater than that on the NS during the first hit phase (P1). (iii) Supporting leg (SL): the peak hip extension moment (P<0.05) on the DS was reported to be higher than that of the NS during the second hit phase (P2). (iv) Symmetry Index (SI): In the P1, the vertical ground reaction force (vGRF) of the SL leads to SI = 10.19 %, and in the P2, the vGRF of the SL results in SI = 18.48 %. ConclusionsThe DRK requires more and more symmetry between the DS and NS. The Knee-MFA of the AL and the line of attack speed of the foot in the vertical striking direction of the SL exhibited significant discrepancies. The DS has higher striking speed, athletes need to improve the striking speed of the NS leg in training, achieving more scoring opportunities in the game. Both the DS and NS revealed strong symmetry in the peak SI of the ground reaction force of the SL stirrup; however, weak symmetry was attained in the peak SI of the vGRF of the SL landing cushion.

Comparison of mechanical energy transfer during right-forward lunge between female amateur and professional badminton players

BackgroundRegarding their skill levels, badminton players present different movement patterns during front and right lunging. The main objective of this study was to compare the mechanical energy transfers attributable to right-forward lunges between amateur and professional badminton players to study variations in mechanical efficiency at various skill levels.MethodIn this cross-sectional study, twenty female badminton players were recruited (Professional group n = 10 and Amateur group n = 10). The kinematics and kinetics of the lower extremities were recorded while performing right-forward lunges using Vicon motion capture and Kistler force plates. Mechanical energy expenditures (MEE) were extracted in eccentric transfer, concentric transfer, and no-transfer phases for the hip, knee, and ankle joints. At each joint, mechanical energy compensations (MEC) were also determined. Independent samples t-tests were used to analyze data at a significance level of α = 0.05.ResultRegards to mechanical energy expenditures at the initial heel contact phase, the professional players demonstrated statistically significant more ankle no-transfer (p < 0.003), less knee concentric transfer (p < 0.026), more knee eccentric transfer (p < 0.001), and less hip no-transfer (p < 0.001). At the same time, the amateur athletes showed significantly more ankle eccentric transfer (p < 0.042) at maximal knee flexion angle time point. Analyzing mechanical energy compensation coefficients showed that the professional athletes had significantly less ankle concentric transfer (p < 0.001), more knee concentric transfer (p < 0.001), more knee eccentric transfer (p < 0.001), and more hip eccentric transfer (p < 0.001) at initial contact phase. While they found to have significantly more ankle eccentric transfer (p < 0.007), less knee concentric transfer (p < 0.001), less knee eccentric transfer (p < 0.001), more hip concentric transfer (p < 0.001), and more hip eccentric transfer (p < 0.001) at maximal knee flexion angle.Conclusionit is shown that the mechanical energy efficiency of the right-forward lunge is skill-related. It seems that altered lunge landing biomechanics may increase the risk of ankle and knee injuries and muscular damages in amateur athletes. It is recommended for amateur players to follow a injury prevention training program that promotes proper lunging technique.

Association of Dynamic Knee Valgus and Bone Stress Injury in US Military Academy Cadets.

Early identification of incoming military personnel at elevated odds for bone stress injury (BSI) is important for the health and readiness of the US military. Prospective cohort study. Knee kinematic data of the incoming US Military Academy cadets were collected while performing a jump-landing task (The Landing Error Scoring System) using a markerless motion capture system and depth camera. Data on incidence of lower-extremity injury, including BSI, were collected throughout the study period. A total of 1905 participants (452 females, 23.7%) were examined for knee valgus and BSI status. A total of 50 BSI occurred during the study period (incidence proportion = 2.6%). The unadjusted odds ratio for BSI at initial contact was 1.03 (95% confidence interval [CI], 0.94-1.14; P = .49). Adjusted for sex, the odds ratio for BSI at initial contact was 0.97 (95% CI, 0.87-1.06; P = .47). At the instant of maximum knee-flexion angle, the unadjusted odds ratio was 1.06 (95% CI, 1.02-1.10; P = .01), and the odds ratio was 1.02 (95% CI, 0.98-1.07; P = .29) after adjusting for sex. This suggests that there was not a significant enough association for an increase in the odds of BSI based on either degree of knee valgus. Our results did not demonstrate an association between knee valgus angle data during a jump-landing task and future increased odds of BSI in a military training population. Further analysis is warranted, but the results suggests the association between kinematics and BSI cannot be effectively screened by knee valgus angle data in isolation.

Joint kinematic and kinetic responses to added mass on the lower extremities during running

AimWe analyzed the biomechanical response (joint angles, moments, and powers) to running with added leg mass. These data may help guide the design of wearable locomotor assistive devices (i.e., exoskeletons), which are becoming more prevalent. Methods15 participants (7 females, 8 males) completed treadmill running trials (3m•s−1) normally and with lead mass (300–1350 g) attached to the thigh, shank, or foot, bilaterally. We quantified the lower limb biomechanics combining motion capture and ground reaction force data using standard inverse dynamics analysis. ResultsOnly moderate kinematic changes occurred in response to the distal added limb mass. Maximum hip flexion and maximum knee flexion angles during swing phase increased by approximately 9% and 6% respectively for each 1 kg added to each foot. However, adding even small masses made dramatic changes to the joint moments and powers, mostly during the swing phase. For example, adding 1 kg to each foot increased maximum joint moments by as much as 40% (knee extension in late swing) and maximum joint power by as much as 50% (hip generation in late swing). ConclusionLeg joint kinematics were largely conserved in response to adding mass to the legs. Adding mass to the leg distally increased joint power mainly at the knee and hip joints during the swing phase, whereas adding mass proximally mainly affected the ankle joint mechanics during the stance phase. These changes have implications for shoe designs, people who run with added mass on their legs for sport/strength training and for the design of wearable devices.

Spatiotemporal and kinematic gait analysis in patients with knee osteoarthritis and femoral varus deformity

BackgroundKnee osteoarthritis (OA) is commonly combined with the presentation of a coronal deformity of the knee. The bony origin of the knee varus deformity can be classified as tibial origin, femoral origin, or a combination of tibial and femoral causes. Deformities of tibial origin are mostly common clinically, while patients with knee OA with femoral varus deformity are less common. Research questionDo hip, knee and ankle kinematics and spatiotemporal parameters differ between patients with knee OA with femoral varus deformity and healthy subjects? MethodsTwenty-five patients (14 females and 11 males) with knee OA and femoral varus deformity and 20 healthy subjects (12 males and 8 females) as control group were included in this study. The kinematic parameters of the hip-knee-ankle joint and spatiotemporal gait parameters were included in the study. ResultsThis study found that the step speed and step length of the knee OA with femoral varus (KOAF) group were smaller than those of the control group, while double support period percentage was greater in the KOAF group. Significant differences were found in the maximum knee extension angle, maximum knee flexion angle, knee flexion range of motion, maximum hip flexion angle, maximum hip extension angle, and hip flexion range of motion between the two groups. After comparing the ankle motion between the two groups, significant differences were found in the maximum eversion angle, inversion range of motion, maximum ankle abduction angle, and abduction range of motion. SignificanceKnee OA with femoral varus deformity causes adaptive changes in the kinematic parameters of hip, knee and ankle joints and spatiotemporal gait parameters to alleviate symptoms and maintain normal activity.

Gross Appearances of the Posterior Cruciate Ligament Correlate With Its Histological Features but not With In Vivo Function in Cruciate-Retaining Total Knee Arthroplasty.

Background No study has evaluated whether the macroscopic appearance or histological features of the posterior cruciate ligament (PCL) affect the in vivo PCL function in cruciate-retaining (CR) total knee arthroplasty (TKA). The aim of this study is to elucidate the correlation between intraoperative gross appearances of the PCL and clinical parameters, their corresponding histological features, and the in vivo function. Methods The intraoperative gross appearances of the PCLs were evaluated; we also examined their correlations with clinical parameters, corresponding histological features, and the in vivo function in CR-TKA. Results There were significant correlations between intraoperative gross appearances of the PCL and that of the anterior cruciate ligament, the preoperative knee flexion angle, and the intercondylar notch stenosis. There was a significant correlation between the intraoperative gross appearance in the middle part and the corresponding histological features. However, there was no significant correlation between the intraoperative gross appearance or histological features and the PCL tension, amount of rollback, and maximum knee flexion angle. Conclusions The intraoperative gross appearance of the PCL correlated with clinical parameters. Also, there was a significant correlation between the intraoperative gross appearance in the middle part and the corresponding histological features; however, there was no correlation between the intraoperative gross appearance or histological features and the in vivo function.

무릎 신전근 피로 수준이 외발 드롭 착지 시 무릎 관절 안정성에 미치는 영향

This study was to investigate the effect of experimentally induced knee extensor muscle fatigue on biomechanical variables related to knee stability during landing after a drop jump. Methods: A total of 14 young men participated voluntarily. As for the fatigue induction method, isokinetic equipment (Biodex System 4, Biodex Medical Systems, Inc. USA) was used, Kinematic data of the lower limbs were collected using a 3D Motion Analysis Eagle system (EVART 4.6, Santa Rosa, CA, USA) connected to 12 cameras at a sampling rate of 200 Hz, and ground reaction forces were obtained using an AMTI OR6-5 force platform (Watertown, MA, USA) was used to collect at a sampling rate of 1200 Hz. Results: The maximum knee flexion angle during one-leg drop landing was significantly increased after fatigue induction than before fatigue induction, but there was no significant difference among the fatigue induction conditions in knee valgus and varus, lateral rotation and medial rotation during one-leg drop landing. The shear stress in the tibia showed a tendency to increase according to the level of fatigue, but no significant difference was found. On the other hand, in the sagittal plane, the maximum knee joint moment was significantly decreased after fatigue induction, and the maximum ground reaction force was also found to be significantly decreased in the condition after fatigue induction compared to the condition before fatigue induction. Conclusion: Fatigue of the knee joint extensors following the fatigue protocol did not lead to significant changes in biomechanical variables related to knee stability. However, there was a significant decrease in maximum knee joint moment and maximum ground reaction force, and a significant increase in maximum knee joint angle during one-leg drop landing after fatigue induction. Therefore, the results of the study demonstrated that local fatigue (knee extensor fatigue exercise) according to the fatigue protocol did not affect biomechanical variables related to knee stability, but did affect biomechanical variables related to task performance.

Importance of Lower Extremity Muscle Performance and Knee Proprioception During First 60 Degrees of Knee Flexion at Three Months After Anterior Cruciate Ligament Reconstruction

Background: Knee proprioception and neuromuscular control may be important factors contributing to re-injury occurrences. Objectives: To examine lower extremity muscular performance and knee proprioception preoperatively and 3 months after anterior cruciate ligament (ACL) reconstruction. Methods: Twelve participants underwent ACL reconstruction using the hamstring tendon. All participants were assessed for knee proprioceptive sense using an isokinetic dynamometer at 15° and 60° of knee flexion. Lower extremity muscular performance was examined using the single-leg squat test (SLS) with two-dimensional motion analysis in frontal and sagittal planes. Results: Mean absolute error angle at a 15-degree-target angle was significantly lower at three months after ACL reconstruction compared with the preoperative state (P = 0.04). Maximal knee flexion angle of the injured The SLS test showed a lesser knee flexion angle of the injured knee at three months after ACL reconstruction (P = 0.01), and injured knee proprioception at 60 degree-flexion did not significantly improve at the three month-postoperative stage. Conclusions: At three months after ACL reconstruction by hamstring graft tendon, knee proprioceptive sense at an inner range of knee extension improved. However, proprioception at the middle range did not significantly develop. The range of hip and knee motions using SLS related to strength changes that the knee extensor needs to improve, especially in the middle range.

Comparison of Tibial Tubercle Landmark Technique and Range of Motion Technique in Primary Total Knee Arthroplasty: A Retrospective Cohort Study.

There is not a standard for rotational alignment of the tibial component in total knee arthroplasty (TKA). For now, the most commonly methods are tibial-tubercle -landmark technique (TTL) and range-of-motion technique (ROM). The study is aimed to compare clinical outcomes and radiographic data of patients who undergone primary TKA with TTL or ROM technique. This single-surgeon retrospective cohort study includes 60 patients with TTL technique and 60 with ROM technique from December 2017 to January 2019. All patients were evaluated clinically using Hospital for Special Surgery Knee Score (HSS), Feller patellar score, visual analogue scale (VAS) and maximum knee flexion and extension angle before and after surgery at both 6 months and 12months postoperatively. Radiographic data contain hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), posterior slope angle (PSA) on pre and postoperative X-ray and rotation angle of femoral component (relative to surgical trans-epicondylar axis) and tibial component (relative to surgical trans-epicondylar axis, tibial posterior condylar line and Akagi') on postoperative computed tomography (CT) scan. Clinical outcomes and radiological data were compared between the two groups. One hundred twenty patients (120 knees) were enrolled in this study, including 38 males and 82 females, aged from 58 to 78, with an average of 65.7 years. There was no significant difference in demographics and preoperative X-ray data between the two groups (P > 0. 05). Clinical scores of the TTL group were better than those in the ROM group at 6 and 12months after surgery, when comparing HSS (83.57 ± 5.00 vs 75.90 ± 4.89, F=59.004, P < 0.001; 90.53 ± 4.31 vs 82.83 ± 4.98, F=54.509, P < 0.001), Feller patellar score (21.43 ± 2.54 vs 19.10 ± 2.52, F=14.864, P=0.001; 26.27 ± 1.98 vs 23.20 ± 2.31, F=42.204, P < 0.001) and VAS (3.70 ± 0.62 vs 4.38 ± 0.92, F=14.508, P=0.001; 2.10 ± 0.90 vs 2.79 ± 0.80, F=11.554, P=0.002). But there was no significant difference in the flexion and extension angle between the two groups. In imaging evaluation, no statistical difference was found in pre- and postoperative HKA, mLDFA, mMPTA and PSA. Rotational angles of tibial component only did relative to Akagi' have statistical difference in two groups (2.33 ± 4.3 vs 4.41 ± 3.2, t=2.143, P < 0.05) (Positive value represented external rotation). The results of our study showed that both methods were reliable, and TTL technique provided better clinical scores and larger external angle of tibial component, compared to ROM technique.

Effects of flat-flexible shoes on lower limb joint kinetics and kinematics in gait

Flat-flexible shoes with unique characteristics, such as low pitch and flexibility, can increase the efficiency of ankle energy and running performance. If flat-flexible shoes have the same effect during walking, they could be used for gait training. This study aimed to investigate the effects of flat-flexible shoes on the kinematics and kinetics of the lower limb. Twenty-one healthy young adults (21.8 ± 4.6 years) participated in this study. The participants wore flat-flexible and standard athletic shoes with reflective markers attached according to the Plug-in-Gait model. Walking motion was recorded using infrared cameras and a treadmill embedded with force plates. The angle(s), moment(s), and power(s) of the ankle, knee, and hip joints were calculated. Paired t-test and Wilcoxon’s signed-rank test were used to compare the parameters between the two footwear types. The use of flat-flexible shoes increased maximum ankle dorsiflexion and knee flexion angles. The maximum ankle plantar flexion angle was significantly reduced. There was no significant difference in the joint moment between the two footwear types. The peaks of ankle power absorption in late stance, ankle power generation, and hip power generation significantly increased with the use of flat-flexible shoes. These results suggest that flat-flexible shoes have potential as a tool to promote ankle energy storage and release during gait.