Knee Varus Moment Research Articles

The effect of performance demands on lower extremity biomechanics during landing and cutting tasks

BackgroundAnterior cruciate ligament (ACL) injuries commonly occur during the early phase of landing and cutting tasks that involve sudden decelerations. The purpose of this study was to investigate the effects of jump height and jump speed on lower extremity biomechanics during a stop-jump task and the effect of cutting speed on lower extremity biomechanics during a side-cutting task. MethodsThirty-six recreational athletes performed a stop-jump task under 3 conditions: jumping fast, jumping for maximum height, and jumping for 60% of maximum height. Participants also performed a side-cutting task under 2 conditions: cutting at maximum speed and cutting at 60% of maximum speed. Three-dimensional kinematic and kinetic data were collected. ResultsThe jumping fast condition resulted in increased peak posterior ground reaction force (PPGRF), knee extension moment at PPGRF, and knee joint stiffness and decreased knee flexion angle compared with the jumping for maximum height condition. The jumping for 60% of maximum height condition resulted in decreased knee flexion angle compared with the jumping for maximum height condition. Participants demonstrated greater PPGRF, knee extension moment at PPGRF, knee valgus angle and varus moment at PPGRF, knee joint stiffness, and knee flexion angle during the cutting at maximum speed condition compared with the cutting at 60% maximum speed condition. ConclusionPerforming jump landing at an increased jump speed resulted in lower extremity movement patterns that have been previously associated with an increase in ACL loading. Cutting speed also affected lower extremity biomechanics. Jump speed and cutting speed need to be considered when designing ACL injury risk screening and injury prevention programs.

Motor learning strategies in basketball players and its implications for ACL injury prevention: a randomized controlled trial

PurposeAdding external focus of attention (EF, focus on the movement effect) may optimize current anterior cruciate ligament (ACL) injury prevention programmes. The purpose of the current study was to investigate the effects of an EF, by a visual stimulus and an internal focus, by a verbal stimulus during unexpected sidestep cutting in female and male athletes and how these effects remained over time.MethodsNinety experienced basketball athletes performed sidestep cutting manoeuvres in three sessions (S1, S2 and S3). In this randomized controlled trial, athletes were allocated to three groups: visual (VIS), verbal (VER) and control (CTRL). Kinematics and kinetics were collected at the time of peak knee frontal plane moment.ResultsMales in the VIS group showed a larger vertical ground reaction force (S1: 25.4 ± 3.1 N/kg, S2: 25.8 ± 2.9 N/kg, S3: 25.2 ± 3.2 N/kg) and knee flexion moments (S1: −3.8 ± 0.9 Nm/kg, S2: −4.0 ± 1.2 Nm/kg, S3: −3.9 ± 1.3 Nm/kg) compared to the males in the VER and CTRL groups and to the females in the VIS group (p < 0.05). Additionally, the males in the VIS group reduced knee valgus moment and the females in the VER group reduced knee varus moment over time (n.s.).ConclusionMale subjects clearly benefit from visual feedback. Females may need different feedback modes to learn a correct movement pattern. Sex-specific learning preferences may have to be acknowledged in day by day practice. Adding video instruction or feedback to regular training regimens when teaching athletes safe movement patterns and providing individual feedback might target suboptimal long-term results and optimize ACL injury prevention programmes.Level of evidenceI.

Effects of Arch Support Insoles on Gait Patterns of Patients with Knee Osteoarthritis

Although arch support orthotics are prescribed for knee osteoarthritis (OA) patients in clinics, the biomechanical effects of such devices are not fully clear. This study conducts an experimental investigation to evaluate the short-term effects of shoes with arch support insoles on the gait patterns of patients with knee OA during level walking. Twelve adults with knee OA were recruited, and biomechanical data were measured under three test conditions: walking barefoot, walking in shoes, and walking in shoes and insoles. Participants’ gait patterns were recorded and analyzed using a motion analysis system, Kistler force plates, and EVaRT software. Walking in shoes with insoles significantly increased the peak knee flexion angle and the peak dorsiflexion and external rotation angles of the ankle, but reduced the peak ankle internal rotation angle compared to those for walking barefoot. Both walking in shoes with insoles and walking in shoes significantly reduced the toe-out angle compared to that for walking barefoot. However, no significant difference was observed in the peak knee varus moment. The results suggest that the foot insoles and shoes tested in this study might have influenced the ankle joint in OA patients. In view of the significantly decreased toe-out angle of the foot and increasing trend in the knee varus moment, the use of shoes with insoles may be unsuitable for knee OA patients.

여자 농구 선수들의 착지 유형이 전방십자인대 손상위험 요인에 미치는 영향

The purpose of this study was to investigate the effects of landing tasks on the anterior cruciate ligament (ACL) injury risk factors in female basketball players. Fifteen female basketball players performed a drop landing and a drop landing with a vertical jump on the 40 cm height box. Three-dimensional motion analysis system and ground reaction force system was used for calculate the ACL injury risk factors. Paired samples t-test with Bonfferoni correction were performed. The drop landing with a vertical jump had the higher knee flexion angle, peak knee varus moment, trunk flexion angle than a drop landing. However, the drop landing had the higher trunk rotation angle than a drop landing with a vertical jump. These results indicate that seemingly minor variations between drop landing and drop landing with a vertical jump may influence the ACL injury risk factors. Caution should be used when comparing studies using different landing tasks.

Surgical Management of Persistent Intoeing Gait Due to Increased Internal Tibial Torsion in Children

Intoeing gait is frequently seen in developing children, and in most cases it resolves with growth. However, persistent, extreme intoeing gait, due to increased internal tibial torsion, may disrupt gait function. At our institution, children with symptomatic intoeing gait are evaluated per a standardized protocol, which includes quantitative gait analysis. When the primary cause is increased internal tibial torsion, surgical correction by supramalleolar tibial rotational osteotomy is recommended. The study design was a retrospective case series, with normative controls (31 children), of typically developing children with symptomatic intoeing gait who were treated by isolated supramalleolar tibial rotation osteotomy (28 children, with 45 treated extremities). Preoperative and 1-year postoperative physical examination, kinematic, kinetic, and pedobarographic data were compared. Patient-reported and parent-reported outcomes in functional and satisfaction domains were assessed by items on a 7-point questionnaire. Internal tibial torsion, foot progression angle, and knee rotation were normalized following tibial rotation osteotomy. Compensatory external hip rotation and external knee progression angle were significantly improved but not normalized following tibial rotation osteotomy. An increased coronal plane knee varus moment was significantly decreased following surgery. Increased sagittal and transverse plane knee moments were significantly decreased but not normalized following surgery. Significant improvements were observed with respect to tripping, falling, foot/ankle pain, and knee pain following surgery. Children with symptomatic intoeing gait because of increased internal tibial torsion have characteristic primary and compensatory kinematic gait deviations that result in increased loading about the knee during the stance phase of gait. Correction of the internal tibial torsion by rotation osteotomy improves, but does not normalize, all the kinematic and kinetic gait deviations associated with intoeing gait. The association between increased internal tibial torsion and degenerative arthritis of the knee in adults may be a consequence of longstanding increased loading of the knee joint due to the kinematic gait deviations seen with intoeing gait. Therapeutic intervention, level III.

Differences between opening versus closing high tibial osteotomy on clinical outcomes and gait analysis

BackgroundHigh tibial osteotomy (HTO) for medial knee osteoarthritis (OA) is mainly performed via two procedures: closing wedge HTO (CW) and opening wedge HTO (OW). In this study, differences between these procedures were assessed by serial clinical evaluation and gait analysis before and after surgery. MethodsTwenty-one patients underwent HTO for medial knee OA in 2011 and 2012, with 12 patients undergoing CW and nine undergoing OW. The severity of OA was classified according to the Kellgren–Lawrence classification. The Japanese Orthopedic Association score for assessment of knee OA (JOA score), the Numeric Rating Scale (NRS), and the femoral tibial angle (FTA) on X-ray were evaluated. For gait analysis, gait speed, varus moment, varus angle and lateral thrust were calculated. ResultsThe JOA score and NRS were improved significantly oneyear postoperatively in both groups. The FTA was maintained in both groups at oneyear. Varus angle and varus moment were significantly improved in both groups at each postoperative follow-up, when compared preoperatively. Lateral thrust was significantly improved at threemonths postoperatively in both groups. However, the significant improvement in lateral thrust had disappeared in the CW group sixmonths postoperatively, whereas it was maintained for at least oneyear in the OW group. ConclusionsThis study found that clinical outcomes were well maintained after HTO. OW reduced knee varus moment and lateral thrust, whereas CW had little effect on reducing lateral thrust. Level of evidenceLevel IV

Acute influence of restricted ankle dorsiflexion angle on knee joint mechanics during gait

BackgroundRestrictions in range of ankle dorsiflexion (DF) motion can persist following ankle injuries. Ankle DF is necessary during terminal stance of gait, and its restricted range may affect knee joint kinematics and kinetics. The purpose of this study was to investigate the acute influence of varied levels of restricted ankle DF on knee joint sagittal and frontal plane kinematics and kinetics during gait. MethodsThirty healthy volunteers walked with a custom-designed ankle brace that restricted ankle DF. Kinematics and kinetics were collected using a 7-camera motion analysis system and two force plates. Ankle dorsiflexion was restricted in 10-degree increments, allowing for four conditions: Free, light (LR), moderate (MR) and severe restriction (SR). Knee angles and moments were measured during terminal stance. ResultsReal peak ankle DF for Free, LR, MR, and SR were 13.7±4.8°, 11.6±5.0°, 7.5±5.3°, and 4.2±7.2°, respectively. Peak knee extension angles under the same conditions were −6.7±6.7°, −5.4±6.4°, −2.5±7.5°, and 0.6±7.8°, respectively, and the peak knee varus moment was 0.48±0.17Nm/kg, 0.47±0.17Nm/kg, 0.53±0.20Nm/kg, and 0.57±0.20Nm/kg. The knee varus moment was significantly increased from MR condition with an 8-degree restriction in ankle DF. ConclusionKnee joint kinematics and kinetics in the sagittal and frontal planes were affected by reduced ankle DF during terminal stance of gait. Differences were observed with restriction in ankle DF range of approximately 8°. Level of evidencelevel III

DIFFERENCES IN KNEE JOINT KINEMATICS AND KINETICS DURING LEVEL WALKING AND WALKING WITH TWO TYPES OF POLES — FOCUS ON KNEE VARUS MOMENT

Walking with poles is one of the gait modification strategies for reducing external knee varus moments in people with medial knee osteoarthritis (OA). However, there are two types of pole techniques, Nordic walking (NW: pole back condition) and pole walking (PW: pole front condition). The purpose of this study was to investigate the differences in knee joint kinematics, and kinetics during level walking, and two types of walking with poles. A total of 22 subjects with a mean age of 21.2 years (SD: 1.3 years) participated. Three-dimensional gait analysis was conducted on level walking (LW), NW and PW. The first and second peaks of the knee kinematic and kinetic data and ground reaction forces were used. No significant differences were found between NW and PW in the knee kinematics and kinetics data. The second peak of the knee varus moment in NW and PW (0.34 and 0.33 Nm/kg, respectively) was significantly decreased compared to LW (0.42 Nm/kg, p &lt; 0.01; Effect size = 0.70, p &lt; 0.01; Effect size = 0.82). The first peak of the flexion moment in the knee during NW (1.2 Nm/kg) was significantly higher compared to LW (1.2 Nm/kg, p &lt; 0.01; Effect size = 0.98). However, the present study could not clarify any different effect on the knee joint due to different instructions of the back pole and forward pole technique.

Hamstrings Stiffness and Landing Biomechanics Linked to Anterior Cruciate Ligament Loading

Greater hamstrings stiffness is associated with less anterior tibial translation during controlled perturbations. However, it is unclear how hamstrings stiffness influences anterior cruciate ligament (ACL) loading mechanisms during dynamic tasks. To evaluate the influence of hamstrings stiffness on landing biomechanics related to ACL injury. Cross-sectional study. Research laboratory. A total of 36 healthy, physically active volunteers (18 men, 18 women; age = 23 ± 3 years, height = 1.8 ± 0.1 m, mass = 73.1 ± 16.6 kg). Hamstrings stiffness was quantified via the damped oscillatory technique. Three-dimensional lower extremity kinematics and kinetics were captured during a double-legged jump-landing task via a 3-dimensional motion-capture system interfaced with a force plate. Landing biomechanics were compared between groups displaying high and low hamstrings stiffness via independent-samples t tests. Hamstrings stiffness was normalized to body mass (N/m·kg(-1)). Peak knee-flexion and -valgus angles, vertical and posterior ground reaction forces, anterior tibial shear force, internal knee-extension and -varus moments, and knee-flexion angles at the instants of each peak kinetic variable were identified during the landing task. Forces were normalized to body weight, whereas moments were normalized to the product of weight and height. Internal knee-varus moment was 3.6 times smaller in the high-stiffness group (t22 = 2.221, P = .02). A trend in the data also indicated that peak anterior tibial shear force was 1.1 times smaller in the high-stiffness group (t22 = 1.537, P = .07). The high-stiffness group also demonstrated greater knee flexion at the instants of peak anterior tibial shear force and internal knee-extension and -varus moments (t22 range = 1.729-2.224, P < .05). Greater hamstrings stiffness was associated with landing biomechanics consistent with less ACL loading and injury risk. Musculotendinous stiffness is a modifiable characteristic; thus exercises that enhance hamstrings stiffness may be important additions to ACL injury-prevention programs.

Lower Extremity Energy Absorption and Biomechanics During Landing, Part I: Sagittal-Plane Energy Absorption Analyses

Eccentric muscle actions of the lower extremity absorb kinetic energy during landing. Greater total sagittal-plane energy absorption (EA) during the initial impact phase (INI) of landing has been associated with landing biomechanics considered high risk for anterior cruciate ligament (ACL) injury. We do not know whether groups with different INI EA magnitudes exhibit meaningful differences in ACL-related landing biomechanics and whether INI EA might be useful to identify ACL injury-risk potential. To compare biomechanical factors associated with noncontact ACL injury among sagittal-plane INI EA groups and to determine whether an association exists between sex and sagittal-plane INI EA group assignment to evaluate the face validity of using sagittal-plane INI EA to identify ACL injury risk. Descriptive laboratory study. Research laboratory. A total of 82 (41 men, 41 women; age = 21.0 ± 2.4 years, height = 1.74 ± 0.10 m, mass = 70.3 ± 16.1 kg) healthy, physically active individuals volunteered. We assessed landing biomechanics using an electromagnetic motion-capture system and force plate during a double-legged jump-landing task. Total INI EA was used to group participants into high, moderate, and low tertiles. Sagittal- and frontal-plane knee kinematics; peak vertical and posterior ground reaction forces (GRFs); anterior tibial shear force; and internal hip extension, knee extension, and knee varus moments were identified and compared across groups using 1-way analyses of variance. We used a χ (2) analysis to compare male and female representation in the high and low groups. The high group exhibited greater knee-extension moment and posterior GRFs than both the moderate (P < .05) and low (P < .05) groups and greater anterior tibial shear force than the low group (P < .05). No other group differences were noted. Women were not represented more than men in the high group (χ(2) = 1.20, P = .27). Greater sagittal-plane INI EA likely indicates greater ACL loading, but it does not appear to influence frontal-plane biomechanics related to ACL injury. Women were not more likely than men to demonstrate greater INI EA, suggesting that quantification of sagittal-plane INI EA alone is not sufficient to infer ACL injury-risk potential.

Lower Extremity Energy Absorption and Biomechanics During Landing, Part II: Frontal-Plane Energy Analyses and Interplanar Relationships

Greater sagittal-plane energy absorption (EA) during the initial impact phase (INI) of landing is consistent with sagittal-plane biomechanics that likely increase anterior cruciate ligament (ACL) loading, but it does not appear to influence frontal-plane biomechanics. We do not know whether frontal-plane INI EA is related to high-risk frontal-plane biomechanics. To compare biomechanics among INI EA groups, determine if women are represented more in the high group, and evaluate interplanar INI EA relationships. Descriptive laboratory study. Research laboratory. Participants included 82 (41 men, 41 women; age = 21.0 ± 2.4 years, height = 1.74 ± 0.10 m, mass = 70.3 ± 16.1 kg) healthy, physically active volunteers. We assessed landing biomechanics with an electromagnetic motion-capture system and force plate. We calculated frontal- and sagittal-plane total, hip, knee, and ankle INI EA. Total frontal-plane INI EA was used to create high, moderate, and low tertiles. Frontal-plane knee and hip kinematics, peak vertical and posterior ground reaction forces, and peak internal knee-varus moment (pKVM) were identified and compared across groups using 1-way analyses of variance. We used a χ (2) analysis to evaluate male and female allocation to INI EA groups. We used simple, bivariate Pearson product moment correlations to assess interplanar INI EA relationships. The high-INI EA group exhibited greater knee valgus at ground contact, hip adduction at pKVM, and peak hip adduction than the low-INI EA group (P < .05) and greater peak knee valgus, pKVM, and knee valgus at pKVM than the moderate- (P < .05) and low- (P < .05) INI EA groups. Women were more likely than men to be in the high-INI EA group (χ(2) = 4.909, P = .03). Sagittal-plane knee and frontal-plane hip INI EA (r = 0.301, P = .006) and sagittal-plane and frontal-plane ankle INI EA were associated (r = 0.224, P = .04). No other interplanar INI EA relationships were found (P > .05). Greater frontal-plane INI EA was associated with less favorable frontal-plane biomechanics that likely result in greater ACL loading. Women were more likely than men to use greater frontal-plane INI EA. The magnitudes of sagittal- and frontal-plane INI EA were largely independent.

Trunk and Hip Biomechanics Influence Anterior Cruciate Loading Mechanisms in Physically Active Participants

Background: Excessive trunk motion and deficits in neuromuscular control (NMC) of the lumbopelvic hip complex are risk factors for anterior cruciate ligament (ACL) injury. However, the relationship between trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads during a sidestep cutting task has not been examined. Purpose: To determine if there is an association between multiplanar trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads with ACL injury during a sidestep cutting task. Study Design: Descriptive laboratory study. Methods: The hip and knee biomechanics and trunk motion of 30 participants (15 male, 15 female) were analyzed during a sidestep cutting task using an optoelectric camera system interfaced to a force plate. Trunk and lower extremity biomechanics were calculated from the kinematic and ground-reaction force data during the first 50% of the stance time during the cutting task. Pearson product moment correlation coefficients were calculated between trunk and lower extremity biomechanics. Multiple linear regression analyses were carried out to determine the amount of variance in triplanar knee loading explained by trunk motion and hip moments. Results: A greater internal knee varus moment (mean, 0.11 ± 0.12 N·m/kg*m) was associated with less transverse-plane trunk rotation away from the stance limb (mean, 20.25° ± 4.42°; r = −0.46, P = .011) and a greater internal hip adduction moment (mean, 0.33 ± 0.25 N·m/kg*m; r = 0.83, P < .05). A greater internal knee external rotation moment (mean, 0.11 ± 0.08 N·m/kg*m) was associated with a greater forward trunk flexion (mean, 7.62° ± 5.28°; r = 0.42, P = .020) and a greater hip internal rotation moment (mean, 0.15 ± 0.16 N·m/kg*m; r = 0.59, P = .001). Trunk rotation and hip adduction moment explained 81% (P < .05) of the variance in knee varus moment. Trunk flexion and hip internal rotation moment explained 48% (P < .05) of the variance in knee external rotation moment. Conclusion: Limited trunk rotation displacement toward the new direction of travel and hip adduction moment are associated with an increased internal knee varus moment, while a combined increase in trunk flexion displacement and hip internal rotation moment is associated with a higher internal knee external rotation moment. Clinical Relevance: Prevention interventions for ACL injury should encourage trunk rotation toward the new direction of travel and limit excessive trunk flexion while adjusting frontal- and transverse-plane hip NMC.

Hamstrings Stiffness and Landing Biomechanics Linked to Anterior Cruciate Ligament Loading.

Greater hamstrings stiffness is associated with less anterior tibial translation during controlled perturbations. However, it is unclear how hamstrings stiffness influences anterior cruciate ligament (ACL) loading mechanisms during dynamic tasks. To evaluate the influence of hamstrings stiffness on landing biomechanics related to ACL injury. Cross-sectional study. Research laboratory. A total of 36 healthy, physically active volunteers (18 men, 18 women; age = 23 ± 3 years, height = 1.8 ± 0.1 m, mass = 73.1 ± 16.6 kg). Hamstrings stiffness was quantified via the damped oscillatory technique. Three-dimensional lower extremity kinematics and kinetics were captured during a double-legged jump-landing task via a 3-dimensional motion-capture system interfaced with a force plate. Landing biomechanics were compared between groups displaying high and low hamstrings stiffness via independent-samples t tests. Hamstrings stiffness was normalized to body mass (N/m·kg-1). Peak knee-flexion and -valgus angles, vertical and posterior ground reaction forces, anterior tibial shear force, internal knee-extension and -varus moments, and knee-flexion angles at the instants of each peak kinetic variable were identified during the landing task. Forces were normalized to body weight, whereas moments were normalized to the product of weight and height. Internal knee-varus moment was 3.6 times smaller in the high-stiffness group (t22 = 2.221, P = .02). A trend in the data also indicated that peak anterior tibial shear force was 1.1 times smaller in the high-stiffness group (t22 = 1.537, P = .07). The high-stiffness group also demonstrated greater knee flexion at the instants of peak anterior tibial shear force and internal knee-extension and -varus moments (t22 range = 1.729-2.224, P < .05). Greater hamstrings stiffness was associated with landing biomechanics consistent with less ACL loading and injury risk. Musculotendinous stiffness is a modifiable characteristic; thus exercises that enhance hamstrings stiffness may be important additions to ACL injury-prevention programs.

Gait pattern and lower extremity alignment in children with Morquio syndrome

The gait in children with Morquio syndrome (MPS IV) has not been previously described. We reviewed the charts, gait analysis reports, and radiographs of nine children with no previous lower extremity surgery. Children with MPS IV had a slower walking speed, reduced cadence, and reduced stride length as compared with normal (P<0.05). There was increased knee flexion, genu valgus, and external tibial torsion during stance (P<0.05). Kinetics showed that knee varus moment was increased (P<0.05). There was a strong correlation between genu valgus measured on gait analysis and standing radiographs (r=0.89).

The Effects of an Unloading Knee Brace and Insole with Subtalar Strapping for Medial Osteoarthritis of the Knee

Objectives: We evaluated whether a valgus knee brace and an insole with subtalar strapping could reduce pain and improve functional scores over 12 months in patients with medial knee osteoarthritis (OA). Methods: OA was confirmed by radiography in all patients, who were divided into three groups: exercise (n = 44), insole (n = 55), and brace (n = 19). Clinical knee functions and gait analyses were evaluated. Results: After 12 months, the clinical results for all groups had improved compared to pretreatment findings. Although the knee varus moment decreased and the gait speed increased when the insole was worn initially, the effects of the insole decreased at 6 and 12 months. In contrast, the knee varus moment decreased and the gait speed increased when the brace was initially fitted. The effects of the brace were maintained during the 12 months. Conclusions: The insole was effective for patients with Kellgren-Lawrence Grades II and III, and the knee brace was effective for patients with Grades III and IV conditions. Furthermore, the knee brace was more effective when worn for more than 6 months, while the effects of the insoles were not continuous.

Associations between Hormonal and Mechanical Factors of Knee Osteoarthritis in Women—A Preliminary Study

The purpose of this study was to determine the associations between urinary estradiol (E2) metabolite concentration and medial knee loading with radiographic disease severity in middle aged women with initial stage knee osteoarthritis (OA). Women presenting with knee pain were recruited into a cross-sectional correlation study (KOA, n = 9, age = 52 ± 4 yrs). Self report menstrual history, the Modified Baecke Questionnaire and the Knee Injury and Osteoarthritis Outcome Score (KOOS) subjective data were collected. A fasting blood sample (follicle stimulating hormone (FSH) and Tumor Necrosis Factor-α (TNF-α)), and urine catch (16α-hydroxyestrone and 2-hydroxyestrone) were collected. Gait analysis using an 8-camera motion analysis system assessed internal knee varus moment and foot progression angle. Pearson Product moments tested for associations between urinary 16α-hydroxyestrone and 2-hydroxyestrone, TNF-α, medial knee loading, and radiographic disease severity (Kellgren/Lawrence (K/L) radiographic score). Significant correlations were found within the hormonal biomarkers (r = 0.94, p p p = 0.31). No correlations were found for radiographic disease severity or TNF-α. The lack of association between hormonal and biomechanical variables could be due to large variability of the E2 metabolites seen in the menopause transition and the limited structural changes of initial staged knee OA.

Detecting and quantifying global instability during a dynamic task using kinetic and kinematic gait parameters

ObjectivesInstability during gait can be identified in many different ways. Recent studies have suggested utilizing spatiotemporal parameters to detect instability during gait. Detecting instability using kinetic and kinematic gait parameters has not yet been examined fully. In addition, these studies have not yet identified measures that are capable of assessing the magnitude of instability. The objective of the present study was to identify kinetic and kinematic gait parameters that can best identify instability and quantify its magnitude. MethodsTen healthy men underwent successive gait analysis testing under three controlled settings: (1) Stage 0 instability (control setting), (2) Stage 1 instability and (3) Stage 2 instability. The levels of instability were precisely applied with the use of a controlled perturbation device (AposTherapy System). Differences between all stages and between stages were identified using Friedman and Wilcoxon tests. ResultsStride-to-stride variability (STSV) in kinetic and kinematic measures increased significantly between stages 0 and 1 or between stages 0 and 2 for almost all parameters (all P<0.05). A significant increase between stage 0 and both stages 1 and 2 was found for knee flexion moment, knee varus moment, knee flexion angle and hip adduction angle. The increase between stages 1 and 2 was variable. Only the knee varus moment parameter showed a significant increase in STSV between stages 1 and 2 (P=0.026). ConclusionsAlmost all kinetic and kinematic gait parameters are sensitive to changes in global instability in a dynamic task. The most sensitive are parameters measured at the knee. Of these, STSV in knee varus moment can be used to quantify the magnitude of dynamic instability.

What Strains the Anterior Cruciate Ligament During a Pivot Landing?

Background: The relative contributions of an axial tibial torque and frontal plane moment to anterior cruciate ligament (ACL) strain during pivot landings are unknown. Hypothesis: The peak normalized relative strain in the anteromedial (AM) bundle of the ACL is affected by the direction of the axial tibial torque but not by the direction of the frontal plane moment applied concurrently during a simulated jump landing. Study Design: Controlled and descriptive laboratory studies. Methods: Fifteen adult male knees with pretensioned knee muscle-tendon unit forces were loaded under a simulated pivot landing test. Compression, flexion moment, internal or external tibial torque, and knee varus or valgus moment were simultaneously applied to the distal tibia while recording the 3D knee loads and tibiofemoral kinematics. The AM-ACL relative strain was measured using a 3-mm differential variable reluctance transducer. The results were analyzed using nonparametric Wilcoxon signed–rank tests. A 3D dynamic biomechanical knee model was developed using ADAMS and validated to help interpret the experimental results. Results: The mean (SD) peak AM-ACL relative strain was 192% greater (P < .001) under the internal tibial torque combined with a knee varus or valgus moment (7.0% [3.9%] and 7.0% [4.1%], respectively) than under external tibial torque with the same moments (2.4% [2.5%] and 2.4% [3.2%], respectively). The knee valgus moment augmented the AM-ACL strain due to the slope of the tibial plateau inducing mechanical coupling (ie, internal tibial rotation and knee valgus moment); this augmentation occurred before medial knee joint space opening. Conclusion: An internal tibial torque combined with a knee valgus moment is the worst-case ACL loading condition. However, it is the internal tibial torque that primarily causes large ACL strain. Clinical Relevance: Limiting the maximum coefficient of friction between the shoe and playing surface should limit the peak internal tibial torque that can be applied to the knee during jump landings, thereby reducing peak ACL strain and the risk for noncontact injury.

Motion of the rearfoot, ankle and subtalar joints and ankle moments when wearing lateral wedge insoles – results from bone anchored markers

Background Knee osteoarthritis is a debilitating condition and increased dynamic loading at the knee has been linked with increased progression of the disease. Lateral wedge insoles have been used in clinical practice since the late 1980s. It is theorised that lateral wedge insoles increase the subtalar joint valgus orientation and increase the ankle valgus moment [1], with subsequent reduced knee varus moments [2]. Results have shown that both clinical success and reductions in knee loading vary between people. Differences could be due to person specific foot biomechanics. The aim of this study was to determine the changes in frontal plane foot and ankle motion and moment due to a lateral wedge orthosis.

착지의 높이와 거리가 무릎 부상 메카니즘에 미치는 영향

Various jumping and landing motions are shown during sports event. But most previous studies have not considered landing height and distance simultaneously. The purpose of this study was to identify the effects of landing height and distance on knee injury mechanism. Fourteen male(age: <TEX>$28.86{\pm}1.99$</TEX> yrs, height: <TEX>$177.00{\pm}4.69$</TEX> cm, weight: <TEX>$76.50{\pm}6.41$</TEX> kg) participated in this study. The subjects attempted drop landing task onto the ground from 30 cm to 45 cm heights and to 20 cm to 40 cm distances. The results were as follows. First, higher drop landing height and longer distance showed greater degree of maximal knee flexion and valgus. Second, higher drop landing height and longer distance showed greater maximal knee extension moment and varus moment. Third, higher drop landing height and longer distance showed larger maximal knee absorption power. Lastly, higher drop landing height showed increased Peak GRF. Landing height was more related to the cause of injury, which was indicated by increased maximal knee extension moment, peak GRF and maximal knee absorption power. Landing distance was also associated with increased knee valgus moment and absorption power during landing. These results suggest that landing height and distance may be the cause of injury.