Knee Varus Angle Research Articles

A-11 キャンバー角が走動作に及ぼす影響(走動作)

Recently, trail running on various surface conditions, i.e. uphill, downhill, wet, rock and so on, is getting popular year by year. In these surface conditions, it is predicted that load applied to the lower-extremity becomes higher during running on camber, which demonstrates the condition to run across sloped surface laterally. However, there are few studies that have discussed relationship between footwear stability and kinematics of lower-extremity in camber running. The purpose of this kinematics in camber running, motion analyses on three surface conditions (flat, CM: Medial side of the foot gets higher than lateral and CL: Lateral side of the foot gets higher than medial) were carried out. As a result, rearfoot eversion angle (β) in CL running and knee varus angle (ζ) in CM running become higher than those in flat running at foot flat phase. It was also confirmed that knee varus angle has a high correlation with rearfoot inversion angle in CM running. Furthermore, the influence of sole structures on β and ζ was also discussed.

Observation of the effect of TKA in the treatment of knee osteoarthritis patients with varus deformity

Objective To explore the clinical effect of aritificial total knee arthroplasty （ TKA） in the treat-ment of knee osteoarthritis （ KOA） patients with varus deformity .Methods 41 KOA patients （ 52 knees ） with varus deformity were treated by TKA ,and the clinical effect was observed .Results After treatment ,the knee varus angle , flexion contracture degrees,HSS score were （174.50 ±2.10）°,（0.30 ±0.16）°,（87.60 ±4.70）points,respective-ly,which were significantly improved compared with [（19.80 ±1.30）°,（21.20 ±0.90）°,（37.30 ±3.50）points] before treatment （t=451.68,165.99,69.05,51.57,all P〈0.05）.Conclusion TKA has an ideal efficacy for knee flexion deformity ,accurately cut bone and soft tissue balance correction is the key in turned knee flexion contracture deformity surgery . Key words: Osteoarthritis; knee; Knee prosthesis; aritificial

Varus thrust and knee frontal plane dynamic motion in persons with knee osteoarthritis

Varus thrust visualized during walking is associated with a greater medial knee load and an increased risk of medial knee osteoarthritis (OA) progression. Little is known about how varus thrust presence determined by visual observation relates to quantitative gait kinematic data. We hypothesized that varus thrust presence is associated with greater knee frontal plane dynamic movement during the stance phase of gait. Participants had knee OA in at least one knee. Trained examiners assessed participants for varus thrust presence during ambulation. Frontal plane knee motion during ambulation was captured using external passive reflective markers and an 8-camera motion analysis system. To examine the cross-sectional relationship between varus thrust and frontal plane knee motion, we used multivariable regression models with the quantitative motion measures as dependent variables and varus thrust (present/absent) as predictor; models were adjusted for age, gender, body mass index (BMI), gait speed, and knee static alignment. 236 persons [mean BMI: 28.5kg/m(2) (standard deviation (SD) 5.5), mean age: 64.9 years (SD 10.4), 75.8% women] contributing 440 knees comprised the study sample. 82 knees (18.6%) had definite varus thrust. Knees with varus thrust had greater peak varus angle and greater peak varus angular velocity during stance than knees without varus thrust (mean differences 0.90° and 6.65°/s, respectively). These patterns remained significant after adjusting for age, gender, BMI, gait speed, and knee static alignment. Visualized varus thrust during walking was associated with a greater peak knee varus angular velocity and a greater peak knee varus angle during stance phase of gait.

Causal link between peak knee adduction moment during walking and structural progression of knee osteoarthritis: a systematic review of cohorts and randomized trials

treatment for end-stage knee OA, with approximately 500,000 procedures performed each year in the United States. Several studies have examined the long-term effects of TKA on the biomechanics of the operated knee and have found that most patient still demonstrate poor gait patterns that are similar to their gait patterns preoperatively. In the frontal plane, researchers have found that KAM is improved at 6 months after surgery, but slowly regresses back to higher, preoperative levels after 1 year. In the long-term, KAM is not significantly different from preoperative levels. This finding is noteworthy since high KAM may result in prosthetic degradation and failure in the long term. There is a lack of information on the biomechanical postoperative results of surgery in the period earlier than six months. The purpose of the present study was to determine if gait patterns of the knee in the frontal plane are improved in the early postoperative period. This would help determine what, if any, changes can be made to therapy protocols to prevent regression to preoperative gait levels with time. Furthermore, outcomes were examined across different knee prosthetics to determine if differences exist between prosthetic types. Methods: Fifty patients were examined before and two months after TKA. Patients underwent a 3D gait analysis using the Vicon Motion Analysis system (Oxford Metrics Ltd., Oxford, UK). Patients completed a VAS scale for pain and functional tests. Knee prosthetics included either PCL-retaining or PCL sacrificing, and custom fit design or not. Results: Peak knee varus angle during gait showed a significant reduction and improvement of 3.1 postoperatively (p1⁄40.001) (Figure 1). After surgery, first and second peak KAM decreased to 71% and 77% of preoperative values (Figure 2), respectively (both p1⁄40.001), and knee adduction impulse decreased by 30% postoperatively (p<0.001) (Table 1) and VAS pain scores decreased by 21% (p<0.001). Spatiotemporal parameters and functional tests did not yet show significant improvements by two months. No significant differences were found between outcomes in patients undergoing PCL retaining TKA or PCL sacrificing TKA, or between patients undergoing custom fit TKA and those not. Changes were consistent across BMI, age, gender and pain scores. Conclusions: TKA results in high improvement in kinematic and kinetic parameters in the frontal plane early in postoperative recovery. The results also suggest that there is an absence of differences between types of knee prostheses. When compared to the findings of previous studies, the results suggest that early after surgery, TKA patients will show decreased, improved KAM, but these improvements are slowly lost over the first and second year postoperatively. This highlights the importance of early intervention postoperatively aimed at maintaining the low levels of KAM and joint loading. This may help reduce the risk of prosthetic failure and surgical revision in the long-term. 146 CAUSAL LINK BETWEEN PEAK KNEE ADDUCTION MOMENT DURING WALKING AND STRUCTURAL PROGRESSION OF KNEE OSTEOARTHRITIS: A SYSTEMATIC REVIEW OF COHORTS AND RANDOMIZED TRIALS M. Henriksen , M. Creaby , H. Lund , C. Juhl , R. Christensen . y The Parker Inst., Copenhagen, Denmark; Ctr. of Physical Activity Across the Lifespan, Sch. of Exercise Sci., Australian Catholic Univ., Brisbane, Australia; x Inst. of Sports Sci. and Clinical Biomechanics, Univ. of Southern Denmark, Odense, Denmark

A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

Does Total Knee Arthroplasty Change Frontal Plane Knee Biomechanics During Gait?

Dynamic knee varus angle and adduction moments have been reported to be reduced after TKA. However, it is unclear whether this reduction is maintained long term. We therefore asked whether (1) the dynamic knee adduction angle and moment remain reduced 1 year after TKA, (2) if changes in adduction moment are related to static alignment and varus angle during gait 6 months and 1 year after TKA, and (3) if these changes in loading pattern are related to changes in Knee Society scores. We performed gait analysis on 15 patients (17 TKAs) before surgery and 6 months and 1 year after TKA. Weightbearing radiographs were used to assess coronal plane knee alignment. TKA corrected static knee alignment from 2.2° (2.5°) varus to 3.5° (2.7°) valgus at 6 months. Peak varus angle during gait was reduced from 9.7° (6.5°) to 3.6° (5.8°) at 6 months and 5.2° (7.6°) at 1 year. Peak adduction moment was reduced to 85% of the preoperative level at 6 months but increased to 94% of the preoperative level at 1 year. We observed a correlation between the increase in dynamic varus angle and increase in adduction moment from the 6-month to 1-year followups. TKA improves knee adduction moment at 6 months, but this effect is lost with time (1 year). Despite restoration of static knee alignment, knee adduction moment remains high presumably predisposing to medial polyethylene wear as noted by retrieval studies.

The effect of total knee replacement on the knee varus angle and moment during walking and stair ascent

Background This study examined the effect of total knee replacement surgery on the frontal plane knee varus angle and moment. Secondarily, the relationships between knee varus angle and moment to a clinical outcome measure were assessed. Methods Twenty-one patients with total knee replacement and 21 controls performed level walking and stair ascent at two testing periods, pre- and 6-months post-surgery. The dependent variables included frontal plane knee angle and moment, and Western Ontario and McMaster Universities Osteoarthritis Index scores. Findings During level walking the mean knee varus moment of the patient group was significantly greater than controls at pre-surgery but was restored to control level post-operatively. During stair ascent the patient group produced a significantly smaller knee varus moment post-surgically. The mean frontal knee valgus angle of total knee replacement patients increased significantly from pre- to post-surgery during level walking. The Western Ontario and McMaster Universities Osteoarthritis Index score was not significantly correlated to the knee variables. However, the knee angle and moment were significantly correlated during level walking pre- and post-operatively and stair ascent post-operatively. Interpretation The decreased frontal plane knee moment in total knee replacement patients during level walking appeared to be affected by surgical realignment of the tibio–femoral joint, as the frontal knee angle and varus moment were strongly correlated. The subjective Western Ontario and McMaster Universities Osteoarthritis Index and the objective gait measures appeared to capture different dimensions of knee osteoarthritis.

Gender Differences in Lower Extremity Landing Mechanics Caused by Neuromuscular Fatigue

Background Neuromuscular fatigue has been suggested as an extrinsic factor in the mechanism of noncontact anterior cruciate ligament injury in both genders. Purpose To determine and describe the lower extremity kinematic and kinetic differences caused by neuromuscular fatigue during drop landings and compare changes between age- and skill-matched male and female athletes. Methods Inverse dynamic solutions estimated lower extremity flexion-extension and varus-valgus kinematics and kinetics for 14 female and 16 male athletes performing a single-legged 50-cm drop landing. Subjects performed landings prefatigue and postfatigue with fatigue induced via a parallel squat exercise (60% of 1 repetition maximum) until failure. A mixed-model, repeated-measures analysis of variance (fatigue * gender) was performed on select kinematic and kinetic variables. Results Neuromuscular fatigue caused men and women to land with more hip flexion (main effect fatigue, P = .012; main effect gender, P = .001). Men exhibited greater peak knee flexion angles postfatigue; women did not alter knee flexion (fatigue * gender, P =.028). Men exhibited larger peak knee varus angles irrespective of fatigue (main effect gender, P = .039; main effect fatigue, P = .127; fatigue * gender, P = .153); women demonstrated larger peak valgus angles overall (main effects gender, P = .009). There were no changes with fatigue (main effect fatigue, P = .127) or a different response due to fatigue with gender (fatigue * gender, P = .091). Women exhibited greater knee anterior shear force postfatigue (fatigue * gender, P = .010). Men and women exhibited lower knee extension moments (main effect fatigue, P = .000; main effect gender, P = .927; fatigue * gender, P = .309) and abduction moments (main effect fatigue, P = .014; main effect gender, P = .670; fatigue * gender, P = .191). Conclusion Neuromuscular fatigue caused significant alterations in women that may be indicative of the noncontact anterior cruciate ligament injury mechanisms. Clinical Relevance Current noncontact anterior cruciate ligament prevention programs should incorporate a fatigue component to help minimize the deleterious effects of neuromuscular fatigue on landing mechanics.

Effects of Gender and Foot-Landing Techniques on Lower Extremity Kinematics during Drop-Jump Landings

The purpose of this study was to assess kinematic lower extremity motion patterns (hip flexion, knee flexion, knee valgus, and ankle dorsiflexion) during various foot-landing techniques (self-preferred, forefoot, and rear foot) between genders. 3-D kinematics were collected on 50 (25 male and 25 female) college-age recreational athletes selected from a sample of convenience. Separate repeated-measures ANOVAs were used to analyze each variable at three time instants (initial contact, peak vertical ground reaction force, and maximum knee flexion angle). There were no significant differences found between genders at the three instants for each variable. At initial contact, the forefoot technique (35.79 degrees +/- 11.78 degrees ) resulted in significantly (p = .001) less hip flexion than did the self-preferred (41.25 degrees +/- 12.89 degrees ) and rear foot (43.15 degrees +/- 11.77 degrees ) techniques. At peak vertical ground reaction force, the rear foot technique (26.77 degrees +/- 9.49 degrees ) presented significantly lower (p = .001) knee flexion angles as compared with forefoot (58.77 degrees +/- 20.00 degrees ) and self-preferred (54.21 degrees +/- 23.78 degrees ) techniques. A significant difference for knee valgus angles (p = .001) was also found between landing techniques at peak vertical ground reaction force. The self-preferred (4.12 degrees +/- 7.51 degrees ) and forefoot (4.97 degrees +/- 7.90 degrees ) techniques presented greater knee varus angles as compared with the rear foot technique (0.08 degrees +/- 6.52 degrees ). The rear foot technique created more ankle dorsiflexion and less knee flexion than did the other techniques. The lack of gender differences can mean that lower extremity injuries (e.g., ACL tears) may not be related solely to gender but may instead be associated with the landing technique used and, consequently, the way each individual absorbs jump-landing energy.

Relationship between hip strength and frontal plane posture of the knee during a forward lunge

Objective:Excessive frontal plane knee movement during forward lunge movements might be associated with the occurrence of knee injuries in tennis. Here, we attempt to determine whether hip muscle strength is...

Muscle strength in knee varus and valgus

The purpose of this study was to investigate the lower-limb muscle strength in knee varus-valgus and its dependence on knee varus-valgus position. The hypothesis was that humans could differentially contract the medial and lateral muscles crossing the knee and generate significant moments in knee valgus-varus. The subjects sat with the knee at full extension and secured from the medial, lateral, anterior, and posterior sides. Both hips were clamped from the lateral sides. The subjects adducted (abducted) the ipsilateral hip during the knee valgus (varus) maximal voluntary contraction with EMG signals recorded from muscles crossing the knee and knee joint moments measured using a six-axis force sensor. Frontal plane tibiofemoral movement was evaluated using a fluoroscope. The subjects differentially contracted the medial and lateral muscles, and fluoroscope images showed the corresponding tibiofemoral movement. The subjects showed considerable strength in knee varus and valgus. The active knee varus strength increased significantly with increasing knee valgus angle, and the valgus strength was significantly higher when the knee was in varus position (P < 0.039). Active valgus muscle strength at 5 degrees knee varus was significantly higher than the active varus strength at 5 degrees valgus (P = 0.002). The passive resistance moment increased linearly with increasing knee valgus and varus angles, and it accounted for 28% and 35% of the total (active plus passive) moment at the 5 degrees varus and 5 degrees valgus, respectively. The significant varus-valgus muscle strength demonstrated in this study may play important roles in performing various functional tasks, maintaining joint stability, and preventing potential injuries, whether the major load and motion at the knee is in the frontal plane or not.

Valgus-varus motion of the knee in normal level walking and stair climbing

Objective. The knee valgus-varus moment and the knee angles were compared between normal level walking and stair climbing. Design. Ten healthy subjects were tested for ascent, descent, and level walking. Background. An understanding of the normal valgus-varus motion of the knee during stair climbing is needed to apply biomechanical analysis of stair climbing as a evaluation tool for knee osteoarthritis patients. Methods. A motion analysis system, three force plates, and a flight of stairs were used to collect kinematic and kinetic data. The knee angles and moments were calculated from the collected kinematic and kinetic data. Results. The knee varus angle for the maximum knee valgus moments in stair climbing was significantly greater than that in level walking. The knee valgus moment was significantly correlated to ground reaction forces and knee valgus-varus angle during stair climbing and level walking. Conclusions. There is a coupling between the knee valgus-varus motion and flexion-extension motion. Ground reaction forces are the major contributors to the within-subject variation in the knee valgus-varus moment during stair climbing and level walking. The knee valgus-varus angle is a major contributor to the between-subject variation in the knee valgus moment during stair climbing and level walking.