Knee Varus Angle Research Articles

Tibial Torsion and Knee Varus Angle: Are These Aetiologies of Hallux Valgus?

Objective The purpose of this study is to evaluate that knee deformity (varus or valgus) due to osteoarthritis of the knee and tibial torsion could be aetiologies of hallux valgus. Methods Forty-nine patients (43 females, six males; mean patient age, 69.88 ± 6.12 years) before total knee arthroplasty for advanced primary osteoarthritis were recruited. All deformities were of the left knee. Preoperative torsional computed tomography, anteroposterior (AP) and lateral weight-bearing foot radiographs, AP and lateral weight-bearing knee radiographs, and long-leg standing AP views were obtained for each patient. The correlations between foot angle and knee varus angle or tibial torsion angle were examined. Results There was no significant correlation between knee varus angle and foot angle. Similarly, there was no significant relationship between tibial torsional angle and foot angle, except talocalcaneal angle (TCA)-lateral (r=0.28). No significant relationships were found between TCA-AP and (1–2 intermetatarsal angle [IMA] and hallux valgus angle [HVA]), or between TCA-lateral and (1–2 IMA and HVA). Conclusion No significant correlations were found between the knee anatomical axis (knee varus angle) and foot angle or between the tibial torsional angle and foot angle. Tibial torsion and knee varus angle were not aetiologies for hallux valgus. Key words: Hallux valgus; Aetiologies; Tibial torsion; Varus knee angle

Effectiveness of double-plane high tibial osteotomy in treatment of medial compartment osteoarthritis

To investigate the effectiveness of double-plane high tibial osteotomy in treatment of medial compartment osteoarthritis. The clinical data of 65 patients with medial compartment osteoarthritis who were treated with double-plane high tibial osteotomy between January 2014 and January 2017 was retrospectively analyzed. There were 28 males and 37 females. The age ranged from 46 to 75 years with an average of 53.2 years. There were 30 cases in the left knee and 35 cases in the right knee. The disease duration was 3-7 years (mean, 4.0 years). The patients had different degrees of pain in the knee joint and difficulty walking. The knee joint compression test was positive. The knee joint function was evaluated by Hospital for Special Surgery (HSS) score and knee society score (KSS) clinical and functional scores. The visual analogue scale (VAS) score was adopted to pain measurement. The healing of osteotomy was observed by X-ray films during follow-up; the femur tibia angle (FTA), posterior tibial slope (PTS), medial proximal tibial angle (MPTA), and knee varus angle (KVA) were also calculated. All the incisions healed by first intention after operation. Only 1 case had numbness of the toe, and the symptoms disappeared after symptomatic treatment. All patients were followed up 13-18 months with an average of 15.4 months. X-ray examination showed that all patients had bone healing at 12 weeks after operation. There were significant differences in MPTA, FTA, PTS, and KVA between pre- and post-operation ( P<0.05). There was no significant difference in above parameters among 1 week, 6 months, and 12 months after operation ( P>0.05). There was no loosening and rupture of the fixator during the follow-up. The HSS score and KSS clinical and functional scores at 12 months after operation were significantly higher than those before operation ( P<0.05). The VAS scores at 1 week, 6 months, and 12 months after operation were significantly lower than that before operation ( P<0.05). Double-plane high tibial osteotomy for medial compartment osteoarthritis can effectively relieve pain symptoms and improve joint function.

Gait biomechanics in individuals with patellar tendon and hamstring tendon anterior cruciate ligament reconstruction grafts

Anterior cruciate ligament reconstruction (ACLR) restores joint stability following ACL injury but does not attenuate the heightened risk of developing knee osteoarthritis. Additionally, patellar tendon (PT) grafts incur a greater risk of osteoarthritis compared to hamstring grafts (HT). Aberrant gait biomechanics, including greater loading rates (i.e. impulsive loading), are linked to the development of knee osteoarthritis. However, the role of graft selection on walking gait biomechanics linked to osteoarthritis is poorly understood, thus the purpose of this study was to compare walking gait biomechanics between individuals with HT and PT grafts. Ninety-eight (74 PT; 24 HT) subjects with a history of ACLR performed walking gait at a self-selected speed from which the peak vertical ground reaction force (vGRF) during the first 50% of the stance phase and its instantaneous loading rate, peak internal knee extension and valgus moments, and peak knee flexion and varus angles were obtained. When controlling for time since ACLR and quadriceps strength, there were no differences in any kinetic or kinematic variables between graft types. While not significant, 44% of the PT cohort were identified as impulsive loaders (displaying a heelstrike transient in the majority of walking trials) compared to only 25% of the HT cohort (odds ratio = 2.3). This more frequent observation of impulsive loading may contribute to the greater risk of osteoarthritis with PT grafts. Future research is necessary to determine if impulsive loading and small magnitude differences between graft types contribute to osteoarthritis risk when extrapolated over thousands of steps per day.

Mid-flight lateral trunk bending increased ipsilateral leg loading during landing: a center of mass analysis

ABSTRACTIncreased lateral trunk bending to the injured side has been observed when ACL injuries occur. The purpose was to quantify the effect of mid-flight lateral trunk bending on center of mass (COM) positions and subsequent landing mechanics during a jump-landing task. Forty-one recreational athletes performed a jump-landing task with or without mid-flight lateral trunk bending. When the left and right trunk bending conditions were compared with the no trunk bending condition, participants moved the COM of the upper body to the bending direction, while the COM of the pelvis, ipsilateral leg, and contralateral leg moved away from the bending direction relative to the whole body COM. Participants demonstrated increased peak vertical ground reaction forces (VGRF) and knee valgus and internal rotation angles at peak VGRF for the ipsilateral leg, but decreased peak VGRF and knee internal rotation angles at peak VGRF and increased knee varus angles at peak VGRF for the contralateral leg. Mid-flight lateral trunk resulted in an asymmetric landing pattern associated with increased ACL loading for the ipsilateral leg. The findings may help to understand altered trunk motion during ACL injury events and the discrepancy in ACL injuries related to limb dominance in badminton and volleyball.

Dynamic Varus and the Development of Iliotibial Band Syndrome.

Although the risk of osteoarthritis development after acute knee injury has been widely studied, the long-term consequences of knee overuse injury are not well understood. To identify the relationship between gait-related risk factors associated with osteoarthritis and the development of iliotibial band syndrome (ITBS) in members of a single University Army Reserve Officers' Training Corps unit. Prospective cohort study. Biomechanics laboratory. Sixty-eight cadets undergoing standardized physical fitness training. Three-dimensional lower extremity kinematics (240 Hz) and kinetics (960 Hz) were collected for 3 bilateral trials during shod running at 4.0 m/s ± 10%. Injury tracking was conducted for 7 months of training. Biomechanical variables, including varus thrust and knee-adduction moment, were compared between the injured and control groups. Twenty-six cadets with no history of overuse injury served as the control group, whereas 6 cadets (7 limbs) who developed ITBS that required them to modify their training program or seek medical care (or both) served as the injured group. Maximum varus velocity was higher ( P = .006) and occurred sooner during stance ( P = .04) in the injured group than in the control group, indicating greater varus thrust. Maximum knee-varus angle and maximum knee-adduction moment were higher ( P = .02 and P = .002, respectively) and vertical stiffness was lower ( P = .03) in the injured group. Measures of dynamic varus stability appeared to be altered in individuals who developed ITBS. Biomechanical knee variables previously identified as increasing the risk for knee osteoarthritis were also associated with the development of ITBS in healthy adults.

Gait analysis in short-term follow-up of medial opening wedge high tibial osteotomy.

Biomechanical gait changes are proposed as adaptations to medial knee osteoarthritis (OA), and little is known about which parameters can be modified early by high tibial osteotomy (HTO) surgery. The aim of this study was to identify early gait changes in a postoperative period of 6months as compared to a control group, in three different spatial planes. Twenty-one patients with OA were submitted to three-dimensional gait analysis preoperatively and 6months after HTO surgery. Sixteen healthy individuals were selected for the control group. Compared to the control group, OA patients walked more slowly, with a shorter stride length, and with a higher knee varus and flexion angles. The gait changes detected in the postoperative of 6months were a significant reduction in knee varus angle and adductor moment in coronal plane; an important reduction in knee extension and an increased extensor moment in sagittal plane; also an increased foot external rotation angle in axial plane was observed. Flexion angle peak in swing phase, adductor and flexor moments were the gait parameters with postoperatively results that were closer to those of the control group. Even in a short follow-up of 6months, HTO determines positive results in biomechanical gait, not only in the coronal plane but also in the sagittal and axial planes and should be taken into account during the rehabilitation process.

Kinematic and kinetic gait deviations in males long after anterior cruciate ligament reconstruction

BackgroundBiomechanical deviations long (approx. 5years) after anterior cruciate ligament reconstruction have not been quantified in males, despite their distinct risk profile as compared to females. These deviations can indicate altered joint loading during chronic, repetitive motions. MethodsCross-sectional study, comparing kinematic and kinetic variables between 15 male anterior cruciate ligament reconstructed patients and 15 healthy controls. During walking and running gait, measurements were taken of impact dynamics, knee and hip sagittal plane angles and moments, and knee varus angles and adduction moments. FindingsComparing affected limbs to control limbs, significantly lower maximum (P=0.001) and initial (P=0.003) loading rates were found during running, but not in walking. Hip angles were lower for affected limbs of patients compared to the control group (P=0.039) in walking, but not during running. Between-limb comparisons showed important differences in symmetry of the affected patients. Maximum force during running was higher in the unaffected limb (P=0.015), which was linked with a higher loading rate (P=0.008). Knee flexion angle was reduced by 2° on average for the affected limb during running (P=0.010), and both walking and running knee and hip moments showed differences. Knee varus angle showed a 1° difference during walking (P<0.001), but not during running. Knee adduction moment was significantly lower (more valgus) during both walking and running. InterpretationMale anterior cruciate ligament reconstructed patients demonstrate persistent, clinically important gait asymmetries and differences from healthy controls long after surgery in kinematics, kinetics, and impact biomechanics.

Influence of increasing knee flexion angle on knee-ankle varus stress during single-leg jump landing.

ObjectivesThe primary aim of this study was to identify the relationship between the peak knee flexion angle and knee-ankle varus stress in the landing phase of the single-leg jump during running.MethodsFifteen male handball players from the first Saudi Arabian handball team were incorporated in this study. Each player performed a single-leg jump-land after running a fixed distance of 450 cm. The data were measured using a 3D motion analysis system. The maximum knee flexion angle, knee varus angle, centre of pressure pathway in the medio-lateral direction, and ankle varus moment were measured.ResultsThe Pearson Product Moment Correlation showed that a greater knee flexion angle was related to a greater lateral displacement of the centre of pressure (r = 0.794, P = 0.000), a greater ankle varus moment (r = 0.707, P = 0.003), and a greater knee varus angle (r = 0.753, P = 0.001). In addition, the greater ankle varus moment was related to the greater lateral displacement of the centre of pressure (r = 0.734, P = 0.002).ConclusionsThese findings may help physical therapists and conditioning professionals to understand the impact of increasing knee flexion angle on the lower limb joints. Such findings may help to develop training protocols for enhancing the lateral body reaction during the landing phase of the single-leg jump, which may protect the knee and ankle joints from excessive varus stresses.

Comparison between different osteotomy methods for kneeling ability recovery after total knee arthroplasty

Objective To compare the clinical outcomes between two different femur rotating osteotomy methods for kneeling ability recovery after total knee arthroplasty (TKA). Methods From January 2012 to December 2014, 88 patients under-went TKA were selected for a retrospective study and were divided into two groups based on the methods to determine femoral rota-tion. Forty-eight patients were in measured resection group, while 40 patients in gap balancing group. The patients in both groups underwent fixed-bearing tibia prosthesis. There were no statistical significance between the two groups in gender, age, BMI and knee varus angle (P>0.05). The knee varus angle, ROM, Oxford knee score (OKS) and American Knee Society (KSS) knee score were collected to assess malformation correction, kneeling ability and functions at pre-operation, one and two years postoperative-ly. Results The operation duration and blood loss in measured resection group were 80±19 min and 348±121 ml, while these da-ta in gap balancing group were 82±23 min and 315±100 ml respectively (P>0.05). Patients in measured resection group were fol-lowed up 24-59 months (mean 43±11 months), while the followed-up duration in gap balancing group was 25-58 months (mean 47±10 months). No major complications such as infection loosen and instability were occurred. Varus angles in measured resection group at postoperative 1 year and 2 year postoperative were 1.2°±0.4° and 1.0°±0.2° respectively, while those in gap balancing group were 0.9°±0.2° and 0.8°±0.3° (P>0.05). The scores of the seventh item of OKS in measured resection group at 1 year and 2 year follow-ups were 2.79±1.02 and 2.75±1.03 respectively, while those in the gap balancing group were 1.90±0.85 and 1.80±0.83 (P<0.01). ROM in the measured resection group at 1 year and 2 year postoperative were 102.08°±15.60° and 102.08°±15.60° re-spectively, while those in the gap balancing group were 112.50°±18.32° and 113.00°±18.09° (P<0.05). KSS in measured resection group at postoperative 1 year and 2 years were 154.63±31.12 and 154.63±31.26 respectively, while those in the gap balancing group were 170.55±22.67 and 173.45±22.52 (P<0.05). Conclusion The method of measured resection and gap balancing to con-firm femoral rotation during TKA can both achieve favorable kneeling ability and clinical outcomes, while gap balancing show su-periority on kneeling ability recovery, ROM and clinical outcomes at 2-year postoperative improvement. Key words: Arthroplasty, replacement, knee; Osteotomy; Range of motion, articular

CT およびMR 画像に基づく膝関節モデルを用いた膝内反角度変化に関する応力解析

CT およびMR 画像に基づく膝関節モデルを用いた膝内反角度変化に関する応力解析

Effects of Combined Wedge on Angle and Moment of Ankle and Knee Joint During Gait in Patients With Genu Varus

The purpose of this study was to investigate the effects of combined wedge on the range of motion in ankle and knee joint, ankle eversion moment and knee adduction moment, and center of pressure excursion of foot for genu varus among adult men during gait. This study was carried out with 10 adult men for genu varus in a motion analysis laboratory in J university. The subjects of the experiment were measured above 5cm width between the knees on contact of both medial malleolus of ankle while standing. The width of their knees in neutral position was measured without the inversion or eversion of the subtalar joint by the investigator. The subjects of the experiment were ten who were conducted randomly for standard insole, insole with 10° lateral on rear foot wedge, insole at 10°lateral on rear foot and 5° medial on fore foot wedge. Before and after intervention, changes on the range of motion in ankle and knee joint, ankle eversion moment and knee adduction moment, and center of pressure excursion were measured. In order to compare analyses among groups; repeated one-way ANOVA and Scheffe post hoc test were used. As a result, combined wedge group was significantly decreased compared to control wedge group in terms of knee varus angle in mid-stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge group in terms of ankle eversion moment in whole stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge group in terms of knee adduction moment in whole stance(p<.05). Combined wedge group was significantly decreased compared to lateral wedge in terms of center of pressure excursion in whole stance(p<.05). The results of this study suggest that combined wedge for genu varus decreased ankle eversion moment and knee adduction moment upon center of pressure excursion. We hypothesize that combined wedge may also be effective in the protection excessive ankle pronation.

Varus thrust in women with early medial knee osteoarthritis and its relation with the external knee adduction moment

Background: Varus thrust, defined as an abrupt increase of the knee varus angle during weight-bearing in gait, has been shown to be present in patients with moderate to severe knee osteoarthritis and is considered to be one of the risk factors for progression of symptomatic medial knee osteoarthritis. We evaluated the presence and magnitude of varus thrust and its relation with the Knee Adduction Moment in women with early medial knee osteoarthritis, and compared it to that in a group of controls and in a group of subjects with established medial knee osteoarthritis.Methods: Twenty-seven women with early medial knee osteoarthritis, 20 women with established medial knee osteoarthritis and 24 asymptomatic controls were evaluated. Varus thrust was estimated as an increase of the knee varus angle during the weight-bearing phase of gait at self-selected speed, assessed by 3D motion analysis.Findings: Varus thrust was significantly higher in both early and established osteoarthritis groups compared to the control group (P<0.001), but not different between osteoarthritis groups. While the knee adduction moments were higher than controls only in the established osteoarthritis group, the magnitude of varus thrust was significantly correlated with the second peak knee adduction moment.Interpretation: Higher varus thrust was found both in early and established stages of knee osteoarthritis, suggesting that problems with dynamic stabilization of the knee are present early in the development of knee osteoarthritis. This highlights the necessity of considering dynamic alignment in rehabilitation already in the early stages of the disease.

Effect of a Knee-Ankle-Foot Orthosis on Knee Kinematics and Kinetics in an Individual with Varus Knee Alignment

ABSTRACT Background Knee valgus braces are used to reduce knee load and varus deformities in individuals with medial compartment osteoarthritis (OA). The purpose of this study was to determine whether the kinematics and kinetics of the knee are improved when wearing a knee-ankle-foot orthosis (KAFO) compared with knee valgus braces while walking and stair climbing. Materials and Methods One male individual (with 10° of knee varus) was assessed with a control shoe, custom, and off-the-shelf (OTS) Unloader knee valgus braces, and a custom-made KAFO in situ during walking and stair climbing. Results The KAFO significantly reduced the knee varus angle compared with the shoe and both knee valgus braces during walking and stair climbing, as well as the first peak of the external knee adduction moment (EKAM) during walking and the knee adduction angular impulse (KAAI) during ascending compared with the shoe. No significant differences were noted between the custom and OTS knee valgus braces in any measures. Conclusions Knee-ankle-foot orthoses may be recommended for individuals with high knee varus angles.

Effect of preoperative factors on the clinical outcome of total knee arthroplasty

To analyze the effect of preoperative factors on the clinical outcome in patients receiving total knee replacement. From January 2011 to September 2013, 145 patients (206 knees; 22 males, 31 knees; 123 females, 175 knees)receiving total knee arthroplasty were successfully included in this study and followed up. The average ages was (66.5±7.6) years old(range, 51-83 years old). The data of preoperative factorsincludedgender, age, body mass index (BMI), preoperative range of motion (ROM), the knee varus angle, flexion deformity and preoperative the hospital for special surgery (HSS) scorewere collected. The correlation between preoperative factors and the clinical outcome (postoperative HSS score, postoperative ROM)after total knee replacement was evaluated statistically. The average follow-up time was 35 months (range, 24-56 months). The HSS score was increased from (55.1±7.6) preoperativelyto (89.3±5.1) postoperatively. ROM elevated from (95.6±10.0)°preoperatively to (115.1±7.8)° postoperatively.The correlation analysis showed that the postoperative ROM was positively correlated with the preoperative ROM, and was negatively correlated with the BMI, the knee varus angle(r=-0.864, -0.353, all P<0.01). The postoperative HSS score was positively correlated with preoperative ROM, preoperative HSS score(r=0.101, 0.244, P=0.033, P<0.01), and was negatively correlated with the BMI (r=-0.277, P=0.039). Total knee arthroplasty can definitely improve the function of knee joint. The BMI, the preoperative ROM, the knee varus angle and preoperative HSS score have influence on postoperative function of patients receiving total knee arthroplasty.

Ipsilateral varus knee alignment correlates with increased femoral stem anteversion in primary total hip arthroplasty.

The purpose of this study was to evaluate whether the ipsilateral knee alignment secondary to knee osteoarthritis affect positioning of the femoral component anteversion during total hip arthroplasty. Preoperative and postoperative computed tomography-based 3-D femoral models were reconstructed for 20 total hip arthroplasty patients. Prosthetic femoral stem and native femoral anteversion was measured and compared. An average increase by 4.5° ± 8.1° in femoral anteversion was found following total hip arthroplasty (p = 0.02). Strong positive correlation was found between the knee varus angle and the changes in femoral anteversion (R = 0.87, p&lt;0.0001). The knee alignment was an independent factor for predicting the intraoperative positioning of femoral stem anteversion. The ipsilateral knee varus deformity should be considered to optimise the femoral component position during contemporary total hip arthroplasty.

Frontal plane biomechanics of the operated and non-operated knees before and after unilateral total knee arthroplasty

BackgroundAfter unilateral total knee arthroplasty, frontal plane loading patterns on the operated knee remain pathological in the long term, but it is unclear how they change in the early postoperative period. Additionally, researchers have suggested that the non-operated knee bears greater frontal plane loads postoperatively, but this effect is unclear. The objective of the present study was to compare the preoperative and early postoperative frontal plane loading patterns of both knees after unilateral total knee arthroplasty. MethodsFifty patients with end-stage knee osteoarthritis were examined prior to and six weeks after surgery. Patients underwent a three-dimensional gait analysis that determined the frontal plane loading patterns of knee varus angle and knee adduction moment during gait, and completed self-evaluative questionnaires and functional tests. FindingsThere were no significant loading differences between limbs preoperatively. The operated knee showed large reductions in varus angle and adduction moment after surgery (all p<0.001). The non-operated knee showed no increases in varus angle or adduction moment, but did show a small reduction in the adduction moment (p<0.001). Both knees showed reduction in pain after surgery (p<0.001) and the operated Knee Society Score improved after surgery (p=0.01). InterpretationTotal knee arthroplasty reduces frontal plane loading in the operated knee and does not worsen frontal plane loading in the non-operated knee. Therapy after surgery should focus on retaining the reduction in knee adduction moment in the operated knee and preventing further worsening loading patterns in the non-operated knee.

BIOMECHANICAL STUDY ON THE EFFECTS OF VARUS AND VALGUS DEFORMITIES OF THE KNEE ON THE WEIGHT-BEARING DOME OF ACETABULUM

This study's purpose was to investigate the biomechanical effects of varus and valgus knee deformities in different degrees on the acetabulum's weight-bearing dome. We collected six lower extremity specimens from three fresh adult male cadavers, including the L5 vertebral body, pelvis, bilateral hips, bilateral knees and lower leg sections. We visually examined all specimens and then X-rayed them to exclude the presence of hip and knee pathology. We adjusted the tibiofemoral angle to 180° (knee varus at 10°, Group A), 190° (knee varus at 20°, Group B), 160° (knee valgus at 10°, Group C) and 150° (knee valgus at 20°, Group D) using the external fixator, respectively, fixed them, respectively, and then monitored them through the above 3D laser scanning imager. We found the acetabulum's weight-bearing dome area, stress and stress distribution by loading and coloring on the pressure-sensitive film. We measured them using a FPD-305 density meter and FPD-306 pressure converter. We compared the areas, average stresses and peak stresses of the acetabulum's weight-bearing dome between groups B and D and group A, respectively. The differences between groups B and D had no significance. Compared to group A's area, average stress and peak stress, the areas of groups C and E decreased, and their average stresses and peak stresses increased significantly. The differences between groups B and C and groups D and E were also significant. Due to different degrees of knee varus and valgus angles, the areas of the weight-bearing acetabulum dome, average stress and peak stress are different. The knee varus and valgus at 20° were statistically significant, which may be the key pathogenesis of hip arthritis.

Courses of change in knee adduction moment and lateral thrust differ up to 1year after TKA.

In total knee arthroplasty (TKA), dynamic knee loading may loosen the artificial joint and bone or cause polyethylene wear after prolonged use. TKA decreases knee adduction moment at 6months, but this effect is lost by 1year post-operatively. However, lateral thrust after TKA has not been clarified. We hypothesized that like knee adduction moment, lateral thrust would return to baseline levels by 1year post-operatively. Participants were 15 patients who underwent TKA for medial knee OA. Japanese Orthopaedic Association (JOA) score, numeric rating scale, and gait analysis (measurement of peak knee adduction moment, knee varus angle at peak knee adduction moment, lateral thrust, and gait speed) were performed preoperatively (baseline) and 3weeks, 3 and 6months, and 1year post-operatively. JOA score improved from 55±9.8 to 78±12.1 at 1year post-operatively, and pain decreased significantly from baseline at each follow-up (p<0.001). Significant increases in gait speed were observed at 6months and 1year (p<0.001). Peak knee adduction moment during stance phase was significantly lower at 3weeks, 3months, and 6months compared to baseline (p<0.05), but no significant changes were seen at 1year. Knee varus at peak knee adduction moment did not differ significantly between any measurement points, while lateral thrust was decreased at 6months and 1year compared to baseline (p<0.05). Temporal courses of changes up to 1year after TKA differed between knee adduction moment and lateral thrust, so our hypothesis was rejected. IV.

Kinematic analysis of knee varus and rotation movements at the initial stance phase with severe osteoarthritis of the knee

BackgroundThe purposes of this study were to understand the kinematics changes in the frontal and horizontal planes with severe medial knee OA at the stance phase and to examine the relationship between varus and rotational movements. MethodsThe OA group comprised 18 knees in 12 subjects (five men, seven women) with a Kellgren–Lawrence grade of three or four in at least one knee. From the results of gait analysis, we calculated Spearman rank-correlation coefficients for the following items: varus angle at initial contact (IC); varus angle at loading response (LR); amount of varus thrust from IC to LR; rotational angle at IC; rotational angle at LR and amount of rotational angle change from IC to LR. ResultsThe results indicated that, as the external rotation angle at IC and internal rotational movement from IC to LR increased, the maximum varus angle to LR showed a tendency to become large. In addition, varus thrust showed a tendency to become larger as the external rotation angles increased at IC and LR. The subjects with severe knee OA showed a strong correlation between the knee varus angle at IC and at LR. Furthermore, an increase in movement to internal rotation of the knee during the initial stance phase increased the knee varus angle at LR. ConclusionsThe control of the rotational movement according to the extent of varus thrust during the initial stance phase may have possible effects to decrease the load on the medial compartment of the knee.

Ankle Dorsiflexion Displacement During Landing is Associated With Initial Contact Kinematics but not Joint Displacement.

The ankle, knee, and hip joints work together in the sagittal plane to absorb landing forces. Reduced sagittal plane motion at the ankle may alter landing strategies at the knee and hip, potentially increasing injury risk; however, no studies have examined the kinematic relationships between the joints during jump landings. Healthy adults (N = 30; 15 male, 15 female) performed jump landings onto a force plate while three-dimensional kinematic data were collected. Joint displacement values were calculated during the loading phase as the difference between peak and initial contact angles. No relationship existed between ankle dorsiflexion displacement during landing and three-dimensional knee and hip displacements. However, less ankle dorsiflexion displacement was associated with landing at initial ground contact with larger hip flexion, hip internal rotation, knee flexion, knee varus, and smaller plantar flexion angles. Findings of the current study suggest that restrictions in ankle motion during landing may contribute to contacting the ground in a more flexed position but continuing through little additional motion to absorb the landing. Transverse plane hip and frontal plane knee positioning may also occur, which are known to increase the risk of lower extremity injury.