Effects of severity of degeneration on gait patterns in patients with medial knee osteoarthritis

Sex-related differences in gait characteristics and their associations with symptoms in individuals with patellofemoral osteoarthritis

BACKGROUND

Patellofemoral osteoarthritis (OA) is an important subgroup of knee OA. However, the influence of sex on gait characteristics in patients with patellofemoral OA is unknown.

RESEARCH QUESTION

Compare gait characteristics in females and males with patellofemoral OA and investigate their associations with patellofemoral joint-related symptoms and limitations.

METHODS

Mixed effects polynomial regression models compared knee flexion-extension and adduction moments, knee flexion angles, and vertical ground reaction forces over 100% of stance between 26 females and 22 males with patellofemoral OA, with and without adjustment for walking speed and body mass. Multivariable linear regression models were then used to investigate the associations of gait characteristics with symptoms and limitations measured with the Knee injury and Osteoarthritis Outcome Score Patellofemoral Pain and Osteoarthritis (KOOS-PF) Subscale. Models included a sex-by-gait interaction term, and if significant, separate models were built for females and males.

RESULTS

While controlling for walking speed and body mass, females had lower knee flexion moment (6-19% and 97-100% of stance), knee extension moment (45-86% of stance), knee adduction moment (3-37% and 69-99% of stance), vertical ground reaction force (1-97% of stance) and knee flexion angle (90-100% of stance) compared with males, when fitted over 100% of stance. Lower cadence, lower knee flexion angular impulse, and higher peak knee flexion angle were associated with worse KOOS-PF scores. Associations were not modified by sex.

SIGNIFICANCE

There are distinct sex-based differences in gait characteristics throughout stance with patellofemoral OA when adjusting for body mass and walking speed. Lower cadence and knee flexion angular impulse, and higher peak knee flexion angle were associated with more extreme patellofemoral joint-related symptoms and limitations.

Diverse parameters of ambulatory knee moments differ with medial knee osteoarthritis severity and are combinable into a severity index

Objective: To characterize ambulatory knee moments with respect to medial knee osteoarthritis (OA) severity comprehensively and to assess the possibility of developing a severity index combining knee moment parameters. Methods: Nine parameters (peak amplitudes) commonly used to quantify three-dimensional knee moments during walking were analyzed for 98 individuals (58.7 ± 9.2 years old, 1.69 ± 0.09 m, 76.9 ± 14.5 kg, 56% female), corresponding to three medial knee osteoarthritis severity groups: non-osteoarthritis (n = 22), mild osteoarthritis (n = 38) and severe osteoarthritis (n = 38). Multinomial logistic regression was used to create a severity index. Comparison and regression analyses were performed with respect to disease severity. Results: Six of the nine moment parameters differed statistically significantly among severity groups (p ≤ 0.039) and five reported statistically significant correlation with disease severity (0.23 ≤ |r| ≤ 0.59). The proposed severity index was highly reliable (ICC = 0.96) and statistically significantly different between the three groups (p < 0.001) as well as correlated with disease severity (r = 0.70). Conclusion: While medial knee osteoarthritis research has mostly focused on a few knee moment parameters, this study showed that other parameters differ with disease severity. In particular, it shed light on three parameters frequently disregarded in prior works. Another important finding is the possibility of combining the parameters into a severity index, which opens promising perspectives based on a single figure assessing the knee moments in their entirety. Although the proposed index was shown to be reliable and associated with disease severity, further research will be necessary particularly to assess its validity.

IJES-OA Net: A residual neural network to classify knee osteoarthritis from radiographic images based on the edges of the intra-joint spaces

Among the musculoskeletal disorders in the world, osteoarthritis is the most common, affecting most of the body joints, especially the knee. Clinical radiographic imaging methods are commonly used to diagnose osteoarthritis thanks to their cheapness and availability. Due to the low quality and indiscernibility of these images, however, accurate osteoarthritis diagnosis has always faced inaccuracies, such as the wrong diagnosis. One of the osteoarthritis hallmarks is joint space narrowing. Thus, its degree and severity can be determined relatively by assessing the space between the bones in the joint. Therefore, in this research, a deep residual neural network, termed IJES-OA Net, is presented to automatically grade (classify) the severity of knee osteoarthritis via radiographs. This is achieved by tuning it in a way to have it focused on the distance of the edges of the bones inside the knee joint. Experimental results which are conducted on MOST (for training) and OAI (for validation and testing) datasets show that the IJES-OA Net achieves high average accuracy as well as average precision (80.23% and 0.802, respectively) while having less complexity compared to other methods. Additionally, the resulting attention maps from IJES-OA Net are accurate enough that increase experts' reliance on the provided results.

The effect of foot position during static calibration trials on knee kinematic and kinetics during walking

BACKGROUND

Gait analysis has been used extensively for computing knee kinematics and kinetics, in particular, in healthy and impaired individuals. One variable assessed is the external knee adduction moment (EKAM). Variations in EKAM values between investigations may be caused by changes in static standing position, especially foot placement angles which may increase or reduce any differences seen.

PURPOSE OF THE STUDY

The current study aimed to explore the influence of static trial foot position on knee kinematic and kinetic variables during walking.

METHODS

Twelve healthy male participants completed three different static standing trials; 1) 20-degrees toe-in, 2) 0° and 3) 20-degrees toe-out before walking at their own pace during a lower limb kinematics and kinetics assessment. First and second peak EKAM was compared between static foot position trials, as well other knee kinematic and kinetic outcomes. Repeated measures ANOVA was used with post hoc pairwise comparison to determine the differences between static foot position trials.

RESULTS

The first peak of EKAM was significantly smaller in the 20^o toe-out angle, than the 20^o toe-in angle (p = 0.04-8.16% reduction). Furthermore, significant changes were found in peak knee kinematics and kinetics variables (adduction angle, external rotation angle, knee flexion moment external rotation moment, abduction angle and internal rotation angle) in the different positions.

CONCLUSION

Modification in static foot position between study visits may result in changes especially in the 1st peak EKAM and other kinematics and kinetics variables during walking. Therefore, standardisation of static foot position should be utilised in longitudinal studies to ensure changes in EKAM are not masked or accentuated between assessments.

Properties of the iliotibial band and their relationships with gait parameters among patients with knee osteoarthritis

This study aimed to determine the thickness and stiffness of the iliotibial band (ITB) in patients with knee osteoarthritis (KOA) and to identify the gait parameters that are associated with ITB properties. Eighteen female patients with radiographically diagnosed medial KOA and knee pain (age: 69.7 ± 5.9 years, body mass index: 23.0 ± 3.1 kg/m² ) and 22 age-matched female individuals without knee pain (age: 69.1 ± 7.0 years, body mass index: 21.6 ± 3.6 kg/m² ) were included. Shear wave elastography images were obtained at the height of the proximal pole of the patella with the participants in the supine position, and the ITB thickness and shear wave velocity, which is a surrogate measure of stiffness, were calculated. In patients with KOA, the knee and hip joint angles and moments during walking were calculated using a motion analysis system. The shear wave velocity was significantly higher in patients with KOA than in asymptomatic adults (11.3 ± 1.0 vs. 10.0 ± 1.8 m/s, respectively; p = 0.010); however, the thickness did not differ between them (2.1 ± 0.3 vs. 2.0 ± 0.3 mm, respectively; p = 0.705). The time-integral value of the knee adduction moment (β = 0.507, p = 0.032) and maximum value of the hip flexion moment (β = 0.498, p = 0.036) were associated with the shear wave velocity. Meanwhile, no parameters were associated with the thickness. The ITB was stiffer in patients with KOA than in asymptomatic adults; such a stiffer ITB was associated with greater knee adduction and hip flexion moments during walking. Clinical Significance: Greater mechanical loading was associated with a stiffer ITB in patients with KOA.

The Effect of Core Stabilization Training on Improving Gait and Self-Perceived Function in Patients with Knee Osteoarthritis: A Single-Arm Clinical Trial

The treatment of patients with knee osteoarthritis is typically focused on the involved lower extremity. There is a gap in the literature concerning the effectiveness of core stabilization training on the treatment of patients with knee osteoarthritis. This investigation aimed to determine whether core stabilization improved the gait and functional ability of patients with knee osteoarthritis. Eighteen participants with knee osteoarthritis completed the six-week core stabilization intervention. Participants completed the gait motion analysis and the Knee Injury and Osteoarthritis Outcome Score to assess self-perceived function, pre- and post-intervention. Gait speed improved (p = 0.006, d = 0.59), while the external knee adduction moment decreased (p = 0.034, d = −0.90). Moreover, self-reported function improved (p < 0.001, d = 1.26). The gait speed and external knee adduction moment changes met minimal detectable change thresholds, while gait speed also met the minimal clinically important difference. A six-week core stabilization program can thus improve gait speed and reduce the external knee adduction moment, which is tied to disease progression. Increased functional scores post-intervention indicate an important clinical improvement. Core stabilization training is a safe and potentially effective treatment option for this population.

Beneficial Effects and Potential Mechanisms of Tai Chi on Lower Limb Osteoarthritis: A Biopsychosocial Perspective

Lower limb osteoarthritis (OA) is a chronic, multifactorial disease characterized by impaired physical function, chronic pain, compromised psychological health and decreased social functioning. Chronic inflammation plays a critical role in the pathophysiology of OA. Tai Chi is a type of classical mind-body exercise derived from ancient Chinese martial arts. Evidence supports that Tai Chi has significant benefits for relieving lower limb OA symptoms. Using a biopsychosocial framework, this review aims to elucidate the beneficial effects of Tai Chi in lower limb OA and disentangle its potential mechanisms from the perspective of biology, psychology, and social factors. Complex biomechanical, biochemical, neurological, psychological, and social mechanisms, including strengthening of muscles, proprioception improvement, joint mechanical stress reduction, change of brain activation and sensitization, attenuation of inflammation, emotion modulation and social support, are discussed.

Inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait in patients with knee osteoarthritis

BACKGROUND

Gait analysis has been used for decades to quantify knee function in patients with knee osteoarthritis; however, it is unknown whether and to what extent inter-laboratory differences affect the comparison of gait data between studies. Therefore, the aim of this study was to perform an inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait of patients with knee osteoarthritis.

METHODS

Knee biomechanics and muscle activation patterns from patients with knee osteoarthritis were analyzed, previously collected at Dalhousie University (DAL: n = 55) and Amsterdam UMC, VU medical center (VUmc: n = 39), using their in-house protocols. Additionally, one healthy male was measured at both locations. Both direct comparisons and after harmonization of components of the protocols were made. Inter-laboratory comparisons were quantified using statistical parametric mapping analysis and discrete gait parameters.

RESULTS

The inter-laboratory comparison showed offsets in the sagittal plane angles, moments and frontal plane angles, and phase shifts in the muscle activation patterns. Filter characteristics, initial contact identification and thigh anatomical frame definitions were harmonized between the laboratories. After this first step in protocol harmonization, the offsets in knee angles and sagittal plane moments remained, but the inter-laboratory comparison of the muscle activation patterns improved.

CONCLUSIONS

Inter-laboratory differences obstruct valid comparisons of gait datasets from patients with knee osteoarthritis between gait laboratories. A first step in harmonization of gait analysis protocols improved the inter-laboratory comparison. Further protocol harmonization is recommended to enable valid comparisons between labs, data-sharing and multicenter trials to investigate knee function in patients with knee osteoarthritis.

Neuromechanical assessment of knee joint instability during perturbed gait in patients with knee osteoarthritis

Knee joint instability is frequently reported by patients with knee osteoarthritis (KOA). Objective metrics to assess knee joint instability are lacking, making it difficult to target therapies aiming to improve stability. Therefore, the aim of this study was to compare responses in neuromechanics to perturbations during gait in patients with self-reported knee joint instability (KOA-I) versus patients reporting stable knees (KOA-S) and healthy control subjects. Forty patients (20 KOA-I and 20 KOA-S) and 20 healthy controls were measured during perturbed treadmill walking. Knee joint angles and muscle activation patterns were compared using statistical parametric mapping and discrete gait parameters. Furthermore, subgroups (moderate versus severe KOA) based on Kellgren and Lawrence classification were evaluated. Patients with KOA-I generally had greater knee flexion angles compared to controls during terminal stance and during swing of perturbed gait. In response to deceleration perturbations the patients with moderate KOA-I increased their knee flexion angles during terminal stance and pre-swing. Knee muscle activation patterns were overall similar between the groups. In response to sway medial perturbations the patients with severe KOA-I increased the co-contraction of the quadriceps versus hamstrings muscles during terminal stance. Patients with KOA-I respond to different gait perturbations by increasing knee flexion angles, co-contraction of muscles or both during terminal stance. These alterations in neuromechanics could assist in the assessment of knee joint instability in patients, to provide treatment options accordingly. Furthermore, longitudinal studies are needed to investigate the consequences of altered neuromechanics due to knee joint instability on the development of KOA.

Side to side kinematic gait differences within patients and spatiotemporal and kinematic gait differences between patients with severe knee osteoarthritis and controls measured with inertial sensors

BACKGROUND

Kinematic changes associated with knee osteoarthritis (OA) have been traditionally measured with camera-based gait analysis. Lately, inertial sensors have become popular for gait analysis with the advantage of being less time consuming and not requiring a dedicated laboratory.

RESEARCH QUESTION

Do spatiotemporal and discrete kinematic gait parameters measured with the inertial sensor system RehaGait® differ between the affected and unaffected side in patients with unilateral knee OA and between patients with severe knee OA and asymptomatic control subjects? Do these differences have a similar magnitude as those reported in the literature?

METHODS

Twenty-two patients with unilateral knee OA scheduled for total knee replacement and 46 age matched control subjects were included in this study. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle joint were measured using the RehaGait® system while walking at a self-selected speed for a distance of 20 m and compared between groups.

RESULTS

Patients with knee OA had slower walking speed, longer stride duration, shorter stride length and lower cadence (P < 0.001). Peak knee flexion during stance and swing was lower in the affected than the unaffected leg (-4.8° and -6.1°; P < 0.01). Peak knee flexion during stance and swing (-5.2° and -8.8°; P < 0.01) and knee range of motion during loading response and swing (-3.6° and -4.4°; P < 0.01) were lower than in the control group.

SIGNIFICANCE

These side to side differences within patients and differences between patients with knee OA and control subjects agree with known gait alterations measured with camera-based systems. The RehaGait® inertial sensor system can detect gait alterations in patients with knee OA and is suitable for gait analysis in a clinical environment.

Effects of knee osteoarthritis severity on inter-joint coordination and gait variability as measured by hip-knee cyclograms

Inter-joint coordination and gait variability in knee osteoarthritis (KOA) has not been well investigated. Hip-knee cyclograms can visualize the relationship between the hip and knee joint simultaneously. The aim of this study was to elucidate differences in inter-joint coordination and gait variability with respect to KOA severity using hip-knee cyclograms. Fifty participants with KOA (early KOA, n = 20; advanced KOA, n = 30) and 26 participants (≥ 50 years) without KOA were recruited. We analyzed inter-joint coordination by hip-knee cyclogram parameters including range of motion (RoM), center of mass (CoM), perimeter, and area. Gait variability was assessed by the coefficient of variance (CV) of hip-knee cyclogram parameters. Knee RoM was significantly reduced and total perimeter tended to be decreased with KOA progression. KOA patients (both early and advanced) had reduced stance phase perimeter, swing phase area, and total area than controls. Reduced knee CoM and swing phase perimeter were observed only in advanced KOA. Both KOA groups had a greater CV for CoM, knee RoM, perimeter (stance phase, swing phase and total) and swing phase area than the controls. Increased CV of hip RoM was only observed in advanced KOA. These results demonstrate that hip-knee cyclograms can provide insights into KOA patient gait.

Comparing walking biomechanics of older females in maximal, minimal, and traditional shoes

BACKGROUND

Knee osteoarthritis (OA) is a degenerative joint disease that affects millions of individuals each year. Several biomechanical variables during walking have been identified as risk factors for developing knee OA, including the peak external knee adduction moment (KAM) and the knee flexion angle at initial contact. Many interventions have been studied to help mitigate these risk factors, including footwear. However, it is largely unknown how varying shoe cushioning may affect walking biomechanics related to knee OA risk.

RESEARCH QUESTION

What is the effect of maximally and minimally cushioned shoes on walking biomechanics compared to a traditionally cushioned shoe in older females?

METHODS

Walking biomechanics in three shoes (maximal, traditional, minimal) were collected on 16 healthy females ages 50-70 using an 8-camera 3D motion capture system and two embedded force plates. Key biomechanical variables related to knee OA disease risk were compared between shoes using repeated measures ANOVAs.

RESULTS

The KAM was significantly larger in the maximal shoe (p = 0.005), while the knee flexion angle at initial contact was significantly larger in both the maximal and minimal shoe compared to the traditional shoe (p = .000). Additionally, the peak knee flexion angle (p = .000) and the loading rates of the vertical ground reaction force were (instantaneous: p = 0.001; average: p = .010) were significantly higher in the minimal shoe.

SIGNIFICANCE

While these results are specific to the shoes used in this study, clinicians should exercise caution in prescribing maximal or minimal shoes to females in this age group who may be at risk of knee OA given these results. Research is needed on the effect of these shoes in patients with knee OA.

Kinematic changes in patients with severe knee osteoarthritis are a result of reduced walking speed rather than disease severity

BACKGROUND

Kinematic changes in patients with knee osteoarthritis (OA) have been extensively studied. Concerns have been raised whether the measured spatiotemporal and kinematic alterations are associated with disease progression or merely a result of reduced walking speed.

RESEARCH QUESTION

The purpose of this study was to investigate the effect of walking speed on kinematic parameters in patients with knee OA using statistical parametric mapping (SPM).

METHODS

Twenty-three patients with unilateral knee OA scheduled for a total knee replacement and 28 age matched control subjects were included in this study. Spatiotemporal parameters and sagittal plane kinematics were measured in the hip, knee, and ankle using the inertial sensors system RehaGait® while walking at a self-selected normal (patients and controls) and slow walking speed (controls) for a distance of 20 m. Gait parameters were compared between groups for self-selected walking speed and for matched walking speed using SPM with independent sample t tests.

RESULTS

At self-selected walking speed, patients had significantly lower knee flexion during stance (maximum difference, -6.8°) and during swing (-11.0°), as well as higher ankle dorsiflexion during stance phase (+12.5°) and lower peak hip extension at the end of stance compared to controls (+4.2°). At matched speed, there were no significant differences in joint kinematics between groups.

SIGNIFICANCE

Differences in sagittal plane gait kinematics between patients with knee OA and asymptomatic controls appear to be mainly a result of reduced walking speed. These results emphasize the importance of considering walking speed in research on gait kinematics in patients with knee OA and in clinical trials using gait parameters as outcome measures.

Measuring three-dimensional tibiofemoral kinematics using dual-slice real-time magnetic resonance imaging

PURPOSE

The purpose of this study is to propose and evaluate a slice-to-volume registration (SVR) method integrating an advanced dual-slice real-time magnetic resonance image (MRI) and three-dimensional (3D) MRI volume of the tibiofemoral joint for determining their 3D kinematics.

METHODS

The real-time and 3D MRI of the knee were collected from 12 healthy adults at 5 static flexion positions and during dynamic flexion/extension movement. The 3D positions and orientations of the femur and tibia were obtained by registering their volumetric models constructed from the 3D MRI to dual-slice real-time MRI using an optimization process. The proposed method was quantitatively evaluated for its performance in terms of the robustness and measurement accuracy, and compared to those of a single-slice SVR method. Its repeatability in measuring knee kinematics during flexion/extension movement was also determined.

RESULTS

In comparison to the single-slice SVR method, the dual-slice method was significantly superior, giving a successful registration rate > 95%, a bias less than 0.5 mm in translations and 0.6° in rotations and a precision <0.7 mm in translations and 0.9° in rotations for determining the 3D tibiofemoral poses. For repeatability of the dual-slice SVR in measuring tibiofemoral kinematics during dynamic flexion/extension, the means of the time-averaged standard deviations were <0.9° for joint angles and 0.5 mm for joint translations.

CONCLUSION

A dual-slice SVR method in conjunction with real-time MRI has been developed and evaluated for its performance in measuring 3D kinematics of the tibiofemoral joint in 12 young adults in terms of the accuracy, robustness, and repeatability. The proposed MRI-based 3D measurement method provides a noninvasive and ionizing radiation-free approach for 3D kinematic measurement of the tibiofemoral joint, which will be helpful for future academic and clinical applications.

Trunk movement asymmetry associated with pain, disability, and quadriceps strength asymmetry in individuals with knee osteoarthritis: a cross-sectional study

OBJECTIVE

This study examined 1) the clinical relevance of trunk movement asymmetry, which was evaluated using a trunk-mounted inertial measurement unit (IMU), and 2) the relationship between trunk movement asymmetry and lower limb muscle strength asymmetry in individuals with knee osteoarthritis (OA).

DESIGN

One-hundred-thirty-one participants (mean age, 74.2 years; 71.8% female; Kellgren and Lawrence [K&L] grade ≥1) underwent gait analysis at their preferred pace for IMU-based measurement of trunk movement asymmetry (harmonic ratio [HR] and improved HR). The isometric strength of quadriceps and hip abductors was evaluated using a hand-held dynamometer. Pain and disability level were evaluated using a validated self-reported questionnaire. Multiple regression analyses with covariate adjustment were performed to examine the relationship between trunk movement asymmetry (independent variable) and pain, disability level, or muscle strength asymmetry (dependent variables).

RESULTS

Individuals with severe knee OA (K&L grade ≥3) had increased trunk movement asymmetry in the medio-lateral axis compared to those with a K&L grade of 1. Increased trunk movement asymmetry was associated with a greater knee pain and disability. The increased trunk movement asymmetry was significantly associated with an increase in the asymmetry of quadriceps strength, but not with asymmetry in the strength of hip abductor.

CONCLUSION

Our findings indicate that increased medio-lateral trunk movement asymmetry may be an indicator of impairment, rather than adaptation, in individuals with knee OA. This preliminary finding warrants validation by future study. Paying close attention to medio-lateral trunk movement asymmetry may be key to our understanding of OA-related pain and disability.

Which osteoarthritic gait features recover following total knee replacement surgery?

Background

Gait analysis can be used to measure variations in joint function in patients with knee osteoarthritis (OA), and is useful when observing longitudinal biomechanical changes following Total Knee Replacement (TKR) surgery. The Cardiff Classifier is an objective classification tool applied previously to examine the extent of biomechanical recovery following TKR. In this study, it is further developed to reveal the salient features that contribute to recovery towards healthy function.

Methods

Gait analysis was performed on 30 patients before and after TKR surgery, and 30 healthy controls. Median TKR follow-up time was 13 months. The combined application of principal component analysis (PCA) and the Cardiff Classifier defined 18 biomechanical features that discriminated OA from healthy gait. Statistical analysis tested whether these features were affected by TKR surgery and, if so, whether they recovered to values found for the controls.

Results

The Cardiff Classifier successfully discriminated between OA and healthy gait in all 60 cases. Of the 18 discriminatory features, only six (33%) were significantly affected by surgery, including features in all three planes of the ground reaction force (p<0.001), ankle dorsiflexion moment (p<0.001), hip adduction moment (p = 0.003), and transverse hip angle (p = 0.007). All but two (89%) of these features remained significantly different to those of the control group after surgery.

Conclusions

This approach was able to discriminate gait biomechanics associated with knee OA. The ground reaction force provided the strongest discriminatory features. Despite increased gait velocity and improvements in self-reported pain and function, which would normally be clinical indicators of recovery, the majority of features were not affected by TKR surgery. This TKR cohort retained pre-operative gait patterns; reduced sagittal hip and knee moments, decreased knee flexion, increased hip flexion, and reduced hip adduction. The changes that were associated with surgery were predominantly found at the ankle and hip, rather than at the knee.

Biomechanical Response to Osteoarthritis Pain Treatment May Impair Long-Term Efficacy

Pain has an important physiologic role and acts with or stimulates motor system adaptations to protect tissue from threats of damage. Although clinically beneficial, removing the protective pain response may have negative consequence in osteoarthritis, a mechanically mediated disease. We hypothesize motor system adaptations to joint pain and its treatment may impact osteoarthritis progression, thereby limiting efficacy of pain therapies.

Clinical gait evaluation of patients with knee osteoarthritis

Knee osteoarthritis (KOA) is the most common osteoarthritis in lower limbs, and gait measurement is important to evaluate walking function of KOA patients before and after treatment. The third generation Intelligent Device for Energy Expenditure and Activity (IDEEA3) is a portable gait analysis system to evaluate gaits. This study is to evaluate the accuracy and reliability of IDEEA3 for gait measurement of KOA patients. Meanwhile, gait differences between KOA patients and healthy subjects are examined. Twelve healthy volunteers were recruited for measurement comparison of gait cycle (GC), cadence, step length, velocity and step counts between a motion analysis system and a high-speed camera (GoPro Hero3). Twenty-three KOA patients were recruited for measurement comparison of former five parameters between GoPro Hero3 and IDEEA3. Paired t-test, Concordance Correlation Coefficient (CCC) and Intraclass Correlation Coefficient (ICC) were used for data analysis. All p-values of paired t-tests for GC, cadence, step length and velocity were greater than 0.05 while all CCC and ICC results were above 0.95. The measurements of GC, cadence, step length, velocity and step counts by motion analysis system are highly consistent with the measurements by GoPro Hero3. The measurements of former parameters by GoPro Hero3 are not statistically different from the measurements by IDEEA3. IDEEA3 can be effectively used for the measurement of GC, cadence, step length, velocity and step counts in KOA patients. The KOA patients walk with longer GC, lower cadence, shorter step length and slower speed compared with healthy subjects in natural speed with flat shoes.

Gait analysis of patients with knee osteoarthritis highlights a pathological mechanical pathway and provides a basis for therapeutic interventions

Knee osteoarthritis (OA) is a painful and incapacitating disease affecting a large portion of the elderly population, for which no cure exists. There is a critical need to enhance our understanding of OA pathogenesis, as a means to improve therapeutic options.

Knee OA is a complex disease influenced by many factors, including the loading environment. Analysing knee biomechanics during walking - the primary cyclic load-bearing activity - is therefore particularly relevant.

There is evidence of meaningful differences in the knee adduction moment, flexion moment and flexion angle during walking between non-OA individuals and patients with medial knee OA. Furthermore, these kinetic and kinematic gait variables have been associated with OA progression.

Gait analysis provides the critical information needed to understand the role of ambulatory biomechanics in OA development, and to design therapeutic interventions. Multidisciplinary research is necessary to relate the biomechanical alterations to the structural and biological components of OA.

Cite this article: Favre J, Jolles BM. Analysis of gait, knee biomechanics and the physiopathology of knee osteoarthritis in the development of therapeutic interventions. EFORT Open Rev 2016;1:368-374. DOI: 10.1302/2058-5241.1.000051.

Effect of total knee replacement surgery and postoperative 12 month home exercise program on gait parameters

OBJECTIVE

To evaluate the effects of surgery and a postoperative progressive home exercise program on gait parameters among individuals operated with total knee arthroplasty.

DESIGN

Single blinded randomized controlled trial.

SUBJECTS

108 patients (84 females, 24 males, mean age 69 years).

INTERVENTIONS

Patients were equally randomized into an exercise group (EG) and control group (CG). The 12-months progressive home exercise program starting two months postoperatively was compared to usual care.

METHODS

Gait analysis was performed using the Gaitrite electronic walkway system. In addition, knee extension and flexion strength were measured by a dynamometer preoperatively, and pain on visual analog scale (VAS) at two months and 14 months postoperatively.

RESULTS

At the 12-month follow-up, maximal gait velocity (p=0.006), cadence (p=0.003) and stance time (p=0.039) showed a greater increase among EG than CG. All the other gait parameters improved among both groups, but with not statistically discernible difference between groups. Weak correlations were found between changes in maximal gait velocity and the knee extension (r=-0.31, p=0.002), flexion strength (r=0.28, p=0.004) and pain during loading (r=-0.27, p=0.005) values.

CONCLUSION

The intervention produced statistically significant changes in maximal gait velocity, cadence and stance times in the exercise group compared to controls. Although the average change was small it is of importance that biggest changes occurred in those with low performance.

Strategies to reduce joint load in the medial compartment of the knee during gait in individuals with osteoarthritis: a review of the literature

Abstract Introduction: Increased joint load on the medial compartment of the knee during gait is a mechanical factor responsible for pain and progression of medial knee osteoarthritis. The knee external adductor moment of force is a kinetic parameter that correlates with the joint load in the medial compartment. Objective: The aim of this study was to conduct a narrative review of the biomechanics strategies during gait of individuals with medial knee osteoarthritis that reduce external adductor moment of force of the knee. Methods: The review of the literature was conducted in the databases MEDLINE, PUBMED and PEDro and included articles published between 2000 and 2011. It was selected transversal, theoretical, correlational and longitudinal studies as well as controlled clinical trials. Results: Decreased gait velocity, increased external rotation of the foot, increased internal abductor moment force of the hip and lateral trunk inclination to the side of the support limb are compensatory strategies used to reduce the external adductor moment of force of the knee during gait of individuals with medial knee osteoarthritis. The lateral trunk inclination may be beneficial in a short term, however it decreases the activity of the abductors muscles of the hip during the support phase of the gait favoring compensation that could result in the progression of medial knee osteoarthritis. Conclusion: Strengthening of the abductors muscles of the hip reduces pain, improves the function and prevents compensations that in a long term could possibly accelerate the progression of the medial knee osteoarthritis.

Loading rates during walking in adolescents with type II osteonecrosis secondary to pelvic osteotomy

Although Pemberton osteotomy has shown a high success rate even in older children, the occurrence of osteonecrosis (ON) remains one of the most severe complications, leading to premature osteoarthritis. Patients with type II ON are characterized by a valgus deformity of the proximal femur with altered musculoskeletal conditions, affecting the ability to attenuate or sustain the impulsive loading from the ground reaction force. It remains unclear whether these conditions also predispose these patients to harmful impulsive loadings. This study aimed to bridge the gap by measuring the loading rates in the lower limbs during level walking in adolescents who were treated during their infancy for unilateral developmental dysplasia of the hip by a pelvic osteotomy, with or without having developed type II ON. Patients with type II ON were found to display increased loading rates, not only at both the affected and unaffected hip, but also at other joints of the affected limb during level walking when compared to patients without ON changes (p < 0.05). These results suggest that patients with type II ON may be at a higher risk of developing premature hip osteoarthritis that is closely related to abnormal loading rates during gait. It is suggested that regular monitoring of joint loading rates in patients with type II ON is necessary for early identification of damaging loadings, and that early intervention aimed at reducing these loadings should be considered. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2199-2206, 2016.

An Automated Recording Method in Clinical Consultation to Rate the Limp in Lower Limb Osteoarthritis

For diagnosis and follow up, it is important to be able to quantify limp in an objective, and precise way adapted to daily clinical consultation. The purpose of this exploratory study was to determine if an inertial sensor-based method could provide simple features that correlate with the severity of lower limb osteoarthritis evaluated by the WOMAC index without the use of step detection in the signal processing. Forty-eight patients with lower limb osteoarthritis formed two severity groups separated by the median of the WOMAC index (G1, G2). Twelve asymptomatic age-matched control subjects formed the control group (G0). Subjects were asked to walk straight 10 meters forward and 10 meters back at self-selected walking speeds with inertial measurement units (IMU) (3-D accelerometers, 3-D gyroscopes and 3-D magnetometers) attached on the head, the lower back (L3-L4) and both feet. Sixty parameters corresponding to the mean and the root mean square (RMS) of the recorded signals on the various sensors (head, lower back and feet), in the various axes, in the various frames were computed. Parameters were defined as discriminating when they showed statistical differences between the three groups. In total, four parameters were found discriminating: mean and RMS of the norm of the acceleration in the horizontal plane for contralateral and ipsilateral foot in the doctor's office frame. No discriminating parameter was found on the head or the lower back. No discriminating parameter was found in the sensor linked frames. This study showed that two IMUs placed on both feet and a step detection free signal processing method could be an objective and quantitative complement to the clinical examination of the physician in everyday practice. Our method provides new automatically computed parameters that could be used for the comprehension of lower limb osteoarthritis. It may not only be used in medical consultation to score patients but also to monitor the evolution of their clinical syndrome during and after rehabilitation. Finally, it paves the way for the quantification of gait in other fields such as neurology and for monitoring the gait at a patient's home.

Effects of Tai Ji Quan training on gait kinematics in older Chinese women with knee osteoarthritis: A randomized controlled trial

BACKGROUND

Although Tai Ji Quan has been shown to relieve pain and improve functional mobility in people with knee osteoarthritis (OA), little is known about its potential benefits on gait characteristics among older Chinese women who have a high prevalence of both radiographic and symptomatic knee OA. This study aims to assess the efficacy of a tailored Tai Ji Quan intervention on gait kinematics for older Chinese women with knee OA.

METHODS

A randomized controlled trial involving 46 older women in Shanghai, China, with clinically diagnosed knee OA. Randomized (1:1) participants received either a 60 min Tai Ji Quan session (n = 23) 3 times weekly or a 60 min bi-weekly educational session (n = 23) for 24 weeks. Primary outcomes were changes in gait kinematic measures from baseline to 24 weeks. Secondary outcomes included changes in scores on the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Short Physical Performance Battery (SPPB).

RESULTS

After 24 weeks the Tai Ji Quan group demonstrated better performance in gait velocity (mean difference, 8.40 cm/s, p = 0.01), step length (mean difference, 3.52 cm, p = 0.004), initial contact angle (mean difference, 2.19°, p = 0.01), and maximal angle (mean difference, 2.61°, p = 0.003) of flexed knees during stance phase compared to the control group. In addition, the Tai Ji Quan group showed significant improvement in WOMAC scores (p < 0.01) (mean difference, -4.22 points in pain, p = 0.002; -2.41 points in stiffness, p < 0.001; -11.04 points in physical function, p = 0.006) and SPPB scores (mean difference, 1.22 points, p < 0.001).

CONCLUSION

Among older Chinese women with knee OA, a tailored Tai Ji Quan intervention improved gait outcomes. The intervention also improved overall function as indexed by the WOMAC and SPPB. These results support the use of Tai Ji Quan for older Chinese adults with knee OA to both improve their functional mobility and reduce pain symptomatology.

Baseline ambulatory knee kinematics are associated with changes in cartilage thickness in osteoarthritic patients over 5 years

Although kinematic alterations during walking have been reported with knee osteoarthritis (OA), there is a paucity of longitudinal data, therefore limiting our understanding of the role of kinematics in OA development. This study tested the hypothesis that less knee extension angle and less posterior displacement of the femur relative to the tibia during the heel-strike portion of the gait cycle are associated with greater loss of medial cartilage thickness during a follow-up period of five years. This study also tested for associations between flexion-extension angle and anterior-posterior displacement during other periods of the gait cycle and 5-year cartilage thinning. 16 subjects with moderate medial knee OA were tested with gait analysis and MRI at baseline and had a follow-up MRI after 5 years. Linear regressions were used to assess the relationship between changes in cartilage thickness and baseline kinematics using Pearson correlation coefficients. Multivariate regressions were also performed to adjust for gender, baseline age, BMI, walking speed, Kellgren/Lawrence grade, and baseline knee pain score. As hypothesized, baseline knee flexion angle and femoral displacement during heel-strike and other gait cycle periods were significantly associated with medial femoral and tibial cartilage thinning at the 5 year follow-up; these associations were strengthened after adjustment for covariates. This study provided new insight into the pathogenesis of knee OA where baseline knee kinematics were associated with longitudinal disease progression. These results could serve as a basis for developing newer gait modification interventions to reduce the risk for developing knee OA.

Gait analysis of patients with knee osteoarthritis before and after Chinese massage treatment

The objective of this study was to evaluate the effectiveness of Chinese massage therapy in patients with knee osteoarthritis (OA) by measuring lower-limb gait parameters. We recruited 20 women with knee OA, who then underwent Chinese massage therapy three times per week for 2 weeks. The patients underwent gait evaluation using a six-camera infrared motion analysis system. They completed Western Ontario and McMaster Universities Osteoarthritis Index questionnaires before and after treatment. We calculated the forward speed, step width, step length, total support time percentage, initial double support time percentage, and single support time percentage. We also measured the angles at the knee, hip, and ankle during the stance phase of walking. The results showed statistically significant mean differences in knee pain relief, alleviation of stiffness, and physical function enhancement after therapy (P < 0.05). The patients gained significantly faster gait speed, greater step width, and increased total support time percentage after the Chinese massage therapy (P < 0.05). There were no significant differences in the range of motion or initial contact angles of the knee, hip, or ankle during the stance phase of walking. We concluded that Chinese massage is a beneficial complementary treatment and an alternative therapy choice for patients with knee OA for short-term pain relief. Chinese massage may improve walking ability for these patients.

Experimentally reduced hip-abductor muscle strength and frontal-plane biomechanics during walking

CONTEXT

Researchers have postulated that reduced hip-abductor muscle strength may have a role in the progression of knee osteoarthritis by increasing the external knee-adduction moment. However, the relationship between hip-abductor strength and frontal-plane biomechanics remains unclear.

OBJECTIVE

To experimentally reduce hip-abduction strength and observe the subsequent changes in frontal-plane biomechanics.

DESIGN

Descriptive laboratory study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Eight healthy, recreationally active men (age = 27 ± 6 years, height = 1.75 ± 0.11 m, mass = 76.1 ± 10.0 kg).

INTERVENTION(S)

All participants underwent a superior gluteal nerve block injection to reduce the force output of the hip-abductor muscle group.

MAIN OUTCOME MEASURE(S)

Maximal isometric hip-abduction strength and gait biomechanical data were collected before and after the injections. Gait biomechanical variables collected during walking consisted of knee- and hip-adduction moments and impulses and the peak angles of contralateral pelvic drop, hip adduction, and ipsilateral trunk lean.

RESULTS

Hip-abduction strength was reduced after the injection (P = .001) and remained lower than baseline values at the completion of the postinjection gait data collection (P = .02). No alterations in hip- or knee-adduction moments (hip: P = .11; knee: P = .52) or impulses (hip: P = .16; knee: P = .41) were found after the nerve block. Similarly, no changes in angular kinematics were observed for contralateral pelvic drop (P = .53), ipsilateral trunk lean (P = .78), or hip adduction (P = .48).

CONCLUSIONS

A short-term reduction in hip-abductor strength was not associated with alterations in the frontal-plane gait biomechanics of young, healthy men. Further research is needed to determine whether a similar relationship is true in older adults with knee osteoarthritis.

Gait Biomechanics and Patient-Reported Function as Predictors of Response to a Hip Strengthening Exercise Intervention in Patients with Knee Osteoarthritis

Objective

Muscle strengthening exercises have been shown to improve pain and function in adults with mild-to-moderate knee osteoarthritis, but individual response rates can vary greatly. Predicting individuals who respond and those who do not is important in developing a more efficient and effective model of care for knee osteoarthritis (OA). Therefore, the purpose of this study was to use pre-intervention gait kinematics and patient-reported outcome measures to predict post-intervention response to a 6-week hip strengthening exercise intervention in patients with mild-to-moderate knee OA.

Methods

Thirty-nine patients with mild-to-moderate knee osteoarthritis completed a 6-week hip-strengthening program and were subgrouped as Non-Responders, Low-Responders, or High-Responders following the intervention based on their change in Knee injury Osteoarthritis Outcome Score (KOOS). Predictors of responder subgroups were retrospectively determined from baseline patient-reported outcome measures and kinematic gait parameters in a discriminant analysis of principal components. A 3–4 year follow-up on 16 of the patients with knee OA was also done to examine long-term changes in these parameters.

Results

A unique combination of patient-reported outcome measures and kinematic factors was able to successfully subgroup patients with knee osteoarthritis with a cross-validated classification accuracy of 85.4%. Lower patient-reported function in daily living (ADL) scores and hip frontal plane kinematics during the loading response were most important in classifying High-Responders from other sub-groups, while a combination of hip, knee, ankle kinematics were used to classify Non-Responders from Low-Responders.

Conclusion

Patient-reported outcome measures and objective biomechanical gait data can be an effective method of predicting individual treatment success to an exercise intervention. Measuring gait kinematics, along with patient-reported outcome measures in a clinical setting can be useful in helping make evidence-based decisions regarding optimal treatment for patients with knee OA.

Intensive Gait Training for Older Adults with Symptomatic Knee Osteoarthritis

OBJECTIVE

The objective of this study was to determine whether individualized gait training is more effective than usual care for reducing mobility disability and pain in individuals with symptomatic knee osteoarthritis.

DESIGN

Adults aged 60 yrs or older with symptomatic knee osteoarthritis and mobility limitations were randomized to physical therapist-directed gait training on an instrumented treadmill, with biofeedback individualized to optimize knee movements, biweekly for 3 mos or usual care (control). Mobility disability was defined using Late Life Function and Disability Index Basic Lower Limb Function score (primary); mobility limitations, using timed 400-m walk, chair-stand, and stair-climb tests; and symptoms, using the Knee Injury/Osteoarthritis Outcome Score at baseline, as well as at 3, 6, and 12 mos. The analyses used longitudinal mixed models.

RESULTS

There were no significant intergroup differences between the 35 gait-training (74.3% women; age, 69.7 ± 8.2 yrs) and 21 control (57.1% women; age, 68.9 ± 6.5 yrs) participants at baseline. At 3 mos, the gait-training participants had greater improvement in mobility disability (4.3 ± 1.7; P = 0.0162) and symptoms (8.6 ± 4.1; P = 0.0420). However, there were no intergroup differences detected for pain, 400-m walk, chair-stand, or stair-climb times at 3 mos or for any outcomes at 6 or 12 mos.

CONCLUSIONS

Compared with usual care, individualized gait training resulted in immediate improvements in mobility disability knee symptoms in adults with symptomatic knee osteoarthritis, but these effects were not sustained.

Immediate and long-term efficacy of laterally-wedged insoles on persons with bilateral medial knee osteoarthritis during walking

Background

The current study aimed to investigate the immediate and long-term effects of laterally-wedged (LW) insoles on the knee loadings, the knee abductor moment (KAM) in particular, and the compensatory changes at other lower limb joints in patients with bilateral medial knee osteoarthritis during level walking with and without LW insoles.

Methods

Older adults with bilateral medial knee OA (age 66 ± 5.3 years; height 156 ± 4.9 cm; mass 60 ± 5.1 kg; leg length 83.72 ± 3.64 cm) were studied using computerized gait analysis initially (Baseline) and 6 weeks after using LW insoles (Follow-up) during barefoot walking and walking with LW insoles (7° of lateral inclination, with medial arch support). The three-dimensional angles and internal moments at the lower limb joints, as well as the ground reaction forces, were obtained using a motion analysis system and two forceplates. Key features of all the variables were compared using paired t tests for immediate effects (barefoot vs. LW) and for long-term effects (Baseline vs. Follow-up). The symptomatic severity (WOMAC Index) was also evaluated (Baseline vs. Follow-up).

Results

The KAM with LW insoles at Baseline was significantly reduced when compared to the barefoot condition (p < 0.05), suggesting that the LW insoles were effective in reducing unfavorable loadings at the knee immediately upon wearing the insoles. After 6 weeks of wearing LW insoles (Follow-up), no significant changes were found in most of the biomechanical variables, including KAM (p > 0.05), when compared to Baseline with LW insoles. However, a specific gait adaptation with reduced knee loading was revealed when walking without LW insoles, i.e., for the barefoot condition (p < 0.05).

Conclusions

After long-term use of LW insoles, the pain and physical function were improved with decreased peak KAM. A specific gait adaptation with reduced KAM was also found when walking without LW insoles. These results indicate a positive long-term effect in persons with bilateral medial knee OA, both as an orthosis to assist walking, and as a treatment intervention to facilitate gait adaptations in favor of reduced KAM.

Immediate effect of Masai Barefoot Technology shoes on knee joint moments in women with knee osteoarthritis

Footwear modification can beneficially alter knee loading in patients with knee osteoarthritis. This study evaluated the effect of Masai Barefoot Technology shoes on reductions in external knee moments in patients with knee osteoarthritis. Three-dimensional motion analysis was used to examine the effect of Masai Barefoot Technology versus control shoes on the knee adduction and flexion moments in 17 women (mean age, 63.6 years) with radiographically confirmed knee osteoarthritis. The lateral and anterior trunk lean values, knee flexion and adduction angles, and ground reaction force were also evaluated. The influence of the original walking pattern on the changes in knee moments with Masai Barefoot Technology shoes was evaluated. The knee flexion moment in early stance was significantly reduced while walking with the Masai Barefoot Technology shoes (0.25±0.14Nm/kgm) as compared with walking with control shoes (0.30±0.19 Nm/kgm); whereas the knee adduction moment showed no changes. Masai Barefoot Technology shoes did not increase compensatory lateral and anterior trunk lean. The degree of knee flexion moment in the original walking pattern with control shoes was correlated directly with its reduction when wearing Masai Barefoot Technology shoes by multiple linear regression analysis (adjusted R2=0.44, P<0.01). Masai Barefoot Technology shoes reduced the knee flexion moment during walking without increasing the compensatory trunk lean and may therefore reduce external knee loading in women with knee osteoarthritis.

Age-related differences in sagittal-plane knee function at heel-strike of walking are increased in osteoarthritic patients

OBJECTIVE

To compare age-related patterns of gait with patterns associated with knee osteoarthritis (OA), the following hypotheses were tested: (H1) The sagittal-plane knee function during walking is different between younger and older asymptomatic subjects; (H2) The age-related differences in H1 are increased in patients with knee OA.

DESIGN

Walking trials were collected for 110 participants (1.70 ± 0.09 m, 80 ± 14 kg). There were 29 younger asymptomatic subjects (29 ± 4 years) and 81 older participants (59 ± 9 years), that included 27 asymptomatic subjects and 28 and 26 patients with moderate and severe medial knee OA. Discrete variables characterizing sagittal-plane knee function were compared among the four groups using ANOVAs.

RESULTS

During the heel-strike portion of the gait cycle at preferred walking speed, the knee was less extended and the shank less inclined in the three older groups compared to the younger asymptomatic group. There were similar differences between the severe OA group and the older asymptomatic and moderate OA groups. Both OA groups also had the femur less posterior relative to the tibia and smaller extension moment than the younger group. During terminal stance, the severe OA group had the knee less extended and smaller knee extension moment than the younger asymptomatic and older moderate OA groups.

CONCLUSIONS

The differences in knee function, particularly those during heel-strike which were associated with both age and disease severity, could form a basis for looking at mechanical risk factors for initiation and progression of knee OA on a prospective basis.

Gait changes in individuals with bilateral hallux valgus reduce first metatarsophalangeal loading but increase knee abductor moments

Hallux valgus (HV), one of the most common foot pathologies in modern society, affects not only the foot itself, but also the other lower limb joints. The purpose of the study was to investigate the kinematic and kinetic changes in the lower limb joints in patients with bilateral HV during level walking. Twelve female patients with bilateral HV and 12 healthy female controls walked while three-dimensional kinematic and kinetic data were measured. Patients with HV were found to shift their center of pressure (COP) laterally away from the 1st metatarsophalangeal joint (MPJ), which helped unload the joint during late stance. The lateral shift of the COP in these patients was associated with the reduced toe-out angles of the foot as a result of increased internal rotation of the hip. However, this strategy increased the abductor moments at the knee, an index closely correlated with the medial load at the knee and a predictor of the onset and progression of medial OA. Early treatment of HV may be helpful not only for reducing foot pain and deformity, but also for preventing the potentially harmful loading at the knee, especially in those at risk of medial knee OA.

Knee moments after unicompartmental knee arthroplasty during stair ascent

BACKGROUND

For unicompartmental knee arthroplasty (UKA), abnormal loading on the tibiofemoral joint could exacerbate knee osteoarthritis or implant wear. Joint moments are an indirect measure of such loading. However, little is known about knee moments of patients with UKA, tempering enthusiasm for its use.

QUESTIONS/PURPOSES

In patients with UKAs performing stair ascent, we (1) determined whether interlimb differences for knee moments are demonstrated, (2) described the knee kinetics of patients with medial and lateral UKAs, and (3) investigated possible factors that might influence the knee abductor moments.

METHODS

In our cross-sectional study, we recruited 26 patients with UKA with nondiseased contralateral limbs who performed stair ascent. Seventeen patients had medial UKAs and nine had lateral UKAs. Paired t-tests and CIs were applied to determine interlimb differences within each UKA group for peak knee moments and times to peak moments.

RESULTS

During stair ascent, the medial UKA group displayed greater peak extensor moments for the nondiseased compared to the UKA limb (p = 0.030), whereas the lateral UKA group did not (p = 0.087). For both medial and lateral UKA groups, the UKA limb demonstrated greater internal peak abductor moments (p = 0.005 and 0.013, respectively). Both UKA groups exhibited knee moments similar to those in the literature. Limb dominance and postoperative time were correlated for both UKA groups.

CONCLUSIONS

Reduced knee extensor moments of limbs with UKA displayed by some participants may indicate less compressive loading on the tibiofemoral joint surfaces, whereas the increased abductor moments suggest increased compression on the medial compartment. These findings suggest UKA knees may not be subjected to excessive loads regardless of the side reconstructed.

Application of principal component analysis in clinical gait research: identification of systematic differences between healthy and medial knee-osteoarthritic gait

For a successful completion of a movement task the motor control system has to observe a multitude of internal constraints that govern the coordination of its segments. The purpose of this study was to apply principal component (PC) analysis to detect differences in the segmental coordination between healthy subjects and patients with medial knee osteoarthritis (OA). It was hypothesized that (1) systematic differences in patterns of whole body movement would be identifiable with this method even in small sample sized groups and that (2) these differences will include compensatory movements in the OA patients in both the lower and upper body segments. Marker positions and ground reaction forces of three gait trials of 5 healthy and 5 OA participants with full body marker sets were analyzed using a principal component analysis. Group differences in the PC-scores were determined for the first 10 PC-vectors and a linear combination of those PC-vectors where differences were found defined a discriminant vector. Projecting the original trials onto this discriminant vector yielded significant group differences (t(d=8)=3.011; p=0.017) with greater upper body movement in patients with knee OA that was correlated with the medial-lateral ground reaction force. These results help to characterize the adaptation of whole-body gait patterns to knee OA in a relatively small population and may provide an improved basis for the development of interventions to modify knee load. The PC-based motion analysis offered a highly sensitive approach to identify characteristic whole body patterns of movement associated with pathological gait.

Are mechanics different between male and female runners with patellofemoral pain?

INTRODUCTION

Patellofemoral pain (PFP) has often been attributed to abnormal hip and knee mechanics in females. To date, there have been few investigations of the hip and knee mechanics of males with PFP. The purpose of this study was to compare the lower extremity mechanics and alignment of male runners with PFP with healthy male runners and female runners with PFP. We hypothesized that males with PFP would move with greater varus knee mechanics compared with male controls and compared with females with PFP. Furthermore, it was hypothesized that males with PFP would demonstrate greater varus alignment.

METHODS

A gait and single-leg squat analysis was conducted on each group (18 runners per group). Measurement of each runner's tibial mechanical axis was also recorded. Motion data were processed using Visual 3D (C-Motion, Bethesda, MD). ANOVAs were used to analyze the data.

RESULTS

Males with PFP ran and squatted in greater peak knee adduction and demonstrated greater peak knee external adduction moment compared with healthy male controls. In addition, males with PFP ran and squatted with less peak hip adduction and greater peak knee adduction compared with females with PFP. The static measure of mechanical axis of the tibial was not different between groups. However, a post hoc analysis revealed that males with PFP ran with greater peak tibial segmental adduction.

CONCLUSION

Males with PFP demonstrated different mechanics during running and during a single-leg squat compared with females with PFP and with healthy males. Based upon the results of this study, therapies for PFP may need to be sex specific.

A theoretical framework for understanding neuromuscular response to lower extremity joint injury

Background:

Neuromuscular alterations are common following lower extremity joint injury and often lead to decreased function and disability. These neuromuscular alterations manifest in inhibition or abnormal facilitation of the uninjured musculature surrounding an injured joint. Unfortunately, these neural alterations are poorly understood, which may affect clinical recognition and treatment of these injuries. Understanding how these neural alterations affect physical function may be important for proper clinical management of lower extremity joint injuries.

Methods:

Pertinent articles focusing on neuromuscular consequences and treatment of knee and ankle injuries were collected from peer-reviewed sources available on the Web of Science and Medline databases from 1975 through 2010. A theoretical model to illustrate potential relationships between neural alterations and clinical impairments was constructed from the current literature.

Results:

Lower extremity joint injury affects upstream cortical and spinal reflexive excitability pathways as well as downstream muscle function and overall physical performance. Treatment targeting the central nervous system provides an alternate means of treating joint injury that may be effective for patients with neuromuscular alterations.

Conclusions:

Disability is common following joint injury. There is mounting evidence that alterations in the central nervous system may relate to clinical changes in biomechanics that may predispose patients to further injury, and novel clinical interventions that target neural alterations may improve therapeutic outcomes.

EFFECTS OF KNEE OSTEOARTHRITIS ON BODY'S CENTER OF MASS MOTION IN OLDER ADULTS DURING LEVEL WALKING

Knowledge of the control of the body's dynamic stability in patients with knee osteoarthritis (OA) is helpful for the management of these patients and for the evaluation of treatment outcomes. The purpose of the current study was to investigate the dynamic stability of patients with knee OA during level walking using variables describing the motion of the body's center of mass (COM) and its relationship to the center of pressure (COP). Kinematic and kinetic data during level walking were obtained from 10 patients with bilateral knee OA and 10 normal controls using a motion analysis system and two forceplates. Compared to the normal controls, patients with knee OA exhibited normal COM positions and velocities at key instances of gait but with significant changes in COM accelerations. In the sagittal plane, adjustments to the anterioposterior acceleration of the COM throughout the complete gait cycle were needed for better control of the COM during the more challenging latter half of single leg stance. Diminished A/P COM–COP separation was also used to maintain body stability with reduced joint loadings. In the frontal plane, this was achieved by increasing the acceleration of the body's COM towards the stance leg. The more jerky motion of the body's COM observed may be a result of reduced ability associated with knee OA in the control of the motion of the COM. Strengthening of the muscles of the lower extremities, as well as training of the control of the COM through a dynamic balance training program, are equally important for the dynamic stability of patients with knee OA.