Effects of sex and obesity on gait biomechanics before and six months after total knee arthroplasty: A longitudinal cohort study

The effect of body weight on the knee joint biomechanics based on subject-specific finite element-musculoskeletal approach

Knee osteoarthritis (OA) and obesity are major public health concerns that are closely intertwined. This intimate relationship was documented by considering obesity as the most significant preventable risk factor associated with knee OA. To date, however, the effects of obesity on the knee joint's passive-active structure and cartilage loading have been inconclusive. Hence, this study investigates the intricate relationship between obesity and knee OA, centering on the biomechanical changes in knee joint active and passive reactions during the stance phase of gait. Using a subject-specific musculoskeletal and finite element approach, muscle forces, ligament stresses, and articular cartilage contact stresses were analyzed among 60 individuals with different body mass indices (BMI) classified under healthy weight, overweight, and obese categories. Our predicted results showed that obesity significantly influenced knee joint mechanical reaction, increasing muscle activations, ligament loading, and articular cartilage contact stresses, particularly during key instances of the gait cycle-first and second peak loading instances. The study underscores the critical role of excessive body weight in exacerbating knee joint stress distribution and cartilage damage. Hence, the insights gained provide a valuable biomechanical perspective on the interaction between body weight and knee joint health, offering a clinical utility in assessing the risks associated with obesity and knee OA.

Long-term gait analysis in patients after total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Gait abnormalities have been described in patients after total knee arthroplasty (TKA), leading to the development of inter-joint coordination abnormalities and increased risk of falling. Such impairments have been reported to persist in the long-term, although the majority of studies assessed gait pattern especially in the first months after TKA.

RESEARCH QUESTION

What are the long-term gait impairments in patients after TKA compared to healthy age-matched subjects?

METHODS

A systematic search was conducted on MEDLINE/PubMed, EMBASE, CENTRAL and Scopus databases. Observational studies or randomized controlled trials investigating gait spatial-temporal, kinematic and kinetics parameters in a time-window longer than 6 months in patients with TKA compared to healthy age-matched subjects were included. Methodological quality was assessed using the modified Downs and Black (D&B) checklist and participants' characteristics, surgical procedures details and outcome measures were extracted. Pooled or un-pooled findings were categorized into "6 months - 1 year" and "more than 1 year" timepoint categories.

RESULTS

Twenty-eight studies (976 patients) were included. Overall quality was fair with a mean modified D&B score of 63.5 %. Reduced speed, stride length, cadence and longer stance phase were found in patients when compared to healthy individuals at "6 months - 1 year" follow-up. Spatial-temporal parameters deficits were also found at more than 1 year after TKA, where lower single-limb support and longer double-limb support durations were detected. These impairments occurred in concomitance with decreased knee range of motion along the sagittal and frontal planes and altered kinetic parameters. Hip kinematic and kinetic long-term impairments were also detected after TKA.

SIGNIFICANCE

These findings highlighted long-term gait pattern alterations in patients with TKA compared to age-matched healthy subjects. Future studies should identify interventions able to reduce long-term gait pattern alterations and improve function in patients after TKA.

Correlation dimension and entropy in the assessment of sex differences based on human gait data

Introduction

It is proved that there are differences between gait performed by females and males, which appear in movements of selected body parts. Despite numerous state-of-the-art studies related to the discriminative analysis of motion capture data, the question of whether measures of signal complexity and uncertainty can extract valuable features for the problem of sex distinction still remains open. It is the subject of the paper.

Methods

Correlation dimension, as well as approximate and sample entropies, are selected to describe motion data. In the numerical experiments, the collected dataset with 884 samples of 25 females and 30 males was used. The measurements took place in the Human Motion Laboratory (HML), equipped with a highly precise motion capture system. Two variants of data representation were investigated-time series that contain joint rotations of taken skeleton model as well as positions of the markers attached to the human body. Finally, a comparative analysis between the populations of females and males using descriptive statistics, non-parametric estimation, and statistical hypotheses verification was carried out.

Results

There are statistically significant sex differences extracted by the taken measures. In general, the movements of lower limbs result in greater values of correlation dimension and entropies for females, while selected upper body parts play a similar role for males. The dissimilarities are mainly observed in hip, ankle, shoulder, and head movements.

Discussion

Correlation dimension and entropy measures provide robust and explainable features of motion capture data with a valuable description of the human locomotion system. Thus, beyond the importance of discovered differences between females and males, their interpretation and understanding are also known.

Gait kinematics and knee stability 10-years following posterior-stabilised total knee arthroplasty comparable to healthy adults >55

PURPOSE

The purpose of this study was to compare the long-term objective biomechanical and functional parameters of a high-flexion total knee arthroplasty (TKA) design against healthy older adults to determine whether knee biomechanics are comparable in both populations.

METHODS

One cohort of patients with a primary TKA, and a cohort of healthy adults over 55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, and gait patterns were analysed with a three-dimensional-motion capture system. An arthrometer quantified the anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS software (α = 0.05).

RESULTS

Twenty-three knees were replaced in 20 patients. At 9.8 ± 3.1 years postoperatively, patients' knees had a statistically significantly poorer RoM than healthy controls' knees (n = 23) due to limited flexion; p < 0.0001. Patients also failed to achieve the same degree of knee flexion as controls during downhill gait. No kinematic differences were observed during mid-flexion in level nor downhill gait; a state that has been associated with instability (p = 0.614; not significant [n.s]). There were no differences between groups in knee laxity (n.s).

CONCLUSION

Patients in this study had similar gait patterns to healthy older adults during mid-flexion and were no more likely than the healthy controls to exhibit anterior-posterior translation of the knee > 7 mm; a known risk factor of instability. However, the knee flexion range was poorer. This likely led to bilateral pathological knee flexion patterns during downhill gait.

LEVEL OF EVIDENCE

Level III.

Influence of obesity on spatiotemporal gait parameters among female students from Jouf University, Saudi Arabia

Study aim: The aim of the current study is to explore the effect of obesity on spatiotemporal parameters of gait in obese young female students.

Material and methods: A cross-sectional study with fifteen obese female university students (mean age = 20.3 ± 1.6, mean BMI = 36.2 ± 4.6) and fifteen normal weight female university students (mean age = 20.9 ± 2, mean BMI = 22.6 ± 2.4) was conducted. The spatiotemporal gait parameters were evaluated using GAITRite® walkway (Frankline, USA, Model No. TR30RAM090 with software version 4.89C2).

Results: Independent sample t-test showed statistical significant differences in some spatiotemporal gait parameters between normal and obese subjects with statistically significant reductions of single-limb support time, step length, stride length, and velocity in the obese subjects rather than normal subjects (p = 0.031, 0.015, 0.039, and 0.002, respectively). Moreover, there were statistically significant increases of step time, stride time in the obese subjects rather than the normal subjects (p = 0.038, 0.017, respectively).

Conclusion: These results suggested that obesity is a factor that adversely affects the spatiotemporal gait parameters in the obese young female. This may be contributed to decrease the joints’ mobility and increase the incidence of joint osteoarthritis. So, it is recommended to encourage the sufficient physical activity and weight reduction among obese female students.

Radiographic analysis using the hip-to-calcaneus line and its association with lower limb joint kinetics in varus knee osteoarthritis

BACKGROUND

This study aimed to (1) determine whether the hip to ankle (HA) line or hip to calcaneus (HC) line better reflects knee coronal plane kinetics, (2) to examine whether the HC line reflects ankle coronal plane kinetics, and (3) to evaluate the radiological and biomechanical aspects of ankle in varus knee osteoarthritis (OA).

METHODS

Full-length, postero-anterior radiographs (hip-to-calcaneus radiographs) were taken and gait analysis was performed in 21 varus knee OA patients. The %HA where the HA lines pass through the tibial plateau, and the %HC and the mechanical ankle joint axis point (MAJAP), where the HC line passes through the tibial plateau and tibial plafond, respectively, were calculated. Knee adduction angular impulse (KAAI) and ankle inversion angular impulse (AIAI) were collected as kinetic data. Finally, we divided the patients into two groups with and without ankle OA, and compared each parameter between both groups.

RESULTS

The %HA and %HC were correlated with KAAI (%HA; r = -0.68, P = 0.001, %HC; r = -0.81, P < 0.001, respectively) and MAJAP was correlated with AIAI (r = -0.55, P = 0.009). MAJAP was significantly smaller, and KAAI and AIAI were significantly larger in the ankle OA group.

CONCLUSIONS

Radiographic analysis using the HC line was more strongly correlated to knee joint kinetics than the HA line and was also correlated to ankle joint kinetics. Assessing lower limb alignment using the HC line could be useful to evaluate the knee and ankle joints for varus knee OA.

Biomechanical Characteristics of the Knee Joint during Gait in Obese versus Normal Subjects

Knee osteoarthritis (OA) is a growing source of pain and disability. Obesity is the most important avoidable risk factor underlying knee OA. The processes by which obesity impacts osteoarthritis are of tremendous interest to osteoarthritis researchers and physicians, where the joint mechanical load is one of the pathways generally thought to cause or intensify the disease process. In the current work, we developed a hybrid framework that simultaneously incorporates a detailed finite element model of the knee joint within a musculoskeletal model to compute lower extremity muscle forces and knee joint stresses in normal-weight (N) and obese (OB) subjects during the stance phase gait. This model accounts for the synergy between the active musculature and passive structures. In comparing OB subjects and normal ones, forces significantly increased in all muscle groups at most instances of stance. Mainly, much higher activation was computed with lateral hamstrings and medial gastrocnemius. Cartilage contact average pressure was mostly supported by the medial plateau and increased by 22%, with a larger portion of the load transmitted via menisci. This medial compartment experienced larger relative movement and cartilage stresses in the normal subjects and continued to do so with a higher level in the obese subjects. Finally, the developed bioengineering frame and the examined parameters during this investigation might be useful clinically in evaluating the initiation and propagation of knee OA.

How to compare knee kinetics at different walking speeds?

BACKGROUND

Walking speed is a confounding factor in biomechanical analyses of gait, but still many studies compare gait biomechanics at comfortable walking speed (CWS) that is likely to differ between groups or conditions. To identify gait deviation unrelated to walking speed, methods are needed to correct biomechanical data over the gait cycle for walking speed.

RESEARCH QUESTION

How to compare knee kinetics over the gait cycle at different walking speeds?

METHODS

22 asymptomatic subjects walked on a dual-belt treadmill at CWS and 4 fixed speeds. Knee moments in sagittal (KFM) and frontal plane (KAM) were calculated via inverse dynamics. The net moment differences between CWS and fixed speed were expressed as a root-mean-square error (RMSE) normalized to the range of the variable. Two methods to correct for walking speed were compared. In method 1, KFM and KAM values were estimated based on interpolation between speeds at each percentage of the gait cycle. In method 2, principal component analysis was used to extract speed related features to reconstruct KFM and KAM at the speed of interest. The accuracy of both methods was tested using a leave-one-out cross validation.

RESULTS

Walking speed influenced the magnitude and shape of KFM and KAM. To account for these speed influences using both methods, leave-one-out cross validation showed low normalized RMSE (< 5 %), with little difference between the two methods. RMSE for both reconstruction methods were up to 60 % lower than the RMSE between CWS and fixed speed.

SIGNIFICANCE

Both methods could accurately correct knee kinetics over the gait cycle for the effects of walking speed. Walking speed dependency should be incorporated in each gait laboratory's reference dataset to be able to identify gait deviations unrelated to gait speed.

Gait mechanics are influenced by quadriceps strength, age, and sex after total knee arthroplasty

Although most patients are satisfied with outcomes after total knee arthroplasty (TKA), many retain preoperative altered gait mechanics. Identifying patient characteristics associated with gait mechanics will improve rehabilitation strategies and enhance our understanding of movement disorders. Therefore, the purpose of this study was to identify which patient characteristics are related to gait mechanics in the surgical limb during walking post-TKA. Patient characteristics included age, body mass, sex, quadriceps strength, self-reported function, and knee pain. General linear regression was used to compare patient characteristics associated with gait mechanics, after controlling for gait speed, functional capacity and time from surgery. We tested 191 patients cross-sectionally at 6-24 months after primary, unilateral TKA. Quadriceps weakness in the surgical limb was associated with less peak vertical ground reaction force (PvGRF) (β = .245, p = .044), knee extension moment (β = .283, p = .049), and knee extension excursion (β = .298, p = .038). Older age (β = .168, p = .050) was associated with less PvGRF. Quadriceps strength in the nonsurgical limb (β = -.357, p = .021) was associated with greater knee extension excursion in the surgical limb. Females with TKA (β = -.276, p = .007) had less knee flexion excursion compared to males. Faster gait speed was also associated with greater PvGRF (β = .585, p < .001), knee extensor moment (β = .481, p < .001), and knee flexion excursion (β = .318, p < .001). Statement of Clinical Significance: This study showed quadriceps weakness, slower gait speed, older age and being female were related to altered gait mechanics post-TKA. These findings will help clinicians better educate patients and develop targeted interventions for improving care in patients post-TKA.

Long-term functional symptoms after total knee arthroplasty

Background: The standard of the surgical treatment for arthrosis of the knee joint (KJ) at the later stages is total arthroplasty, which allows relieving the pain and eliminating the existing deformity. However, there are not enough data on the long-term results after the surgery that is important for understanding the dynamics of the recovery and predicting the result. Aims: Study of clinical, functional, and biomechanical symptoms in patients after total arthroplasty of the knee joint in the long-term period. Methods: 22 patients after knee joint replacement and 20 relatively healthy adults (control group) were examined in long-term periods. The biomechanics of walking was studied at an arbitrary pace. The temporal characteristics of the gait cycle, shock loads and movements in the hip joints (HJ) and KJ were recorded. We recorded the time characteristics of the walking cycle, shock loads and movements in the hip joint (HJ) and KJ. The patients were divided into two subgroups according to the results of the biomechanical study. The patients from subgroup 1 had good functionality with a swing amplitude of the knee joint of 50 degrees or more, the movement algorithm was preserved. The patients from subgroup 2 had a swing amplitude of up to 50 degrees, the movement algorithm was impaired. Results: The temporal characteristics of the waking cycle of knee arthroplasty patients did not differ significantly from the control group in the long term. Abduction-adduction and rotation movements in HJ and KJ show a decrease in the amplitudes, more pronounced in the second subgroup. The main changes in the kinematics of the hip joint are characterized by a decrease in the range of motion and a longer extension time during the support period, which was found for both sides, especially in the second subgroup. The greatest changes were observed in the kinematics of the knee joints movements. They included a decrease in the amplitude of all the movements, not only on the endoprosthesis side, but also on the opposite side. Conclusions: There is no complete restoration of the knee joint function after total arthroplasty in the long term. The function of both lower limbs is symmetrically decreased. The fact of functionally different (less severe and more severe) results may be associated with the initial functional state of the joint before arthroplasty or with the subsequent period of rehabilitation.

Matching walking speed of controls affects identification of gait deviations in patients with a total knee replacement

BACKGROUND

The assessment of functional recovery of patients after a total knee replacement includes the quantification of gait deviations. Comparisons to comfortable gait of healthy controls may incorrectly suggest biomechanical gait deviations, since the usually lower walking speed of patients already causes biomechanical differences. Moreover, taking peak values as parameter might not be sensitive to actual differences. Therefore, this study investigates the effect of matching walking speed and full-waveform versus discrete analyses.

METHODS

Gait biomechanics of 25 knee replacement patients were compared to 22 controls in two ways: uncorrected and corrected for walking speed employing principal component analyses, to reconstruct control gait biomechanics at walking speeds matched to the patients. Ankle, knee and hip kinematics and kinetics were compared over the full gait cycle using statistical parametric mapping against using peak values.

FINDINGS

All joint kinematics and kinetics gait data were impacted by applying walking speed correction, especially the kinetics of the knee. The lower control walking speeds used for reference generally reduced the magnitude of differences between patient and control gait, however some were enlarged. Full-waveform analysis identified greater deviating gait cycle regions beyond the peaks, but did not make peak value analyses redundant.

INTERPRETATION

Matching walking speed of controls affects identification of gait deviations in patients with a total knee replacement, reducing deviations confounded by walking speed and revealing hidden gait deviations related to possible compensations. Full-waveform analysis should be used along peak values for a comprehensive quantification of differences in gait biomechanics.

The influence of body mass index and sex on frontal and sagittal plane knee mechanics during walking in young adults

BACKGROUND

Obesity and female sex are independent risk factors for knee osteoarthritis and also influence gait mechanics. However, the interaction between obesity and sex on gait mechanics is unclear, which may have implications for tailored gait modification strategies.

RESEARCH QUESTION

The purpose of this study was to examine the influence of obesity and sex on sagittal and frontal plane knee mechanics during gait in young adults.

METHODS

Forty-eight individuals with (BMI = 33.03 ± 0.59; sex:50 % female; age:21.9 ± 2.6 years) and 48 without obesity (BMI:21.59 ± 0.25; sex:50 % female; age:22.9 ± 3.57 years) matched on age and sex completed over-ground gait assessments at a self-selected speed. Two (BMI) by two (sex) analysis of variance was used to compare knee biomechanics during the first half of stance in the sagittal (knee flexion moment [KFM] and excursion [KFE]) and frontal plane (first peak knee adduction moment [KAM], knee varus velocity [KVV]).

RESULTS

We observed a BMI by sex interaction for normalized KFM (P = 0.03). Females had smaller normalized KFM compared to males (P = 0.03), but only in individuals without obesity. Males without obesity had larger normalized KFM compared to males with obesity (P = 0.01), while females did not differ between BMI groups. We observed main effects of sex and BMI group, where females exhibited greater normalized KAM (P < 0.01) and KVV (P < 0.01) compared to males, and individuals with obesity walked with greater KVV compared to those without obesity (P < 0.01). All absolute joint moments were greater in individuals with obesity (all P<0.01) and males had greater absolute KFM compared to females (P < 0.01).

SIGNIFICANCE

We observed sex differences in gait mechanics, however, KFM differences between males and females were only evident in individuals without obesity. Further, females and individuals with obesity had a larger KAM and KVV, which may contribute to larger medial compartment joint loading.

Being Underweight Is Associated with Worse Surgical Outcomes of Total Knee Arthroplasty Compared to Normal Body Mass Index in Elderly Patients

Purpose

Being underweight has never been studied in relation to the radiologic and clinical outcomes of total knee arthroplasty (TKA) in elderly patients. The aim of this study was to determine the effect of being underweight on TKA radiological and clinical outcomes and to investigate whether being underweight influences postoperative complications compared to normal body mass index (BMI) in elderly patients.

Patients and Methods

A total of 118 female patients aged 65 years or older with BMI < 25 kg/m² who underwent primary TKA were divided into two groups based on BMI: group A: 18.5 kg/m² < BMI < 25 kg/m²; group B: BMI < 18.5 kg/m². The radiologic and clinical outcomes were evaluated at follow-up of 6, 12, and 24 months after surgery such as the hip-knee-ankle angle, the American Knee Society (AKS) score, Western Ontario and McMaster University score (WOMAC), and patellofemoral (PF) scale. Moreover, postoperative complications during follow-up were investigated.

Results

Preoperative clinical scores did not differ significantly between the two groups. Postoperative WOMAC pain (1.8 ± 1.9 versus 3.4 ± 2.6, p = 0.02), WOMAC function (12.4 ± 8.1 versus 16.5 ± 8.5, p = 0.012) and PF scales (26.1 ± 3.6 versus 23.7 ± 4.1, p = 0.002) were worse in the underweight group at 12 and 24 months after surgery. The frequency of postoperative complications did not differ significantly between groups. In multivariate linear regression analysis, underweight patient group was significantly associated with worse postoperative WOMAC and PF scores (p = 0.002, 0.005).

Conclusion

Although postoperative complications of TKA did not differ between groups, underweight patients had worse clinical outcomes of TKA compared to patients with normal BMI in elderly patients. Therefore, care should be taken when performing TKA in elderly underweight patients.

The influence of sex and pre-operative obesity on biomechanics two years after total knee arthroplasty: A longitudinal cohort study

BACKGROUND

Sex and obesity may influence knee biomechanics associated with poor outcomes following primary total knee arthroplasty (TKA) however their long-term impact has not been investigated.

RESEARCH QUESTION

Does sex and/or pre-operative obesity influence change in gait biomechanics from pre-TKA to two-years after TKA, and do knee biomechanics return to normal two-years after TKA?

METHODS

In this longitudinal study, gait analysis was performed on 78 patients undergoing TKA for knee osteoarthritis prior to surgery (baseline), and on 66 (85 %) of these who returned at the two year follow-up. Gait biomechanics were also collected on a reference sample of 40 asymptomatic participants. Knee variables were analyzed according to time (pre- and post-TKA), sex (men and women), pre-operative obesity (obese vs non-obese), and group (TKA vs reference). Mixed linear regression models were used to examine the effects of TKA, obesity status, gender and all interactions.

RESULTS

There were two-year reductions in peak knee frontal plane angle (mean difference -7.21°; 95% confidence intervals -9.37 to -5.05), peak knee adduction moment (KAM) (-17.64Nm; -23.04 to -12.24) and KAM impulse (-9.40Nm.s; -12.04 to -6.77) in males. These and other variables were unchanged in women. At two years, men exhibited a greater varus-valgus thrust excursion (4.9°; 2.7-7.2), and a lower peak knee frontal plane angle (-4.4°; -7.1 to -1.7) and peak KAM (-13.1Nm; -20.9 to -5.4), compared to the reference sample. Biomechanics at two years did not differ between pre-operative obesity subgroups, or between female TKA patients and the reference sample.

SIGNIFICANCE

Changes in gait biomechanics two years after TKA are influenced by sex but not obesity. Men but not women showed altered knee biomechanics two years following TKR and compared to a reference sample. It is unknown whether these altered biomechanics in men impact longer term clinical outcomes and satisfaction following surgery.