A mathematical modelling study investigating the influence of knee joint flexion angle and extension moment on patellofemoral joint reaction force and stress

Effects of different sensory integration tasks on the biomechanical characteristics of the lower limb during walking in patients with patellofemoral pain

Purpose

This study aimed to analyze the biomechanical characteristics of the lower limb in patients with patellofemoral pain (PFP) while walking under different sensory integration tasks and elucidate the relationship between these biomechanical characteristics and patellofemoral joint stress (PFJS). Our study's findings may provide insights which could help to establish new approaches to treat and prevent PFP.

Method

Overall, 28 male university students presenting with PFP were enrolled in this study. The kinematic and kinetic data of the participants during walking were collected. The effects of different sensory integration tasks including baseline (BL), Tactile integration task (TIT), listening integration task (LIT), visual integration task (VIT) on the biomechanical characteristics of the lower limb were examined using a One-way repeated measures ANOVA. The relationship between the aforementioned biomechanical characteristics and PFJS was investigated using Pearson correlation analysis.

Results

The increased hip flexion angle (P = 0.016), increased knee extension moment (P = 0.047), decreased step length (P < 0.001), decreased knee flexion angle (P = 0.010), and decreased cadence (P < 0.001) exhibited by patients with PFP while performing a VIT were associated with increased patellofemoral joint stress. The reduced cadence (P < 0.050) achieved by patients with PFP when performing LIT were associated with increased patellofemoral joint stress.

Conclusion

VIT significantly influenced lower limb movement patterns during walking in patients with PFP. Specifically, the increased hip flexion angle, increased knee extension moment, decreased knee flexion angle, and decreased cadence resulting from this task may have increased PFJS and may have contributed to the recurrence of PFP. Similarly, patients with PFP often demonstrate a reduction in cadence when exposed to TIT and LIT. This may be the main trigger for increased PFJS under TIT and LIT.

The Immediate Biomechanical Effects of a Flat, Flexible School Shoe in Adolescents with Patellofemoral Pain

INTRODUCTION

Treatment options for adolescent patellofemoral pain (PFP) are limited. School footwear might be a suitable intervention to modulate patellofemoral joint (PFJ) loads in adolescents with PFP. This study examined the immediate effects of a flat, flexible school shoe compared with a traditional school shoe on knee joint kinematics and kinetics, and PFJ reaction force during walking and running in adolescents with PFP.

METHODS

A total of 28 adolescents (12 female, 16 male; mean ± SD age, 14.3 ± 1.7 yr) with PFP walked and ran on an instrumented treadmill in two randomly ordered conditions: (i) flat, flexible school shoe and (ii) traditional school shoe. Three-dimensional marker trajectory and ground reaction force data were sampled at 250 and 1000 Hz, respectively. Continuous ankle and knee joint angles and moments, PFJ reaction force, and ankle power were compared between conditions using one-dimensional statistical parametric mapping paired t -tests ( α < 0.05).

RESULTS

Walking in the flat, flexible school shoe resulted in a significant reduction in knee flexion (15%-35% of gait cycle, P < 0.001), knee extension moment (15%-40% of gait cycle, P < 0.001), and PFJ reaction force (15%-40% of gait cycle, P < 0.001) compared with the traditional school shoe. During running, knee flexion (10%-33% of gait cycle, P < 0.001), knee extension moment (15%-25% of gait cycle, P < 0.001), and PFJ reaction force (15%-25% of gait cycle, P < 0.001) were lower when wearing the flat, flexible school shoe compared with the traditional school shoe.

CONCLUSIONS

PFJ reaction force is reduced when adolescents walk and run in a flat, flexible school shoe compared with a traditional school shoe. Flat, flexible school shoes may be an effective intervention to modulate biomechanical factors related to PFP.

Gait biomechanics do not differ between adolescents with and without patellofemoral pain

OBJECTIVES

To determine if adolescents with patellofemoral pain exhibit different biomechanical characteristics to asymptomatic adolescents during walking and running.

METHODS

Twenty-eight adolescents with patellofemoral pain (16 male, 12 female, mean [SD] age: 14.3 [1.7] years) and 24 asymptomatic adolescents (13 male, 11 female, mean [SD] age: 14.1 [1.6] years) participated. Participants walked and ran on an instrumented treadmill in a standardized athletic shoe. Continuous hip, knee, and ankle joint angles and moments, and frontal plane pelvic motion were compared between groups using one-dimensional statistical parametric mapping independent t-tests (alpha <0.05). Cadence and stride length were compared between groups using independent t-tests.

RESULTS

During walking, adolescents with patellofemoral pain had a higher hip extension moment at 7%-8% of the gait cycle (p = 0.04) and walked with a shorter stride length (mean difference [95% confidence interval] = -0.07 [-0.1, -0.01] m). There were no other differences between groups during walking. During running, adolescents with patellofemoral pain had greater knee flexion than asymptomatic adolescents at 35%-40% of the gait cycle (p = 0.04) and ran with a higher cadence (mean difference [95% confidence interval] = 5.8 [2.0, 9.5] steps/min). There were no other statistically significant differences between groups during running.

CONCLUSIONS

Adolescents with patellofemoral pain demonstrate few biomechanical differences to asymptomatic adolescents during walking and running. The identified differences are likely of limited clinical importance. Biomechanical alterations which have been previously associated with patellofemoral pain in adults, may not need to be the target of management of adolescent patellofemoral pain.

Cartilage deformation following a walking bout in individuals with anterior cruciate ligament reconstruction

The purpose was to (1) compare the effect of a walking bout on femoral cartilage deformation between limbs with and without anterior cruciate ligament reconstruction (ACLR) and (2) examine the association between gait kinetics and the magnitude of cartilage deformation. A total of 30 individuals with primary unilateral ACLR completed this study [14 male, 16 female; age = 22.57 (3.78) years; body mass index (BMI) = 25.88 (5.68) kg/m2 ; time since ACLR = 61.00 (16.43) months]. Overground walking biomechanics were assessed on day 1, and a 30-min walking bout or 30-min resting bout (control) were completed on days 2 and 3 (counterbalanced order). Femoral cartilage thickness was measured using ultrasound before, immediately following, and 30-min following each intervention. Linear mixed effects models compared the effect of walking on cartilage thickness between the ACLR and contralateral limbs after adjusting for sex, BMI, speed, and the number of steps. Stepwise regression examined the association between the external knee flexion and adduction moments and cartilage deformation following walking. There was a significant limb × time interaction for medial cartilage thickness. Post hoc analyses indicated that cartilage thickness decreased immediately following walking in the contralateral but not ACLR limb. Main effects of limb were observed for medial, central, and lateral cartilage thickness indicating thicker cartilage in the ACLR compared with contralateral limb. A higher knee adduction moment was associated with greater cartilage deformation in the ACLR limb. Femoral cartilage in the ACLR limb exhibited a less dynamic response to walking than the uninvolved limb, which may be due to habitual underloading during gait.

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.

Simulated Tibiofemoral Joint Reaction Forces for Three Previously Studied Gait Modifications in Healthy Controls

Gait modifications, such as lateral trunk lean (LTL), medial knee thrust (MKT), and toe-in gait (TIG), are frequently investigated interventions used to slow the progression of knee osteoarthritis. The Lerner knee model was developed to estimate the tibiofemoral joint reaction forces (JRF) in the medial and lateral compartments during gait. These models may be useful for estimating the effects on the JRF in the knee as a result of gait modifications. We hypothesized that all gait modifications would decrease the JRF compared to normal gait. Twenty healthy individuals volunteered for this study (26.7 ± 4.7 years, 1.75 ± 0.1 m, 73.4 ± 12.4 kg). Ten trials were collected for normal gait as well as for the three gait modifications: LTL, MKT, and TIG. The data were used to estimate the JRF in the first and second peaks for the medial and lateral compartments of the knee via opensim using the Lerner knee model. No significant difference from baseline was found for the first peak in the medial compartment. There was a decrease in JRF in the medial compartment during the loading phase of gait for TIG (6.6%) and LTL (4.9%) and an increasing JRF for MKT (2.6%). but none was statistically significant. A significant increase from baseline was found for TIG (5.8%) in the medial second peak. We found a large variation in individual responses to gait interventions, which may help explain the lack of statistically significant results. Possible factors influencing these wide ranges of responses to gait modifications include static alignment and the impacts of variation in muscle coordination strategies used, by participants, to implement gait modifications.

The Effects of Cadence Manipulation on Joint Kinetic Patterns and Stride-to-Stride Kinetic Variability in Female Runners

Altering running cadence is commonly done to reduce the risk of running-related injury/reinjury. This study examined how altering running cadence affects joint kinetic patterns and stride-to-stride kinetic variability in uninjured female runners. Twenty-four uninjured female recreational runners ran on an instrumented treadmill with their typical running cadence and with a running cadence that was 7.5% higher and 7.5% lower than typical. Ground reaction force and kinematic data were recorded during each condition, and principal component analysis was used to capture the primary sources of variability from the sagittal plane hip, knee, and ankle moment time series. Runners exhibited a reduction in the magnitude of their knee extension moments when they increased their cadence and an increase in their knee extension moments when they lowered their cadence compared with when they ran with their typical cadence. They also exhibited greater stride-to-stride variability in the magnitude of their hip flexion moments and knee extension moments when they deviated from their typical running cadence (ie, running with either a higher or lower cadence). These differences suggest that runners could alter their cadence throughout a run in an attempt to limit overly repetitive localized tissue stresses.

The effect of heel-to-toe drop of running shoes on patellofemoral joint stress during running

BACKGROUND

Traditional running shoes with heel-to-toe drops is thought to be a contributor to increased patellofemoral joint stress, which is proposed as a mechanism of patellofemoral pain.

RESEARCH QUESTION

Is there an increase in patellofemoral joint stress when running in shoes with drops compared to running in shoes without a drop?

METHODS

Lower limbs kinematics and ground reaction force were collected from eighteen healthy runners during over-ground running in shoes with 15 mm, 10 mm, 5 mm drops, and without a drop. Patellofemoral joint force and stress were calculated from the kinematic and kinetic data using a biomechanical model of the patellofemoral joint.

RESULTS

The peak patellofemoral joint stress was increased by more than 15% when running in shoes with 15 mm and 10 mm drops compared to running in shoes without a drop (p = 0.003, p = 0.001). The knee flexion angle was significantly increased when running in shoes with 15 mm, 10 mm and 5 mm drops (p = 0.014, p = 0.003, p = 0.002), the knee extension moment (p = 0.009, p = 0.002) and patellofemoral joint force (p = 0.003, p = 0.001) were increased when running in shoes with 15 mm and 10 mm drops, compared to running in shoes without a drop.

SIGNIFICANCE

Compared to running in shoes without a drop, running in shoes with drops > 5 mm increase the peak patellofemoral joint stress significantly, which is mainly due to the increased knee extension moment.

Real-time visual feedback reduces patellofemoral joint forces during squatting in individuals with patellofemoral pain

BACKGROUND

Elevated patellofemoral joint forces appear to contribute to the development of patellofemoral pain. As a result, treatment of patellofemoral pain often includes movement retraining intended to reduce patellofemoral joint forces. Real-time visual feedback has been shown to be effective for retraining running kinematics; however, we are not aware of a previous study that has examined the influence of real-time visual feedback on patellofemoral joint mechanics during a squat.

METHODS

Twenty individuals with patellofemoral pain completed squats before (baseline) and immediately after (post-feedback) completing a real-time visual feedback training session. During the session, participants received visual feedback related to their patellofemoral joint forces (estimated via a musculoskeletal model) during squatting and were asked to alter their movement pattern to minimize these forces. Patellofemoral joint forces and hip, knee, and ankle joint mechanics were compared for the baseline and post-feedback trials in order to examine how feedback influenced squat performance.

FINDINGS

Participants demonstrated a 14.4% reduction in patellofemoral joint forces following the feedback session. They appeared to achieve this reduction in patellofemoral joint forces by squatting with less knee flexion (97.26 ± 17.11° vs. 102.96 ± 16.55°) and lower knee extension moments (0.10 ± 0.02 Nm/bodyweight vs. 0.11 ± 0.02 Nm/bodyweight) and quadriceps forces (4.06 ± 0.87 bodyweights vs. 4.67 ± 0.98 bodyweights).

INTERPRETATION

Real-time visual feedback appears to be effective for reducing patellofemoral joint forces during squatting in individuals with patellofemoral pain. As a result, training of this nature may be beneficial when treating patellofemoral pain.