Contribution of knee adduction moment impulse to pain and disability in Japanese women with medial knee osteoarthritis

Functions and Effectiveness of Unloader, Patellofemoral, and Knee Sleeve Orthoses: A Review

Background

Knee orthoses have been extensively used as a nonsurgical approach to improving knee deficiencies. Currently, arthritic knee conditions remain the leading cause of disability, and this number is expected to increase. As the use of knee orthoses varies widely, so has their effectiveness which is still largely debatable. Here, we present the functions and effectiveness of the three most prominent knee orthotic models dedicated to supporting knee osteoarthritis-unloader, patellofemoral, and knee sleeves.

Purpose/Research Question

Considering the depth and diversity of the many clinical studies and documented laboratory reports published to date, this literature review was created to educate the clinician, patient, and researcher on common knee orthoses used for the management of arthritic knee conditions. In doing so, we discuss their design, biomechanical effects, and clinical efficacy, as well as broader outcomes, limitations, and recommendations for use.

Results/Synthesis

The knee orthoses discussed within the scope of this paper are dedicated to protecting the knee against strenuous compressive loads that may affect the patellofemoral and tibiofemoral joints of the knee. Since the knee has multiple axes of motion and articulating surfaces that experience different loads during functional activities, it can be implied that, to a large extent, knee brace designs can differ drastically. Unloader knee orthoses are designed to decrease tibiofemoral and patellofemoral joint pressures. Patellofemoral knee orthoses are designed to decrease strain on the patellofemoral and quadriceps tendons while stabilizing the patella. Knee sleeves are designed to stabilize movements, reduce pain in joints, and improve proprioception across the knee joint.

Conclusion

Although patients often report benefits from wearing braces, these benefits have not been confirmed by clinicians and scientific investigators. Results from these three orthosis types show that clinical efficacy is still elusive due to the different methodologies used by researchers.

Layman Summary

Knee orthoses also referred to as knee brace are commonly used for support and stability of the knee. Unloader knee braces are designed to relieve and support those suffering from knee osteoarthritis by improving physical impairment and reducing pain. Patellofemoral knee braces aim to help patients manage patellofemoral pain syndrome. Rehabilitative compression sleeves, also known as knee sleeves, are often used to assist patients suffering from knee pain and laxity. Important findings on the three knee braces discussed show discrepancies in results. Their effectiveness and validity are yet to be understood.

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis: A comparison of clinical and radiological outcomes

BACKGROUND

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis. However, which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much debate. Simultaneously, there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes, preoperatively and following HTO or UKA.

AIM

To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis: Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to this.

METHODS

This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n = 23) and HTO (n = 19) to treat medial compartment knee osteoarthritis. Patient-reported outcome measures (PROMs) were collected to evaluate clinical outcome. These included two disease-specific (Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score) and two generic (EQ-5D-5L, Short Form-12) PROMs. The radiographic parameters of knee alignment assessed were the: Hip-knee-ankle angle, mechanical axis deviation and angle of Mikulicz line.

RESULTS

Statistical analyses demonstrated significant (P < 0.001), preoperative to postoperative, improvements in the PROM scores of both groups. There were, however, no significant inter-group differences in the postoperative PROM scores of the UKA and HTO group. Several significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively (P < 0.05). Postoperatively, two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters (hip-knee-ankle angle, mechanical axis deviation) within the HTO group; yet no such associations were observed within the UKA group.

CONCLUSION

UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with medial compartment knee osteoarthritis. Clinical outcome has a limited association with radiographic parameters of knee joint alignment postoperatively; however, a more distolaterally angled Mikulicz line appears associated with worse knee function/health-related quality of life preoperatively.

Understanding muscle coordination during gait based on muscle synergy and its association with symptoms in patients with knee osteoarthritis

OBJECTIVE

We aimed to investigate the muscle coordination differences between a control group and patients with mild and severe knee osteoarthritis (KOA) using muscle synergy analysis and determine whether muscle coordination was associated with symptoms of KOA.

METHOD

Fifty-three women with medial KOA and 19 control patients participated in the study. The gait analyses and muscle activity measurements of seven lower limb muscles were assessed using a motion capture system and electromyography. Gait speed and knee adduction moment impulse were calculated. The spatiotemporal components of muscle synergy were extracted using non-negative matrix factorization, and the dynamic motor control index during walking (walk-DMC) was computed. The number of muscle synergy and their spatiotemporal components were compared among the mild KOA, severe KOA, and control groups. Moreover, the association between KOA symptoms with walk-DMC and other gait parameters was evaluated using multi-linear regression analysis.

RESULTS

The number of muscle synergies was lower in mild and severe KOA compared with those in the control group. In synergy 1, the weightings of biceps femoris and gluteus medius in severe KOA were higher than that in the control group. In synergy 3, the weightings of higher tibial anterior and lower gastrocnemius lateralis were confirmed in the mild KOA group. Regression analysis showed that the walk-DMC was independently associated with knee-related symptoms of KOA after adjusting for the covariates.

CONCLUSIONS

Muscle coordination was altered in patients with KOA. The correlation between muscle coordination and KOA may be attributed to the knee-related symptoms. Key points • Patients with knee osteoarthritis (OA) experienced a deterioration in muscle coordination when walking. • Loss of muscle coordination was associated with severe knee-related symptoms in knee OA. • Considering muscle coordination as a knee OA symptom-related factor may provide improved treatment.

The relationship between knee flexion excursion and mechanical stress during gait in medial knee osteoarthritis

BACKGROUND

A decrease in knee flexion excursion during the loading response may affect not only quadriceps muscle weakness, pain, and inflammatory symptoms, but also lead to physical function decline and activity limitation. The aim of this investigation was to clarify the relationship between knee flexion excursion during the loading response and mechanical stress on the knee joint, muscle strength, pain, and physical function in patients with knee osteoarthritis.

METHODS

Twenty patients diagnosed with medial knee osteoarthritis. The participants walked along a 10 m corridor in the laboratory at a comfortable pace. The kinematic and kinetic data were collected using a 3D motion analysis system. We employed to control for gait speed and age while examining the relationship between knee flexion excursion during the loading response and mechanical stress on the knee joint, muscle strength, pain, and physical function.

FINDINGS

Knee flexion excursion showed a significant positive correlation with the peak and angular impulse of knee flexion moment. In the partial correlation coefficients controlling for age and gait speed, significant negative correlations were found between knee flexion excursion and knee adduction moment angular impulse.

INTERPRETATION

It can be inferred that gait with reduced knee flexion movement during the loading response in patients with knee osteoarthritis may result in increased mechanical stress on the knee joint in the frontal plane. Exercise interventions aimed at increasing knee flexion excursion may result in a reduction in disease progression.

Neuropathic-like pain in knee osteoarthritis: exploring differences in knee loading and inflammation. A cross-sectional study

BACKGROUND

A subgroup of patients with knee osteoarthritis (OA) reports symptoms attributable to a neuropathic cause. Little to no attention has been invested on investigating differences in knee loading and inflammation in these patients.

AIM

To explore differences in inflammation and knee loading in patients with knee OA categorized based on the presence of neuropathic-like pain.

DESIGN

Cross-sectional study.

SETTING

Ghent University Hospital, Ghent, Belgium.

POPULATION

Knee OA patients.

METHODS

cross-sectional analysis of data from 96 patients (mean age 64.18±7.11 years) with primary knee OA participating in a randomized controlled trial. Participants were divided into three groups (unlikely, possible and indication of neuropathic-like pain) according to the modified painDETECT questionnaire (mPDQ). Data on demographics, symptoms and physical function were obtained by questionnaires. Effusion/synovitis and bone marrow lesions (BMLs) were measured using magnetic resonance imaging. Knee loading variables (knee adduction moment [KAM], KAM impulse, and knee flexion moment [KFM]) were assessed by 3D-motion analysis. One-way analysis of covariance (ANCOVA), Chi-square test and curve analyses were used to analyze continuous, categorical and loading variables respectively. Multinomial logistic regression was used to identify predictors for neuropathic-like pain.

RESULTS

Patients with indication of neuropathic-like pain exhibited higher KAM impulse compared to those with no indication of neuropathic-like pain (standard mean difference (SMD): -0.036 Nm normalized to body weight and height per second, 95% CI: -0.071, -0.001) along with greater pain intensity (SMD: 3.87 units, 95% CI: 1.90, 5.84), stiffness (SMD: 1.34 units, 95% CI: 0.19, 2.48) and worse physical function (SMD: 13.98 units 95% CI: 7.52, 20.44). Curve analysis showed no significant differences in KFM and KAM between groups. Effusion/synovitis and BMLs did not differ significantly between groups. The best predictors for indication of neuropathic-like pain were KAM impulse, Hoffa and sex.

CONCLUSIONS

Knee OA patients with indication of neuropathic-like pain exhibited higher dynamic medial loading, greater pain severity and worse physical function, while inflammatory markers were not significantly different across mPDQ groups. Future longitudinal studies are warranted to strengthen the evidence and establish mechanisms to explain associations between neuropathic-like pain and knee loading.

CLINICAL REHABILITATION IMPACT

Knee loading is a modifiable factor and patients with neuropathic-like pain may benefit from offloading interventions.

Relationship between ankle-foot-complex mobility during static loading and frontal moment impulses of knee and hip joints during the stance phase

BACKGROUND

Ankle-foot-complex mobility impairments, which can be assessed by the difference between the sitting and standing positions, are related to an increase in the load on the knee and hip joints during the stance phase of the gait.

RESEARCH QUESTION

What is the relationship between the ankle-foot-complex mobility during static weight bearing and the mechanical stresses on the knee and hip joints throughout the stance phase?

METHODS

Ankle-foot-complex mobility and gait data were collected from 26 healthy adults. The complex mobility was established by comparing the foot indices, measured using a three-dimensional foot scanner, in sitting and standing positions. The gait data were acquired using eight cameras (recording at 100 Hz) and three force plates (recording at 1000 Hz). Stance phase data were collected via ground reaction forces. The stance phase was dissected into shock absorption and propulsion phases, during which the external knee and hip adduction moment impulses (KAMi, HAMi) were recorded. The correlation between the ankle-foot-complex mobility during static weight bearing and KAMi and HAMi during the stance phase was examined using Pearson's product-moment correlation coefficients.

RESULTS

This study revealed that KAMi correlated with medial malleolus mobility (r = -0.44) throughout the stance phase. Furthermore, in the propulsive phase, KAMi correlated with calcaneus (r = 0.51) and navicular (r = -0.50) mobilities, whereas HAMi correlated with calcaneus mobility (r = -0.40).

SIGNIFICANCE

The study provides insights into the relationship between the static mobility of the ankle-foot complex in healthy individuals and mechanical stress during the stance phase. Calcaneus and navicular mobilities were related to efficient push-off in the propulsive phase. Medial malleolus mobility was related to the control of the lateral tilt of the lower limb and ankle dorsiflexion motion throughout the stance phase.

Impact of pronated foot on energetic behavior and efficiency during walking

BACKGROUND

The longitudinal arch of the foot acts like a spring during stance and contributes to walking efficiency. Pronated foot characterized by a collapsed medial longitudinal arch may have the impaired spring-like function and poor walking efficiency. However, the differences in the energetic behavior during walking between individuals with pronated foot and neutral foot have not been considered.

RESEARCH QUESTION

How does the energetic behavior within the foot and proximal lower limb joints in pronated foot affect walking efficiency?

METHODS

Twenty-one healthy young adults were classified into neutral foot and pronated foot based on the Foot Posture Index score. All subjects walked across the floor and attempted to have the rearfoot and forefoot segments contact separate force plates to analyze the forces acting on isolated regions within the foot. Kinematic and kinetic data were recorded by a three-dimensional motion capture system. The hip, knee, ankle, and mid-tarsal joint power was quantified using a 6-degree-of-freedom joint power method. To qualify total power within all structures of the foot and forefoot, we used a unified deformable segment analysis. Additionally, we calculated the center of mass power to quantify the total power of the whole body RESULTS: There is no difference in the mid-tarsal joint work between the pronated foot and neutral foot. On the other hand, pronated foot exhibited greater net negative work at structures distal to the forefoot during walking. Additionally, pronated foot exhibited less net positive work at the ankle and center of mass during walking compared to neutral foot.

SIGNIFICANCE

Individuals with pronated foot generate the mid-tarsal joint work by increasing the work absorbed at structures distal to the forefoot, which results in reduced energy efficiency during walking. That energy inefficiency may reduce positive work at the ankle and affect the walking efficiency in individuals with pronated foot.

Hip adduction angle during wider step-width gait affects hip adduction moment impulse

BACKGROUND

Decreasing an external hip adduction moment (HAM) impulse during stance is important to prevent the progression of hip osteoarthritis. A hip adduction angle (HAA) during walking influences the HAM impulse. Although a wider step-width (WS) gait is a gait modification to decrease a peak HAM, no study has reported the HAM impulse and HAA.

RESEARCH QUESTION

We investigated whether the HAA influences the peak HAM and HAM impulse during WS gait.

METHODS

Twenty-six healthy young adults walked with normal step-width (NS) and WS comfortably. They were not instructed about hip adduction motion during gait, and the peak HAM, HAM impulse, HAA, and other gait parameters were evaluated using a 3D motion capture system. The participants were divided into two groups according to the HAA size during WS gait. The percentage reduction of HAM variables (the WS condition relative to the NS condition) and other gait parameters were compared between the groups.

RESULTS

No difference in gait parameters was found between the groups. The percentage reduction of the HAM impulse in participants with smaller HAA was significantly higher than that in participants with larger HAA (14.5 % vs. 1.6 %, p < 0.01). Also, during normal step-width gait, the large HAA group showed a significantly larger HAA compared to the small HAA group (about 3°).

SIGNIFICANCE

Participants with smaller HAA could decrease the HAM impulse more effectively during WS gait compared with those with larger HAA. Thus, the HAA would influence the HAM impulse reduction effect on the WS gait. We recommend paying attention to the HAA to decrease the HAM with the WS gait.

Verification of biomechanical factors of gait related to medial knee loading in patients 6 Months after total knee arthroplasty

Background

The knee adduction moment (KAM) is considered an index for estimating the knee mechanical load, and increased KAM peak and KAM impulse are related to increased medial knee load and progression of knee joint degeneration. We aimed to verify the biomechanical factors of gait related to medial knee loading in patients 6 months after TKA.

Methods

Thirty-nine women who underwent TKA were enrolled. A three-dimensional gait analysis was performed 6 months postoperatively to generate data on the lower limb joint angle, moment, and power at the backward component (braking phase) and forward component (propulsion phase) peaks of the ground reaction force. Medial knee loading was evaluated using the time-integrated value of KAM during the stance period (KAM impulse). The higher the value of the KAM impulse, the higher the medial knee joint load. The relationships between the KAM impulse and the data for biomechanical factors were evaluated using partial correlation analysis with gait speed as a control factor.

Results

In the braking phase, the KAM impulse positively correlated with the knee adduction angle (r = 0.377) and negatively correlated with the toe-out angle (r = -0.355). The KAM impulse positively correlated with the knee adduction angle (r = 0.402), the hip flexion moment (r = 0.335), and the hip adduction moment (r = 0.565) and negatively correlated with the toe-out angle (r = -0.357) in the propulsive phase.

Conclusion

The KAM impulse 6 months after TKA was related to the knee adduction angle, hip flexion moment, hip adduction moment, and toe-out angle. These findings may provide fundamental data for controlling variable medial knee joint load after TKA and implementing patient management strategies to ensure implant durability.

Spinopelvic fusion surgery from lower thoracic spine to pelvis increased hip joint moment-motion analysis

PURPOSE

Spinal fusion surgery is often performed with pelvic fixation to prevent distal junctional kyphosis. The inclusion of spinopelvic fixation has been reported to induce progression of hip joint arthropathy in a radiographic follow-up study. However, its biomechanical mechanism has not yet been elucidated. This study aimed to compare the changes in hip joint moment before and after spinal fusion surgery.

METHODS

This study was an observational study and included nine patients (eight women and one man) who were scheduled to undergo spinopelvic fusion surgery. We calculated the three-dimensional external joint moments of the hip during gait, standing, and climbing stairs before and 1 year after surgery.

RESULTS

During gait, the maximum extension moment was 0.51 ± 0.29 and 0.63 ± 0.40 before and after spinopelvic fusion surgery (p = 0.011), and maximum abduction moment was 0.60 ± 0.33 and 0.83 ± 0.34 before and after surgery (p = 0.004), respectively. During standing, maximum extension moment was 0.76 ± 0.32 and 1.04 ± 0.21 before and after spinopelvic fusion surgery (p = 0.0026), and maximum abduction moment was 0.12 ± 0.20 and 0.36 ± 0.22 before and after surgery (p = 0.0005), respectively. During climbing stairs, maximum extension moment was - 0.31 ± 0.30 and - 0.48 ± 0.15 before and after spinopelvic fusion surgery (p = 0.040), and maximum abduction moment was 0.023 ± 0.18 and - 0.02 ± 0.13 before and after surgery (p = 0.038), respectively.

CONCLUSION

This study revealed that hip joint flexion-extension and abduction-adduction moments increased after spinopelvic fixation surgery in the postures of standing, walking, and climbing stairs. The mechanism was considered to be adjacent joint disease after spinopelvic fusion surgery including sacroiliac joint fixation.

Early Changes in Postural Balance Following Inverted V-Shaped High Tibial Osteotomy in Patients With Knee Osteoarthritis

Patients with knee osteoarthritis and varus knee deformity have impaired postural balance, resulting in decreased walking performance and an increased risk of falls. This study aimed to investigate the early changes in the postural balance following inverted V-shaped high tibial osteotomy (HTO). Fifteen patients with medial knee osteoarthritis were recruited. Postural balance was assessed using the center-of-pressure (COP) data during single-leg standing before and 6 weeks after inverted V-shaped HTO. The maximum range, mean velocity, and area of COP movements in the anteroposterior and mediolateral directions were analyzed. Preoperative and postoperative visual analog scale for knee pain was assessed. The maximum range of COP in the mediolateral direction decreased (P = .017), whereas the mean velocity of COP in the anteroposterior direction increased 6 weeks postoperatively (P = .011). The visual analog scale score for knee pain significantly improved at 6 weeks postoperatively (P = .006). Valgus correction with inverted V-shaped HTO resulted in improved postural balance in the mediolateral direction and good short-term clinical outcomes early following surgery. Early rehabilitation after inverted V-shaped HTO should focus on postural balance in the anteroposterior direction.

Relationship Between Knee Biomechanics and Pain in People With Knee Osteoarthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

Our primary aim was to determine the cross-sectional relationship between knee biomechanics during gait and pain in people with medial knee osteoarthritis. Our secondary aim was to evaluate differences in knee biomechanics between symptomatic and asymptomatic participants with medial knee osteoarthritis.

METHODS

Four online databases were searched from inception to July 2021. Eligible studies included people with medial/nonspecific knee osteoarthritis and a reported relationship between knee biomechanics during gait and pain or biomechanics of symptomatic and asymptomatic participants. Two reviewers independently extracted data and evaluated risk of bias. Random-effects meta-analyses were performed when three or more studies reported the same biomechanical variable for pooling (knee adduction moment [KAM], KAM impulse, varus thrust, and peak knee flexion moment [KFM]).

RESULTS

Forty studies were included. Methodological quality ranged from 4 to 9/10. Forty-seven unique biomechanical variables were reported. For the KAM, there was no correlation with pain for peak values pooled (early stance and overall) (r = 0.00, 95% confidence interval [95% CI]: -0.12, 0.11, k = 16), a small negative correlation for early stance peak alone (r = -0.09, 95% CI -0.18, -0.002, k = 12), and a medium positive correlation for the overall peak during stance (r = 0.30, 95% CI 0.17, 0.42, k = 4). Metaregression identified that body mass index moderated the peak KAM-pain relationship (P < 0.001). KAM impulse had a small positive correlation with pain (r = 0.23, 95% CI 0.04, 0.40, k = 5), and people with varus thrust had 3.84 greater odds of reporting pain compared with people without (95% CI 1.72, 8.53, k = 3). Meta-analyses for the peak KFM and pain correlation and secondary aim were nonsignificant.

CONCLUSION

Some knee gait biomechanics were associated with pain in this cohort. Longitudinal studies are required to determine causality.

Predicting knee adduction moment response to gait retraining with minimal clinical data

Knee osteoarthritis is a progressive disease mediated by high joint loads. Foot progression angle modifications that reduce the knee adduction moment (KAM), a surrogate of knee loading, have demonstrated efficacy in alleviating pain and improving function. Although changes to the foot progression angle are overall beneficial, KAM reductions are not consistent across patients. Moreover, customized interventions are time-consuming and require instrumentation not commonly available in the clinic. We present a regression model that uses minimal clinical data—a set of six features easily obtained in the clinic—to predict the extent of first peak KAM reduction after toe-in gait retraining. For such a model to generalize, the training data must be large and variable. Given the lack of large public datasets that contain different gaits for the same patient, we generated this dataset synthetically. Insights learned from a ground-truth dataset with both baseline and toe-in gait trials (N = 12) enabled the creation of a large (N = 138) synthetic dataset for training the predictive model. On a test set of data collected by a separate research group (N = 15), the first peak KAM reduction was predicted with a mean absolute error of 0.134% body weight * height (%BW*HT). This error is smaller than the standard deviation of the first peak KAM during baseline walking averaged across test subjects (0.306%BW*HT). This work demonstrates the feasibility of training predictive models with synthetic data and provides clinicians with a new tool to predict the outcome of patient-specific gait retraining without requiring gait lab instrumentation.

Gait retraining is a conservative intervention for knee osteoarthritis shown to reduce pain and improve function. Although customizing a treatment plan for each patient results in a better therapeutic response, customization cannot yet be performed outside of the gait laboratory, preventing research advances from becoming part of clinical practice. Our work aimed to build a model that accurately predicts whether a patient with knee osteoarthritis will benefit from non-invasive gait retraining using measures that can be easily collected in the clinic. To overcome the lack of large datasets required to train predictive models, we generated data synthetically (N = 138) based on limited ground-truth examples, and we provide experimental evidence for the model’s ability to generalize to real data (N = 15). Our results contribute toward a future in which clinicians can use data collected in the clinic to easily identify patients who would respond to therapeutic gait retraining.

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.

IMMEDIATE EFFECTS OF SEMI-CUSTOM INSOLES AND STRUCTURED KNEE SLEEVES ON LOWER EXTREMITY KINETICS AND KINEMATICS IN RECREATIONAL MALE ATHLETES WITH PATELLOFEMORAL PAIN

The aim of this experiment was to provide insight into the immediate influence of both semi-custom insoles and knee sleeves in recreational male runners/athletes suffering from patellofemoral pain and also to explore the association between the extent of patellofemoral pain and psychological wellbeing. Experiment 1 examined 17 male recreational runners with patellofemoral pain, in semi-custom insole and no-insole conditions. Experiment 2 examined 13 male recreational athletes with patellofemoral pain, undertaking run, [Formula: see text] cut and single-leg hop movements in knee sleeve and no-sleeve conditions. In both experiments, motion capture and ground reaction forces were collected, allowing kinetics and three-dimensional kinematics to be calculated alongside patellofemoral joint loading quantified using musculoskeletal modeling. In both experiments, patellofemoral pain symptoms were examined using the KOOS patellofemoral pain subscale and psychological wellbeing using the COOP-WONCA questionnaire. The findings from both experiments showed that pain symptoms significantly predicted psychological wellbeing ([Formula: see text] in experiment 1 and [Formula: see text] in experiment 2). Experiment 1 showed that orthoses significantly reduced tibial internal rotation range of motion (no-[Formula: see text] and [Formula: see text]) whilst also increasing the peak knee adduction moment (no-[Formula: see text][Formula: see text]N[Formula: see text]m/kg and [Formula: see text][Formula: see text]N[Formula: see text]m/kg). The findings from experiment 2 revealed that the knee sleeve reduced the peak patellofemoral force (no-[Formula: see text][Formula: see text]BW and [Formula: see text][Formula: see text]BW) in the run movement and the patellofemoral load rate in the cut movement (no-[Formula: see text][Formula: see text]BW/s and [Formula: see text][Formula: see text]BW/s). Overall, the findings confirm that pain symptoms are predictive of psychological wellbeing in recreational male athletes with patellofemoral pain. Furthermore, the findings suggest that both insoles and knee sleeves may provide immediate biomechanical benefits in recreationally active individuals with patellofemoral pain, although when wearing insoles this may be at the expense of an increased knee adduction moment during running.

Relationship between radiographic measurements and knee adduction moment using 3D gait analysis

BACKGROUND

Radiographic factors estimate the state of the static knee joint, and it is questionable how well these parameters reflect the dynamic knee condition. The external knee adduction moment (KAM) during gait is known to be a kinetic variable contributing to osteoarthritis progression. This study aims to investigate the effects of static radiographic parameters on the dynamic KAM during gait.

METHODS

Overall, 123 patients (mean age, 65.7 years; standard deviation, 8.1 years; 34 men and 89 women) were included. Seven radiographic parameters including the mechanical tibiofemoral angle (mTFA), Kellgren-Lawrence grade, and ankle joint line orientation (AJLO) were measured on radiographs, and the maximum KAM and KAM-time integral in the stance phase were obtained using three-dimensional gait analysis. The correlation and multiple regression analyses were performed for identifying significant radiographic measurements associated with the KAM.

RESULTS

Most of the radiographic measurements correlated with the maximum KAM and KAM-time integral. As a result of multiple regression analysis, the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as significant factors associated with the KAM-time integral (R² = 0.450); the mTFA (p < 0.001) and AJLO (p = 0.003) were identified as a significant factor associated with the maximum KAM (R² = 0.352) in multiple regression analysis. The discriminant validity of KAM was highest at varus 5.7 degree of the mTFA and 7.5 degree of the AJLO.

SIGNIFICANCE

The mTFA and AJLO were significantly associated with the KAM. However, to be used as a surgical indication for corrective osteotomy, a longitudinal study is needed to validate whether the mTFA and AJLO values directly cause osteoarthritis progression as we have suggested.

LEVEL OF EVIDENCE

III.

Association between changes in the knee adduction moment and changes in knee pain and function in response to non-surgical biomechanical interventions for medial knee osteoarthritis: a systematic review

There is lack of understanding of the relationship between knee adduction moment (KAM) reductions and improvements in pain or function in patients with knee osteoarthritis (KOA). Moreover, there is no systematic review describing the longitudinal relationship between KAM changes and subsequent changes in pain and/or physical function. We aimed (1) to investigate the relationship between changes in KAM induced by non-surgical biomechanical interventions and consecutive changes in pain and/or physical function in patients with medial KOA and (2) to compare this relationship for different interventions. We considered eligible all RCTs using biomechanical interventions aimed to reduce KAM in KOA patients, that measured pain/function. We used Cohen's d effect size to quantify outcome measurements. 14 papers reporting 11 studies were identified. Braces were tested in 6 studies, insoles in 5 studies, shoes in 3 studies and gait retraining in 2 studies. Methodological differences were large among studies. Large effect sizes (≥0.8) changes in pain/function were observed with interventions having at least a small KAM effect size (≥0.2), suggesting an association between KAM and pain/function changes. A linear trend was observed between inter-intervention KAM and VAS pain effect sizes, based on 4 studies. No firm conclusions could be drawn for the different intervention types. There was a trend toward larger KAM reductions leading to larger improvements in pain/function in non-surgical biomechanical interventions. Additional high-quality RCT with consistent methodology are needed to fully characterize the association between KAM and pain/function changes.

Effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase

Background

An excessive daily cumulative hip moment in the frontal plane (determined as the product of hip moment impulse in the frontal plane during the stance phase and mean number of steps per day) is a risk factor for the progression of hip osteoarthritis. Moreover, walking speed and step length decrease, whereas cadence increases in patients with hip osteoarthritis. However, the effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase are not known. Therefore, this study aimed to examine the effects of step length and cadence on hip moment impulse in the frontal plane during the stance phase.

Methods

We used a public dataset (kinetic and kinematic data) of over-ground walking and selected 31 participants randomly from the full dataset of 57 participants. The selected participants walked at a self-selected speed and repeated the exercise 15 times. We analyzed the data for all 15 trials for each participant. Multiple regression analysis was performed with the hip moment impulse in the frontal plane during the stance phase as the dependent variable and step length and cadence as independent variables.

Results

The adjusted R² in this model was 0.71 (p < 0.001). The standardized partial regression coefficients of step length and cadence were 0.63 (t = 5.24; p < 0.001) and −0.60 (t =  − 4.58; p < 0.001), respectively.

Conclusions

Our results suggest that low cadence, not short step length, increases the hip moment impulse in the frontal plane. Our findings help understand the gait pattern with low hip moment impulse in the frontal plane.

Dynamic postural control correlates with activities of daily living and quality of life in patients with knee osteoarthritis

Background

Knee osteoarthritis (OA) negatively affects dynamic postural control, which is a basic function that individuals use to perform activities of daily living (ADL). The purpose of this study was to investigate the associations of center of pressure (COP) control during the transition from double-leg to single-leg standing with subjective assessments of ADL and quality of life (QOL) in patients with knee OA.

Methods

Thirty-six patients (29 females) with moderate-to-severe knee OA participated. Dynamic postural control was evaluated during the transition from double-leg to single-leg standing. Each patient stood on a force plate, lifted the less affected limb as fast as possible, and maintained single-leg standing with the more affected limb. The COP movements corresponding to anticipatory postural adjustment (APA) and transitional phases were assessed. The maximum displacement and peak velocity of the COP movements in the medial–lateral direction were calculated. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used for the subjective assessment of ADL and QOL. Pearson’s product correlation analysis was performed to investigate the associations of COP movements in the APA and transitional phases with KOOS-ADL and KOOS-QOL.

Results

In the APA phase, the maximum COP displacement was significantly correlated with KOOS-ADL (r = -0.353, P = 0.035) and KOOS-QOL (r = -0.379, P = 0.023). In the transitional phase, the maximum COP displacement and peak COP velocity were significantly correlated with KOOS-ADL (maximum displacement: r = 0.352, P = 0.035; peak velocity: r = 0.438, P = 0.008) and with KOOS-QOL (maximum displacement: r = 0.357, P = 0.032; peak velocity: r = 0.343, P = 0.040).

Conclusions

The present study showed that smaller COP movements in the APA phase and smaller and slower COP movements in the transitional phase correlated with poorer ADL and QOL conditions in patients with knee OA. These findings suggest that poor dynamic postural control is associated with poor ADL and QOL conditions in patients with moderate-to-severe medial knee OA. Conservative treatment for patients with knee OA may need to focus on dynamic postural control during the transition from double-leg to single-leg standing.

Modifying Stride Length in Isolation and in Combination With Foot Progression Angle and Step Width Can Improve Knee Kinetics Related to Osteoarthritis; A Preliminary Study in Healthy Subjects

The purpose of this study was to determine the effects of modifying stride length (SL) on knee adduction and flexion moments, two markers of knee loading associated with medial-compartment knee osteoarthritis (OA) progression. This study also tested if SL modifications, in addition to foot progression angle (FP) and step width (SW) modifications, provide solutions in more subjects for reducing knee adduction moment (KAM) without increasing knee flexion moment (KFM), potentially protecting the joint. Fourteen healthy subjects (six female) were enrolled in this preliminary study. Walking trials were collected first without instructions, and then following foot placement instructions for 50 combinations of SL, FP, and SW modifications. Repeated measures analysis of variance was used to detect group-average effects of footprint modifications on maximum KAM and KFM and on KAM impulse. Subject-specific dose-responses between footprint modifications and kinetics changes were modeled with linear regressions, and the models were used to identify modification solutions, per subject, for various kinetics change conditions. Shorter SL significantly decreased the three kinetics measures (p < 0.01). Potential solutions for 10% reductions in maximum KAM and KAM impulse without increasing maximum KFM were identified for five subjects with FP and SW modifications. A significantly higher proportion of subjects had solutions when adding SL modifications (11 subjects, p = 0.04). In conclusion, SL is a valuable parameter to modify, especially in combination with FP and SW modifications, to reduce markers of medial knee loading. Future work is needed to extend these findings to osteoarthritic knees.

Correlation between static limb alignment and peak knee adduction angle during gait is affected by subject pain in medial knee osteoarthritis

BACKGROUND

Although increases in knee adduction moment (KAM) and angle (KAA) during gait are considered key pathologies that produce mechanical overload in the medial compartment of knee osteoarthritis (OA), it is unclear how these pathologies are related to subjective pain. The purpose of this study was to examine how subjective pain is related to such pathologies.

METHODS

Gait analysis was performed in 31 participants with medial knee OA. The knees were classified into three groups based on Kellgren-Lawrence (KL) grade: early (0 and 1), moderate (2), and severe (3 and 4). Subjective pain was evaluated by the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index pain score. The knees were classified into low- and high-pain groups based on the pain score.

RESULTS

The WOMAC pain score did not correlate with either peak KAM or peak KAA. Although a positive correlation between static limb alignment and peak KAA was observed in the low-pain group, it was not observed in the high-pain group. Knee flexion angle at heel strike correlated negatively with the gap between static femorotibial angle and peak KAA in the high-pain group.

CONCLUSIONS

Although a direct correlation between subjective pain and peak KAM or KAA was not observed, our results suggest a compensatory movement in the high-pain group of participants to reduce KAA increases in the early stance phase. Such movements would be one of the reasons why it is difficult to obtain a consistent relationship between subjective pain and load-related parameters.

The relationship between urinary C-Telopeptide fragments of type II collagen, knee joint load, pain, and physical function in individuals with medial knee osteoarthritis

OBJECTIVE

Considering the osteoarthritis (OA) model that integrates the biological, mechanical, and structural components of the disease, the present study aimed to investigate the association between urinary C-Telopeptide fragments of type II collagen (uCTX-II), knee joint moments, pain, and physical function in individuals with medial knee OA.

METHODS

Twenty-five subjects radiographically diagnosed with knee OA were recruited. Participants were evaluated through three-dimensional gait analysis, uCTX-II level, the WOMAC pain and physical function scores, and the 40m walk test. The association between these variables was investigated using Pearson's product-moment correlation, followed by a hierarchical linear regression, controlled by OA severity and body mass index (BMI).

RESULTS

No relationship was found between uCTX-II level and knee moments. A significant correlation between uCTX-II level and pain, physical function, and the 40m walk test was found. The hierarchical linear regression controlling for OA severity and BMI showed that uCTX-II level explained 9% of the WOMAC pain score, 27% of the WOMAC physical function score, and 7% of the 40m walk test.

CONCLUSION

Greater uCTX-II level is associated with higher pain and reduced physical function and 40m walk test performance in individuals with medial knee OA.

The Relationship between Knee Adduction Moment and Knee Osteoarthritis Symptoms according to Static Alignment and Pelvic Drop

Objectives

To investigate the relationship between external knee adduction moment (KAM) and knee osteoarthritis (OA) symptoms according to static alignment and pelvic drop.

Methods

Ninety-five participants with symptomatic knee OA were included. Radiographic severity was graded by Kellgren and Lawrence (KL) scale. The hip-knee-ankle (HKA) angle was used to assess limb alignment from a full-length lower-limb radiograph. KAM-related variables (peak KAM and KAM impulse) and pelvic drop angle were determined from 3D gait analysis. Symptoms were assessed via visual analog scale (VAS) for pain and hospital for special surgery (HSS) score for physical function. The relationship between KAM and symptoms was evaluated according to radiographic severity and pelvic drop using linear models.

Results

According to the more affected knee in the varus group, both the two KAM-related measures (peak KAM and KAM impulse) were positively associated with greater VAS pain and were negatively associated with HSS score. Only peak KAM was correlated with VAS and HSS in the valgus group. VAS pain score of the more affected knee was positively correlated with pelvic drop angle. Stratified by pelvic drop angle, KAM-related variables were more positively associated with VAS pain and negatively associated with HSS score for patients with pelvic drop angle ≤3 degrees. The relationships between KAM and symptoms according to radiographic disease severity remained confusing.

Conclusions

Static alignment and pelvic drop angle significantly affected relationships between KAM-related variables and knee OA symptoms, which may explain the confusing results as shown by previous studies.

Accuracy of classifying the movement strategy in the functional reach test using a markerless motion capture system

The purpose of this study was to examine the accuracy of classifying the movement strategy in the functional reach test (FRT) using a markerless motion capture system (MLS) on the basis of values acquired with a marker-based motion capture system (MBS). Sixty young, injury-free individuals participated in this study. The task action involved reaching forward in the standing position. Using the Microsoft Kinect v2 as an MLS and Vicon as a MBS, the coordinates of the hip joints, knee joints and ankle joints were measured. The hip and ankle joint angles during the task were calculated from the coordinate data. These angles between MLS and MBS were compared using a paired t-test. The accuracy of movement strategy defined using MLS was examined based on the MBS. A t-test showed a significant difference in both the hip and ankle joint angles between systems (p < .01). However, in case of using data of left ankle joint, indices of the classification accuracy of MLS were 0.825 for sensitivity, 1.000 for specificity, infinity for positive likelihood ratio and 0.175 for negative likelihood ratio. The results for the right joint angle were similar to those of the left joint angle. Although the absolute measures in the hip and joint angles obtained using MLS differ from MBS, the MLS may be useful for accurately classifying the movement strategy adopted in the FRT.

Patients with early-stage knee osteoarthritis and knee pain have decreased hip abductor muscle strength while descending stairs

INTRODUCTION/OBJECTIVES

This study aimed to investigate the association between hip abductor muscle strength and knee pain in patients with early-stage knee osteoarthritis (OA) while ascending and descending stairs.

METHOD

This cross-sectional study included individuals with early-stage knee OA (Kellgren/Lawrence grades 1 or 2). Knee pain while ascending and descending stairs was evaluated using a knee OA-related health domain measure (Japanese Knee Osteoarthritis Measure). Knee extension and hip abductor muscle strength were also evaluated. The association between hip abductor muscle strength and knee pain while ascending and descending stairs was evaluated using multiple regression analysis.

RESULTS

A total of 157 participants were included in the final analysis. After the adjustment for age, sex, and knee extension strength, those with knee pain while descending stairs showed significantly decreased hip abductor muscle strength (β, - 0.09; 95% confidence interval [CI], - 0.19 to - 0.003). In contrast, after the adjustment for age, sex, and knee extension muscle strength, those with knee pain while ascending stairs did not have significantly decreased hip abductor muscle strength (β, - 0.06; 95% CI, - 0.15 to 0.02).

CONCLUSIONS

Patients with early-stage knee OA and knee pain while descending stairs had significantly reduced hip abductor muscle strength.

Mechanical energy efficiency for stepping up and down in persons with medial knee osteoarthritis

BACKGROUND

Energetic cost contributes to movement impairments observed during stair negotiation in persons with knee osteoarthritis. Specifically, the intersegmental mechanical energy exchange may be diminished in the presence of pathologies.

RESEARCH QUESTION

The purpose of this study was to evaluate mechanical energy efficiency in persons with knee osteoarthritis during stepping up and down based on mechanical energy analysis.

METHODS

Sixteen patients with medial knee osteoarthritis and 16 age-matched controls participated. A three-dimensional motion analysis system and force platforms were used to acquire biomechanical data. The participants were instructed to ascend/descend a 2-step staircase. The mechanical power exhibited during the stance phase at the lower step of the staircase were computed. Mechanical Energy Expenditure (MEE) was calculated as the integral of net joint power at each joint. Mechanical Energy Compensation (MEC) was defined as the proportion of muscle energy compensated by inter-segmental energy transfer. According to energy transfer modes, MEE and MEC were determined separately as three phases: concentric and eccentric transfer phases and no-transfer phase.

RESULTS

While stepping up, the patient group performed the task with less MEC at the ankle joint, which was observed prior to push-off. The patient group displayed less mechanical energy transfer from the shank to the foot segment. The concentric MEC at the hip joint in the late-stance phase of stepping down was lower in the patient group, which meant patients demonstrated less mechanical energy transfer from the pelvis to the thigh segment.

SIGNIFICANCE

It was disclosed that persons with knee osteoarthritis demonstrated less mechanical energy transfer while stepping up and down.

Measurement of the total body center of gravity during sit-to-stand motion using a markerless motion capture system

PURPOSE

In order to evaluate the movement strategy in sit-to-stand (STS) motion, it is necessary to measure the center of gravity (COG). However, there is no established method for enabling this using convenience device in the clinical setting. The purpose of this study was to validate the measurement of the COG during the STS motion using an inexpensive, portable and markerless motion capture system (MLS).

METHOD

Eighteen healthy adults participated in our study. The coordinates of the joint centers during the STS motion were collected using the Microsoft Kinect system (as a MLS) and the Vicon system (as a marker-based motion capture system [MBS]). The center of mass of each segment-which was calculated based on the segmental mass and length-were synthesized to calculate the COG. The displacement, velocity, acceleration of the COG during the STS motion were calculated from the data obtained using each system and compared between systems.

RESULTS

The two systems showed significant difference in their measurements of displacement in both the vertical and anteroposterior directions. However, in the anteroposterior direction, there was no significant difference in the measurements of either velocity or acceleration.

CONCLUSION

Our results suggested the validity of the COG in the anteroposterior direction during the STS motion measured using the MLS. The method developed in the present study enables the evaluation of a patient's movement strategy.

Is the Wedged Insole an Effective Treatment Option When Compared with a Flat (Placebo) Insole: A Systematic Review and Meta-Analysis

BACKGROUND

Using the lateral wedge insole is a conservative management strategy for knee osteoarthritis. The theoretical basis for this intervention is to correct femorotibial angle, thereby reducing pain and optimising function.

OBJECTIVE

This systematic review evaluates the evidence on the effectiveness of wedge insole compared with flat insole for the treatment of knee osteoarthritis.

METHODS

A systematic review was performed, searching published (MEDLINE, EMBASE, CNKI, Cochrane Library, and Web of Science) and unpublished literature from their inception to April 2018. Randomized controlled trials (RCTs) that compared the use of wedge insole with a flat insole were included. Risk of bias and clinical relevance were assessed, and outcomes were analysed through meta-analysis.

RESULT

From a total of 413 citations, 8 studies adhered to the a priori eligibility criteria. The WOMAC pain was shown to be statistically nonsignificant change with the use of wedge insole (SMD=0.07), and low heterogeneity (I2=22%) and a 95% CI that crossed zero (95% CI: -0.09 to 0.24). The 5 independent trials were not significant in improving pain score (SMD = -0.02, 95% CI: -0.19 to 0.16). This review also revealed no significance in improving Lequesne index (SMD = -0.27, 95% CI: -0.72 to 0.19). The meta-analysis from the 2 independent trials was significant in improving femorotibial angle (SMD = -0.41, 95% CI: -0.73 to -0.09). In conclusion, this meta-analysis suggested that lateral wedge insoles can improve femorotibial angle but are of no benefit with pain and functions in knee osteoarthritis.

Acute effects of different orthotic interventions on knee loading parameters in knee osteoarthritis patients with varus malalignment

BACKGROUND

Knee osteoarthritis (KOA) is the most common form of arthritis with an estimated lifetime prevalence of 45%. The use of orthotic devices is a generally accepted conservative therapy in KOA. A new conservative treatment is an ankle-foot orthosis (AFO); however, studies on the biomechanical effects are limited. The aim of this study was to examine the acute effects of different orthotic devices (AFO, knee brace and wedged shoes) on (un)loading parameters in subjects with KOA.

METHODS

Fifty-two medial KOA patients (mean age 59 (standard deviation (SD) 10) years and mean body mass index 27.5 (SD 4.9) kg/m²) were recruited. Three-dimensional gait analysis was undertaken with different interventions in a randomized order: control (own shoes), new AFO, conventional unloader brace and laterally wedged shoes (six degrees).

RESULTS

Significant decreases of 27% and nine percent in first peak knee adduction moment (KAM) were observed for the AFO and wedged shoes, respectively, in comparison with the control. Significant decreases of 21%, seven percent and 18% in the KAM impulse were observed for the AFO, brace and wedged shoes, respectively, compared to the control. The knee flexion moment (KFM) increased compared to the control for all conditions, but only significantly while using the AFO, showing an increase of 26% as compared to the control.

CONCLUSIONS

The AFO and wedged shoes were more effective in unloading the medial compartment of the knee compared to the unloader brace. However, the effect of an increased KFM on KOA remains unclear and requires further investigation.

Development of a questionnaire survey to evaluate lower limb function of patients with knee osteoarthritis

This study aimed to develop a self-questionnaire index relevant to lower limb functional assessment reflecting clinical symptoms and activity restrictions associated with activities of daily living (ADL) for patients with knee osteoarthritis. This cross-sectional study enrolled patients with knee osteoarthritis (Kellgren/Lawrence grade ≥ 1). Participants evaluated clinical symptoms and activity restrictions using self-reported questionnaires. Radiographic evaluation, knee joint range of motion (ROM), and lower limb muscle strength were assessed. Associations between clinical symptoms, activity restrictions, and knee and hip joint function were evaluated using multiple and logistic regression analysis. Overall, 142 participants were included in the final analysis. Patients with knee pain while rising from a chair had lower knee and hip extension strength (knee extension β = - 0.28; 95% confidence interval (CI), - 0.41 to - 0.14; P < 0.0001; hip extension β = - 0.26; 95% CI, - 0.42 to - 0.08; P = 0.0034), and restricted knee extension ROM (odds ratio [OR] = 2.17; 95% CI, 1.02-4.63; P = 0.041). Patients with knee pain during stair climbing, turning or who were unable to stand on one leg without external support had reduced hip abduction muscle strength (β = - 0.17; 95% CI, - 0.27 to - 0.07; P = 0.0008). Patients with knee pain while rising from a chair or stepping showed more severe knee joint degeneration on radiographic evaluation (OR = 3.26; 95% CI, 1.11-10.91; P = 0.03). The self-questionnaire index reflected clinical symptoms and activity restrictions associated with ADL and was significantly associated with lower limb function in individuals with knee osteoarthritis.

Effect of knee unloading shoes on regional plantar forces in people with symptomatic knee osteoarthritis - an exploratory study

Background

Knee 'unloading' footwear can reduce the external knee adduction moment in people with knee osteoarthritis, yet effects of these shoes on regional plantar forces are unknown. We evaluated the effects of unloading shoes on in-shoe regional plantar forces, and whether measures of foot posture and/or mobility moderate these effects in people with symptomatic knee osteoarthritis.

Methods

In this exploratory study 21 participants underwent testing while wearing knee unloading shoes (ASICS GEL-Melbourne OA) and conventional shoes in random order. Peak total forces were compared across conditions for: lateral heel, medial heel, lateral forefoot, and medial forefoot. Arch index, centre of pressure position and medial-lateral heel peak force ratio were also evaluated. Foot posture, foot mobility magnitude and navicular drop were separately added to the mixed linear model to investigate if these modified the effect of footwear on outcomes.

Results

Unloading shoes significantly increased lateral heel and lateral forefoot force (12.9 and 20.2% respectively, all P < 0.001), with concurrent decreases in the medial heel (8.9%, P = 0.001) and medial forefoot (9.9%, P = 0.005). Unloading shoes significantly shifted the centre of pressure anteriorly (4.7%, P < 0.001) and laterally (5.6%, P = 0.034), but did not affect the arch index (8.7%, P = 0.093). Foot posture, foot mobility magnitude and navicular drop did not moderate the effect of footwear on outcomes.

Conclusion

Compared to conventional shoes, unloading shoes caused a lateral shift in foot pressure and force patterns. Although these effects were not moderated by foot posture, FMM or navicular drop, variability in the individual increases in lateral heel force suggests participant characteristics other than foot posture may play a role.

Trial registration

ACTRN12613000851763. Registered 02 August 2013.

Validity of the total body centre of gravity during gait using a markerless motion capture system

PURPOSE

The purpose of this study was to examine the validity of total body centre of gravity (COG) measurement during gait with markerless motion capture system (MLS) on the basis of values acquired with a marker-based motion capture system (MBS).

MATERIALS AND METHODS

Thirty young healthy subjects walked on a flat surface as coordinate data from their bodies were acquired using the Kinect v2 (as a MLS) and Vicon systems (as a MBS). COG was calculated using coordinate data of the total body. Comparisons of COG ensemble curves in the mediolateral and vertical directions were performed between MLS and MBS throughout the gait cycle. The relative consistency between these systems was assessed using Pearson correlation coefficients.

RESULTS

The COG trajectory made by using MLS data followed the trend of the COG trajectory with MBS in the mediolateral direction. In the vertical direction, however, the COG trajectories did not match between two systems. High correlation coefficients (r  > 0.79) were observed from 30% to 80% of the gait cycle. The greatest difference of COG between MLS and MBS in the mediolateral direction was 1.1 mm. Differences in the vertical direction appeared to be proportional to the distance between the participant and the Kinect v2 sensor.

CONCLUSION

In the mediolateral direction, COG calculated with MLS data during gait was validated with COG calculated on the basis of a MBS. Further correction of systematic error is necessary to improve the validity of COG calculations in the vertical direction.

Immediate synergistic effect of a trunk orthosis with joints providing resistive force and an ankle-foot orthosis on hemiplegic gait

Purpose

The synergistic effects of a trunk orthosis and an ankle-foot orthosis (AFO) in stroke patients with a hemiplegic gait are unclear. We previously developed a trunk orthosis with joints providing resistive force (TORF) to modify malalignment of the trunk and pelvis and confirmed its positive effects in stroke patients during level walking without an AFO. The aim of the present study was to determine if this trunk orthosis and an AFO have synergistic effects during level walking in community-dwelling patients with chronic stroke.

Methods

Twenty-eight community-dwelling stroke patients performed level walking at a self-selected speed with an AFO and again while wearing a TORF (TORF group) or a corset (control group). Spatiotemporal, kinematic, and kinetic data were recorded using a three-dimensional motion analysis system.

Results

When compared with the control group, the TORF group showed significant increases in walking speed, number of steps on the paretic leg per minute, and peak ankle plantar flexion moment during the single stance phase.

Conclusion

The TORF increased the ankle joint plantar flexion moment at the end of the single stance phase during level walking in stroke patients, leading to an increase in their gait speed because of the modified trunk and pelvis alignment.

Moderators and mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis: an exploratory analysis of the SHARK randomised controlled trial

OBJECTIVE

To investigate moderators and biomechanical mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis (OA).

METHODS

Exploratory analysis from 164 participants in a clinical trial comparing unloading (ASICS GEL-Melbourne OA) to conventional walking shoes. The primary outcome was 6-month change in knee pain (11-point numerical rating scale (NRS)). Moderators included baseline peak knee adduction moment (KAM), radiographic severity (Kellgren & Lawrence (KL) scale), body mass, foot posture, neuropathic pain and diffuse knee pain. Mediators included change in peak KAM and KAM impulse.

RESULTS

Radiographic severity was the only moderator to interact with footwear group (P = 0.02). Participants with KL = 2 experienced greater pain reductions with conventional compared to unloading shoes (mean difference in change in pain -1.64 units, 95% CI -3.07, -0.21), while unloading shoes tended to result in greater pain reductions than conventional shoes in KL = 3 (0.98, 95% CI -0.44, 2.39) and KL = 4 (0.64, 95% CI -0.64, 1.93). No variable showed any significant mediating effect in the entire cohort. However, there was some evidence that unloading shoes may reduce pain through reductions in peak KAM (indirect effect -0.31, 95% CIs -0.65, 0.03; P = 0.07) in people with KL ≥ 3, compared to conventional shoes.

CONCLUSION

Unloading shoes conferred additional symptomatic benefits over conventional shoes in people with moderate to severe knee OA. There was some evidence effects may be mediated by a reduction in peak KAM. However, we were underpowered for subgroup analyses. These patients may represent a subgroup to which biomechanical interventions designed to reduce the KAM may be more effectively targeted.

Trunk lean gait decreases multi-segmental coordination in the vertical direction

[Purpose] The strategy of trunk lean gait to reduce external knee adduction moment (KAM) may affect multi-segmental synergy control of center of mass (COM) displacement. Uncontrolled manifold (UCM) analysis is an evaluation index to understand motor variability. The purpose of this study was to investigate how motor variability is affected by using UCM analysis on adjustment of the trunk lean angle. [Subjects and Methods] Fifteen healthy young adults walked at their preferred speed under two conditions: normal and trunk lean gait. UCM analysis was performed with respect to the COM displacement during the stance phase. The KAM data were analyzed at the points of the first KAM peak during the stance phase. [Results] The KAM during trunk lean gait was smaller than during normal gait. Despite a greater segmental configuration variance with respect to mediolateral COM displacement during trunk lean gait, the synergy index was not significantly different between the two conditions. The synergy index with respect to vertical COM displacement during trunk lean gait was smaller than that during normal gait. [Conclusion] These results suggest that trunk lean gait is effective in reducing KAM; however, it may decrease multi-segmental movement coordination of COM control in the vertical direction.

Medial knee loading is altered in subjects with early osteoarthritis during gait but not during step-up-and-over task

This study evaluates knee joint loading during gait and step-up-and-over tasks in control subjects, subjects with early knee OA and those with established knee OA. Thirty-seven subjects with varying degrees of medial compartment knee OA severity (eighteen with early OA and sixteen with established OA), and nineteen healthy controls performed gait and step-up-and-over tasks. Knee joint moments, contact forces (KCF), the magnitude of contact pressures and center of pressure (CoP) location were analyzed for the three groups for both activities using a multi-body knee model with articular cartilage contact, 14 ligaments, and six degrees of freedom tibiofemoral and patellofemoral joints. During gait, the first peak of the medial KCF was significantly higher for patients with early knee OA (p = 0.048) and established knee OA (p = 0.001) compared to control subjects. Furthermore, the medial contact pressure magnitudes and CoP location were significantly different in both groups of patients compared to controls. Knee rotation moments (KRMs) and external rotation angles were significantly higher during early stance in both patient groups (p < 0.0001) compared to controls. During step-up-and-over, there was a high variability between the participants and no significant differences in KCF were observed between the groups. Knee joint loading and kinematics were found to be altered in patients with early knee OA only during gait. This is an indication that an excessive medial KCF and altered loading location, observed in these patients, is a contributor to early progression of knee OA.

Rear foot kinematics when wearing lateral wedge insoles and foot alignment influence the effect of knee adduction moment for medial knee osteoarthritis

Lateral wedge insoles (LWIs) are prescribed for patients with medial knee osteoarthritis to reduce the external knee adduction moment (KAM). However, the biomechanical effects of LWIs are limited in some patients. The purpose of this study was to investigate whether the biomechanical effects of LWIs depend on individual foot alignment and to examine the relationship between change in KAM and changes in foot and ankle biomechanics when wearing LWIs. Twenty-one patients participated in this study. They were categorized into normal or abnormal foot groups based on the foot posture index (FPI). All patients were requested to perform a normal gait under barefoot and LWI conditions. A three-dimensional motion analysis system was used to record 1st and 2nd KAM, knee adduction angular impulse (KAAI), center of pressure displacement, and knee-ground reaction force lever arm. Furthermore, the foot and ankle frontal plane kinematic parameters were evaluated. The 1st KAM was significantly reduced under the LWI condition compared to that under the barefoot condition in the normal foot group. In contrast, there was no significant difference in 1st KAM between both conditions in the abnormal foot group. Decreased rear foot eversion strongly correlated with reduction in the 1st KAM in the normal foot group. These findings suggested that it is helpful to assess individual foot alignment to ensure adequate insole treatment for patients with medial knee osteoarthritis and that decreased rear foot eversion during the early stance phase is significantly involved in the reduction of 1st KAM when wearing LWIs with normal feet.

Daily cumulative hip moment is associated with radiographic progression of secondary hip osteoarthritis

OBJECTIVE

To investigate whether higher daily cumulative hip moment at baseline is associated with subsequent radiographic progression of hip osteoarthritis (OA) over 12 months.

DESIGN

Fifty patients with secondary hip OA, excluding patients with end-stage hip OA, participated in this prospective cohort study. Joint space width (JSW) of the hip was measured at baseline and 12 months later. With radiographic progression of hip OA (>0.5 mm/year in JSW) as dependent variable (yes/no), univariable and multivariable logistic regression analyses were performed to assess the association between load-related parameters during gait (i.e., peak hip moment, hip moment impulse, and daily cumulative hip moment [product of hip moment impulse and mean steps/day]) and hip OA progression with and without adjustment for age, body weight, and minimum JSW.

RESULTS

Of the 50 patients (47.4 ± 10.7 years old), 21 (42.0%) were classified into the progression group. The higher daily cumulative hip moment in the frontal plane at baseline was statistically significantly associated with radiographic progression of hip OA (adjusted odds ratio (OR) [95% confidence interval (CI)], 1.34 [1.06-1.70]; P = 0.013). The higher daily cumulative hip moment in the sagittal plane was also approaching significance in its association with hip OA progression (adjusted OR, 1.80 [0.99-3.26]; P = 0.052).

CONCLUSIONS

In the female patients with secondary hip OA, higher daily cumulative hip moment, particularly in the frontal plane, was a predictor of radiographic progression of hip OA over 12 months. Reduction in daily cumulative hip moment by modification in gait and physical activity may potentially slow hip OA progression.

Effects of footwear on the knee adduction moment in medial knee osteoarthritis: classification criteria for flat flexible vs stable supportive shoes

OBJECTIVE

To validate simple criteria that distinguish flat flexible from stable supportive walking shoes by comparing their effects on the knee adduction moment (KAM) in people with medial knee osteoarthritis (OA).

DESIGN

This was a cross-sectional biomechanical study. We proposed five criteria to differentiate flat flexible from stable supportive shoes, and selected three pairs of shoes representing each class for biomechanical testing. 28 participants aged ≥50 years with symptomatic medial knee OA underwent gait analysis barefoot and wearing each of the six selected shoes, in random order. Differences in the peak KAM, KAM impulse and peak knee flexion moment (KFM) across test conditions were evaluated with a two-way repeated measures analysis of variance (ANOVA). Immediate changes in walking pain between conditions were also compared.

RESULTS

Increases in KAM from barefoot were lower with each of the three flat flexible shoe styles (peak KAM: 6.1-8.9%; KAM impulse: 2.4-5.1%) compared to their stable supportive counterparts (peak KAM: 11.6-15.1%; KAM impulse 10.5-13.2%). There was a significant main effect for footwear class on peak KAM and KAM impulse, whereby stable supportive shoes increased the KAM significantly more than flat flexible shoes (P < 0.001). There were no differences in the KFM or immediate walking pain between footwear classes.

CONCLUSIONS

Our proposed criteria can be used by researchers and clinicians to select flat flexible shoes for people with medial knee OA to minimise knee loading. Future research should evaluate whether wearing shoes based on these criteria translates to improvements in knee OA symptoms and/or slows structural disease progression.

The knee adduction moment and knee osteoarthritis symptoms: relationships according to radiographic disease severity

OBJECTIVE

To investigate relationships between external knee adduction moment parameters (KAM) and osteoarthritis (OA) symptoms according to disease severity.

DESIGN

164 participants with symptomatic medial knee OA were included. Radiographic severity was graded by (1) Kellgren & Lawrence (KL) scale (Grade 2, n = 49; Grade, n = 52; Grade 4, n = 63) and; (2) medial tibiofemoral joint space narrowing (JSN) (Grade 1, n = 47; Grade 2, n = 50; Grade 3, n = 67). KAM-related parameters (peak KAM, KAM impulse and cumulative load) were determined from three-dimensional gait analysis and pedometry. Cumulative load was determined by multiplying KAM impulse by the average number of steps/day recorded over at least 5 days. Symptoms were assessed via numeric rating scale ((NRS), pain) and Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index (pain and physical function). Relationships between KAM parameters (independent variables) and symptoms (dependent variables) were evaluated by radiographic severity using linear models, adjusting for covariates.

RESULTS

In mild disease (either KL Grade 2 or JSN Grade 1), there were no associations between KAM and symptoms. In moderate disease of KL Grade 3, higher KAM impulse was associated with greater WOMAC pain. In severe disease (KL Grade 4), higher KAM impulse was associated with less WOMAC pain (KL Grade 4), while higher peak KAM was associated with better function (KL Grade 4). Higher cumulative knee adduction load was associated with less pain on both NRS and WOMAC (JSN Grade 3) as well as better function (both JSN Grade 3 and KL Grade 4).

CONCLUSIONS

Relationships between KAM-related parameters and symptoms differ according to underlying radiographic OA severity.

A three dimensional approach for quantifying resultant loading at the knee

BACKGROUND

Clinical effectiveness of lateral wedges for knee osteoarthritis is inconsistent across studies. One explanation is that knee loading is not fully described by the peak frontal-plane knee moment. The purpose of this study was to propose a 3D resultant approach to describing moments at the knee and evaluate how this moment changes in response to lateral wedges.

METHODS

Walking gait analysis was performed on 20 individuals with knee osteoarthritis, in their own shoes, with and without a six millimeter lateral wedge insole. Frontal-plane and 3D resultant moments were calculated for each participant and footwear condition. Paired t-tests identified differences between footwear conditions, correlations identified relationships between frontal-plane and 3D resultant moments, and regressions assessed relationships between moments and pain.

RESULTS

Significant reductions to peak frontal-plane moments (p=0.001) and 3D resultant moments at the same time point (p=0.042) were observed with lateral wedges. While an overall significant correlation was observed between change in frontal-plane moments and change in 3D resultant moments with a lateral wedge (r=0.68, p=0.001), 5/20 participants experienced disparate results where the frontal-plane moment was reduced yet the 3D moment increased.

CONCLUSIONS

While lateral wedges alter frontal-plane moment magnitude, the direction of change does not always correspond to the direction of change observed in the 3D resultant moment. Thus resultant knee load may sometimes increase with lateral wedges.

CLINICAL RELEVANCE

Future prospective studies should evaluate if changes in 3D resultant moments, and thus total knee load, offer an explanation as to why some participants do not experience clinical benefit from lateral wedges.

Associations of radiographic degeneration and pain with daily cumulative hip loading in patients with secondary hip osteoarthritis

The purpose of this study was to investigate the associations of radiographic and clinical variables of hip osteoarthritis (OA) with alterations in gait and joint loading in patients with secondary hip OA. Fifty females with secondary hip OA were participated. The minimum joint space width (mJSW) of the hip as a degenerative sign and Sharp and center edge (CE) angles as morphological variables were measured radiographically. Hip joint pain was assessed using a visual analog scale. As gait variables, walking speed, range of hip motion, hip moment peak, and hip moment impulse were calculated. Daily cumulative hip loading was calculated as the hip moment impulse multiplied by the mean number of steps per day. After bivariate correlation analyses between dependent (mJSW and pain) and independent variables (age, body mass index, sharp/CE angles, steps per day, and gait variables), separate forward-backward stepwise multiple regression analyses were performed for each dependent variable. Daily cumulative hip loading in the sagittal plane (β = 0.30, p = 0.021) and age (β = -0.36, p = 0.007) were significantly associated with the mJSW. Walking speed (β = -0.36, p = 0.008) and age (β = 0.29, p = 0.031) were significantly associated with hip joint pain. Decrease in daily cumulative hip loading in the sagittal plane was associated with mJSW independently of age. Although the causal relationship was not clear, patients with hip OA reduced total exposure to hip joint loading adaptively rather than lowering the hip moment peak concerning worsening of hip degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1977-1983, 2016.

Foot alignments influence the effect of knee adduction moment with lateral wedge insoles during gait

Lateral wedge insoles (LWIs) reduce the peak external knee adduction moment (KAM). However, the efficacy of LWIs is limited in certain individuals for whom they fail to decrease KAM. Possible explanations for a lack of desired LWI response are variations in foot alignments. The purpose of this study was to evaluate whether the immediate biomechanical effects of LWIs depend on individual foot alignments during gait. Fifteen healthy adults participated in this study. Their feet were categorized as normal, pronated, and supinated using the foot posture index. All subjects were subsequently requested to perform a normal gait under barefoot and LWI conditions. A three-dimensional motion analysis system was used to record the kinematic and kinetic data, included peak KAM, KAM impulse (KAAI), center of pressure displacement, and knee-ground reaction force lever arm (KLA). Furthermore, lower limb frontal plane kinematic parameters at the rear foot, ankle, knee, and hip were evaluated. Among all feet, there was no significant difference in the peak KAM and KAAI between the conditions. In contrast, the peak KAM was significantly reduced under the LWI condition relative to the barefoot condition in the normal foot group. Reductions in the peak KAM were correlated with a more lateral center of pressure and reduced KLA. In addition, a reduced KLA was correlated with decreased hip adduction. LWIs significantly reduced the peak KAM in normal feet, indicating that biomechanical effects of LWIs vary between individual foot alignments. Our findings suggest that it is helpful to assess individual foot alignment to ensure adequate insole treatment for patients with knee osteoarthritis.

General scheme to reduce the knee adduction moment by modifying a combination of gait variables

Reducing the knee adduction moment (KAM) is a promising treatment for medial compartment knee osteoarthritis (OA). Although several gait modifications to lower the KAM have been identified, the potential to combine modifications and individual dose-responses remain unknown. This study hypothesized that: (i) there is a general scheme consisting of modifications in trunk sway, step width, walking speed, and foot progression angle that reduces the KAM; (ii) gait modifications can be combined; and (iii) dose-responses differ among individuals. Walking trials with simultaneous modifications in step width, walking speed, progression angle, and trunk sway were analyzed for 10 healthy subjects. Wider step width, slower speed, toeing-in, and increased trunk sway resulted in reduced first KAM peak, whereas wider step width, faster speed, and increased trunk sway reduced the KAM angular impulse. Individual regressions accurately modeled the amplitude of the KAM variables relative to the amplitude of the gait modification variables, while the dose-responses varied strongly among participants. In conclusion, increasing trunk sway, increasing step width, and toeing-in are three gait modifications that could be combined to reduce KAM variables related to knee OA. Results also indicated that some gait modifications reducing the KAM induced changes in the knee flexion moment possibly indicative of an increase in knee loading. Taken together with the different dose-responses among subjects, this study suggested that gait retraining programs should consider this general scheme of modifications with individualization of the modification amplitudes. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1547-1556, 2016.