Assessment of fore-, mid-, and rear-foot alignment and their association with knee symptoms and function in patients with knee osteoarthritis

The causal relationship between hallux valgus and endogenous pathogenic factors: A 2-sample Mendelian randomization

Notably, several factors are associated with hallux valgus (HV); however, their causal relationship remains unclear. In this study, a 2-sample Mendelian randomization (MR) analysis was performed to investigate the casual relationship between 9 endogenous risk factors and HV, aiming to provide a foundation for the clinical management of HV. Exposure factors such as body mass index (BMI), BMI (male), BMI (female), acquired flatfoot, rheumatoid arthritis, gout, knee osteoarthritis, hip osteoarthritis, and Ehlers-Danlos syndrome were considered, with HV as the outcome. Exposure and outcome data were obtained from the IEU Open Genome-wide association study project, UK Biobank, and FinnGen project. Strongly correlated (P < 5×10-08/5×10-06) single nucleotide polymorphisms (SNPs) were selected from the exposure dataset, and those associated with exposure were selected from the HV dataset. The intersection of these SNPs was used as instrumental variables. Five modes were used for the analysis: inverse variance-weighted (IVW), MR-Egger regression, weighted median (WME), simple mode, and weighted mode. MR analysis results of BMI show that except for MR-Egger, the other 4 modes are significant (P < .05), and the β directions are consistent among the 5 methods. For the 4 BMI (male) methods, except for the simple mode, the P- and β-values of the other results all suggest a positive causal relationship between BMI (male) and HV. Flatfoot-IVW and WME results were <.05, indicating statistical significance, whereas MR-Egger, simple mode, and median mode had no statistical significance. However, their β-values were consistent with those of IVW and WME. Further mediation MR analysis suggested that the effect mediated by HV accounts for 13.33% [95% CI (0.03-0.24)] of the total causal effect between the BMI and flatfoot, indicating HV as a mediator of the causal relationship between the BMI and flatfoot. However, the remaining 6 factors had no direct causal association with HV (P < .05). Flatfoot in all patients and elevated BMI in males are directly associated with HV. Therefore, treating acquired flatfoot and controlling the BMI to prevent HV are recommended.

The association between varus knee deformity and morphological changes in the foot and ankle in patients with end-stage varus knee osteoarthritis

BACKGROUND

This study aimed to (1) determine the association between varus knee deformity and ipsilateral foot and ankle morphology, and (2) evaluate the relationship between varus knee deformity and foot and ankle pain in patients with end-stage varus knee osteoarthritis (KOA).

METHODS

A total of 213 patients who underwent primary total knee arthroplasty for end-stage varus KOA were enrolled in this study and divided into a 'severe varus group' (n = 119) and a 'mild varus group' (n = 94) based on preoperative knee varus degree. Morphological parameters and pain incidence in the foot and ankle were compared between the two groups. The correlation between knee varus and foot and ankle morphology was analyzed.

RESULTS

Significant differences in ankle morphology were observed between the two groups. The deformity magnitudes of the hindfoot valgus (P < 0.001) and hallux valgus (HVA, P = 0.028; IMA, P = 0.046) were significantly higher in the severe varus group. Additionally, the incidences of ankle osteoarthritis (OA) (P = 0.005) and hallux valgus (P = 0.028) were higher in the severe varus group. Patients with severe KOA were more likely to experience medial ankle pain (P = 0.023), hindfoot pain (P = 0.034), and multiple pain locations (P = 0.015).

CONCLUSION

Varus knee deformity was associated with morphological changes in the foot and ankle, and the incidence of ankle OA and hallux valgus deformity was significantly higher in patients with severe varus KOA. Patients with severe varus KOA were more prone to medial ankle pain, hindfoot pain, and multiple pain locations, which were associated with corresponding morphological changes.

Center of Pressure in Relation to Foot Morphology and Knee Symptoms in Older Women With Medial Knee Joint Deformity: A Cross-sectional Study

OBJECTIVE

To examine the correlations amongst center of pressure (COP) trajectories, foot morphology, and knee symptoms in older women with medial knee deformity.

DESIGN

This was a cross-sectional study.

SETTING

Participants were recruited from 2 local orthopedic clinics.

PARTICIPANTS

Female patients with medial knee deformity (Kellgren-Lawrence grade ≥1) aged 60 years or older (N=84).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

COP trajectories during comfortable gait were obtained using a plantar pressure distribution platform. As foot morphology metrics, hallux valgus angle, navicular/foot ratio, and leg-heel alignment were measured. The knee society scoring system was used to evaluate knee symptom severity. We used statistical parametric mapping for COP trajectory analysis to reduce the bias caused by data extraction. Multiple linear regression in statistical parametric mapping was used to determine the correlations amongst foot morphology, knee symptom severity, and COP trajectories.

RESULTS

There was a correlation between higher navicular/foot ratio and medial shift on COP at initial contact (0%∼3.0% stance phase, P<.05) and at toe-off (95.3%∼100% stance phase, P=.04). Also, higher navicular/foot ratio was associated with lateral shift of COP during single leg stance phase (8.3%∼80.1% stance phase, P<.01). We also found a significant correlation between lateral shift of COP during loading response phase (6.8%∼19.0% stance phase) and knee symptom severity (P=.03).

CONCLUSIONS

Our results indicated that patients with severe knee symptoms may benefit from intervention to modify the foot arch and to medially shift the COP, which may be capable of relieving knee symptoms. Although our results do not directly show pain reduction, a medial COP shift could indeed reduce pain in cases where knee adduction moment is responsible for pain. These findings may contribute to the further development of conservative intervention, which focus on foot morphology of patients with knee osteoarthritis.

Prevalence and risk factors of knee osteoarthritis: a cross-sectional survey in Nanjing, China

Background

Knee osteoarthritis (KOA) presents a significant public health challenge due to its hazards and increasingly severe trends. Addressing this challenge requires targeted investigation into the prevalence and identification of risk factors for KOA across different regions, especially in populous and vast China. Therefore, a cross-sectional survey was conducted in Nanjing, China, with the aim of investigating the prevalence and risk factors of KOA among individuals aged 50 and above.

Method

A total of 1,045 subjects were selected using the stratified random sampling method and diagnosed with KOA based on the diagnostic criteria established by the Chinese Medical Association. Data on 14 potential risk factors were collected through a self-designed questionnaire and standardized on-site tests. The association between KOA and these risk factors was explored using t-tests, Chi-square tests, and logistic regression analysis.

Results

The prevalence of KOA among the subjects was 23.64%. Multiple logistic regression models indicated that the risk of KOA was significantly higher among women (OR: 5.34, 95% CI: 3.13-9.11), subjects aged 60-69 (OR: 1.83, 95% CI: 1.25-2.69) and over 70 (OR: 2.87, 95% CI: 1.80-4.59), individuals with high school education and above (OR:2.22, 95% CI: 1.37-3.60), those with flatfoot (OR: 1.74, 95% CI: 1.10-2.74), and subjects classified as overweight (OR: 1.91, 95% CI: 1.21-3.04) and obese (OR: 4.63, 95% CI: 2.18-9.85) based on their BMI status. Additionally, the models identified weight (OR: 1.04, 95% CI: 1.01-1.08), 30-s chair stand performance (OR: 0.94, 95% CI: 0.91-0.97), and single-leg stand performance (OR: 0.96, 95% CI: 0.93-0.99) as independent risk factors for KOA.

Conclusion

The prevalence of KOA is remarkable in Nanjing city. The risk factors for KOA include women, older age, higher education, flatfoot, increased weight and BMI, as well as poor performance in 30-s chair stand and single-leg stand tests.

Determinants of Achilles tendon thickness and their influence on knee function and foot alignment in knee osteoarthritis

Knee osteoarthritis (OA) significantly impacts the quality of life of individuals globally. However, the interconnections between Achilles tendon thickness, knee symptoms/functions, and foot alignment remain understudied in knee OA patients. This study determines the relationships between Achilles tendon thickness (ATT), knee symptoms/functions, and foot alignment in knee OA patients, considering their interconnected biomechanical nature. In a cross-sectional analysis involving 122 knee OA patients, Knee injury and Osteoarthritis Outcome Score (KOOS) assessed knee function and symptoms. Forefoot, midfoot, and rearfoot alignment were measured using hallux valgus angle, navicular/foot ratio, and rearfoot angle. The navicular/foot ratio represented the ratio of navicular height to total foot length. ATT was measured using a digital calliper. Pearson correlations and stepwise multiple linear regression models were employed to explore relationships and determinants. Out of 122 participants, 88 (72.1%) were females. ATT correlated significantly with ankle range of motion, forefoot alignment, and midfoot alignment. In stepwise multivariable regression, ankle range of motion, navicular/foot ratio, and age were significantly associated with ATT (adjusted R2 = 0.44). Similarly, KOOS-Symptoms scores were linked to the OA severity, navicular/foot ratio, ankle range of motion, gastrocnemius strength, and age (adjusted R2 = 0.22). KOOS-Function scores were significantly associated with knee OA severity, gastrocnemius strength, ankle range of motion, and age (adjusted R2 = 0.19). Midfoot alignment was significantly associated with ATT and knee symptoms in patients with Knee OA. This suggests potential benefits of interventions targeting both Achilles tendon properties and foot alignment for improved knee OA outcomes.

Modifying loading during gait leads to biochemical changes in serum cartilage oligomeric matrix protein concentrations in a subgroup of individuals with anterior cruciate ligament reconstruction

PURPOSE

Strong observational evidence has linked changes in limb loading during walking following anterior cruciate ligament reconstruction (ACLR) to posttraumatic osteoarthritis (PTOA). It remains unknown if manipulating peak loading influences joint tissue biochemistry. Thus, the purpose of this study is to determine whether manipulating peak vertical ground reaction force (vGRF) during gait influences changes in serum cartilage oligomeric matrix protein (sCOMP) concentrations in ACLR participants.

METHODS

Forty ACLR individuals participated in this randomized crossover study (48% female, age = 21.0 ± 4.4 years, BMI = 24.6 ± 3.1). Participants attended four sessions, wherein they completed one of four biofeedback conditions (habitual loading (no biofeedback), high loading (5% increase in vGRF), low loading (5% decrease in vGRF), and symmetrical loading (between-limb symmetry in vGRF)) while walking on a treadmill for 3000 steps. Serum was collected before (baseline), immediately (acute post), 1 h (1 h post), and 3.5 h (3.5 h post) following each condition. A comprehensive general linear mixed model was constructed to address the differences in sCOMP across all conditions and timepoints in all participants and a subgroup of sCOMP Increasers.

RESULTS

No sCOMP differences were found across the entire cohort. In the sCOMP Increasers, a significant time × condition interaction was found (F9,206 = 2.6, p = 0.009). sCOMP was lower during high loading than low loading (p = 0.009) acutely (acute post). At 3.5 h post, sCOMP was higher during habitual loading than symmetrical loading (p = 0.001).

CONCLUSION

These data suggest that manipulating lower limb loading in ACLR patients who habitually exhibit an acute increase in sCOMP following walking results in improved biochemical changes linked to cartilage health. Key Points • This study assesses the mechanistic link between lower limb load modification and joint tissue biochemistry at acute and delayed timepoints. • Real-time biofeedback provides a paradigm to experimentally assess the mechanistic link between loading and serum biomarkers. • Manipulating peak loading during gait resulted in a metabolic effect of lower sCOMP concentrations in a subgroup of ACLR individuals. • Peak loading modifications may provide an intervention strategy to mitigate the development of PTOA following ACLR.

Effect of Hind- and Fore-Foot Eversion on Positional and Rotational Displacement of the Knee in Standing Posture

We investigated the effects of hindfoot and forefoot eversion on the knee's positional and rotational displacement, plantar pressure, and foot discomfort in a standing posture, beyond the traditional focus on external knee adduction moments (EKAM) in lateral wedge insoles. Twenty-six healthy participants underwent hindfoot eversion from 0 to 10 degrees in 2-degree increments, and forefoot eversion from 0 degrees to the hindfoot eversion angle in 2-degree increments in a standing posture. At each eversion angle, the knee's medial displacement, EKAM's moment arm decrease, plantar pressure changes, and foot discomfort were obtained and compared across varying angles. Both hindfoot-only and entire-foot eversion led to significant medial knee displacement and the EKAM's moment arm decrease, with more pronounced effects in entire-foot eversion. At each hindfoot eversion angle, increasing forefoot eversion resulted in significant medial knee displacement and EKAM's moment arm decrease. Lower leg rotations were not significantly affected in hindfoot-only eversion but displayed significant medial tilting and internal rotation in entire-foot eversion at specific combinations. Varying eversion angles significantly influenced the forefoot pressure, with heel pressure remaining unaffected. Notably, the lateral forefoot pressure increased significantly as the forefoot eversion angle increased, particularly at higher hindfoot eversion angles. Foot discomfort increased significantly with higher eversion angles, particularly in entire-foot eversion, and also increased significantly as the forefoot eversion angle increased at higher hindfoot eversion angles. Insole configurations incorporating 6-10 degrees of hindfoot eversion and 40-60% forefoot eversion of the hindfoot angle may offer optimized biomechanical support for knee osteoarthritis patients.