Foot Posture as a Biomechanical Outcome Measure Following Total Knee Arthroplasty in Individuals with Severe Knee Osteoarthritis

Foot Posture as a Biomechanical Outcome Measure Following Total Knee Arthroplasty in Individuals with Severe Knee Osteoarthritis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Foot Posture as a Biomechanical Outcome Measure Following Total Knee Arthroplasty in Individuals with Severe Knee Osteoarthritis Saidan Shetty, Mohandas Rao KG, Sandeep Vijayan, G Arun Maiya, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7307384/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 05 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted 15 You are reading this latest preprint version Abstract Total knee arthroplasty (TKA) is commonly performed to relieve pain and improve knee function in individuals with severe knee osteoarthritis (OA). Abnormal foot mechanics can influence overall biomechanics and affect post-surgical outcomes. This study aimed to evaluate foot posture as a biomechanical outcome before and after TKA and to explore its relationship with pain and lower extremity function. Seventy-seven individuals with knee OA who underwent TKA, and 77 healthy controls were assessed. Foot posture was measured using the Foot Posture Index (FPI), pain using the Numerical Pain Rating Scale (NPRS), and function using the Lower Extremity Functional Scale (LEFS). Assessments were conducted preoperatively and at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Preoperative FPI scores were significantly higher in the OA group than in controls (1.52 ± 2.5 vs. 0.70 ± 2.2; p = 0.03), indicating a more pronated foot posture. FPI scores did not significantly change throughout the follow-up period. At 6 months post-TKA, FPI remained higher than controls (p = 0.03), but the difference was not significant at 12 months (p = 0.12). A weak positive correlation was found between FPI and NPRS (r = 0.2; p < 0.05), but no correlation was observed with LEFS. Foot posture evaluation may support comprehensive rehabilitation planning after TKA. Health sciences/Diseases Health sciences/Health care Health sciences/Medical research Health sciences/Rheumatology foot posture total knee arthroplasty total knee replacement knee osteoarthritis Figures Figure 1 Figure 2 Introduction Knee osteoarthritis (OA) is a progressive musculoskeletal condition characterized by the degeneration of joint structures, including articular cartilage, subchondral bone, menisci, and surrounding soft tissues. These pathological changes often manifest clinically as joint pain, swelling, stiffness, and reduced range of motion, significantly affecting functional mobility and quality of life 1 – 3 . In advanced stages of knee OA, patients frequently present with lower limb malalignment, muscle weakness, and joint instability, contributing to altered movement patterns and increased mechanical stress on surrounding joints 4 , 5 . One such area of compensatory adaptation is the foot, which plays a critical role in maintaining posture, balance, and dynamic alignment of the lower extremity 6 – 8 . The foot acts as the terminal base of support for the lower limb kinetic chain. Its posture and alignment can significantly influence, and be influenced by, proximal joint mechanics, particularly in the presence of deformities or pathologies such as knee OA. Alterations in foot posture including increased pronation, supination, or midfoot collapse, are often observed in individuals with varus or valgus knee deformities, as the foot adapts to maintain overall balance and stability. Such compensation, although functional in the short term, may lead to long-term biomechanical inefficiencies, increased energy expenditure during ambulation, and the development of secondary joint problems in the ankle, hip, or spine 9 – 11 . Total knee arthroplasty (TKA) is widely considered the gold standard surgical intervention for end-stage knee OA when conservative measures fail to provide relief. TKA aims to correct joint deformity, relieve pain, and restore function 12 , 13 . However, while much focus has been placed on changes in limb alignment around the knee post-surgery, less attention has been given to the biomechanical outcomes in distal joints such as the foot. Despite successful surgical correction of knee alignment, compensatory foot postural changes that develop preoperatively may persist or undergo further adaptation, potentially impacting overall rehabilitation outcomes and long-term joint health 7 , 10 . Foot posture serves as a clinically accessible and biomechanically relevant indicator of lower limb alignment and weight-bearing distribution. The use of standardized assessment tools, such as the Foot Posture Index (FPI), allows for objective evaluation of foot structure in multiple planes 14 . Given the kinetic chain relationship between the hip, knee, and foot, postural adaptations in the foot could reflect changes in limb alignment following TKA, thus providing insight into the structural integrity and functional restoration achieved through surgical and rehabilitative interventions. Moreover, abnormal foot posture may be associated with altered gait mechanics, increased joint loading, and persistent discomfort even after TKA, highlighting the need for its inclusion as a postoperative assessment parameter 6 , 9 , 10 . To date, few studies have evaluated foot posture as a biomechanical outcome measure following TKA. Understanding how foot posture responds to surgical realignment of the knee could offer valuable perspectives on broader biomechanical adaptations of the lower limb. These findings may also assist in guiding targeted therapeutic strategies to optimize rehabilitation and prevent compensatory overuse injuries. Hence, the objective of this study was to assess foot posture as an outcome measure of biomechanical adaptation before and after TKA and to examine its correlation with pain and lower extremity function after TKA in individuals with severe knee OA. Materials and Methods Study design and participants This is a pre-post study design performed at the Department of Physiotherapy and Department of Orthopaedics, Kasturba Hospital, Manipal, Karnataka, India. Ethical approval was sought by the Institutional Ethics Committee (IEC) of Kasturba Hospital, Manipal (IEC1–20 − 2022). The study protocol was registered in the Clinical Trial Registry – India (CTRI/2022/07/043642). The study was performed as per the World Medical Association (Declaration of Helsinki) - Code of Ethics. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were followed 15 . Seventy-seven participants with severe knee OA who underwent TKA, and seventy-seven healthy controls were recruited to compare the TKA data. The sample size was calculated using the formula n = (Z₁₋⍺/2)² × σ² / d², assuming Z = 1.96 (95% CI), SD = 16, and minimal clinically relevant difference = 4. This yielded a required sample of 61, increased to 77 accounting for 20% attrition. The sample size for age- and sex-matched control group was n = 77 16 . The inclusion criterion for the TKA group was patients aged 50–80 years of either sex with primary severe (Kellgren–Lawrence grade 4) knee OA who were scheduled for TKA using the medial parapatellar approach. The inclusion criteria for the control group were healthy individuals who did not have any current lower extremity orthopedic injuries or neurological, immunological, inflammatory, or cardiovascular diseases and were aged 50–80 years of either sex. Individuals who had inflammatory arthritis with multiple joint involvement, neurological deficits, or posttraumatic arthritis and those who declined to participate were excluded from the study 16 . Instrumentation and procedure The screening of the participants was performed as per the eligibility criteria. The demographic information of the participants, including age (in years), sex, height (in cm), weight (in kg), and body mass index (BMI) (in kg/m2), was collected. The participants were informed about the procedure of the study, and their consent was acquired. The outcomes were assessed by a musculoskeletal physical therapist with clinical experience in knee assessment and rehabilitation. Foot posture, pain and lower extremity function were assessed using relevant clinical scales. Measurements were taken preoperatively (one day before surgery) and at the 6th week, 3rd month, 6th month and 12th month following TKA 16 . Intervention program All the participants underwent a standard postoperative TKA rehabilitation program post-TKA 17 , 18 . The standard rehabilitation programme consisted of strengthening exercises, mobility-based and stretching exercises, functional training, balance training, and aerobic conditioning. The stage 1 exercises were administered from day 1 to 2 weeks in the early function phase following TKA. Stage 2 exercises were administered in the progressive function phase from 3–6 weeks following TKA. Stage 3 exercises were administered in the advanced function phase from 7–12 weeks following TKA. The rehabilitation exercises progressed according to the postoperative stages 17 . Foot posture assessment before and after TKA The Foot Posture Index (FPI) is a clinical tool used to assess the overall posture of the foot in the standing position. The assessment involved observing and scoring six criteria: talar head palpation, curves above and below the lateral malleoli, inversion/eversion of the calcaneus, bulging in the region of the talonavicular joint, congruence of the medial longitudinal arch, and abduction/adduction of the forefoot on the rearfoot. Each criterion is scored on a scale from − 2 (indicative of a supinated foot) to + 2 (indicative of a pronated foot), with a total score ranging from − 12 to + 12. The patient stood relaxed in a natural posture while the therapist evaluated each component (Fig. 1 ). The cumulative Foot Posture Index (FPI) score classifies the foot as highly supinated (–12 to − 5), supinated (–4 to − 1), neutral (0 to + 5), pronated (+ 6 to + 9), or highly pronated (+ 10 to + 12), aiding in diagnosis and treatment planning 14 , 19 . Pain and lower extremity function assessment before and after TKA Pain severity was evaluated using the Numerical Pain Rating Scale (NPRS), which ranges from 0–10, with scores ranging from 0 (no pain) to 10 (worst pain possible) 20 , 21 . This scale has been shown to be reliable in OA, and is recommended for use in knee OA clinical trials 22 , 23 . The Lower Extremity Functional Scale (LEFS) was used to assess patients' initial function, track their progress, and evaluate outcomes in individuals with lower extremity impairments. It has excellent internal reliability (α = 0.96) 24 . Statistical analysis The data were analyzed using Jamovi 2.6.23. Demographic characteristics were summarized using descriptive statistics. The values of the FPIs obtained are shown as the means and standard deviations (SDs). Kruskal-Wallis ANOVA was performed to compare the FPI scores before TKA, and at the 6th week, 3rd month, 6th month and 12th month after TKA. The correlations of the FPI score with pain were determined using Spearman’s correlation coefficient. The level of statistical significance was set as p ≤ 0.05. Results Demographics Seventy-seven individuals (47 females and 30 males) with severe knee OA, with a mean age of 66.93 (SD = 7.1) years and 77 healthy controls (45 females and 32 males), with a mean age of 62.78 (SD = 9.64) years, were included in the study. The mean duration of knee pain was 15.9 (SD = 4.3) months. The demographic details are shown in Table 1 . Table 1 Demographic & anthropometric characteristics of TKA group and control group participants Variables TKA group (n = 77) Control group (n = 77) Age (in years) (Mean ± SD) 66.93 ± 7.1 62.78 ± 9.64 Gender (Female, Male) Females (n, %) 47 (61.03%) 45 (58.44%) Males (n, %) 30 (38.96%) 32 (41.55%) Height (in cm) (Mean ± SD) 155.8 ± 8.45 157.43 ± 6.12 Weight (in kg) (Mean ± SD) 69.21 ± 14.1 65.8 ± 12.32 BMI (in kg/m2) (Mean ± SD) 28.36 ± 11.3 25.78 ± 10.21 Leg dominance (Right, Left) Right (n, %) 72 (93.5%) 69 (89.64%) Left (n, %) 5 (6.49%) 8 (10.38%) *TKA: Total Knee Arthroplasty; cm: centimeter; kg: kilogram; BMI: Body Mass Index; SD: Standard Deviation Comparison of FPI scores between individuals with knee OA and healthy controls The mean FPI score was 1.52 (SD = 2.5) in individuals with knee OA before TKA and 0.70 (SD = 2.2) in healthy controls. A significant (p = 0.03) difference was noted between the FPI scores of individuals with knee OA and healthy controls. Compared with controls, individuals with knee OA demonstrated mild to moderately pronated foot in the FPI. (Table 2.1 ) (Fig. 2 ). Comparison of FPI scores in individuals with knee OA before and after TKA The mean FPI score was 1.52 (SD = 2.5) in individuals with knee OA before TKA. Post-TKA, the mean FPI score was 1.56 (SD = 2.9) at the 6th week, 1.58 (SD = 2.7) at the 3rd month, 1.54 (SD = 2.15) at the 6th month and 1.5 (SD = 2.26) at the 12th month. No significant difference was noted between the FPI score in individuals with knee OA before TKA and at follow-up timepoints after TKA (Table 2.2 ). Table 2.2 FPI scores for pre-TKA and post-TKA Outcome measure Pre-TKA (n = 77) Post-TKA – 6th w (n = 77) Post-TKA – 3rd m (n = 77) Post-TKA – 6th m (n = 54) Post-TKA – 12th m (n = 28) p-value FPI 1.52 ± 2.5 1.56 ± 2.9 1.58 ± 2.71 1.54 ± 2.15 1.5 ± 2.26 0.06 *Significant at p ≤ 0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; FPI: foot posture index Comparison of FPI scores between individuals with knee OA after TKA and healthy controls The mean FPI score was 1.54 (SD = 2.15) in individuals with knee OA 6 months after TKA, 1.5 (SD = 2.26) 12 months after TKA and 0.70 (SD = 2.2) in healthy controls. A significant difference (p = 0.03) was noted between the FPI score at the 6th month after TKA in individuals with knee OA and healthy controls. However, there was no significant difference noted between the FPI score at the 12th month after TKA (Table 2.3 ). Table 2.3 FPI scores for post-TKA and control groups Outcome measure Controls (n = 77) Post-TKA – MD 95% CI % Change p - value FPI 0.70 ± 2.2 1.54 ± 2.15 (6th m, n = 54) −0.84 [− 1.60, − 0.08] 54.55% (At 6th m) 0.03* 0.70 ± 2.2 1.5 ± 2.26 (12th m, n = 26) −0.80 [− 1.80, 0.20] 53.33% (At 12th m) 0.12 *Significant at p ≤ 0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; FPI: foot posture index Correlation of the FPI score with pain and function in individuals with knee OA following TKA Pain levels demonstrated a consistent and significant reduction following TKA (7.97 ± 2.48 to 2.36 ± 1.45, p < 0.001) (Table 3.1 ). Compared to the preoperative mean NPRS score of 7.97, pain decreased by approximately 46.3% at the 5th postoperative day, 52.8% at the 6th week, 57.8% at the 3rd month, 64.0% at the 6th month, and 70.4% at the 12th month, indicating progressive and sustained pain relief over time (p < 0.001). Functional performance, as assessed by the LEFS, showed notable improvement post-TKA (24.75 ± 6.28 to 60.25 ± 5.1, p < 0.001) (Table 3.2 ). The mean LEFS score increased from a baseline of 24.75 to 32.2 at the 6th week (a 30.1% increase), 46.8 at the 3rd month (an 89.1% increase), 58.5 at the 6th month (a 136.4% increase), and 60.25 at the 12th month (a 143.4% increase), reflecting a substantial and sustained functional recovery (p < 0.001). A weak linear correlation (r = 0.2; p < 0.05) was noted between the FPI score and pain following TKA suggesting a small effect size. No significant correlation was found between the FPI and LEFS scores. Table 3.1 Pain scores for pre-TKA and post-TKA Outcome measure Pre-TKA (n = 77) Post-TKA – 5th d (n = 77) Post-TKA – 6th w (n = 77) Post-TKA – 3rd m (n = 77) Post-TKA – 6th m (n = 77) Post-TKA – 12th m (n = 77) p-value NPRS 7.97 ± 2.48 4.28 ± 1.26 3.76 ± 1.4 3.36 ± 1.40 2.87 ± 1.36 2.36 ± 1.45 < 0.001 SD: standard deviation; TKA: total knee arthroplasty; NPRS: numerical pain rating scale; d: day; w: week; m: month Table 3.2 LEFS scores for pre-TKA and post-TKA Outcome measures Pre-TKA (n = 77) Post-TKA – 6th w (n = 77) Post-TKA – 3rd m (n = 77) Post-TKA – 6th m (n = 54) Post-TKA – 12th m (n = 28) p-value LEFS 24.75 ± 6.28 32.2 ± 7.1 46.8 ± 6.9 58.5 ± 5.8 60.25 ± 5.1 < 0.001* * Significant at p ≤ 0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; LEFS: lower extremity functional scale Discussion The objective of this study was to evaluate foot posture as an outcome measure before and after TKA in individuals with severe knee OA and to determine the correlation of the FPI score with pain and function following TKA. Clinical measurement of foot posture before and after TKA The significant difference in FPI scores between individuals with knee OA and healthy controls suggests that chronic knee joint degeneration may influence foot posture. Specifically, the higher FPI scores in individuals with OA than in healthy individuals indicate a tendency toward a mild to moderately pronated foot posture, which is in line with previous reports 14 , 25 , 26 and reflects compensatory biomechanical strategies developed over time to reduce pain and to maintain mobility. A pronated foot posture may help in shock absorption and load redistribution, especially in the presence of altered knee joint mechanics and pain-driven gait changes associated with OA 26 – 28 . Interestingly, despite undergoing TKA, there was no statistically significant change in FPI scores at any postoperative time point up to 12 months, indicating that surgical correction of the knee alone may not be sufficient to influence established foot posture. This finding may reflect the persistence of neuromuscular adaptations and learned movement patterns developed during the chronic phase of OA, which are not automatically reversed with surgical intervention 7 , 29 , 30 . However, the reduced number of participants at later follow-ups may have limited the ability to detect subtle longitudinal changes. Several factors could explain why foot posture remains altered following TKA. First, while TKA addresses structural and functional issues at the knee joint, it does not directly target the foot or ankle complex. Chronic adaptations in the foot, such as ligamentous laxity or altered muscle activation, may persist unless they are specifically addressed through rehabilitation 7 , 31 . Furthermore, the duration of preoperative symptoms, which averaged nearly 16 months, may contribute to the entrenchment of compensatory mechanisms that are slow to change, even with improved knee function and reduced pain. Even 12 months after TKA, FPI scores differ significantly between individuals with knee OA and healthy controls, suggesting that foot posture may remain unaffected by surgical correction of the knee joint. This highlights the need to recognize and manage secondary musculoskeletal adaptations, such as altered foot posture, that may persist despite successful knee realignment 27 , 28 , 32 . Correlation of FPI scores with pain and function following TKA Although pain significantly improved after TKA, the weak correlation between FPI scores and pain suggests that pain relief alone does not directly translate to normalization of foot posture. Additionally, no significant correlation was found between FPI and functional performance as measured by the LEFS score, indicating that improvements in functional ability post-TKA may occur independently of changes in foot posture. This may be attributed to the fact that functional recovery is influenced by multiple factors, including muscle strength, joint stability, proprioception, and patient engagement in rehabilitation, rather than static foot alignment alone. These findings highlight the importance of addressing foot posture and gait mechanics through comprehensive rehabilitation programs that go beyond knee joint recovery, particularly in patients exhibiting persistent postural deviations despite surgical intervention 31 , 33 , 34 . These findings suggest that knee OA is associated with a more pronated foot posture, which does not significantly change following TKA, even with substantial pain reduction. This could be due to long-standing neuromuscular and biomechanical adaptations that persist unless specifically targeted. Strategies can be developed to improve foot posture, restore lower limb biomechanics, and enhance long-term function. Clinical implications This study offers important clinical insights into the persistence of altered foot posture following TKA in individuals with knee OA. The findings highlight the value of using accessible and clinically feasible tools such as the FPI to monitor lower limb alignment beyond the knee joint. Although TKA effectively improves joint structure, relieves pain, and enhances function, our results suggest that associated compensatory changes in foot posture particularly a tendency toward pronation may not resolve postoperatively without specific intervention. These persistent postural alterations may contribute to inefficient gait mechanics or uneven load distribution, even after successful surgical correction. This underscores the importance of a holistic, kinetic-chain-based approach in post-TKA rehabilitation, one that considers the interdependent nature of the lower extremity kinetic chain. Clinical evaluation should be routinely extended to the foot and ankle, not only for diagnostic purposes but also to inform targeted rehabilitation planning. Rehabilitation programs following TKA should incorporate strategies aimed at improving foot and ankle function, including strengthening exercises, neuromuscular control training, and gait retraining. In cases of persistent foot misalignment, the use of orthotics or supportive footwear may also be beneficial. Such comprehensive interventions can promote better biomechanical efficiency and potentially reduce the risk of secondary complications or future joint strain. Moreover, the lack of a strong correlation between foot posture and improvements in pain or function highlights that traditional outcome measures may not fully capture the scope of biomechanical adaptation. Therefore, integrating FPI assessment with routine follow-up could serve as an additional metric for identifying individuals who may benefit from extended or specialized rehabilitation. Overall, these findings support a more integrated and personalized approach to post-TKA care, one that addresses not only pain and mobility at the knee, but also the functional alignment of the entire lower limb to optimize long-term outcomes and patient quality of life. Limitations The reduction in sample size at the 6th (n = 54) and 12th (n = 28) months post-TKA follow-up, due to participant attrition, may have limited the statistical power of the study and restricted the generalizability of the findings, particularly regarding the longitudinal interpretation of FPI, pain, and function trends. Although the FPI is a reliable and clinically feasible tool, it is semiquantitative and subject to interrater variability, which could have introduced measurement bias. Additionally, the study did not account for potential confounding factors such as differences in rehabilitation protocols, footwear habits, or physical activity levels, all of which may influence foot posture independent of surgical correction. Future recommendations Future studies may explore the relationship between foot posture and lower limb alignment parameters such as the hip-knee-ankle (HKA) angle or tibial torsion to provide a more comprehensive understanding of compensatory biomechanical adaptations post-TKA. Additionally, long-term follow-up beyond 12 months could offer valuable insights into whether persistent changes in foot posture stabilize, worsen, or improve over time. Future rehabilitation protocols following TKA should consider routine foot posture assessments and address compensatory postural changes. Further research incorporating objective measures such as 3D gait analysis, plantar pressure distribution, or dynamic balance testing may help correlate foot posture alterations with functional gait outcomes. Studies evaluating the effectiveness of specific post-TKA rehabilitation strategies, including foot orthoses, gait retraining, and ankle-foot strengthening, could also help inform evidence-based clinical guidelines for enhancing recovery, optimizing lower limb biomechanics and improving long-term functional outcomes. Conclusions The present study highlights the role of foot posture as an important outcome measure of biomechanical adaptation in individuals with severe knee OA before and after TKA. Significant differences in FPI scores were observed between individuals with knee OA and healthy controls. However, no significant change was observed in the FPI scores in individuals with knee OA before and after TKA indicating persistent foot posture deviations. A weak linear correlation was observed between the FPI score and pain following TKA, whereas no significant correlation was found with functional performance. Understanding foot posture changes and their relationships with clinical and functional variables is essential in post-TKA rehabilitation planning. Incorporating foot posture assessment into routine clinical practice may enhance the overall recovery process and contribute to long-term functional outcomes. Abbreviations OA Osteoarthritis TKA Total Knee Arthroplasty FPI Foot Posture Index IEC Institutional Ethics Committee CTRI Clinical Trial Registry – India STROBE Strengthening the Reporting of Observational studies in Epidemiology cm Centimetre kg Kilogram kg/m2 Kilogram per meter square BMI Body Mass Index NPRS Numerical Pain Rating Scale LEFS Lower Extremity Functional Scale Declarations Ethics approval and consent to participate The Institutional Ethics Committee (IEC) of the tertiary care hospital provided ethical approval (IEC1 - 20 - 2022). This study was conducted in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki). The study protocol was registered with the Clinical Trial Registry-India (CTRI/2022/07/043642). Consent for publication Written informed consent was obtained from all participants for the publication of any identifying images or clinical data included in this manuscript. All participants were informed that their information and images may be published in a scientific journal and that their identities would be protected to the fullest extent possible. Data availability statement The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Authors’ contributions SS conceptualized and designed the study, prepared initial protocol, performed IEC registration and CTRI registration, conducted the methodology, data collection and data analysis and writing of the manuscript. MRKG performed theformal analysis, review & editing of the manuscript, and overall supervision. SV performed the formal analysis, review & editing of the manuscript, and overall supervision. GAM performed the formal analysis, review & editing of the manuscript, and overall supervision. BMG performed the formal analysis, review & editing of the manuscript, and overall supervision. All authors read and approved the final manuscript. Acknowledgements The authors would like to acknowledge the participants for their time and voluntary participation in this study. The authors would like to thank the Manipal Academy of Higher Education (MAHE) for providing all the support and resources for the conduct of this study. References Krasnokutsky, S., Attur, M., Palmer, G., Samuels, J. & Abramson, S. B. Current concepts in the pathogenesis of osteoarthritis. Osteoarthritis Cartilage 16 , S1–S3 (2008). Vitaloni, M. et al. Global management of patients with knee osteoarthritis begins with quality of life assessment: a systematic review. BMC Musculoskelet Disord 20 , 493 (2019). Nelson, A. E. Osteoarthritis year in review 2017: clinical. Osteoarthritis Cartilage 26 , 319–325 (2018). 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M., Snyder-Mackler, L. & Stevens-Lapsley, J. E. Total Knee Arthroplasty Assessments Should Include Strength and Performance-Based Functional Tests to Complement Range-of-Motion and Patient-Reported Outcome Measures. Phys Ther 102 , (2022). Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 05 Dec, 2025 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 06 Nov, 2025 Reviews received at journal 29 Oct, 2025 Reviews received at journal 14 Oct, 2025 Reviews received at journal 11 Oct, 2025 Reviewers agreed at journal 09 Oct, 2025 Reviewers agreed at journal 08 Oct, 2025 Reviewers agreed at journal 08 Oct, 2025 Reviews received at journal 06 Sep, 2025 Reviewers agreed at journal 05 Sep, 2025 Reviewers agreed at journal 03 Sep, 2025 Reviewers invited by journal 16 Aug, 2025 Editor assigned by journal 16 Aug, 2025 Editor invited by journal 11 Aug, 2025 Submission checks completed at journal 08 Aug, 2025 First submitted to journal 08 Aug, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7307384","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":502632917,"identity":"d3584511-04cb-42c8-903b-2020e1a10fe9","order_by":0,"name":"Saidan Shetty","email":"","orcid":"","institution":"Department of Anatomy, Melaka Manipal Medical College - Manipal Campus, Manipal Academy of Higher Education (MAHE), Manipal- 576104, Karnataka, India","correspondingAuthor":false,"prefix":"","firstName":"Saidan","middleName":"","lastName":"Shetty","suffix":""},{"id":502632918,"identity":"6bb8a0cc-e228-4aa1-a6cd-3eaa69f99047","order_by":1,"name":"Mohandas Rao KG","email":"","orcid":"","institution":"Division of Anatomy, Department of Basic Medical Sciences, Manipal Academy of Higher Education (MAHE), Manipal- 576104, Karnataka, India","correspondingAuthor":false,"prefix":"","firstName":"Mohandas","middleName":"Rao","lastName":"KG","suffix":""},{"id":502632919,"identity":"909614bf-29c5-4388-8414-d9f512067893","order_by":2,"name":"Sandeep Vijayan","email":"","orcid":"","institution":"Department of Orthopaedics, Kasturba Medical College (KMC) Manipal, Manipal Academy of Higher Education (MAHE), Manipal- 576104, Karnataka, India","correspondingAuthor":false,"prefix":"","firstName":"Sandeep","middleName":"","lastName":"Vijayan","suffix":""},{"id":502632920,"identity":"e4b214bf-5096-48b3-b967-7cde1483b753","order_by":3,"name":"G Arun Maiya","email":"","orcid":"","institution":"Department of Physiotherapy, Centre for Podiatry \u0026 Diabetic Foot Care and Research, Manipal College of Health Professions (MCHP), Manipal Academy of Higher Education (MAHE)","correspondingAuthor":false,"prefix":"","firstName":"G","middleName":"Arun","lastName":"Maiya","suffix":""},{"id":502632921,"identity":"5e765d73-8729-40f5-b706-66971480332d","order_by":4,"name":"Bincy M George","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEUlEQVRIiWNgGAWjYBACA2Zk3gcgZmNgYDzAwMCMXT26FsYZEC0M+LUgc5h5oAy8WszZeQ9+5mGoleOXPn7xsW2OXR6fdPODAwwV1okNOLRYNvMlS/MwHDeW7MspNs7dllzMJnPM4ADDmXScWgwO85gB3XMsccMZnjTp3G3MiW0SCQYHGNsOE9RSD9SS/ttyWz1QS/qHA4z/CGqpSTA4w36MmXHbYaCWHKAtDbi1WDbzGEvOMThgOLOHh1myd9vxxDaZMwUHEo6lG+PSYs5/xvDDm4o6eX4e9ocffm6rTpw/u33jgw811rK4tIAAE4/BYSDFA40jCSBOwKMcBBh/MNQBKfYHCC2jYBSMglEwCpAAABS2V19Vyr0gAAAAAElFTkSuQmCC","orcid":"","institution":"Division of Anatomy, Department of Basic Medical Sciences, Manipal Academy of Higher Education (MAHE), Manipal- 576104, Karnataka, India","correspondingAuthor":true,"prefix":"","firstName":"Bincy","middleName":"M","lastName":"George","suffix":""}],"badges":[],"createdAt":"2025-08-06 08:23:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7307384/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7307384/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-31351-0","type":"published","date":"2025-12-05T15:57:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":89840173,"identity":"9dd74fb6-4de2-4e3f-a05f-3469577cd5ef","added_by":"auto","created_at":"2025-08-25 15:13:08","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":906499,"visible":true,"origin":"","legend":"\u003cp\u003eFPI assessment position for the anterior view, posterior view and lateral views\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7307384/v1/90c8076a1db80a91b7c84740.jpeg"},{"id":89838622,"identity":"3d692da2-3669-49d1-ab0c-89b3226d497a","added_by":"auto","created_at":"2025-08-25 15:05:08","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":50001,"visible":true,"origin":"","legend":"\u003cp\u003eFoot posture assessment in individuals with knee OA\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7307384/v1/82d98337cd229de97844dd3e.jpeg"},{"id":97723896,"identity":"fa0f6969-f3c3-4aa2-ae39-2937aaa6e211","added_by":"auto","created_at":"2025-12-08 16:09:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2046443,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7307384/v1/24615606-47bf-4dc7-8171-0e12cafee0ed.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Foot Posture as a Biomechanical Outcome Measure Following Total Knee Arthroplasty in Individuals with Severe Knee Osteoarthritis","fulltext":[{"header":"Introduction","content":"\u003cp\u003eKnee osteoarthritis (OA) is a progressive musculoskeletal condition characterized by the degeneration of joint structures, including articular cartilage, subchondral bone, menisci, and surrounding soft tissues. These pathological changes often manifest clinically as joint pain, swelling, stiffness, and reduced range of motion, significantly affecting functional mobility and quality of life \u003csup\u003e\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. In advanced stages of knee OA, patients frequently present with lower limb malalignment, muscle weakness, and joint instability, contributing to altered movement patterns and increased mechanical stress on surrounding joints \u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. One such area of compensatory adaptation is the foot, which plays a critical role in maintaining posture, balance, and dynamic alignment of the lower extremity \u003csup\u003e\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe foot acts as the terminal base of support for the lower limb kinetic chain. Its posture and alignment can significantly influence, and be influenced by, proximal joint mechanics, particularly in the presence of deformities or pathologies such as knee OA. Alterations in foot posture including increased pronation, supination, or midfoot collapse, are often observed in individuals with varus or valgus knee deformities, as the foot adapts to maintain overall balance and stability. Such compensation, although functional in the short term, may lead to long-term biomechanical inefficiencies, increased energy expenditure during ambulation, and the development of secondary joint problems in the ankle, hip, or spine \u003csup\u003e\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTotal knee arthroplasty (TKA) is widely considered the gold standard surgical intervention for end-stage knee OA when conservative measures fail to provide relief. TKA aims to correct joint deformity, relieve pain, and restore function \u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e,\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. However, while much focus has been placed on changes in limb alignment around the knee post-surgery, less attention has been given to the biomechanical outcomes in distal joints such as the foot. Despite successful surgical correction of knee alignment, compensatory foot postural changes that develop preoperatively may persist or undergo further adaptation, potentially impacting overall rehabilitation outcomes and long-term joint health \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eFoot posture serves as a clinically accessible and biomechanically relevant indicator of lower limb alignment and weight-bearing distribution. The use of standardized assessment tools, such as the Foot Posture Index (FPI), allows for objective evaluation of foot structure in multiple planes \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Given the kinetic chain relationship between the hip, knee, and foot, postural adaptations in the foot could reflect changes in limb alignment following TKA, thus providing insight into the structural integrity and functional restoration achieved through surgical and rehabilitative interventions. Moreover, abnormal foot posture may be associated with altered gait mechanics, increased joint loading, and persistent discomfort even after TKA, highlighting the need for its inclusion as a postoperative assessment parameter \u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTo date, few studies have evaluated foot posture as a biomechanical outcome measure following TKA. Understanding how foot posture responds to surgical realignment of the knee could offer valuable perspectives on broader biomechanical adaptations of the lower limb. These findings may also assist in guiding targeted therapeutic strategies to optimize rehabilitation and prevent compensatory overuse injuries. Hence, the objective of this study was to assess foot posture as an outcome measure of biomechanical adaptation before and after TKA and to examine its correlation with pain and lower extremity function after TKA in individuals with severe knee OA.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy design and participants\u003c/h2\u003e\u003cp\u003eThis is a pre-post study design performed at the Department of Physiotherapy and Department of Orthopaedics, Kasturba Hospital, Manipal, Karnataka, India. Ethical approval was sought by the Institutional Ethics Committee (IEC) of Kasturba Hospital, Manipal (IEC1\u0026ndash;20 \u0026minus;\u0026thinsp;2022). The study protocol was registered in the Clinical Trial Registry \u0026ndash; India (CTRI/2022/07/043642). The study was performed as per the World Medical Association (Declaration of Helsinki) - Code of Ethics. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were followed \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eSeventy-seven participants with severe knee OA who underwent TKA, and seventy-seven healthy controls were recruited to compare the TKA data. The sample size was calculated using the formula n = (Z₁₋⍺/2)\u0026sup2; \u0026times; σ\u0026sup2; / d\u0026sup2;, assuming Z\u0026thinsp;=\u0026thinsp;1.96 (95% CI), SD\u0026thinsp;=\u0026thinsp;16, and minimal clinically relevant difference\u0026thinsp;=\u0026thinsp;4. This yielded a required sample of 61, increased to 77 accounting for 20% attrition. The sample size for age- and sex-matched control group was n\u0026thinsp;=\u0026thinsp;77 \u003csup\u003e16\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe inclusion criterion for the TKA group was patients aged 50\u0026ndash;80 years of either sex with primary severe (Kellgren\u0026ndash;Lawrence grade 4) knee OA who were scheduled for TKA using the medial parapatellar approach. The inclusion criteria for the control group were healthy individuals who did not have any current lower extremity orthopedic injuries or neurological, immunological, inflammatory, or cardiovascular diseases and were aged 50\u0026ndash;80 years of either sex. Individuals who had inflammatory arthritis with multiple joint involvement, neurological deficits, or posttraumatic arthritis and those who declined to participate were excluded from the study \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eInstrumentation and procedure\u003c/h3\u003e\n\u003cp\u003eThe screening of the participants was performed as per the eligibility criteria. The demographic information of the participants, including age (in years), sex, height (in cm), weight (in kg), and body mass index (BMI) (in kg/m2), was collected. The participants were informed about the procedure of the study, and their consent was acquired. The outcomes were assessed by a musculoskeletal physical therapist with clinical experience in knee assessment and rehabilitation. Foot posture, pain and lower extremity function were assessed using relevant clinical scales. Measurements were taken preoperatively (one day before surgery) and at the 6th week, 3rd month, 6th month and 12th month following TKA \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003ch3\u003eIntervention program\u003c/h3\u003e\n\u003cp\u003eAll the participants underwent a standard postoperative TKA rehabilitation program post-TKA \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e,\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. The standard rehabilitation programme consisted of strengthening exercises, mobility-based and stretching exercises, functional training, balance training, and aerobic conditioning. The stage 1 exercises were administered from day 1 to 2 weeks in the early function phase following TKA. Stage 2 exercises were administered in the progressive function phase from 3\u0026ndash;6 weeks following TKA. Stage 3 exercises were administered in the advanced function phase from 7\u0026ndash;12 weeks following TKA. The rehabilitation exercises progressed according to the postoperative stages \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\n\u003ch3\u003eFoot posture assessment before and after TKA\u003c/h3\u003e\n\u003cp\u003eThe Foot Posture Index (FPI) is a clinical tool used to assess the overall posture of the foot in the standing position. The assessment involved observing and scoring six criteria: talar head palpation, curves above and below the lateral malleoli, inversion/eversion of the calcaneus, bulging in the region of the talonavicular joint, congruence of the medial longitudinal arch, and abduction/adduction of the forefoot on the rearfoot. Each criterion is scored on a scale from \u0026minus;\u0026thinsp;2 (indicative of a supinated foot) to +\u0026thinsp;2 (indicative of a pronated foot), with a total score ranging from \u0026minus;\u0026thinsp;12 to +\u0026thinsp;12. The patient stood relaxed in a natural posture while the therapist evaluated each component (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The cumulative Foot Posture Index (FPI) score classifies the foot as highly supinated (\u0026ndash;12 to \u0026minus;\u0026thinsp;5), supinated (\u0026ndash;4 to \u0026minus;\u0026thinsp;1), neutral (0 to +\u0026thinsp;5), pronated (+\u0026thinsp;6 to +\u0026thinsp;9), or highly pronated (+\u0026thinsp;10 to +\u0026thinsp;12), aiding in diagnosis and treatment planning \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003ePain and lower extremity function assessment before and after TKA\u003c/h3\u003e\n\u003cp\u003ePain severity was evaluated using the Numerical Pain Rating Scale (NPRS), which ranges from 0\u0026ndash;10, with scores ranging from 0 (no pain) to 10 (worst pain possible) \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e,\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. This scale has been shown to be reliable in OA, and is recommended for use in knee OA clinical trials \u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. The Lower Extremity Functional Scale (LEFS) was used to assess patients' initial function, track their progress, and evaluate outcomes in individuals with lower extremity impairments. It has excellent internal reliability (α\u0026thinsp;=\u0026thinsp;0.96) \u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eThe data were analyzed using Jamovi 2.6.23. Demographic characteristics were summarized using descriptive statistics. The values of the FPIs obtained are shown as the means and standard deviations (SDs). Kruskal-Wallis ANOVA was performed to compare the FPI scores before TKA, and at the 6th week, 3rd month, 6th month and 12th month after TKA. The correlations of the FPI score with pain were determined using Spearman\u0026rsquo;s correlation coefficient. The level of statistical significance was set as p\u0026thinsp;\u0026le;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003eDemographics\u003c/h2\u003e\u003cp\u003eSeventy-seven individuals (47 females and 30 males) with severe knee OA, with a mean age of 66.93 (SD\u0026thinsp;=\u0026thinsp;7.1) years and 77 healthy controls (45 females and 32 males), with a mean age of 62.78 (SD\u0026thinsp;=\u0026thinsp;9.64) years, were included in the study. The mean duration of knee pain was 15.9 (SD\u0026thinsp;=\u0026thinsp;4.3) months. The demographic details are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic \u0026amp; anthropometric characteristics of TKA group and control group participants\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eVariables\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eTKA group (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eControl group (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eAge (in years) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e66.93\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e62.78\u0026thinsp;\u0026plusmn;\u0026thinsp;9.64\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eGender (Female, Male)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFemales (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e47 (61.03%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e45 (58.44%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMales (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e30 (38.96%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e32 (41.55%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eHeight (in cm) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e155.8\u0026thinsp;\u0026plusmn;\u0026thinsp;8.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e157.43\u0026thinsp;\u0026plusmn;\u0026thinsp;6.12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eWeight (in kg) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e69.21\u0026thinsp;\u0026plusmn;\u0026thinsp;14.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e65.8\u0026thinsp;\u0026plusmn;\u0026thinsp;12.32\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e\u003cp\u003eBMI (in kg/m2) (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28.36\u0026thinsp;\u0026plusmn;\u0026thinsp;11.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e25.78\u0026thinsp;\u0026plusmn;\u0026thinsp;10.21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eLeg dominance (Right, Left)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eRight (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e72 (93.5%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e69 (89.64%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLeft (n, %)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5 (6.49%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8 (10.38%)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e*TKA: Total Knee Arthroplasty; cm: centimeter; kg: kilogram; BMI: Body Mass Index; SD: Standard Deviation\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eComparison of FPI scores between individuals with knee OA and healthy controls\u003c/h2\u003e\u003cp\u003eThe mean FPI score was 1.52 (SD\u0026thinsp;=\u0026thinsp;2.5) in individuals with knee OA before TKA and 0.70 (SD\u0026thinsp;=\u0026thinsp;2.2) in healthy controls. A significant (p\u0026thinsp;=\u0026thinsp;0.03) difference was noted between the FPI scores of individuals with knee OA and healthy controls. Compared with controls, individuals with knee OA demonstrated mild to moderately pronated foot in the FPI. (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2.1\u003c/span\u003e) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eComparison of FPI scores in individuals with knee OA before and after TKA\u003c/h2\u003e\u003cp\u003eThe mean FPI score was 1.52 (SD\u0026thinsp;=\u0026thinsp;2.5) in individuals with knee OA before TKA. Post-TKA, the mean FPI score was 1.56 (SD\u0026thinsp;=\u0026thinsp;2.9) at the 6th week, 1.58 (SD\u0026thinsp;=\u0026thinsp;2.7) at the 3rd month, 1.54 (SD\u0026thinsp;=\u0026thinsp;2.15) at the 6th month and 1.5 (SD\u0026thinsp;=\u0026thinsp;2.26) at the 12th month. No significant difference was noted between the FPI score in individuals with knee OA before TKA and at follow-up timepoints after TKA (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e2.2\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2.2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFPI scores for pre-TKA and post-TKA\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutcome measure\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePre-TKA (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th w (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 3rd m (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th m (n\u0026thinsp;=\u0026thinsp;54)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 12th m (n\u0026thinsp;=\u0026thinsp;28)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFPI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.52\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.56\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.58\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;2.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.54\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;2.15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;2.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.06\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"7\"\u003e*Significant at p\u0026thinsp;\u0026le;\u0026thinsp;0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; FPI: foot posture index\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eComparison of FPI scores between individuals with knee OA after TKA and healthy controls\u003c/h2\u003e\u003cp\u003eThe mean FPI score was 1.54 (SD\u0026thinsp;=\u0026thinsp;2.15) in individuals with knee OA 6 months after TKA, 1.5 (SD\u0026thinsp;=\u0026thinsp;2.26) 12 months after TKA and 0.70 (SD\u0026thinsp;=\u0026thinsp;2.2) in healthy controls. A significant difference (p\u0026thinsp;=\u0026thinsp;0.03) was noted between the FPI score at the 6th month after TKA in individuals with knee OA and healthy controls. However, there was no significant difference noted between the FPI score at the 12th month after TKA (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e2.3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2.3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eFPI scores for post-TKA and control groups\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutcome measure\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eControls (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePost-TKA \u0026ndash;\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMD\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003e% Change\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ep - value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003e\u003cb\u003eFPI\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.54\u0026thinsp;\u0026plusmn;\u0026thinsp;2.15\u003c/p\u003e\u003cp\u003e(6th m, n\u0026thinsp;=\u0026thinsp;54)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026minus;0.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026minus;\" colname=\"c5\"\u003e\u003cp\u003e[\u0026minus;\u0026thinsp;1.60, \u0026minus;\u0026thinsp;0.08]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e54.55%\u003c/p\u003e\u003cp\u003e(At 6th m)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.03*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.26\u003c/p\u003e\u003cp\u003e(12th m, n\u0026thinsp;=\u0026thinsp;26)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u0026minus;0.80\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026minus;\" colname=\"c5\"\u003e\u003cp\u003e[\u0026minus;\u0026thinsp;1.80,\u003c/p\u003e\u003cp\u003e0.20]\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e53.33%\u003c/p\u003e\u003cp\u003e(At 12th m)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.12\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"7\"\u003e*Significant at p\u0026thinsp;\u0026le;\u0026thinsp;0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; FPI: foot posture index\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eCorrelation of the FPI score with pain and function in individuals with knee OA following TKA\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePain levels demonstrated a consistent and significant reduction following TKA (7.97\u0026thinsp;\u0026plusmn;\u0026thinsp;2.48 to 2.36\u0026thinsp;\u0026plusmn;\u0026thinsp;1.45, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e3.1\u003c/span\u003e). Compared to the preoperative mean NPRS score of 7.97, pain decreased by approximately 46.3% at the 5th postoperative day, 52.8% at the 6th week, 57.8% at the 3rd month, 64.0% at the 6th month, and 70.4% at the 12th month, indicating progressive and sustained pain relief over time (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Functional performance, as assessed by the LEFS, showed notable improvement post-TKA (24.75\u0026thinsp;\u0026plusmn;\u0026thinsp;6.28 to 60.25\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e3.2\u003c/span\u003e). The mean LEFS score increased from a baseline of 24.75 to 32.2 at the 6th week (a 30.1% increase), 46.8 at the 3rd month (an 89.1% increase), 58.5 at the 6th month (a 136.4% increase), and 60.25 at the 12th month (a 143.4% increase), reflecting a substantial and sustained functional recovery (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). A weak linear correlation (r\u0026thinsp;=\u0026thinsp;0.2; p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) was noted between the FPI score and pain following TKA suggesting a small effect size. No significant correlation was found between the FPI and LEFS scores.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3.1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePain scores for pre-TKA and post-TKA\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutcome measure\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePre-TKA\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 5th d (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th w (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 3rd m (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th m (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 12th m (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNPRS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7.97\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;2.48\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.28\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;1.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.76\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.36\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;1.40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.87\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;1.36\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.36\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;1.45\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eSD: standard deviation; TKA: total knee arthroplasty; NPRS: numerical pain rating scale; d: day; w: week; m: month\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3.2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eLEFS scores for pre-TKA and post-TKA\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOutcome measures\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003ePre-TKA\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th w (n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 3rd m\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;77)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 6th m (n\u0026thinsp;=\u0026thinsp;54)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003ePost-TKA \u0026ndash; 12th m (n\u0026thinsp;=\u0026thinsp;28)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ep-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLEFS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24.75\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;6.28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e32.2\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e46.8\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;6.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e58.5\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;5.8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e60.25\u003c/p\u003e\u003cp\u003e\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"7\"\u003e* Significant at p\u0026thinsp;\u0026le;\u0026thinsp;0.05; SD: standard deviation; TKA: total knee arthroplasty; w: week; m: month; LEFS: lower extremity functional scale\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe objective of this study was to evaluate foot posture as an outcome measure before and after TKA in individuals with severe knee OA and to determine the correlation of the FPI score with pain and function following TKA.\u003c/p\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003eClinical measurement of foot posture before and after TKA\u003c/h2\u003e\u003cp\u003eThe significant difference in FPI scores between individuals with knee OA and healthy controls suggests that chronic knee joint degeneration may influence foot posture. Specifically, the higher FPI scores in individuals with OA than in healthy individuals indicate a tendency toward a mild to moderately pronated foot posture, which is in line with previous reports \u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e,\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e and reflects compensatory biomechanical strategies developed over time to reduce pain and to maintain mobility. A pronated foot posture may help in shock absorption and load redistribution, especially in the presence of altered knee joint mechanics and pain-driven gait changes associated with OA \u003csup\u003e\u003cspan additionalcitationids=\"CR27\" citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eInterestingly, despite undergoing TKA, there was no statistically significant change in FPI scores at any postoperative time point up to 12 months, indicating that surgical correction of the knee alone may not be sufficient to influence established foot posture. This finding may reflect the persistence of neuromuscular adaptations and learned movement patterns developed during the chronic phase of OA, which are not automatically reversed with surgical intervention \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e,\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. However, the reduced number of participants at later follow-ups may have limited the ability to detect subtle longitudinal changes.\u003c/p\u003e\u003cp\u003eSeveral factors could explain why foot posture remains altered following TKA. First, while TKA addresses structural and functional issues at the knee joint, it does not directly target the foot or ankle complex. Chronic adaptations in the foot, such as ligamentous laxity or altered muscle activation, may persist unless they are specifically addressed through rehabilitation \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. Furthermore, the duration of preoperative symptoms, which averaged nearly 16 months, may contribute to the entrenchment of compensatory mechanisms that are slow to change, even with improved knee function and reduced pain. Even 12 months after TKA, FPI scores differ significantly between individuals with knee OA and healthy controls, suggesting that foot posture may remain unaffected by surgical correction of the knee joint. This highlights the need to recognize and manage secondary musculoskeletal adaptations, such as altered foot posture, that may persist despite successful knee realignment \u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e,\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003eCorrelation of FPI scores with pain and function following TKA\u003c/h2\u003e\u003cp\u003eAlthough pain significantly improved after TKA, the weak correlation between FPI scores and pain suggests that pain relief alone does not directly translate to normalization of foot posture. Additionally, no significant correlation was found between FPI and functional performance as measured by the LEFS score, indicating that improvements in functional ability post-TKA may occur independently of changes in foot posture. This may be attributed to the fact that functional recovery is influenced by multiple factors, including muscle strength, joint stability, proprioception, and patient engagement in rehabilitation, rather than static foot alignment alone. These findings highlight the importance of addressing foot posture and gait mechanics through comprehensive rehabilitation programs that go beyond knee joint recovery, particularly in patients exhibiting persistent postural deviations despite surgical intervention \u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e,\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e,\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThese findings suggest that knee OA is associated with a more pronated foot posture, which does not significantly change following TKA, even with substantial pain reduction. This could be due to long-standing neuromuscular and biomechanical adaptations that persist unless specifically targeted. Strategies can be developed to improve foot posture, restore lower limb biomechanics, and enhance long-term function.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003eClinical implications\u003c/h2\u003e\u003cp\u003eThis study offers important clinical insights into the persistence of altered foot posture following TKA in individuals with knee OA. The findings highlight the value of using accessible and clinically feasible tools such as the FPI to monitor lower limb alignment beyond the knee joint. Although TKA effectively improves joint structure, relieves pain, and enhances function, our results suggest that associated compensatory changes in foot posture particularly a tendency toward pronation may not resolve postoperatively without specific intervention.\u003c/p\u003e\u003cp\u003eThese persistent postural alterations may contribute to inefficient gait mechanics or uneven load distribution, even after successful surgical correction. This underscores the importance of a holistic, kinetic-chain-based approach in post-TKA rehabilitation, one that considers the interdependent nature of the lower extremity kinetic chain. Clinical evaluation should be routinely extended to the foot and ankle, not only for diagnostic purposes but also to inform targeted rehabilitation planning. Rehabilitation programs following TKA should incorporate strategies aimed at improving foot and ankle function, including strengthening exercises, neuromuscular control training, and gait retraining. In cases of persistent foot misalignment, the use of orthotics or supportive footwear may also be beneficial. Such comprehensive interventions can promote better biomechanical efficiency and potentially reduce the risk of secondary complications or future joint strain.\u003c/p\u003e\u003cp\u003eMoreover, the lack of a strong correlation between foot posture and improvements in pain or function highlights that traditional outcome measures may not fully capture the scope of biomechanical adaptation. Therefore, integrating FPI assessment with routine follow-up could serve as an additional metric for identifying individuals who may benefit from extended or specialized rehabilitation. Overall, these findings support a more integrated and personalized approach to post-TKA care, one that addresses not only pain and mobility at the knee, but also the functional alignment of the entire lower limb to optimize long-term outcomes and patient quality of life.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003eLimitations\u003c/h2\u003e\u003cp\u003eThe reduction in sample size at the 6th (n\u0026thinsp;=\u0026thinsp;54) and 12th (n\u0026thinsp;=\u0026thinsp;28) months post-TKA follow-up, due to participant attrition, may have limited the statistical power of the study and restricted the generalizability of the findings, particularly regarding the longitudinal interpretation of FPI, pain, and function trends. Although the FPI is a reliable and clinically feasible tool, it is semiquantitative and subject to interrater variability, which could have introduced measurement bias. Additionally, the study did not account for potential confounding factors such as differences in rehabilitation protocols, footwear habits, or physical activity levels, all of which may influence foot posture independent of surgical correction.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003eFuture recommendations\u003c/h2\u003e\u003cp\u003eFuture studies may explore the relationship between foot posture and lower limb alignment parameters such as the hip-knee-ankle (HKA) angle or tibial torsion to provide a more comprehensive understanding of compensatory biomechanical adaptations post-TKA. Additionally, long-term follow-up beyond 12 months could offer valuable insights into whether persistent changes in foot posture stabilize, worsen, or improve over time. Future rehabilitation protocols following TKA should consider routine foot posture assessments and address compensatory postural changes. Further research incorporating objective measures such as 3D gait analysis, plantar pressure distribution, or dynamic balance testing may help correlate foot posture alterations with functional gait outcomes. Studies evaluating the effectiveness of specific post-TKA rehabilitation strategies, including foot orthoses, gait retraining, and ankle-foot strengthening, could also help inform evidence-based clinical guidelines for enhancing recovery, optimizing lower limb biomechanics and improving long-term functional outcomes.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe present study highlights the role of foot posture as an important outcome measure of biomechanical adaptation in individuals with severe knee OA before and after TKA. Significant differences in FPI scores were observed between individuals with knee OA and healthy controls. However, no significant change was observed in the FPI scores in individuals with knee OA before and after TKA indicating persistent foot posture deviations. A weak linear correlation was observed between the FPI score and pain following TKA, whereas no significant correlation was found with functional performance. Understanding foot posture changes and their relationships with clinical and functional variables is essential in post-TKA rehabilitation planning. Incorporating foot posture assessment into routine clinical practice may enhance the overall recovery process and contribute to long-term functional outcomes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eOA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eOsteoarthritis\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eTKA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTotal Knee Arthroplasty\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eFPI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eFoot Posture Index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIEC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eInstitutional Ethics Committee\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCTRI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eClinical Trial Registry \u0026ndash; India\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eSTROBE\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eStrengthening the Reporting of Observational studies in Epidemiology\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ecm\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eCentimetre\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ekg\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eKilogram\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003ekg/m2\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eKilogram per meter square\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eBody Mass Index\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eNPRS\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eNumerical Pain Rating Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eLEFS\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eLower Extremity Functional Scale\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Institutional Ethics Committee (IEC) of the tertiary care hospital provided ethical approval (IEC1 - 20 - 2022). This study was conducted in accordance with the Code of Ethics of the World Medical Association (Declaration of Helsinki). The study protocol was registered with the Clinical Trial Registry-India (CTRI/2022/07/043642).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from all participants for the publication of any identifying images or clinical data included in this manuscript. All participants were informed that their information and images may be published in a scientific journal and that their identities would be protected to the fullest extent possible.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSS conceptualized and designed the study, prepared initial protocol, performed IEC registration and CTRI registration, conducted the methodology, data collection and data analysis and writing of the manuscript. MRKG performed theformal analysis, review \u0026amp; editing of the manuscript, and overall supervision. SV performed the formal analysis, review \u0026amp; editing of the manuscript, and overall supervision. GAM performed the formal analysis, review \u0026amp; editing of the manuscript, and overall supervision. BMG performed the formal analysis, review \u0026amp; editing of the manuscript, and overall supervision. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to acknowledge the participants for their time and voluntary participation in this study. The authors would like to thank the Manipal Academy of Higher Education (MAHE) for providing all the support and resources for the conduct of this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eKrasnokutsky, S., Attur, M., Palmer, G., Samuels, J. \u0026amp; Abramson, S. B. Current concepts in the pathogenesis of osteoarthritis. \u003cem\u003eOsteoarthritis Cartilage\u003c/em\u003e \u003cstrong\u003e16\u003c/strong\u003e, S1\u0026ndash;S3 (2008).\u003c/li\u003e\n\u003cli\u003eVitaloni, M. \u003cem\u003eet al.\u003c/em\u003e Global management of patients with knee osteoarthritis begins with quality of life assessment: a systematic review. \u003cem\u003eBMC Musculoskelet Disord\u003c/em\u003e \u003cstrong\u003e20\u003c/strong\u003e, 493 (2019).\u003c/li\u003e\n\u003cli\u003eNelson, A. E. 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J. \u003cem\u003eet al.\u003c/em\u003e Rehabilitation for Total Knee Arthroplasty. \u003cem\u003eAm J Phys Med Rehabil\u003c/em\u003e \u003cstrong\u003e102\u003c/strong\u003e, 19\u0026ndash;33 (2023).\u003c/li\u003e\n\u003cli\u003eCapin, J. J., Bade, M. J., Jennings, J. M., Snyder-Mackler, L. \u0026amp; Stevens-Lapsley, J. E. Total Knee Arthroplasty Assessments Should Include Strength and Performance-Based Functional Tests to Complement Range-of-Motion and Patient-Reported Outcome Measures. \u003cem\u003ePhys Ther\u003c/em\u003e \u003cstrong\u003e102\u003c/strong\u003e, (2022).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"foot posture, total knee arthroplasty, total knee replacement, knee osteoarthritis","lastPublishedDoi":"10.21203/rs.3.rs-7307384/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7307384/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTotal knee arthroplasty (TKA) is commonly performed to relieve pain and improve knee function in individuals with severe knee osteoarthritis (OA). Abnormal foot mechanics can influence overall biomechanics and affect post-surgical outcomes. This study aimed to evaluate foot posture as a biomechanical outcome before and after TKA and to explore its relationship with pain and lower extremity function. Seventy-seven individuals with knee OA who underwent TKA, and 77 healthy controls were assessed. Foot posture was measured using the Foot Posture Index (FPI), pain using the Numerical Pain Rating Scale (NPRS), and function using the Lower Extremity Functional Scale (LEFS). Assessments were conducted preoperatively and at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Preoperative FPI scores were significantly higher in the OA group than in controls (1.52\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 vs. 0.70\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2; p\u0026thinsp;=\u0026thinsp;0.03), indicating a more pronated foot posture. FPI scores did not significantly change throughout the follow-up period. At 6 months post-TKA, FPI remained higher than controls (p\u0026thinsp;=\u0026thinsp;0.03), but the difference was not significant at 12 months (p\u0026thinsp;=\u0026thinsp;0.12). A weak positive correlation was found between FPI and NPRS (r\u0026thinsp;=\u0026thinsp;0.2; p\u0026thinsp;\u0026lt;\u0026thinsp;0.05), but no correlation was observed with LEFS. Foot posture evaluation may support comprehensive rehabilitation planning after TKA.\u003c/p\u003e","manuscriptTitle":"Foot Posture as a Biomechanical Outcome Measure Following Total Knee Arthroplasty in Individuals with Severe Knee Osteoarthritis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-25 15:05:04","doi":"10.21203/rs.3.rs-7307384/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-11-06T06:48:00+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-29T05:31:15+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-14T06:12:32+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-11T14:09:50+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"105477869216511507945437344467026384068","date":"2025-10-09T14:00:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"181493815208430182390001379204555312948","date":"2025-10-08T22:23:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"35671090266851469367467086870825847581","date":"2025-10-08T13:10:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-06T20:35:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"33415503897147498834053102540285478541","date":"2025-09-05T15:10:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"317853774416398244285486463811532068876","date":"2025-09-03T13:33:14+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-17T01:13:58+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-08-17T01:03:25+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-08-11T09:22:08+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-08T11:53:52+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-08-08T11:50:42+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"82b8cbca-911b-45c7-a2bc-21d9436937d8","owner":[],"postedDate":"August 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":53393152,"name":"Health sciences/Diseases"},{"id":53393153,"name":"Health sciences/Health care"},{"id":53393154,"name":"Health sciences/Medical research"},{"id":53393155,"name":"Health sciences/Rheumatology"}],"tags":[],"updatedAt":"2025-12-08T16:02:25+00:00","versionOfRecord":{"articleIdentity":"rs-7307384","link":"https://doi.org/10.1038/s41598-025-31351-0","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-12-05 15:57:54","publishedOnDateReadable":"December 5th, 2025"},"versionCreatedAt":"2025-08-25 15:05:04","video":"","vorDoi":"10.1038/s41598-025-31351-0","vorDoiUrl":"https://doi.org/10.1038/s41598-025-31351-0","workflowStages":[]},"version":"v1","identity":"rs-7307384","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7307384","identity":"rs-7307384","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}