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Article

Alterations in Static Plantar Pressure Before and After Total Knee Arthroplasty in Individuals with Knee Osteoarthritis

by
Saidan Shetty
1,
G Arun Maiya
2,
Mohandas Rao KG
3,
Sandeep Vijayan
4,
Shetty Shrija Jaya
2 and
Bincy M George
3,*
1
Department of Anatomy, Melaka Manipal Medical College—Manipal Campus, Manipal Academy of Higher Education (MAHE), Manipal 576104, India
2
Department of Physiotherapy, Centre for Podiatry & Diabetic Foot Care and Research, Manipal College of Health Professions (MCHP), Manipal Academy of Higher Education (MAHE), Manipal 576104, India
3
Division of Anatomy, Department of Basic Medical Sciences, Manipal Academy of Higher Education (MAHE), Manipal 576104, India
4
Department of Orthopaedics, Kasturba Medical College (KMC) Manipal, Manipal Academy of Higher Education (MAHE), Manipal 576104, India
*
Author to whom correspondence should be addressed.
Prosthesis 2025, 7(5), 128; https://doi.org/10.3390/prosthesis7050128
Submission received: 18 August 2025 / Revised: 22 September 2025 / Accepted: 25 September 2025 / Published: 15 October 2025
(This article belongs to the Section Orthopedics and Rehabilitation)
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Abstract

Background/Objectives: Knee osteoarthritis (OA) alters lower limb biomechanics, often leading to an asymmetric plantar pressure distribution. Total knee arthroplasty (TKA) aims to restore joint function and may normalize plantar loading, but evidence from instrumented static pressure analysis is limited. The objective of this study was to compare static plantar pressure distributions before and after TKA in individuals with knee OA and in age- and sex-matched healthy controls. Methods: A pre-post study was conducted on 77 individuals with severe knee OA (Kellgren–Lawrence grade 4) who underwent TKA and 77 matched healthy controls. The plantar pressure area, average pressure, and maximal pressure were assessed preoperatively and at 6 and 12 months postoperatively using a Win-Track force platform. Standard postoperative rehabilitation was followed. Statistical analyses included independent t-tests and repeated-measures ANOVA (p ≤ 0.05). Results: Compared with controls, pre-TKA patients presented significantly lower plantar pressure area, average pressure, and maximal pressure than controls (p < 0.001). At 6 and 12 months post-TKA, the plantar pressure area (p < 0.001) and average pressure (p = 0.001) improved significantly, with more balanced bilateral loading and increased forefoot weight transfer. At 12 months, no significant differences in any plantar pressure parameters remained between the TKA and control groups. Conclusions: Severe knee OA is associated with altered static plantar pressure patterns, characterized by reduced loading and asymmetry. TKA effectively restores plantar pressure distribution, achieving normalization within 12 months. The incorporation of plantar pressure assessment into pre- and postoperative care may guide targeted rehabilitation and enhance functional recovery.

1. Introduction

Knee osteoarthritis (OA) is a degenerative joint disorder characterized by cartilage degradation, joint space narrowing, and chronic pain, which often results in significant functional limitations [1,2]. Individuals with knee OA frequently adopt compensatory gait patterns to minimize discomfort, which can lead to altered biomechanics throughout the lower limb [3,4,5]. A major consequence is the development of maladaptive plantar pressure features, including asymmetrical weight-bearing, excessive loading on the contralateral limb, increased forefoot or heel pressures, and medial–lateral imbalances. These alterations can contribute to secondary musculoskeletal issues, such as hip or low back pain due to abnormal load transfer, ankle and foot disorders resulting from uneven pressure distribution, and overuse injuries in the contralateral limb, ultimately compromising overall lower limb functioning [6,7,8,9].
Total knee arthroplasty (TKA) is a well-established surgical procedure aimed at alleviating pain and restoring joint function in individuals with end-stage knee OA [10,11]. Although surgery primarily targets the knee joint, its effects are biomechanically far-reaching. By correcting varus or valgus deformities, restoring the mechanical axis, normalizing tibiofemoral and patellofemoral tracking, and improving range of motion, TKA has the potential to improve static plantar pressure distribution by reducing pathological forefoot or heel loading and restoring a more symmetrical weight-bearing pattern at rest. However, these benefits are not always uniform, as preoperative compensation, such as altered gait mechanics; reliance on the contralateral limb or trunk lean; residual muscle imbalances, such as persistent quadriceps weakness, hamstring tightness, or hip abductor deficits; and variations in rehabilitation protocols, including differences in exercise intensity, frequency, and progression, may influence postoperative outcomes [12,13,14].
To objectively assess changes in plantar loading, plantar pressure measurement tools are crucial. The Win-Track force platform is a reliable and validated system that enables detailed evaluation of static plantar pressure distribution. It demonstrates good metrological performance in terms of measurement uncertainty, repeatability, stability over time, and minimal hysteresis, ensuring consistent and accurate assessment of plantar loading patterns. Its high-resolution sensors capture subtle differences in loading patterns across different regions of the foot, providing a comprehensive picture of standing plantar pressure distribution before and after TKA. Such precise measurements are valuable in identifying functional recovery, as well as persistent abnormalities that may require clinical attention, such as medial or lateral forefoot overloading, asymmetrical weight-bearing between limbs, or excessive heel pressure, which may predispose patients to altered gait mechanics, foot disorders, or delayed rehabilitation outcomes [15,16,17].
Previous studies have explored static plantar loading patterns in individuals with knee OA. Studies consistently report altered weight-bearing, characterized by increased load on the contralateral limb, forefoot or hindfoot overloading, and asymmetrical medial–lateral pressure distribution. These compensatory patterns often persist until surgical intervention, reflecting the biomechanical adaptations patients develop to minimize pain and maintain mobility. Understanding these OA-specific alterations is crucial, as they may contribute to secondary joint problems, impaired postural control, and increased risk of falls if not corrected through intervention and rehabilitation [7,18,19,20].
Despite the known interdependence between knee mechanics and foot loading, limited research has focused on evaluating plantar pressure patterns following TKA using instrumented platforms. While earlier studies have examined dynamic gait parameters or short-term postoperative outcomes, little is known about static plantar pressure distribution and its comparison with healthy controls. A clearer understanding of these parameters is essential, especially as persistent abnormal plantar pressures can contribute to gait inefficiencies or predispose individuals to further musculoskeletal issues post-surgery, such as contralateral knee overload, hip or low back pain from compensatory movements, and foot pathologies including plantar fasciitis or metatarsalgia.
Therefore, this study aimed to compare the static plantar pressure distribution before and after TKA in individuals with knee OA using the Win-Track force platform and to compare these findings with those of age- and sex-matched healthy controls. By directly addressing maladaptive plantar pressure features characteristic of severe knee OA and examining the extent to which TKA can reduce or normalize them, this study provides novel insights into biomechanical adaptations following surgical intervention and underscores their clinical relevance for guiding targeted rehabilitation strategies and improving functional recovery.

2. Materials and Methods

2.1. Study Design and Participants

This is a pre-post study design conducted at the Department of Physiotherapy and Department of Orthopedics, Kasturba Hospital, Manipal, Karnataka, India. Ethical approval was obtained from 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. Informed consent was obtained from all participants included in the study. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines were followed [21].
The inclusion criteria of the knee OA group were patients aged 50–80 years of either sex with primary severe knee OA (Kellgren–Lawrence grade 4) who were scheduled for TKA. The inclusion criteria for the control group were healthy individuals whose age-, sex-, and BMI distributions were similar and who did not have any current lower extremity orthopedic injuries or neurological, immunological, inflammatory, or cardiovascular diseases. The exclusion criteria were as follows: individuals who had a history of neurological impairments affecting lower limb function or immunological or inflammatory conditions; those with a history of major medical, cardiac, or vascular events within the past year; and those who were not willing to participate in the study.

2.2. 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. The outcome measures were recorded preoperatively and postoperatively at 6 and 12 months. Seventy-seven age- and sex- matched control participants with similar distributions of age, sex, and BMI who met the inclusion criteria were recruited to compare the data with those of the TKA group.

2.3. Intervention Program

The participants in the TKA group followed the postoperative rehabilitation programme at Kasturba Hospital, Manipal. Following the surgery, all the participants underwent a standard postoperative TKA rehabilitation program. The inpatient and outpatient rehabilitation protocols were followed. The rehabilitation protocol included general exercises; pain and swelling management; mobility exercises; range of motion (ROM) exercises; muscle activation and strengthening exercises; stretching; ambulation; closed chain and balance exercises; cardiovascular exercises; and functional training.
Stage 1 exercises were implemented during the early function phase, spanning from day 1 to 2 weeks post-TKA. Along with the standard rehabilitation program, specific exercises targeting vastus medialis oblique (VMO) muscle activation, such as isometrics of the quadriceps, terminal knee extension short arc, straight leg raise, knee extension while sitting (90°-0), and the McConnell method of VMO contraction in high sitting, were included and were performed thrice a day. Stage 2 exercises were introduced during the progressive function phase, covering weeks 3 to 6 post-TKA. Strengthening exercises with cuff weights ranging from 0.5 to 1 kg, which included terminal knee extension short-arc, straight leg raising, knee extension while sitting (90°-0), and VMO contraction while high sitting using the McConnell method, were performed twice a day, with 3 sets of 20 repetitions each. The closed-chain activity of VMO contraction while standing was performed twice a day. Stage 3 exercises were administered in the advanced function phase, from weeks 7–12 following TKA. The strengthening exercises progressed with cuffed weights of 2 kg or 60% of 1 RM performed twice a day, with 3 sets of 30 repetitions. The progressive stages included other general exercises, mobility-based and stretching exercises, functional training, balance training, and aerobic conditioning [22,23].

2.4. Plantar Pressure Analysis

For the plantar pressure analysis, the participant’s weight was measured using a digital weighing scale (HealthSense, India, Model No.: PS 130) (Figure 1), height was measured using a stadiometer (Prestige, India, Model No.: SMPW 210) (Figure 2), and foot size was measured using a foot size measuring scale (Callaron China, Model No.: 45F03CD19X) (Figure 3). The plantar pressure analysis was performed using a Win-Track (Medicapteurs Technology, Balma, France) force platform (Figure 4). The test was performed by the same physical therapist; thus, the participants received the same instructions prior to the test.
The static plantar pressure analysis included measurements of the plantar pressure area, average plantar pressure, and maximal plantar pressure. During the test, the participants were instructed to stand barefoot on the platform with their feet shoulder-width apart (approximately 15 cm), their arms resting naturally by their sides, and their eyes fixed at a designated point on the wall at eye level. They were asked to remain as still and relaxed as possible in an upright posture. The data were recorded continuously for 30 s (Figure 5). A 30 s duration was chosen because it provides representative data with minimal fatigue or sway, and the Win-Track platform remains stable without significant signal drift. With intraclass correlation coefficients (ICCs) ranging from 0.75 to 0.88, indicating good to excellent reliability, the Win-Track platform provides consistent and reproducible measurements of plantar pressure [17].

2.5. Statistical Analysis

The data were analyzed via Jamovi 2.6.23. The distribution of the dataset was evaluated for normality using the Kolmogorov–Smirnov test to guide the selection of suitable statistical analyses. The data were found to be normally distributed. Continuous variables are represented as the means, standard deviations, frequencies and percentages. Independent sample t-tests were used to compare the data between preoperative individuals and age- and sex-matched controls. Repeated measures ANOVA was used to compare the quantitative measures of the preoperative data and the postoperative data at 6 and 12 months. Effect sizes were reported alongside the main analyses (Cohen’s d for independent t-tests and partial eta squared [η2p] for repeated measures ANOVA) to quantify the magnitude of observed differences. The level of statistical significance was defined as p ≤ 0.05.

3. Results

3.1. Participant Details and Demographic Information

A total of n = 134 individuals were assessed for eligibility, after which n = 77 individuals were recruited based on the predefined sample size. The participants were recruited post-TKA at 6 (n = 54) and 12 months (n = 26).
The demographic and anthropometric characteristics of the TKA group and control group participants were noted (Table 1). The occupations of the individuals were homemakers (n = 28, 36.4%), skilled agricultural, forestry and fishery workers (n = 19, 24.8%), elementary occupations (n = 10, 12.9%), support workers (n = 9, 11.7%), service and sales workers (n = 5, 6.5%), managers and professionals (n = 3, 3.9%), and shopkeepers (n = 3, 3.9%). The comorbidities reported were diabetes (n = 29, 37.7%), hypertension (n = 12, 15.6%), obesity (n = 8, 10.4%), pulmonary diseases (n = 7, 9.1%), cardiovascular history (n = 6, 7.8%), and thyroid disorders (n = 6, 7.8%).

3.2. Comparison of Plantar Pressure Between the Knee OA and Control Groups

There was a statistically significant decrease (p < 0.001) in the plantar pressure area, average plantar pressure, and maximal plantar pressure in the pre-TKA group compared with those in the control group (Table 2). The magnitude of these differences was large, with Cohen’s d indicating very large effects for the plantar pressure area (d = 1.24) and average pressure (d = 1.19) and a moderate-to-large effect for the maximal pressure (d = 0.72). These findings suggest that individuals with knee OA exhibit substantially reduced plantar loading compared with healthy controls.

3.3. Comparison of Plantar Pressure Between the Pre-TKA and Post-TKA Groups

A comparison of pre-TKA data with post-TKA data revealed significant improvements in the plantar pressure area (p < 0.001, η2p = 0.76—large effect) and average plantar pressure (p = 0.001, η2p = 0.22—large effect) (Table 3 and Table 4). Although the maximal plantar pressure showed an increasing trend, it did not reach statistical significance (p = 0.08, η2p = 0.09—small effect).
These findings indicate that total knee arthroplasty is associated with meaningful improvements in plantar loading patterns. Individuals with knee OA tend to shift more weight onto the less affected limb, particularly in the hindfoot region (>200 kPa/point) (Figure 6). Post-TKA, plantar pressure loading demonstrated a more balanced per-point distribution between both feet and across regions of the operated foot, with improved weight transfer over the forefoot.
Figure 6 depicts the plantar pressure distribution during static analysis in the pre-TKA phase, highlighting a distinct asymmetry in weight-bearing. Most of the pressure is concentrated on the left foot, whereas the right foot shows minimal contact, suggesting compensatory offloading, likely due to pain, functional instability, or reduced knee function. A color gradient is used to represent varying pressure levels—blue to green indicates low to moderate pressure, and yellow to red signifies high-pressure zones, which are typically observed under the heel and forefoot. This visualization effectively illustrates abnormal loading patterns and provides valuable insight into the patients’ compromised functional status before they undergo surgical intervention.

3.4. Comparison of Plantar Pressure Between the Post-TKA Group and the Control Group

When the post-TKA data at 6 and 12 months were compared with those of the control group, there were no significant differences in the plantar pressure area (6th month p = 0.29, 12th month p = 0.8) or maximal pressure (6th month p = 0.1, 12th month p = 0.69). However, the average pressure was significant at 6 months post-TKA (p < 0.001), but no significant differences (p = 0.48) were observed at 12 months post-TKA, indicating that the average plantar pressure had reached the normal range 12 months after TKA.
Figure 7 shows the plantar pressure distribution of healthy controls during static analysis. In contrast to the pre-TKA condition, the image demonstrated a more symmetrical weight-bearing pattern between the left and right feet. The pressures are evenly distributed across the hindfoot and forefoot regions, reflecting balanced load sharing and normal postural alignment. The color gradient indicates physiological loading, with yellow to red zones appearing in expected regions such as the heel and metatarsal heads, whereas blue to green zones represent areas of lower pressure. This pattern highlights efficient and symmetrical plantar load distribution, which is characteristic of healthy lower limb function without compensatory offloading.

4. Discussion

The purpose of this study was to compare the static plantar pressure distribution before and after TKA in individuals with knee OA using the Win-Track force platform and to compare these findings with those of age- and sex-matched healthy controls.

4.1. Plantar Pressure Analysis of the Knee OA and Control Groups

The findings of the present study highlight the significant differences in plantar pressure between pre-TKA patients and healthy controls, as well as improvements in plantar pressure distribution after TKA. Specifically, compared with the control group, pre-TKA individuals presented altered plantar pressure patterns, with significant reductions in the plantar pressure area (Cohen’s d = 1.24—very large effect), average pressure (Cohen’s d = 1.19—very large effect), and maximal pressure (Cohen’s d = 0.72—moderate-to-large effect). These differences may reflect the altered load distribution commonly observed in individuals with knee OA. The imbalance in pressure distribution, particularly the increased load on the less affected hindfoot, could be indicative of an effort by the patient to minimize pain or discomfort in the affected knee joint.
This finding aligns with previous studies that have documented altered loading patterns in individuals with knee OA, which often results in greater pressure on the less affected leg and specific regions of the foot to reduce the strain on the compromised joint [18,24]. For example, Kamenaga et al. [24] reported that individuals with unilateral knee OA displayed increased plantar pressures on the contralateral limb and the hindfoot region to reduce joint loading and avoid pain in the affected knee. Similarly, Filho et al. [18] reported increased pressure in the lateral forefoot and heel [18].

4.2. Plantar Pressure Analysis in the Pre-TKA and Post-TKA Groups

The post-TKA results suggest significant improvements in the plantar pressure area (η2p = 0.76—large effect) and average pressure distribution (η2p = 0.22—large effect), indicating a meaningful shift in pressure patterns. Redistribution of the plantar pressure area and average plantar pressure is essential after TKA because it reduces the load distribution on the knee, thereby facilitating postoperative recovery [19,25]. The significant reduction in localized pressure, particularly over the hindfoot, points to an improvement in overall weight transfer to the forefoot, likely due to the increased function and restored load bearing capacity of the knee joint following the procedure. This finding is consistent with the findings of Ntourantonis et al., [25] who reported that TKA leads to significant normalization of plantar pressure, particularly through reduced hindfoot load and better pressure transfer toward the forefoot during walking [25].
Li et al. [20] reported that pressure-time integrals in the forefoot increased following TKA, indicating improved push-off mechanics and a reduction in compensatory gait strategies. This increase in foot-ground interactions suggests that TKA plays a key role in restoring more physiologically normal gait patterns. As a result, the procedure may help prevent secondary musculoskeletal complications, such as overloading of specific foot regions or the development of other lower limb problems, which are commonly associated with prolonged abnormal gait [20,24]. These improvements support the overall goal of restoring functional mobility and promoting a more complete postoperative recovery.

4.3. Plantar Pressure Analysis of the Post-TKA and Control Groups

Despite these improvements, when 12-month post-TKA data were compared with those of the control group, no significant differences were observed in terms of plantar pressure area, maximal pressure, or average pressure. These findings suggest that the redistribution of plantar pressure, which is often altered due to pain, joint misalignment, and compensatory gait patterns in individuals with knee OA, has normalized by one year after surgery. The restoration of plantar pressure parameters to values comparable with those of healthy controls indicates a return to more symmetrical and physiologically efficient gait mechanics. This recovery reflects improved weight-bearing ability and lower limb alignment post-TKA, likely facilitated by reductions in joint pain, increased quadriceps strength, and enhanced joint stability [19,24]. The observed normalization may also be partially attributed to improvements in proprioceptive feedback and neuromuscular coordination, both of which are critical for balanced load distribution and gait following TKA. While these group-level improvements are promising, monitoring individual variations and ensuring that any residual abnormalities are addressed through targeted physiotherapy interventions to optimize long-term outcomes remain essential.

4.4. Clinical Implications of the Study

This long-term study aimed to investigate the changes in plantar pressure in individuals with knee OA following TKA. The study also highlights the applicability of the Win-Track force platform for assessing plantar pressure in this population. The Win-Track force platform is a user-friendly tool that can be valuable for foot pressure mapping, making it a helpful aid for advanced clinical evaluation and physical rehabilitation both before and after TKA. In individuals with severe knee OA undergoing TKA, monitoring any subsequent changes in plantar pressure after surgery is crucial. Additionally, addressing plantar pressure distribution before and after TKA may contribute to improved patient outcomes and faster, more complete recovery.
Rehabilitation protocols may benefit from incorporating adjunctive strategies such as plantar pressure biofeedback, gait retraining, and dynamic balance exercises, as these approaches have the potential to support normalization of load distribution and reduce long-term complications. Clinicians should also monitor for persistent asymmetries that may not self-correct, especially in older adults or those with limited mobility preoperatively.

4.5. Limitations and Future Recommendations

The loss of participants during long-term follow-up may have affected the strength of the statistical analysis and limited the reliability of the 12-month post-TKA data. This reduction in sample size over time could have influenced the accuracy of the observed trends. One contributing factor is that many patients feel significantly better at the 6-month mark and perceive themselves as nearly normal, leading them to skip the 12-month follow-up. As a result, the number of follow-ups at 12 months was notably lower. Furthermore, variations in individual patient characteristics, such as age, physical condition, or the presence of other medical issues, may have introduced outcome variability that was difficult to control or account for within the study.
Future studies should consider larger, adequately powered samples with stratified analyses based on age, BMI, or OA severity to improve the generalizability and precision of findings. Future research should explore the long-term effects of rehabilitation on plantar pressure following TKA and investigate the impact of additional balance training strategies to further optimize overall function. Future studies should adopt a multi-time-point longitudinal design to better capture the trajectory of recovery, monitor changes over time, and identify critical periods where interventions may have the greatest impact. Furthermore, there is a need for greater insight into how individual patient factors such as age, sex, presurgical joint function, and comorbidity profiles influence recovery trajectories and the sustainability of surgical outcomes. Longitudinal assessments remain essential for fully understanding and evaluating the progression of plantar pressure distribution after surgical interventions.

5. Conclusions

This study demonstrated that, compared with healthy controls, individuals with knee osteoarthritis exhibit significantly altered plantar pressure patterns, characterized by a reduced plantar pressure area and an asymmetric load distribution, particularly favoring the less affected hindfoot. TKA effectively restores plantar pressure parameters by improving weight distribution and facilitating more balanced pressure transfer through the foot. Twelve months after surgery, the plantar pressure measurements in post-TKA individuals were comparable to those in healthy controls, indicating substantial normalization of gait and foot–ground interactions. These findings underscore the importance of TKA not only in alleviating knee joint symptoms but also in restoring lower limb biomechanics. The incorporation of plantar pressure assessment into routine pre- and postoperative evaluations may help guide individualized rehabilitation strategies and enhance functional recovery.

Author Contributions

Conceptualization, S.S.; methodology, S.S.; software, S.S.; validation, M.R.K., S.V., G.A.M., and B.M.G.; formal analysis, S.S.; investigation, S.S., G.A.M., and S.S.J.; resources, S.S.; data curation, S.S.; writing—original draft preparation, S.S.; writing—review and editing, M.R.K., S.V., G.A.M., and B.M.G.; visualization, S.S., M.R.K., S.V., G.A.M., and B.M.G.; supervision, M.R.K., S.V., G.A.M., and B.M.G.; project administration, S.S. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding. The APC was funded by Manipal Academy of Higher Education.

Institutional Review Board Statement

The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Ethics Committee of Kasturba Hospital, Manipal (IEC-20-2022 and 6 June 2022).

Informed Consent Statement

Written informed consent was obtained from all the participants included in the study. Written informed consent has been obtained from the patient(s) to publish this paper.

Data Availability Statement

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

The authors would like to acknowledge the participants for their time and voluntary participation in this study. The authors would like to thank the Centre for Podiatry & Diabetic Foot Care and Research, Manipal College of Health Professions (MCHP), Manipal Academy of Higher Education (MAHE) for providing all the support and resources for the conduct of this study.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
OAOsteoarthritis
TKATotal Knee Arthroplasty
FPIFoot Posture Index
IECInstitutional Ethics Committee
CTRIClinical Trial Registry—India
STROBEStrengthening the Reporting of Observational studies in Epidemiology
cmCentimeter
kgKilogram
kg/m2Kilogram per meter square
BMIBody Mass Index
cm2centimeter square
kPakilo Pascal

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Figure 1. Weighing scale.
Figure 1. Weighing scale.
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Figure 2. Stadiometer.
Figure 2. Stadiometer.
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Figure 3. Foot size measurement scale.
Figure 3. Foot size measurement scale.
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Figure 4. Win-Track force platform (Medicapteurs Technology France).
Figure 4. Win-Track force platform (Medicapteurs Technology France).
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Figure 5. Participant position for plantar pressure assessment on the Win-Track force platform.
Figure 5. Participant position for plantar pressure assessment on the Win-Track force platform.
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Figure 6. Representative image of the plantar pressure assessment using the Win-Track force platform (pre-TKA).
Figure 6. Representative image of the plantar pressure assessment using the Win-Track force platform (pre-TKA).
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Figure 7. Representative image of the plantar pressure assessment in healthy control individuals on the Win-Track force platform. The ⊕ symbol represents the center of pressure (CoP), which represents the body’s overall balance point on the support base.
Figure 7. Representative image of the plantar pressure assessment in healthy control individuals on the Win-Track force platform. The ⊕ symbol represents the center of pressure (CoP), which represents the body’s overall balance point on the support base.
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Table 1. Demographic and anthropometric data of participants in the TKA and control groups.
Table 1. Demographic and anthropometric data of participants in the TKA and control groups.
VariablesTKA Group (n = 77)Control Group (n = 77)p-Value
Age (in years) (Mean ± SD)66.9 ± 7.164.8 ± 9.6 0.18
Gender (Female, Male)Females (n, %)47 (61%)45 (58.4%)
Males (n, %)30 (38.9%)32 (41.6%)
Height (in cm) (Mean ± SD)155.8 ± 8.5157.4 ± 6.10.21
Weight (in kg) (Mean ± SD)69.2 ± 14.165.8 ± 12.30.18
BMI (in kg/m2) (Mean ± SD)28.4 ± 11.325.8 ± 10.20.09
Leg dominance (Right, Left)Right (n, %)72 (93.5%)69 (89.6%)
Left (n, %)5 (6.5%)8 (10.4%)
SD: standard deviation; TKA: total knee arthroplasty; cm: centimeter; kg: kilogram; BMI: body mass index; kg/m2: kilogram per meter square.
Table 2. Mean (±SD) plantar pressure outcomes in the pre-TKA and control groups.
Table 2. Mean (±SD) plantar pressure outcomes in the pre-TKA and control groups.
VariablesPre-TKA (n = 77)Controls (n = 77)MD95% CI% ChangeEffect Size (Cohen’s d)p-Value
Area (cm2)53.7 ± 20.580.2 ± 22.3−27[−33.8, −20.2]33.1%−1.24<0.001 *
Maximal Pressure (kPa)284.2 ± 59.1323.1 ± 48.4−38.9[−56.11, −21.71]12.1%−0.72<0.001 *
Average Pressure (kPa)109.9 ± 28.3139.2 ± 20.2−29.2[−37, −21.3]20.9%−1.19<0.001 *
* Significant at p ≤ 0.05; SD: standard deviation; TKA: total knee arthroplasty; MD: mean difference: 95% CI: 95% confidence interval of the difference; cm2: centimeter square; kPa: kilo Pascal; η2p: partial eta squared (effect size). Effect sizes (η2p) were calculated for repeated-measures ANOVA to quantify the magnitude of group differences.
Table 3. Mean (±SD) plantar pressure outcomes in pre-TKA and post-TKA assessments.
Table 3. Mean (±SD) plantar pressure outcomes in pre-TKA and post-TKA assessments.
VariablesPre-TKA (n = 77)Post-TKA—6th m (n = 54)Post-TKA—12th m (n = 26)Fη2p (Effect Size)p-Value
Area (cm2)53.7 ± 20.576.4 ± 22.179.56 ± 23.277.10.76<0.001 *
Maximal Pressure (kPa)284.2 ± 59.1308.6 ± 50.8318.7 ± 49.62.50.090.08
Average Pressure (kPa)109.9 ± 28.3125.7 ± 15.9135.78 ± 21.57.20.220.001 *
* Significant at p ≤ 0.05; SD: standard deviation; TKA: total knee arthroplasty; m: month; cm2: centimeter square; F: Fisher’s F-statistic; kPa: kilo Pascal.
Table 4. Percentage change in plantar pressure outcomes between pre-TKA and post-TKA assessments.
Table 4. Percentage change in plantar pressure outcomes between pre-TKA and post-TKA assessments.
Variables% Change at 6th m% Change at 12th mp-Value
Area (cm2)29.7%32.6%<0.001 *
Maximal Pressure (kPa)7.9%10.8%0.08
Average Pressure (kPa)12.5%7.4%0.001 *
* Significant at p ≤ 0.05; TKA: total knee arthroplasty; m: month; cm2: centimeter square; kPa: kilo Pascal.
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MDPI and ACS Style

Shetty, S.; Maiya, G.A.; Rao KG, M.; Vijayan, S.; Jaya, S.S.; George, B.M. Alterations in Static Plantar Pressure Before and After Total Knee Arthroplasty in Individuals with Knee Osteoarthritis. Prosthesis 2025, 7, 128. https://doi.org/10.3390/prosthesis7050128

AMA Style

Shetty S, Maiya GA, Rao KG M, Vijayan S, Jaya SS, George BM. Alterations in Static Plantar Pressure Before and After Total Knee Arthroplasty in Individuals with Knee Osteoarthritis. Prosthesis. 2025; 7(5):128. https://doi.org/10.3390/prosthesis7050128

Chicago/Turabian Style

Shetty, Saidan, G Arun Maiya, Mohandas Rao KG, Sandeep Vijayan, Shetty Shrija Jaya, and Bincy M George. 2025. "Alterations in Static Plantar Pressure Before and After Total Knee Arthroplasty in Individuals with Knee Osteoarthritis" Prosthesis 7, no. 5: 128. https://doi.org/10.3390/prosthesis7050128

APA Style

Shetty, S., Maiya, G. A., Rao KG, M., Vijayan, S., Jaya, S. S., & George, B. M. (2025). Alterations in Static Plantar Pressure Before and After Total Knee Arthroplasty in Individuals with Knee Osteoarthritis. Prosthesis, 7(5), 128. https://doi.org/10.3390/prosthesis7050128

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