|Year : 2022 | Volume
| Issue : 3 | Page : 270-278
The association of foot posture and osteoarthritis of the medial compartment of the knee joint: A literature review
Shrikant Wagh1, Rizwan Razak2
1 Lupus Clinic, Pune, Maharashtra, India
2 Department of Rheumatology, Croydon Healthcare Services NHS Trust, London, UK
|Date of Submission||22-Feb-2022|
|Date of Acceptance||05-Jul-2022|
|Date of Web Publication||18-Aug-2022|
Dr. Shrikant Wagh
Lupus Clinic, 1078, Shukrawar Peth, Hirabag, Tilak Road, Pune - 411 002, Maharashtra
Source of Support: None, Conflict of Interest: None
Osteoarthritis (OA) of the knee joint (KOA) is a major cause of morbidity among older adults. Medial compartment KOA (MCKOA) is the more common form. High body mass index (BMI), obesity, and older age are some of the risk factors for KOA. Adult acquired pronated foot deformity is another common condition with some common risk factors. This systematized review aims to assess the association of MCKOA and posture of the foot and the impact of assessment of foot posture in the management of MCKOA. A search was carried out from PubMed, Cochrane, and Google Scholar for studies related to the association of foot posture and MCKOA. 11 studies (out of 5926) that met the inclusion criteria were selected for analysis. These studies (3685 participants) were divided into two subgroups: (a) studies of association of foot posture with MCKOA (n = 8) and (b) studies of association between foot pain and knee pain/osteoarthritis (n = 3). The studies are heterogeneous due to different methods of foot posture assessment, KOA diagnosis, and noninclusion of covariates such as age, gender, and BMI. These studies indicate that there is an association between pronated foot posture and MCKOA. There is insufficient evidence to determine the impact of foot posture assessment in the management of MCKOA. An assessment of foot posture followed by correction with customized orthoses may help relieve pain in some of these patients. It is, therefore, essential to assess the foot posture in all patients of KOA.
Keywords: Foot assessment, foot posture, knee osteoarthritis, medial compartment, planus foot
|How to cite this article:|
Wagh S, Razak R. The association of foot posture and osteoarthritis of the medial compartment of the knee joint: A literature review. Indian J Rheumatol 2022;17:270-8
| Introduction|| |
Osteoarthritis (OA) of the knee joint is the most common form of peripheral joint arthritis. The estimated global prevalence of knee OA (KOA) is 16% (95% confidence interval [CI], 14.3%–17.8%), and an estimated global incidence is 203/10,000 person-years (95% CI, 106–331). It affects approximately 37% of the population aged 60 years and above, and it is a significant cause of morbidity due to pain, loss of function, and diminished quality of life. High body mass index (BMI), obesity, history of a knee injury, female sex, age (50–75 years), and intense physical activity are the known risk factors involved in the development of OA (KOA). In addition, there is a prospective association between symptomatic OA and increased risk for all-cause death, cardiovascular events, development of diabetes, diabetes complications, and depression.
KOA is diagnosed by the clinical features and radiological examination though the clinical features may not necessarily correlate with the radiological score. The prevalence of medial compartment KOA (MCKOA) is 5–10 times higher than OA of other compartments because 60% of the weight is transmitted through the medial knee during walking.
Adult acquired flat-foot (pes planus or pronated foot) deformity is another common condition affecting 3%–10% population. Studies suggest that it may be related to the posterior tibialis tendon dysfunction. The abnormal posture of the feet and MCKOA involve similar risk factors, such as age, female sex, and high BMI. Furthermore, there is a strong association between obesity and pes planus, foot pronation, and increased plantar pressure during walking. Foot posture can be easily assessed using the foot posture index (FPI) and other clinical methods. Foot orthosis can improve physical function, pain, and required energy during walking in cases of flexible pes planus (good to low-level evidence). Recognizing a particular type of foot posture at an early stage may help prevent the development and progression of MCKOA.
To the best of the author's knowledge, while several studies are published on foot posture in knee pain or KOA, no reviews have investigated the relationship between abnormal foot posture and MCKOA. An appraisal was, therefore, planned to study the association between these two conditions. The aims of this review are as follows:
- To study the association between an abnormal posture of feet and MCKOA, and
- To explore the impact of assessment of foot posture in the management of MCKOA.
| Materials and Methods|| |
The published literature in the English language freely available on the Internet was searched between January 26, 2021, and April 15, 2021. The data were collected by a single reviewer (SW). No automation tools were used during the search process. There was no limitation on study dates. PubMed (3918 titles) and Cochrane (58 titles) databases were searched. Google Scholar (1950 titles) search was also carried out up to the first 50 pages. Key terms used during the search were as follows: “knee osteoarthritis” and “osteoarthritis of the knee joint” AND “foot deformities,” “foot posture,” “feet abnormalities,” “pes planus,” “flat feet,” “foot-posture,” “flat foot,” “posterior subtalar joint,” “midtarsal joint,” and “hallux valgus.” Other Medical Subject Heading keywords were also used as required. Only freely available full-text articles were selected for this review.
Thus, the inclusion criteria were as follows: (1) all full-text articles published in journals indicating the relationship between foot posture or foot pain and MCKOA, (2) Studies published in the English language, and (3) published articles available on Internet using specific key terms. The exclusion criteria were as follows: (1) the articles published in languages other than English, (2) studies that have no mention of medial compartment of the knee joint, (3) kinematic studies related to the correlation between KOA and foot posture, and (4) conference papers and abstracts only.
After going through their title, abstract, and methodology, the preliminary selection of articles was carried out, ensuring that duplication is avoided. This study, being a literature review, was not registered in PROSPERO, the international prospective register of systematic reviews.
Further, on thoroughly analyzing the preliminarily selected studies, those relevant to the objectives of this review were selected for data analysis. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews and meta-analyses was used to guide this review.
The quality of studies was assessed by the Newcastle–Ottawa scale (NOS) under three domains: selection of the study groups, comparability of the studies based on the design or analysis, and ascertainment of outcomes of interest [Table 1]. NOS was applied to cohort and case–control studies, whereas a modified NOS was applied to cross-sectional studies.
|Table 1: Quality assessment of studies using Newcastle-Ottawa Scale for assessing cohort studies|
Click here to view
The selected studies were subdivided into two groups: (a) studies of association of foot posture with MCKOA (n = 8),,,,,,,, and (b) studies of association of foot pain and knee pain/osteoarthritis (OAI studies) (n = 3).,, Data that apply to the objectives of this review was extracted from each selected study. These data were then combined for the final analysis and to draw appropriate conclusions.
| Results|| |
The search and screening process is summarized in the PRISMA study flow diagram [Figure 1]. A total of 5954 records were identified, and 2001 titles with abstracts were screened after removing duplicate studies. 1948 articles were not relevant to the study questions. Thirty-eight full-text articles were excluded as there was no mention of the medial compartment of the knee in these osteoarthritis studies. Four articles with kinematic studies were also excluded. Thus, 11 studies were selected for this review. All of these observational studies were pre-planned.
|Figure 1: The Preferred Reporting Items for Systematic reviews and Meta-Analyses study flow diagram|
Click here to view
Three excellent quality cohort studies were included though they studied the association of foot pain and not posture with knee pain.,, One of these three studies has implied MCKOA in the methods section. The inclusion of these studies was based on the association of planus and pronated foot with foot symptoms, including generalized foot pain, arch pain, and heel pain, as shown in the Framingham Foot Study.
Five studies have not specified the involved KOA compartment in their titles or abstracts, though discussed in the observations or discussion. Three excellent quality studies were carried out on the OA Initiative cohort of 4796 participants.,, Another study of the same cohort has shown that knee pain, which is an essential clinical criterion for KOA classification, over 1 year predicts accelerated cartilage volume loss and increased risk of incident and progressive radiographic OA. One of the parameters tested over four years was worsening minimum medial tibiofemoral joint space width in the latest among these three selected studies. This parameter indicates the study of medial joint space width in all these three studies. One study includes 92 patients of MCKOA (96.8%) out of a total of 95 participants. One study has assessed FPI-6 in 100 patients of KOA with KL grade 2.36 ± 0.78. The sample likely included more MCKOA as this is the most common form of KOA and the entire discussion relates to MCKOA.
All 11 studies are summarized according to the classification mentioned in methods [Table 2] and [Table 3]. These studies have collectively reported an association between foot pain/posture and MCKOA in 3685 patients [Table 4]. There are two cohort studies, two case–control studies, and seven cross-sectional studies. These studies were carried out in Australia (Melbourne), China (Guangzhou), Japan (Hiroshima), India (Loni and Pune), Morocco, Turkey, and the USA (Massachusetts/multicenter). There are seven studies with 9–10 stars (excellent quality), two studies with 7–8 stars (very good quality), and two studies with five stars (fair quality) according to the NOS [Table 1], [Table 5] and [Table 6].
|Table 2: Association of foot posture with medial compartment knee osteoarthritis|
Click here to view
|Table 3: Association of foot pain and knee pain/osteoarthritis (the osteoarthritis initiative studies)|
Click here to view
|Table 4: Association of the flat foot with medial compartment knee osteoarthritis|
Click here to view
|Table 5: Quality assessment of studies using Newcastle-Ottawa Scale for assessing case-control studies|
Click here to view
|Table 6: Quality assessment of studies using a modified Newcastle-Ottawa Scale for assessing cross-sectional studies|
Click here to view
| Discussion|| |
We performed a review of available literature as per inclusion and exclusion criteria to know the association between foot posture and MCKOA and the impact of assessment of foot posture in the management of MCKOA. This review indicates that there is a linear association between planus foot posture and which needs to be evaluated in all patients with MCKOA as an appropriate orthotic correction may relieve knee pain in some of these patients.
The diagnosis of MCKOA was based on knee pain, radiography, and magnetic resonance imaging (MRI) alone or in combination during these studies. Knee pain is an essential, but not the only, criterion for the classification of KOA. Low interobserver reproducibility and lack of intra-observer uniformity are the significant limitations of KL classification. MRI is a better tool than radiography for the assessment of OA progression through features of KOA can be observed on MRI examination in 19%–43% of asymptomatic, uninjured adults over 40 years of age. The MOST study has shown that 25% of KL grade 2 and >70% of KL grade 3 KOA show full-thickness cartilage damage in the medial tibiofemoral compartment on MRI. However, 20% of KL grade 2 and 6% of KL grade 3 KOA do not show any cartilage damage on MRI. While the method of assessment of KOA is crucial in the studies on the progression of KOA, it may not be necessary for establishing the association between KOA and foot posture.
The assessment of foot posture was carried out by various techniques that have advantages and disadvantages based on the equipment required, the degree of necessary clinical expertise, availability of normative values, reliability, validity, and relationship with dynamic foot function. There were no significant differences in the navicular height (P = 0.54) in patients with KOA compared to that in the controls. The navicular height to foot length ratio (NHFLR), i.e. navicular height divided by the foot length, expressed as a percentage lacks a validated cut-off value for predicting flat feet and has a weak relationship with calcaneal angle, an important component of FPI-6. The FPI-6 consists of six parameters graded as –2 to +2. The respective normative FPI values for neutral, pronated, and supinated foot are 0 to ≤5, 5 to ≤12, and −12 to <0. The FPI-6 varies with age but is not affected by sex or BMI. FPI-6 correlates well with the navicular drop test and footprint parameters.
The footprint analysis systems have acceptable accuracy. The arch index (AI), Staheli AI (SAI), and NHFLR were used in footprint analysis in these studies. The AI is a ratio of the middle foot area to the entire foot area calculated from a simple ink or carbon print. AI is a reliable method that correlates well with navicular height and angular measures and is sensitive to age-related differences in foot posture. However, accurate calculation of footprint area requires graphics tablet or optical scanner and imaging software which can be time-consuming and may not be accessible at many centers. The validity of SAI (the ratio of the smallest medial to lateral width of the arch region divided by the greatest medial to lateral width of the heel region) in older adults and obese people is yet to be established. SAI is probably unable to differentiate between fat feet and flat feet of slender individuals. The value of SAI in the cavus foot is zero, making it difficult to correlate with knee pain in the cavus foot. The comparability of these three methods is not known.
BMI, age, and gender were not assessed in some of these studies. Obesity in adults distorts the footprint measures. The foot arch tends to be lower in elderly individuals, especially females. Older people have relatively pronated structure and dynamic foot function accompanied by less mobile feet leading to a higher prevalence of foot symptoms and disorders than young adults.
Foot and/or ankle pain, or stiffness (unilateral or bilateral, ipsilateral, or contralateral) is an inclusion criterion in the three OAI studies.,, The Framingham foot study showed that pronated foot posture is significantly associated with an increased likelihood of arch pain (odds ratio [OR] 1.38), and pronated foot function is significantly associated with generalized foot and heel pain (OR 1.28) in men. Supinated foot posture and function are protective against foot pain in women. Foot pain can be physiological (acute response to injury) or pathological and acute or chronic. The pain threshold is somewhat higher in elderly individuals. The risk factors for foot pain in elderly individuals include female sex, obesity, depression, diabetes mellitus, and osteoarthritis. It is hard to interpret that every elderly individual with ankle/foot pain has an abnormal foot posture. There are various other causes of foot pain such as inappropriate footwear, corns, callosities, and toe deformities were not excluded in the OAI studies. It should, however, be noted that the pronated foot posture is associated with an increased risk of hammertoes, overlapping toes, and hallux valgus, as observed in the Framingham foot study.
The OAI studies have included all subjects with knee pain. Approximately half of the patients with knee pain do not have radiographic KOA, while half of the patients with radiographic KOA do not have knee pain. About 25% of people over 55 years of age have painful knees, whereas only 10% of people over 55 years have painful OA with some disability. These findings indicate that every case of knee pain in the elderly is not KOA. As knee pain does not mean KOA and ankle/foot pain does not imply abnormal foot posture, it is difficult to draw conclusions related to this review from OAI studies.
Age, female sex, and obesity are the known risk factors for KOA. Increasing age is a risk factor for KOA, and the relationship is assumed to be linear though some studies have shown it to be non-linear with a high incidence between age 50 and 75 years in men. There is a higher risk of developing KOA in overweight and obese persons (OR 1.98, 95% CI for overweight; OR 2.66, 95% CI for obese persons than average-weight persons). BMI does not indicate the distribution of fat mass. A study of 770 OA cases revealed that 46% of them were obese (BMI ≥30), whereas 65% had central obesity (waist-to-hip ratio ≥0.90 in men or ≥0.85 in women). Central obesity is not measured in any of the studies selected for this review. Women are more likely to develop knee problems than men (OR 1.68 95% CI). The statistical analysis of some studies is presented after adjustment for age, sex, and BMI as covariates, whereas this method is not followed in the remaining studies. It is, therefore, difficult to conclude the association between pronated foot posture and KOA as these is the risk factors for both conditions.
A cross-sectional study of forty patients found that foot pronation as assessed by FPI-6 increases with radiographic progression of KOA. The varus alignment in KOA appears related to pronated foot posture. Cartilage damage in the medial compartment, as estimated with MRI, is significantly higher in higher grades of the pronated foot, and this association is linear (p for linear trend = 0.002). High planus feet (SAI >0.57) have higher incidence of cartilage damage as compared to those with SAI <0.57 (OR = 1.6; 95% CI, 1.1–2.2) and SAI = 0 (OR = 3.00 95% CI, 1.6–5.7). A recent systematic review of seventeen studies concludes that the hindfoot deformity improves after total knee replacement surgery in patients with KOA, except in patients with a rigid varus deformity. These findings indicate that the association between KOA and varus foot is linear.
Foot/ankle symptoms are responsible for worsening knee pain and are a risk factor for the development (OR 3.3) of symptomatic and radiographic KOA progression. Moreover, pronated foot in association with knee pain may lead to avoidance of physical activities resulting in weakness of the muscles and further deterioration of KOA. It is possible that pronation of the foot, a consequence of knee varus, is a biomechanical response for alleviation of knee pain. Lateral wedge support increases pronation and reduces pain in selected cases. A network meta-analysis of randomized controlled trials has shown that the use of a combined insole is most likely to reduce pain in KOA. It is, therefore, logical that foot assessment is done in all cases of MCKOA for pain management using correction of foot posture. Longitudinal studies are necessary to establish the risk of KOA in people with an asymptomatic or symptomatic pronated foot.
This is the first review of its kind revealing the relationship between foot posture and KOA. The search for this review was carried out by a single investigator (SW) under the supervision of the other investigator (RR). There may be a potential bias related to screening, selection, coding, and final analysis of the studies discussed in this review. A limited number of search engines, non-availability of full texts of some studies, and an exclusive selection of papers written in the English language may have led to the omission of a few relevant studies.
There is a small risk of selection bias in four of the selected studies,,, as per the “selection” domain of the NOS. There is a possibility of an “unclear risk” of measurement bias in these studies wherein FP was assessed using different methods.
The heterogenicity of the available studies is another serious limitation. The methodical differences include assessment of foot posture (FPI-6 vs. different footprint analysis methods) and compartment of KOA (medial, lateral, patellofemoral), an admixture of cases with medial and lateral compartment,, analysis of the same group of subjects with different methods,,, the study of ankle/foot pain rather than posture,,, and study of knee pain instead of OA., The validity and reliability of various assessment methods of foot posture have been previously discussed, and it is not known whether they are comparable. The radiological assessment of KOA was done by an orthopedic surgeon in some studies and by KL grading in others. The medial compartment is not mentioned in the titles or abstracts of some studies, even though it is evident in the methods section.,,,
Age, gender, and BMI are potential confounders for these studies. Some studies,,,, used age, sex, and BMI as covariates for statistical analysis, while one study used bodyweight as a covariate. All the remaining studies did not consider age, sex, and BMI as covariates. Furthermore, as most of these studies are cross-sectional, it is difficult to establish the cause-effect relationship.
| Conclusion|| |
The significant limitations for this literature review are the quality of these studies, confounding, and methodological differences. This review has identified that there is a strong and linear association between pronated foot posture and MCKOA. Knee pain is more often associated with bilateral or contralateral foot pain. The assessment of foot posture is necessary for all patients with MCKOA because customized foot orthoses may reduce knee pain in some patients. Longitudinal cohort studies are necessary for a better understanding of the correlation between foot posture and function and the development and progression of MCKOA. Other confounders such as occupation, lifestyle, primary footwear, and ankle/foot injuries also need to be analyzed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Cui A, Li H, Wang D, Zhong J, Chen Y, Lu H. Global, regional prevalence, incidence and risk factors of knee osteoarthritis in population-based studies. EClinicalMedicine 2020;29-30:100587.
Sharma L. Osteoarthritis of the knee. N Engl J Med 2021;384:51-9.
Silverwood V, Blagojevic-Bucknall M, Jinks C, Jordan JL, Protheroe J, Jordan KP. Current evidence on risk factors for knee osteoarthritis in older adults: A systematic review and meta-analysis. Osteoarthritis Cartilage 2015;23:507-15.
Hawker GA, King LK. Furthering the links between osteoarthritis and other health conditions. Rheumatology (Oxford) 2021;60:3964-5.
Jones RK, Chapman GJ, Findlow AH, Forsythe L, Parkes MJ, Sultan J, et al
. A new approach to prevention of knee osteoarthritis: Reducing medial load in the contralateral knee. J Rheumatol 2013;40:309-15.
Pasapula C, Shariff S, Cutts S, West J, Kobezda T. Adult acquired flat foot: A new biomechanical classification for the deformity based on two-point failure of the medial column. Clin Res Foot Ankle 2018;6:270-6.
Butterworth PA, Landorf KB, Gilleard W, Urquhart DM, Menz HB. The association between body composition and foot structure and function: A systematic review. Obes Rev 2014;15:348-57.
Banwell HA, Mackintosh S, Thewlis D. Foot orthoses for adults with flexible pes planus: A systematic review. J Foot Ankle Res 2014;7:23.
Paterson KL, Kasza J, Hunter DJ, Hinman RS, Menz HB, Peat G, et al.
The relationship between foot and ankle symptoms and risk of developing knee osteoarthritis: Data from the osteoarthritis initiative. Osteoarthritis Cartilage 2017;25:639-46.
Paterson KL, Kasza J, Hunter DJ, Hinman RS, Menz HB, Peat G, et al.
Longitudinal association between foot and ankle symptoms and worsening of symptomatic radiographic knee osteoarthritis: Data from the osteoarthritis initiative. Osteoarthritis Cartilage 2017;25:1407-13.
Levinger P, Menz HB, Fotoohabadi MR, Feller JA, Bartlett JR, Bergman NR. Foot posture in people with medial compartment knee osteoarthritis. J Foot Ankle Res 2010;3:29.
Gross KD, Felson DT, Niu J, Hunter DJ, Guermazi A, Roemer FW, et al.
Association of flat feet with knee pain and cartilage damage in older adults. Arthritis Care Res (Hoboken) 2011;63:937-44.
Abourazzak FE, Kadi N, Azzouzi H, Lazrak F, Najdi A, Nejjari C, et al.
A positive association between foot posture index and medial compartment knee osteoarthritis in moroccan people. Open Rheumatol J 2014;8:96-9.
Iijima H, Ohi H, Isho T, Aoyama T, Fukutani N, Kaneda E, et al.
Association of bilateral flat feet with knee pain and disability in patients with knee osteoarthritis: A cross-sectional study. J Orthop Res 2017;35:2490-8.
Surlakar SS, Sarfare BM, Ghodey S, Bhise S. Prevalence of altered foot posture in Osteoarthritis of knee. J Appl Adv Res [Internet]. 2017;2:144-9. Available from: http://dx.doi.org/10.21839/jaar.2017.v2i3.87
. [Last accessed on 2021 Mar 02].
Tribhuvan S, Kulkarni N. Correlation between foot posture index (FPI) and knee osteoarthritis (OA) in elderly individuals. Physiother Phys Educ 2019;4:39-43.
Chen Z, Shen Z, Ye X, Wu J, Wu H, Xu X. Association between foot posture asymmetry and static stability in patients with knee osteoarthritis: A case-control study. Biomed Res Int [Internet]. 2020, Article ID 1890917, 8 pages, 2020. https://doi.org/10.1155/2020/1890917
Akaltun MS, Koçyiğit BF. Assessment of foot posture and related factors in patients with knee osteoarthritis. Arch Rheumatol 2021;36:267-73.
Paterson KL, Hinman RS, Hunter DJ, Wrigley TV, Bennell KL. Impact of concurrent foot pain on health and functional status in people with knee osteoarthritis: Data from the osteoarthritis initiative. Arthritis Care Res (Hoboken) 2015;67:989-95.
Menz HB, Dufour AB, Riskowski JL, Hillstrom HJ, Hannan MT. Association of planus foot posture and pronated foot function with foot pain: The Framingham foot study. Arthritis Care Res (Hoboken) 2013;65:1991-9.
Wang Y, Teichtahl AJ, Abram F, Hussain SM, Pelletier JP, Cicuttini FM, et al.
Knee pain as a predictor of structural progression over 4 years: Data from the osteoarthritis initiative, a prospective cohort study. Arthritis Res Ther 2018;20:250.
Modesti PA, Reboldi G, Cappuccio FP, Agyemang C, Remuzzi G, Rapi S, et al.
Panethnic differences in blood pressure in Europe: A systematic review and meta-analysis. PLoS One 2016;11:e0147601.
Kanamoto T, Mae T, Yokoyama T, Tanaka H, Ebina K, Nakata K. Significance and definition of early knee osteoarthritis. Ann J 2019:5:1-4.
Gonçalves FB, Rocha FA, Albuquerque RP, Mozella AP, Crespo B, Cobra H. Reproducibility assessment of different descriptions of the Kellgren and Lawrence classification for osteoarthritis of the knee. Rev Bras Ortop 2016;51:687-91.
Culvenor AG, Øiestad BE, Hart HF, Stefanik JJ, Guermazi A, Crossley KM. Prevalence of knee osteoarthritis features on magnetic resonance imaging in asymptomatic uninjured adults: A systematic review and meta-analysis. Br J Sports Med 2019;53:1268-78.
Roemer F, Felson DT, Stefanik JJ, Rabasa G, Crema G, Wang MD, et al.
Heterogeneity of cartilage involvement in knees with radiographic disease severity kellgren-lawrence 2 and 3: The MOST study. (Conference Abstract), OARSI connect '21, world virtual congress on osteoarthritis. Osteoarthritis Cartilage 2021;29:S332-3.
Menz HB, Fotoohabadi MR, Wee E, Spink MJ. Visual categorisation of the arch index: A simplified measure of foot posture in older people. J Foot Ankle Res 2012;5:10.
Ohi H, Iijima H, Aoyama T, Kaneda E, Ohi K, Abe K. Association of frontal plane knee alignment with foot posture in patients with medial knee osteoarthritis. BMC Musculoskelet Disord 2017;18:246.
Redmond AC, Crane YZ, Menz HB. Normative values for the foot posture index. J Foot Ankle Res 2008;1:6.
Zuil-Escobar JC, Martínez-Cepa CB, Martín-Urrialde JA, Gómez-Conesa A. Evaluating the medial longitudinal arch of the foot: Correlations, reliability, and accuracy in people with a low arch. Phys Ther 2019;99:364-72.
Kodithuwakku Arachchige SN, Chander H, Knight A. Flatfeet: Biomechanical implications, assessment and management. Foot (Edinb) 2019;38:81-5.
Wearing SC, Grigg NL, Lau HC, Smeathers JE. Footprint-based estimates of arch structure are confounded by body composition in adults. J Orthop Res 2012;30:1351-4.
Bertani M, Soares D, Rocha E, Machado L. Foot arch differences in elderly people at standing: Considering gender and age. J Nov Physiother Rehabil 2017;1:34-8.
Menz HB. Biomechanics of the ageing foot and ankle: A mini-review. Gerontology 2015;61:381-8.
Hawke F, Burns J. Understanding the nature and mechanism of foot pain. J Foot Ankle Res 2009;2:1.
Menz HB. Chronic foot pain in older people. Maturitas 2016;91:110-4.
Hagedorn TJ, Dufour AB, Riskowski JL, Hillstrom HJ, Menz HB, Casey VA, et al.
Foot disorders, foot posture, and foot function: The Framingham foot study. PLoS One 2013;8:e74364.
Peat G, McCarney R, Croft P. Knee pain and osteoarthritis in older adults: A review of community burden and current use of primary health care. Ann Rheum Dis 2001;60:91-7.
Castano Betancourt M, Marchi E, Lipay M. Associations of central obesity with earlier onset of osteoarthritis symptoms. Osteoarthritis Cartilage 2021;29:S20-1.
Dadia S, Singh S. Influence of different grades of knee osteoarthritis on foot posture. Indian J Physiother Occup Ther An Int J 2014;8:14-8. 10.5958/j.0973-5674.8.1.004.
Al-Bayati Z, Coskun Benlidayi I, Gokcen N. Posture of the foot: Don't keep it out of sight, out of mind in knee osteoarthritis (Abstract). Gait Posture 2018;66:130-4.
Burssens A, De Roos D, Barg A, Welck MJ, Krähenbühl N, Saltzman CL, et al.
Alignment of the hindfoot in total knee arthroplasty: A systematic review of clinical and radiological outcomes. Bone Joint J 2021;103-B: 87-97.
Van Ginckel A, Hall M, De Ridder R. Comparative efficacy of biomechanical treatments on knee osteoarthritis pain: A network meta-analysis of randomized controlled trials (Conference Abstract), OARSI connect '21, world virtual congress on osteoarthritis. Osteoarthritis Cartilage 2021;29:S79-80.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]