A Review of Prevalence and Relationship to Functional Impairment and Falls
ABSTRACT
Falls in older people are common and may lead to considerable disability in this age-group. Although a number of risk factors for falling have been identified, the role of foot problems has received relatively little attention in the literature. This paper reviews the relevant literature pertaining to the prevalence of foot pathology in older people, and discusses the relationship between foot pathology, functional impairment and falls. In addition, a number of theoretical considerations regarding specific foot conditions and postural instability are outlined.
INTRODUCTION
Falls in older people are common and present a major public health concern. Approximately one third of people over the age of 65 years will experience a fall every year 1-3, and in many cases the injuries sustained from these falls have a significant detrimental impact on physical function and increase the risk of admission to nursing homes 4,5. A number of lower extremity risk factors for falling have been identified, including knee osteoarthritis 6,7, peripheral sensory loss 8,9, lower limb muscle weakness 10-12 and inappropriate footwear 13,14 (see Figure 1). However, the role of foot pathology in contributing to functional impairment and subsequent risk of falling has not been widely evaluated.
The human foot has an important and complex role in the maintenance of efficient locomotion. The foot provides the only source of direct contact with the ground when walking, and contributes to both the absorption of impact after heel contact and the generation of power required for forward momentum. Each of these functions requires the complex interaction of joint motions at specific times if smooth transferral of bodyweight is to be achieved. As such, it is reasonable to expect that foot dysfunction may interfere with normal progression of the body during walking, and may therefore be a contributing factor to functional disability and falling in older people. The aim of this paper is therefore to review the relevant literature pertaining to the prevalence of foot pathology in older people and its relationship to functional impairment and falling, and to discuss some theoretical considerations regarding specific foot conditions and postural stability.
Prevalence of foot pathlogy in older people
Lower extremity pathology has long been regarded as having a very high prevalence in older people 15,16. However, reliable data on the prevalence of foot problems in large samples of older people is lacking, and the studies which have been undertaken have reported quite variable findings. Establishing the prevalence of foot pathology in older people is a deceptively difficult issue due to the lack of consensus as to what actually constitutes a ‘foot problem’, variations in the populations which have been assessed, and the variety of approaches utilised to collect the data. Foot pathology in older people may result from age-related decreases in joint range of motion 17,dermatological conditions 18, detrimental effects of footwear 19-22 and systemic conditions such as peripheral vascular disease 23 diabetes mellitus 24-26 and arthritic changes 27,28. Furthermore, the definition of a foot problem may also include an individual’s inability to maintain basic foot hygiene (eg: cutting toe-nails) or difficulty in purchasing comfortable shoes 29,30. Research into the prevalence of these problems can be divided into two main groups; those which use foot specialists to directly assess the presence of the condition or problem, and those which rely on self-reporting by the subject. In addition, these studies must be further categorised according to the sample population evaluated (ie: in institutional care, a clinical setting, or community-dwelling).
Many investigations into foot problem prevalence in older people have focused on the objective documentation of the presence of lesions and structural deformity, in order to determine the need for chiropody / podiatry services in nursing home or residential care facilities. An early study of 1,011 nursing home residents by Merrill et al 31 reported that 25% suffered from corns, 23% from hallux valgus, and 14% from calluses. Females had a higher prevalence of these conditions than males. However, only 44% of patients were receiving podiatric care, suggesting a need to educate nursing staff as to the need for treatment of these conditions.
In an attempt to more accurately quantify structural foot deformities in older people, Hung et al 32 evaluated 166 hospital in-patients over the age of 65, using clinical observations, a footprint mat and goniometric assessments of joint position and range of motion. Fifty percent of subjects were found to have at least one foot deformity. The most common clinically observed structural deformities were hallux valgus (20%) and digital deformity (20%). With regard to joint range of motion, 40% exhibited a limitation in total foot eversion, and 70% exhibited a limited range of ankle joint dorsiflexion. However, only 7% of subjects reported foot discomfort despite the high prevalence of these deformities. Unfortunately, the results of this investigation pertaining to prevalence of structural deformities need to be viewed cautiously, as no data were provided regarding the reliability of the goniometric assessments. Recent investigations have suggested that goniometric measurements of the foot and ankle have moderate to poor reliability 33-36.
A similar study by Helfand et al 37 evaluated subjective foot complaints and clinically determined foot problems in 417 older people (age range 61 to 97 years) living in residential care facilities, and reported that 84% had one or more subjective foot complaints, 84% presented with one or more dermatological conditions affecting the foot, and 86% presented with one or more orthopaedic foot deformities. The most common subjective complaint was pain in the foot, followed by swelling, corns and calluses and bunions. The clinical assessments revealed the most common dermatological condition to be calluses and onychomycosis, while the most common orthopaedic deformities were hallux valgus, abnormal medial arch structure and prominent metatarsal heads. Given that the reliability of clinical assessment of arch height has been previously reported to be poor 38, the finding of ‘abnormal medial arch structure’ could be questioned, and may explain the higher prevalence of deformity reported in this study as compared to Hung et al 32.
Numerous investigations have evaluated the prevalence of foot problems in clinical populations. An early study conducted by Hsu 39 reported that the majority of foot problems in 426 older people attending a hospital foot clinic related to nail and skin disorders (36%). Similarly, Ebrahim et al 40 assessed foot problems in 100 older hospital inpatients, and reported that 66% had difficulty cutting their toenails, 49% exhibited pitting oedema and 39% had lesser toe deformities. However, only 19% complained of painful feet, and these subjects did not have appreciably more foot problems. This suggests that the presence of visible foot deformity may not necessarily correlate with development of symptoms.
The role of diabetes in the development of foot problems in older people is unclear. Crawford et al 41 assessed the prevalence of foot pathology in 248 people aged 75 years or older who were currently receiving podiatric treatment. The three most frequently reported problems were difficulty with cutting toenails (96%), corns (48%), and calluses (36%). A comparison of these results with older people not receiving podiatry treatment revealed a higher incidence of diabetes, rheumatoid arthritis and vascular disease in those receiving podiatric treatment. However, similar studies on clinical populations by Evans et al 42 and Plummer and Albert 43 reported equivalent rates of foot problems in older people with and without diabetes, suggesting that all older people should be provided with similar foot care screening and treatment. This is perhaps not surprising when it is considered that the normal ageing process leads to deficits in vascular 23 and sensory function 44 not dissimilar to the effects of diabetes on younger people.
Although these investigations suggest a very high prevalence of foot problems in older people, their generalizability is limited due to sampling bias. Clearly, rates of foot problems obtained from frail older people in institutional care or from those attending health clinics cannot be considered representative of older people in the general community. In an attempt to determine the prevalence of foot problems in community-dwelling older people, numerous investigations have been performed. In the early 1960s, a large three-year study was conducted by Helfand 45 which assessed general health and foot problems in 1,366 older people from a range of community seniors groups. The most commonly observed problems were hyperkeratosis (78%), dry skin (65%) and mycotic nail infection (56%). A subsection of the survey inviting subjects to report foot complaints revealed the most common concern was generalised foot pain (74%), followed by corns (56%), calluses (56%) and foot swelling (39%).
In contrast to the high prevalence of both objective and subjective foot problems reported by Helfand 45, a discrepancy between observed conditions and subjective concerns was reported by Cartwright and Henderson 29, who conducted a survey to determine the chiropody needs of 382 community-dwelling people over the age of 65 years in the United Kingdom. Results revealed that while 52% of subjects perceived they had a foot problem, the podiatrists reported a much larger figure of 84%. The most common problems reported by the subjects were difficulty in cutting toenails, nail problems, corns, aching or swollen feet and bunions. In addition to these common conditions, the podiatrists frequently diagnosed lesser toe deformities, varicose veins, osteoarthritis, pronated foot and oedema. The reliability of the podiatrists’ observations ranged from good to poor, which questions the view that information obtained from clinical assessments is more valid than self-reporting of foot problems.
Elton and Sanderson 46 employed chiropodists to assess 999 older people in the community, and reported that while 71% were diagnosed with a foot problem, only 27% of these had previously sought treatment. Whether this discrepancy represents unmet need cannot be determined, as no information was obtained regarding the subjective concerns of the subjects. A similar study by White and Mulley 47 employed podiatrists and a medical practitioner to clinically assess the presence of foot problems in 96 people aged over 80 years living in their own homes, and reported that 70% had difficulty in maintaining basic foot care. Only six subjects were considered by the examining clinician to have ‘normal healthy feet’. The most common problems observed were corns or calluses (68%), nail pathology (56%), lesser toe deformities (48%) and hallux valgus (34%). However, only 30% of subjects experienced pain in their feet.
More recently, a large community-based study by Harvey et al 48 randomly assessed 792 people aged 60 years and over for toe deformities, corns and calluses, ingrowing toenails and toenail thickening, and reported that 53% of the study population had three or more of these foot problems. An evaluation of foot care practices revealed that 40% of the subjects requiring foot treatment did not receive any specialised care. The authors concluded that although foot problems are prevalent in older people, provision of foot care services is a low priority in the National Health Service in the United Kingdom.
These findings provide further insight into the prevalence of foot problems in the general community, however, it has been suggested that much larger studies need to be undertaken to determine the true epidemiology of foot problems in older people. The largest investigations regarding foot problem prevalence in the community have been performed in the United States, generally as part of broader evaluations of overall health status. As part of a large-scale hypertension screening program in Florida, 733 home-dwelling subjects over the age of 65 years (mean age 80 years) completed a questionnaire which included a section regarding presence of foot problems. Sixty percent of females and 32% of males reported that they were troubled by foot problems. Commonly reported foot conditions were toenail problems (22%), calluses (20%), corns (16%), dry skin (15%) and bunions (13%). Females reported a significantly higher prevalence of corns and bunions than males 49.
The most recent large scale investigations were the National Health Interview Survey, undertaken by the US Public Health service, and a study by the marketing communications company BrimmComm, acting on behalf of a coalition of different organisations including the American Podiatric Medical Association. The NHIS involved face to face interviews of 119,631 individuals, while the BrimmComm study evaluated 1,003 individuals by telephone. For subjects over the age of 65, the prevalence of foot problems for the NHIS and BrimmComm studies were 31 and 38% respectively. With regard to specific foot problems, the findings of each of the studies are in close agreement; the most commonly reported conditions were (in descending order) corns and calluses, nail disorders, hallux valgus and foot infections 50.
It is evident from the above discussion that studies which utilise foot specialists to directly assess the subjects for the presence of a foot problem generally report higher prevalence than those which rely on self-reporting of foot problems. This may be due to the common observation that many older people consider foot disorders an inevitable part of the ageing process, and therefore do not report them to health care professionals 51. A recent survey of 128 people over the age of 65 years found that although 71% of the subjects suffered from foot problems, only 26% identified foot pathology as a medical condition 52. As such, it could be argued that foot pathology is only perceived as a serious problem in older people if it significantly impacts on their ability to perform basic activities of daily living.
Gender and age-related differences in the prevalence of foot problems are clearly evident from the available literature. There is a general consensus that females both develop and report more foot problems than males. This has been attributed primarily to the influence of fashion footwear commonly worn by females, which has been found to contribute to foot pathology due to the detrimental effect of high heels and a narrow toe-box 19,20,22,53. The prevalence of foot problems tends to increase significantly with advancing age, and this has been attributed to the cumulative effect of chronic systemic diseases which affect the integrity of anatomical structures in the foot 32,41,47,49.
Foot pathology and functional impairment
Although the high incidence of foot problems in older people is widely recognised and reasonably well supported in the literature, the contribution of foot problems to both functional impairment and postural instability has not been examined in detail. In many cases, support for a relationship between foot pathology and mobility impairment is derived from large-scale studies of general health status which reveal associations between the presence of foot problems and self-reported impairment. Nevertheless, a number of recent studies do provide some evidence to support this long-accepted (and plausible) assumption.
In the epidemiological study of 733 people over the age of 72 years by Black and Hale 49 it was reported that 9% of subjects indicated that their daily activities and lifestyle were impaired by their foot problems, with females reporting greater impairment than males. Similarly, Cartwright and Henderson 29 reported that 4% of 382 older people felt that foot trouble contributed to their disability, and 20% of those who were housebound blamed this on foot problems. These relatively low figures, however, must be interpreted in light of whether older people are aware of the possible functional implications of foot impairment. It has been suggested that because many older people consider foot problems a normal accompaniment of ageing, they are more likely to attribute their immobility to other, more easily recognisable factors 53.
More recently, Benvenutti et al 30 assessed the level of disability in performing activities of daily living in 459 residents over the age of 65 in a small Italian town. A significant association was found between the presence of a clinically assessed foot problem and self-reported difficulty in performing basic activities such as cutting their own toenails, performing housework, shopping and walking 400 metres. In addition, a short gait evaluation revealed that subjects with foot pain required a greater number of steps and more time to walk three metres than those free of foot pathology. The authors suggested that assessment and treatment of foot problems may prevent foot pain and potentially reduce the risk of disability.
The suggestion that lower limb problems may influence gait speed has been investigated by a number of authors. Bendall et al 55 assessed factors affecting walking speed of 67 subjects over the age of 65 years, and reported that the presence of leg pain was significantly associated with a reduction in the speed of walking. Unfortunately, foot pain or the contribution of foot dysfunction to leg pain was not addressed. Similarly, a longitudinal study of 588 people over the age of 60 years by Gibbs et al 56 assessed the relationship between physical impairments and walking velocity, and reported that the best predictors of slowed gait function were reduced quadriceps muscle strength, and joint impairment (tenderness, deformity or limitation of motion) in the lower spine, hips, knees, ankles and feet. Unfortunately, lower extremity joint impairment was a single variable in this investigation, so it is unclear as to the relative contribution of each specific anatomical region.
In addition to the impact of foot pathology on gait, a paper by Guralnik et al 57 suggests that diminished lower extremity function may have even broader functional significance. In this large prospective study, 5,174 community-dwelling people aged over 71 years were followed for 6 years, and underwent assessments of general health status, medication usage and physical abilities. Lower extremity functional status was measured using standing balance tests, walking velocity and ability to rise from a chair. Comparison of these results to self-reported physical capabilities and general health status revealed that measurement of lower extremity function characterises older people over a wide spectrum of functional status, and is capable of predicting both nursing home admission and mortality.
Therefore, although more work needs to be done to clarify the relationship between foot pathology and functional disability, these investigations provide some evidence to support the widely held view that foot and leg problems contribute to functional impairment in physical activities, and may therefore affect quality of life in older people.
Foot pathology and falls
Given that the foot provides the structural foundation for both static support and progression of the body during locomotion, it is also reasonable to suggest that foot impairment may be a contributing factor to postural instability and falling in older people. In 1958, De Largy 58 suggested that hammertoe deformities, exostoses, metatarsal problems, fracture and other orthopaedic deformities may lead to inactivity and subsequent weakness and falls. The author also suggested that the importance of podiatry in the prevention of falls resulting from foot problems is often under-emphasised. Similarly, both Helfand 59 and Gibson et al 4 have suggested that painful foot lesions and structural foot deformities may contribute to a fall by detrimentally altering the foot’s functional base of support.
While the suggestion that people with foot problems are more likely to experience balance difficulties is logical and plausible, few studies have adequately addressed this issue. A retrospective investigation of 125 older subjects who had fallen by Wild et al 60 revealed that those who fell had a higher prevalence of muscle weakness and foot disorders than an age-matched control group. Similarly, a retrospective investigation of 1,042 community-dwelling older people by Blake et al 6 reported a higher prevalence of undefined ‘foot trouble’ in those who had fallen previously, and Dolinis and Andrews 7 reported that the presence of a corn or bunion was an independent risk factor for falling (odd ratio = 1.4) in 1,947 community-dwelling older people.
Three prospective investigations provide further evidence that the presence of foot problems may increase falls risk. Gabell et al 14 evaluated predisposing causes to falling in 100 subjects over the age of 65, and reported that the probability of experiencing a fall increased threefold in the presence of an undefined ‘minor foot problem’. However, self-reported foot pain was not a discriminating factor between fallers and non-fallers. Similarly, Tinetti et al 1 conducted a prospective investigation of 336 community-dwelling people over the age of 75 years, and reported that the presence of a severe bunion, toe deformity, ulcer or deformed nail (recorded as a ‘serious foot problem’) was a small (odds ratio = 1.8) but statistically significant risk factor for falling. However, foot problems were not an independent risk factor for falls after use of sedative medications and presence of cognitive impairment were included in the logistic regression analysis. Furthermore, it is unclear what criteria were employed to classify a bunion deformity as ‘severe’, and whether a nail deformity can be justifiably classified as a ‘severe foot problem’ could be questioned.
Finally, a recent prospective investigation by Koski et al 61 was undertaken to determine predictors of falls in 979 home-dwelling subjects over the age of 70 years in Finland. The presence of a foot problem (defined simply as the presence of a ‘bunion’) was found to be a significant risk factor (odds ratio = 2.0) for falls leading to major injuries in women, but not in men. Unfortunately, the authors did not report the criteria utilised to diagnose the presence of a ‘bunion’, nor was any classification of the severity of the deformity attempted.
Although these results suggest that foot problems may be a risk factor for falling, one of the difficulties in interpreting the significance of generalised ‘foot problems’ is that some degree of foot pathology is very common in all older people. An investigation by Speechley and Tinetti 62 sought to determine three subgroups of older people – frail, vigorous or ‘transition’ – based on demographic, physical and psychological assessments, and correlate these with risk of falling. Results revealed that even amongst the most vigorous subjects, some pathology was observed. Prevalence of undefined ‘serious foot problems’ was very similar across the three functional subgroups, despite the finding that the frail group were much more likely to fall than the vigorous group. This study highlights the need for further falls investigations to adequately define and categorise specific foot pathologies and their severity, rather than simply recording ‘foot problems’ as present or absent.
Specfic Foot conditions and postural instability- some theoretical considerations
No studies in the literature have adequately evaluated the effect of specific foot pathologies on postural stability. Nevertheless, plausible explanations as to how certain foot conditions can lead to balance deficits can be developed by drawing inferences from the available information on the mechanical and somatosensory contributions to postural stability. Theoretical considerations regarding the contribution of three common foot problems (hallux valgus, lesser digital deformity and restricted joint mobility) to postural instability are provided below.
Hallux valgus
Hallux valgus is the condition in which the first metatarsophalangeal joint is progressively subluxed, often leading to lateral displacement of the hallux. The aetiology of the condition is multi-factorial, involving hereditary, biomechanical and footwear-related factors 63,64. Although the exact incidence of the condition is unknown, it is believed to be the most common structural disorder affecting the first ray segment of the foot, and is one of the most common foot problems observed in older people. The two largest epidemiological studies revealed the condition to be the third most common foot problem after corns and calluses and nail disorders 50.
The effect of hallux valgus on foot function has been studied extensively, primarily by the use of pedobarograph systems which enable the evaluation of the timing and magnitude of vertical pressures applied to the sole of the foot. Grundy et al 65 evaluated plantar pressures in ten subjects with normal feet and four with ‘gross’ hallux valgus, and reported that the hallux valgus subjects exhibited less loading on the toes and a more lateral deviation of the centre of pressure pathway through the foot. Similarly, investigations by Stokes et al 66 and Hutton and Dhanendran 67 compared plantar pressure in normal subjects and subjects with hallux valgus and reported that the presence of hallux valgus caused a comparative decrease in pressure applied to the toes and a more lateral displacement of the centre of pressure. Hutton and Dhanendran state that these findings suggest that in subjects with hallux valgus, the normal loading of the first metatarsophalangeal joint does not occur, which leads to a decreased ability to actively propel the body forward.
Whether these changes in foot function have detrimental effects on postural stability is unknown, however, it could be suggested that changes in first metatarsophalangeal joint function may affect the transferral of bodyweight during the propulsive phase of gait. The first metatarsophalangeal joint provides the final ‘pivot’ over which the body moves during propulsion, and is known to be important for maintaining the body’s forward momentum 68. The deviation of the hallux associated with the condition clearly affects the transferral of pressure through the foot, which suggests that hallux valgus may affect the displacement of the centre of gravity in a detrimental manner,
Digital deformity, such as hammertoes, retracted toes and clawtoes, are one of the most common foot pathologies in older people. The aetiology of lesser digital deformity is also thought to be multi-factorial, involving age-related changes in joint range of motion, changes in the line of action of long flexor and extensor tendons, and occlusion by poorly fitting footwear 69. While there are some morphological differences between hammertoes, clawtoes and retracted toes, in each case the deformity alters the normal weightbearing function of the toes during gait. In particular, the retracted toe deformity, caused by contracture of the long extensor tendons, may result in the digits becoming completely non-weightbearing during gait.
Digital deformities may affect balance by reducing somatosensory input from the toes or by altering the mechanical stability of the foot. The importance of digital pressure in standing balance was highlighted in an investigation by Tanaka et al 70. In this study, the tactile sensitivity of the toes, peak pressure exerted by the toes and postural sway in unipedal stance was measured in 15 healthy young subjects. The results revealed a significant linear relationship between the postural sway parameters and the pressure exerted by the toes. A subsequent investigation by the authors compared a group of young subjects (mean age 21 years) and older subjects (mean age 71 years) and found that the older group exhibited less tactile sensitivity of the great toe, greater standing postural sway and increased great toe pressure 71. These results suggest that older people require greater force to be exerted by the toes to stabilise standing posture than younger people. Therefore, the absence of toe pressure due to the presence of digital deformity may lead to balance impairment.
Further evidence to support the importance of toe contact in the maintenance of balance is provided by an investigation by Mueller et al 72. In this study, 15 subjects with transmetatarsal amputation were compared to 15 normal control subjects in a number of physical performance tests including the Functional Reach Test (FRT). The FRT is a measure of balance which assesses the maximal distance that a person can reach forward while maintaining a fixed base of support in a standing position. Results revealed that subjects with transmetatarsal amputation performed significantly worse on the FRT than the controls, which was attributed to the absence of digital function and associated loss of foot strength.
Finally, gait studies reveal that the toes accept a large proportion of bodyweight prior to the foot leaving the ground, which may be important in maintaining balance when walking 65,73,74. Therefore, it is possible that the presence of digital deformity, due to the reduction in toe contact during gait, may affect balance by reducing the level of somatosensory input to the brain regarding foot position, and by causing mechanical instability during propulsion.
Restricted joint mobility
It is widely recognised that the foot plays a major role in adapting to uneven terrain, and that postural corrections by the joints of the foot and ankle significantly contribute to the maintenance of postural stability. As such, limitations in joint range of motion associated with ageing may affect an individual’s ability to maintain stable posture in standing and walking activities. Age-related reduction in foot and ankle range of motion has been reported by Nigg et al 17, who found a significant difference in foot and ankle range of motion when comparing subjects aged 20-39 years of age to subjects 70-79 years of age. Of particular interest, the authors reported a highly significant reduction in eversion range of motion in women associated with increasing age. Similarly, investigations conducted by James and Parker 75 and Vandervoort et al 76 both reported significant age-related reduction in ankle joint dorsiflexion range of motion.
The effect of age-related changes in range of motion on postural stability has not been directly evaluated in the literature, however mathematical modelling work by Hoogvliet et al 77 and in-vivo studies by Matsusaka 78 and Gauffin and Tropp 79 suggest that inversion and eversion movements of the foot and ankle are important for controlling posture in the frontal plane in single limb stance. This suggestion is supported by the observation that subjects who have undergone surgical fusion of the subtalar joint 80 or talo-navicular 81 joint have difficulty walking on uneven ground.
Two studies have suggested that loss of range of motion in the joints of the foot may be a contributing factor to falls in older people. A small retrospective study by Studenski et al 82 reported that 10 subjects with a history of falling had significantly smaller range of ankle plantarflexion compared to 24 controls who had not fallen. Furthermore, Cummings et al 83 reported that older Chinese women who had their feet bound from childhood exhibited marked disability in functional tasks such as walking, rising from a chair and squatting, and were also more likely to fall that those who have not had their feet bound.
Although further research is required to support a causal link between restricted joint mobility, instability and falls, these studies suggest that age-associated loss of joint range of motion in the foot may affect postural stability by diminishing the ability of the foot to adapt to changes in terrain.
Treatment of foot pathology to prevent falls
Despite the relatively limited evidence in the literature as to the contribution of foot problems to falling, a large number of authors have suggested that treatment of foot pathology is an important component of a falls prevention program 4,7,59,84-86. In addition, foot care specialists have been employed in multi-disciplinary clinics specifically designed for older people at risk of falling. Wolf-Klein et al 87 reported that 77% of 36 subjects with a history of falling had not experienced another fall in the subsequent 12 months following treatment in a multi-disciplinary falls clinic. The clinic employed a geriatrician, neurologist, cardiologist, physiatrist, audiologist, ophthalmologist and podiatrist. Foot-related problems treated by the clinic included hammertoes, calluses, and footwear modifications. Similarly, a falls and balance clinic established by Hill et al 85 involved treatment of foot and footwear problems in 10% of cases. Although the efficacy of such a clinic in preventing falls was not fully investigated, the authors suggested that six-monthly audits of the clinic may clarify the role of multi-disciplinary care in falls prevention.
The potential role of the foot care specialist in falls prevention clinics could involve both patient education and therapeutic interventions. Firstly, wearing inappropriate footwear has been found to be exacerbate postural instability 89-92 and is associated with an increased risk of falling 13,14,93,94. Given that many older people are unaware of the dangers of ill-fitting footwear 93,95, appropriate advice as to the features of a ‘safe’ shoe may prevent the contribution of this unnecessary risk factor. Secondly, routine palliative treatment of corns and calluses may decrease foot pain and therefore improve mobility 16,30,96. Finally, recent studies suggest that foot orthoses may have beneficial effects on postural stability by improving mechanical stability of the foot and enhancing proprioceptive awareness of foot position 97-99. Although no studies have been undertaken to specifically evaluate the effects of foot orthoses on postural stability in older people, this intervention may be of some benefit and therefore warrants further investigation.
Conclusions
The available literature suggests that foot problems, in particular calluses, hallux valgus and lesser digital deformity, are very common in older people, and may contribute to functional impairment and falls in this age group. However, while the literature suggests a relationship between foot impairment and falls, the underlying mechanisms responsible for this relationship have not been adequately assessed. Foot pathology has generally been poorly defined in falls studies, in many cases being coded as a single variable (ie: presence or absence) or clustered together with other pathologies and labelled ‘lower extremity problems’. This makes it difficult to delineate the contribution of specific foot conditions to falls, and raises the possibility that the contribution of more subtle foot problems has been overlooked. Plausible suggestions have been put forward regarding how hallux valgus, lesser digital deformity and restricted joint motion may affect postural stability, however in each case the suggestion is purely conjectural and not yet supported by sufficient evidence. Further research is therefore required to clarify whether specific foot conditions affect balance ability in older people, and whether therapeutic interventions by foot care specialists may decrease falls risk.
Paper written by:
Hylton B. Menz, B Pod (Hons)
Associate Lecturer
University of Western Sydney – Macarthur
PO Box 555
Campbelltown 2560
New South Wales, AUSTRALIA
Stephen R. Lord, BSc, MA, PhD
Research Fellow
Prince of Wales Medical Research Institute
High Street
Randwick 2031
New South Wales, AUSTRALIA
Address correspondence to:
Hylton B. Menz
Ph. (+ 61) 2 46203 759
Fax: (+61) 2 46203 792
