Table 5 Studies of foot function measures

Foot Function Index, 1991

Budiman-Mak, E [7]

Instrument Development

N: 87 (78 male)

Classical Test Theory

23 items

Visual Analog Scale

Good clinimetrics, applicable to various age groups and varieties of foot and ankle pathologies.

Mean age: 61

3 domains

Conclusion: Positive

(Range: 24–79)

Pain, difficulty and activity limitation subscales clinician

Dx: RA foot

Location: USA

Foot Function Index Pain (left/right), 1996

Saag, KG [23]

Foot Function Index pain scale; Compare right/left foot

N: 63 (13 male)

Classical Test Theory

9 items

Visual Analog Scale

This measure of right vs. left side of the foot showed good clinimetric properties

Mean age: 57.5 (SD=11.6)

FFI pain subscale

Conclusion: Positive.

Dx: RA

clinician

Location: USA

Foot Function Index/Foot Health Status Questionnaires (FHSQ), 1998

Bennet PJ [9]

Development of FHSQ, a new measure

N: 111 (25 male)

Classical Test Theory

13 items

Likert

FHSQ has good clinimetrics.

Mean age: 54 (SD=20)

4 domains clinician

Conclusion: Positive.

Dx: Osteoarthritis hallux valgus

Location: Australia

Foot Function Index/Ankle Osteoartitis Score (AOS), 1998

Domsic, RT [24]

AOS consisted of Foot Function Index pain and disability scales

N: 36 (12 male)

Classical Test Theory

18 items

Visual Analog Scale

AOS had good clinimetrics.

Mean age: 52.7 (Range: 16–79)

2 Domains clinician

Conclusion: Positive.

Dx: Ankle osteo-arthritis

Location: USA

Foot Function Index/Foot Function Index- 5pts in Dutch, 2002

Kuyvenhoven, MM [3]

Foot Function Index in Dutch

N: 206 (78 male)

Classical Test Theory

15 items

5-point Likert

Adaptation of Foot Function Index to 5 point Likert, used as a generic measure in foot and ankle problems.

Mean age: 61 (SD=10)

2 domains: pain & disability clinician

Conclusion: Positive.

Dx: OA with limited mobility and pain

Location: Netherlands

Foot Function Index/Foot Health Status Questionnaire (FHSQ), 2002

Landorf, KB [10]

Validation of FHSQ to Foot Function Index

N: 17 (4 male)

Non-parametric statistics

FHSQ

5-point Likert

FHSQ has less items than FFI and was printed in larger font for ease of use.

Mean age: 44.6 (SD=10.5) (Range 24–72)

13 items

Conclusion: Positive.

Dx: Painful plantar fasciitis

4 domains; clinician

Location: Australia

Foot Function Index/Foot Impact Scale (FIS), 2005

Helliwell, P [29]

Validation with Health Assessment Questionnaire (HAQ), FFI, and Manchester Foot Disability Questionnaires (MFDQ)

N: 148 (34 male)

Item Response Theory

FIS

Visual Analog Scale

FIS items were derived from RA patients (consisted of impairment/shoes and activities/participation subscales), with good clinimetric properties.

Mean age: 61.7 (Range 28–89)

51 items

Conclusion: Positive.

Dx: RA Foot Pain

2 domains

Location: UK

Patient

Foot Function Index, 2005

Agel, J [25]

Reliability and validity tests in specific population with moderate to high physical function

N: 54 (22 male, 6 unknown)

Correlation statistics

Foot Function Index

Likert Scale

Use of Foot Function Index in non-systemic foot and ankle problems requires removal of 2 items each from pain and disability, judged not applicable for this condition.

Mean age: 52.8 (SD=12.3) (Range 19–74)

23 items

Conclusion: Positive.

Dx: Non-traumatic foot/ankle complaints

3 domains

Location: USA

Foot Function Index, 2005

Shrader, JA [28]

Reliability and validity measures of navicular joint deformity vs. clinical findings

N: 20 (0 male)

Foot Function Index

Visual Analog Scale

Foot Function Index was used to measure the foot health status associated with joint deformities.

Mean age: 55.4 (SD=11.4 years); Dx: RA 12.7 years (SD=10.4)

Index 23 items

Conclusion: Positive.

Dx: Navicular joint dropped and foot pain

3 domains

Location: USA

Foot Function Index-R with Foot Function Index, 2006

Budiman-Mak, E [11]

Instrument Development

N: 97 (90 male)

Item Response Theory

Foot Function Index

Likert scale (replaced Visual Analog Scale)

Foot Function Index-R had 3 domains, plus 4^th psychosocial domain added to assess quality of life.

Mean age: 69 (range: 38–88)

68 items (long)

Conclusion: Positive

Dx: Chronic foot and ankle complain

34 items (short)

Location: USA

Clinicians and patients

Foot Function Index, 2006

Bal, A [26]

Comparing Foot Function Index with Health Assessment Questionnaires (HAQ) & SFC

N: 78 (11 male)

Correlation statistics

Foot Function Index

Visual Analog Scale

Strong correlations of HAQ and Foot Function Index scores, HR and CV also reflected in Foot Function Index scores and were highly correlated with Rand 36 items Short Form Health Survey (SF36).

Mean age: 50.65 (SD=10.7); RA duration 13.96 (SD=8.09)

23 items

Conclusion: Positive

Location: Turkey

3 Domains

Foot Function Index & SF36, 2006

SooHoo, N [27]

Validity test in foot health and general physical health

N:69 (25 male)

Correlation statistics

Foot Function Index

Visual Analog Scale

The 3 domains of Foot Function Index demonstrated moderate-high correlation with SF36, thus it was reasonable to use Foot Function Index to monitor outcomes.

Mean Age: 46 (Range 16–82)

23 items

Conclusion: Positive.

Dx: Foot & Ankle disorder

3 domains

Location: USA

Foot Function Index & American Orthopedic Foot and Ankle Society (AOFAS) hallux module, 2006

Baumhauer, JF [32]

Reliability and validity of test, compared with Foot Function Index

N:11 (1 male)

Correlation statistics

AOFAS hallux & lesser toes module

Numeric rating scale

Only AOFAS hallux for pain correlated with Foot Function Index pain scale.

Mean age: 54 (Range: 40–72)

Conclusion: Positive.

Dx: RA without foot complaints

Location: USA

Foot Function Index, 2006

Van der Leeden, M [30]

Measure forefoot damage

N:62 (15 male)

Correlation Statistics

Validation with Western Ontario Mac Masters Universities Osteoarthritis Index (WOMAC) and Disease Activity in 44 RA joints (DAS-44)

Numeric rating scale

Foot Function Index function subscale correlated with WOMAC and DAS-44. Foot Function Index pain score correlated with forefoot pain. Foot Function Index function score correlated with hind foot problem.

Mean age: 55.7 (SD=13.11)

Conclusion: Positive.

Dx: RA forefoot complaints, duration of 96 months

Location: Netherlands

Foot Function Index, American Orthopedic Foot and Ankle Society (AOFAS) clinical rating component, 2007

Ibrahim, T [33]

Testing the criterion validity of clinical rating components of AOFAS with Foot Function Index

N:45 (11 male)

Correlation Statistics

Validity of AOFAS scale

Numeric rating scale

The scores of AOFAS clinical ratings and Foot Function Index were moderately correlated based on 41% response rate.

Mean age: 55 years (range=15-81)

Conclusion: Positive.

Dx: Hallux deformities

Location: UK

Foot Function Index,/Foot Function Index Chinese (Taiwan), 2008

WU, SH [36]

Reliability and validity measure of PCS of SF-26, Taiwan version;

N:50 (planta fasciitis); mean age 46.9 (SD=10.6)

Cross-cultural adaptation

Foot Function Index

Visual Analog Scale

Foot Function Index Taiwan Chinese consisted of 21 items. Could measure non-traumatic and traumatic foot and ankle problems. The floor score was 10%, in sample with fractures.

N:29 (ankle/foot fracture); mean age 37.2 (SD=14.8) 25 male

21 items

Conclusion: Positive.

Location: Taiwan

3 domains

The order of items was changed.

Clinician and patient

Foot Function Index, Foot Function Index-D, 2008

Naal, FD [34]

Foot Function Index-D,

N:53 (14 male)

Cross-cultural adaptation

Foot Function Index-D

Numeric rating scale

Foot Function Index underwent German translation. Foot Function Index-D added 3 new items and revised 8 items of the Foot Function Index and had demonstrated good clinimetrics.

Age: 57.2 (SD=13.7) Range (18=77)

Index-D 18 items (pain & disability subscales)

Conclusion: Positive.

Dx: Foot complaints

2 domains

Location: Germany

Clinician and patient