Accurate assessment is essential in hip disability management in order to evaluate the progression of symptoms and functional limitation and to determine the efficacy of different treatments. This assessment may be carried out through several methods. In clinical practice increasing significance is given to measuring health and quality of life and numerous tools have been developed to measure both parameters.1 Functional evaluation scales provide information on the impact of the condition from the patient's viewpoint and are complementary to physical examination (mobility, strength, etc.) and the outcome obtained from imaging studies.2 Many questionnaires have been developed on an international scale to assess impact perceived by patients with hip disabilities. The majority of these questionnaires have been developed in English-speaking countries, which causes inconvenience when they are to be used in countries with different languages or cultures. An appropriate cross-cultural adaptation3,4 is necessary for them to be applied to patients of a different culture (a more complex process than simple translation) and validation of the scale,5 i.e. their reliability and validity must be established in the new linguistic groups in which they are to be applied.6 After Mandarin Chinese, Spanish is the second most spoken language in the world, with a broad geographical reach,7 both in countries which use it as an official language and those where it is used by immigrants residing in countries with different maternal languages.

In 2013 a review was made of questionnaires adapted into Spanish for patients with cervical and lumbar pain,8 but we have found no similar reviews for hip disabilities.

The aim of this article was to become acquainted with the cross-cultural adaptations of hip-specific patient-reported outcome measures in Spanish, with additional analysis of the methodological quality of the cross-cultural adaptation process and the psychometric properties of the new version obtained as a result.

We identified 8 relevant articles,15–22 which described 8 self-completion questionnaires cross-culturally adapted to the Spanish population and the clinimetric properties of which had been studied in the new version. Three questionnaires were applicable to any lower limb disability: Lower Limb Functional Index (LLFI)15; Lower Extremity Functional Scale (LEFS)16 and the questionnaire Arthrose des Membres Inférieurs et Qualité de vie (AMICAL).17 Three questionnaires were applicable to knee and hip disabilities: Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index18; Osteoarthritis Knee and Hip Quality of Life (OAKHQOL)19 and Hip and Knee Questionnaire (HKQ).20 Lastly, there were 2 specific hip questionnaires: Hip Outcome Score (HOS)21 and the International Hip Outcome Tool-33 (iHOT-33).22

In all cases the original questionnaire had been created in English, save in 2: AMICAL17 and OAKHQOL,19 designed in French. Our search was not able to locate any questionnaires which had been originally designed in Spanish.

Table 1 lists the demographic and clinical characteristics of the population in which each of the studies was carried out. The adapted scale, together with instruction for the patient, was included in the publication in all cases except for 2 questionnaires: WOMAC18 and iHOT-33.22

The majority of articles were published very recently. One of the adaptations was published in 201522 and 5 in 2014.15–17,19,21 The initial scale adapted into Spanish was the WOMAC, in 2004.18 This scale was adapted into Spanish for the first time in 1999,23 but did not then include the study of psychometric properties and was therefore excluded from our article selection.

All the questionnaires were validated in Spain, except one17 which was validated in Mexico. The number of patients was higher than the recommended 50 for this study type in all adaptations.

In general, the cross-cultural adaptation process of all scales required some minor modifications with respect to the original version. The main findings from assessment of the methodology used for cross-cultural adaptation are analysed in Table 2. Five questionnaires rigorously complied with the 5 steps of recommendations from international guidelines,16,17,19,21,22 the remainder were less strict in this regard. The pilot test was conducted in 6 scales,17–22 but only 221,22 did so with 30 patients.

The main psychometric properties analysed in the Spanish versions are shown in Table 3. No study assessed all the metric properties of the new version, In general, the authors’ conclusion regarding each of the adaptations made was that the psychometric properties assessed were acceptable and comparable with those of the original versions and other versions adapted into other languages.

Regarding reliability, internal consistency was assessed in all scales. For test-retest reproducibility only in four was time between scales specified17,18,21,22 and of these only in two17,18 was the number of patients to whom it was applied mentioned. One17 of them surpassed the ideal number of over 29 patients recommended for this assessment. The level of agreement was only analysed in two scales.21,22

Total internal consistency in all scales was above 0.7–0.8, sufficient value to guarantee their reliability. The ICC was very good in all cases. The level of agreement was analysed in two questionnaires.21,22 Seijas et al.21 analysed the MDC which was 13.7 for the daily life activities (DLA) subscale and 22.8 for the sports subscales, and the SEM was ±5.1 in DLA and ±8.5 for sports. Ruiz-Ibán et al.22 calculated the MDC and SEM values as 12.5 and 4.66, respectively.

Validity was assessed in all questionnaires. This varied according to the tools of comparison but was generally appropriate. The floor and ceiling effects were analysed in four questionnaires,16,20–22 with the ceiling effect being present in one21 and the floor effect in another.22

Sensitivity was examined in only three scales.16,21,22 In two of them only the SRM,21,22was measured and only in one16 were values for SE and SRM available, which indicated great sensitivity in both cases.

In the AMICAL17 questionnaire the cross-cultural adaptation was carried out in a Latin American country (Mexico). There were no marked cultural differences to hinder the use of the questionnaire in Spain. The introduction of minor changes in some of the words used enable usage. For example, the word “pesero” (cab) could be replaced with “autobús” (bus).

Our aim was to systematically review the self-completion questionnaires for hip disability adapted into Spanish by analysing the methodological quality of the cross-cultural adaptations and verifying the psychometric properties of the new version obtained. Whilst reviewing we found eight questionnaires which had been adapted into Spanish.15–22 In all cases the adaptation procedure had been accurately implemented, following international recommendations3–5 and ensuring conceptual equivalence with the original version which had been designed in another language. Maximum rigour was employed for five questionnaires.16,17,19,21,22 The psychometric properties analysed were acceptable and were generally similar to those of the original version and to that of other versions of the scale adapted into other languages. None of the studies assessed all possible psychometric properties but reliability and validity were analysed in all of the questionnaires in different ways.

During the last few decades numerous scales for hip disabilities24–36 have been developed. It is preferable to adapt an already existing questionnaire than create a new one, always checking that the new version maintains the psychometric properties of the original. Adaptation is a more economical process and the use of the same questionnaire makes it easier to make comparisons between different populations. The seven questionnaires adapted into Spanish could easily be used in Latin American countries. However, in some cases it would be necessary to make a few minor changes to some of the words used to adapt them to local parlance in some countries. The same applies to the adapted in Mexico17 for its use in Spain or other Latin American AMICAL questionnaire countries. The fact that in the majority of studies the participants were predominantly female,15,17–20 except in three, does not appear to be an impediment for the questionnaires being used on males.

The eight questionnaires adapted into Spanish have different traits and the choice of one or the other would vary depending on needs and context, which could be either clinical and/or research. To select which questionnaire to use both methodological criteria (psychometric properties) and different practical aspects would need to be considered, such as the time needed to complete the questionnaires and give scores and their usefulness for certain disabilities and/or certain patient groups.

Of the eight questionnaires identified in the review there were three for any lower limb disabilities (LLFI, LEFS y AMICAL),15–17 another three for knee and/or hip disabilities (WOMAC, OAKHQOL y HKQ)18–20 and two exclusively for hip disabilities (HOS y iHOT-33).21,22 The most common used on an international scale are LEFS and WOMAC.

The LEFS questionnaire contains 20 questions. Unlike the WOMAC, discrimination may be made between pain and physical function. It is completed in 2min and scored in 2s. The LLFI questionnaire, containing 25 items has not yet been used much as it is of very recent creation. The AMICAL questionnaire is the only one to specifically assess the patient's quality of life with lower limb arthrosis. Its drawback is that it contains 43 questions and the patient takes around 15min to complete it.

The WOMAC questionnaire is the one most used internationally to assess the functional capacity of patients with knee and/or hip arthrosis and to assess the efficacy of the results of conservative and surgical treatments. It contains 24 items and the patient takes around 5–10min to complete it. Two shorter versions have been made, with just 11 and 14 questions, aimed at obtaining the same information as the original questionnaire but with a shorter administration time. We verified that both versions in Spanish maintained the same psychometric properties as the 24 item version.37–39 These new versions could be used in clinical practice and in research. With regard to negative aspects, the WOMAC scale does not assess aspects relating to quality of life and does not enable any discrimination between which joint is responsible in the case of hip and knee being simultaneously compromised. Scores may be changed by the presence of back pain, alterations in mood and other extra-articular disabilities.40 The OAKHQOL questionnaire is very complete since it includes aspects relating to mental health, social support, personal relations, sexual activity and professional life. The high number of items they contain hinders their use in clinical practice. The HKQ questionnaire consists of 16 questions. Its validation into Spanish was made only in knee arthroplasties, without including patients with hip disabilities. This could be a drawback when applying it to this patient type.

The classic questionnaires designed to assess outcome in older patients with hip arthrosis are less useful in young and active patients with non-arthritic conditions and with greater functional demands. Two adapted questionnaires are available for these patients. The HOS questionnaire contains 28 items and specifically assesses functional aspects. In a recent meta-analysis34 its use was recommended to assess the outcome after hip arthroscopy. The iHOT-33 questionnaire, unlike the HOS questionnaire, assesses emotional, social, employment and lifestyle aspects. There is a shorter version of 12 questions (iHOT-12)41 which could be more viable in clinical practice although it has not yet been validated into Spanish.

The review is particularly relevant because six of the eight adaptations were published during the last two years. As strengths of our review we may highlight, firstly, that both the rigour of the adaptation process of the questionnaire into Spanish and the psychometric properties analysed were examined by two authors. Moreover, the search process was exhaustive, and it is therefore improbable that other published scales adapted into Spanish could be found. Although we selected the most used data bases, it is possible that some studies were not detected since some journals cannot be indexed in these data bases.

To conclude, there are eight available scales for measuring the functional limitation of the hip which were adapted into Spanish, following international recommendations (five with maximum rigour). All had acceptable psychometric properties. Most adaptations (6 out of the 8) had been published in the last two years (from 2014). Several had been designed for the older adult population and others for typical problems seen in younger patients (mainly femoroacetabular impingement). Several specifically focused on functional assessment (shorter and simpler, but valid for standard clinical practice), whilst others covered multiple aspects (emotional, social, employment, etc.), which made them particularly suitable for evaluating complex cases or those with research objectives.

The authors have no conflict of interests to declare.