Translation and cross-cultural adaptation
Two well-qualified Slovenian translators, fluent in English language were responsible for the literary and conceptual translation of the HHS. First informed translator was a physiotherapist and the second one was a professional literary translator. Both translators’ mother tongue was Slovene and both were fluent in English. Both translations were compared and reviewed by a specially established group for this.
task consisting of one medical doctor who is specialist in physical medicine and rehabilitation; a two PhD. students of Biomedicine (Medical Faculty in Ljubljana) and one occupational therapist. The group highlighted any conceptual errors or inconsistencies in the translations in order to establish a single preliminary draft, synthesized from the separate forward translations. The backward translation of the HHS was carried out by a professional linguist with a university degree in English who had never seen the original English version of the questionnaire. At the end, all corrections were collected and a single affordable translation was created.
Six patients with diagnosis of coxarthrosis (N = 3) and hip fracture (N = 3) have tested the pre-final version to ensure understanding the purpose and meaning of each question to provide the final Slovenian version of the HHS. Patients expressed their opinions on used wording, understandability, interpretation, and cultural relevance of the translation. The final version of the Slovenian version of the HHS was approved after the final review.
Participants
Patients were regular residents of the nursing home “Lucija” in Portorož where study was performed. The inclusion criteria for the patients were: Coxarthrosis, Femoral fracture, Hip arthroplasty, Osteoporosis, Avascular necrosis, Hip pain, Congenital dislocation of hip, Hip effusion, Muscle tear, Edema of femoral head, Acetabular cystic lesion. All participants who passed eligibility criteria were asked to read and sign an informed consent form that had been approved by the Slovenian National Medical Ethics Committee (0120–46/2019/19).
Out of 180 elderly patients with different hip pathologies (Coxarthrosis, Femoral fracture, Hip arthroplasty, Osteoporosis, Hip pain) were initially considered for inclusion, 85 were eligible to enter the study, while 31 did not meet inclusion criteria. Amid eligible patients 12 refused to participate in the study. Participants were excluded from the study due to the inability to: to cooperate, understand and fulfill the questionnaires, understand the Slovenian language, have other inabilities to participate in the study (i.e., medical conditions, being alcohol or substance dependent, or current alcohol or substance abuse, cardiac or other medical instability, immobilized, fractured, having active malignancy, and mental illness). Finally, 42 elderly patients with different hip pathologies were enrolled into the study.
Minimal sample size (SS
min) was calculated via free G*Power 3.1.9.4 software (Faul, Kiel, Germany). G*Power is a tool to compute statistical power analyses for many different t tests, F tests, χ
2 tests, z tests and some exact tests. G*Power can also be used to compute effect sizes and to display graphically the results of power analyses [
22]. A priori correlation power analysis and sample size calculations were performed by assuming the population correlation alternative hypothesis—(pH
1 = 0.70) and determining the population correlation assuming null hypothesis—(pH
0 = 0.70). Furthermore, calculated effect size was 0.5, α error probability was 0.05 and power (1-β err prob) was 0.95. Minimal sample size required for validation was 42.
The authors determined and chose the Western Ontario and McMaster Universities Arthritis Index (WOMAC), the Short form-36 Health survey (SF-36) and Visual Analogue Scale (VAS) to be compared to the HHS. We specifically determined: the reliability, the responsiveness, the validity by correlation with the WOMAC [
23], the Short form-36 Health survey [
24] and VAS [
25], which are culturally adapted and validated on Slovenian language. The patients were asked to complete the Slovenian version of the HHS, the WOMAC, the SF-36 and VAS. Ten days after first assessment, patients were asked again to complete Slovenian version of HHS to determine the test–retest reliability. One physiotherapist and one occupational therapist provided assistance in reading, writing, and explanation, if requested. The study was performed between September 2019 and March 2020.
The HHS is a clinician-based, joint-specific assessment tool and requires the health-care professional to grade the patient’s pain (44 points), mobility and walking (47 points), range of motion (5 points), and absence of deformities (4 points). Each question is answered using a Likert scale with an overall score ranging from 0 (extreme symptoms) to 100 (no symptoms). A total HHS of ˂70 points is considered poor result, 70 to 80 is fair, 80 to 90 is good, and the 90 to 100 is excellent [
26].
The WOMAC is a self-administered, disease-specific measure that contains subscales for pain, stiffness, and physical function [
27]. The original global score is calculated as the sum of the scores for each subscale. Scores range from 0 to 20 (pain), 0 to 8 (stiffness), and 0 to 68 (function) [
27]. The higher the score, the worse the health state.
The SF-36 comprises eight scaled scores; each scale is directly transformed into a scale from 0 to 100 to identify the patient’s physical and mental state [
28]. These eight sections are: physical functioning (PF); role limitations due to physical function (RP); bodily pain (BP); general health perceptions (GH); vitality (VH); social function (SF); emotional function (RE); and mental health (MH) [
28,
29].