Validation of the Dutch version of the Hip Outcome Score

Patient Reported Outcome Measures (PROMs) are increasingly being used to
evaluate clinical outcome in orthopedics. However, most orthopedic assessment
tools are predominantly developed for elderly patients. Since the early 1990s
femoroacetabular impingement (FAI) and labral tears are recognized as a cause
of groin pain in young active adults. FAI, first described by Ganz, is a
morphological abnormality of the acetabulum (pincer FAI), the femoral head and
neck (cam FAI), or a combination of these two deformities. Over the last
decade, hip arthroscopy has become a popular procedure for the treatment of FAI
and labral tears. These young and active patients are limited at a high level
of activity. To measure outcome and results of arthroscopic surgery for FAI,
questionnaires should be focused on activities of these patients, in daily life
and during sports. Therefore, these patients require other PROMs than those
developed for patients with osteoarthritis for the outcome assessment of hip
arthroscopy. The Hip Outcome Score (HOS) is an example of a questionnaire
focused on activities and sports and is considered a valid tool for measuring
function in individuals who have undergone hip arthroscopy. The HOS was
developed for patients between the ages of 13 and 66 years. Items were
generated by physicians and physical therapists and reduced by factor analyses.
The HOS consists of two domains, a domain containing questions about activities
of daily living (ADL), containing 19 questions and the sports domain,
containing 9 questions. Three further questions are not utilized towards final
score. The questions are rated on a Likert scale from 0 to 4. There is an
additional *not applicable* (N/A) box for patients to tick when their
activities are limited by causes other than the hip. The potential top score is
68 for ADL and 36 for sports. The scores are divided by highest potential score
and multiplied by 100 to achieve a percentage score in each subscale. 100% is
the maximum score in both domains.
Martin and Philippon provided evidence of validity for the HOS as an outcome
instrument in hip arthroscopy in 2006. Tijssen recommends the HOS for
evaluating patient after hip arthroscopy for FAI in a review in 2011. Many
authors have used the HOS to describe post-operative results after hip
arthroscopy for FAI. The HOS scored best on agreement, internal consistency,
test re-test reliability, constructs validity, interpretability and measurement
error.

Despite its wide use in the international literature, the Hip Outcome Score is
not translated into the Dutch language nor is it validated for the Dutch
language.

The objective of this study is to evaluate the internal consistency,
reliability, constructs validity and floor and ceiling effects of the Dutch
version of the HOS questionnaire in patients with FAI and/or labral tears.
Moreover, the minimal clinical important difference (MCID) after 6 months in
the Dutch population will be determined.

First, we will conduct a forward/backward translation in accordance with
guidelines on cross-cultural adaptations (Guillemin et al.). The final version
will be made by the research team and will be tested on 20 patients.
Next, at three different time points, multiple questionnaires will be
administered to the study sample:
- Translated HOS
- HAGOS (Hip and Groin Outcome Score)
- mHHS (modified Harris Hip Score)
- iHOT-12
- NRS for pain
The second administration will be doen 7 days after the first administration,
both preoperatively. The third administration will be six months after surgery.

Patients will complete five questionnaires at three timepoints: two
preoperative administrations and on postoperative administration. There are no
risks related to participation in this study.