(iHOT-33) International Hip Outcome Tool

Clinician and patient looking at an ipad

International Hip Outcome Tool (iHOT-33)

Patient-reported outcome (PRO) tools are quickly becoming the preferred method of assessing patient outcomes following surgery or treatment intervention for an affected joint. Hip-specific PROs have been especially valuable in this regard but it has been noted that many of the existing hip pathology questionnaires are designed for patients with either hip fractures or those undergoing total hip arthroplasty. Unfortunately, many of these tools suffer from a ceiling effect which limits their usefulness in a young, physically active population.

In 2012 the International Hip Outcome Tool (iHOT-33) was developed to help address this issue. The iHOT-33 is a PRO tool that was designed for use in younger active patients that present with a variety of hip pathologies including avascular necrosis or osteochondral fracture, arthritis, ligamentous injury, and impingement, or other conditions that require hip arthroscopy [1].

The iHOT-33 is a 33-item survey with questions relating to Symptoms and Functional Limitations, Sports and Recreational Activities, Job-Related Concerns, and Lifestyle Concerns. It uses a visual analog scale with the verbal anchors “no problems at all” on the far right and “significantly impaired” on the left. The total score is calculated as a simple mean of the responses ranging from 0 to 100, with 100 representing the best possible quality-of-life score. Development of the iHOT followed a rigorous methodology that involved a large number of patients and results show that it is a valid, reliable, and highly responsive tool [2].

A shorter version of the International Hip Outcome Tool has also been developed, the iHOT-12. It has similar characteristics to the original iHOT-33 questionnaire and is also valid, reliable, and responsive to change [3]. Due to its brevity, the iHOT-12 is more appropriate for use in a clinical setting for initial assessments and post-operative follow-up [1].


The International Hip Outcome Tool has been validated for use in hip arthroscopy and is particularly useful in a younger, more active patient population (ages 18-60). A recent systematic evaluation of the psychometric properties of other outcome measures such as the Modified Harris Hip Score (MHHS), the Hip Outcome and Disability Survey (HOOS) and the Hip Outcome Score (HOS) revealed these tools to suffer from ceiling effects and decreased responsiveness that the iHOT-33 did not have [4].

Given its properties of validity, reliability, and responsiveness, the iHOT-33 has also been recommended for use as the primary outcome measure in prospective patient evaluations and randomized clinical trials [2].


The iHOT-33 has been criticized for the use of a composite scoring system in its survey. Using a single aggregate score instead of adopting subscales limits the tool’s ability to discriminate between important functional domains and also makes it difficult for clinicians to quickly pinpoint what specific areas patients are scoring poorly in.

Because the iHOT-33 is still a relatively new PRO tool, much work still needs to be done to evaluate it against other outcome scores but overall the iHOT appears to be a great tool to consider (particularly in a younger population) when assessing outcomes and a patient’s return to an active lifestyle post arthroscopy.


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  1. Physiopedia. International Hip Outcome Tool (iHOT). https://www.physio-pedia.com/International_Hip_Outcome_Tool_(iHOT)
  2. Mohtadi, N. G., Griffin, D. R., Pedersen, M. E., Chan, D., Safran, M. R., Parsons, N., … & McCarthy, J. C. (2012). The development and validation of a self-administered quality-of-life outcome measure for young, active patients with symptomatic hip disease: the International Hip Outcome Tool (iHOT-33). Arthroscopy: The Journal of Arthroscopic & Related Surgery, 28(5), 595-610. https://pubmed.ncbi.nlm.nih.gov/22542433/
  3. Griffin, D. R., Parsons, N., Mohtadi, N. G., Safran, M. R., & Multicenter Arthroscopy of the Hip Outcomes Research Network. (2012). A short version of the International Hip Outcome Tool (iHOT-12) for use in routine clinical practice. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 28(5), 611-618.https://pubmed.ncbi.nlm.nih.gov/22542434/
  4. Dwyer, M. K., Green, M., & McCarthy, J. C. (2015). Assessing outcomes following arthroscopic labral debridement—what can the IHOT-33 reveal?. Journal of Hip Preservation Surgery, 2(2), 152-157. https://academic.oup.com/jhps/article/2/2/152/2188809

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