Osteoarthritis is a common condition of the hip that affects millions of adults around the world. It’s a frequent cause of pain, functional disability and reduced quality of life. The Hip Disability and Osteoarthritis Outcome Score (HOOS) is a patient-reported outcome tool (PRO tool) that is used to evaluate patients following Total hip arthroplasty (THA).

The HOOS questionnaire was built upon the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) – an instrument that also measures outcomes in osteoarthritis and following THA. Questions from the WOMAC (LK version 3.0) were used as the basis for the HOOS survey and two additional dimensions were added: sport & recreation and hip-related quality of life [1].

To its advantage, however, HOOS has been found to be more responsive than the WOMAC survey [1].

In order to assess patient outcomes, HOOS is composed of 40 questions and looks at five subscales: Pain (10 items), symptoms (5 items), activity of daily living (17 items), sport and recreation function (4 items) and hip related quality of life (4 items). A total HOOS score is calculated by using a simple formula to produce a score that ranges from 0-100 with higher scores representing better function.

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The HOOS survey is easy to administer and relatively easy to score. The questionnaire is self-explanatory, user-friendly and well-represented in literature. Additionally, because HOOS contains questions from the WOMAC, WOMAC scores may be calculated from a HOOS questionnaire. Interestingly enough, HOOS is said to be more valuable for more active and younger patients than the WOMAC. This is because of HOOS’ added subscales.

Another advantage of HOOS is that it may be used over short and long term intervals to assess changes induced by treatment (ie. medication, physical therapy, operation), primary injuries or post-traumatic osteoarthritis [2].



HOOS takes approximately 10-15 minutes to complete, which some patients may find difficult. Overall, HOOS is a well-regarded tool for the evaluation of patients following a THA. If the time required to complete the survey isn’t an issue, it’s a solid PRO tool to consider.



No license is required to use the HOOS survey. It may be obtained freely from http://www.koos.nu/


About CODE Technology

CODE Technology is a PRO vendor singularly focused on collecting, reporting, and benchmarking PRO data as a service. Our real life humans – not robots – will administer surveys and handle all data collection, 100% outside of the office, you won’t even know we’re there. Better yet, with CODE as your outcomes vendor, additional employees to help with all the data won’t be necessary. Just ask our client, Joe Holmbo, Clinical Director for ORA Orthopedics. “For us to be able to collect PROs without adding any additional staff, it’s well worth the investment that we’ve made with CODE.”

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  1. Nilsdotter, A. K., Lohmander, L. S., Klässbo, M., & Roos, E. M. (2003). Hip disability and osteoarthritis outcome score (HOOS) – validity and responsiveness in total hip replacement. BMC Musculoskeletal Disorders, 4, 10. http://doi.org/10.1186/1471-2474-4-10, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC161815/
  2. Physiopedia. Hip Disability and Osteoarthritis Outcome Score. http://www.physio-pedia.com/Hip_Disability_and_Osteoarthritis_Outcome_Score
  3. Nilsdotter, A., & Bremander, A. (2011). Measures of hip function and symptoms: Harris hip score (HHS), hip disability and osteoarthritis outcome score (HOOS), Oxford hip score (OHS), Lequesne index of severity for osteoarthritis of the hip (LISOH), and American Academy of Orthopedic Surgeons (AAOS) hip and knee questionnaire. Arthritis care & research, 63(S11), S200-S207. http://onlinelibrary.wiley.com/doi/10.1002/acr.20549/pdf