Patient-reported outcome measure
HOS Calculator
Hip Outcome Score
The Hip Outcome Score is a 28-item patient-reported questionnaire for non-arthritic hip conditions that yields two independent percentage scores — an Activities of Daily Living subscale, administered as 19 questions of which 17 are scored, and a 9-item Sports subscale — each running from 0% (unable to perform the listed activities) to 100% (no difficulty at all).
What the HOS score means
HOS scores run from 0 to 100, where a higher score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.
- Severe limitation0–24.9
Descriptive stratum only. Most listed activities are performed with extreme difficulty or not at all.
- Marked limitation25–49.9
Descriptive stratum only.
- Moderate limitation50–74.9
Descriptive stratum only.
- Mild limitation75–89.9
Descriptive stratum only. Note that the published patient acceptable symptom state for the ADL subscale after arthroscopic surgery for femoroacetabular impingement sits inside this band, at roughly 87%.
- Minimal to no limitation90–100
Descriptive stratum only.
Clinically important thresholds
A change in score only matters if it exceeds the smallest difference patients actually notice. Every threshold below is reported with the population it was derived in — a threshold quoted without its population is not usable.
| Type | Value | Subscale | Population | Follow-up | Source |
|---|---|---|---|---|---|
| PASS | ≈ 87% | Activities of Daily Living | Arthroscopic surgery for femoroacetabular impingement | 12 months | Chahal J 2015 |
| PASS | ≈ 75% | Sports | Arthroscopic surgery for femoroacetabular impingement | 12 months | Chahal J 2015 |
MCID is the smallest change a patient perceives as meaningful. PASS is the score above which patients consider their state acceptable. SCB is a substantial rather than minimal benefit. MDC is the smallest change exceeding measurement error.
How the score is calculated
Stated in full so the calculation can be independently checked, and reproduced by hand if needed.
Each item is scored 0 to 4, where 4 is "No difficulty at all" and 0 is "Unable to do", so a higher raw score means better function. Items marked N/A are removed from both the numerator and the denominator. Each subscale is then calculated separately as: subscale score = (sum of the item scores that were answered ÷ (4 × the number of items answered)) × 100, reported as a percentage to one decimal place. The Activities of Daily Living subscale is administered as 19 questions but scored on 17 of them — putting on socks and shoes, and sitting for 15 minutes, are asked but do not enter the calculation, so the maximum attainable raw score is 68 rather than 76. The Sports subscale is scored on all 9 of its items, for a maximum of 36. The two subscales are never combined into a single figure; the headline percentage reported here is the ADL subscale, with the Sports subscale given alongside it. The severity bands shown on this page are descriptive strata for orientation — the original publications do not define severity categories, and the published patient acceptable symptom state values in the thresholds section are what should be used to judge whether a result is acceptable to the patient.
Missing data
The instrument's own rule is that an activity limited by something other than the hip is marked N/A and excluded from both the numerator and the denominator, so the maximum attainable score falls with the number of items used. The published completion rule is that at least 14 of the 17 scored Activities of Daily Living items and at least 7 of the 9 Sports items must have a response; below that the subscale is not calculated here, and the result says which subscale was withheld and why. The number of items actually used is reported alongside each percentage. Because a blank raises rather than lowers the score, a subscale computed from the minimum number of items should be read with caution and the item count recorded with the result. In a patient who does not play sport the Sports subscale should not be administered at all rather than scored from the two or three items they attempt.
Instrument profile
- Developer
- RobRoy L. Martin and colleagues
- Institution
- Duquesne University, Pittsburgh
- First published
- 2006
- Items
- 26
- Response format
- 5-point difficulty scale scored 0–4, plus an N/A option on every item. 26 of the 28 administered items are scored: 17 of the 19 activities-of-daily-living questions and all 9 sports questions
- Score range
- 0 to 100
- Direction
- Higher score = better
- Recall period
- Current function — respondents rate the difficulty they have with each activity as things stand now
- Completion time
- About 5 minutes
- Age range
- Adults and adolescents; developed and validated in an active, largely non-arthritic population
- Regions
- Hip
- Conditions
- Femoroacetabular impingement, Acetabular labral tear, Hip instability, Chondral injury of the hip, Hip osteoarthritis, Groin pain
- Procedures
- Hip arthroscopy, Labral repair, Femoroplasty, Acetabuloplasty, Periacetabular osteotomy
- Languages
- English (original), Dutch, Danish, Brazilian Portuguese, Turkish, Persian, Chinese, German
- Test–retest (ICC)
- Approximately 0.98 for the Activities of Daily Living subscale and 0.92 for the Sports subscale in the developmental work.
- Internal consistency
- Cronbach's alpha above 0.90 for both subscales.
- Validity
- Construct validity supported against the SF-36 physical function subscale and global rating of hip function; the Sports subscale discriminates activity level where the ADL subscale does not.
- Responsiveness
- Responsive to hip arthroscopy, with the Sports subscale changing more than the ADL subscale in active patients. Published minimal clinically important difference and minimal detectable change estimates vary substantially between cohorts and follow-up intervals, so a threshold should be taken from a population matched to the patient rather than applied generically.
- Ceiling effect
- Pronounced ceiling effect on the Activities of Daily Living subscale in young, athletic patients, many of whom report 100% before surgery. The Sports subscale is the discriminating half of the instrument in that group.
- Floor effect
- Floor effects on the Sports subscale among older or sedentary patients, who cannot attempt several of the nine activities at all — in whom the subscale should usually not be administered.
Normative values
Reference values from published cohorts, for comparison against the score you calculated.
| Population | Age | Mean | SD |
|---|---|---|---|
| Pre-operative hip arthroscopy for femoroacetabular impingement or labral tear (typical cohort values, not reference norms) | — | ADL approximately 60–70%, Sports approximately 40–50% | — |
| One to two years after hip arthroscopy (typical cohort values, not reference norms) | — | ADL approximately 85–92%, Sports approximately 75–85% | — |
| Asymptomatic young adults | — | At or close to 100% on both subscales | — |
When to use the HOS
Well suited to
- Non-arthritic hip pathology in active patients — femoroacetabular impingement, labral tears, chondral injury and hip instability — which is the population the instrument was built for.
- Before and after hip arthroscopy, where the Sports subscale captures return-to-sport limitation that the ADL subscale and general hip scores miss entirely.
- Where a short, self-administered measure is needed and the two domains must be reported separately rather than merged.
Limitations and poor fits
- Advanced hip osteoarthritis and hip arthroplasty populations, for which the HOOS, WOMAC or Oxford Hip Score were designed and have better measurement properties.
- In patients who do not participate in sport — the Sports subscale will floor or be largely N/A, and only the ADL subscale should be reported.
- Where a single summary figure is required, because the two subscales must not be averaged.
- For groin pain of predominantly adductor, iliopsoas or inguinal origin, where the HAGOS covers the relevant constructs more completely.
HOS compared with other instruments
Instruments measuring a related construct, with the practical difference between them.
| Instrument | Items | Range | What it adds |
|---|---|---|---|
| HOOS | 40 | 0–100 | The HOOS is a 40-item patient-reported questionnaire that scores hip function as five separate subscales — Symptoms, Pain, Activities of Daily Living, Sport and Recreation, and Hip-related Quality of Life — each from 0 (extreme problems) to 100 (no problems). |
| Oxford Hip Score | 12 | 0–48 | The Oxford Hip Score is a 12-item patient-reported questionnaire about hip pain and everyday function over the past four weeks, each item scored 0 to 4 and summed to a total of 0 to 48 in which 48 represents the best possible hip — it is licensed by Oxford University Innovation, so the item wording is not reproduced here. |
Copyright and permitted use
Published openly because it is the question every clinician and researcher asks before using an instrument, and almost nobody answers it.
The Hip Outcome Score was published in full in the peer-reviewed literature and is distributed without charge by hospitals, professional bodies and translation groups, which is the basis on which it is reproduced here. We have no written confirmation from the developer, and no commercial licensing programme is known to us — that is an absence of evidence rather than confirmation, so treat the status as free but unconfirmed.
References
- Martin RL, Kelly BT, Philippon MJ. Evidence of validity for the Hip Outcome Score. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2006.
- Martin RL, Philippon MJ. Evidence of validity for the Hip Outcome Score in hip arthroscopy. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2007.
- Martin RL, Philippon MJ. Evidence of reliability and responsiveness for the Hip Outcome Score. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2008.
- Chahal J, Van Thiel GS, Mather RC 3rd, et al.. The patient acceptable symptomatic state for the modified Harris Hip Score and Hip Outcome Score among patients undergoing surgical treatment for femoroacetabular impingement. American Journal of Sports Medicine. 2015.
- Thorborg K, Tijssen M, Habets B, et al.. Patient-reported outcome (PRO) questionnaires for young to middle-aged adults with hip and groin disability: a systematic review of the clinimetric evidence. British Journal of Sports Medicine. 2015.
Editorial status
Not yet reviewedQueued for clinical review by Sam Tuffun, PT, DPT. Sign-off has not taken place — this is a placeholder assignment, not a completed review.