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OrthoMeasure

Patient-reported outcome measure

HOOS Calculator

Hip disability and Osteoarthritis Outcome Score

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).

Free to use40 items~10 min0–100, higher is better

Symptoms

These questions should be answered thinking of your hip symptoms during the last week.

1Do you feel grinding, hear clicking or any other type of noise from your hip?
2Difficulties spreading legs wide apart
3Difficulties to stride out when walking
4How severe is your hip joint stiffness after first wakening in the morning?
5How severe is your hip stiffness after sitting, lying or resting later in the day?

Pain

What amount of hip pain have you experienced the last week during the following activities?

6How often do you experience hip pain?
7Straightening hip fully
8Bending hip fully
9Walking on a flat surface
10Going up or down stairs
11At night while in bed
12Sitting or lying
13Standing upright
14Walking on a hard surface (asphalt, concrete, etc.)
15Walking on an uneven surface

Function, daily living

The following questions concern your physical function. By this we mean your ability to move around and to look after yourself. For each of the following activities please indicate the degree of difficulty you have experienced in the last week due to your hip.

16Descending stairs
17Ascending stairs
18Rising from sitting
19Standing
20Bending to floor/pick up an object
21Walking on a flat surface
22Getting in/out of car
23Going shopping
24Putting on socks/stockings
25Rising from bed
26Taking off socks/stockings
27Lying in bed (turning over, maintaining hip position)
28Getting in/out of bath
29Sitting
30Getting on/off toilet
31Heavy domestic duties (push mowing, cleaning floors, etc.)
32Light domestic duties (cooking, dusting, etc.)

Function, sports and recreational activities

The following questions concern your physical function when being active on a higher level. Please answer each question indicating the degree of difficulty you have experienced in the last week due to your hip.

33Squatting
34Running
35Twisting/pivoting on loaded leg
36Walking on uneven surface

Quality of Life

37How often are you aware of your hip problem?
38Have you modified your life style to avoid potentially damaging activities to your hip?
39How much are you troubled with lack of confidence in your hip?
40In general, how much difficulty do you have with your hip?

What the HOOS score means

HOOS scores run from 0 to 100, where a higher score is better. The bands below are conventional reporting categories, not diagnostic cut-offs.

  • Extreme problems0–24
  • Severe problems25–49
  • Moderate problems50–74
  • Mild problems75–89
  • No to minimal problems90–100

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.

TypeValueSubscalePopulationFollow-upSource
MCID10 pointsAll subscalesTotal hip arthroplasty6–12 monthsNilsdotter AK 2003
MCID~9 pointsPainHip osteoarthritis, non-surgical—Nilsdotter A 2011
PASS~73 pointsPainHip arthroscopy for FAI12 monthsNwachukwu BU 2017
MDC10–16 pointsVaries by subscaleHip osteoarthritis—Nilsdotter A 2011

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 a higher raw score means worse symptoms. For each of the five subscales the mean of that subscale’s item scores is calculated, then transformed to a 0–100 scale with the formula: score = 100 − (mean item score × 100 ÷ 4). A score of 100 indicates no problems and 0 indicates extreme problems. The five subscale scores are reported separately and are not averaged into a single total.

Missing data

If no more than two items in a subscale are missing, the mean of the observed items in that subscale is substituted for the missing values. If more than two items in a subscale are missing, that subscale score is not calculated; the remaining subscales stay valid and are still reported.

Instrument profile

Developer
Ewa M. Roos, Lars S. Lohmander and colleagues
Institution
Lund University, Sweden
First published
2003
Custodian
koos.nu
Items
40
Response format
5-point Likert, scored 0–4
Score range
0 to 100
Direction
Higher score = better
Recall period
The last week
Completion time
About 10 minutes
Age range
Adults
Regions
Hip
Conditions
Hip osteoarthritis, Femoroacetabular impingement, Hip dysplasia, Hip pain
Procedures
Total hip arthroplasty, Hip arthroscopy, Periacetabular osteotomy
Languages
English, Swedish, Danish, Dutch, German, Spanish, 30+ validated translations
Test–retest (ICC)
0.78–0.93 across subscales
Internal consistency
Cronbach's alpha 0.82–0.98
Validity
Strong construct validity against the WOMAC, which is fully contained within the HOOS, and against the SF-36 physical subscales.
Responsiveness
Highly responsive after total hip arthroplasty. The Sport/Rec and QOL subscales are the most responsive in younger patients and in hip arthroscopy cohorts.
Ceiling effect
Ceiling effect in the ADL subscale after successful arthroplasty, where many patients score at or near 100.
Floor effect
Floor effects in Sport/Rec among older patients with advanced osteoarthritis who cannot attempt the activities at all.

Normative values

Reference values from published cohorts, for comparison against the score you calculated.

PopulationAgeMeanSD
Healthy reference, no hip complaints18–3495–100 across subscales—
Hip osteoarthritis, pre-arthroplasty—Pain 35–45, QOL 25–35—

When to use the HOOS

Well suited to

  • Hip osteoarthritis and total hip arthroplasty, before and after surgery.
  • Younger, active hip patients — femoroacetabular impingement, dysplasia, hip arthroscopy — where the Sport/Rec and QOL subscales capture change the WOMAC misses.
  • Any setting where pain, function and quality of life need to be distinguished from one another.

Limitations and poor fits

  • When a single registry-friendly summary figure is required — use the HOOS JR, which is validated as a single score, rather than averaging HOOS subscales.
  • When completion burden matters and only a global measure is needed — the HOOS-12 covers the same constructs in 12 items.
  • For non-arthritic groin and athletic hip pain, where the HAGOS was designed specifically for that population.

HOOS compared with other instruments

Instruments measuring a related construct, with the practical difference between them.

InstrumentItemsRangeWhat it adds
Harris Hip Score—0–100The Harris Hip Score is a 100-point clinician-administered hip assessment combining 44 points for pain, 47 for function, 4 for absence of deformity and 5 for range of motion, where 90 or above is graded excellent and below 70 poor.
HOS260–100The 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).
KOOS420–100The KOOS is a 42-item patient-reported questionnaire that scores knee function as five separate subscales — Symptoms, Pain, Activities of Daily Living, Sport and Recreation, and Quality of Life — each from 0 (extreme problems) to 100 (no problems).

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.

Free to useRights holder: Ewa M. Roos

The HOOS is distributed free of charge by its developer for clinical and research use, and the questionnaire and scoring instructions are published openly at koos.nu alongside the KOOS.

Rights holder’s own page

References

  1. Nilsdotter AK, Lohmander LS, Klässbo M, Roos EM. Hip disability and osteoarthritis outcome score (HOOS) — validity and responsiveness in total hip replacement. BMC Musculoskeletal Disorders. 2003.doi:10.1186/1471-2474-4-10PMID 12777182
  2. Nilsdotter A, Bremander A. Measures of hip function and symptoms. Arthritis Care & Research. 2011.doi:10.1002/acr.20549PMID 22588772
  3. Paradowski PT, Bergman S, Sundén-Lundius A, Lohmander LS, Roos EM. Knee complaints vary with age and gender in the adult population. BMC Musculoskeletal Disorders. 2006.doi:10.1186/1471-2474-7-38PMID 16670005
  4. Nwachukwu BU, Fields K, Chang B, Nawabi DH, Kelly BT, Ranawat AS. Preoperative outcome scores are predictive of achieving the minimal clinically important difference after arthroscopic treatment of femoroacetabular impingement. American Journal of Sports Medicine. 2017.PMID 28282508

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.