Hip disability and Osteoarthritis Outcome Score (HOOS) Scoring instructions, June 2013

1

HOOS Scoring 2013

A change in how to manage missing items was introduced in 2013. Previously, 2

missing items were allowed in each subscale. From 2013, at least 50% of the items

should be responded to. This change is reflected in the updated Excel scoring file

formulae available from www.koos.nu. The differences in subscale level are outlined

in the following table:

Number of items needed

for calculation of

subscale score (2013

rule for missing items)

Number of items needed

for calculation of

subscale score (2003 rule

for missing items)

Pain 5 8

Symptoms 3 3

ADL 9 15

Sport/Rec 2 2

QOL 2 2

HOOS Scoring Instructions

Assign the following scores to the boxes:

None Mild Moderate Severe Extreme

0 1 2 3 4

Each subscale score is calculated independently. Calculate the mean score of the

individual items of each subscale and divide by 4 (the highest possible score for a

single answer option). Traditionally in orthopedics, 100 indicate no problems and 0

indicates extreme problems. The normalized score is transformed to meet this

standard.

Missing data: If a mark is placed outside a box, the closest box is chosen. If two

boxes are marked, that which indicates the more severe problem is chosen.

As long as at least 50% of the subscale items are answered for each subscale, a

mean score can be calculated. If more than 50% of the subscale items are omitted,

the response is considered invalid and no subscale score should be calculated. For

the subscale Pain, this means that 5 items must be answered; for Symptoms, 3

items; for ADL, 9 items; for Sport/Rec, 2 items; and for QOL, 2 items must be

answered in order to calculate a subscale score. Subscale scores are independent

and can be reported for any number of the individual subscales, i.e. if a particular

subscale is not considered valid (for example, the subscale Sport/Rec 2 weeks after

total hip replacement), the results from the other subscale can be reported at this

time-point.

Hip disability and Osteoarthritis Outcome Score (HOOS) Scoring instructions, June 2013

2

HOOS Excel scoring files

Excel spreadsheets with formulae to calculate the five subscale scores are available

from www.koos.nu. If, for any reason, you prefer to use your own spreadsheets, the

Excel formulae are given below.

Excel formulation: When the raw data have been entered in the order the items

occur in the HOOS questionnaires available from www.koos.nu, these Excel

formulations can be copied and pasted directly into an English version of an Excel

spreadsheet to automatically calculate the five subscore scales. Please note that it

has been assumed that the items in the subscale symptoms appear first in the

questionnaire.

HOOS Pain: =100-AVERAGE(G2:P2)/4*100

HOOS Symptoms: =100-AVERAGE(B2:F2)/4*100

HOOS ADL: =100-AVERAGE(Q2:AG2)/4*100

HOOS Sport/Rec: =100-AVERAGE(AH2:AK2)/4*100

HOOS QOL: =100-AVERAGE(AL2:AO2)/4*100

HOOS Manual Score calculation

The slightly updated version of the formulae (used from June 2013 in the

spreadsheets available from www.koos.nu) does not need any manual imputation:

Apply the mean of the observed items within the subscale (e.g. HOOS Pain), divide

by 4, and multiply by 100; when this number is then subtracted from 100, you have

the HOOS subscale estimate for that particular cross-sectional assessment of the

individual patient. For manual calculations, please use the formulae provided below

for each subscale:

1. PAIN 100−

™?? ™??? ™ ? ™? × ™?

?

= 𝐻𝑂𝑂𝑆 𝑃𝑎𝑖𝑛

2. SYMPTOMS 100−

™?? ™?? ? ™ ? ™ × ™?

?

= 𝐻𝑂𝑂𝑆 𝑆𝑦𝑚𝑝𝑡𝑜𝑚𝑠

3. ADL 100−

™?? ™??? ™ ? ™? × ™?

?

= 𝐻𝑂𝑂𝑆 𝐴𝐷𝐿

4. SPORT/REC 100−

™?? ™??? ™? ? ™? × ™?

?

= 𝐻𝑂𝑂𝑆 𝑆𝑝𝑜𝑟𝑡/𝑅𝑒𝑐

5. QOL 100−

™?? ™??? ™ ? ™ × ™?

?

= 𝐾𝑂𝑂𝑆 𝑄𝑂𝐿

Hip disability and Osteoarthritis Outcome Score (HOOS) Scoring instructions, June 2013

3

WOMAC - How to score from the HOOS

Assign scores from 0 to 4 to the boxes as shown above. To get original WOMAC

Scores, sum the item scores for each subscale. If you prefer percentage scores

in accordance with the HOOS, use the formula provided below to convert the

original WOMAC scores.

Transformed scale = 100 - actual raw score x 100

Possible raw score range

WOMAC subscores Original score = sum

of the following items

Possible

raw score range

Pain P4-P8 20

Stiffness S4-S5 8

Function A1-A17 68

HOOS Profile

To visualize differences in the five different HOOS subscores and change between

different administrations of the HOOS (e.g. pre-treatment to post-treatment), HOOS

Profiles can be plotted, as illustrated below.

pain symptoms ADL sport/recr QOL

m

e

a

n

H

O

O

S

s

c

o

r

e

0

20

40

60

80

100

preop

postop