Validity and reliability of the Marx
Activity Rating Scale in patients
from Mexico City.
Izaguirre A, Olivos A, Ibarra C, Marx R.
Background
• The number of outcome rating scales to
measure patient function related to knee
injury has increase in the past years.
• Lysholm and Knee injury and Osteoarthritis
Outcome Score (KOOS), are disease specific
questionnaires.
• When evaluating patients with knee diseases,
besides measuring functionality, the level of
activity is an important variable of interest.
Marx RG .Am J Sports Med 2001.
Background
• The Marx activity scale.
• This instrument is a patient reported
instrument, which is completed in
approximately 1 minute, which facilitates its
use with other instruments.
– Running
– Cutting
– Deccelerating
– Pivoting
Marx RG .Am J Sports Med 2001.
Purpose
• This useful instrument is not available for use
in Spanish.
• Therefore, the purpose of this study was to
perform a cross-cultural adaptation of the
Marx activity scale into Spanish, and to
evaluate validity, floor and ceiling effect, and
reliability of this version in Mexican patients
with knee injuries.
Methods
Cross-Cultural Translation.
• Two orthopedic surgeons from Mexico, independently translated
the Marx Activity Scale to Spanish.
• This provisional Spanish version was translated back to English by a
qualified translator (mother tongue Spanish and fluent in English)
and a clinical director (mother tongue English and fluent in
Spanish).
• This back translation was reviewed against the source by the
developers of Marx Activity Scale in order to check for
discrepancies.
• The final Spanish was tested on ten patients with knee injuries to
assess problems of comprehension of the questionnaire content.
Methods
Patients
• After approval of the Institutional Review Board, one-hundred
patients with knee injuries were enroled to this study.
• The sample ws recruited in the outpatient clinic of the Service of
Sports Orthopedic Surgery and Arthroscopy of the National
Rehabilitation Institute, of Mexico City, Mexico.
Inclusion criteria were:
1. Age between 18 to 50 years,
2. Any gender,
3. Diagnosis of ACL lesion,
4. Menisci lesion,
5. Chondral lesion,
6. Patellar dislocation,
osteoarthritis.
Exclusion criteria were:
1. Inflammatory arthritis
2. Inability of understand
3. Spanish written
language.
Methods
Patients
• Before patients were seen by their orthopedic
surgeons at consult,
– Lysholm
– Tegner
– KOOS
– International Knee Documentation Committee
Subjective scale
– Spanish version of the Marx Activity scale were
administered.
Methods
Scales:The Lysholm score
• First described in 1982.
• The score was designed to be physican
administered and measure outcomes after
knee ligament surgery .
• 8 items which include, limp, support, locking,
instability, pain, swelling, stair climbing and
squatting.
Lysholm 1982 Am J Sports Med 1982
Methods
Scales: The Tegner Activity Score
• 11 items with a a scoring range of 0-10; with
higher scores representing higher levels of
physical activity.
– 6-10 corresponds to participation in
competitive/or recreational sports,
– 1 to 5 corresponds to participation in recreational
sports and light to moderate heavy labors,
– and 0 is recorded for disability. (4)
Tegner Y, Lysholm J. Clin Orthop Relat Res 19859.
Methods
Scales: KOOS
• 42 item
• Disease-specific questionnaire:
– Pain (9 items)
– Symptoms (7 items)
– Activities of daily living (17 items)
– Sport and Recreation (5 items)
– Knee related Quality of Life (4 items). (7)
Roos EM, Toksvig-Larsen S. Health Qual Life Outcomes. 2003
Methods
Marx Activity Scale
• The Spanish version of Marx Activity Scale
consists of 4 items
• It relates to the frequency with which the
patient, runs, cuts, pivots and decelerates.
• Its score ranges from 0 to 16 with higher score
representing higher activity level.
Marx RG .Am J Sports Med 2001.
Reproducibility.
• 20 healthy individuals with 18 to 50 years of
age were submitted twice to the
questionnaire (2 weeks)
• For all the cases the activity level remained
constant while taking both questionnaires.
Construct Validity.
• Patients with high Spanish Marx Activity Scale
scores would score higher Tegner Values.
• Patients with high Spanish Marx Activity Scale
scores would score higher KOOS Sports and
recreation values.
• For divergent validity, the Spanish Marx
Activity Scale would correlate with patient age
inversely.
Statistical Analyses.
• The intraclass correlation coefficient (ICC) was
used to asses the instrument test-retest
reliability. (0.8 good reliability)
• Spearman’s coeffient for correlations.
– Strong correlation for values >0.5
– Moderate correlation for values between 0.31 and
0.5
– Weak correlations when < 0.31.
Results
Translation Process.
• During forward and backward translations, no
major modification were made by the
translators.
• In the pilot study no item was found to cause
confusion by the respondents.
Results
Demographics
• 100 patients for construct Validity.
• Mean age was 35.89 ± 12.4.
• 64 % were men compared to 36 women
– ACL lesion in 40 patients
– Meniscus lesion in 15 patients
– Osteoarthritis in 31 patients
– Patelofemoral disorders in 14 patients.
Results
Reproducibility
The intraclass correlation coefficient of the
Spanish version of the Marx Activity Scale
was of 0.8.
Spanish Version
of the Marx
Activity Scale
Test (n=20)
Retest (n=20)
ICC (95% CI)
5.8 ± 3.75
6.5± 3.2
0.80 (0.72-0.95)
Construct Validity
• Positive moderate
correlations
–
–
–
–
–
Marx
Activity
Scale
Moderate negative
correlation
– age.
KOOS pain
Symptoms
ADL
Lysholm
Tegner IKDC subjective
form.
KOOS
Pain
KOOS
Symptoms
0.357
p<0.001
0.359
p<0.001
KOOS
KOOS
KOOS
ADL Sport/Rec QoL
0.315
p<0.001
0.183
p=0.06
0.04
p=NS
Lysholm IKDC-S Tegner
0.312
0.002
0.295
p=0.003
0.344
p=0.001
Age
-0. 329
p=0.001
Discussion
• The Spanish version of the Marx Activity scale has appropriate
psychometric properties in terms of reliability, construct
validity and ceiling and floor effects.
• With regard to construct validity, the Marx Activity scale had
moderate correlation between KOOS in the subcales of pain,
symptoms, activities of daily living.
• Spanish version of the Marx Activity scale does not correlate
with the Sports and Recreation Subscale of KOOS.
Discussion
• Moderate positive correlation with the Tegner further
confirms construct validity.
• This spanish version had a floor effect of 29%, close to the
33% margin set beforehand. Patients were studied
preoperatively
Gracias