J. Phys. Ther. Sci. Vol. 26, No. 5, 2014746
exercise has a beneficial effect in patients with knee
osteo-arthritis.
SUBJECTS AND METHODS
SubjectsThe criteria for inclusion were as follows:
prediagnosed
case of knee OA as per the American College of Rheuma-tology
(ACR) and radiological evidence of primary osteo-arthritis of grade
3 or less on the Kellgren Lawrence scale; age between 4065 years,
unilateral or bilateral involve-ment (in the case of bilateral
involvement, the more symp-tomatic knee was included), and pain in
and around the knee. Subjects were excluded if they had any
deformity of the knee, hip or back, had any central or peripheral
nervous system involvement, had received steroids or
intra-articular injection within the previous three months, were
uncoop-erative patients, or received physiotherapy treatment in the
past 6 months. The study was approved by our Institutional Ethical
Committee (IEC), and written consent was obtained from all the
participants. All experiments were conducted according to the
Declaration of Helsinki. Patients who met the inclusion criteria
were randomly assigned to one of two groups (Fig. 1). Neither group
was aware of the treatment that the other group was receiving. All
measurements of de-pendent variables were obtained by another
therapist who was blinded to group assignment.
MethodsAll the subjects in the experimental group performed
isometric exercises including isometric quadriceps, straight leg
raising, and isometric hip adduction exercise. All the subjects
also received ultrasound therapy as per the pa-tients requirement
with 1.5 watts/cm2 for 7 minutes in con-tinuous mode at the tender
point around the knee joint prior to exercise.
The subjects in the experimental group performed the following
sets of exercise for 5 weeks (5 days/week). All exercises were
performed in sets of 10 repetitions; 1 set of all exercises was
performed twice a day for the 1st week, and this progressed to 2
sets twice a day until the 3rd week and then 3 sets twice a day
until the 5th week.
Isometric quadriceps exercise: Patients lay in a supine
position. A rolled up towel was put beneath the knee. They were
instructed to maximally activate their thigh muscles in order to
straighten their knee and hold the contraction for 5 seconds.
Straight leg raising (SLR) exercise: Patients lay in a su-pine
position. They were instructed to perform a maximum isometric
quadriceps contraction prior to the lifting phase of the exercise.
Then they were instructed to lift the leg up to 10 cm above the
plinth and hold the contraction during the lifting phase for 10
seconds.
Isometric hip adduction exercise: Patients lay in a supine
position. A small pillow was put between the knees. They were
instructed to perform isometric hip adduction exercise while
pressing the pillow between the knees and to main-tain the
adduction with contraction for 5 seconds.
The control group received ultrasound therapy as per the
patients requirement with an intensity of 1.5 watts/cm2 for 7
minutes in continuous mode at the tender point around the knee
joint. They were told to continue their normal daily activities,
and no extra exercises were applied.
The outcome measures or dependent variables selected for this
study were pain intensity, knee function, and iso-metric quadriceps
strength. These variables were measured using the Numerical Rating
Scale (NRS)14, 15), a reduced WOMAC index16, 17), and a strength
gauge device1821), re-spectively. All the measurements were taken
at baseline (week 0) and at the end of the trial at week 5.
Statistical analysis was performed using the SPSS 15.0 Software
(SPSS Inc., Chicago, IL, USA). A Shapiro-Wilk test was used to
assess whether the dependent variable con-formed to a normal
distribution and so that parametric test-ing could be undertaken.
The results of the Shapiro-Wilk tests suggested that the dependent
variable was not nor-mally distributed (p0.05).
On comparing the isometric quadriceps strength val-ues between
baseline and at the end of the 5th week, a sig-nificant improvement
was noted in the experimental group (p
J. Phys. Ther. Sci. Vol. 26, No. 5, 2014748
joints and minimize the effect of impact by spreading the forces
out over a greater area so it may be hypothesized that improvement
in muscle strength is one of the main causes of reduced pain and
disability. In the present study, the re-duction in pain and
disability in the experimental group may be attributed to increased
quadriceps muscle strength and thereby improved stability, which
leads to reduction of pain and disability.
Moreover, the subjects of both groups received ultra-sound
therapy (UST) with an intensity of 1.5 watts/cm2 for 7 minutes in
continuous mode at the tender point around the knee joint prior to
exercise. The reduction in soft tis-sue pain by UST could result
from increased blood flow to muscles in spasm or the rise in
temperature causing relax-ation of muscle guarding. In a review of
the effectiveness of UST in treating musculoskeletal conditions,
Falconer et al.30) found that most reports indicate that
therapeutic ultrasound appears to relieve OA pain. Further, Centin
N et al.31) concluded in their study that exercise and physical
agents can reduce pain and improve function and health status in
patients with knee OA. Since pain and disability are
interdependent, a reduction in one will cause a reduc-tion in the
other. All three exercises, isometric quadriceps exercise, straight
leg raising, and isometric hip adduction, were necessary for the
results of this study to happen. It is recommended to see which one
has more influence on the increase in muscle strength in a future
study. In conclusion, the 5-week of isometric quadriceps exercise
program for patients with knee OA showed beneficial effects on
quad-riceps muscle strength, pain, and functional disability, but
future parametric studies are needed with larger subject numbers to
confirm this finding.
ACKNOWLEDGEMENT
The authors extend their appreciation to the Deanship of
Scientific Research at King Saud University for funding this work
through research group project No. RGP-VPP-209.
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