leptin formation. Leptin reaches the brain and enters
saturated transportation in the hypothalamus from
fat storage (Diamond and Eichler, 2002). When
hungry adipose tissue secretes leptin, CNS
stimulation, cold exposure, and exercise. Obesity,
glucocorticoids, glucose, and insulin can inhibit the
secretion of leptin from adipose tissue. When leptin
reaches the hypothalamus, NPY secretion is
inhibited, which normally reduces energy
expenditure, stimulates synthesis, stores fat, and
increases appetite. Adiponectin sensitizes tissues for
the effects of insulin. Obesity and insulin resistance
negatively regulate adiponectin secretion from
adipose tissue, where weight loss increases secretion
(Diamond and Eichler, 2002).
Body mass index, formerly called the Quetelet
index, is a measure to indicate nutritional status in
adults. BMI measured by weight in kilograms (kg)
divided by height in meters squared (kg / m2) (CDC
USA, 2009). In Asians, the limit of overweight is
23.0 kg / m2 which is lower than WHO criteria. The
suggested classification for Asians while still needs
to be revised because of further validation and
clinical symptoms. Some research that supports this
limit comes from Chinese living in Hong Kong (ko
et al 1999) where the risk of morbidity increases
with a BMI> 23.0 kg / m2.
Osteoarthritis (OA) is a disease caused by
mechanical and biological disorders that damage the
stability of the normal series of degradation and
synthesis of joint cartilage chondrocytes,
extracellular matrix, and subchondral bone. This can
occur due to various factors including genetic,
developmental, metabolic and trauma factors. OA
involves various tissues in the arthritic joints. OA
manifestations include morphological, biochemical,
molecular and biochemical changes in both cellular
and bone matrix that cause softening, fibrillation,
ulceration, loss of joint cartilage, sclerosis and
subchondral bone eburnation, osteophytes and
subchondral cysts. Clinically the symptoms that
appear in patients with OA are joint pain and
stiffness, limited mobility, crepitation, effusion,
various signs of inflammation without accompanied
by systemic effects (Sharma L, 2007).
Obesity is a risk factor for the development of
osteoarthritis. The association of height weight with
the incidence of OA is still said to be uncertain but
may involve cartilage degeneration due to overload.
Another mechanical factor is knee alignment. In
patients with knee varus, BMI appears to be related
to the severity of OA, especially medial tibiofemoral
OA.
A very important factor in the pathomechanics of
OA genu is the high and repeated burden on the
knee joint during walking and activity. During
walking, the load that passes through the knee joint
is not transmitted equally between the medial and
lateral compartments. The load on the medial
compartment is about 2.5 times greater than the load
on the lateral compartment. This is the reason for the
high prevalence of OA genu media compartments
(75% of all cases) rather than lateral compartments
(Enohumah KO and Imarengiaye CO, 2008).
Also, there are changes in the synovial
membrane and synovial fluid. Mild to moderate
inflammatory reactions occur in the synovial
membrane that contains cartilage articular
fragments. Whereas in the synovial fluid there is a
decrease in the concentration of molecular weight
and abnormal production of hyaluronate. Impaired
hyaluronate production and increased hyaluronate
breakdown which causes a decrease in hyaluronate
concentration. Changes in the synovial fluid also
result from an increase in water content and an
increase in pathological concentrations (Enohumah
KO and Imarengiaye CO, 2008).
Physical activity is defined as body movements
produced by skeletal muscles that require energy
expenditure. The most commonly used way to be
always active is by walking, cycling, recreation, and
sports that can be done at any level of skill and
pleasure (“WHO | Physical Activity,” 2019). MET is
a unit used to estimate the energy expended from
each activity (Miles, 2007). Understanding the level
of physical activity is the total energy needed (TEE)
or used in 24 hours divided by the basal metabolic
rate (BMR) for 24 hours.
The total energy needed in 24 hours can be
calculated based on the activities carried out in one
day and calculated the amount of energy needed for
these activities, then added up. The amount of
energy used can be seen based on the compendium
of physical activity. The purpose of this study is to
find whether there is a relationship between the level
of physical activity and body mass index in obese
patients with knee osteoarthritis. We hypothesize
that a decrease in physical activity caused by an
increase in BMI in patients with obesity and
osteoarthritis of the knee who seek treatment at the
obesity clinic.
2 METHODS
This study protocol was approved by the University
of Indonesia Ethics Committee and written consent