INDIVIDUAL ASSIGNMENT

Dermato Musculosceletal Module

2nd year / 3rd Semester / 2019 / FMUI 2018
Devi Nurhalizah Atjo
1806226954 – Group B

Knee Pain
Pathophysiology of Knee Pain

INTRODUCTION

Knee pain is a type of pain that may refer to joint pathology of knee,
ligamentous sprains or overuse injuries.[1] There are two types of knee pain which are
traumatic and non-traumatic. Traumatic knee pain is the one caused by injuries such
as meniscus, cruciate and fracture. While the non-traumatic knee pain consists of
mechanical and arthritis occurrence such as meniscus, osteoarthritis, joint mouse,
plica, cruciate, inflammatory joint disease, and infection. Among those kinds of knee
pain, osteoarthritis is considered as one of the most common knee pain that occurs
wordwidely.[2] Acute knee pain exists for more than 1 million emergency department
visits and over 1.9 million primary care outpatient visits hospital annually in the U.S
alone.[1]This means knee pain occurs very commonly in society and hence knowledge
and awareness regarding this illness should be elevated.

The particular type of knee pain regarding the trigger hasn’t been specifically
identified yet during the discussion. However, the occurrence of knee pain may be
initiated with some several risks factor such as body weigth, age, gender, and accident
as mentioned in the trigger that may damage the synergy of bone, joint, and muscle
or the involved components of lower extremities. Hence in this paper, the complaints
mentioned upon the patient anamnesis would be elaborated and analyzed in terms of
its pathophysiology encompassing the abnormal occurrence of function happens in
the area bone, joint, and muscle of knee.
CONTENT
Types of Knee Pain and the Major Causes
Below are the elaboration of major general flaws that may possibly causes knee pain that
derives from relevant risk factors such as body weight, accident and also age.[3]
1. Injuries
affect ligaments, tendons that surround the knee joint and bones, cartilage and
ligaments that form the joint itself. [4]
a. ACL Injury : the tore of ACL ligament that connect
shinbone to tight bone. usually due to sport
accident. [4]

b. Fractures : the broken of kneecap (patella), during

motor vehicle collisions or falls. Also, higher risk
factor for osteopororsis people to experience this
by stepping wrong. [4] Figure 1. ACL Injury
Available from:
mayoclinic.org
c. Torn meniscus : Meniscus is formed of rigid,
rubbery cartilage and plays a role as a shock
absorber between thighbone an d shinbone. It can
be torn due to a sudden twist on knee. [4]

d. Knee bursitis : An inflammation in the bursae that

causes ligaments and tendon glide smoothly
towards the joint. [4] Figure 2. Torn meniscus
Available from:
e. Patellar tendinitis. an inflammation and mayoclinic.org

irritation of patellar tendon that connects

quadricep muscle (on the front of the thigh) to shinbone. Majorly occurs in
athletes such as runners, skiers, cyclists. [4]

2. Mechanical Problem
a. loose body : degeneration of cartilage that causes it to break off and float in
the space of joint. [4]
b. illotibial syndrome : an extention of tough band tissue from outside of hip
the knee (illobitial band) that it may rubs against the outer part portion of the
femur. [4]
c. dislocated kneecap : the displacement of triangular bone (patella) from the
knee. [4]
 d. hir or foot pain : a pain in the area of foot or hip may alter changes in the
way of walking and hence placing more stress on knee joint. [4]

3. Arthritis.
a. Osteoarthritis : degenerative arthritis and is most common that happens. this
is a wear and tear condition that happens when cartilage in the knee
deteroriates with use and also age. [4]
b. Rheumatoid arthritis : an autoimmune condition that affects any type of
joint including knees. [4]
c. Gout : the accumulation of uric acid crystals I the joint. [4]
d. Pseudogout : the accumulation of calcium-containing crystal in the joint fluid.
[4]

e. Septic arthritis : the infection of knee joint that leads to swelling pain and
redness. [4]

Knee Pain in the Trigger

Upon the trigger, it was mentioned that :
- A 68 year old woman feel pain on the knee for the past 4 weeks especially
during walking long distance, up and down-stairs.
- Upset that she can’t no longer be active as she used to be
- Fell from the motorcycle 10 years ago, supported by the right knee.
- Having a BMI of 31.6 (BW=76kg, BH=155cm) which categorized as obese.
- Her mom also experienced the similar illness
- Experience a positive crepitaion on both knees, without warmth or swelling,
also a tenderness at the edge of distal femur and proximal tibia

Relating to the complaints, it is known that the complaint occurs when she is in the
older age despite the motorcycle she experienced 10 years ago and also she may
represents a wear and tear condition. The wear and tear condition describes a state
of inevitable damage such as injury that naturally happens as a result of a regular use
and aging. [5] Those criteria also indicates the occurrence of Osteoarthritis, and hence,
Mrs Tuti may possibly suffering from osteoarthritis.
However, she stated that the most sensitive part is the right knee compare to the left.
This occurrence might correlate to the accident of motorcycle which may be cause a
light fracture in the bone that’s not fully recovered.

Pathophysiology of Knee Pain: Osteoarthritis

By meaning, Osteoarthritis derived from 3 word (osteo:bone, arthr:joint, and it is:
inflammation). Therefore, osteoarthritis means an inflammation involving the joint
(cartilage) and bone.[5]

Osteoarthritis occurs in Synovial Joint or Diarthrosis that has a structure as follows:

1. The joint comprises of 2 bones that has articular cartilage, a connective
tissue that allows the 2 bones to glide towards each other without any friction.
[5,6]

2. Synovium in between the articular cartilage. it is a component that forms an

inner lining of the joint space. The space consists of connective tissue, blood
vessels, lympathic vessels, type a cells that clears cellular debris, and type b
cells that secrete a synovial fluid to lubricate the surface of articular cartilage.
[5,6]

The main issue of osteoarthritis starts with the degenerative loss of the articular
cartilage which results in the significant friction of each two bones during movement
this will further generate inflammation and pain in the nerve ending of the joint space.
In normal condition, the chondrocyte plays a major role of maintaining the articular
cartilage. in which it is embedded in the extracellular matrix that contains type II
collagen for structural support and proteoglycans that aggregates sugar and protein
molecules. Those extracellular components promotes elasticity and high tensile
strength that helps weight-bearing joints distribute weights so that the bone can bear
the weight and shock (occurs in hip, knees, and lower lumbar spine).[5]

In healthy people, chondrocyte demonstrate balance between a catabolic activity

(breaking down of cartilage) and anabolic activity (producing cartilage) through the
use of degradative and synthetic enzyme respectively. Thus, this indicates, the
increase of degradative enzyme will initiate cartilage loss through the loss of
extracellular matrix (collagen and proteoglycan). However, In osteoarthritis there
occur an increase of degradative enzyme outweigh the amount of syntethic enzymes
which caused by several risk factors.[5]
1. Age
By the time people age, the cartilage metabolism will no longer occurs. Instead,
cartilage degradation process will occur for a long time and hence is hard to
pinpoint the culprit.[5,7]
2. Inflammation
The role of IL-1,IL-6, and TNF as proinflammatory cytokines that promotes
proteolysis or a breaking of cartilage extracellular matrix which means it
increase catabolism.[5,6]
3. Joint injury, Mechanical Stress and Obesity
It highly correlates with the inflammation that will lead to osteoarthritis as well
as mechanical stress and obesity. An obese state will cause the joint to be
exhausted to withstand the load and hence increasing the risk factor of
ostoarthtritis [5,7]
4. Others
The neurologic disorder, medication and genetic also may contributes to the
occurrence of Osteoarthritis. particularly for genetic, genes that code for the
extracellular matrix such as proteoglycans have become obvious candidates.
[5,7]

The articular cartilage damage, will cause the chondrocyte to produce less
proteoglycans and more type II collagen. However, as time passes the collagen
production will switch to type I which doesn’t collaborate well with the proteoglycans.
Hence it will reduce the elasticity of cartilage matrix and allows it to breakdown. Over
the period of years, cartilage wont be able to keep up and this will lead to apoptpsis
or programmed cell death. It causes the cartilage to get weaker, softer, continue to
lose it elasticity and the debris will float into the synovial space. This event is also
called the joint mice. [5]
The type A cell will then try to remove the debris by the recruitment of lymphocyte
and macrophage in the synovia membrane. this immune reaction produces
proinflommatory cytokines that eventually cause synovitis or inflammation of
synovium. Along with it, fibrillation or cracks of articular cartilage also forms. The
process of cartilage erotion continues until the bone is exposed which will make it rub
with the other bone that will lead to bone eburnation. Ultimately, there will be an
outward growth of bone or osteophyte that makes joints look wider in the distal of
one bone and proximal side on the other bone. [5]

This occurrence will cause the person to oftenly feel stiffness in the morning but still
able to move in the end of the day. It also promotes pain such as burning sensation
and sharp ache and will surely worsen with activity. However, despite the stiffness
and pain, usually the people doesn’t develop swelling. [5]

CONCLUSION
Mrs Tuti is currently having an Osteoarthritis that initiates by several risks factors
which includes her age, the wear and tear condition, her body mass as well as her
genetics from mother. The several risk factors promotes the degradation process of
cartilage in the bone that involves the inflammation to occur and hence causes the
feeling pain that can be worsen with her activities.
REFERENCE
1. Campbell Fiona. Pathophysiology of osteoarthritis. Teach me Surgery
[Internet]. England. TeachMe Series;[2019 July 12][cited 2019 Oct 16].
Available from:
https://teachmesurgery.com/orthopaedic/principles/osteoarthritis/
2. Knee pain&tenderness: Differential Diagnosis by Location. Oregon. University
of Western State;[date uknown][cited 2019 Oct 16]. Available from:
file:///Users/devi/Downloads/Knee_Pain_and_Tenderness%20(1).pdf
3. Mayoclinic [Internet]. Osteoarthritis. The United States. Mayo Foundatoion for
Medical Education Research;[date unknown][cited 2019 Oct 16]. Available
from: https://www.mayoclinic.org/diseases-
conditions/osteoarthritis/symptoms-causes/syc-20351925
4. Mayoclinic [Internet]. Pathophysiology of knee Pain. The United States. Mayo
Foundatoion for Medical Education Research;[date unknown][cited 2019 Oct
16]. Available from: https://www.mayoclinic.org/diseases-
conditions/osteoarthritis/symptoms-causes/syc-20351925
5. Osteoarthritis[Internet]. The United States:Osmosis; 2019 Oct 1. Streaming
Video: 06.12 min. Available from:
https://www.youtube.com/watch?v=sUOlmI-naFs
6. Goldring S.R, Goldring M.B. Clinical aspects, pathology and pathophysiology of
osteoarthritis. J Musculoskelet Neuronal Interact 2006; 6(4):376-378. Available
from: http://www.ismni.org/jmni/pdf/26/30GOLDRING.pdf
7. Roach Helmtrud, Tilley Simon. The pathogenesis of Osteoarthritis.