This article deals with some of the concepts related to the progression of osteoarthritis. These statements were given by prominent researchers and resulted in a debate between two prominent groups of researchers against each other. All of these took place actively in the 19th century where the publications of research scholars were opposed to that of the scholars in the other group.

William Bauer told that mechanical trauma can result in OA directly or indirectly. By the 20^th century ideologies were majorly split into two ‘inflammation’ and ‘no inflammation’. Henry Fuller and Robert Todd suggested that OA occurred due to disruption to nutrients required for knee development and doesn’t occur through inflammation. On the other hand, Garrod and others stated that OA is partly degenerative and partly inflammative. Hence the study for OA continued under these two domains and each group of scientists trying to prove the other is false. But this situation can be compared to two sides of a coin where both the situations cannot be neglected. Hence both the domains of OA cannot be neglected.

Some others say that OA is a neurogenic immune homeostatic disorder. Garrod in 1988 stated that OA is associated with lesions in CNS in a peculiar manner. CNS refers to the central nervous system which constitutes the brain and spinal cord. The brain is the mastermind of the body which generates electrochemical signals to simulate several neurons in the body. The spinal cord is known as a warehouse of reflexes. Reflex is an involuntary (cannot be controlled by conscience) rapid sequence of actions. Reflex can be best explained by several experiments.

When someone comes to hit you; you will either duck or catch his hand spontaneously and this is known as a reflex and the spinal cord or vertebral column is responsible for this.

The reflex of the knee is tested by the doctor who takes a rubber mallet and taps it on the knee and what interestingly happens is that the knee starts to retract and the patient can feel the pain. In case of OA or any knee-related diseases, the patient cannot experience any pain and hence the doctor understands that there is some abnormality in the knee. Hence we can understand that there is a connection between the knee’s ability and CNS and an interruption in this connection can lead to knee diseases.

We have to understand that this is a basic relation and there are other complex associations between them and require more complex methods like electrophysiology and pharmacology to understand them. Later it was proposed that changes in the sympathetic nervous system can also lead to OA.

The sympathetic nervous system is a part of the autonomic nervous system. This can be correlated to the word ‘increase’. The sympathetic nervous system works in response to stimuli like emotions and increases some parameters of the human body like heart rate, eye dilation, blood sugar, blood pressure, etc. this proposal paved the way for using micro-circuitry to correct it.

There is also another field on which the world is divided into two namely ‘nociceptive’ and ‘neuropathic’ where nociceptive refers to pain resulted due to receptors. These are present at target and send signals to the brain via the spine more or less like the reflex. On the other hand neuropathic refers to the condition where pain occurs due to nerves. The following table shows the difference between these two. 

Nociceptive	Neuropathic
Receptor-mediated pain	Nerve mediated pain
Doesn’t affect nerves	Affects the nerves
Due to painful stimuli	Due to inflammation

However, some of the debate topics have not been resolved even till now but a lot of research articles about the progression of the disease and its underlying phenomena have been published. This is one of the cases in which a debate has done some good to the field of science!

HAPPY READING!!

Osteoarthritis can be mainly classified into two. They are primary and secondary. The criterion for this classification is based on the different types of risk factors. Primary OA is mainly due to age where the reason for cartilage breakdown is not known or maybe due to genetics. Secondary OA is due to direct injury through sports or trauma, stress, inflammation, or other metabolic diseases. In this case, the cause may localize.

OA grading

Grading is the process of classifying the disease based on its extent or severity. OA has been graded into 5 from grade 0 to grade 4

Stage number	Condition
0	Normal
1	Minor
2	Mild
3	Moderate
4	Severe

This was proposed by Kellgren and Lawrence and it is known as KL grading. The five grades have been proposed based on radiographic analysis of subjects. This was accepted as a standard measure by WHO in 1961. The grading has been done based on the narrowing of joint space and the formation of osteophytes.

• grade 0 (normal): no changes in knee x-ray
• grade 1 (minor): minimalistic joint space narrowing with possible osteophyte lipping
• grade 2 (mild): definite osteophytes and  joint space narrowing
• grade 3 (moderate): multiple osteophytes, definite narrowing of joint space and some sclerosis and possible deformity of bone ends
• grade 4 (severe): large osteophytes, marked narrowing of joint space, severe sclerosis and definite deformity of bone ends

Grade 0

Grade 0 is considered normal. The subject will not exhibit any features for OA. The x-ray image from this grade is taken as a standard and the other grades are compared with this grade.

Grade 1

Grade 1 is known as the minor. It can be considered as the initial grade. The joint space has just started to decrease. Osteophyte refers to excess bone growth. It is also known as bone spurs since spur refers to kind to sharp material. This bone growth can be observed as sharp spikes. Here there is very minimal growth of excess bone. Bone spurs occur only at the bones adjacent to the joint. There will be very minor loss of cartilage but this does not contribute to the narrowing of the joint space. Subject in this stage is not confirmed with osteoarthritis. However, subjects having any of the risk factors become more prone to the disease

Grade 2

Grade 2 is known as mild. In this grade, the narrowing of the joint space is more and is visible through the x-ray. There will be also more formation of osteophytes. This grade can be considered as the precursor to many complications like bone dislocation and rubbing. None of these complications are seen in this grade but these complications are soon to occur. The subject in this grade is confirmed with osteoarthritis. Special care has to be taken by those in this grade and through proper medications, they can prevent those further complications.

Grade 3

Grade 3 is known as moderate. Obvious damage occurs to the cartilage and the joint space narrows even at a faster rate. Swelling of the joints starts to occur in this stage. Erosion of cartilage becomes prominent in this stage. The joints become rougher due to spurs leading to stiffness. Inflammation occurs at regular intervals. Subjects can experience popping sounds from the knee.

Grade 4

Grade 4 is known as severe. It is the worst and highest grade of all. The changes become prominent and occur at larger scales. There will be no gap literally meaning the joint is absent. The bones start to rub over each other causing pain. The joint becomes stiff like a rock. The cartilage wears down and maximum growth of osteophyte is seen. Various cytokines are released at cartilage resulting in further death. Life would be dreadful for those in this grade. The arrow in the given X-ray indicates the bones are touching each other and there is no gap in between them.

HAPPY READING!!