Osteoarthritis is one of the most common forms of arthritis. It causes swelling and inflammation in the joints. Most common reason is aging but young people are also prone to this problem. It causes pain, inflammation, joint stiffness and immobility because of the wear and tear of cartilage and loss of collagen. So, it is a no brainer that eating food rich in collagen would give joint pain relief that is the result of collagen loss.
Gelatin is mainly made up of amino acids. Amino acids are the building blocks of protein.
Depending on the process almost 99% of gelatin is amino acids, as shown above it has some other nutrient value also. 
Glycine = 22%
Proline = 12%
Hydroxyproline = 12%
Glutamic Acid = 10%
Alanine = 9%
Arginie = 9%
Aspartic Acid = 9%
Other Nutrient value = 22% (of which almost 1.90% Valine)
This composition is variable according to source of gelatin.
Glycine and Proline, two amino acids richly present in gelatin, are essential in collagen formation. Plenty of research and studies have shown that taking pure gelatin supplement reduces pain related to osteoarthritis, osteoporosis and injuries during exercise and sports.
These amino acids are essential for the proper functioning of other organs as well. These amino acids also provide energy to the body.
Valine is an amino acid that a human body cannot make. So we have to take such diet which is rich in Valine, like pure gelatin.
Studies and Researches
According to U.S. national library of medicine, some clinical studies showed that taking gelatin as a supplement may reduce joints pains and improve their function.
A study showed significant amount of reduction in pain and joint stiffness of patients suffering from osteoarthritis, who took gelatine supplement for 70 days. 
In another study, 175 patients were given either gelatin supplement or placebo. The patients who took daily 10 gram of gelatin supplement along with calcium and vitamin C experienced significant improvement in joint mobility, pain and stiffness. 
Drinks for Joint pain Relief
Gummy Treats for healthy Bones.
VIOLA, a delicious yummy gummy treat for glowing skin, healthier gut, focused brain and not to forget strong bones. This gummy recipe is great for joints pain relief and osteoarthritis. You can experiment with different juices like cherry, orange, pineapple and peach or carrot juice.
The great thing about gelatin is that kids and older people can equally enjoy the treats made from it. The health benefits are remarkable as well as the taste.