Bone & Muscle problems

My 6.6 years old  son is having protruding bone in right leg (pic attached). His weight is 21 kg and height 4 feet. What is the cause of this?? Is it due to some deficiency?? Please advice.

I have severe pain from my knee to my ankle that is unbearable and constant.It's affecting my ability to perform daily activities.what could it be?

Pain at the lower point of tail bone in spinal cord Disc bulge in the reports of MRI report Pain from hip to legs till knees at one side of body

Pain at the lower point of tail bone in spinal cord Disc bulge in the reports of MRI report Pain from hip to legs till knees at one side of body

Severe Pain is felt near Knees from 15 days. Walking has become very difficult. There is very much swelling on knees. Please advise.

Severe Pain is felt near Knees from 15 days. Walking has become very difficult. There is very much swelling on knees. Please advise.

When I walk it is very painful since few days.I eat some pain killer and visit to physiotherapist but the pain is not cure then I did X-ray and I share the X-ray plate.Please advised me how I get relief from the pain.

My foot pain plz check mri and suggest me and mainly pain in back side foot plzz make a good suggestion about pain

Got pain and discomfort on the left leg near the ankle area. Please suggest medicines and remedies. Thank you in advance

I had ACL surgery around a month back. After 1 month of surgery, I was able to start walking for short time. Yesterday I walked for some more time following which today I'm having pain and swelling at knee and the muscle above knee. I'm following RICE method to reduce the pain and swelling. I wanted to know is it normal to have pain and swelling after walking too much? How can I avoid it in future and after how long after the surgery, I can start walking as normal?