There seems to be LOOSE BODIES IN KNEE.
Loose bodies are degenerative material formed from the lubricant liquid inside the knee joint.
CT / MRI
of Knee joint would help in diagnosis.
So post the reports in this forum and treatment modalities can be discussed based on that.
Meanwhile you may try physiotherapy
of knees which will include strenghtening of Quadriceps.
If indeed there are loose bodies, then ARTHROSCOPIC SURGERY
of knee Joint would help.