noun
arthroscopy
Medical procedure in which a small camera is inserted into a joint to examine or treat it.
膝の痛みの原因を調べるために関節鏡検査を受けた。
I underwent an arthroscopy to investigate the cause of my knee pain.
内視鏡検査 is a broader term for endoscopic examination of internal organs, while 関節鏡検査 specifically refers to arthroscopy of joints.
Compound of 関節 (joint), 鏡 (scope), and 検査 (examination). A straightforward medical term.