apophysitis

noun

apoph·​y·​si·​tis ə-ˌpäf-ə-ˈsīt-əs 

: painful inflammation of a bony outgrowth and especially the area of active growth at the end of bone (as of the heel or shin) where a muscle or tendon attaches

calcaneal apophysitis

Little League elbow is known medically as medial apophysitis …

—The Lexington (Kentucky) Herald Leader

… he probably has an inflammation of the growth plate along the rim of the pelvis. … This is called a hip flexor apophysitis and actually occurs frequently in young runners.

—Doug Cutter, The Richmond (Virginia) Times Dispatch