CPT® Coding Confusion

I'm having difficulty understanding the answer given in my workbook as 27331-LT for the following question:

Exploration with synovial biopsy by arthrotomy, left knee

CPT® code 27330 states Arthrotomy, knee; with synovial biopsy only
CPT® code 27331 states Arthrotomy, knee; including knee exploration, biopsy or removal of loose or foreign bodies

If I choose 27331 wouldn't that mean that you only have an option of the knee exploration, biopsy or removal of loose or foreign bodies because in code 27330 the ;(semi-colon) means that if you choose a code below that code category that you are not bringing over any description pass the ;(semi-colon)?

I look forward to clarification.

Thank you,

Marisol