Generally speaking, what burr sizes are used for TKA and UKA procedures?

• A. 7mm burr for TKA; 6mm burr for UKA
• B. 5mm burr for TKA; 6mm burr for UKA
• C. 4mm burr for TKA; 5mm burr for UKA
• D. 6mm burr for TKA; 5mm burr for UKA

Answer: (B)

Burr size in knee arthroplasty reflects how much bone is removed during shaping and how precisely the surface needs to be prepared for the implant. For a total knee replacement, the surgeon works on larger surfaces (the distal femur and tibia) and aims for efficient, controlled bone removal that still preserves bone stock, so a 5 mm burr is a common, balanced choice. In unicompartmental knee arthroplasty, the preparation is confined to a smaller, more delicate area, where precise contouring is crucial for a good fit of the unicompartmental component; using a 6 mm burr helps achieve a smooth, accurate surface without under- or over-resecting, making it a typical pairing for UKA.

Other sizes are less standard for these general approaches, which is why the combination of a 5 mm burr for TKA and a 6 mm burr for UKA is the commonly referenced pairing.