A
A sinus tract communicating with the prosthesis
B
Elevated serum C-reactive protein (CRP)
C
Synovial fluid white blood cell (WBC) count greater than 3,000 cells/µL
D
Positive leukocyte esterase on synovial fluid dipstick
Explanation:The correct option is 'a'. The two major criteria for PJI are: 1) A sinus tract communicating with the joint, or 2) Two positive periprosthetic cultures with phenotypically identical organisms. The presence of either is definitive for PJI. Options B, C, and D are considered minor criteria.
Reference: Parvizi J, et al. The 2018 Definition of Periprosthetic Hip and Knee Infection: An Evidence-Based and Validated Criteria. J Arthroplasty. 2018;33(5):1309-1314.e2.