Keywords: (ESR); McPherson schema; abscess; aseptic loosening; c-reactive protein (CRP); culture-negative periprosthetic joint infection (PJI); deep surgical site infection (SSI); erythema; erythrocyte sedimentation rate; fever; histology; infection grade; intraoperative purulence; leukocyte esterase (LE); necrosis; painful prosthetic joint; periprosthetic joint infection (PJI) clinical features; periprosthetic joint infection (PJI) clinical findings; positive cultures; purulence; septic arthritis; septic arthritis criteria; septic arthritis definition; septic arthritis diagnosis; sinus tract; superficial surgical site infection (SSI); surgical site infection (SSI); synovial polymorphonuclear (PMN) percentage; synovial white cell count; toxic synovitis; undiagnosed periprosthetic joint infection (PJI).