In clinical practice, right knee inflammation and pain is frequently considered to be caused by arthritis, gout, or cellulitis. In this case, a 49-year-old female patient who experienced recurrent right knee inflammation and pain was initially diagnosed with cellulitis. However, her right knee refractory pain and local skin damage showed conflicting results. A computed tomography scan and biopsy were performed and necrotizing fasciitis was revealed. Fasciotomy, repeated debridement and subsequent above-knee amputation were perfoemed. The infection was eventually controlled and she was then discharged. For patients with recurrent right knee inflammation and refractory pain, when the antibiotic treatment is not effective and the clinical manifestation mismatches with pain score, necrotizing fasciitis must be considered as a possible differential diagnosis for punctual treatment.