Complex regional pain syndrome after multiple revision total hip arthroplasty surgeries

Background Persistent pain after total hip arthroplasty (THA) is a real concern for the surgeon and is a significant cause of patient dissatisfaction; periprosthetic joint infection (PJI), aseptic loosening, and instability are among the common causes of painful THA. However, few rare causes have been reported in the literature; the complex regional pain syndrome (CRPS) was reported to occur after primary hip and knee arthroplasties. Case presentation: We present a female patient who had bilateral hip resurfacing when she was 28 years old after being diagnosed with bilateral hip avascular necrosis; over 16 years, she was satisfied. She started developing pain in her right hip in 2019, diagnosed as aseptic loosening, and a revision using a cementless THA was performed. Six months later, she was diagnosed with PJI, which was treated in two stages; after the first-stage revision THA, the patient complained of persistent pain in her lower leg with a burning sensation and change in skin color, not responding to conservative lines. During the second-stage revision THA and after receiving spinal anesthesia, the skin color of the right lower limb changed to normal. The postoperative diagnosis was made as CRPS, treated effectively with sympathetic block. At six months postoperative, the patient was pain-free, and the implants showed proper position. Conclusions: Although rare, CRPS could cause persistent pain after repeated hip surgeries, and the diagnosis is reached mainly by exclusion.