Successfully treatment of acute shoulder arthroplasty infections strongly depends on the timing of treatment. The objective of this study is to determine the normalization curve of C-reactive protein (CRP) after shoulder arthroplasty

Prospective study including 63 patients undergoing shoulder arthroplasty (46 reverse shoulder arthroplasty (RSA) and 17 total shoulder (TSA)). Mean age 74.1 years old. 25 cuff deficient shoulders, 14 acute fractures, 19 primary gleno-humeral arthritis and 5 fracture sequel were included. Blood samples to determine CRP were obtained before surgery the day of surgery, 24 and 48 hours after surgery and then 6, 8 and 14 days after surgery (data of blood samples was determined based on a previous limited study). Co-morbidities that could interfere CRP were also recorded

Normal value of CRP before surgery (mean 1.28) slightly increases 24 hours after surgery (mean 3.92), reach maximum value at 48 hours after surgery (mean 6.91) and then slowly decreases to normalize at 14 days (6th day mean 3.80, 8th day 2.33 and 14th day 1.08). Normalization curve is not affected by age, diagnosis or type of arthroplasty

CRP after shoulder arthroplasty reaches maximum value at 48h and then slowly decreases to become normal at 14 days. Any deviation from this normalization curve may help in diagnosis and early treatment of acute shoulder arthroplasty infections