Serum C-reactive protein in patients undergoing elective shoulder arthroplasty. Prospective study.

BACKGROUND: The objective of the study was to determine the normalization curve of the serum C-reactive protein (CRP) in elective shoulder arthroplasty.

METHODS: A prospective study including 58 consecutive patients who had undergone elective shoulder arthroplasty. Forty-one patients had received a Reverse Shoulder Arthroplasty, 13 a Total Shoulder Arthroplasty and 4 a Hemiarthroplasty. Based on a pilot study, blood samples to determine CRP values were obtained at baseline (1 h before surgery), on the 1st, 2nd, 6th, 8th and 14th postoperative days. All the patients included presented no postoperative complications during inpatient stay or any re-admission during the three months after surgery.

RESULTS: Mean CRP values showed a rapid increase on the 1st postoperative day (7-fold higher than the baseline in cuff tear arthropathy, 11-fold higher in primary osteoarthritis, 1-fold higher in acute fracture) and reached a peak on the 2nd postoperative day (14-fold higher than the baseline in cuff tear arthropathy, 24-fold higher in primary osteoarthritis and 2-fold higher in acute fracture). After the 2nd postoperative day CRP values began to slowly decrease reaching the normal range in the 14th postoperative day.

CONCLUSIONS: Serum CRP levels after elective shoulder arthroplasty rapidly increase to reach a maximum peak after the 2nd surgery day and then slowly decrease to return to normality on the 14th day. Knowing the normalization curve of CRP can be a helpful tool to help in the diagnosis of acute infections in elective shoulder arthroplasty.