Primary Reverse Shoulder Arthroplasty in Patients with Metabolic Syndrome Is Associated with Increased Rates of Deep Infection.

Abstract Background Metabolic syndrome (MetS) is an abnormal physiological condition that has been increasingly identified as a risk factor for complications after orthopedic surgery. Given the lack of information on the effect of MetS in shoulder arthroplasty (SA), this investigation analyzed the rate of postoperative complications, and implant survivorship free from reoperation and revision in patients with and without MetS. Methods Between 2007 and 2017, 4,635 adults who underwent a primary shoulder arthroplasty were collected and classified based on the presence or absence of MetS. MetS was defined as the existence of type II diabetes mellitus, and a minimum of 2 of the following diagnoses: hyperlipidemia, hypertension, and body mass index (BMI) ≥ 30 kg/m2 within 1 year of surgery. Of the 4,635 arthroplasties, 714 were performed in patients with MetS (289 total SA (aTSA), 425 reverse SA (RSA)) and 3921 in patients without MetS (1,736 aTSA, 2,185 RSA). Demographics, complications, reoperation and revision surgery were compared. Results At mean follow-up of 4.5 ± 2.3 years, 67 (9.4%) MetS patients and 343 (8.7%) non-MetS patients had sustained at least one postoperative complication (p = 0.851). Rotator cuff failure was the most common complication in 84 (1.8%) cases overall (MetS = 15, 2.1%; non-MetS = 69, 1.8%; p = 0.851) and in both MetS and non-MetS, followed by infection with 68 (1.2%) cases (MetS =10, 1.4%; non-MetS = 58, 1.2%; p = 0.913). For aTSAs, the most common complication was rotator cuff failure (84 shoulders, 1.8%); for RSA the most common complication was periprosthetic fracture (52 shoulders, 1.1%). In RSA deep infection (1.9% vs. 0.7%; p = 0.04), instability (3.1% vs. 1.5%; p = 0.04), and DVT/PE (0.5% vs. 0.3%; p = 0.03) were found to be significantly higher in patients with MetS compared to those without metabolic syndrome. Re-operations were observed in 36 (5%) MetS patients and 170 (4.3%) non-MetS patients (p = 0.4). Revisions were performed in 30 (4.2%) MetS patients and 127 (3.2%) non- MetS patients (p = 0.19). Kaplan-Meier five-year survivorship free from re-operation, revision, and prosthetic joint infection was equal between groups. Conclusions A preoperative diagnosis of MetS in patients undergoing primary shoulder arthroplasty did not significantly increase the risk of postoperative complications, infection, reoperation, or revision following primary shoulder arthroplasty. However, in the RSA subgroup, complications were significantly more common in patients with Mets. Individual risk factors may be more appropriate than the umbrella diagnosis of MetS prior to anatomic TSA. Level of Evidence Level III; Retrospective Cohort Comparison; Treatment Study;