Impact of Preoperative Hypocalcemia on Complications Following Total Shoulder Arthroplasty: A Propensity Score Matching Study

Introduction Hypocalcemia is a common metabolic deficiency, notably impacting patients above 65 years of age. With the increase in volume of total shoulder arthroplasty (TSA), it is important to understand how hypocalcemia may impact complication rates. The aim of this study was to analyze the rates of complication following TSA in hypocalcemic patients, serum calcium < 8.5 mg/dL, compared to those with normocalcemia, serum calcium >8.5 mg/dL. Materials and methods Utilizing TriNetX, healthcare organizations within the United States were queried to create two cohorts consisting of patients undergoing TSA (Current Procedural Terminology (CPT): 23472) with hypocalcemia within one month of surgery (hypocalcemia cohort) and normocalcemia within one month of surgery (normocalcemia cohort). Primary outcomes included the odds of emergency department (ED) visit, inpatient admission, wound dehiscence, intraoperative fracture, postoperative hematoma or seroma, prosthetic joint infection, joint loosening, periprosthetic shoulder fracture, and reoperation. Outcomes were stratified by timeframe and were analyzed before and after propensity score matching. Results Prior to propensity score matching, patients with hypocalcemia had an increased rate of intraoperative fracture (odds ratio (OR) 2.9, p<0.01) and postoperative hematoma or seroma (OR 2.6, p < 0.01) at seven days postoperatively. At the two-month timeframe, hypocalcemic patients demonstrated increased odds of prosthetic joint infection (OR 1.7, p<0.05), joint loosening (OR 1.8, p<0.05), periprosthetic shoulder fracture (OR 1.8, p<0.05), and reoperation (OR 1.6, p<0.05). Results at two-years demonstrated similar findings. After propensity score matching, minimal clinical differences other than ED visits and joint loosening were seen between the cohorts. Conclusions Prior to propensity score matching, hypocalcemic patients demonstrated increased odds of implant-related complications within seven days, two months, and two years after TSA. However, after propensity score matching for patient demographics and comorbidities, only joint loosening and ED visits demonstrated a statistically significant difference between cohorts. Our results suggest that chronic hypocalcemia in patients with other comorbidities can potentially serve as a proxy for the odds of postoperative complications. Additionally, our results suggest that correcting hypocalcemia prior to TSA can potentially improve postoperative outcomes.