Shoulder arthroplasty in the osteoporotic patient: do bisphosphonates make a difference?

Background: Osteoporosis (OP) affects much of the global population with a prevalence of 23.1% in women and 11.7% in men. This is relevant to orthopedists as osteoporotic patients have more postoperative complications following arthroplasty than nonosteoporotic patients. OP is also a risk factor for poorer medical and implant-related complications postoperatively for total shoulder arthroplasty (TSA) patients. To improve bone quality in this population, bisphosphonates (BP) are routinely utilized. This study aims to determine any differences in postoperative outcomes for osteoporotic TSA patients who are and aren't medically managed for their OP. Methods: The TriNetX database was queried to identify BP-managed or unmanaged osteoporotic TSA patients. Variables were identified using diagnosis and procedural codes. Patients were included if they had OP and underwent primary TSA and excluded if they had prior shoulder hemiarthroplasty, prior prescription for OP drugs other than BPs, or lacked a minimum of 2 years follow-up. Patients were propensity-matched into 2 cohorts: (1) those receiving BP therapy within 3 years of the index surgery (BP group) and (2) patients without any history of OP treatment (noTx group). Rates of periprosthetic fracture, postoperative infection, prosthetic joint infection (PJI), intraoperative fracture, osteolysis, mechanical loosening, dislocation, and revision surgery were examined at 3 months, 1 year, and 2 years postoperatively. Outcomes between cohorts were compared using odds ratios. All statistical analyses were performed via TriNetX in-suite software. Results: We identified 7,208 patients between the BP and noTx groups. Average ages for the BP group and noTx group were 73.6 ± 8.6 and 73.6 ± 9 years respectively. The BP group was less likely to experience periprosthetic fracture [0.7% vs. 1.2%, odds ratio (OR) 0.565 (0.345, 0.925)], PJI [0.8% vs. 1.8%, OR 0.45 (0.292, 0.695)], and revision TSA [0.8% vs. 1.4%, OR 0.59 (0.371, 0.934)] within 90 days, PJI [1.6% vs. 2.7%, OR 0.56 (0.401, 0.778)], revision TSA [1.6% vs. 2.6%, OR 0.62 (0.443, 0.854)], and mechanical loosening [0.8% vs. 1.4%, OR 0.57 (0.365, 0.901)] at 1 year, and PJI [2.1% vs. 3.4%, OR 0.61 (0.459, 0.817)] and mechanical loosening [1.4% vs. 2.1%, OR 0.67 (0.466, 0.953)] at 2 years. There were no significant differences in rates of non-PJI postoperative infection, or dislocation at 90 days, 1 year, or 2 years. Conclusion: Bisphosphonate-treated OP was associated with lower rates of periprosthetic fracture, osteolysis, and revision TSA within 90 days, revision TSA at 1 year, and PJI and mechanical loosening at both 1 and 2 years.