Osteoporosis and osteoporosis therapies as determinants of implant fixation failure in arthroplasty and spinal fusion constructs: a position statement from the Fracture Working Group of the Council of Scientific Advisors of the International Osteopor

This expert position statement reframes arthroplasty and spinal fusion complications under the unified endpoint of implant fixation failure, defined as loss of mechanical integrity of the bone-implant unit over time. It synthesizes mechanistic and clinical evidence and provides evidence-informed recommendations for peri-operative bone health optimization. BACKGROUND: Osteoporosis is traditionally conceptualized as causing fragility fractures. However, compromised bone quality also affects the integrity of bone-implant constructs, influencing whether implants maintain fixation, interfaces remain stable, and fusion constructs consolidate. OBJECTIVE: To synthesize mechanistic, translational, and clinical evidence on how osteoporosis and osteoporosis pharmacotherapies influence implant fixation failure across arthroplasty and spinal fusion, and to provide evidence-informed clinical recommendations for peri-operative bone health assessment and optimization within a unified construct-level framework. METHODS: A position statement was developed following a structured literature search. Evidence was synthesized narratively by defining implant fixation failure as a construct-level outcome encompassing periprosthetic fracture, loosening, subsidence, pseudarthrosis, and junctional failure. Recommendations were categorized by strength (strong or conditional) and certainty of evidence (high, moderate, or low). RESULTS: Low bone mineral density (BMD) is associated with implant fixation failure across arthroplasty and spinal fusion. In arthroplasty, randomized trials demonstrate preservation of periprosthetic BMD with bisphosphonates, while registry analyses suggest improved implant survival. In spinal fusion, antiresorptive and anabolic therapies influence fixation-related parameters, with anabolic agents showing the most consistent evidence for enhanced fusion mass and earlier union. Much of the literature relies on radiographic or biomechanical endpoints rather than definitive outcomes. CONCLUSIONS: Viewing arthroplasty and spinal fusion complications through a shared construct-level perspective provides a coherent link between osteoporosis and reconstructive durability. Systematic peri-operative bone health optimization may improve construct longevity, although more definitive outcome-driven trials are needed. Closer integration between orthopedic surgeons and osteoporosis specialists will be central to advancing peri-operative bone health care.