Diagnosis of aseptic loosening after hip arthroplasty

Aims: This Delphi consensus study aimed to achieve international expert agreement on clinical and radiological criteria for diagnosing aseptic component loosening in total hip arthroplasty (THA). The consensus involved revision hip surgeons from diverse healthcare settings worldwide, aiming to standardize diagnostic criteria and enhance clinical decision-making and future research comparability. Methods: A three-round Delphi study was conducted in accordance with Conducting and Reporting of Delphi Studies guidelines. A panel of 125 orthopaedic surgeons from 32 countries was approached based on geographical representation and experience in revision THA. In Round 1, experts listed clinical and imaging criteria; in Rounds 2 and 3, derived statements were rated on a Likert scale. Consensus was a priori defined as ≥ 70% agreement. A total of 43 experts completed Round 1, and 37 completed all three Delphi rounds. Results: Consensus was achieved on 25 clinical and radiological statements. Investigations for periprosthetic joint infection was unanimously considered the first step. Limping and pain were general indicators of loosening. Pain during weightbearing, hip rotation, start-up, or localized to the thigh was linked to femoral loosening. Pain at start-up, in the groin, or during activities was associated with acetabular loosening. Radiographs were the primary imaging modality, supported by serial radiographs and CT in uncertain cases. Key radiological indicators included progressive radiolucency, osteolysis, implant migration, broken screws, and cortical thickening. Conclusion: The consensus statements from this study establish key clinical and radiological parameters for diagnosing aseptic loosening in THA, recommending plain radiographs as the primary imaging modality and CT as secondary. The results lay the groundwork for more standardized diagnostic protocols and improved consistency in future clinical practice and research.