title: Differentiation between osteoarthritis and psoriatic arthritis: implications for pathogenesis and treatment in the biologic therapy era.
abstract: Rheumatologists have long considered OA and PsA as two completely distinct arthropathies. This review highlights how some forms of generalized OA and PsA may afflict the same entheseal-associated anatomical territories. While degeneration or inflammation may be clearly discernible at the two extremes, there may be a group of patients where differentiation is impossible. Misdiagnosis of a primary degeneration-related pathology as being part of the PsA spectrum could lead to apparent failure of disease-modifying agents, including apparent anti-TNF and apparent IL23/17 axis therapy failure. This is not a reflection of poor clinical acumen, but rather a failure to appreciate that the pathological process overlaps in the two diseases. Whether the category of OA-PsA overlap disease exists or whether it represents the co-occurrence of two common arthropathies that afflict the same anatomical territories has implications for the optimal diagnosis and management of both OA and PsA.
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds, UK and Department of Radiology, Charité Medical School, Berlin, Germany. Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds, UK and Department of Radiology, Charité Medical School, Berlin, Germany. d.g.mcgonagle@leeds.ac.uk.
authors.forename: Dennis
authors.initials: D
authors.lastname: McGonagle
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds, UK and Department of Radiology, Charité Medical School, Berlin, Germany.
authors.forename: Kay-Geert A
authors.initials: KG
authors.lastname: Hermann
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds, UK and Department of Radiology, Charité Medical School, Berlin, Germany. Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds Musculoskeletal Biomedical Research Unit, Chapel Allerton Hospital, Leeds, UK and Department of Radiology, Charité Medical School, Berlin, Germany.
authors.forename: Ai Lyn
authors.initials: AL
authors.lastname: Tan
mesh_terms: D015535:Arthritis, Psoriatic / Q000175:diagnosis* / Q000188:drug therapy* / Q000209:etiology; D001688:Biological Products / Q000627:therapeutic use*; D003937:Diagnosis, Differential; D019468:Disease Management; D006801:Humans; D008279:Magnetic Resonance Imaging; D010003:Osteoarthritis / Q000175:diagnosis* / Q000188:drug therapy* / Q000209:etiology; D010641:Phenotype; D012216:Rheumatic Diseases; D016896:Treatment Outcome
chemical_list: D001688:Biological Products
keywords: enthesitis; osteoarthritis; pathogenesis; psoriatic arthritis; therapy