Mutilating Multifocal Osteoarthritis: A Challenging Diagnostic Entity

Introduction: Multifocal mutilating osteoarthritis or multiple joint osteoarthritis (MJOA), is a rare entity. It is responsible for severe joint destruction, which may mimic neuropathic or metabolic arthropathies. These extreme forms lead to major functional disability and represent a significant diagnostic and therapeutic challenge. Case Presentation: We report the case of a 73-year-old patient, a candidate for total hip arthroplasty, referred from the orthopedic surgery department for evaluation of polyarticular involvement. He had experienced mechanical polyarthralgia for ten years, affecting the large joints of both the lower and upper limbs, with progressive worsening over the past year, resulting in to major functional impairment. Clinical examination revealed severe genu varum and bilateral talus valgus deformities, resulting in limping and the need for walking aids. Imaging demonstrated severe and mutilating multifocal osteoarthritis, including Kellgren-Lawrence grade IV knee osteoarthritis, involvement of the ankle, hip osteoarthritis with acetabular protrusion, and eccentric glenohumeral osteoarthritis. The diagnosis of multifocal osteoarthritis (MJOA) was established after an exhaustive diagnostic workup that excluded secondary causes. Given the severity of the polyarticular involvement, prosthetic surgery was considered; however, the patient ultimately did not undergo the procedure, highlighting the functional and therapeutic complexity of this phenotype. Discussion: Several secondary arthropathies may mimic MJOA, including neuropathic arthropathies, metabolic disorders, and chronic infections. Clinical and radiological similarities make the diagnosis challenging. This case emphasizes the importance of a rigorous diagnostic approach in order to avoid inappropriate therapeutic management. Conclusion: Recognition of these rare forms helps prevent diagnostic delay, improves understanding of the evolutionary spectrum of MJOA, and allows optimization of functional management strategies.