Lexicon on the Pathomechanics of the Native Hip Joint at Risk for Arthritis

BACKGROUND: Degenerative osteoarthritis (OA) of the hip often arises from structural abnormalities that alter load distribution, which leads to progressive chondrolabral damage. Although substantial advances have been made, the existing terminology in the field of hip preservation remains heterogeneous and inconsistently applied, limiting scientific communication and treatment standardization. The aim of this article is to link evidence from existing literature to develop a framework in the form of a structured lexicon, one that defines the morphological features and pathomechanical mechanisms that are relevant to the symptomatic, pre-arthritic hip. METHODS: This descriptive framework was developed through the synthesis of current biomechanical, radiographic, and clinical evidence, combined with expert consensus from an international, multidisciplinary panel. Foundational concepts were derived from basic science research, including tribology, mechanobiology, and contact mechanics, to establish a unified terminology. RESULTS: Three principal wear modes-instability, impingement, and mixed mechanisms-are proposed, corresponding to distinct pathological loading environments. Wear mechanisms include dysplasia with rim overload and stress-related cartilage failure, impingement with cam-induced shear or pincer rim conflict, and secondary inflammatory degeneration. Wear damage is classified by tissue involvement, encompassing labral degeneration, chondrolabral detachment, staged cartilage delamination, and subchondral bone changes (sclerosis, cystic change). By linking lesion topography to underlying mechanics, this framework has diagnostic and therapeutic relevance as well as encompasses radiographic measurements and clinical features of wear that are pertinent to hip instability and femoroacetabular impingement. CONCLUSIONS: This lexicon provides a coherent framework for pre-arthritic hip disease, establishing a shared terminology to guide basic-science research integration and the interpretation of current clinical practice in hip preservation.