The Evolution of the Walch Classification for Primary Glenohumeral Arthritis

Our understanding of the pathology of and treatment for glenohumeral arthritis (GHA) has grown dramatically in the past few decades. Original observations regarding patterns of glenoid erosion, glenoid retroversion, and posterior humeral head subluxation in patients with primary GHA were documented in the 1980s and early 1990s. In the late 1990s, Walch et al proposed what is now the most widely used classification system to describe the characteristic pathology of GHA. Improved understanding of both premorbid and pathologic anatomies, along with advancements in imaging, have steered modifications in this classification system. These changes have improved its reliability and helped to further guide management decisions. The purpose of this article is to review the evolution of the Walch classification, understand the rationale behind the modifications, and discuss potential future developments.