Rapidly progressive hip osteoarthritis (RPOH) is a rare and severe form of osteoarthritis (OA), marked by the rapid degeneration and destruction of the femoral head, often within months. Despite its unclear etiology, several factors such as subchondral fractures and immune responses have been proposed as possible contributors. This narrative review aims to synthesize current knowledge on the pathogenesis, risk factors, clinical presentation, imaging features, and grading systems of RPOH. Predominantly affecting elderly females, RPOH presents distinctive challenges in both diagnosis and management due to its abrupt onset and severity. Known risk factors include advanced age, female gender, obesity, intra-articular corticosteroids use, and long-term hemodialysis. Clinically, RPOH is characterized by severe pain during active weight-bearing movements, despite patients presenting a normal range of motion during passive examination in the early stages. While several classification systems exist, there is no universal standard, complicating differential diagnosis and clinical approaches. This review emphasizes the necessity for early diagnostic methods utilizing specific biomarkers, rapid differential diagnosis, and targeted, personalized interventions based on individual risk factors.

Background/Objectives: Rapidly progressive osteoarthritis of the hip (RPOH) has unique diagnostic and surgical challenges due to rapid joint degeneration and acetabular structural alterations. This study aimed to investigate correlations between preoperative spinopelvic geometry and anterior acetabular wall bone stock deficiency in RPOH patients and introduce an advanced imaging measurement techniques for cases with amputated femoral heads. Methods: A prospective observational study was conducted that enrolled 85 patients, comprising 40 with unilateral RPOH (Zazgyva Grade II or III) and 45 controls with primary osteoarthritis (OA). Preoperative spino-pelvic parameters (pelvic tilt—PT, sacral slope—SS, lumbar lordosis—LL, and T1 pelvic angle) and acetabular anterior wall characteristics (anterior center edge angle—ACEA, anterior wall index—AWI, and anterior acetabular surface area—AASA) were measured using standardized radiographic and CT imaging protocols, including a new methodology for acetabular center estimation in femoral head-amputated cases. Results: Significant differences were identified between RPOH and primary OA patients in the PT (22.5° vs. 18.9°, p = 0.032), SS (37.8° vs. 41.1°, p = 0.041), T1 pelvic angle (14.3° vs. 11.8°, p = 0.018), and anterior center edge angle (25.3° vs. 29.7°, p = 0.035). RPOH patients exhibited pronounced spinopelvic misalignment and anterior acetabular deficiencies. Conclusions: RPOH is associated with spinopelvic misalignment and anterior acetabular wall deficiency. Accurate preoperative diagnosis imaging and personalized surgical approaches specifically addressing acetabular bone stock deficiencies are mandatory in these cases.