Due to the current lack of standard definitions for rapidly progressive osteoarthritis of the hip (RPOH) in the literature, this observational study aimed to describe new diagnostic criteria and a grading system for the disease.
From a consecutive series of patients undergoing total hip replacement, 2 groups were selected: 1 with RPOH and 1 with primary hip osteoarthritis (POH), and their clinical, paraclinical, and demographic data were compared. The newly proposed clinico-radiological diagnostic criteria are based on characteristics of pain, joint mobility, and radiological assessment. The radiological grading system's inter- and intraobserver reliability was assessed through serial evaluations by 2 blinded reviewers.
From the total 863 cases, 82 cases (9.5%) of RPOH were identified and compared with 107 cases of POH. Mean age and disease bilaterality were similar, with a predominance of female patients in the RPOH group (P = 0.03). There were significant differences between the 2 groups in disease onset and aggravation, and intraoperative blood loss. The grading system showed significant inter- and intraobserver agreement (weighted kappa 0.93, and 0.89).
Our study presents distinctive, easily recognizable clinico-radiological characteristics of RPOH and confirmed the inter- and intraobserver reliability of the newly proposed grading system.