Evaluation of Radiographic Outcomes after Core Decompression for Osteonecrosis of the Femoral Head: The Beijing University of Chinese Medicine X-ray Evaluation Method

Background: Joint-preserving treatments for osteonecrosis of the femoral head (ONFH) are an area of significant interest in orthopaedics as they may restore function and provide durable benefit to patients who would otherwise require early total hip arthroplasty. Studies reporting the outcomes for these procedures generally rely on a combination of radiographic and clinical outcomes. However, there is not currently a standardized radiographic scoring system that allows for objective reporting of radiographic outcomes following these procedures. This article introduces a novel scoring system (Beijing University of Chinese Medicine X-ray evaluation, BUCMXE) based on Anteroposterior (AP) hip radiographs to allow for objective evaluation and comparison of postoperative outcomes following joint-preserving treatments for ONFH. Methods: The proposed scoring system utilizes AP radiographs of the hip and consists of a total score (0-10) derived from the sum of subscores in 3 domains: femoral head morphology, osteonecrotic lesion, and degree of osteoarthritis. Each radiographic parameter is scored from 0 (normal) to 3 or 4 (advanced disease). The scoring model was retrospectively applied to a cohort of patients who had undergone core decompression and cancellous bone grafting procedures by the principal investigator. Results: The BUCMXE provided a clear and reproducible means of quantifying and communicating radiographic changes over the course of follow-up in our study cohort. Statistical analysis demonstrated that the BUCMXE was sensitive to detect the radiographic changes associated with the index procedure. The median total score was reduced from 3 preoperatively to 2 at the initial (3-month) follow-up for this cohort. This change was attributable to the obvious improvement of osteonecrotic lesion in patients who had more advanced disease at the time of their procedure. Conclusion: The BUCMXE system allowed for objective quantification of radiographic changes following joint-preserving hip surgery in our cohort. Statistical analysis of BUCMXE scores demonstrated that the scoring system was sensitive to detect subtle radiographic changes associated with disease progression in the follow-up period. Level of Evidence: Therapeutic Level III .