Radiographic Classification Systems for Osteonecrosis of the Knee: A Review of Literature.

Knee osteonecrosis is a rare, yet debilitating disease that can lead to knee joint destruction and can be associated with significant pain and disability. Various imaging modalities have different roles in the diagnosis, staging, management, and determination of the prognosis in knee osteonecrosis. Plain radiographic images can show gross joint destruction and secondary arthritic changes. In addition, magnetic resonance imaging (MRI) has become the gold-standard imaging modality to diagnose osteonecrosis. Multiple classification systems have been developed for knee osteonecrosis based on these imaging modalities. The goal of these systems is to stage the disease and guide management. Better understanding of the pattern of the lesions and its morphometric characteristics may allow surgeons to reach a better consensus regarding the timing of surgical treatment, choice of implant, and overall disease prognosis in these unique patients. Due to the relative paucity of evidence, this review was conducted to evaluate different radiological classification systems utilized in osteonecrosis of the knee joint.