Knee Osteonecrosis

Osteonecrosis (ON) of the knee is broadly categorized into two main types: spontaneous and secondary ON [1, 2]. Spontaneous ON of the knee, also known as SPONK, was first recognized as a distinct condition by Ahlback et al. in 1968, characterized by the absence of an identifiable cause [1, 3]. However, in recent times, SPONK is often regarded as a consequence of a subchondral insufficiency fracture of the knee (SIFK). On the other hand, secondary ON of the knee is similar to the more commonly understood osteonecrosis of the hip and is linked to various conditions that interrupt blood flow, such as prolonged use of steroids or alcohol consumption. The categorization of post-arthroscopic ON remains debatable among researchers; some consider it a secondary cause, while others view it as a distinct condition [2]. Despite the differing clinical manifestations of each type, the severity of the disease is evaluated using universal classification systems, and treatment strategies are generally consistent across both types.