Avascular necrosis is a complication of:
**Core Concept**
Avascular necrosis (AVN) is a condition characterized by the death of bone tissue due to a lack of blood supply. This can occur in various parts of the body, but it is most commonly associated with the femoral head, which is a crucial part of the hip joint.
**Why the Correct Answer is Right**
The correct answer is related to the femoral head because it is a weight-bearing joint that is prone to AVN due to altered blood flow patterns. The femoral head receives its blood supply from the medial and lateral circumflex femoral arteries, which can be compromised by various factors such as fractures, dislocations, or excessive corticosteroid use. This compromise can lead to ischemia and subsequent necrosis of the bone tissue.
**Why Each Wrong Option is Incorrect**
**Option A:** While corticosteroids can cause AVN, they are not the only cause, and this option is too narrow. Corticosteroids can cause AVN by inhibiting osteoblast activity and affecting the microcirculation of the bone.
**Option B:** Osteoporosis is a condition characterized by a decrease in bone density, but it is not directly related to AVN. Osteoporosis can increase the risk of fractures, which can then lead to AVN.
**Option C:** Rheumatoid arthritis is a systemic autoimmune disease that can cause joint damage, but it is not the most common cause of AVN. However, rheumatoid arthritis can lead to AVN due to chronic inflammation and altered blood flow patterns.
**Clinical Pearl / High-Yield Fact**
AVN is a common complication of femoral neck fractures, particularly those that are displaced or comminuted. It is essential to diagnose and treat AVN early to prevent long-term damage to the joint.
**Correct Answer:** C.