IL4 and avascular necrosis: For patients with a diagnosis of sterile bone necrosis (avascular necrosis), a statistically significant result was the positive correlation between IL-4 and SDMA, meaning that in the patients studied, an increase in IL-4 entailed an increase in SDMA (p = 0.04); arginine and homoarginine were also shown to be co-variant (p = 0.009); the other correlations were not statistically significant (Figure 4C).