Peroxiredoxin 4 expression in rapidly destructive coxarthrosis potentially serves as a candidate tissue-level indicator associated with the local antioxidant status.

Rapidly destructive coxarthrosis (RDC) is a clinically challenging progressive hip disorder characterized by severe and accelerated joint destruction; however, the local antioxidant response in RDC remains unclear. In steroid-associated osteonecrosis of the femoral head, peroxiredoxin 4 (PRDX4) has recently been suggested to be retained in relatively preserved tissue areas but reduced in association with oxidative injury. Given its established roles in antioxidant defense and tissue protection under oxidative stress, PRDX4 was considered a plausible marker for assessing the local redox response in RDC. This study examined the clinicopathological significance of PRDX4 and its relationship with oxidative damage in femoral head lesions from patients with RDC mainly using histopathology and immunohistochemistry. Femoral head specimens from patients with RDC undergoing hip replacement were compared to those from primary osteoarthritis (POA) controls. PRDX4 expression was significantly lower in RDC than in POA, whereas inflammatory markers and the density of multinucleated osteoclast-like cells were significantly higher. When the RDC cohort was analyzed internally, weak PRDX4 expression was significantly associated with strong 8-hydroxy-2'-deoxyguanosine (8-OHdG) expression, showing a significant inverse correlation. Strong PRDX4 expression was closely related to a lower empty lacunae burden and showed an exploratory association with osteoclast-like cell-rich remodeling changes within RDC. These findings suggest that reduced PRDX4 expression is associated with oxidative injury and may be linked to histopathological changes reflecting more advanced tissue injury. Therefore, PRDX4 may serve as a candidate tissue-level indicator associated with the local antioxidant response in RDC.