Characteristics of Osteonecrosis of the Femoral Head After COVID-19 Compared to Corticosteroid-Associated Osteonecrosis of the Femoral Head: A Multicenter, Large Database Study in Japan.

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been associated with systemic complications in addition to respiratory symptoms, including potential musculoskeletal disorders, such as osteonecrosis of the femoral head (ONFH). The aim of this study was to determine the difference between ONFH after COVID-19 and corticosteroid-associated ONFH using a large-scale ONFH database.

METHODS

We analyzed 5,371 registered ONFH patients from a large multicenter Japanese database, identifying 20 patients (32 hips) who developed ONFH after COVID-19 (COVID-19 group). These were compared with 693 corticosteroid-associated ONFH patients (1,197 hips) from 2020 to 2024 who were unrelated to COVID-19 (corticosteroid group). Patient demographics, Japanese Investigation Committee (JIC) type and stage classification, duration of corticosteroid administration, maximum daily dose, and corticosteroid-pulse therapy were assessed.

RESULTS

Patients in the COVID-19 group had significantly shorter corticosteroid administration (2.3 ± 2.9 versus 44.9 ± 65.1 months, P < 0.0001) and lower maximum daily dosages (28.1 ± 19.8 versus 53.2 ± 117.3 mg, P = 0.011). Fewer patients received pulse therapy (15.0% versus 49.4%, P = 0.0025). The COVID-19 group showed a notable men predominance (P = 0.008), and the proportion of JIC type C2 was high (P = 0.027).

CONCLUSIONS

Osteonecrosis of the femoral head after COVID-19 showed the features of lower corticosteroid use, higher prevalence in men, and higher rate of JIC type C2 compared to corticosteroid-associated ONFH, underscoring the potential impact of COVID-19-related thrombotic pathways. Physicians should be aware of these features and perform appropriate tests as early as possible in COVID-19 patients who have musculoskeletal symptoms, even if corticosteroid use is low.