Hip osteonecrosis after Covid-19: a review describes 864 cases without establishing the cause

A review dominated by case descriptions

Avascular osteonecrosis of the femoral head affects the part of the bone that forms the hip joint. The priority highlighted by the authors is to preserve this joint and its function through early diagnosis.

The review included 55 studies following a literature search conducted on April 1, 2024. Of these, 45 were case reports or case series, six were retrospective studies and four were cross-sectional studies. The available material provides access only to the PubMed abstract, not the full text.

These studies covered 864 cases. Both hips were reported to be affected in 274 of them, or 31.7%. This percentage describes the cases included in the review, not everyone who has had Covid-19.

After Covid does not necessarily mean because of Covid

The crucial point is that the available abstract contains no comparison that would allow the risk after infection to be measured. The 864 cases therefore cannot be used to calculate how common this complication is among people who have had Covid-19.

In 43 of the 55 studies, corticosteroid treatment was reported among the patients included. Hypertension, followed by diabetes, was the most common pre-existing condition. These characteristics complicate interpretation: the abstract does not allow the respective roles of the infection, treatments and underlying medical conditions to be distinguished.

The timing is therefore a clinical signal, not proof of causality. The predominance of case reports also limits how far the findings can be generalized.

Treatments described, but no strategy validated by this review

Total hip replacement was the most frequently reported surgical treatment. Several studies also described symptom improvement after bone decompression, known as core decompression.

Some studies included nonsurgical treatments, such as physiotherapy, anticoagulants, supplements and hyperbaric oxygen therapy. Their inclusion in the review does not demonstrate their effectiveness: the abstract provides no comparative results that would allow them to be ranked.

The practical message therefore remains limited to the diagnostic vigilance emphasized by the authors. This review does not justify either routine screening after Covid-19 or preventive treatment.

What we can take away

This review documents cases of osteonecrosis after Covid-19. It cannot estimate an individual's risk, attribute the cause to the virus or guide treatment selection.