This systematic review of 16 studies (664 hips) defines the natural history of untreated asymptomatic osteonecrosis of the femoral head. It answers the question: which lesions will progress to collapse, and can we predict who? The key stratifiers are lesion size and lateral location within the femoral head.
Before this systematic review, management of the asymptomatic contralateral hip in osteonecrosis was genuinely controversial — some surgeons advocated universal watchful waiting, others recommended prophylactic surgery for all. This paper resolved the debate by showing that a blanket watchful-waiting strategy fails 59% of patients, while also identifying the narrow subgroup. Small, medial lesions. Where observation is defensible.
When you discover an asymptomatic osteonecrotic hip (most often the contralateral side in a patient presenting with one painful hip), measure the lesion: if it occupies <25% of the femoral head AND spares the lateral weight-bearing zone (type-A), observation is reasonable with close MRI follow-up. If the lesion is medium or large (>25%) OR extends laterally (type-B or type-C), counsel the patient that collapse is likely without intervention and discuss joint-preserving surgery. Core decompression or bone grafting. Before collapse occurs.
In your sickle cell patients specifically, treat asymptomatic osteonecrotic hips aggressively: 73% will collapse without intervention, the highest rate of any etiology in this review.
This systematic review of 16 studies (664 hips) defines the natural history of untreated asymptomatic osteonecrosis of the femoral head. It answers the question: which lesions will progress to collapse, and can we predict who? The key stratifiers are lesion size and lateral location within the femoral head.
Before this systematic review, management of the asymptomatic contralateral hip in osteonecrosis was genuinely controversial — some surgeons advocated universal watchful waiting, others recommended prophylactic surgery for all. This paper resolved the debate by showing that a blanket watchful-waiting strategy fails 59% of patients, while also identifying the narrow subgroup. Small, medial lesions. Where observation is defensible.
When you discover an asymptomatic osteonecrotic hip (most often the contralateral side in a patient presenting with one painful hip), measure the lesion: if it occupies <25% of the femoral head AND spares the lateral weight-bearing zone (type-A), observation is reasonable with close MRI follow-up. If the lesion is medium or large (>25%) OR extends laterally (type-B or type-C), counsel the patient that collapse is likely without intervention and discuss joint-preserving surgery. Core decompression or bone grafting. Before collapse occurs.
In your sickle cell patients specifically, treat asymptomatic osteonecrotic hips aggressively: 73% will collapse without intervention, the highest rate of any etiology in this review.