Three-dimensional mapping of necrotic lesions for early-stage osteonecrosis of the femoral head.

BACKGROUND

There is a scarcity of evidence regarding the potential relationship between the size and location of necrotic lesions, which must be understood to provide optimal joint-preserving treatment. The purpose of this study was to characterize the distribution patterns of necrotic lesions of varying sizes in early-stage osteonecrosis of femoral head (ONFH) with the use of three-dimensional mapping.

METHODS

We retrospectively evaluated clinical CT images of the hips that were performed in the Third Hospital of Hebei Medical University from January 2018 to December 2022 and collected all CT images diagnosed with stage I and II ONFH. Three-dimensional structures that included both necrotic lesions and normal areas of the femoral heads were reconstructed and divided into eight regions to record their size and location. CT images for all lesions were superimposed onto a standard template, and three-dimensional mapping was created to determine the presence of concentrated areas of lesions.

RESULTS

In a cohort of 143 patients with stage I and II ONFH, a total of 150 hips were reviewed. For lesions with less than 15% of the femoral head volume, necrotic lesions predominantly involve regions I, III, and V, with region I showing concentration. For lesions with volumes ranging from 15 to 30%, necrotic lesions exhibited a wider distribution across regions I, II, III, IV, V, and VII, with significant concentrations in regions I, III, and V. For lesions exceeding 30% of the femoral head volume, the necrotic lesions were extensively distributed across nearly the entire femoral head, with a notable expansion of the concentrated necrotic areas.

CONCLUSIONS

The distribution of necrotic lesions varies with lesion size, with smaller lesions primarily concentrated in the anterior and medial regions of the femoral head, particularly in the anterosuperior region, while larger lesions expand to the lateral and inferior regions. These findings enhance existing classification systems and provide crucial insights for guiding hip-preserving surgical planning and approaches.