This was an IRB-approved retrospective study of 26 patients (mean age 30 years, 14 men) with FHN diagnosed in a tertiary orthopedic university hospital. Diagnosis of FHN was established in patients with a history of hip symptoms at clinical examination. All patients underwent biplanar radiographic imaging with supine AP pelvis views and cross table lateral view and subsequent MRI of the hip. FHN was graded according to the commonly recommended 2019 ARCO grading [12 (
link)]: I (negative x-rays): two hips; II (no fracture): four hips; IIIA (head collapse < 2 mm): 13 hips; IIIB (head collapse > 2 mm): 11 hips. Patients underwent preoperative MR arthrography at 3T (Skyra, Siemens Healthineers, Erlangen, Germany) for their hips including the application of traction according to a previously described technique [16 (
link),17 (
link)]. This included the acquisition of multiplanar proton-density (PD) weighted turbo spin-echo (TSE) imaging without fat saturation (coronal, radial and axial orientation) and a high-resolution axial-oblique 3D T1-weighted volume interpolated breath-hold examination (VIBE) sequence [18 (
link)]. Sequence parameters for the coronal PD-w sequence were repetition time (TR)/echo time (TE), 2600/11 milliseconds (ms), slice thickness of 2 millimeters (mm), 170 × 170 mm field of view, matrix size of 269 × 384, acquisition time (AT) of 3 min. Sequence parameters for the 3D T1-w VIBE sequence were TR/TE, 15/3.3 ms, slice thickness of 0.8 mm, 160 × 160 mm field of view, matrix size of 192 × 192, and an acquisition time of 8:46 min.
Modified Kerboul angles were measured for each of the patients from the MR images, according to the method of Ha et al., where the greatest extension was assessed in the midcoronal and midsagittal planes and summed, since measuring from only the coronal plane is not as accurate in the quantification of necrosis [19 (
link)]. Additionally, Tönnis scores to assess the degree of hip osteoarthritis were included, with grades from 0 (no osteoarthritis present) to 3 (large cysts, avascular necrosis, and severe narrowing of joint space) [20 (
link),21 (
link)] (
Table 1).
Ruckli A.C., Nanavati A.K., Meier M.K., Lerch T.D., Steppacher S.D., Vuilleumier S., Boschung A., Vuillemin N., Tannast M., Siebenrock K.A., Gerber N, & Schmaranzer F. (2023). A Deep Learning Method for Quantification of Femoral Head Necrosis Based on Routine Hip MRI for Improved Surgical Decision Making. Journal of Personalized Medicine, 13(1), 153.