PMC6616359_01
(A) Initial anteroposterior radiograph shows no significant findings except for mild pistol grip deformity on right hip and (B,C) small head-neck offset compared with left hip.
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Standard radiographic findings were normal except for mild pistol grip deformity in the right hip (Fig. 1).
(A,B) Computed tomography axial planes indicate normal femoral neck anteversion on both hips, (C) multiplanar reconstruction shows herniation pit at lateral femoral head-neck junction on the right hip. (D) Bone scintigraphy scanning shows increased uptake in both femoral necks.
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Computed tomography multiplanar reconstruction showed a herniation pit indicating cam-type femoroacetabular impingement at the lateral femoral head-neck junction (Fig. 2A-C). Bone scintigraphy showed increased uptake in both femoral necks, indicating possible stress fractures (Fig. 2D).
(A) T1 weighted MRI showing macroscopic fracture (white arrows). Fracture measures >=50% of femoral neck width in coronal plane on right hip and <50% of femoral neck width in coronal plane on left hip. (B) MRI on short tau inversion recovery (STIR) sequence showing clear bone marrow edema in right femoral neck and slight bone marrow edema in left femoral neck.
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Findings from magnetic resonance imaging (MRI) of the pelvis indicated fracture on the compression side of the distal portion of each femoral neck (Fig. 3).
(A-C) Postoperative radiographs obtained immediate after bilateral internal fixation with cannulated screw. (D) Arthroscopic observation on the right hip showing cleavage at labro-cartilage junction and acetabular cartilage delamination (black arrow). AL: acetabular labrum, FH: femoral head (E) Photomicrograph obtained from bone marrow of right iliac crest. Thin bone trabeculae noted. (Hematoxylin and eosin stain) (F) Undecalcified bone section. Increase in unmineralized osteoid (pink stain) compared with mineralized bone (bluish-green stain). (Villanueva-Goldner stain).
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We considered the patient's past medical history, reviewed the risks and benefits of a surgical procedure, and decided to perform bilateral internal fixation with two 6.5-mm cannulated screws under general anesthesia (Fig. 4A-C). The patient also had cleavage at the labro-cartilage junction and subsequent acetabular cartilage delamination classified as zone 2 grade 1 according to Konan's classification (Fig. 4D). Histopathological examination showed the bone trabeculae to be relatively thin, considering the patient's male gender and age (Fig. 4E). The undecalcified bone section showed an increase of unmineralized osteoid, suggesting the presence of osteomalacia (Fig. 4F).