case_images: PMC10692435_01
case_images: Bilateral lower limb full-length radiographs taken in 2018. (A) Severe (Grade III) lateral femoral bowing, determined by drawing a reference line from the tip of the greater trochanter to the centre of the intercondylar notch and identifying its position being off the medial cortex using Park et al's grading system for anterolateral femoral bowing.
  (B) Lateral femoral bowing angle measured by the angulation between the proximal and distal quarters of the femoral diaphysis using Yau's method showing right and left lateral bowing angle of 13.5  and 16.9  respectively. (C) The standing anatomical femorotibial angle (FTA) measured 181.2  on the right and 181.6  on the left (yellow line), suggestive of a varus alignment.
  (D) Femoral neck-shaft angle (FSA) of 125.3  on right and 127.5  on left, consistent with varus hip alignment. Multiple transverse linear lucencies (white arrows) and cortical thickening at the mid to distal thirds of femoral shafts were seen.
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case_images: PMC10692435_01_JAFES-38-2-135-g001.jpg
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case_images: A bilateral full-length lower limb radiograph was performed in 2018 (Figure 1). AFF and bilateral chronic incomplete AFFs, in accordance with the ASBMR 2014 criteria. A review of her old radiographs revealed the presence of bilateral cortical thickening and multiple transverse linear lucent lines at the lateral femoral cortices since 2018, suggestive of chronic stress fractures with bony remodelling (Figure 1). There was bilateral Grade III (severe) lateral femoral bowing based on the grading system for anterolateral femoral bowing made by Park et al., with a lateral femoral bowing angle of 13.5  on the right and 16.9  on the left (Figure 1A and 1B). The standing anatomical femorotibial angle (FTA) measured 181.2  on the right and 181.6  on the left, suggesting a varus alignment (Figure 1C). Varus femoral neck-shaft angles (FSA) measuring 125.3  on the right and 127.5  on the left were also seen (Figure 1D).
case_images: Radiographs of bilateral femurs on admission in 2019. (A) A complete, non-comminuted transverse fracture of the mid right femoral shaft with medial spike (black arrow), consistent with a right complete AFF; and a faint transverse lucent line below indicative of incomplete AFF (white arrow). (B) Left incomplete AFFs (white arrows) with periosteal cortical thickening and multiple intracortical transverse fracture lines.
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case_images: Radiographs and Magnetic resonance imaging (MRI) during follow-up visits in 2020 and 2022. (A) Radiograph of right femur at 10 months (2020) after surgery showing callus formation, progressive healing of right mid-shaft AFF (black arrow) and stable alignment of the IMN. (B) Radiograph of left femur taken in 2022 showed persistence of the transverse lucent lines and thickened lateral cortex (white arrows), suggestive of persistent incomplete AFFs. (C) Turbo spin-echo proton-density weighted (TSE PD) MRI of left thigh showing chronic periosteal thickening and cortical sclerosis of the lateral aspects of the distal femoral shaft while (D) Turbo inversion recovery magnitude (TIRM) MRI shows irregular intramedullary high fluid signal of the distal left femoral shaft adjacent to the area of chronic cortical sclerosis, likely reflecting areas of bone marrow oedema secondary to reparative process from atypical cortical stress fractures.
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case_images: PMC10692435_01_JAFES-38-2-135-g003.jpg
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case_images: Follow-up imaging showed stable alignment of the IMN and progressive healing of the right AFF (Figure 3A). In 2022, 4 years since her first consult, the latest radiographs done showed non-healing lucent lines on the left femur (Figure 3B). Magnetic resonance imaging (MRI) of the left thigh (Figures 3C and D) showed chronic periosteal thickening and sclerosis of the lateral aspects of the distal femoral shaft with areas of serous marrow atrophy, likely secondary to the reparative process from cortical stress fractures.