case_images: PMC11291235_01
case_images: Ultrasonographic images of the healthy right (A) and affected left hip joints (B,C). (A) Echogenic lines of the femoral neck (FN) and the acetabulum (Ac) are evident at a deeper site than the pelvic muscular layers comprising of the superficial gluteus muscle (SG), the middle gluteal muscle (MG), and the deep gluteal muscle (DG). (B) When scanning near the pelvis, the 5-10-mm-thick wall of the capsule (Cp) encloses the fluidity materials with a mixture of hyper- and hypo-echogenicity. (C) When scanning around the area of the femur, the round, echogenic surface of the femoral head (FH) and femoral neck (FN) are evident within the capsular lesion including the fluidity materials (asterisk).
case_images: fvets-11-1292924-g001.jpg
case_images: PMC11291235_01_fvets-11-1292924-g001.jpg
case_images: fig1
case_images: Ultrasonography of the right hip joint revealed normal appearance of the smooth echogenic line of the femoral neck and the echogenic line of the acetabulum (Figure 1A). On the ultrasonogram of the left hip joint, 5-10-mm-thick capsular structures were present in the region 1-2 cm deeper than the skin surface and across the anatomical level between the pelvis and femoral head (Figures 1B,C). Histology of the removed femoral head and acetabulum revealed common findings such as aggregation of inflammatory cells and fibroblasts together with scattered formation of small abscess foci in the bone marrow tissues, osteolytic and necrotic changes in the cancellous bone layers, and infiltration of neutrophils and bacterial colonization in the bone cortex layers (Supplementary Figures S1, S2).
case_images: Ventral-dorsal pelvic radiographs and three-dimensional computed tomographic images of the dorsal skeletal views of the pelvis taken at admission (A,B, respectively) and soon after surgery (C,D, respectively). (A) An irregular, radiolucent femoral head (arrow) is evident within the swollen hip joint. (B) Small bone fragments are present within the extended gap between the transformed femoral head (arrow) and the irregular surface of the acetabulum. (C) The irregular cut surface of the femur penetrates the irregular cup of the acetabulum. (D) The cut surface of the femoral neck is located almost inside the irregular cup of the acetabulum. Arrowhead: a Penrose drain. Scale: 25 mm.
case_images: fvets-11-1292924-g002.jpg
case_images: PMC11291235_01_fvets-11-1292924-g002.jpg
case_images: fig2
case_images: VD radiographs with the animal's hind limb in the supine position revealed that the articular gap between the acetabulum and the femoral head was extended (Figure 2A). Tokyo, Japan). A 3D CT image of the dorsal side of the pelvis showed that the femoral head had an irregular and transformed surface on the left hind limb (Figure 2B). An irregular cut surface was observed in the femoral neck on the VD radiograph obtained immediately after surgery (Figure 2C). Subsequent 3D CT revealed that the femoral head could be resected at the base level, while most of the femoral neck remained intact (Figure 2D). Histology of the removed femoral head and acetabulum revealed common findings such as aggregation of inflammatory cells and fibroblasts together with scattered formation of small abscess foci in the bone marrow tissues, osteolytic and necrotic changes in the cancellous bone layers, and infiltration of neutrophils and bacterial colonization in the bone cortex layers (Supplementary Figures S1, S2).
case_images: Transverse computed tomographic images taken at admission (A,B) and soon after surgery (C). (A) Small bone fragments are present between the heterogeneously hypoattenuating femoral head (FH, arrow) and the irregular surface of the acetabulum (Ac) within the extended, hypoattenuating capsular mass (asterisk). 1B and 1C show the scanning locations of Figures 1B,C, respectively. HN, femoral neck. (B) Accumulation of gas (arrowhead) is evident within the capsular mass (asterisk). (C) The gap between the irregular surfaces of the acetabulum and cut surface of the femur is narrower than those shown in (A). PD: a Penrose drain. Scale: 25 mm.
case_images: fvets-11-1292924-g003.jpg
case_images: PMC11291235_01_fvets-11-1292924-g003.jpg
case_images: fig3
case_images: Transverse CT showed that the hip joint lesion extended significantly in the circumferential direction from the central femoral head (Figure 3A). On transverse CT image slightly caudal to the section shown in Figure 3A, a crescentic accumulation of air was evident along the ventral margin of the lesion because the air moved to the upper side of the lesion when examined in a supine position (Figure 3B). On postoperative transverse CT, small amounts of exudate were present, together with scattered air accumulation within the narrow space between the irregular surface of the acetabulum and the cut surface of the femoral neck (Figure 3C). The histology of the removed lesion walls revealed predominant proliferation of collagen fibers and granulation tissue (Supplementary Figure S3).
case_images: Intraoperative photos of femoral head ostectomy for septic arthritis of the hip joints together with osteomyelitis of the femoral head (A-C) and macroscopic views of the resected femoral head (D,E). (A) A small cut is made on the surface of the capsular mass extending into the entire area deeper than the transected middle gluteal muscle. (B) The surface of the femoral head (asterisk) is partially evident inside the lesion's cavity filled with granulation tissue. (C) Resection is made using a bone chisel applied to the area of the femoral neck at the farthest point possible to the side of the femoral head (asterisk). (D) An ulcerative lesion (arrow) is evident on the articular surface of the resected femoral head. (E) Discoloration is evident in the cut surface of the resected femoral head.
case_images: fvets-11-1292924-g004.jpg
case_images: PMC11291235_01_fvets-11-1292924-g004.jpg
case_images: fig4
case_images: The surface of the lesion was exposed in the entire region distal to the transected middle gluteal muscle (Figure 4A). After removing the caseating tissue, the femoral head was identified on the far side of the cavity (Figure 4B). The femoral head was removed by resecting the area of the femoral neck using a bone chisel (Figure 4C). An ulcerative lesion was macroscopically evident near the resected area of the articular surface of the femoral head (Figure 4D). Discoloration and structural fragility were further observed on the cut surface of the femoral head (Figure 4E).