Objective To observe the complication after embolizing the bilateral internal il iac arteries and the median sacral artery of dogs by different combinations and embolization levels with gelfoam particle, and to provide a reference for safety appl ication of gelfoam in cl inic. Methods Sixteen common grade adult healthy dogs (weighing 10-13 kg, 14 males and 2females) were randomly divided into 5 groups. Under the monitoring of digital subtraction angiography (DSA), the embolization was performed with gelfoam particle (diameter, 50-150 μm) in bilateral internal il iac arteries and the main branch of the median sacral artery (group A, n=3), in bilateral internal il iac arteries and the first branch of the median sacral artery (group B, n=3), in the main branch of bilateral internal il iac arteries (group C, n=3), in the unilateral internal il iac artery and the main branch of the median sacral artery (group D, n=4), and in the main branch of unilateral internal il iac artery (group E, n=3). Under the DSA, the anatomic relationships of the abdominal aorta, bilateral external il iac arteries, bilateral internal il iac arteries, and median sacral artery were observed before embol ization. The survival dogs were observed and the specimens of bladder, rectum, sciatic nerve, and gluteal muscles were harvested for the general and histological observations at 3 days after embolization. Results In dogs, there was no common il iac artery; bilateral external il iac arteries originated from the abdominal aorta and the starting of the median sacral artery had variation. Seven dogs (3 in group A, 3 in group C, and 1 in group D) died within 2 days after embolization, and the others survived to the end of the experiment. In the dead dogs of groups A, C, and D, the darkening and necrosis of the rectum were observed; the bladder presented lamellar obfuscation and focal hemorrhage and edema; and the median urinary volume in bladder was 270.6 mL. In survival dogs, no obvious change was observed in the rectum; the bladder only manifested l ight edema; and the median urinary volume in bladder was 137.0, 220.5, and 28.0 mL, respectively in groups B, D, and E.The rectum and bladder of dead dogs in groups A, C, and D manifested the disrupted cells, generous inflammatory cells infiltration, and desquamation of epithel ial cells; the rectum and bladder of survival dogs in groups B, D, and E manifested l ight inflammatory cells infiltration and edema; the embol ized artery mainly focused on the arterioles whose diameter was 100-200 μm. The sciatic nerve and gluteal muscles of each group had no obvious change except for l ight edema. Conclusion When the internal il iac artery and median sacral artery are embol ized with gelfoam particle with a diameter of 50-150 μm, to ensure the safeness of pelvic organs, the embol ized artery can not exceed the first branch when the 3 arteries are embol ized at the same time, or reserve at least unilateral internal il iac artery when embol ized to the trunk , or it will result in pelvic organ necrosis and perforation.
Objective To investigate the reliability of determining rotational positioning of femoral prosthesis using the coronal transverse tibial axis at 90° of knee flexion as the reference in total knee arthroplasty (TKA). Methods Fifty-five patients with knee osteoarthritis undergoing TKA between November 2020 and February 2026 who met the selection criteria were enrolled. There were 14 males and 41 females, aged 54-82 years, with a mean age of 66.4 years. Preoperative knee CT and full-length lower-extremity X-ray films were performed to measure the hip-knee-ankle angle (HKA) and posterior condylar angle (PCA). During surgery, after distal femoral osteotomy, the knee was maintained at 90° of flexion, and the tibial transverse axis (line a) perpendicular to the coronal projection of the tibial mechanical axis was marked on the osteotomy surface. Following tibial osteotomy and gap balancing, the external rotation line of the femoral component (line b) was determined. The final external rotation osteotomy angle was established based on the above references, and four-in-one positioning pins were fixed according to this angle. The line connecting the positioning pins served as the known external rotation reference line (line r). Accordingly, the external rotation angles of Line a and Line b relative to the posterior condylar line of the femur (∠A, ∠B) were calculated separately. The differences among PCA, ∠A, and ∠B were compared, and the correlation between ∠A and ∠B,∠A and HKA were analyzed. In addition, the distribution of ∠A in and around the “safe zone” (between PCA and ∠B) was counted. Results Preoperative HKA was (7.3±3.7)°, and PCA, ∠A, and ∠B were (3.1±1.4)°, (4.6±2.4)°, and (4.7±2.1)°, respectively. Compared with PCA, both ∠A and ∠B demonstrated greater external rotation, with significant differences (P<0.05); no significant difference was found between ∠A and ∠B (P>0.05). Correlation analysis revealed significant correlations between ∠A and ∠B, as well as between ∠A and HKA (r=0.674, P<0.001; r=0.350, P=0.009). In 45% (25/55) of patients, ∠A was between PCA and ∠B, which was within the “safe zone”. Conclusion The transverse tibial axis at 90° of knee flexion during TKA serves as a reliable reference for determining rotational positioning of femoral prosthesis. The severity of preoperative knee varus deformity correlates with the external rotation angle defined by this transverse tibial axis, and this angle shows high consistency with that derived from the gap balancing technique.
