ObjectiveTo design the channels of parallel screws and cross screws for fixation of symphysis pubis diastasis through a small sample anatomic study on pubic symphysis and its neighbor structures so as to provide anatomical basis for minimally invasive fixation of symphysis pubis diastasis. MethodsEight cadaveric pelvic specimens (6 men and 2 women) were transected along L5 and the proximal 1/3 of bilateral thighs, with intact lumbar spines. The spermatic cord, womb round ligament, and corona mortis were dissected; the distance to the ipsilateral pubic tubercle was measured and subsequently the distance between pubic tubercles, the height of pubic symphysis, the diameter of outer edge of pubic tubercle, the thickness of pubic symphysis and 2 cm outside the pubic symphysis (upper, central, and lower 1/3 thickness of pubic symphysis) were measured to provide anatomical basis for the design of channels of parallel screws and cross screws. ResultsParallel screw fixation: the entry point of first screw was on the outer edge of pubic tubercle, and its exit point was on the outer edge of contralateral pubic tubercle; a cannulated screw with a diameter of 4.5 mm or 6.5 mm can be suitable for this channel. The entry point of second screw was 20 mm outside the pubic symphysis and 23 mm beneath the pubic symphysis, and its exit point was symmetrical with entry point; a cannulated screw with a diameter of 4.5 mm can be appropriate for the second channel. The direction of two screws was perpendicular to the pubic symphysis. Cross screw fixation: the entry point of cross screws was on one side of the pubic tubercle, and its exit point was 20 mm outside the contralateral pubic symphysis and 23 mm beneath the contralateral pubic symphysis; two cannulated screws with a diameter of 4.5 mm can be chosen for cross screws channels. The direction of two cross screws was intersected with the horizontal line of two pubic tubercles at an angle of 25° respectively; besides, two cross screws formed an anteversion angle and retroversion angle of 5-10° with pubic body plane, respectively. ConclusionThe channels of parallel screws and cross screws are feasible for fixation of symphysis pubis diastasis by analyzing the anatomical data of the pubic symphysis and its neighbor structures, but further biomechanical research is need to confirm the stability of two fixation methods.
Objective To compare the clinical effects of traditional manual and robot-assisted implantation of cannulated screws in the treatment of femoral neck fracture. Methods The medical records of patients with femoral neck fracture in Department of Orthopaedics, People’s Hospital of Deyang City were analyzed retrospectively. The patients were divided into two groups, including the traditional manual implantation group from January to December 2018 and the robot-assisted implantation group from May 2019 to May 2020. The clinical therapeutic efficacy of the two groups were compared. Harris hip function score was used to evaluate hip function. Results A total of 85 patients were included. All patients had closed fractures. There were 45 cases in the traditional manual implantation group and 40 cases in the robot-assisted implantation group. There was no significant difference between the two groups in preoperative waiting time, operation time, hospitalization time, fracture healing time, complications within one year after operation, or Harris hip function score one year after operation (P>0.05). The placement nail time [(11.1±2.0) vs. (23.8±2.3) min; t=27.142, P<0.001], frequency of guide pin insertion [(4.7±1.2) vs. (11.4±1.7) times; t=20.640, P<0.001], frequency of intraoperative fluoroscopy [(10.8±1.7) vs. (21.0±1.8) times; t=26.990, P<0.001] and intraoperative blood loss [(8.1±2.0) vs. (12.0±1.7) mL; t=9.711, P<0.001] in the robot-assisted implantation group were less than those in the traditional manual implantation group. No wound infection or neurovascular injury was found in the two groups. Conclusion Robot-assisted implantation of cannulated screws in the treatment of femoral neck fracture has the advantages of less fluoroscopy, fewer guide pin insertion, less blood loss, more accurate screw placement than the traditional manual implantation of cannulated screws.