Reduction of valgus-impacted femoral neck fractures by Schanz screw combined with rod stick technique / 中华骨科杂志

ABSTRACT

Objective:To investigate the clinical efficacy of the femoral neck system (FNS) after the reduction of the Schanz screw combined with the rod stick technique in the treatment of valgus-impacted femoral neck fracture.Methods:A retrospective analysis of clinical data from 66 patients with valgus-impacted femoral neck fractures from December 2019 to November 2021 has been performed. All patients were treated with the Femoral Neck System. Auxiliary reduction group (using the Schanz screw and rod stick technique), including 32 cases, 9 males and 23 females with an average age of 52.7±12.0 years (range, 28-77 years); 14 patients on the left side and 18 patients on the right side; body mass index 23.1±2.6 kg/m 2. Manual reduction group (using the traditional Flynn closed reduction technique), including 34 cases, 18 males and 16 females with an average age of 52.1±12.7 years (range, 26-75 years); 18 patients on the left side and 16 patients on the right side; body mass index 23.4±2.3 kg/m 2. The surgery time, intraoperative blood loss, complications, and Harris hip score at the last follow-up were collected and compared between the two groups. Preoperative and postoperative abduction angle and posterior tilt angle were measured in the anterior-posterior and lateral positions of the hip, as well as the length of the femoral neck shortening at the last follow-up. Pearson analysis was used to evaluate the correlation between preoperative and postoperative abduction angle and posterior tilt angle, the length of femoral neck shortening, and Harris hip score. Results:There were no significant differences in baseline data such as gender, age, side of injury, height, weight, and body mass index, and the surgery time and intraoperative blood loss between auxiliary reduction group and manual reduction group ( P>0.05). All 66 cases with a mean follow-up of 20.4 months (ranges 12-29 mouths). The fracture healing time was 5.0±0.9 weeks in the auxiliary reduction group and 4.9±0.8 weeks in the manual reduction group ( t=-0.41, P>0.05). There were no significant statistical difference in the preoperative abduction angle and preoperative posterior tilt angle between the auxiliary reduction group and the manual reduction group ( P>0.05). The postoperative abduction angle and posterior tilt angle of the auxiliary reduction group (1.8°±3.1°, 1.2°±3.0°) were significantly lower than those of the manual reduction group (13.7°±6.5°, 6.8°±4.1°, t=-9.55, P<0.001; t=-7.42, P<0.001). Preoperatively, 61 cases (92%) were associated with a posterior tilt of the femoral head, and 30 (46%) of them had a posterior tilt angle of more than 10°. The length of femoral neck shortening at the last follow-up and the moderate and severe femoral neck shortening rate postoperatively in the auxiliary reduction group (1.4±2.1 mm, 0, and 3%) were significantly lower than those in the manual reduction group (8.1±4.8 mm, 38%, and 32%, P<0.05). Harris hip score at the last follow-up in the auxiliary reduction group 91.1±4.5 was significantly higher than those in the manual reduction group 85.5±5.4 ( t=4.54, P<0.001). The postoperative abduction angle and length of femoral neck shortening showed correlations with the Harris hip score respectively ( r=-0.551, -0.743; P<0.001). In the auxiliary reduction group, 1 case of broken temporary fixed Kirschner wire was removed by nucleus pulposus forceps, and the fracture site healed after surgery. In 2 cases, the Schanz screw loosened and pulled out during the reduction process, and the successful reduction was achieved after increasing the depth of the Schanz screw insertion, and no peri-Schanz screw fracture occurred. After surgery, 3 cases (1 case in the auxiliary reduction group and 2 cases in the manual reduction group) developed avascular necrosis of the femoral head (18 months, 18 months, and 2 years after surgery, respectively), femoral head collapse and severe shortening of the femoral neck, all of which underwent total hip arthroplasty. Conclusion:FNS after the reduction of the Schanz screw combined with the rod stick technique in the treatment of valgus-impacted femoral neck fracture has the advantages of effectively correcting preoperative abduction angle and posterior tilt angle and reducing the length of femoral neck shortening, and it can obtain satisfactory short and medium-term clinical efficacy.