To explore the correlation between the postoperative clinical efficacy of femoral neck system (FNS) in the treatment of femoral neck fractures and the position of internal fixation.

Sixty patients with Garden type Ⅳ femoral neck fracture treated with FNS in the Department of Orthopedics, Suzhou Municipal Hospital from January 2019 to April 2022 were included and were followed up completely. The imaging data of all patients were analyzed retrospectively. Postoperative CT and X-ray imaging were used to measure and calculate the deviation degree of the end of the FNS screw bolt relative to the central axis of the femoral head and neck and the tip-apex distance (TAD). All patients were followed up for at least 1 year. At the last follow-up, pelvic X-ray imaging was used to measure the femoral neck shortening length, and Harris hip score was used to evaluate the postoperative clinical efficacy. The correlation between the deviation degree of FNS screw bolt and TAD, femoral neck shortening length and Harris hip score at the last follow-up were analyzed.

All patients were followed up for (20.55±5.89) months. There were 27 males and 33 females, with a mean age of (45.48±10.09) years. Both TAD (r=0.327, P<0.05) and femoral neck shortening length at the last follow-up (r=0.310, P<0.05) were significantly positively correlated with the deviation + degree of the end of the FNS screw bolt relative to the central axis of the femoral head and neck. The Harris hip score at the last follow-up was significantly negatively correlated with the deviation of the end of the FNS screw bolt relative to the central axis of the femoral head and neck (r=-0.275, P<0.05). Femoral neck shortening length at the last follow-up was significantly positively correlated with TAD (r=0.278, P<0.05). The Harris hip score at the last follow-up was significantly negatively correlated with TAD (r=-0.314, P<0.05) and femoral neck shortening length at the last follow-up (r=-0.282, P<0.05).

In the treatment of femoral neck fractures with femoral neck system, the FNS screw bolt is placed as close as possible to the central axis of the femoral head and neck with appropriate TAD, which is more likely to achieve better clinical efficacy.