Objective:To compare the efficacy of femoral neck system (FNS) and cannulated compression screw (CCS) in the treatment of femoral neck fracture in the young and middle-aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 91 patients with femoral neck fracture admitted to Fuzhou Second Hospital from July 2020 to December 2021, including 52 males and 39 females; aged 23-65 years [(48.9±10.3)years]. Garden classification of the fracture found that 31 patients were with type I, 9 with type II, 12 with type III and 39 with type IV. Pauwels classification of the fracture found that 7 patients were with type I, 33 with type II and 51 with type III. A total of 53 patients were treated with FNS fixation (FNS group) and 38 patients with CCS fixation (CCS group). The operation time, intraoperative blood loss, Haidukewych fracture reduction quality, hospitalization time, Barthel index, fracture healing time, and weight-bearing time were compared between the two groups. The hip function was assessed by Harris hip score in both groups at postoperative 3 months, 6 months and 1 year and at the final follow-up. The incidences of postoperative complication and secondary surgery were also compared between the two groups.Results:All the patients were followed up for 15-31 months [(22.2±5.5)months]. There were no significant differences in the operation time, Haidukewych fracture reduction quality, hospitalization time, or Barthel index (all P>0.05). The intraoperative blood loss in the FNS group was 50.0(20.0,85.0)ml, which was more than that in the CCS group [20.0(10.0,50.0)ml] ( P<0.01). The fracture healing time, partial weight-bearing time, and full weight-bearing time in the FNS group [4.0(3.0,5.0)months, 3.0(2.0,3.0)months, 5.0(4.5,6.0)months] were shorter than those in the CCS group [6.0(5.0,7.0)months, 3.0(2.8,4.0)months, 6.0(6.0,7.0)months] (all P<0.01). The Harris hip score at postoperative 3 months, 6 months and 1 year and at the final follow-up were 74.0(71.0,77.0)points, 87.0(84.0,88.5)points, 91.0(88.0,95.0)points, and 94.0(91.0,96.0)points in the FNS group, significantly higher than those in the CCS group [73.0(70.0,74.0)points, 82.5(79.8,87.0)points, 88.0(83.5,91.0)points, 89.0(84.0,93.0)points] (all P<0.05 or 0.01). There were no statistically significant differences in the incidences of postoperative complication or secondary surgery between the two groups (all P>0.05). Conclusion:Compared with CCS, FNS can shorten fracture healing time, allow patients to carry full weight as soon as possible, and significantly improve hip function in the treatment of middle-aged and young adults with femoral neck fracture, although there is more intraoperative blood loss.

Objective:To investigate the incidence of and risk factors for femoral neck shortening in young and middle-aged patients with displaced femoral neck fracture treated by a femoral neck system (FNS).Methods:A retrospective study was conducted to analyze the clinical data of 135 patients with displaced femoral neck fracture who had been treated by closed reduction and FNS internal fixation at Department of Orthopaedics, The Second Hospital of Fuzhou from December 2019 to December 2021. There were 85 males and 50 females, with an age of 51 (42, 57) years and a body mass index of 22.6 (20.9, 24.2) kg/m 2. According to the Garden classification, there were 29 cases of type Ⅲ and 106 cases of type Ⅳ. Femoral neck shortening was observed. The patients' gender, age, side of shortening, body mass index, fracture type, high-energy injury, time from injury to surgery, cortical comminution at the fracture end, reduction quality (Garden index), partial weight bearing time, complete weight bearing time, and functional evaluation (Harris score) were recorded for a univariate analysis. Multivariate logistic regression was used to analyze the influencing factors for moderate to severe shortening. Results:All the 135 patients were followed up for 17.2 (15.0, 20.2) months. Different degrees of femoral neck shortening happened in all patients, yielding an incidence of 100%(135/135). The femoral neck shortening was 4.2 (2.6, 7.7) mm in displaced femoral neck fractures fixated by FNS. The shortening continued to worsen within the first 3 months after operation, reaching a stable state in the first 6 months. Persistent shortening hardly occurred after 6 months. According to the shortening distance, the patients were divided into a mild shortening group (76 cases <5 mm) and a moderate to severe shortening group (59 cases ≥ 5 mm). The Harris score at the last follow-up in the mild shortening group (91.7 ± 2.3) was significantly higher than that in the moderate to severe shortening group (87.9 ± 3.8) ( P<0.001). The fracture healing rate was 98.7% (75/76) in the mild shortening group and 98.3% (58/59) in the moderate to severe shortening group, showing no significant difference ( P=1.000). Logistic regression analysis found that the risk factors for moderate to severe shortening were fracture type (type Ⅳ) ( OR = 10.227, 95% CI: 1.845 to 56.693, P = 0.008), cortical comminution at the fracture end (if present) ( OR=52.697, 95% CI: 9.870 to 281.352, P<0.001), and partial weight bearing time <4 weeks ( OR = 0.168, 95% CI: 0.032 to 0.893, P = 0.036). Conclusions:The incidence of femoral neck shortening may be high in young and middle-aged patients with displaced femoral neck fracture treated by FNS, leading to decreased hip function. The main risk factors for femoral neck shortening are fracture type (Garden type Ⅳ), cortical comminution at the fracture end and partial weight-bearing time less than 4 weeks.