Femoral neck system versus cannulated screws with a medial plate for the fixation of Pauwels type III femoral neck fractures in young patients: a retrospective cohort study

The purpose of this study was to compare the efficacy of femoral neck system (FNS) and cannulated screws with a medial plate (CSMP) for Pauwels type III femoral neck fractures in young adults. In this retrospective analysis, 70 patients aged 18–65 with Pauwels type III femoral neck fractures were divided into two groups according to internal fixation: 37 in the FNS group and 33 in the CSMP group. Postoperative complications and functional outcomes were mainly studied. The mean follow-up was 25.3 ± 3.7 months. The FNS group exhibited significantly shorter fluoroscopy time, less blood loss, and shorter surgical time than the CSMP group (all P < 0.001). The CSMP group had a shorter fracture union time than the FNS group (P = 0.032). The length of femoral neck shortening at 6-, 12-, and 18-months was significantly lower in the CSMP group (all P < 0.05). Harris Hip Score (HHS) at 6 months was higher in the CSMP group (P = 0.042). However, no significant differences were observed between the two groups regarding the length of femoral neck shortening at 3 months or Harris Hip Score (HHS) at 3-, 12-, and 18 months (all P > 0.05). The VAS scores at 18 months showed no significant difference between the two groups (P = 0.247). Additionally, no significant differences were noted in other complications. There is a significant difference in the Harris Hip Score at 18 months between the femoral neck shortening and the non-shortening groups (P < 0.001). Logistic regression analysis identified fracture comminution (OR = 7.764, 95% CI 1.928–31.258) as a risk factor for developing femoral neck shortening. FNS and CSMP demonstrated similar long-term functional outcomes and complication rates in young patients with Pauwels type III femoral neck fractures. CSMP was superior in promoting bone healing and minimizing femoral neck shortening. More significant femoral neck shortening was correlated with inferior hip functional outcomes. Fracture comminution posed a risk for the development of femoral neck shortening in these cases.