Fixation of femoral neck fracture with femoral neck system: a retrospective cohort study of 43 patients.

Backgrounds: This study aimed to analyze the clinical outcomes of femoral neck fractures (FNF) in patients treated with a femoral neck system (FNS, DePuy Synthes), which is a recently introduced device.

Methods: This retrospective cohort study of 43 patients who underwent osteosynthesis using FNS for FNF between July 2019 and June 2021 with a minimum follow-up of 6 months. The researchers examined the patients' demographic factors and radiologically evaluated the fracture type and fixation status, bone union, and postoperative complications.

Results: Of 43 patients, 25 were female, and the patients' mean age and body mass index were 62.1 years and 22.5 kg/m, respectively. According to the Association of Osteosynthesis/Orthopaedic Trauma Association (AO/OTA) classification, the most common fracture types were 31B1.1 and B1.2 (13 cases each), followed by B2.3, B2.1, and B2.2 (seven, five, and four cases, respectively). Radiological bone union was confirmed in 39 patients (90.7%), and the mean time to union was 3.6 months. Two cases of nonunion, one case of lag screw cut-out, and one case of osteonecrosis were confirmed; all four cases later underwent arthroplasty. The mean time to reoperation was 4.5 months. Meanwhile, five patients underwent implant removal after the bone union, and distal locking screw stripping was noted in three patients. All three patients required metal plate cutting to remove the implants.

Conclusions: Osteosynthesis of FNF using the newly introduced FNS showed favorable clinical outcomes and no specific hardware-related complications were reported during the follow-up. However, attention must be paid to the issue regarding distal locking screw failure during hardware removal.