FNS implant a minimally invasive alternative to DHS in treatment of femur neck fractures

Amit Davidson et al study showed that FNS is a safe treatment option for femoral neck fractures (FNF). Intra-operative parameters and failure rates are comparable to other frequently used implants. The study has been published in "International Orthopaedics" journal.

The recently developed femoral neck system (FNS) (DePuy Synthes, Raynham, MA, USA) for treatment of femoral neck fractures (FNF), comprises theoretical biomechanical advantages of combining compression and anti-rotation qualities during internal fixation. The effective solution the FNS design provides, involves the screw-plate construct, allowing stronger fixation, as well as a combination of blade and anti-rotation screw, that improves axial and rotational stability. Biomechanical studies have shown axial and rotational stability superiority of FNS implant over the traditional cannulated screws (CS) and the dynamic hip screw (DHS).

Amit Davidson et al conducted a retrospective multicentric analysis of patients treated by FNS with a minimum of three months of follow-up. Details analysed from three medical centres were operative duration, estimated blood loss, initial hospitalisation duration, fixation quality as well as complications and reoperation rate. Patients who had revision surgery were compared to all other patients to identify risk factors for failure. In addition, a literature review was performed to analyse data on FNS clinical implementation and patient's outcomes. The two data sets were combined and analysed.

The results of the study were:

• One-hundred and two patients were included in this study cohort with an average follow-up of seven months (range 3–27).

• Ten papers were included in the literature review, reporting data on 278 patients. Overall, 380 patients were analysed.

• Average age was 62.6 years, 52% of the fractures were classified as Gardens 1–2.

• The average estimate blood loss for the FNS procedure was 47 (ml), an estimate, which is in the lower reported range for similar procedures.

• The average operative time was 44 (range 21–95) minutes. The reported short operative time can be attributed to the low number of surgical steps in FNS which enhances procedural efficiency.

• Overall, the revision rate was 9.2% (14 patients diagnosed with cut-out of implant, 10 with AVN, 8 with non-union and 8 with hardware removal).

• For the 102 patients in the cohort risk factors for reoperation included patients' age, surgeon seniority and inadequate placement of the implant.

Further reading:

Neck of femur fractures treated with the femoral neck system: outcomes of one hundred and two patients and literature review

Amit Davidson et al

International Orthopaedics (2022) 46:2105–2115

https://doi.org/10.1007/s00264-022-05414-0