What is the best method of fixation for minimally displaced subcapital neck of femur fractures? A systematic review

A Criterion of Reduction Quality of Femoral Neck Fractures Based on Spatial Residual Displacements of Femoral Head

OBJECTIVE

Currently, quality criteria for reduction after femoral neck fractures such as the Garden index are mainly based on two-dimensional x-rays. Research shows that current reduction quality criteria are no longer sufficient to meet the needs to reduce the incidence of osteonecrosis of the femoral head (ONFH). The purpose of this study is to construct a reduction quality criterion based on spatial residual displacements of 3D reconstruction and to predict the occurrence of ONFH.

METHODS

The subjects were from the Tianjin Hospital Hip Fracture cohort, all of whom experienced femoral neck fractures and underwent reduction and internal fixation at Tianjin Hospital and received 12 months of follow-up minimally postoperatively. CT scans were used for 3D reconstruction, and six spatial displacement indicators were measured. Risk factors of ONFH were identified using logistic regression, and a reduction quality criterion based on spatial residual displacements was constructed. Multivariate logistic regression models were performed to estimate the effect of reduction quality by the new criterion on ONFH.

RESULTS

Data from 391 patients were included in the final analysis. Preoperative displacement of the center of the femoral head (CFH), postoperative residual displacement of the CFH, and residual rotational displacement were proved to be independent risk factors for ONFH, with OR values of 3.83 (95% CI: 1.98, 7.48), 2.62 (95% CI: 1.05, 6.49), and 5.36 (95% CI: 2.46, 11.64), respectively. The new criterion was composed of two indicators and had three grades: when residual displacement of CFH is ≤ 4.075 mm, and residual rotational displacement of femoral head is ≤ 18.595°, the quality is excellent; when residual displacement of CFH is ≤ 4.075 mm and residual rotational displacement of femoral head is > 18.595° or when residual displacement of CFH is > 4.075 mm and residual rotational displacement of femoral head is ≤ 18.595°, the quality is moderate; when residual displacement of CFH is > 4.075 mm and residual rotational displacement is > 18.595°, the quality is poor. The risk of ONFH would increase 3.99 times (95% CI: 2.35, 6.78) for each lower grade in reduction quality. The logistic regression model was well discriminated with an AUC area of 0.802 and had good calibration with a p-value of > 0.05 by the Hosmer-Lemeshow test.

CONCLUSION

A new reduction quality criterion for femoral neck fracture based on CT was constructed, and reduction quality before fixation by the new criterion was proved to be an independent predictive factor for ONFH. The logistic regression model had quite good discrimination and calibration for postoperative ONFH.

A recent update on the fixation techniques for femoral neck fractures: A narrative review

Femoral neck fractures present significant challenges in orthopedic surgery, particularly due to technical difficulties and a high complication rate. Surgical intervention is generally recommended, with osteosynthesis and arthroplasty being the main treatment options. Osteosynthesis techniques, including dynamic hip screw (DHS), multiple cannulated screws (MCS), and the femoral neck system (FNS), aim to achieve stable fixation and facilitate fracture healing. Factors influencing the choice of osteosynthesis include fracture displacement, bone quality, patient age, and the presence of posterior tilt. While DHS offers high stability, MCS is preferred in stable type fractures with minimal invasive procedures. FNS, a newer technique, combines the advantages of DHS and MCS, providing strong fixation with minimal soft tissue damage. Considering the comprehensive findings of biomechanical and clinical studies to date, when performing osteosynthesis for unstable femoral neck fractures, caution should be exercised with MCS as it may have slightly inadequate fixation strength compared to DHS and FNS. FNS, being the newest technique, demonstrates superior fixation strength comparable to DHS and is as minimally invasive as MCS. However, it is essential to remember that long-term follow-up results are lacking for FNS.

[Treatment of proximal femoral fractures : Principles, tips and tricks]

Proximal femoral fractures occur at an annual incidence of approximately 200/100,000 inhabitants and mortality rates range up to 30% especially in geriatric patients where complications are not necessarily associated to surgery. In nearly all cases surgical treatment is required. Procedures to preserve the femoral head have to be performed as early as possible (as specified by the Federal Joint Committee, GBA, within 24 h). For joint-preserving approaches in medial femoral neck fractures a time to surgery within 6 h is considered to be advantageous. Perioperative patient care is of high importance regarding the prevention of pneumonia, renal failure, delirium and further complications. Postoperatively full weight bearing enables for early mobilization and prevention of surgery-related complications. Nonunions, avascular necrosis of the femoral head, cut-out and prosthetic dislocation must be avoided by the selection of the appropriate procedure. Minimally displaced femoral neck fractures are primarily treated by osteosynthesis and conservative management is only considered in isolated cases. For displaced femoral neck fractures, factors such as a young biological age with high activity levels, the absence of arthritis and good bone quality with a successful reduction favor for a femoral head-preserving osteosynthesis. Otherwise, (hybrid) total hip replacement (THR) is the preferred method for unstable and displaced fractures, whereby hemiarthroplasty should only be considered for very old and patients with pre-existing diseases. Fractures in the trochanteric region are treated with a proximal femoral nail and subtrochanteric fractures are managed using a long proximal femoral nail. To avoid secondary complications, the choice of optimal treatment should be based on a good understanding of the injury pattern, biomechanical and technical aspects of each procedure.