Percutaneous Cerclage Wiring Combined with Cephalomedullary Nailing for Irreducible Subtrochanteric Fractures

Intramedullary nailing for irreducible spiral subtrochanteric fractures: A comparison of cerclage and non-cerclage wiring

PURPOSE

Intramedullary nailing is the preferred internal fixation technique for the treatment of subtrochanteric fractures because of its biomechanical advantages. However, no definitive conclusion has been reached regarding whether combined cable cerclage is required during intramedullary nailing treatment. This study is performed to compare the clinical effects of intramedullary nailing with cerclage and non-cerclage wiring in the treatment of irreducible spiral subtrochanteric fractures.

METHODS

Patients with subtrochanteric fractures admitted to our center from January 2013 to December 2021 were retrospectively analyzed. The patients were enrolled in the case-control study according to the inclusion and exclusion criteria and divided into the non-cerclage group and the cerclage group. The patients' clinical data, including the operative time, intraoperative blood loss, hospital stay, reoperation rate, fracture union time, and Harris hip score, were compared between these 2 groups. Categorical variables were compared using Chi-square or Fisher's exact test. Continuous variables with normal distribution were presented as mean ± standard deviation and analyzed with Student's t-test. Non-normally distributed variables were expressed as median (Q1, Q3) and assessed using the Mann-Whitney test. A p < 0.05 was considered significant.

RESULTS

In total, 69 patients were included in the study (35 patients in the non-cerclage group and 34 patients in the cerclage group). The baseline data of the 2 groups were comparable. There were no significant difference in the length of hospital stay (z = -0.391, p = 0.696), operative time (z = -1.289, p = 0.197), or intraoperative blood loss (z = -1.321, p = 0.186). However, compared with non-cerclage group, the fracture union time was shorter (z = -5.587, p < 0.001), the rate of nonunion was lower (χ2 = 6.030, p = 0.03), the anatomical reduction rate was higher (χ2 = 5.449, p = 0.03), and the Harris hip score was higher (z = -2.99, p = 0.003) in the cerclage group, all with statistically significant differences.

CONCLUSIONS

Intramedullary nailing combined with cable cerclage wiring is a safe and reliable technique for the treatment of irreducible subtrochanteric fractures. This technique can improve the reduction effect, increase the stability of fracture fixation, shorten the fracture union time, reduce the occurrence of nonunion, and contribute to the recovery of hip joint function.

Biomechanical evaluation of three implants for treating unstable femoral intertrochanteric fractures: finite element analysis in axial, bending and torsion loads

Purpose: How to effectively enhance the mechanical stability of intramedullary implants for unstable femoral intertrochanteric fractures (UFIFs) is challenging. The authors developed a new implant for managing such patients. Our aim was to enhance the whole mechanical stability of internal devices through increasing antirotation and medial support. We expected to reduce stress concentration in implants. Each implant was compared to proximal femoral nail antirotation (PFNA) via finite element method. Methods: Adult AO/OTA 31-A2.3 fracture models were constructed, and then the new intramedullary system (NIS), PFNA, InterTan nail models were assembled. We simulated three different kinds of load cases, including axial, bending, and torsion loads. For further comparison of PFNA and the NIS, finite element analysis (FEA) was repeated for five times under axial loads of 2100 N. Two types of displacement and stress distribution were assessed. Results: Findings showed that the NIS had the best mechanical stability under axial, bending, and torsion load conditions compared to PFNA and InterTan. It could be seen that the NIS displayed the best properties with respect to maximal displacement while PFNA showed the worst properties for the same parameter in axial loads of 2100 N. In terms of maximal stress, also the NIS exhibited the best properties while PFNA showed the worst properties in axial loads of 2100 N. For bending and torsion load cases, it displayed a similar trend with that of axial loads. Moreover, under axial loads of 2100 N, the difference between the PFNA group and the NIS group was statistically significant (p < 0.05). Conclusion: The new intramedullary system exhibited more uniform stress distribution and better biomechanical properties compared to the PFNA and InterTan. This might provide a new and efficacious device for managing unstable femoral intertrochanteric fractures.

Finite-Element Analysis of a Novel Cephalomedullary Nail for Restricted Sliding to Reduce Risk of Implant Failure in Unstable Intertrochanteric Fractures

Objective

How to restrict sliding of cephalomedullary nail and rigid reconstruct medial support for unstable intertrochanteric fractures remains a challenge. This study aims to explore the feasibility of a novel cephalomedullary nail for restriction sliding and reconstruction of medial femoral support to prevent failure in unstable trochanteric fractures through finite element analysis.

Methods

The DICOM files of a unilateral femur spiral computed tomography (CT) scans from a elderly female were converted into STL files, and the most common clinical trochanteric fracture model with the absence of medial support, AO/OTA 31‐A2.3 was simulated by removing the posterior medial femur. The model of a novel medial sustain nail (MSN‐II) and a widely used nail (proximal femoral nail anti‐rotation PFNA‐II) were modeled according to the manufacturer‐provided engineering drawing. Different loads were applied to the femoral head to simulate the postoperative weight bearing gait. The sliding distance of helical blade in femoral neck, maximum stress of femur and nail, displacement of proximal fragment were analyzed to revealing the mechanical stability of unstable trochanteric fracture stabilized by different implant.

Results

The sliding distance of helical blade in the femoral neck, the maximum stress on the femur and nail, the displacement of proximal fragment in MSN‐II under 2100N axial load were 0.65 mm, 689 MPa, 1271 MPa, 16.84 mm respectively, while that were 1.43 mm, 720.8 MPa, 1444 MPa, 18.18 mm, respectively in PFNA‐II. The difference between the two groups was statistically significant (P < 0.05) and the stress was mainly distributed in medial distal side of nail but helical blade and the proximal aperture for the nail in MSN‐II. Compared to PFNA‐II, MSN‐II demonstrates biomechanical merit against femur medialization, cut‐out and coax varus.

Conclusion

The sliding distance of helical blade in femoral neck, the maximum stress on the femur and nail, and the displacement of proximal fragment of MSN‐II were less than those of PFNA‐II in the treatment of unstable intertrochanteric fractures. Therefore MSN‐II has better stability than PFNA‐II and it may have the potential to avoid femur medialization and cut out. It might be an option in unstable trochanteric fracture because of its superiority in restricted sliding and medial support reconstruction.