Biomechanical stability of short versus long proximal femoral nails in osteoporotic subtrochanteric A3 reverse-oblique femoral fractures: a cadaveric study

Peri-implant fractures after Intramedullary fixation for femoral trochanteric fracture: a multicenter (TRON Group) study

BACKGROUND

With the rise in elderly populations, the incidence of femoral trochanteric fractures has also increased. Although intramedullary nail therapy is commonly used, the incidence of peri-implant fractures (PIFs) as a complication and its associated factors are not fully understood. The purpose of this study was to determine the incidence of PIFs and treatment strategies and outcomes.

METHODS

A retrospective study across 11 hospitals from 2016 to 2020 examined 1855 patients with femoral trochanter fracture. After excluding 69 patients treated without intramedullary nailing, 1786 patients were analyzed. Parameters studied included age, sex, body mass index, medical history, and treatment methods. PIFs were categorized using the Chan classification. Treatment outcomes and patient mobility were assessed using the Parker Mobility Score, and postoperative complications and one-year survival data were compiled.

RESULTS

The incidence of PIFs was 8 in 1786 cases. Chan classification showed 1 case of N1A, 6 of N2A, and 1 of N2B. Only the type N1 case was a transverse fracture, whereas all cases of type N2 were oblique fractures. Among these cases, five patients had fractures extending to the upper part of the femoral condyle. The patient with N1A and one bedridden patient with N2A fracture underwent conservative treatment, one patient with N2A in which the fracture did not extend to the condyle was treated with nail replacement, and 5 patients (N2A: 4, N2B: 1) with fractures extending to the condyle were treated with additional plate fixation. All patients had survived at one year after treatment for PIF, and no reoperations were required.

CONCLUSIONS

The incidence of PIF was very low (0.45%). Of the 6 PIF cases, excluding the bedridden patients, the treatment of choice for PIF was an additional plate if the fracture line extended to the femoral condyle; otherwise, the nail was replaced. All patients achieved bony fusion.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Comparative study of a novel proximal femoral bionic nail and three conventional cephalomedullary nails for reverse obliquity intertrochanteric fractures: a finite element analysis

Purpose

Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed.

Methods

In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement.

Results

Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm).

Conclusion

Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.

What is the Optimal Nail Length to Treat Osteoporotic Subtrochanteric Fractures? A Finite Element Analysis

Background

Operative management with intramedullary nail fixation remains the definitive treatment of choice for osteoporotic subtrochanteric (ST) fractures; however, there remains no consensus regarding the proper nail length. We aimed to use 3-dimensional finite element (FE) analysis to determine the optimal nail length for the safe fixation of osteoporotic ST fractures.

Methods

Nine modes of FE models were constructed using 9 different lengths of cephalomedullary nails (short nails: 170, 180, and 200 mm; long nails: 280, 300, 320, 340, 360, and 380 mm) from the same company. The interfragmentary motion was analyzed. Additionally, the peak von Mises stress (PVMS) in the cortical bone, cancellous bone of the femoral head, and the nail were measured, and the yielding risk for each subject was investigated.

Results

Long nails were associated with less interfragmentary motion. In the cortical bone, the PVMS of short nails was observed at the distal locking screw holes of the femoral medial cortex; however, in long nails, the PVMS was observed at the lag screw holes on the lateral cortex. The mean yielding risk of long nails was 40.1% lower than that of short nails. For the cancellous bone of the femoral head, the PVMS in all 9 FE models was in the same area: at the apex of the femoral head. There was no difference in the yielding risk between short and long nails. For implants, the PVMS was at the distal locking screw hole of the nail body in the short nails and the nail body at the fracture level in the long nails. The mean yielding risk was 74.9% lower for long nails than that for short nails.

Conclusions

Compared to short nails, long nails with a length of 320 mm or more showed less interfragmentary motion and lower yielding risk in low-level osteoporotic ST fractures. The FE analysis supports long nails as a safer option than short nails, especially for treating transverse-type low-level osteoporotic ST fractures.

No difference in clinical and hospital quality outcomes in treatment of reverse obliquity intertrochanteric Hip fractures (AO/OTA 31.A3) based on Cephalomedullary nail length

INTRODUCTION

The purpose of this study was to evaluate outcomes following reverse obliquity (RO) intertrochanteric hip fractures based on the use of short cephalomedullary nails (CMNs) compared to long CMNs for fixation.

METHODS

An IRB-approved prospectively collected hip fracture registry at an urban academic medical center was queried for all AO/OTA 31A3.1-3 reverse obliquity intertrochanteric (RO) fractures. One hundred and seventy patients with age > 55 years old and minimum 6-month follow-up were identified for analysis. Data was collected for patient demographics, injury details, intraoperative radiographic parameters, perioperative physiologic parameters, hospital quality measures, and outcomes including radiographic time to healing, need for reoperation, nonunion, and mortality. Comparative analyses were conducted between cohorts. Additional multivariable binary logistic and linear regression analyses were performed to evaluate for factors independently associated with short and long nail usage.

RESULTS

The mean age of the entire cohort was 80.91±10.09 years: 103 patients had a long CMN implanted, and 67 patients had a short CMN implanted. There were no demographic differences or differences in radiographic time to healing, rates of mortality, readmission, nonunion, and need for reoperation. Univariable analysis revealed that short CMN had lower intraoperative blood loss (111.19±83.97 mL vs 176.72±161.45 mL, p = 0.002), decreased need for transfusion (37% vs. 55 %, p = 0.022), and shorter procedures (118.67±57.87 min vs. 148.95±77.83 min, p = 0.002. Multivariable analysis revealed that short nail usage was associated with decreased intraoperative blood loss, decreased need for transfusion, and shorter operative times.

CONCLUSION

Nail length does not affect healing or hospital quality outcomes in the treatment of RO hip fractures. The use of short CMNs for these fractures did correlate with lower intraoperative blood loss, operative time, and need for blood transfusion, with non-inferior outcomes and similar hospital quality measures when compared to long CMNs.

Failure of Fixation in Trochanteric Hip Fractures: Does Nail Design Matter?

OBJECTIVE

The objective of this study was to compare clinical outcomes of patients with trochanteric hip fractures treated with specific different cephalomedullary nail (CMN) designs.

METHODS

A scoping review of the English literature was performed. Inclusion criteria were studies comparing perioperative and postoperative outcomes of trochanteric hip fractures fixated by CMNs for one of the following CMN designs: short versus long nails, blade versus screw fixation, dual versus single lag screw fixation, and application of cement augmentation. Inclusion criteria consisted of human comparative clinical trials (randomized and observational). Exclusion criteria included noncomparative studies, studies comparing CMN with non-CMN devices or with arthroplasty, studies with less than 3 months follow-up, studies that did not provide relevant clinical outcome measures, biomechanical, finite element analyses, animal, or in vitro publications. Data regarding reoperations, peri-implant fractures, mechanical failure, nonunion, infection rates, and functional outcomes were reviewed.

RESULTS

Twenty-two studies met the inclusion criteria and formed the basis of this study. Failure of fixation rates and reoperation rates for each of the nail designs selected for evaluation is presented, in addition to specific outcome measures relevant to that nail design which was explored: peri-implant fracture-short versus long nails, and specific mechanism of failure-blade versus plate.

CONCLUSIONS

Decreased failure of fixation and reoperations rates were found for integrated dual lag screw fixation. Similar fixation failure and reoperation rates were found for the long versus short nails and for blade versus screw fixation.

LEVEL OF EVIDENCE

Diagnostic, Level IV.

Strategies for Pertrochanteric Fracture Reduction and Intramedullary Nail Placement: Technical Tips and Tricks

The incidence of pertrochanteric hip fractures continues to rise as the aging population expands. Despite advancements in techniques and implants, failure rates remain up to 16% in the literature. The recognition of challenging fracture patterns and the use of meticulous preoperative planning can help to avoid common pitfalls. Understanding fluoroscopic views for reduction assessment and implant placement is instrumental in preventing fixation failure. In addition, adjunctive techniques including the use of a bone hook, cerclage wire, and colinear clamps can facilitate reduction efforts. It is imperative for the surgeon to recognize common pitfalls and to consider a wide array of techniques to manage these challenging and common fractures.

[Subtrochanteric fractures]

Subtrochanteric fractures represent a distinct entity. They are different from proximal femoral fractures as well as femoral shaft fractures. Nowadays, these fractures are mainly found in the geriatric population. Fractures in younger patients are indicative of high-energy trauma. Comorbidities are important in the geriatric population whereas accompanying injuries are most important in younger patients. Early surgical stabilization of subtrochanteric fractures is the treatment of choice, which under certain circumstances should also be carried out within the framework of damage control orthopedics. Long cephalomedullary nails represent the standard procedure. In geriatric patients the primary aim is weight bearing stability. The risk of complications with subtrochanteric fractures in the literature is relatively high. Classical compression plates play a role in the management of complications.