Reconstruction interlocking nails for ipsilateral femoral neck and shaft fractures: biomechanical analysis of effect of supplementary cannulated screw on intracapsular femoral neck fracture

A biomechanical comparison of three fixation methods for unstable femoral neck fractures with medial calcar defect

BACKGROUND

Unstable femoral neck fractures with medial calcar defects are difficult to manage. The optimal fixation methods for these fractures have been a subject of ongoing debate among orthopedic surgeons. In this study, three different fixation techniques for vertical, medial defected femoral neck fractures were compared.

METHODS

In this study, a biomechanical analysis was conducted to compare three fixation methods: cannulated screws (Group 1), cannulated screws combined with a medial buttress plate (Group 2), and intramedullary nails (Group 3). Synthetic composite bone models representing vertical collum femoris fractures with medial calcar defects were used. Each group consisted of seven specimens, and, to maintain consistency, a single surgeon performed the surgical procedure. Biomechanical testing involved subjecting the specimens to axial loading until failure, and the load to failure, stiffness, and displacement values were recorded. Normality was tested using the Shapiro-Wilk test. One-way ANOVA and Tukey's HSD post hoc test were used for comparisons.

RESULTS

The difference in the load to failure values was statistically significant among the groups, with Group 2 exhibiting the highest load to failure value, followed by Group 3 and Group 1. Stiffness values were significantly higher in Group 2 than in the other groups. Displacement values were not significantly different between the groups. Fracture and displacement patterns at the point of failure varied across the groups.

CONCLUSION

The results of this study indicate that fixation with a medial buttress plate in combination with cannulated screws provides additional biomechanical stability for vertical femoral neck fractures with medial calcar defects. Intramedullary nail fixation also demonstrated durable stability in these fractures. These findings can be used to better understand current management strategies for these challenging fractures to promote the identification of better evidence-based recommendations.

"Reverse miss-a-nail technique" of reconstruction nailing for successful fixation of the ipsilateral femoral neck and shaft fracture

INTRODUCTION

Although reconstruction nails have an advantage of single-construct fixation in ipsilateral femoral neck and shaft fractures, they have not been used widely due to the technical challenges associated with their placement. Reduction is particularly demanding in patients with displaced neck fractures after nailing of the shaft fracture, and can be resulted in nonunion, malunion, and osteonecrosis. We report a new technique of reconstruction nailing after the provisional reduction and fixation of a neck fracture to achieve successful healing of this injury.

MATERIALS AND METHODS

Osteosynthesis using a reconstruction nail was performed in ten consecutive patients with displaced femoral neck and shaft fracture. After closed reduction of the displaced neck fracture, the femoral neck was provisionally fixed with pins in an anterolateral-to-medial direction. While maintaining reduction of the neck fracture, a nail was inserted and passed into the medullary canal posterior to the provisionally fixed pins with indirect reduction of the shaft fracture. After two reconstruction locking screws were fixed for proximal interlocking, the provisional pins were removed once distal interlocking was achieved. The radiologic outcomes included quality of reduction, healing rate, and time to the union were appraised, and the functional outcomes were assessed with Friedman and Wyman's criteria.

RESULTS

This novel technique provided satisfactory reduction of both the femoral neck and shaft fractures with no malunion. All fractures achieved primary union, except for one case of nonunion of femoral shaft. Eight of ten patients experienced good results in functional outcome, whereas the remaining two patients reported moderate limitations in activities of daily living. At the latest follow-up, all patients had excellent range of motion in hip and knee joints.

CONCLUSIONS

Provisional fixation after reduction of a femoral neck fracture may facilitate successful reconstruction nailing in the ipsilateral fractures of the femoral neck and shaft. This "Reverse Miss-a-Nail Technique" may minimize complications and maximize the radiologic and functional outcomes of patients who experience this injury.

Ipsilateral femoral neck and shaft fractures fixation with proximal femoral nail antirotation II (PFNA II): technical note and cases series

Background

Combined ipsilateral femoral neck and shaft fractures are an uncommon type of fractures. A number of different implant options are available for the management of this injury. Two-device procedures were suggested because of the higher rate of malunion by single-device treatment. However, surgical treatment using a cephalomedullary nail is still an alternative option that provides better mechanical advantage and minimal invasion. This study details the technique of treating these pattern fractures with proximal femoral nail anti-rotation II (PFNA-II) to achieve an acceptable reduction in both fracture sites.

Methods

Ten cases of ipsilateral femoral neck and shaft fractures under reduction by PFNA II were included and reviewed. A saw-bone model was also utilized to perform the detailed technique of reduction and fixation of PFNA II.

Results

Under the special technique by using the PFNA II, all ten cases achieved optimal reduction and alignment of both fracture sites in intra-operative fluoroscopy. There was no intra-operative complication noted. After 6 months of follow-up, radiography revealed proper alignment and well union of the fractures.

Conclusions

Fixation of ipsilateral femoral neck and shaft fractures with a single construct provides advantages of good biomechanical function, minimal invasion, reduced blood loss, and less operation time when comparing to two-device fixation. Thus, if acceptable reduction could be achieved, fixation by one PFNA II was a good alternative choice for this injury pattern.

Biomechanics of Femoral Neck Fractures and Implications for Fixation

Fractures of the femoral neck can occur in young healthy individuals due to high loads occurring during motor vehicle accidents, impacts, or falls. Failure forces are lower if impacts occur sideways onto the greater trochanter as compared with vertical loading of the hip. Bone density, bone geometry, and thickness of cortical bone at the femoral neck contribute to its mechanical strength. Femoral neck fractures in young adults require accurate reduction and stable internal fixation. The available techniques for fracture fixation at the femoral neck (cannulated screws, hip screw systems, proximal femur plates, and cephallomedullary nails) are reviewed with respect to their competence to provide biomechanical stability. Mechanically unstable fractures require a load-bearing implant, such as hip screws, with antirotational screws or intramedullary nails. Subcapital or transcervical fracture patterns and noncomminuted fractures enable load sharing and can be securely fixed with cannulated screws or solitary hip screw systems without compromising fixation stability.

Delayed recognition of an ipsilateral femoral neck and shaft fracture leading to preventable subsequent complications: a case report

BACKGROUND

Ipsilateral femoral shaft and neck fractures are rare injuries, affecting mostly young patients who sustained high-energy traumas. In 19-50% of cases, the femoral fracture is misdiagnosed or overlooked at the initial presentation, with reportedly increased risk of complications such as non-union and avascular necrosis. We present a case of an ipsilateral femoral neck and shaft fracture, which was missed at initial presentation despite radiographic and computed tomography (CT) scan evaluation.

CASE PRESENTATION

A 56-year old female was admitted to our institution following a high-energy trauma (fall from 6 m). Initial radiographic and CT scan evaluation revealed a displaced femoral shaft fracture but no other femoral fractures were detected. Closed reduction and external fixation of the femoral shaft fracture was performed in the emergency setting. Follow-up radiologic evaluations revealed an ipsilateral laterally displaced femoral neck fracture. Despite cephalomedullary nail fixation of both fractures performed on the third day from the initial injury, the patient developed a non-union of the femoral neck fracture, which led to cut-out of the lag screw with associated varus failure of the femoral neck fracture requiring surgical revision and implant of a bipolar hemiarthroplasty at one year follow up. The postoperative course was uneventful and the patient had a full long-term recovery.

CONCLUSION

This case report exemplifies the need to maintain the highest level of suspiciousness for the concomitant presence of an ipsilateral femoral neck fracture when treating polytraumatized patients who sustained a femoral shaft fracture as a consequence of a high-energy trauma. Furthermore, the pre-operative standardized radiological evaluation (plain x-ray and CT scan) might not always help in ruling out these fractures. It is therefore necessary to adopt additional standardized radiographic protocols not only in the pre-operative but also in the intra-operative and immediate post-operative settings.

Biomechanical rationale for implant choices in femoral neck fracture fixation in the non-elderly

Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. The cornerstone of their management is anatomic reduction and stable internal fixation of the femoral neck in an attempt to salvage the femoral head. Complications including avascular necrosis of the femoral head, non-union and post-traumatic osteoarthritis are not uncommon. The clinical outcomes of these patients can be improved with good pre-operative planning, optimization of surgical procedures and introduction of new improved implants and techniques. In the herein study, we attempt to describe the biomechanical properties of the hip and compare the performance of the most commonly used devices. Experimental evidence suggests that in Pauwels type III fracture patterns a cephalomedullary nail was significantly stronger in axial loading. Moreover, in unstable basicervical patterns cannulated screws (triangular configuration) demonstrated a lower ultimate load to failure, whereas in subcapital or transervical patterns both the cannulated screws (triangular configuration) and the sliding hip screw demonstrated no compromise in fixation strength. The fracture pattern appears to be the major determinant of the ideal type of implant to be selected. For a successful outcome each patient needs to be considered on an individual basis taking into account all patient and implant related factors.

Reconstruction nailing for ipsilateral femoral neck and shaft fractures

The surgical management of ipsilateral fractures of the femoral neck and shaft presents a difficult and challenging problem for the orthopaedic surgeon. The purpose of the present study was to report the mid-term results and complications in a series of patients who sustained ipsilateral femoral neck and shaft fractures and treated in our trauma department with a single reconstruction nail for both fractures. Eleven patients were included in the study with an average age of 46.4 years. The mean follow-up was 47 months (range, 15-75 months). There were no cases of a missed diagnosis at initial presentation. The mean time to union was 4.5 months for the neck fracture and 8.2 months for the shaft. There were no cases of avascular necrosis of the femoral head or non-union of the neck fracture. The mean Harris Hip Score was (85 ± 4.3). Complications included two cases of shaft fracture non-union and one case of peroneal nerve palsy. Heterotopic ossification at the tip of the greater trochanter was evident in two cases without causing any functional deficit. The current study suggests that reconstruction nailing produces satisfactory clinical and functional results in the mid-term. The complications involved only the femoral shaft fracture and were successfully treated with a single operative procedure.