The treatment of a large segmental defect of over 6 cm in a long bone is a challenging procedure. Treatment options include cancellous bone graft (e.g., the Masquelet technique), vascularized fibular graft (VFG), and internal bone transport (IBT) with an external fixator. These methods may be performed with intramedullary (IM) nailing or plate fixation to enhance stability or to lessen the time of external fixation. Each method has its own advantages and limitations. This study aimed to describe the advantages of additional plate augmentation and autologous bone grafting after IM nail implantation. Three patients with large segmental femoral bone defects were treated with IM nail implantation; then, one- or two-stage autologous iliac bone grafting with additional plate augmentation was performed. All patients achieved bony union without metal failure. We describe a technique involving additional plate augmentation and autologous iliac bone grafting for treating large femoral defects after restoring the length of the femur using an IM nail implantation and an external fixator.
To prevent excessive sliding and subsequent fixation failures in unstable intertrochanteric fractures with posteromedial comminution, extramedullary reduction through overlapping of the anteromedial cortices of both proximal and distal fragments as a buttress has been introduced. The purpose of this study was to compare the biomechanical properties between two reduction methodsintramedullary reduction and extramedullary reduction-in treating unstable intertrochanteric fractures with posteromedial comminution (AO/OTA classification 31-A2.2). Materials and Methods: Eight pairs of frozen human cadaveric femora were used. The femora of each pair were randomly assigned to one of two groups: the intramedullary reduction group or the extramedullary reduction group. A single axial load-destruction test was conducted after cephalomedullary nailing. Axial stiffness, maximum load to failure, and energy absorbed to failure were compared between the two groups. Moreover, the pattern of mechanical failure was identified. Results: The mean axial stiffness in the extramedullary reduction group was 27.3% higher than that in the intramedullary reduction group (422.7 N/mm vs. 332.0 N/mm, p=0.017). Additionally, compared with the intramedullary reduction group, the mean maximum load to failure and mean energy absorbed to failure in the extramedullary group were 44.9% and 89.6% higher, respectively (2,848.7 N vs. 1,966.5 N, p=0.012 and 27,969.9 N•mm vs. 14,751.0 N•mm, p=0.012, respectively). In the intramedullary reduction group, the mechanical failure patterns were all sliding and varus deformities. In the extramedullary reduction group, sliding and varus deformities after external rotation were noted in 3 specimens, sliding and varus deformities after internal rotation were noted in 3 specimens, and medial slippage was noted in 2 specimens. Conclusion: In unstable intertrochanteric fractures with posteromedial comminution, the biomechanical properties of extramedullary reduction are superior to those of intramedullary reduction. Anteromedial cortex could be the proper buttress, despite a comminuted posteromedial cortex. It could help enhance the stability of the bone-nail construct.
Rationale:
Autosomal dominant type II (AD II) osteopetrosis is a rare inheritable metabolic bone disease characterized by hard but brittle bone and a narrow medullary canal. Intramedullary nailing (IMN) is a difficult but attractive option for the treatment of subtrochanteric fractures in patients with AD II osteopetrosis.
Patient concerns and diagnosis:
Two patients with AD II osteopetrosis sustained subtrochanteric fractures after a fall.
Interventions:
IMN was performed through the sequential use of instruments such as a 4.9-mm drill bit, small reamer, and larger reamer for over-reaming.
Outcomes:
In the first case, IMN left some gap at the fracture site. Dynamization was performed to treat the delayed union at 6 months postoperatively. The fracture healed at 10 months after the dynamization. In the second case, IMN was successful without a gap, and the fracture healed at 8 months.
Lessons:
Although IMN is difficult to perform owing to partial obliteration of the medullary canal in AD II osteopetrosis, it can be performed with sequential widening of the medullary canal using various instruments. In addition, the fracture gap should not be left uncorrected during IMN to attain fracture union.
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