Objectives:
To determine the effect of linking the intramedullary nail and the laterally applied locking plate bone to treat comminuted distal femur fractures and allow for immediate weight bearing..
Methods:
comminuted extra-articular distal femur fractures were created in 16 synthetic osteoporotic femurs and split into two groups: linked vs. unlinked. In the linked construct, in addition to standard plate bone fixation and proximal locking of the nail, two non-threaded locking bolts (prototypes) were placed through both the plate and the nail. In the unlinked construct, the same number of screws affixed the plate to the bone, but were directed around the nail and separate distal interlocking screws were placed for nail fixation. Each specimen underwent sequential axial and torsional loading and axial and torsional stiffness were calculated and compared.
Results:
On average, the unlinked constructs demonstrated a greater axial stiffness at all levels of axial loading and linked constructs demonstrated greater average rotational stiffness. However, there were no statistically significant differences (p > 0.189) between the linked and unlinked groups at any axial or torsional load.
Conclusion:
In distal femur fractures with metaphyseal comminution, there were no significant differences in axial or torsional stiffness when linking the plate to the nail. Linking the construct appears to provide no significant mechanical advantage compared to the unlinked environment, but may be a useful strategy to reduce nail “traffic” in the distal segment with no significant disadvantage.
