Fracture of Distal Femur Clinical Trial
Official title:
MotionLoc Study: Healing of Distal Femur Fractures Stabilized With a Flexible Plating Construct Using MotionLoc Screws
The objective of this study is to document callus formation and healing of fractures stabilized with locking plates utilizing modern MotionLoc screws that provide controlled axial micro-motion to actively promote fracture healing.
Rigid locked plating constructs can suppress fracture healing, particularly at the near
cortex adjacent to the plate where interfragmentary motion is minimal. Dynamic fixation with
Far Cortical Locking (FCL) screws reduces construct stiffness and induces axial
interfragmentary motion to stimulate symmetric callus formation and healing. Two versions of
FCL screws are commercially available, but the clinical durability of this novel concept has
not been documented to date. This prospective observational study documented our early
clinical experience with MotionLoc® FCL screws for stabilization of distal femur fractures
to assess their durability and potential complications.
Thirty-two consecutive patients with 33 distal femur fractures (AO/OTA types 33-A and 33-C)
were prospectively enrolled at three trauma centers. Fractures were stabilized by plate
osteosynthesis with MotionLoc® FCL screws without supplemental bone graft or bone
morphogenic proteins. Thirty patients with 31 fractures were available for follow-up until
union or revision. Follow-up visits at 6, 12, and 24 weeks comprised functional and
radiographic assessment of implant fixation and fracture healing, including computed
tomography scans at week 12. The primary endpoint was fracture healing in absence of
complications and revision.
There was no incidence of implant breakage or diaphyseal fixation failure. Thirty of 31
fractures healed within 15.6 ± 6.2 weeks, as evident by bridging callus and pain-free load
bearing. There were two revisions, one at 5 days post surgery to correct a mal-rotation, and
one at 6 months post surgery to revise a non-union. Periosteal callus distribution at week 6
was symmetrical, with similar amounts of callus at the medial cortex (35%) anterior cortex
(30%) and posterior cortex (35%). In 23 fractures (74%), callus formation extended to the
lateral cortex under the plate.
Absence of hardware and fixation failure suggests that dynamic plating of distal femur
fractures with FCL screws provides safe and effective fixation. Moreover, the amount and
symmetric distribution of periosteal callus suggests that dynamic fixation with FCL screws
may promote increased fracture healing over standard locked plating. However, this
hypothesis on the stimulatory effect of dynamic fixation on fracture healing requires
investigation in a future randomized control trial.
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Observational Model: Cohort, Time Perspective: Prospective