Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy
J. G. G. Dobbe
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J. C. Vroemen
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S. D. Strackee
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G. J. Streekstra
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J. C. Vroemen S. D. Strackee Department of Plastic, Reconstructive and Hand Surgery, Academic Medical Center, University of Amsterdam
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Amsterdam, The Netherlands
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J. G. G. Dobbe (&) G. J. Streekstra Medical Imaging Section, Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam
, Room No. L0-113-3, Meibergdreef 9, 1105 AZ Amsterdam,
The Netherlands
Preoperative three-dimensional planning methods have been described extensively. However, transferring the virtual plan to the patient is often challenging. In this report, we describe the management of a severely malunited distal radius fracture using a patient-specific plate for accurate spatial positioning and fixation. Twenty months postoperatively the patient shows almost painless reconstruction and a nearly normal range of motion.
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Malunion following a distal radius fracture is a common
complication treated by osteotomy surgery. Accurate
reconstruction is important since a statistically significant
relationship has been found between malpositioning and
clinical outcome [1]. It has been shown that standard
anatomical plates may lead to considerable positioning
errors in individual patients [2]. Three-dimensional (3D)
techniques are increasingly valuable for preoperative
osteotomy planning [38]. However, implementing the
Fig. 1 Anteroposterior and lateral radiographs of the affected wrist
(top row) revealing a malunion of the radius and of the mirrored
healthy wrist (bottom row)
preoperative planning (Philips Brilliance 64 CT scanner,
Cleveland, OH; voxel size 0.45 9 0.45 9 0.45 mm,
120 kV, 150 mAs, pitch 0.6). The affected left and
mirrored healthy right radii were segmented and proximally
aligned to visualize the malunion (Fig. 2a). An anatomical
coordinate system (Fig. 2a) was defined to quantify the
deformity. The affected radius was shortened (9.9 mm). It
also showed dorsal and radial collapse (31.4 and 8.8 ), and
rotational deformation (3.7 ). These rotations revolve
around the three axes of the anatomical coordinate system
(x, y and z, respectively). Distal and proximal segments,
excluding the deformity, were subsequently aligned with
the mirrored image of the contralateral bone by registration
[9, 10], to find the right anatomical alignment. Next, the
position of the distal radius was corrected for bilateral
length differences, to restore a normal ulnar variance. This
quantification defined the complete relative position of the
distal and proximal segments (Fig. 3b). Correcting the
relative bone position required translations in the
radioulnar, dorsopalmar and proximodistal direction of 4.8, 12.5
and 9.9 mm, respectively. Dorsopalmar flexion, radioulnar
deviation and supinationpronation rotation required
angular corrections of 31.4 , 8.8 and 3.7 .
To be able to bring the distal radius segment to the
planned position, we first conducted a simulation using a
Fig. 2 a Mirrored healthy radius (white) proximally aligned with the
affected left radius. The affected radius is markedly shortened, shows
a rotation deformity, and shows radial and dorsal collapse. The
anatomical coordinate system is used to quantify the deformity.
b Planned position of the distal radius (green) based on the
contralateral side and corrected for bilateral length discrepancy
Fig. 3 Simulation of surgical treatment. a Affected bone with drilling
and cutting guide, b distal bone segment in planned position, showing
predrilled holes for screw fixation, c custom titanium plate with
porous defect-filling augment for realignment and fixation
patient-tailored plate [10], in combination with a porous
defect-filling augment to fill the osteotomy gap and to
provide additional mechanical support. To use the custom
plate, predrilling for screw fixation and cutting the bone at
the planned position is required. This is achieved using a
drilling and cutting guide (Fig. 3a), which is tightly fitted
to the patients own bone geometry. After application of
the drilling and cutting guide, the plate and augment can be
used to restore anatomical alignment of the distal and
Fig. 4 Surgical procedure showing, a fixation of the polyamide
drilling and cutting guide using K-wires, b result of predrilling and
partial cutting through guide slit. c Insertion of porous titanium mesh.
d Mesh mounted to custom plate, custom plate fixated to bone using
locking screws
proximal segments (Fig. 3c). Position planning was
performed using custom software [10].
To transfer the simulated virtual plan to the patient, a
polyamide drilling and cutting guide, and a titanium plate
and mesh (average porosity 70 %, average pore size
720 lm, thickness of solid struts *350 lm) were created
using additive manufacturing technologies. Guide and
implant design and production were outsourced (Mobelife
N.V., Leuven, Belgium).
After a volar approach of the distal radius, the polyamide
guide tightly fit the bon (...truncated)