Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy

Strategies in Trauma and Limb Reconstruction, Nov 2014

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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Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy

J. G. G. Dobbe 0 1 J. C. Vroemen 0 1 S. D. Strackee 0 1 G. J. Streekstra 0 1 0 J. C. Vroemen S. D. Strackee Department of Plastic, Reconstructive and Hand Surgery, Academic Medical Center, University of Amsterdam , Amsterdam, The Netherlands 1 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. - 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)


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J. G. G. Dobbe, J. C. Vroemen, S. D. Strackee, G. J. Streekstra. Patient-specific distal radius locking plate for fixation and accurate 3D positioning in corrective osteotomy, Strategies in Trauma and Limb Reconstruction, 2014, pp. 179-183, Volume 9, Issue 3, DOI: 10.1007/s11751-014-0203-1