Malunion of distal radius fractures is a frequently seen complication, occurring in approximately 5% of distal radius fractures . Up to 83% of malunited distal radius fractures are symptomatic, causing pain, weakness or functional impairment of the joint [1,2,3]. These symptomatic malunited distal radius fractures often require surgical correction to restore the anatomy of the wrist and improve functional outcome.
The indication for surgical correction is predominantly based on the degree of functional impairment and correctable radiographic findings that potentially cause the patients’ complaints [3, 4]. The functional impact of the deformity is patient-specific, depending on the age, dominance of the affected arm and activity level of the patient [3, 5].
Acceptable limits of radiographic deformation have been established for the distal radius (Table 1) [3, 6, 7]. Within these limits, symptoms of distal radius malunions are expected to be minimal . Nonetheless, acceptable values vary between individuals. Often the unaffected contralateral forearm of the patient is used as a reference to evaluate patient-specific degrees of malformation [9,10,11].
Several studies have shown that accurate anatomic reconstruction of the malunited radius can improve functional outcome in patients with a symptomatic malunion [11,12,13]. A corrective osteotomy is the treatment of choice to restore the anatomic configuration and optimize functional outcome [5, 10, 11, 14].
In order to optimize accuracy of the planned corrective osteotomy, extensive preoperative planning is indispensable. Radiographic evaluation of the affected limb aids in obtaining details of the deformity and determining the osteotomy plane, the fixation method, and in some cases the shaping of a bone graft [8, 15, 16].
Traditionally, preoperative planning is based on 2 orthogonal radiographs depicting lateral and posteroanterior views of the radius [11, 17, 18]. With this method, however, complex deformations are often not addressed [18,19,20]. Especially, rotational deformities are difficult to assess on plain radiographs [8, 15, 18]. Computer-assisted techniques with three-dimensional (3-D) images and models address 3-D deformity and may further optimize functional and radiographic results of corrective osteotomies [21,22,23,24].
3D-planned corrective osteotomies usually involve three steps [19, 25]. Firstly, data are collected by obtaining a CAT scan of the malunited and contralateral healthy forearm. Secondly, virtual models are created of both radii. By superimposing the malunited radius on a mirrored version of the healthy contralateral side, the location and degree of deformity is determined. Subsequently, a virtual cutting plane is set within the region of the malunion, which divides the bone in a proximal and distal part. The distal and proximal part of the malunited radius can be rotated and translated to match with the contralateral radius . With the third and last step, the preoperative plan is translated to the patient during actual surgery [21, 22].
Transferal of the planned osteotomy to the patient’s bone is a delicate task for which multiple solutions have been suggested. In its simplest form, virtual or physical 3D models aid the surgeon in understanding and visualizing the planned osteotomy plane . Additionally, there is the possibility to guide the reposition with optical tracking devices [19, 28]. Another option is the use of synthetic templates that can be placed in the osteotomy gap, thereby restoring the original position of the distal radius [23, 29]. Ultimately, 3D-planning techniques provide the possibility to create patient-specific surgical cutting guides and fixation plates [21, 22, 26, 27, 30,31,32,33,34]. Templates are made to match the patients’ anatomy and include drilling guides and one or more osteotomy slits. Successively, the corrected position can be secured with the use of preoperatively defined, patient-specific plates.
Advances in computer technology and 3D printing facilities have made these techniques more accessible in daily clinical practice . Therefore, the aim of this study was to assess the results of corrective osteotomies of a malunited distal radius with the use of 3D planning techniques by systematically evaluating the available literature.