[Correction of Intraarticular Malunion of the Distal Radius Based on a Computer-Assisted Virtual Planning]

Computer-assisted 3D-virtual planning of extraarticular corrective procedures at the distal radius and transfer of the virtually planned procedure to the radius in vivo has been recently described. In contrast to this analogue studies on intraarticular corrective procedures are still lacking. With regard to the difficulties of the technique and the potential risks a similar technique would be valuable, that overcomes the problems of the limited access and the difficulties of reposition and fixation. This study presents a technique for intraarticular corrective procedures at the distal radius based on computer assisted 3D- virtual planning and custom made patient specific instruments.

Between 2013 and 2016, 6 patients (1 female and 5 male) underwent intraarticular corrective osteotomy of the distal radius. The average age was 48 (38-60) years, the interval between injury and correction 10 (4-13) months. All patients had been previously operated externally. The computer-assisted planning was performed in cooperation with an external industrial partner ((Materialise NV, 15 Technologielaan, 3001 Leuven, Belgium). Therefore CT-scans of both wrists and forearms were performed at our institution following a special protocol from which both distal radii were virtually reconstructed. The mirror-image of the 3-D-model of the uninjured radius was superposed over the 3-D-image of the malunited radius so that the malunion was exactly visualized. The correction as well as the desired position of the implants was planned step by step via an online-conference. The stabilisation of the fragments was simulated by introducing plates and screws into the 3-D-images. Based on this plan for every step of the procedure patient-specific drilling and sawing guides were produced (Fa. Materialise) and supplied to our institution. The operative strategy and technique is demonstrated by a typical example and will vary with the individual situation of the patient.

No complications occurred. All patients gained bony union. No additional procedures were required. Postoperative CT-scans confirmed that step offs were regularly well corrected but gaps often persisted.