Three-Dimensional Planning and Surgical Guidance of Malunion Correction

Key Points

Malunion is the most common complication following a distal radius fracture.
Restoration of anatomy is a key factor in obtaining good functional outcome, but this can be technically challenging.
Next to radiographs and CT-scans, three-dimensional (3D) visualization and printed bone models can further improve understanding of the malunion pattern.
The use of three-dimensional (3D) computer planning and the production of patient-specific instruments allow accurate and reproducible correction, especially in complex malunion patterns.
The additional cost is one of the major disadvantages of the 3D technique.
Further clinical investigations are necessary to better define the added value, the indications, and cost-effectiveness of 3D technology in the treatment of malunions.

Panel 1: Case Scenario

A 48-year old woman sustained a severely displaced intra- and extra-articular fracture of the left distal radius. She was initially treated at another facility with closed reduction, additional external fixation, and K-wires.

She presented 8 months later, with an intra- and extra-articular malunion, causing persistent wrist pain (VAS 8/10) and severe functional impairment (Quick-DASH 62).

Physical examination revealed residual pain at the radiocarpal and distal radioulnar joint, restricted wrist movement, and decreased grip strength. The Modified Mayo Wrist score was poor (MMWS 10).

Can 3D technology provide a more accurate reduction and better outcome of her complex distal radius malunion ( Fig. 1 )?

Fig. 1, Lateral and postero-anterior radiographs of the wrist showing a combined intra- and extra-articular malunion of the distal radius.

Importance of the Problem

Malunion of the distal radius is a common complication, with a reported incidence of up to 23% of nonsurgically treated distal radius fractures. It often causes persistent wrist pain and functional impairment. Additionally, secondary carpal malalignment and intraarticular deformities can lead to early degenerative changes.

When surgical treatment is deemed necessary, a corrective osteotomy is the procedure of choice, and clinical studies have shown a significant correlation between the precise reconstruction of normal anatomy and the clinical outcome.

Planning and performing a corrective osteotomy can be a technically challenging procedure. Conventional two-dimensional radiographs are limited in the visualization of complex intraarticular or rotational deformities of the malunited wrist. And studies have shown that even following careful planning, restoration of bony alignment was only obtained in 40% of patients. A complication rate of up to 42% has been reported following corrective osteotomy, with tendon injuries and delayed or nonunion being the most commonly reported problems.

Three-dimensional technology might address some of these problems, and improve outcome following corrective surgery ( Box 1 ).

Box 1

The 3 Steps of 3D Technology.

Step 1 DICOM (Digital Imaging and Communications in Medicine) data are collected through computed tomography (CT) scans of the malunited and the contralateral forearm. This can be done simultaneously with the patient in the prone position, shoulders in full extension and both arms overhead, to decrease radiation exposure. To allow precise 3D reconstruction of bony anatomy, a specific scanning protocol needs to be followed with scanning parameters set at a tube current of 10–30 mA and voltage of 90–120 kV, a slice thickness of < 0.625 mm and a field of view of 200 mm × 200 mm or smaller.
Step 2 Virtual 3D models (STL files) are created, using dedicated medical image processing software. Precise assessment of the deformity in all planes is now possible and corrective surgery can be planned in detail, based on the healthy contralateral side.
Step 3 3D technology will allow this virtual plan to be translated to the operation room, and multiple methods have been developed to do this: virtual and three-dimensional printed bone models, optical tracking devices, synthetic or bony prefabricated wedges that fit into the osteotomy gap, and the use of patient-specific surgical cutting and drilling guides. The last one appears to be the most promising technique. The drilling and cutting guides are designed based on the surgical plan, and 3D printed in medical-grade material that can be sterilized.

Main Question

What is the added value of three-dimensional (3D) planning and surgical guidance compared to more conventional techniques in the correction of distal radius malunions?

Current Opinion

Most surgeons are confident that preoperative planning with two-dimensional (2D) imaging for corrective osteotomy of distal radius malunions leads to acceptable results and complication rates in the majority of cases. They argue that 3D technology complicates the procedure without proven added value or cost effectiveness.

Finding the Evidence

Cochrane library: Distal radius malunion
Pubmed (Medline): ((Colles’ fracture* [tiab] OR distal radius fracture* [tiab]) AND (Three-dimensional [tiab] OR 3D [tiab] OR 3-D [tiab] OR computer assisted [tiab] OR computer simulated [tiab] OR computer aided [tiab] OR virtual planning) AND (Malunited fracture* [tiab] OR malunion [tiab] OR osteotomy [tiab] OR corrective osteotomy [tiab]))
Randomized controlled trials (RCTs), systematic reviews, case series, and case reports published between January 1, 2000, and January 20, 2020 were considered
Review of references of eligible studies
Articles that were not in English, French, German or Dutch were excluded

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