Keywords radial deformity - radial fractures complications - x-ray tomography - three-dimensional
printing
Introduction
Distal radial fractures are very common, accounting for up to 75% of forearm fractures.[1 ] Their distribution is bimodal, affecting mostly young men subjected to high-energy
trauma, or patients > 65 years old, predominantly females, with bone fragility-osteopenia
who suffered low-energy trauma.[1 ]
[2 ] An epidemiological study carried out from 1999 to 2010 in Sweden, with a population
of 11.2 million inhabitants, revealed an incidence of 278 distal radial fractures
for every 100,000 people, with a gender ratio of three women per man.[2 ] Correspondingly, the city of São Paulo, Brazil, with a population of 12.2 million
inhabitants, would have > 41,000 fractures in the same period; considering that up
to 33% of these fractures evolve with vicious consolidation,[3 ]
[4 ] approximately 13,000 patients would be affected. These figures demonstrate the importance
of studies promoting the prevention and treatment of this clinical condition.
There is still no consensus on the best way to treat distal radial fractures[.3 ] Despite constant developments in surgical techniques and implants, complications
still occur; the most common include posttraumatic arthrosis, tendon rupture, median
nerve compression, and vicious consolidation.[3 ]
[4 ] Vicious consolidation can occur in up to 33% of cases,[4 ] mostly after nonsurgical treatment.
Vicious distal radial consolidation can lead to a range of functional and painful
limitations depending on the deformity type. Angular deformities result in an abnormal
compensatory movement in the midcarpal joint that causes wrist instability followed
by pain, limited movement, and degenerative arthrosis. Radial shortening deformities
can lead to ulnocarpal impingement and instability of the distal radioulnar joint.
Joint step deformities are highly probable of evolving with degenerative wrist changes.
Knirk et al.[5 ] assessed functional outcomes from distal radial treatment in young adults and found
out that joint congruence was a critical factor for success. Post-traumatic arthrosis
occurred in 11% of patients with no joint step deformities, compared to 91% subjects
with non-congruent joints.[5 ] These changes resulted in functional limitations that can lead to permanent work
disability.
Corrective osteotomies for vicious distal radial consolidation aim to recover the
normal bone anatomy for functional improvement and pain relief; in addition, these
procedures prevent the progression of degenerative changes at the wrist joint. Since
vicious consolidation presentations are widely variable, there are many corrective
osteotomy techniques, but the common point for their indication is the presence of
pain and functional limitation in patients with no advanced radiocarpal arthrosis.
Surgical correction has a significant clinical benefit.[6 ]
Clinical and radiological analysis are critical for the good outcome of deformity
correction. In addition to posteroanterior and true lateral radiographic views of
both the affected and contralateral wrist, the use of computed tomography (CT) is
essential to assess joint impairment and improve surgical planning, especially in
vicious consolidations with joint involvement.[7 ]
Recently, CT with three-dimensional (3D) reconstruction has been used for prototyping
in a 3D model using polylactic acid (PLA). It allows for a better understanding of
the deformity, and it has great value for surgical planning.[6 ]
[7 ] Careful planning prior to the surgical procedure, in a 3D model with the actual
dimensions from the patient, allows the surgeon to validate the type of implant to
be used and to predict procedural steps and strategies. This approach reduces surgical
time, improves implant selection and placement, and validates the exact location and
direction of the osteotomy required for deformity correction.[7 ]
[8 ] About 2 years ago, a prototyping laboratory with 3D printing resources was implemented
with the support from the São Paulo Research Foundation (Fundação de Amparo à Pesquisa do Estado de São Paulo [FAPESP, in the Portuguese acronym]), allowing us to start the development of studies
using the technique described below.
Indications and Contraindications
Indications and Contraindications
Preoperative planning using 3D printing in a prototyped model (PLA) of distal radial
vicious consolidation is recommended for all corrective surgeries due to the complex
anatomical distortion related to this clinical condition. This strategy allows for
a better 3D understanding and real correction in patients who present anatomical deformity
and significant functional limitation.
Corrective osteotomies for distal radial vicious consolidation are contraindicated
in patients with low demand for daily activities, mild anatomical deformity, little
functional restriction, long-standing injury, or radiocarpal degenerative osteoarthritis.
Thus, in deformities with sustained articular or extra-articular incongruence, we
recommend a more specific assessment of the degree of joint cartilage degeneration
using nuclear magnetic resonance or wrist arthroscopy; correction with osteotomy is
contraindicated if severe joint degeneration is present.
Preoperative Technique
Bilateral CT scans of the wrists must be performed in 1 mm-thickness sections. The
file is generated in Digital Imaging and Communications in Medicine (DICOM) format
and standardization and then imported into a 3D medical image processing and reconstruction
software (InVesalius version 3.1.1, Centro de Tecnologia da Informação Renato Archer,
Campinas, SP, Brazil). This 3D model of the distal radio is exported as a Standart
Tessellation Language/STereo-Lithography (STL) file and the Simplify3D software (Simplify3D:
Cincinnati, Ohio, USA) translates the information from the .stl file into instructions
for the 3D printer. The material for 3D printing is PLA.
The corrective osteotomy was planned after preparing prototypes from the deformed
distal radius and the normal contralateral bone. Plate positioning, screw length,
and osteotomy location must be evaluated using C-arm fluoroscopy for proper selection
of surgical materials.
Surgical programming with 3D reconstruction and PLA model prototyping allows the surgeon
to better understand the deformity, plan the exact osteotomy location under real perspective
and determine the best type of implants and their specifications. As such, it anticipates
and optimizes surgical stages, resulting in a safer, faster, more predictable deformity
correction. This research project was analyzed and approved by the ethics committee
under the number 9253251119.
Selected Cases
Case 1–Female patient, 46 years old, with sequelae from a left distal radial fracture.
This injury occurred 4 years ago, when it was treated with plastered immobilization.
She presents pain and limited flexion at the left wrist. Posteroanterior and true
lateral radiographies of the left wrist show vicious consolidation ([Figure 1 ]). Bilateral distal radius prototyping based on CT scans with 3D reconstruction improved
deformity understanding and surgical planning ([Figure 2 ]).
Fig. 1 Posteroanterior (A) and true lateral (B) radiographies of the left wrist showing
vicious consolidation with dorsal deviation, radial shortening, ulnar head deformity,
and adaptive carpal instability.
Fig. 2 Planning and surgery with prototyping in a PLA model: guidewires placement for osteotomy
in model (A, B) and fluoroscopic control of model osteotomy (C, D), prototyping after
corrective osteotomy and dorsal plate fixation (E, F). Postoperative follow-up radiographies
(G, H).
Case 2–Male patient, 47 years old. The subject presented a distal fracture at the
right radius 4 months ago, which was submitted to nonsurgical treatment. Wrist radiographs
show vicious consolidation with loss of volar inclination and widening of the joint
surface of the distal radius with radiocarpal joint step ([Figure 3 ]). As in the previous case, a PLA model from both distal radial bones of the patient
was printed and used to outline the osteotomy point and deformity correction. ([Figures 4 ] and [5 ]).
Fig. 3 Posteroanterior (A) and lateral (B) radiographies of the distal portion of the right
radius showing vicious consolidation with radiocarpal joint step and loss of normal
radial volar tilt.
Fig. 4 Dorsal view: planning of the corrective articular osteotomy of the distal portion
of the right radius in a printed model (A), and fluoroscopic image after locked dorsal
plate fixation at the distal radius (B). Lateral view: articular osteotomy of the
distal radius and locked dorsal plate fixation in a printed model (C), and fluoroscopic
image with corrected radiographic parameters (D).
Fig. 5 Posteroanterior (A) and lateral (B) radiographies 4 weeks after surgery. Joint step
reduction and enlargement of the radial articular surface as performed during the
preoperative planning in a PLA model.
Discussion
In the early 1980s, Charles Hull developed and conceptualized 3D printing, allowing
the creation of objects based on material deposition layer by layer. Since then, 3D
printing advanced and models present better resolution, faster production, and lower
cost; in addition, there is a greater variety of materials for printing.[7 ]
The use of 3D prototyping in orthopedic surgery allows for a better 3D understanding
of the fracture or its vicious consolidation. Visualization and manipulation of models,
which are true to the patient's anatomy, help surgical programming and intraoperative
decision making.
Final Considerations
In cases of vicious consolidation of the distal portion of the radius, printing a
model based on the 3D reconstruction of CT scans helps the surgeon to select proper
implants and determine the direction and location for corrective osteotomy. This preoperative
planning saves surgical time, resulting in a lower rate of complications and in a
more favorable functional outcome.
