Key Points
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CT scan can allow for improved identification of intraarticular fracture fragments in distal radius fractures.
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Use of CT scan for preoperative planning can allow for improved guidance of fracture fragment fixation intraoperatively.
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Utilization of CT in association with 3D printing can allow for improvement in the surgical treatment of distal radius malunions.
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Currently available 3D CT reconstruction technology has significant limitations as it is only a 2D projection of the 3D data set. True 3D modeling allows for virtual preoperative planning and can provide invaluable information to the surgeon.
Conflict of Interest
Associate Professor Sandow has been involved in the development of interactive 3D imaging ( www.truelifeanatomy.com.au and www.rubamas.com ) and has a potential conflict of interest in the subject of the paper.
A 48 year-old, right-handed female visited the emergency department with a right wrist deformity after a fall on the outstretched hand. Radiographs shows an intraarticular distal radius fracture with 25 degrees of dorsal angulation and dorsal metaphyseal as well as intraarticular comminution ( Fig. 1 A–C ). What is the most effective approach to preoperative planning for this fracture?
Importance of the Problem
Distal radius fractures are a common injury, and diagnosis of fracture patterns and stability are critical factors in the management of these fractures. Identification of fracture patterns in intraarticular fractures can affect the determination of optimal fixation technique. Preoperative computed tomography (CT) can aid in the identification of intraarticular fracture patterns and guide treatment. CT can also be a beneficial adjunct in the treatment of distal radius malunion correction, especially when combined with 3D modalities.
Confusion over the functionality of the various forms of 3D imaging has created challenges in expanding the use of such technology, with cost, time, and access convenience being potential issues. Sandow has detailed some of the technical aspects of both volume rendering (which is the predominant 3D modality in medical CT) and surface rendering (which is the predominant 3D modality use outside of the field of medicine).
3D printing technology is an advanced preoperative planning tool that can be utilized to decrease operative time, blood loss, and fluoroscopy use ( Fig. 2 ). However, improved surgeon access to computer based digital 3D simulation may improve the contribution and utility of such advanced imaging techniques to improve preoperative planning, implant selection, and optimal technique in malunion correction.
Main Question
What is the utility of advanced imaging techniques in the diagnosis, preoperative planning, and treatment of distal radius fractures?
Current Opinion
Displaced intraarticular distal radius fractures are often treated surgically. Current opinion is variable with regard to preoperative imaging and the utility of advanced imaging (CT scan, 3D reconstruction, etc.) in surgical decision making.
Finding the Evidence
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Cochrane search: Distal Radius Fracture CT Scan; Distal Radius Fracture MRI; Distal Radius Fracture 3D CT Scan.
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Pubmed (Medline): (“distal radius fracture”) AND (“CT Scan” OR “MRI” OR “3D”).
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Articles not in English were excluded from review.
Quality of the Evidence
| Levels of Evidence—Sackett | ||
|---|---|---|
| Level | Description | Included Studies |
| 1 | Randomized controlled Trial | 1 |
| 2B | Cohort study or randomized controlled trial with methodological limitations | 1 |
| 3B | Case-controlled study | 21 |
| 4 | Case series | 27 |
| 5 | Expert opinion | 5 |
Findings
One level-1 and one level-2 studies were identified and met inclusion criteria for review, the first describing the utilization of a 3D printed wrist model based on CT images for preoperative planning in distal radius malunion correction, and the second with the finding that traction radiographs are a suitable alternative to CT in determining a treatment strategy in acute distal radius fractures. Buijze et al. identified a potential for improved accuracy and consistency of malunion correction with computer assisted surgical planning and patient-specific osteotomy guides.
Twenty level-3 studies and 25 level-4 studies met inclusion criteria, covering a range of topics related to the identification and treatment of both acute distal radius fractures, as well as malunion correction.
Eight level-3 studies including 429 distal radius fractures and 13 level 4 studies including 516 fractures, describe the advantage of CT in the diagnosis and treatment of acute distal radius fractures when compared to plain radiographs alone. Each of these studies describe the benefit of preoperative CT in patients with a distal radius fracture, allowing for improved identification of intraarticular fracture propagation into both the radiocarpal and distal radioulnar joint. Multiple studies identify the addition of CT as clearly superior to radiographs alone in the identification of intraarticular fracture propagation, especially into the sigmoid notch. Intraoperative CT has been reported useful in the identification of intraarticular screw penetration as well as articular step-offs. CT also has utility in preoperative planning of distal radius malunion correction. Identified limitations of the utilization of CT in the assessment of distal radius fractures include cost and limited valuable information beyond the identification of intraarticular fracture fragments.
Four level-3 studies and four level 4 studies describe the utility of advanced imaging in the diagnosis of concurrent injuries with distal radius fractures. Freedman et al. identified a 45% occurrence of TFCC pathology with an acute distal radius fracture, identified on MRI of 60 patients with an acute distal radius fracture, with higher prevalence in Frykman VI and VII fractures compared to other grade injuries. Von Schnieder-Egestorf et al. reviewed 603 distal radius fracture CT scans, and identified injury to the extensor tendon sheath in 71% of patients with an acute distal radius fracture, most commonly of the second or third extensor compartment. This was identified as fat-fluid levels or fatty effusions with the extensor compartments as seen on CT. In a review of 313 distal radius fracture CT scans, retrospectively, Heo et al. identified a 20.9% incidence of associated carpal fracture not identified on plain radiographs, thus identifying an additional benefit of CT scan in the assessment of complex distal radius fractures. Further reports suggest MRI allows for assessment of the TFCC and scapholunate complex, and can assist in the diagnosis of subtle concurrent osseous lesions, but does not improve functional outcome and appears to be of limited utility.
Seven studies (four level 3, four level 4 ), including 295 wrists, report the utility of 3D printing technology in the surgical treatment of distal radius fractures. 3D digital planning or 3D printing allows for advanced preoperative planning including implant selection and screw lengths. 3D printing technology in preoperative planning reduces intraoperative fluoroscopy, blood loss, and operative time but did not lead to an improvement in final wrist function compared to fractures that did not undergo 3D fracture printing for surgical planning. At present, a distal radius fracture model takes approximately 4 hours to print and has a cost of $10. Furthermore, 3D printed models were used in the preoperative planning of distal radius malunion correction in 24 patients and intraoperatively in 20 patients.
Six additional level-3 studies were identified which did not match any of the above subcategorizations. There are conflicting reports on the utility of arthroscopy in the treatment of distal radius fractures. Christiaens et al. found arthroscopy as a useful adjunct in improving intraarticular distal radius fracture reduction, but did not identify a benefit of arthroscopy in extraarticular distal radius fracture treatment. Saab et al. identified no functional benefit to intraarticular reduction with the addition of arthroscopy in the surgical treatment of a distal radius fracture. Sivrikaya et al. describes the use of ultrasonography in the emergency department as a diagnostic tool, with 100% specificity in identifying a distal radius fracture in a cohort of 93 patients. On CT imaging after distal radius fractures, Kim et al. did not find a correlation between DRUJ alignment on CT and DRUJ stability on physical exam. Other identified studies include the utility of MRI in improving the measurement of distal radius fracture displacement on lateral radiographs and the observation that the rate of CT utilization in the assessment and treatment of distal radius fractures did not increase over a 5-year period.
Furthermore, eight additional studies were identified with level-4 evidence outside of the above topics. Chatzikonstaninou et al. and Arealia et al. were unable to identify an improvement in the reproducibility of fracture classification by the addition of a CT scan to radiographs. In 46 patients after a distal radius fracture, Van Leerdam et al. found CT unreliable in diagnosing DRUJ instability. Murase et al. found 3D virtual simulation beneficial in the preoperative planning of growth arrest correction after a distal radius fracture. In a case series of three distal radius fractures, Atesok et al. found intraoperative CT adds 7.5 min to case length but did not identify the need for any reduction or screw revision. Das Graças Nascimento et al. found that CT did not influence the treatment proposed by experienced hand surgeons but was beneficial for less experienced surgeons in fracture pattern determination. Wijffels et al. noted fair interobserver reliability in identifying a coronal fracture line in the lunate facet with both radiographs and 2-dimensional CT.
Five level-5 studies were identified and included for completeness of Ref. .
Recommendation
In patients with an intraarticular displaced distal radius fracture, evidence suggests:
Conclusion
The use of advanced imaging, including CT scan, 3D modeling, and MRI in the treatment of distal radius fractures is of variable utility based on the current available literature. CT scan allows for improved identification of intraarticular fracture fragments, as well as DRUJ incongruity, but does not appear to improve surgical outcomes. Advanced imaging does increase the identification of concomitant injuries in distal radius fractures, but the utility of MRI in the assessment of distal radius fractures is limited. Access to a computer-based interactive 3D imaging environment may avoid some of the difficulties experience with 3D printing but is not currently routinely available. Such surgeon access may be the next expansion in advance imaging that will facilitate the assessment, therapeutic planning, and management of distal radial fractures.
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