Comparison of three dimensional and radiographic measurements in the analysis of distal radius malunion

A comparison of 3-D CT and 2-D plain radiograph measurements of the wrist in extra-articular malunited fractures of the distal radius

Two-dimensional (2-D) plain radiographs may be insufficient for the evaluation of distal radial malunion, as it is a three-dimensional (3-D) deformity. This study introduced a 3-D measuring method that outputs radial inclination, ulnar variance, palmar tilt and axial rotation. To this end, a standardized and clearly defined coordinate system was constructed that allowed 3-D measurements closely resembling the conventional 2-D method in 35 patients. Mean differences between 3-D and 2-D measurements in affected wrists were 1.8° for radial inclination, 0.8 mm for ulnar variance and 3.7° for palmar tilt. In addition, inter- and intra-observer reproducibility of all 3-D and 2-D measurements were good or excellent (intraclass correlation coefficient >0.75), with 3-D reproducibility always better than 2-D. Axial rotation was present in all patients with a mean of 7.9° (SD 6.9). Although the differences between 2-D and 3-D measurements were small, 3-D evaluation enables the assessment of axial rotation and brings us closer to a routine 3-D evaluation of malunion.Level of evidence: III.

Three cases of posttraumatic wrist problems solved with 3D-printed patient-specific guides

Symptomatic malunion of the wrist is one of the most common posttraumatic wrist problems. This study demonstrates three patients with complex malunions of the wrist who benefited from a corrective osteotomy using preplanned 3D-printed patient-specific guides, by experiencing improvement in their wrist function, grip strength and a reduction in pain.

Accuracy of radiographic measurements of fracture-induced deformity in the distal radius

Background

Management of the distal radius fracture (DRF) is to some extent based on radiographic characterization of fracture displacement. It remains unclear, however, if the measurements used to quantify displacement are accurate.

Purpose

To quantify accuracy of two radiographic measurements: dorsal/volar tilt and fracture compression, measured indirectly as ulnar variance (UV), using radiostereometric analyses (RSA) as reference standard.

Material and Methods

Twenty-one fresh frozen non-fractured human cadaveric forearms (right = 11, left = 10) were thawed and eligible for inclusion. The forearms were mounted on a custom made platform that allowed for controlled forearm rotation, and they underwent two rounds of imaging (both rounds consisted of RSA and radiographs). In round one, the non-fractured forearms were radiographed. In round two, artificial DRF´s with compression and dorsal angulation were created and imaging procedures repeated. Change in tilt and UV between the non-fractured and later fractured forearms was defined as fracture-induced deformity. Deformity was measured radiographically and additionally calculated using RSA. Bland Altman analyses were used to estimate agreement between radiographically measured, and RSA calculated, fracture-induced deformity.

Results

Our results indicated that radiographs underestimate the amount of fracture-induced deformity. Mean measured differences (bias) in dorsal tilt deformity between radiographs and RSA were -2.5° for both observers. The corresponding values for UV were -1.4 mm and -1.5 mm.

Conclusion

Quantifying fracture-induced deformity on radiographs underestimated the actual deformity when compared to RSA calculated deformity. These findings suggest that clinicians, at least in part, base fracture management and potentially corrective surgery on inaccurate measurements.

Patient-Specific Guided Osteotomy to Correct a Symptomatic Malunion of the Left Forearm

We present a case report of a 12-year old female with a midshaft forearm fracture. Initial conservative treatment with a cast failed, resulting in a malunion. The malunion resulted in functional impairment for which surgery was indicated. A corrective osteotomy was planned using 3D analyses of the preoperative CT-scan. Subsequently, patient-specific guides were printed and used during the procedure to precisely correct the malunion. Three months after surgery, the radiographs showed full consolidation and the patient was pain-free with full range of motion and comparable strength in both forearms. The current case report shows that a corrective osteotomy with patient-specific guides based on preoperative 3D analyses can help surgeons to plan and precisely correct complex malunions resulting in improved functional outcomes.

Three-Dimensional Versus Radiographic Measurements for Analyzing Extra-Articular Distal Radius Malunion

PURPOSE

To compare the accuracy of evaluating deformity in distal radius malunions using plain radiographic measurements compared with a 3-dimensional method involving 3-dimensional computer bone models.

METHODS

Consecutive patients who had an extra-articular distal radius malunion were included. Standard radiographs and computed tomography scans of both wrists were performed. Palmar tilt, radial tilt, and ulnar variance were measured on radiographs. The computed tomography scan data were sent to a workstation and 3-dimensional bone surface models of the radius were created. The 3-dimensional palmar tilt, 3-dimensional radial tilt, 3-dimensional ulnar variance, and axial rotational deformity were calculated.

RESULTS

Thirteen patients, mean age 40 years (range, 22-57 years) were included. The 3 3-dimensional values were positively correlated with their corresponding radiographic values. Nevertheless, the 3-dimesional palmar tilt and 3-dimensional radial tilt values were slightly smaller than the radiographic palmar tilt and radial tilt. The quantitative difference between the 3-dimensional method and plain radiographs was on average 2° for the dorsal deformity group and 3° for the palmar deformity group. The 3-dimensional ulnar variance was significantly higher than the radiographic ulnar variance by an average of +1.3 mm for malunions with dorsal tilt and +0.6 mm for malunions with palmar tilt. The 3-dimensional method allowed us to measure the extent of the axial rotational deformity, which was 9° on average (range, 2° to 21°).

CONCLUSIONS

Despite small differences, measurements made on both plain radiographs and 3-dimensional computer bone models are accurate for evaluating the deformity in extra-articular distal radius malunions. Our 3-dimensional method seems to provide a more accurate measurement of ulnar variance, particularly for dorsally angulated cases, and is helpful for measuring rotational malalignment.

CLINICAL RELEVANCE

In this study, we found that either a 3-dimensional computer bone model or plain radiographs can be used as a benchmark to evaluate the deformity of extra-articular distal radius malunion. The 3-dimensional method can also be used to define axial rotational deformity.

[3D analysis and computer assisted reconstruction for scaphoid non-union]

The odd shape of the scaphoid is a challenge to our spatial sense. Computer assistance is of an unmatched value when reconstructing a non-united scaphoid: From CT data a true 3-D-model can be generated, fully interactive; thus it can be moved, manipulated and of course also printed for hands-on experience. Comparing the virtual 3-D-models of the nonunion with the healthy contralateral scaphoid, the exact amount of the deformity is calculated which allows for the planning of an anatomically precise reconstruction of the scaphoid shape. Finally, computer generated patient specific instruments will facilitate the implementation of this planning intraoperatively. This proceeding enables us to reconstruct the non-united scaphoid markedly more accurately and with this reliably normalize wrist kinematics. Meanwhile we have applied this technique successfully in more than 50 cases of scaphoid-nonunions presenting with significant deformity.

Understanding the Patterns of Deformity of Wrist Fractures Using Computer Analysis

Computer modeling of the wrist has followed other fields in the search for descriptive methods to understand the biomechanics of injury. Using patient-specific 3D computer models, we may better understand the biomechanics of wrist fractures in order to plan better care. We may better estimate fracture morphology and stability and evaluate surgical indications, design more adequate or effective surgical approaches and develop novel methods of therapy. The purpose of this review is to question the actual advances made in the understanding of wrist fractures using computer models.

Computer-assisted 3D preoperative planning of corrective osteotomy for extra-articular distal radius malunion: A 16-patient case series

The aim of this prospective study was to describe the surgical procedure and to report outcomes of computer-assisted 3D preoperative planning of corrective osteotomy for extra-articular distal radius malunions. Sixteen consecutive patients were enrolled. CT scans of both wrists were performed, and 3D bone surface models of the radii were created. Software was used to simulate the osteotomy and the reorientation of the distal radial articular surface. Patient-specific cutting and drilling guides for intraoperative guidance of the osteotomy as well as bone graft templates were also simulated. At a mean follow-up of 12 months (range 6-27) after surgery, pain was reduced from 3 to 0.3 at rest and 6.8 to 1.5 during effort according to a visual analog scale. The average wrist flexion-extension was 145° and pronation-supination was 155°. Grip strength was 91% of the contralateral side. All patients achieved primary bone union in a mean of 10 weeks (range, 7-18). Using our 3D analysis method, preoperative 3D values showed no significant difference with radiographic measurement. Moreover, there was no significant difference between the postoperative radiographic values in term of correction. This procedure provides satisfactory clinical and radiological results with minimal residual malalignment. LEVEL OF EVIDENCE: III.

Image-Based Comparison Between the Bilateral Symmetry of the Distal Radii Through Established Measures

PURPOSE

Anthropometric assessment of bony structures in the body is important for preoperative computer-aided surgery, implant design, finite element modeling, and biomechanical studies investigating joint structure and function. The use of the contralateral limb in surgery and clinical practice relies on the assumption that the right and left limbs of an individual are symmetric. Therefore, the purpose of this study was to quantify the bilateral symmetry of the bony structures of the distal radius using 3-dimensional (3D) computed tomography.

METHODS

We collected computed tomography images of 37 paired, fresh-frozen, healthy cadaveric male upper limbs (aged 75.4 ± 8.3 years). Three-dimensional reconstructed models were created using semiautomatic segmentation. Using the 3D models, we measured 3D radial inclination, 3D volar tilt, 3D radial height, medial volar cortical angle, middle volar cortical angle, and lateral volar cortical angle and compared them between sides.

RESULTS

There were no statistically significant differences measured between right and left distal radius in 37 paired wrists. Mean radial height was 12.81 mm (SD, 1.74 mm) on the left and 12.88 mm (SD, 1.72 mm) on the right. Mean volar tilt was 10.74° (SD, 3.74°) and 10.77° (SD, 3.19°) and radial inclination was 24.05° (SD, 2.63°) and 24.18° (SD, 3.41°) on the left and right, respectively. Mean volar cortical angle across the radius was 140.9° (SD, 7.9°) on the left and 140.1° (SD, 7.9°) on the right.

CONCLUSIONS

Direct bilateral comparison of the distal radius and wrist joints is useful to predict normal anatomy of the injured radius, because bilateral similarities exist.

CLINICAL RELEVANCE

This article provides a comprehensive list of measurements of the distal radius compared bilaterally using a 3D model. From this study, we found that the contralateral radius can be used as a benchmark with which to compare fracture reduction and to manage malunions during the preoperative planning of corrective osteotomies. It can also be used to define normal anatomy.

Three-Dimensional In Vivo Analysis of Malunited Distal Radius Fractures With Restricted Forearm Rotation

Malunited distal radius fractures (DRFs) occasionally restrict forearm rotation, but the underlying pathology remains unclear. We aimed to elucidate the mechanism of rotational restriction by retrospective analysis of 23 patients with unilateral malunited DRFs who presented restricted forearm rotation. We conducted computed tomography during forearm rotation on both sides. Three-dimensional (3D) bone surface models of the forearm were created, and 3D deformity of the distal radius, translation of the distal radius relative to the ulna, distal radioulnar joint (DRUJ) contact area, and estimated path length (EPL) of distal radioulnar ligaments (DRUL) during forearm rotation were evaluated. In total, 18 patients had dorsal angular deformities (DA group) and five had volar angular deformities (VA group). In the DA group, the closest point between the distal radius and ulna on DRUJ was displaced to the volar side during supination and pronation (p < 0.001); DRUJ contact area was not significantly different between the DA and normal groups. In bone-ligament model simulation, the EPL of dorsal DRUL was longer in the DA group than in the normal group (p < 0.001); opposite phenomena were observed in the VA group. In the DA group, translation of the distal radius in a volar direction relative to the ulna during pronation was impaired presumably due to dorsal DRUL tightness. Anatomical normal reduction of the distal radius by corrective osteotomy may improve forearm rotation by improving triangular fibrocartilage complex tightness and normalizing translation of the distal radius relative to the ulna. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1881-1891, 2019.

Use of three-dimensional technology for complications of upper limb fracture treatment

In malunion cases, restoration of anatomy is a key factor in obtaining a good functional outcome, but this can be technically very challenging.

Three-dimensional printed bone models can further improve understanding of the malunion pattern.

The use of three-dimensional (3D) computer planning, and the assembly of patient-specific instruments and implants, especially in complex deformities of the upper limb, allow accurate correction while reducing operation time, blood loss volume and radiation exposure during surgery.

One of the major disadvantages of the 3D technique is the additional cost because it requires specific computer software, a dedicated clinical engineer, and a 3D printer.

Further technical developments and clinical investigations are necessary to better define the added value and cost/benefit relationship of 3D in the treatment of complex fractures, non-unions, and malunions.

Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180074

Patient specific pointer tool for corrective osteotomy: Quality of symmetry based planning and case study of ulnar reconstruction surgery

Malunion after forearm fractures are described to appear in 2% to 10% of cases. Reconstructive surgeries ensure adequate anatomical repositioning. Their importance derives from the fact that malunion can often lead to severe pain as well as deformities causing loss of function and aesthetic issues not only in the forearm, but also the wrist and elbow joint. In this paper a clinical case will be presented using a Patient Specific Instrument (PSI) as navigational aid for reconstructive surgery after malunion of a proximal ulnar fracture combined with allograft surgery of the radial head and radial condyle due to chronic traumatic radial head luxation (Monteggia fracture). A planning method based on symmetry is described and evaluated on twelve Computed Tomographic (CT) data sets of intact forearms. The absolute point to point deviation at distal end of the ulnar styloid process was used as a characteristic value for accuracy evaluation. It is 7.9±4.9mm when using only the proximal end of the ulna for registration. The simulated change of ulnar variance is -1.4±1.9mm. Design and concept of the PSI are proven in a clinical trial.

Three-dimensional virtual planning of corrective osteotomies of distal radius malunions: a systematic review and meta-analysis

The purpose of this study was to summarize and evaluate results of three-dimensional (3D-) planned corrective osteotomies of malunited distal radius fractures. 3D-planning techniques provide the possibility to address 3D-deformity that conventional planning methods might not address. We systematically searched PubMed, EMBASE and the Cochrane library for studies that performed a 3D-planned corrective osteotomy on patients with a malunited distal radius fracture. Fifteen studies with a total of 68 patients were included in the analysis. In 96% of cases, the preoperatively present palmar tilt, radial inclination and ulnar variance showed statistically significant improvement postoperatively with restoration to within 5° or 2 mm of their normal values. Mean flexion–extension, pro-supination and grip strength showed statistically significant improvement (p < 0.05). Complications were reported in 11 out of 68 patients (16%). With the current advances in 3D printing technology, 3D-planned corrective osteotomies seem a promising technique in the treatment of complex distal radius malunions.

Level of evidence IV Systematic review of case series, Level IV.

Comparison of 2D radiography and a semi-automatic CT-based 3D method for measuring change in dorsal angulation over time in distal radius fractures

OBJECTIVE

The aim of the present study was to compare the reliability and agreement between a computer tomography-based method (CT) and digitalised 2D radiographs (XR) when measuring change in dorsal angulation over time in distal radius fractures.

MATERIALS AND METHODS

Radiographs from 33 distal radius fractures treated with external fixation were retrospectively analysed. All fractures had been examined using both XR and CT at six times over 6 months postoperatively. The changes in dorsal angulation between the first reference images and the following examinations in every patient were calculated from 133 follow-up measurements by two assessors and repeated at two different time points. The measurements were analysed using Bland-Altman plots, comparing intra- and inter-observer agreement within and between XR and CT.

RESULTS

The mean differences in intra- and inter-observer measurements for XR, CT, and between XR and CT were close to zero, implying equal validity. The average intra- and inter-observer limits of agreement for XR, CT, and between XR and CT were ± 4.4°, ± 1.9° and ± 6.8° respectively.

CONCLUSIONS

For scientific purpose, the reliability of XR seems unacceptably low when measuring changes in dorsal angulation in distal radius fractures, whereas the reliability for the semi-automatic CT-based method was higher and is therefore preferable when a more precise method is requested.

Computer-Assisted 3-Dimensional Reconstructions of Scaphoid Fractures and Nonunions With and Without the Use of Patient-Specific Guides: Early Clinical Outcomes and Postoperative Assessments of Reconstruction Accuracy

PURPOSE

To present results regarding the accuracy of the reduction of surgically reconstructed scaphoid nonunions or fractures using 3-dimensional computer-based planning with and without patient-specific guides.

METHODS

Computer-based surgical planning was performed with computed tomography (CT) data on 22 patients comparing models of the pathological and the opposite uninjured scaphoid in 3 dimensions. For group 1 (9 patients), patient-specific guides were designed and manufactured using additive manufacturing technology. During surgery, the guides were used to define the orientation of the reduced fragments. The scaphoids in group 2 (13 patients) were reduced with the conventional freehand technique. All scaphoids in both groups were fixed with a headless compression screw or K-wires, and all bone defects (except one) were filled with autologous bone grafts or vascularized grafts. Postoperative CT scans were acquired 2 or more months after the operations to monitor consolidation and compare the final result with the preoperative plan. The clinical results and accuracy of the reconstructions were compared.

RESULTS

In group 1, 8 of 9 scaphoids healed after 2 to 6 months, and partial nonunion after 9 months was observed in one patient. In group 2, 11 of 13 scaphoids healed between 2 and 34 months whereas 2 scaphoids did not consolidate. Comparison of the preoperative and postoperative 3-dimensional data revealed an average residual displacement of 7° (4° in flexion-extension, 4° in ulnar-radial deviation, and 3° in pronation-supination) in group 1. In group 2, residual displacement after surgery was 26° (22° in flexion-extension, 12° in ulnar-radial deviation, and 7° in pronation-supination). The difference in the accuracy of reconstruction was significant.

CONCLUSIONS

Although the scaphoid is small, patient-specific guides can be used to perform scaphoid reconstructions. When the guides were used, the reconstructions were significantly more anatomic compared with those resulting from the freehand technique.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Computer-assisted 3D planned corrective osteotomies in eight malunited radius fractures

In corrective osteotomy of the radius, detailed preoperative planning is essential to optimising functional outcome. However, complex malunions are not completely addressed with conventional preoperative planning. Computer-assisted preoperative planning may optimise the results of corrective osteotomy of the radius. We analysed the pre- and postoperative radiological result of computer-assisted 3D planned corrective osteotomy in a series of patients with a malunited radius and assessed postoperative function. We included eight patients aged 13–64 who underwent a computer-assisted 3D planned corrective osteotomy of the radius for the treatment of a symptomatic radius malunion. We evaluated pre- and postoperative residual malpositioning on 3D reconstructions as expressed in six positioning parameters (three displacements along and three rotations about the axes of a 3D anatomical coordinate system) and assessed postoperative wrist range of motion. In this small case series, dorsopalmar tilt was significantly improved (p = 0.05). Ulnoradial shift, however, increased by the correction osteotomy (6 of 8 cases, 75 %). Postoperative 3D evaluation revealed improved positioning parameters for patients in axial rotational alignment (62.5 %), radial inclination (75 %), proximodistal shift (83 %) and volodorsal shift (88 %), although the cohort was not large enough to confirm this by statistical significance. All but one patient experienced improved range of motion (88 %). Computer-assisted 3D planning ameliorates alignment of radial malunions and improves functional results in patients with a symptomatic malunion of the radius. Further development is required to improve transfer of the planned position to the intra-operative bone.

Level of evidence IV.

Postoperative accuracy analysis of three-dimensional corrective osteotomy for cubitus varus deformity with a custom-made surgical guide based on computer simulation

BACKGROUND

For correction of cubitus varus deformity resulting from supracondylar fracture of the humerus, we developed an operative method with use of a custom-made surgical guide, designed on the basis of 3-dimensional (3D) computer simulation with computed tomography data. The purpose of this study was to investigate the postoperative accuracy of this system in clinical cases.

METHODS

Subjects included 17 consecutive patients (13 males and 4 females) with cubitus varus deformity after supracondylar fracture. Patients underwent 3D corrective osteotomy with use of a custom-made surgical guide. Postoperative computed tomography scan was performed after bone union diagnosis on plain radiographs, and postoperative 3D bone models were compared with preoperative simulation by surface registration technique. In addition, we evaluated radiographic parameters (humerus-elbow-wrist angle and tilting angle) and range of elbow motion at the most recent follow-up.

RESULTS

Mean errors in 3D corrective osteotomy were 0.6° ± 0.7° in varus-valgus rotation, 0.8° ± 1.3° in flexion-extension rotation, 2.9° ± 2.8° in internal-external rotation, 1.7 ± 1.8 mm in anterior-posterior translation, 1.3 ± 1.8 mm in lateral-medial translation, and 7.1 ± 6.3 mm in proximal-distal translation. The mean humerus-elbow-wrist angle on plain radiographs of the affected side was 15° in varus before surgery and improved to 6° in valgus after surgery. The mean tilting angle of the affected side was 31° before surgery and improved to 40° after surgery.

CONCLUSION

The 3D correction of cubitus varus deformity was performed accurately within the allowable error limits.

Ulnar shortening osteotomy for malunited distal radius fractures: results of a 7-year follow-up with special regard to the grade of radial displacement and post-operative ulnar variance

INTRODUCTION

The treatment of ulnar-sided wrist pain after malunited distal radius fractures remains controversial. Radial corrective osteotomy can restore congruity in the distal radioulnar joint (DRUJ) as well as adequate length of the radius. Ulnar shortening osteotomies leave the radius' angular deformities unchanged, risking secondary DRUJ osteoarthritis. We supposed that, even within the widely accepted limit of 20°, a greater angulation of the radius in the sagittal plane correlates with a higher rate of DRUJ osteoarthritis. Furthermore, we suspected worse results from an ulna shortened to a negative rather than a neutral or positive ulnar variance.

MATERIALS AND METHODS

For this retrospective study, we reviewed 23 patients a mean 7.2 (range 5.6-8.5) years after ulnar shortening osteotomy for malunion of distal radius fractures. We compared 14 patients with up to 10° dorsal or palmar displacement from the normal palmar tilt of 10° to 9 patients with more than 10° displacement, and 15 patients whose post-operative ulnar variance was neutral or positive to 8 who had a negative one.

RESULTS

Ulnar-sided wrist pain decreased enough to satisfy 21 of the 23 patients. Clinical results tended to be better when radial displacement was minor and when post-operative ulnar variance was positive or neutral. A shorter ulna significantly increased the rate of DRUJ osteoarthritis, whereas a greater degree of radial displacement only increased the rate slightly.

CONCLUSIONS

Radial corrective osteotomy should be discussed as alternative when displacement of the radius in the sagittal plane exceeds 10°. The ulna should be shortened moderately to reduce the risk of osteoarthritis in the distal radioulnar joint.

Three-dimensional corrective osteotomy using a patient-specific osteotomy guide and bone plate based on a computer simulation system: accuracy analysis in a cadaver study

BACKGROUND

The accuracy of three-dimensional (3-D) corrective osteotomy using a patient-specific osteotomy guide and bone plate based on computer simulation was investigated.

METHODS

Six fresh-frozen cadaver upper limbs were used. A patient-specific osteotomy guide designed to realize a preplanned osteotomy was set on the distal humerus and distal radius, and the error in the setting location was evaluated. After the osteotomy, the surgical site was fixed using a patient-specific bone plate designed to exactly fit the anatomical shape of the postoperative bone model. The postoperative results were compared with the preoperative simulation.

RESULTS

The errors in the guide location on the humerus and radius were <1.5° and 1.0 mm and <1.0° and 1.0 mm, respectively. The plate fixation errors of the humerus and radius were <2.0° and 1.5 mm and <1.0° and 1.0 mm, respectively.

CONCLUSIONS

The system is sufficiently feasible to realize precise 3-D deformity correction of a limb.

3-Dimensional deformity analysis of malunited forearm diaphyseal fractures

PURPOSE

Several biomechanical studies using cadavers have revealed that axial rotation deformity of the forearm bones reduces forearm motion. However, little information is available on the 3-dimensional deformity patterns, including axial rotation deformity in malunited diaphyseal fractures of the forearm. The complex deformity of both forearm bones is difficult to assess on plain radiographs or cross-sectional images. Therefore, we assessed osseous deformity in malunited diaphyseal fractures of the forearm using 3-dimensioinal analysis.

METHODS

We examined 21 patients (16 malunions of both forearm bones and 5 isolated radial malunions). Three-dimensional computer models of bilateral radius and ulna were created from computed tomography data. We evaluated deformity by superimposing the mirror-image bone model of the contralateral normal bone onto a model of the affected bone.

RESULTS

In 21 radial malunions, extension (n = 17) and pronation (n = 16) deformities were common. This tendency was seen particularly in proximal malunions. Average extension, valgus, and pronation deformities were 18°, 2°, and 16°, respectively. In 16 ulnar malunions, valgus (n = 15) and pronation (n = 12) deformities were common. Average flexion, valgus, and pronation deformities were 1°, 11°, and 6°, respectively. Extension deformity of the radius and valgus deformity of the ulna were correlated with restriction of forearm motion.

CONCLUSIONS

Malunited diaphyseal fractures of both forearm bones showed complex deformities, which suggests that 3-dimensional modeling may be a more effective method than standard computed tomography or radiographs. Pronation deformity of the radius may be caused by the supinator and pronator muscles. In addition, the deformity pattern of both bones may indicate that valgus and internal rotation force in the neutral forearm position is applied to both forearm bones after injury.

CLINICAL RELEVANCE

Three-dimensional forearm osteotomy, including rotational realignment, is necessary to obtain anatomical reduction.