Computed tomography for suspected scaphoid fractures: comparison of reformations in the plane of the wrist versus the long axis of the scaphoid

Incidence and underreporting of osseous wrist and hand injuries on whole-body computed tomographies at a level 1 trauma center

BACKGROUND

To investigate the incidence of osseous wrist and hand injuries on whole-body computed tomographies (WBCT) at an urban maximum-care trauma center, to report the number of missed cases in primary radiology reports, and to develop an algorithm for improved detection of these injuries.

METHODS

Retrospective analysis reviewing all WBCT for a period of 8 months for osseous wrist and hand injuries. (1) Reconstruction of hands/wrists in three planes (thickness 1-2 mm) and analysis by a blinded musculoskeletal radiologist. (2) Scanning of primary radiology reports and comparison to the re-evaluation. (3) Calculation of the diagnostic accuracy of WBCT during primary reporting. (4) Search for factors potentially influencing the incidence (trauma mechanism, associated injuries, Glasgow Coma Scale, artifacts). (5) Development of an algorithm to improve the detection rate.

RESULTS

Five hundred six WBCT were included between 01/2020 and 08/2020. 59 (11.7%) WBCT showed 92 osseous wrist or hand injuries. Distal intra-articular radius fractures occurred most frequently (n = 24, 26.1%); 22 patients (37.3%) showed multiple injuries. The sensitivity of WBCT in the detection of wrist and hand fractures during primary evaluation was low with 4 positive cases identified correctly (6.8%; 95% CI 1.9 to 16.5), while the specificity was 100% (95% CI 99.2 to 100.0). Forty-three cases (72.9%) were detected on additional imaging after clinical reassessment. Twelve injuries remained undetected (20.3%). Motorcycle accidents were more common in positive cases (22.0% vs. 10.1%, p = 0.006). 98% of positive cases showed additional fractures of the upper and/or lower extremities, whereas 37% of the patients without osseous wrist and hand injuries suffered such fractures (p < 0.001). The remaining investigated factors did not seem to influence the occurrence.

CONCLUSION

Osseous wrist and hand injuries are present in 11.7% on WBCT after polytrauma. 93.2% of injuries were missed primarily, resulting in a very low sensitivity of WBCT during primary reporting. Motorcycle accidents might predispose for these injuries, and they often cause additional fractures of the extremities. Clinical re-evaluation of patients and secondary re-evaluation of WBCT with preparation of dedicated multiplanar reformations are essential in polytrauma cases to detect osseous injuries of wrist and hand reliably.

TRIAL REGISTRATION

The study was registered prospectively on November 17th, 2020, at the German register for clinical trials (DRKS-ID: DRKS00023589 ).

Can CT-Scan Measurements of Humpback Deformity, Dislocation, and the Size of Bony Cysts Predict Union after Surgery for Scaphoid Nonunion?

Objective  Scaphoid fractures are associated with high rates of late- or nonunion after conservative treatment. Nonunion is reported to occur in approximately 10% of all scaphoid fractures. It is known that the union of scaphoid fractures is affected by factors such as location at proximal pole, tobacco smoking, and the time from injury to treatment. Same factors seem to affect the healing after surgery for scaphoid nonunion. While the impact of preoperative humpback deformity on the functional outcome after surgery has been previously reported, the impact of humpback deformity, displacement, and the presence of bony cysts on union rate and time to healing after surgery has not been studied. Purpose  The primary purpose of this study is to assess the association of humpback deformity, fragment displacement, and the size of cysts along the fracture line with the union rate and union time, following surgery of scaphoid nonunion. The second purpose of the study is to investigate the interobserver reliability in the evaluation of computed tomography (CT) scans of scaphoid nonunion. Patients and Methods  From January 2008 to December 2018, 178 patients were surgically treated in our institution. After exclusion criteria were met, 63 patients with scaphoid delayed- or established nonunion, and preoperative CT scans of high quality (<2mm./ slice), were retrospectively analyzed. There was 58 men and 5 women with a mean age of 30 years (range: 16-72 years). Four orthopaedic surgeons and one radiologist independently analyzed the CT scans. The dorsal cortical angle (DCA), lateral intrascaphoid angle (LISA), the height-to-length ratio, the size of the cysts, and displacement of the fragments were measured. Healing was defined by CT scan, or by conventional X-ray, and status of no pain at clinical examination. Thirty-two of the patients had developed nonunion (>6 months postinjury), while 31 were in a stage of delayed union (3-6 months postinjury). Results  Open surgery with cancellous or structural bone graft was the treatment of choice in 49 patients, 8 patients were treated with arthroscopic bone grafting, and 6 patients with delayed union were operated with percutaneous screw fixation, without bone graft. Overall union rate was 86% (54/63) and was achieved after 84 days (12 weeks) (mean). The failure rate and time to healing were not associated with the degree of the humpback deformity, size of the cysts, or displacement of the nonunion in general. However, greater dislocation, and the localization of the nonunion at the scaphoid waist, showed significant influence on the union rate. Dislocation at nonunion site, in the group of the patients who united after surgery, was 2.7 mm (95% confidence interval [CI]: 1.5-3.7), and in the group who did not unite was 4.2 mm (95% CI: 2.9-5.7); p  = 0.048). Time from injury to surgery was significantly correlated with time to union ( p  < 0.05), but not associated with the union rate ( p  < 0.4). Patients treated arthroscopically achieved faster healing (42 days), (standard deviation [SD]: 22.27) as compared with patients treated by open techniques (92 days; SD: 70.86). Agreement among five observers calculated as intraclass correlation coefficient was for LISA: 0.92; for height-to-length ratio: 0.73; for DCA: 0.65; for size of cysts: 0.61; and for displacement in millimeters: 0.24, respectively. Conclusions  The degree of humpback deformity and the size of cysts along the fracture line of scaphoid nonunion have no predictive value for the result, neither for the union rate nor the union time after surgery for the scaphoid nonunion. However, larger dislocation of the fragments measured at the scaphoid waist showed lower union rate. Time to healing following surgery is mainly influenced by the time from injury to the surgical treatment and may be influenced by the choice of the surgical technique. Interrater reliability calculation was best with LISA measurements, and worse with the measurements of the dislocation. Level of Evidence  This is a Level III, observational, case-control study.

The effect of reformatting axis of computed tomography scans on the measurement of deformities in scaphoid waist nonunion

BACKGROUND

Computed tomography (CT) has been used to understand the deformity of scaphoid nonunion, but no standard protocol for the reformatting of scaphoid CT imaging exists. The purpose of this study was to compare the reliability of measurements of the deformity of scaphoid waist nonunion between CT-scans reformatted in line with the scaphoid long axis and CT-scans reformatted in line with the wrist axis.

HYPOTHESIS

We hypothesized that CT-scan which was reformatted along the scaphoid long axis is more reliable for understanding the deformity of scaphoid waist nonunion.

PATIENTS AND METHODS

CT-scans of 28 wrists with a scaphoid waist nonunion were reformatted along both the long axis of the scaphoid and of the wrist. For each set of CT-scans, the nonunion gap in axial, coronal and sagittal series, the intrascaphoid angle, and the height to length ratio were measured. All scans were reviewed twice by three observers and intraclass correlation coefficients (ICCs) for inter- and intraobserver reliability were assessed.

RESULTS

For the measurement of nonunion gaps and height to length ratio, neither inter- nor intraobserver reliability showed significant differences between the two reformatting scans. However, for the intrascaphoid angle, both inter- (ICC: 0.202 vs. 0.419, p<0.001) and intraobserver (ICC: 0.614 vs. 0.790, p<0.001) reliability were significantly higher on scaphoid axis CT-scan than on wrist axis CT-scan.

DISCUSSION

In the assessment of deformity in patients with scaphoid waist nonunion, scaphoid axis reformatting CT-scans showed superior reliability for the measurement of intrascaphoid angle than did wrist axis reformatting CT-scans. Although there are several limitations for the correct assessment of all three-dimensional deformity, scaphoid axis reformatting CT-scans could help in assessing the extent of humpback deformity in patients with scaphoid waist nonunion.

LEVEL OF EVIDENCE

IV; diagnostic.

Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures

Background  Scaphoid fracture accounts for approximately 15% of acute wrist fractures. Clinical examination and plain X-rays are commonly used to diagnose the fracture, but this approach may miss up to 16% of fractures in the absence of clear-cut lucent lines on plain radiographs. As such, additional imaging may be required. It is not clear which imaging modality is the best. The goal of this study is to summarize the current literature on scaphoid fractures to evaluate the sensitivity, specificity, and accuracy of four different imaging modalities. Case Description  A systematic-review and meta-analysis was performed. The search term "scaphoid fracture" was used and all prospective articles investigating magnetic resonance imaging (MRI), computed tomography (CT), bone scintigraphy, and ultrasound were included. In total, 2,808 abstracts were reviewed. Of these, 42 articles investigating 51 different diagnostic tools in 2,507 patients were included. Literature Review  The mean age was 34.1 ± 5.7 years, and the overall incidence of scaphoid fractures missed on X-ray and diagnosed on advanced imaging was 21.8%. MRI had the highest sensitivity and specificity for diagnosing scaphoid fractures, which were 94.2 and 97.7%, respectively, followed by CT scan with a sensitivity and specificity at 81.5 and 96.0%, respectively. The sensitivity and specificity of ultrasound were 81.5 and 77.4%, respectively. Significant differences between MRI, bone scintigraphy, CT, and ultrasound were identified. Clinical Relevance  MRI has higher sensitivity and specificity than CT scan, bone scintigraphy, or ultrasound. Level of Evidence  This is a Level II systematic review.

Diagnostic accuracy of history taking, physical examination and imaging for phalangeal, metacarpal and carpal fractures: a systematic review update

Background

The standard diagnostic work-up for hand and wrist fractures consists of history taking, physical examination and imaging if needed, but the supporting evidence for this work-up is limited. The purpose of this study was to systematically examine the diagnostic accuracy of tests for hand and wrist fractures.

Methods

A systematic search for relevant studies was performed. Methodological quality was assessed and sensitivity (Se), specificity (Sp), accuracy, positive predictive value (PPV) and negative predictive value (NPV) were extracted from the eligible studies.

Results

Of the 35 eligible studies, two described the diagnostic accuracy of history taking for hand and wrist fractures. Physical examination with or without radiological examination for diagnosing scaphoid fractures (five studies) showed Se, Sp, accuracy, PPV and NPV ranging from 15 to 100%, 13–98%, 55–73%, 14–73% and 75–100%, respectively. Physical examination with radiological examination for diagnosing other carpal bone fractures (one study) showed a Se of 100%, with the exception of the triquetrum (75%). Physical examination for diagnosing phalangeal and metacarpal fractures (one study) showed Se, Sp, accuracy, PPV and NPV ranging from 26 to 55%, 13–89%, 45–76%, 41–77% and 63–75%, respectively.

Imaging modalities of scaphoid fractures showed predominantly low values for PPV and the highest values for Sp and NPV (24 studies). Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasonography (US) and Bone Scintigraphy (BS) were comparable in diagnostic accuracy for diagnosing a scaphoid fracture, with an accuracy ranging from 85 to 100%, 79–100%, 49–100% and 86–97%, respectively. Imaging for metacarpal and finger fractures showed Se, Sp, accuracy, PPV and NPV ranging from 73 to 100%, 78–100%, 70–100%, 79–100% and 70–100%, respectively.

Conclusions

Only two studies were found on the diagnostic accuracy of history taking for hand and wrist fractures in the current review. Physical examination was of moderate use for diagnosing a scaphoid fracture and of limited use for diagnosing phalangeal, metacarpal and remaining carpal fractures. MRI, CT and BS were found to be moderately accurate for the definitive diagnosis of clinically suspected carpal fractures.

Managing the Athlete with a Scaphoid Fracture

Most minimally displaced scaphoid fractures and all displaced scaphoid fractures in elite athletes are treated with early fixation to maximally expedite the return to full function. Computed tomographic (CT) scans are recommended in all scaphoid fractures to facilitate a complete understanding of fracture anatomy and to allow for optimal screw placement. Screw placement is important to maximize healing capacity of the fracture and allow for return to sport. Postoperative CT scans can be helpful to evaluate the extent of healing and may allow patients to return to play sooner.

The Effect of Computed Tomography Scans Oriented Along the Longitudinal Scaphoid Axis on Measurements of Deformity and Displacement in Scaphoid Fractures

PURPOSE

Reformatting computed tomography (CT) scans along the scaphoid longitudinal axis improves the ability to detect scaphoid fractures compared with reformats along the wrist axis. However, it remains unclear whether scaphoid axis reformats affect measurements of displacement or deformity, which are factors that drive the clinical decision to perform open reduction internal fixation. Our null hypothesis was that reformatting CT scans along the scaphoid axis does not affect measurements of fracture displacement and deformity.

METHODS

Thirty patients with CT scans demonstrating scaphoid fractures (4 proximal pole, 17 midwaist fractures, and 9 distal) were identified and reformatted along 2 axes: the longitudinal axis of the scaphoid and the longitudinal axis of the wrist. The reformatted scans were sent to 2 musculoskeletal radiologists and 2 orthopedic hand surgeons who made the following measurements: (1) fracture gap, (2) displacement of the articular surface, (3) intrascaphoid angle, and (4) height to length (H:L) ratio.

RESULTS

The reliability of each of the measurements cited above was compared for all raters between the 2 axes using intraclass correlation coefficients. Measurement of fracture gap and articular displacement trended toward more reliability in the wrist axis, whereas measurement of H:L ratio and intrascaphoid angle trended toward more reliability in the scaphoid axis. However, no differences in measurements between the 2 axes were statistically significant.

CONCLUSIONS

This study demonstrates that reformatting CT scans in line with the axis of the scaphoid does not result in more reliable measurements of displacement or deformity.

CLINICAL RELEVANCE

Measurements of displacement and deformity in scaphoid fractures can be made in the wrist axis with comparative reliability to those in the longitudinal scaphoid axis.

Is there a trend in CT scanning scaphoid nonunions for deformity assessment?-A systematic review

PURPOSE

The effect of scaphoid nonunion deformity on wrist function is uncertain due to the lack of reliable imaging tools. Advanced three-dimensional (3-D) computed tomography (CT)-based imaging techniques may improve deformity assessment by using a mirrored image of the contralateral intact wrist as anatomic reference. The implementation of such techniques depends on the extent to which conventional CT is currently used in standard practice. The purpose of this systematic review of medical literature was to analyze the trend in CT scanning scaphoid nonunions, either unilaterally or bilaterally.

MATERIALS AND METHODS

Using Medline and Embase databases, two independent reviewers searched for original full-length clinical articles describing series with at least five patients focusing on reconstructive surgery of scaphoid nonunions with bone grafting and/or fixation, from the years 2000-2015. We excluded reports focusing on only nonunions suspected for avascular necrosis and/or treated with vascularized bone grafting, as their workup often includes magnetic resonance imaging. For data analysis, we evaluated the use of CT scans and distinguished between uni- and bilateral, and pre- and postoperative scans.

RESULTS

Seventy-seven articles were included of which 16 were published between 2000 and 2005, 19 between 2006 and 2010, and 42 between 2011 and 2015. For these consecutive intervals, the rates of articles describing the use of pre- and postoperative CT scans increased from 13%, to 16%, to 31%, and from 25%, to 32%, to 52%, respectively. Hereof, only two (3%) articles described the use of bilateral CT scans.

CONCLUSION

There is an evident trend in performing unilateral CT scans before and after reconstructive surgery of a scaphoid nonunion. To improve assessment of scaphoid nonunion deformity using 3-D CT-based imaging techniques, we recommend scanning the contralateral wrist as well.

Cone-Beam CT in diagnosis of scaphoid fractures

OBJECTIVE

This prospective study investigated the sensitivity of cone beam computed tomography (CBCT), a low dose technique recently made available for extremity examinations, in detecting scaphoid fractures. Magnetic resonance imaging (MRI) was used as gold standard for scaphoid fractures.

MATERIALS AND METHODS

A total of 95 patients with a clinically suspected scaphoid fracture were examined with radiography and CBCT in the acute setting. A negative CBCT exam was followed by an MRI within 2 weeks. When a scaphoid fracture was detected on MRI a new CBCT was performed.

RESULTS

Radiography depicted seven scaphoid fractures, all of which were also seen with CBCT. CBCT detected another four scaphoid fractures. With MRI another five scaphoid fractures were identified that were not seen with radiography or with CBCT. These were also not visible on the reexamination CBCT. Sensitivity for radiography was 44, 95 % confidence interval 21-69 %, and for CBCT 69 %, 95 % confidence interval 41-88 % (p = 0.12). Several non-scaphoid fractures in the carpal region were identified, radiography and CBCT depicted 7 and 34, respectively (p < 0.0001).

CONCLUSION

CBCT is a superior alternative to radiography, entailing more accurate diagnoses of carpal region fractures, and thereby requiring fewer follow-up MRI examinations. However, CBCT cannot be used to exclude scaphoid fractures, since MRI identified additional occult scaphoid fractures.

6-week radiographs unsuitable for diagnosis of suspected scaphoid fractures

INTRODUCTION

Six week follow-up radiographs are a common reference standard for the diagnosis of suspected scaphoid fractures. The main purpose of this study was to evaluate the interobserver reliability and diagnostic performance characteristics of 6-weeks radiographs for the detection of scaphoid fractures. In addition, two online techniques for evaluating radiographs were compared.

MATERIALS AND METHODS

A total of 81 orthopedic surgeons affiliated with the Science of Variation Group assessed initial and 6-week scaphoid-specific radiographs of a consecutive series of 34 patients with suspected scaphoid fractures. They were randomized in two groups for evaluation, one used a standard website showing JPEG files and one a more sophisticated image viewer (DICOM). The goal was to identify the presence or absence of a (consolidated) scaphoid fracture. Interobserver reliability was calculated using the multirater kappa measure. Diagnostic performance characteristics were calculated according to standard formulas with CT and MRI upon presentation in the emergency department as reference standards.

RESULTS

The interobserver agreement of 6-week radiographs for the diagnosis of scaphoid fractures was slight for both JPEG and DICOM (k = 0.15 and k = 0.14, respectively). The sensitivity (range 42-79 %) and negative predictive value (range 79-94 %) were significantly higher using a DICOM viewer compared to JPEG images. There were no differences in specificity (range 53-59 %), accuracy (range 53-58 %), and positive predictive value (range 14-26 %) between the groups.

CONCLUSIONS

Due to low agreement between observers for the recognition of scaphoid fractures and poor diagnostic performance, 6-week radiographs are not adequate for evaluating suspected scaphoid fractures. The online evaluation of radiographs using a DICOM viewer seem to improve diagnostic performance characteristics compared to static JPEG images and future reliability and diagnostic studies should account for variation due to the method of delivering medical images.

LEVEL OF EVIDENCE

Diagnostic level II.

Measurement of the radiographic anatomy of the small and ring metacarpals using computerized tomographic scans

BACKGROUND

To date, only plain radiographic definitions of normal anatomical parameters have been described. Our study aims to describe normal anatomic measurements of small and ring metacarpals using a novel digital reconstruction technique based on raw CT image data. We hypothesize that current plain radiographic data incorrectly describes normal metacarpal anatomy in the lateral plane.

METHODS

Thirty-five scans of the small and 30 scans of the ring metacarpals form the basis for this study. Using a custom digital 3D image reformatting software, CT sections were reconstructed in the plane of each studied metacarpal. The 3D images were converted to sagittal and coronal weighted projections to represent lateral and posteroanterior (PA) 2D images that are equivalent to "perfect orthogonal" radiographs. Using a customized image measurement program, shaft lengths, shaft-bending angle (SBA), and capital-axis angle (CAA) were measured.

RESULTS

Our results show that CAA averaged 14 and 12° in the ring and small metacarpals, respectively. Apex dorsal SBA averaged 12 and 10° in the ring and small metacarpals, respectively. On the PA images, the shafts are nearly straight. In contrast to prior reported values, we found the CAA to be less acute and the metacarpal curvature less pronounced on the lateral projection. We also demonstrated that much of the metacarpal apex dorsal bend is in the shaft itself.

CONCLUSION

Normal anatomic parameters of metacarpals are based primarily on radiographic data, and as such are limited due to bony overlap in the lateral plane, as well as imperfect radiographic projections that are known to distort anatomical relationships. This novel method of image reconstruction eliminates metacarpal overlap and defines precise anatomical reference for metacarpals.

Diagnosis of Occult Scaphoid Fractures: A Cost-Effectiveness Analysis

BACKGROUND

Scaphoid fractures are common but may be missed on initial radiographs. Advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) have improved diagnostic accuracy, but at an increased initial cost. The purpose of this study was to evaluate the cost-effectiveness of immediate advanced imaging for suspected occult scaphoid fractures.

METHODS

A decision analysis model was created to evaluate three diagnostic strategies for patients with concerning history and examination but negative radiographs: (1) empiric cast immobilization with orthopaedic follow-up and repeat radiography at two weeks post-injury, (2) immediate CT scanning, or (3) immediate MRI. Prevalence of occult scaphoid fracture, sensitivity and specificity of CT and MRI, and risks and outcomes of a missed fracture were derived from published clinical trials. Costs of imaging, lost worker productivity, and surgical costs of nonunion surgery were estimated on the basis of the literature.

RESULTS

Advanced imaging was dominant over empiric cast immobilization; advanced imaging had lower costs and its health outcomes were projected to be better than those of empiric cast immobilization. MRI was slightly more cost-effective than CT on the basis of the mean published diagnostic performance, but was highly sensitive to test performance characteristics. Advanced imaging would have to increase in cost to more than $2000 or decrease in sensitivity to <25% for CT or <32% for MRI for empiric cast immobilization to be cost-effective.

CONCLUSIONS

Given its relatively low cost and high diagnostic accuracy, advanced imaging for suspected scaphoid fractures in the setting of negative radiographs represents a cost-effective strategy for reducing both costs and morbidity. The decision to use CT compared with MRI is a function of individual institutional costs and local test performance characteristics.