Both scanning plane and observer affect measurements of scaphoid deformity

Scaphoid Malunion: Incidence, Predictors, and Outcomes

Background  Scaphoid malunion is rarely reported. Previous literature has attributed loss of carpal height and degenerative changes to scaphoid malunion, but the percentage of asymptomatic malunions remains unknown. Purpose  The authors of this study aim to define predictors of malunion and outcomes associated with scaphoid malunion. Methods  Institutional board review was obtained prior to evaluating medical records of patients 18 years and older who were treated for scaphoid fractures and/or nonunion between 2000 and 2020. The following data were collected for each patient: age, gender, fracture location, surgical technique, time to union, and whether malunion resulted. Malunion was defined using a lateral intrascaphoid angle (LISA) >45 degrees and height-to-length ratio (HLR) >60. Pain scores, range of motion (ROM), and secondary surgery were also evaluated. Results  Overall, 355 scaphoid injuries, including 196 acute fractures and 159 nonunions, were evaluated in this analysis. Of these, 55 scaphoids (15%) met the definition of malunion. Of these patients, 23% were female. The mean age at the time of injury was 29 years. Nonunion cases were more likely than acute cases to be associated with malunion. Proximal pole fractures were more likely to associated with malunion than waist fractures. When controlling for nonunion and fracture location, malunited scaphoids were not associated with any significant difference in pain score, ROM, or secondary surgery, compared with nonmalunion cases. A total of 10 patients (3.3%) without malunion and 2 patients (3.6%) with malunion went on to a secondary surgery. Final extension/flexion was 67/67 degrees and 56/59 degrees in nonmalunion and malunion groups, respectively, but these differences were not significant. Conclusion  Compared with scaphoid injuries that do not result in malunion, scaphoid injuries that heal into malunion have similar outcomes. While scaphoid malunion in a single case or series may be associated with poor outcomes, this study suggests that scaphoid malunions do not have worse functional outcomes. Level of Evidence  This is a Level IV study.

Residual flexion deformity after scaphoid nonunion surgery: 7-year follow-up study

The clinical implication of a residual flexion deformity following surgery for scaphoid nonunion is unclear. Sixty-three patients who underwent scaphoid nonunion surgery were assessed after a mean of 7 years (range 5-10) to analyse the outcomes based on the presence of residual scaphoid deformity. Primary outcome was Disabilities of the Arm, Shoulder and Hand score. Secondary outcomes were Patient-Rated Wrist Evaluation score, wrist range of motion and strength. Patients were dichotomized to residual deformity or no deformity. Scaphoid deformity was calculated from CT scans based on the median difference between the height-length ratio of the operated versus the uninjured scaphoid. There were no differences between residual deformity (n = 33) and no deformity (n = 30) in any outcome variables, except for wrist extension which was slightly worse in the deformity group. The deformity group had a greater number of radiographic osteoarthritis, but all cases were mild, and osteoarthritis did not correlate to a worse outcome. We conclude that residual scaphoid deformity has no relevant negative impact on mid-term wrist function.Level of evidence: IV.

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.

Surgical fixation compared with cast immobilisation for adults with a bicortical fracture of the scaphoid waist: the SWIFFT RCT

BACKGROUND

Scaphoid fractures account for 90% of carpal fractures and occur predominantly in young men. Immediate surgical fixation of this fracture has increased.

OBJECTIVE

To compare the clinical effectiveness and cost-effectiveness of surgical fixation with cast treatment and early fixation in adults with scaphoid waist fractures that fail to unite.

DESIGN

Multicentre, pragmatic, open-label, parallel two-arm randomised controlled trial with an economic evaluation and a nested qualitative study.

SETTING

Orthopaedic departments of 31 hospitals in England and Wales recruited from July 2013, with final follow-up in September 2017.

PARTICIPANTS

Adults (aged ≥ 16 years) presenting within 2 weeks of injury with a clear, bicortical fracture of the scaphoid waist on plain radiographs.

INTERVENTIONS

Early surgical fixation using Conformité Européenne-marked headless compression screws. Below-elbow cast immobilisation for 6-10 weeks and urgent fixation of confirmed non-union.

MAIN OUTCOME MEASURES

The primary outcome and end point was the Patient-Rated Wrist Evaluation total score at 52 weeks, with a clinically relevant difference of 6 points. Secondary outcomes included Patient-Rated Wrist Evaluation pain and function subscales, Short Form questionnaire 12-items, bone union, range of movement, grip strength, complications and return to work.

RESULTS

The mean age of 439 participants was 33 years; 363 participants were male (83%) and 269 participants had an undisplaced fracture (61%). The primary analysis was on 408 participants with valid Patient-Rated Wrist Evaluation outcome data for at least one post-randomisation time point (surgery, n = 203 of 219; cast, n = 205 of 220). There was no clinically relevant difference in the Patient-Rated Wrist Evaluation total score at 52 weeks: the mean score in the cast group was 14.0 (95% confidence interval 11.3 to 16.6) and in the surgery group was 11.9 (95% confidence interval 9.2 to 14.5), with an adjusted mean difference of -2.1 in favour of surgery (95% confidence interval -5.8 to 1.6; p = 0.27). The non-union rate was low (surgery group, n = 1; cast group, n = 4). Eight participants in the surgery group had a total of 11 reoperations and one participant in the cast group required a reoperation for non-union. The base-case economic analysis at 52 weeks found that surgery cost £1295 per patient more (95% confidence interval £1084 to £1504) than cast treatment. The base-case analysis of a lifetime-extrapolated model confirmed that the cast treatment pathway was more cost-effective. The nested qualitative study identified patients' desire to have a 'sense of recovering', which surgeons should address at the outset.

LIMITATION

There were 17 participants who had initial cast treatment and surgery for confirmed non-union, which in 14 cases was within 6 months from randomisation and in three cases was after 6 months. Three of the four participants in the cast group who had a non-union at 52 weeks were not offered surgery.

CONCLUSIONS

Adult patients with an undisplaced or minimally displaced scaphoid waist fracture should have cast immobilisation and suspected non-unions immediately confirmed and urgently fixed. Patients should be followed up at 5 years to investigate the effect of partial union, degenerative arthritis, malunion and screw problems on their quality of life.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN67901257.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 52. See the NIHR Journals Library website for further project information.

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.

Normal ranges for measurements of the scaphoid bone from sagittal computed tomography images

This study aimed to determine normal values of three parameters commonly used to determine malunion by investigating intact scaphoids on sagittal computed tomography images from healthy individuals. We analysed 62 normal scaphoids and found the mean height-length ratio, lateral intrascaphoid angle and dorsal cortical angle to be 0.58, 27° and 128°, respectively. These measurements had good-to-excellent, poor-to-moderate and moderate-to-good inter- and intra-rater reliabilities, respectively. This study provides information on normal parameters of the scaphoid that may inform clinical decision making when assessing malunion. We suggest that the lateral intrascaphoid angle should be used with great caution as a measure of deformity.Level of evidence: III.

Scaphoid non-union with pre-existing screws treated by 3D preoperative planning

Scaphoid fractures, if deemed operative, can often be treated successfully by headless compression screw fixation. Unfortunately, some patients go on to develop a scaphoid fracture non-union with screw loosening, bone resorption, bone deformity and carpal malalignment. To assist surgeons in managing these difficult cases, specifically designed scaphoid fracture plates have recently been introduced. We present a case of a scaphoid fracture non-union with retained screws and bone loss that was effectively treated by volar plate fixation using a three-dimensional (3D) printed model to assist with restoration of scaphoid morphology and implant positioning. Before surgery, 3D preoperative planning using a surface registration technique and a 3D printer was performed. Referring to the 3D-printed reduced model facilitated the prediction of gaps after reduction and helped decide the implant position and screw directions. Carpal alignment parameters gradually improved by 1 year postoperatively.

[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.

The Natural History of Scaphoid Fracture Malunion: A Scoping Review

Background  A scaphoid malunion occurs when a scaphoid fracture heals in a nonanatomic position or when the fracture is fixed without correction of the sagittal angular deformity. Although altered carpal mechanics and early osteoarthritis have been suggested as natural sequelae, the natural history and clinical outcomes are debatable. Purposes  The purpose of this study is to review and summarize the available literature regarding clinical, functional, and radiographic outcomes of patients with scaphoid malunion. Methods  A systematic search of the MEDLINE/PubMed, EMBASE, Cochrane Library, and Web of Science was performed to identify published studies concerning the clinical and radiological results of scaphoid malunion following either acute scaphoid fracture or surgically treated nonunions. Results  Five publications with a total of 83 malunions were included in the final synthesis. The diagnosis of malunion was based on computed tomography by calculating the lateral intrascaphoid angle (threshold of 35 or 45 degrees) or height/length ratio (threshold of 0.6). Self-reported and clinical evaluation techniques varied between the studies and direct comparison was not possible between the different outcome measures. Most patients demonstrated arthritic changes; however, correlation with pain and functional results was not always present. Conclusions  This scoping review confirmed that patients with malunited scaphoids seem to have higher likelihood of post traumatic arthritis. However, clinical implications remain uncertain and better methods for assessing and defining scaphoid deformity are required.

Multiplanar reformation computed tomography for carpal malalignment

Correct interpretation of scaphoid axial length and carpal malalignment is difficult owing to the complex geometry of the scaphoid. Traditional measurements, such as the scapholunate angle and radiolunate angle, have shown limited reproducibility. To improve the assessment of these measurements, we used multiplanar reformation computed tomography with added average intensity projection. Four measurements for scaphoid morphology and carpal alignment were independently measured by four observers on computed tomography scans of 39 consecutive patients who were treated conservatively for scaphoid fracture. Fleiss's kappa for categorical results showed substantial agreement for the measurements of the scapholunate and radiolunate angles. Intraclass correlation coefficients were significant for measurements of the axial length, scapholunate angle and radiolunate angle. Our results suggest that multiplanar reformation computed tomography with added average intensity projection is a reliable technique for assessment of scaphoid morphology and carpal alignment. Level of evidence: II.

The Management of the Healed Scaphoid Malunion: What to Do?

Successful bone union is only a portion of scaphoid fracture management. Malunion is possible and can alter wrist kinematics, potentially causing wrist pain and accelerated degeneration. Evaluation of scaphoid malunion begins with adequate imaging and understanding of deformity. Treatment includes nonoperative management, reconstruction, or salvage options. Correction of malunion can be obtained with an osteotomy and the use of structural graft to recreate anatomy and restore normal carpal motion. Clinical improvement of symptomatic scaphoid malunion can be reliably obtained with reconstruction, although the natural history and role for intervention in asymptomatic malunions remains unclear.

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.

Dorsal intercalated segmental instability associated with malunion of a reconstructed scaphoid

We analysed scaphoid deformity as a result of surgical treatment of scaphoid fracture nonunion and assessed the deformity associated with a dorsal intercalated segmental instability pattern of carpal malalignment. A total of 45 patients who were treated for scaphoid fracture nonunion were included in the study. The height-to-length ratio of the scaphoid was measured on computed tomographic images and used to assess scaphoid deformity. Carpal malalignment was quantified based on the radio-lunate angle. A correlation analysis between the height-to-length ratio and the radio-lunate angle was performed. Dorsal intercalated segmental instability was defined as a radio-lunate angle >15°, and a receiver operating curve analysis was used to calculate the cutoff height-to-length ratio that can be accompanied with dorsal intercalated segmental instability. Extension of the lunate increases in proportion to the flexion deformity of the scaphoid; dorsal intercalated segmental instability can occur if the height-to-length ratio of the scaphoid is >0.73.

LEVEL OF EVIDENCE

IV.

Long-Term Outcomes of Scaphoid Malunion

Background: The optimal treatment of patients with a scaphoid malunion remains controversial. The long-term outcomes of operative and nonoperative management have not been established. Methods: We conducted a retrospective review of the outcomes of all scaphoid malunions treated at single institution over a 30-year period. This included patients who underwent corrective osteotomy, salvage procedures (ie, dorsal cheilectomy, radial styloidectomy, and scaphoidectomy with midcarpal fusion), and those who refused operative intervention. The Mayo Wrist Score was determined at the time of surgical evaluation. Patient-Rated Wrist Evaluation (PRWE) and Disabilities of the Arm, Shoulder and Hand (QuickDASH) surveys were sent to all patients for long-term follow-up. Results: Seventeen patients had follow-up at a mean 21.4 years (range, 12-30 years). The mean initial lateral intrascaphoid angle was 58°. Of the 17 patients, 11 proceeded with surgery and 6 opted for nonoperative management. A corrective osteotomy was performed in 4 patients. Of the remaining 7 surgical patients, 5 patients underwent procedures such as cheilectomy and radial styloidectomy, whereas 2 patients had a scaphoidectomy with midcarpal fusion. The final mean PRWE and QuickDASH scores for corrective osteotomy, salvage procedures, and nonoperative treatment were 23 and 6, 18 and 10, and 33 and 22, respectively. Conclusion: Long-term outcomes were similar between operative and nonoperative management.

Analysis of deformity in scaphoid non-unions using two- and three-dimensional imaging

Pre-operative assessment of the deformity in scaphoid non-unions influences surgical decision-making. To characterize deformity, we used three-dimensional computed tomographic modelling in 28 scaphoid non-unions, and quantified bone loss, dorsal osteophyte volume and flexion deformity. We further related these three-dimensional parameters to the intrascaphoid and capitate-lunate angles, and stage of scaphoid non-union advanced collapse assessed on conventional two-dimensional images and to the chosen surgical procedure. Three-dimensional flexion deformity (mean 26°) did not correlate with intrascaphoid and capitate-lunate angles. Osteophyte volume was positively correlated with bone loss and stage of scaphoid non-union advanced collapse. Osteophyte volume and bone loss increased over time. Three-dimensional modelling enables the quantification of bone loss and osteophyte volume, which may be valuable parameters in the characterization of deformity and subsequent decision-making about treatment, when taken in addition to the clinical aspects and level of osteoarthritis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Level IV.

Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT) protocol: a pragmatic multi-centre randomised controlled trial of cast treatment versus surgical fixation for the treatment of bi-cortical, minimally displaced fractures of the scaphoid waist in adults

Background

A scaphoid fracture is the most common type of carpal fracture affecting young active people. The optimal management of this fracture is uncertain. When treated with a cast, 88 to 90 % of these fractures unite; however, for the remaining 10-12 % the non-union almost invariably leads to arthritis. The alternative is surgery to fix the scaphoid with a screw at the outset.

Methods/Design

We will conduct a randomised controlled trial (RCT) of 438 adult patients with a “clear” and “bicortical” scaphoid waist fracture on plain radiographs to evaluate the clinical effectiveness and cost-effectiveness of plaster cast treatment (with fixation of those that fail to unite) versus early surgical fixation. The plaster cast treatment will be immobilisation in a below elbow cast for 6 to 10 weeks followed by mobilisation. If non-union is confirmed on plain radiographs and/or Computerised Tomogram at 6 to 12 weeks, then urgent surgical fixation will be performed. This is being compared with immediate surgical fixation with surgeons using their preferred technique and implant. These treatments will be undertaken in trauma units across the United Kingdom. The primary outcome and end-point will be the Patient Rated Wrist Evaluation (a patient self-reported assessment of wrist pain and function) at 52 weeks and also measured at 6, 12, 26 weeks and 5 years. Secondary outcomes include an assessment of radiological union of the fracture; quality of life; recovery of wrist range and strength; and complications. We will also qualitatively investigate patient experiences of their treatment.

Discussion

Scaphoid fractures are an important public health problem as they predominantly affect young active individuals in the more productive working years of their lives. Non-union, if untreated, can lead to arthritis which can disable patients at a very young age. There is a rapidly increasing trend for immediate surgical fixation of these fractures but there is insufficient evidence from existing RCTs to support this. The SWIFFT Trial is a rigorously designed and adequately powered study which aims to contribute to the evidence-base to inform clinical decisions for the treatment of this common fracture in adults.

Trial registration

The trial is registered with the International Standard Randomised Controlled Trial Register (ISRCTN67901257). Date registration assigned was 13/02/2013.

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.

Three-Dimensional Assessment of Bilateral Symmetry of the Scaphoid: An Anatomic Study

Preoperative 3D CT imaging techniques provide displacement analysis of the distal scaphoid fragment in 3D space, using the matched opposite scaphoid as reference. Its accuracy depends on the presence of anatomical bilateral symmetry, which has not been investigated yet using similar techniques. Our purpose was to investigate symmetry by comparing the relative positions of distal and proximal poles between sides. We used bilateral CT scans of 19 adult healthy volunteers to obtain 3D scaphoid models. Left proximal and distal poles were matched to corresponding mirrored right sides. The left-to-right positional differences between poles were quantified in terms of three translational and three rotational parameters. The mean (SD) of ulnar, dorsal, and distal translational differences of distal poles relative to proximal poles was 0.1 (0.6); 0.4 (1.2); 0.2 (0.6) mm and that of palmar rotation, ulnar deviation, and pronation differences was −1.1 (4.9); −1.5 (3.3); 1.0 (3.7)°, respectively. These differences did not significantly differ from zero and thus were not biased to left or right side. We proved that, on average, the articular surfaces of scaphoid poles were symmetrically aligned in 3D space. This suggests that the contralateral scaphoid can serve as reference in corrective surgery. No level of evidence is available.

Clinical outcome of scaphoid malunion as a result of scaphoid fracture nonunion surgical treatment: A 5-year minimum follow-up study

BACKGROUND

Although malunion resulting from reconstruction for scaphoid fracture nonunion is a typical complication, there has been little consideration regarding its clinical outcomes.

HYPOTHESIS

The quality of restoration of the scaphoid anatomy may have little effect on clinical outcomes.

MATERIALS AND METHODS

Twenty-five patients with scaphoid fracture nonunion underwent curettage and internal fixation with bone grafting performed by a single surgeon, and they were followed up for a minimum of 5 years. Some of these patients comprised the malunion group if the height/length ratio (H/L ratio) in the most central longitudinal computed tomographic image was more than 0.6. We compared the clinical outcomes of the malunion group with a well-union group based on various clinical scores (Patient Evaluation Measure, Disabilities of the Arm, Shoulder and Hand, modified Mayo wrist scoring system).

RESULTS

The average follow-up period was 81 months (range: 65-110), and 15 cases among the 25 patients were included in the malunion group. There were no statistical differences in the clinical scores between malunions (15 cases) and well unions (10 cases), and there was no correlation between the H/L ratios and the clinical outcomes.

CONCLUSION

The clinical outcomes of malunited scaphoids after reconstruction for scaphoid fractures nonunion did not differ significantly from well-united scaphoids at a minimum 5-year follow-up.

3-dimensional analysis of scaphoid fracture angle morphology

PURPOSE

Scaphoid fractures are classified according to their 2-dimensional radiographic appearance, and transverse waist fractures are considered the most common. Our hypothesis was that most scaphoid fractures are not perpendicular to the longitudinal axis of the scaphoid (ie, not transverse).

METHODS

Computerized 3-dimensional analyses were performed on 124 computed tomography scans of acute scaphoid fractures. Thirty of the fractures were displaced and virtually reduced. The angle between the scaphoid's first principal axis (longitudinal axis) and the fracture plane was analyzed for location and displacement. The distal radius articular surface was used to depict the volar-dorsal vector of the wrist.

RESULTS

There were 86 fractures of the waist, 13 of the distal third, and 25 of the proximal third. The average angle between the scaphoid longitudinal axis and the fracture plane was 53° for all fractures and 56° for waist fractures, both differing significantly from a 90°, transverse fracture. The majority of fracture planes were found to have a volar distal to dorsal proximal (horizontal oblique) inclination relative to the volar-dorsal vector.

CONCLUSIONS

Most waist fractures were horizontal oblique and not transverse. According to these findings, fixation of all fractures along the longitudinal axis of the scaphoid may not be the optimal mode of fixation for most. A different approach may be needed in accordance with the fracture plane.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Quantifying scaphoid malalignment based upon height-to-length ratios obtained by 3-dimensional computed tomography

PURPOSE

To determine if 3-dimensional height-to-length (H/L) measurements including coronal plane assessment will improve malalignment detection of scaphoid fractures and to determine if more waist than proximal pole nonunions are malaligned.

METHODS

Computed tomography scans of uninjured wrists (n = 74) were used to obtain 3-dimensional models of healthy scaphoids. These models were used to determine 95% normal ranges of the H/L ratio in standard sagittal and coronal planes in an automated fashion. Subsequently, the H/L ratios of fibrous nonunions (n = 26) were compared with these normal ranges and were classified as either aligned or malaligned.

RESULTS

The mean normal H/L ratio in the sagittal plane was 0.61 (range, 0.54-0.69) and in the coronal plane 0.42 (range, 0.36-0.48). The mean H/L ratios of the nonunions differed from those of the healthy scaphoids in these planes: 0.65 and 0.48, respectively. Based on sagittal plane evaluation of all nonunions, 46% exceeded the normal H/L range versus 54% based on combining sagittal and coronal plane measurements. More waist nonunions (71%) than proximal pole nonunions (22%) exceed the normal H/L range.

CONCLUSIONS

Evaluation of the H/L ratio in the coronal plane provided valuable additional information for the detection of scaphoid deformities. More malaligned cases were found for waist nonunions than for proximal pole nonunions.

CLINICAL RELEVANCE

This method may be a helpful diagnostic tool to detect malalignment and to choose between in situ fixation or reconstruction.

Reliability and validity of carpal alignment measurements in evaluating deformities of scaphoid fractures

PURPOSE

Several radiographic carpal alignment indices are used to evaluate the deformities of scaphoid fractures. The purpose of this study was to determine the reliabilities and validities of radiographic carpal alignment indices commonly used to evaluate deformities of scaphoid fractures.

METHODS

Thirty-six patients with a scaphoid fracture were evaluated. Five carpal alignment indices were assessed on lateral plain radiographs, namely, scapholunate angle, radioscaphoid angle, radiolunate angle, radiocapitate angle, and capitolunate angle. Three examiners measured these radiographic indices at two sessions, and intraobserver and interobserver reliabilities were determined and expressed as intraclass correlation coefficients. Discriminant validities of radiographic carpal alignment indicies between injured and uninjured wrists were evaluated. For convergent validity testing, the correlation between the radiographic carpal alignment indices and intrascaphoid angles (ISAs) or height-to-length (HL) ratios on CT longitudinal scans was assessed. Further, carpal alignment indices after surgical reconstruction were compared to the Mayo wrist score.

RESULTS

Scapholunate and radiolunate angles had the highest reliabilities, and radiocapitate angle had the lowest. Radiolunate angle had the highest discriminant validity followed by scapholunate, and capitolunate angles. In convergent validity testing, scapholunate angles and radiolunate angles correlated with ISA angles, and radiolunate and capitolunate angles correlated with HL ratios. Only the radiolunate angles correlated with the Mayo wrist scores.

CONCLUSIONS

Among radiographic carpal alignment measures, radiolunate angle is the most reliable and valid carpal alignment index for evaluating deformities of scaphoid fractures. Scapholunate and capitolunate angles could be used as an alternative, but have less validity.

Positioning evaluation of corrective osteotomy for the malunited radius: 3-D CT versus 2-D radiographs

The authors retrospectively investigated the postoperative position of the distal radius after a corrective osteotomy using 2-dimensional (2-D) and 3-dimensional (3-D) imaging techniques to determine whether malposition correlates with clinical outcome. Twenty-five patients who underwent a corrective osteotomy were available for follow-up. The residual positioning errors of the distal end were determined retrospectively using standard 2-D radiographs and 3-D computed tomography evaluations based on a scan of both forearms, with the contralateral healthy radius serving as reference. For 3-D analysis, use of an anatomical coordinate system for each reference bone allowed the authors to express the residual malalignment parameters in displacements (Δx, Δy, Δz) and rotations (Δφx, Δφy, Δφz) for aligning the affected bone in a standardized way with the corresponding reference bone. The authors investigated possible correlations between malalignment parameters and clinical outcome using patients' questionnaires. Two-dimensional radiographic evaluation showed a radial inclination of 24.9°±6.8°, a palmar tilt of 4.5°±8.6°, and an ulnar variance of 0.8±1.7 mm. With 3-D analysis, residual displacements were 2.6±3 (Δx), 2.4±3 (Δy), and -2.2±4 (Δz) mm. Residual rotations were -6.2°±10° (Δφx), 0.3°±7° (Δφy), and -5.1°±10° (Δφz). The large standard deviation is indicative of persistent malalignment in individual cases. Statistically significant correlations were found between 3-D rotational deficits and clinical outcome but not between 2-D evaluation parameters. Considerable residual malalignments and statistically significant correlations between malalignment parameters and clinical outcome confirm the need for better positioning techniques.

Training improves interobserver reliability for the diagnosis of scaphoid fracture displacement

BACKGROUND

The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability.

QUESTIONS/PURPOSES

We tested whether training can improve interobserver reliability and sensitivity, specificity, and accuracy for the diagnosis of scaphoid fracture displacement on radiographs and CT scans.

METHODS

Sixty-four orthopaedic surgeons rated a set of radiographs and CT scans of 10 displaced and 10 nondisplaced scaphoid fractures for the presence of displacement, using a web-based rating application. Before rating, observers were randomized to a training group (34 observers) and a nontraining group (30 observers). The training group received an online training module before the rating session, and the nontraining group did not. Interobserver reliability for training and nontraining was assessed by Siegel's multirater kappa and the Z-test was used to test for significance.

RESULTS

There was a small, but significant difference in the interobserver reliability for displacement ratings in favor of the training group compared with the nontraining group. Ratings of radiographs and CT scans combined resulted in moderate agreement for both groups. The average sensitivity, specificity, and accuracy of diagnosing displacement of scaphoid fractures were, respectively, 83%, 85%, and 84% for the nontraining group and 87%, 86%, and 87% for the training group. Assuming a 5% prevalence of fracture displacement, the positive predictive value was 0.23 in the nontraining group and 0.25 in the training group. The negative predictive value was 0.99 in both groups.

CONCLUSIONS

Our results suggest training can improve interobserver reliability and sensitivity, specificity and accuracy for the diagnosis of scaphoid fracture displacement, but the improvements are slight. These findings are encouraging for future research regarding interobserver variation and how to reduce it further.

Management of displaced fractures of the waist of the scaphoid: meta-analyses of comparative studies

INTRODUCTION

Scaphoid fractures with displacement have a higher incidence of nonunion that can cause pain and reduced movement, strength and function. The aim of this study was to review the evidence available and establish the risk of nonunion associated with management of displaced fractures of the waist of the scaphoid.

METHODS

Electronic databases were searched using the Medical Subject Headings (MeSH) controlled vocabulary (scaphoid fractures, AND'd with displaced, or nonunion, or non-healing or cast immobilisation, or plaster or surgery). At present, there are no randomised, controlled trials or studies comparing fixation to plaster cast treatment of displaced fractures of the scaphoid. The search was therefore limited to observational studies of displaced fractures of the scaphoid treated in a plaster cast (non-operative group) or fixed surgically (operative group). The criterion for displacement was limited to gap or step of more than 1 mm. In the non-operative group, we compared the outcome of displaced and undisplaced fractures of the waist of the scaphoid treated in a plaster cast. In the operative group, contingency table analysis was used to calculate the odds ratio of nonunion with plaster treatment compared to surgery.

RESULTS

In the non-operative group, seven studies were included in a meta-analysis with a total of 1401 scaphoids. Ninety-three percent (1311 scaphoids) of these scaphoid fractures healed in a plaster cast. A total of 207 (15%) of all scaphoid fractures showed displacement of at least 1 mm (gap/step) between fracture fragments. Nonunion was identified in 18% (37/207) of displaced scaphoid fractures treated in a plaster cast. The pooled relative risk of fracture nonunion was 4.4 (95% confidence interval (CI): 2.3-8.7; p=0.00; I(2)=54.3%). In the surgical group, we identified six observational studies in which 157 'displaced' fractures of the scaphoid were surgically fixed. Only two of these fractures did not heal. The odds of nonunion were 17 times higher with plaster cast treatment than surgery.

CONCLUSIONS

Displaced fractures of scaphoid have a four times higher risk of nonunion than undisplaced fractures when treated in a plaster cast, and the patients should be advised of this risk. Nonunion is more likely if a displaced fracture of the scaphoid is treated in a plaster cast.

Three-dimensional assessment of bilateral symmetry of the radius and ulna for planning corrective surgeries

PURPOSE

The contralateral unaffected side is often used as a reference in planning a corrective osteotomy of a malunited distal radius. Two-dimensional radiographs have proven unreliable in assessing bilateral symmetry, so we assessed 3-dimensional configurations to assess bilateral symmetry.

METHODS

We investigated bilateral symmetry using 3-dimensional imaging techniques. A total of 20 healthy volunteers without previous wrist injury underwent a volumetric computed tomography of both forearms. The left radius and ulna were segmented to create virtual 3-dimensional models of these bones. We selected a distal part and a larger proximal part from these bones and matched them with a mirrored computed tomographic image of the contralateral side. This allowed us to calculate the relative displacements (Δx, Δy, Δz) and rotations (Δφx, Δφy, Δφz) for aligning the left bone with the right bone segments. We investigated the relation between longitudinal length differences in radiuses and ulnas.

RESULTS

Relative differences of the radiuses were (Δx, Δy, Δz): -0.81 ± 1.22 mm, -0.01 ± 0.64 mm, and 2.63 ± 2.03 mm; and (Δφx, Δφy, Δφz): 0.13° ± 1.00°, -0.60° ± 1.35°, and 0.53° ± 5.00°. The same parameters for the ulna were (Δx, Δy, Δz): -0.22 ± 0.82 mm, 0.52 ± 0.99 mm, 2.08 ± 2.33 mm; and (Δφx, Δφy, Δφz): -0.56° ± 0.96°, -0.71° ± 1.51°, and -2.61° ± 5.58°. There is a strong relation between absolute length differences (Δz) between the radiuses and ulnas of individuals.

CONCLUSIONS

We observed substantial length and rotational differences around the longitudinal bone axis in healthy individuals. Surgical planning using the unaffected side as a reference may not be as useful as previously assumed. However, including the length difference of the adjacent forearm bones can be useful in improving length correction in computer-assisted planning of radius or ulna osteotomies and in other reconstructive surgery procedures.

CLINICAL RELEVANCE

Bilateral symmetry is important in reconstructive surgery procedures where the contralateral unaffected side is often used as a reference for planning and evaluation.

Scaphoid morphology and clinical outcomes in scaphoid reconstructions

Scaphoid malunion and carpal malalignment can result after scaphoid reconstruction, if the two fragments are not properly reduced before fixation. However, currently there is no information about which degree of deformity or malalignment can be tolerated without impairing clinical function. The purpose of this study was to investigate the influence of the scaphoid morphology and carpal alignment on clinical outcomes after scaphoid reconstruction. A total of 65 patients with an average age of 29 years were followed-up after a mean period of 45 months. In all patients, osseous union after a first-time scaphoid reconstruction in the middle third had been confirmed. Scapholunate (SL) and radiolunate (RL) angles were obtained on plain radiographs as were intrascaphoid (ISA) and dorsal cortical (DCA) angles and the height/length (H/L) ratio of the reconstructed scaphoid on computed tomography (CT) scans. These parameters were correlated with clinical outcome measures. RL angles correlated significantly with wrist range of motion, grip strength and pain levels, whilst SL angles, ISA, DCA and H/L ratio failed to show significant correlations. Our data suggest that clinical outcome is correlated with correct restoration of bone morphology and carpal alignment. After reconstruction, the RL angle should not exceed 10°.

Displaced fracture of the waist of the scaphoid

A displaced fracture of the scaphoid is one in which the fragments have moved from their anatomical position or there is movement between them when stressed by physiological loads. Displacement is seen in about 20% of fractures of the waist of the scaphoid, as shown by translation, a gap, angulation or rotation. A CT scan in the true longitudinal axis of the scaphoid demonstrates the shape of the bone and displacement of the fracture more accurately than do plain radiographs. Displaced fractures can be treated in a plaster cast, accepting the risk of malunion and nonunion. Surgically the displacement can be reduced, checked radiologically, arthroscopically or visually, and stabilised with headless screws or wires. However, rates of union and deformity are unknown. Mild malunion is well tolerated, but the long-term outcome of a displaced fracture that healed in malalignment has not been established.

This paper summarises aspects of the assessment, treatment and outcome of displaced fractures of the waist of the scaphoid.

The length and position of the long axis of the scaphoid measured by analysis of three-dimensional reconstructions of computed tomography images

We established the maximum length and the position of the long axis of the scaphoid from three-dimensional reconstructions of spiral computed tomography in 30 pairs of wrists. The distance between two points on the three-dimensional scaphoid surface model were calculated using commercially available software and corresponding coordinates of the two points were documented. The mean length was 29.3 (SD 1.6) mm for men and 26.6 (SD 1.8) mm for women. The location of the distal point was at the centre of the scaphoid tuberosity, with the proximal point of the long axis located at the dorsal ridge of the scapholunate facet.

The clinical outcome of scaphoid fracture malunion at 1 year

The aim of this study was to assess the effect of malunion of scaphoid fractures on the clinical outcome at 1 year. Forty-two consecutive patients with united scaphoid waist fractures which had been treated non-operatively underwent longitudinal CT scans to confirm union and assess malunion at 12 to 18 weeks after injury. A blind clinical assessment was made and the Patient Evaluation Measure (PEM) and DASH questionnaires were completed by all the patients 1 year after injury. The group consisted of 38 men and four women with a mean age of 31 years at the time of injury. Correlation analysis revealed no significant relationships between any of the outcome measures (range of motion, grip strength and PEM and DASH scores) and any of the three measures of malunion (height-to-length ratio, the dorsal cortical angle and the lateral intra-scaphoid angle).