Determining diagnosis of scaphoid healing: Comparison of cone beam CT and X-ray after six weeks of immobilization

The diagnostic characteristics and reliability of radiological methods used in the assessment of scaphoid fracture union : a systematic review

Aims

To evaluate the diagnostic characteristics and reliability of radiological methods used to assess scaphoid fracture union through a systematic review and meta-analysis.

Methods

MEDLINE, Embase, and the Cochrane Library were searched from inception to June 2022. Any study reporting data on the diagnostic characteristics and/or the reliability of radiological methods assessing scaphoid union was included. Data were extracted and checked for accuracy and completeness by pairs of reviewers. Methodological quality was assessed using the QUADAS-2 tool.

Results

A total of 13 studies were included, which were three assessed radiographs alone, six CT alone, and four radiographs + CT. Diagnostic sensitivity was assessed by CT in three studies (0.78, 0.78, and 0.73) and by radiographs in two studies (0.65, 0.75). Diagnostic specificity was assessed by CT in three studies (0.96, 0.8, 0.4) and by radiographs in two studies (0.67, 0.4). Interobserver reliability was assessed for radiographs by seven studies (two fair, four moderate, and one substantial) and for CT in nine studies (one fair, one moderate, six substantial, and one almost perfect).

Conclusion

There is evidence to support both the use of CT and radiographs in assessing scaphoid fracture union. Although CT appears superior in terms of both its diagnostic characteristics and reliability, further research is necessary to better define the optimal clinical pathways for patients.

Inter- and Intraobserver Reliability for the Computed Tomography Scan Assessment of Union After Surgery for Scaphoid Fractures and Nonunion

Purpose

Assessment of scaphoid union after operative treatment might be associated with uncertainty, disagreement, and misinterpretation. Union is defined as consolidation on three of four X-ray views. Computed tomography (CT) scans are increasingly used to evaluate union of scaphoid fractures and nonunion. It allows multiplanar assessment of the scaphoid. Reliability in CT scan assessment of union after operative intervention is limited. We hypothesized that inter- and intraobserver reliability of the CT scan assessment of union after operative treatment for scaphoid fracture and nonunion are substantial and better in fracture cases.

Methods

An institutional search identified 230 patients with operative intervention. According to the sample size, we randomly selected 60 patients (30 fractures and 30 nonunion), with age above 18 years and CT scans 6-26 weeks after surgery, when uncertainty about healing status is most pronounced. Three observers evaluated the CT scans on two occasions 6 weeks apart. Observers classified the scaphoid into two categories: No/partial/full union and >/<50% union.

Results

Interrater agreement in no/partial/full union was overall substantial, substantial in fractures, and moderate for nonunion cases. Interobserver agreement for >/<50% union was overall moderate and moderate for both fractures and nonunion groups. The interrater agreement of no/partial/full union with CT scans ≥12 weeks after surgery was substantial versus fair for the cases below. Intrarater agreement was overall better in cases with CT scans ≥12 weeks postoperative versus earlier.

Conclusions

CT scans show substantial agreement in the assessment of no/partial/full union after operative intervention, although the presence of metal artifacts and bone grafts potentially impair visibility among observers. The agreement was better in scaphoid fractures. CT scan assessment of >/<50% union is with overall moderate agreement. Inter- and intrarater agreement is improved when CT scans are taken 12 weeks or later after operative treatment, blinded to the clinical information.

Level of Evidence

Diagnostic, III.

The Role of Botulinum Neurotoxin A in the Conservative Treatment of Fractures: An Experimental Study on Rats

This paper explores the role of botulinum neurotoxin in aiding fracture recovery through temporary muscle paralysis. Specifically, it investigates the effects of botulinum neurotoxin-induced paralysis of the sternocleidomastoid muscle on clavicle fractures in rats. The research aims to assess safety, effectiveness, and the impact on fracture healing. Healthy male Albino Wistar rats were divided into four groups: clavicle fracture, botulinum neurotoxin injection, both, and control. Surgeries were conducted under anaesthesia, and postoperatively, animals were monitored for 28 days. Euthanasia and radiological assessment followed, examining fracture healing and muscle changes, while tissues were histopathologically evaluated. The modified Lane-Sandhu scoring system was used for the radiographic evaluation of clavicle fractures, and the results varied from complete healing to nonunion. Histopathological examination at 28 days postfracture showed fibrous tissue, mesenchymal cells, and primary callus formation in all groups. Despite varied callus compositions, botulinum neurotoxin administration did not affect clavicle healing, as evidenced by similar scores to the control group. Several studies have explored botulinum neurotoxin applications in fracture recovery. Research suggests its potential to enhance functional recovery in certain types of fractures. Theoretical benefits include managing muscle spasticity, aiding reduction techniques, and preventing nonunion. However, botulinum neurotoxin's transient effect and nonuniversal applications should be considered. The present study found that botulinum toxin had no clear superiority in healing compared to controls, while histological evaluation showed potential adverse effects on muscle tissue. Further research is essential to understand its risk-benefit balance and long-term effects.

Arthroscopic versus open cancellous bone grafting for scaphoid delayed/nonunion in adults (SCOPE-OUT): study protocol for a randomized clinical trial

BACKGROUND

Scaphoid non-union results in pain and decreased hand function. Untreated, almost all cases develop degenerative changes. Despite advances in surgical techniques, the treatment is challenging and often results in a long period with a supportive bandage until the union is established. Open, corticocancellous (CC) or cancellous (C) graft reconstruction and internal fixation are often preferred. Arthroscopic assisted reconstruction with C chips and internal fixation provides minimal trauma to the ligament structures, joint capsule, and extrinsic vascularization with similar union rates. Correction of deformity after operative treatment is debated with some studies favouring CC, and others found no difference. No studies have compared time to union and functional outcomes in arthroscopic vs. open C graft reconstruction. We hypothesize that arthroscopic assisted C chips graft reconstruction of scaphoid delayed/non-union provides faster time to union, by at least a mean 3 weeks difference.

METHODS

Single site, prospective, observer-blinded randomized controlled trial. Eighty-eight patients aged 18-68 years with scaphoid delayed/non-union will be randomized, 1:1, to either open iliac crest C graft reconstruction or arthroscopic assisted distal radius C chips graft reconstruction. Patients are stratified for smoking habits, proximal pole involvement and displacement of > / < 2 mm. The primary outcome is time to union, measured with repeated CT scans at 2-week intervals from 6 to 16 weeks postoperatively. Secondary outcomes are Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH), visual analogue scale (VAS), donor site morbidity, union rate, restoration of scaphoid deformity, range of motion, key-pinch, grip strength, EQ5D-5L, patient satisfaction, complications and revision surgery.

DISCUSSION

The results of this study will contribute to the treatment algorithm of scaphoid delayed/non-union and assist hand surgeons and patients in making treatment decisions. Eventually, improving time to union will benefit patients in earlier return to normal daily activity and reduce society costs by shortening sick leave.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05574582. Date first registered: September 30, 2022. Items from the WHO trial registry are found within the protocol.

Radiation exposure to fetus from extremity CBCT examinations

PURPOSE

To evaluate fetal doses from extremity CBCT examinations at different stages of pregnancy and to investigate different methods of fetal dose optimization.

METHOD

Fetal doses were measured in an anthropomorphic phantom for two CBCT examination protocols - knee and elbow. The measurements were made at three different heights representing the three trimesters during pregnancy and three different depths in the phantom. The effect of soft tissue layer, tube voltage, add-on device shield and body angulation on fetal dose were investigated.

RESULTS

The fetal doses in clinical examination protocols were in the range of 3.4 to 6.0 µGy during knee examinations and 2.9 to 7.7 µGy during elbow examinations depending on the depth of the fetus and the stage of pregnancy. A soft tissue layer representing variative body composition above abdomen region decreased the fetal dose up to 19 % in knee and up to 21 % in elbow examinations. Using lower tube voltage decreased the fetal doses up to 45 % (knee) and 51 % (elbow). An add-on device shield decreased the fetal doses up to 91 % (knee) and up to 75 % (elbow). Turning the body away from the device bore reduced the fetal doses up to 62 %. The conversion factor to convert an entrance surface dose to the fetal dose ranged from 0.4 to 0.6.

CONCLUSIONS

The fetal doses from CBCT examinations of extremities are low and do not produce a concern about radiation detriment to the fetus. The most efficient way found to reduce the fetal dose was to use the add-on device shielding.

Comparison of scattered entrance skin dose burden in MSCT, CBCT, and X-ray for suspected scaphoid injury: Regional dose measurements in a phantom model

INTRODUCTION

Scaphoid radiography has poor sensitivity for acute fracture detection and often requires repeat delayed imaging. Although magnetic resonance (MR) imaging is considered the gold standard, computed tomography (CT) is often used as an alternative due to ease of access. Cone-Beam CT (CBCT) offers equivalent diagnostic efficacy to Multi Slice CT (MSCT) at reduced dose. We aimed to establish the difference in scattered dose between modalities for scaphoid imaging.

METHODS

Anatomical regional entrance surface dose measurements were taken at 3 regions on an anthropomorphic torso phantom positioned as a patient to a wrist phantom undergoing scaphoid imaging for three modalities (CBCT, MSCT, four-view projection radiography). Exposure factors were based on audit of clinical exposures. Each dose measurement was repeated three times per anatomical region, modality, exposure setting and projection.

RESULTS

Under unpaired T-test CBCT gave significantly lower mean dose at the neck (1.64 vs 18 mGy), chest (2.78 vs 8.01) and abdomen (1.288 vs 2.93) than MSCT (p < .0001). However CBCT had significantly higher mean dose than four-view radiography at the neck, chest and abdomen (0.031, 0.035, and 0.021 mGy) (p < .0001).

CONCLUSION

CBCT of the wrist carries a significantly higher scattered radiation dose to the neck, chest and abdomen than four view scaphoid radiography, but significantly lower scattered dose than MSCT of the wrist of equivalent diagnostic value.

IMPLICATIONS FOR PRACTICE

The use of CBCT for scaphoid injury carries significantly lower scattered dose to radio-sensitive structures investigated here than equivalent MSCT, and may be of greater use as an early cross-sectional investigation for suspected scaphoid fracture.

The effect of tin prefiltration on extremity cone-beam CT imaging with a twin robotic X-ray system

INTRODUCTION

While tin prefiltration is established in various CT applications, its value in extremity cone-beam CT relative to optimized spectra has not been thoroughly assessed thus far. This study aims to investigate the effect of tin filters in extremity cone-beam CT with a twin-robotic X-ray system.

METHODS

Wrist, elbow and ankle joints of two cadaveric specimens were examined in a laboratory setup with different combinations of prefiltration (copper, tin), tube voltage and current-time product. Image quality was assessed subjectively by five radiologists with Fleiss' kappa being computed to measure interrater agreement. To provide a semiquantitative criterion for image quality, contrast-to-noise ratios (CNR) were compared for standardized regions of interest. Volume CT dose indices were calculated for a 16 cm polymethylmethacrylate phantom.

RESULTS

Radiation dose ranged from 17.4 mGy in the clinical standard protocol without tin filter to as low as 0.7 mGy with tin prefiltration. Image quality ratings and CNR for tin-filtered scans with 100 kV were lower than for 80 kV studies with copper prefiltration despite higher dose (11.2 and 5.6 vs. 4.5 mGy; p < 0.001). No difference was ascertained between 100 kV scans with tin filtration and 60 kV copper-filtered scans with 75% dose reduction (subjective: p = 0.101; CNR: p = 0.706). Fleiss' kappa of 0.597 (95% confidence interval 0.567-0.626; p < 0.001) indicated moderate interrater agreement.

CONCLUSION

Considerable dose reduction is feasible with tin prefiltration, however, the twin-robotic X-ray system's low-dose potential for extremity 3D imaging is maximized with a dedicated low-kilovolt scan protocol in situations without extensive beam-hardening artifacts.

IMPLICATIONS FOR PRACTICE

Low-kilovolt imaging with copper prefiltration provides a superior trade-off between dose reduction and image quality compared to tin-filtered cone-beam CT scan protocols with higher tube voltage.