[Trans-scapho-perilunar fracture-dislocation: a case report]. / Fractura-luxación transescafo-perilunar: reporte de un caso clínico.

Trans-scaphoid perilunate fractures-dislocations are rare injuries caused by high-energy trauma of the wrist. Diagnosis is based on medical history, physical examination, and tools such as radiographs, computed tomography scan, and magnetic resonance imaging. Early treatment consists of closed reduction and casting to stabilize the limb. Definitive treatment is surgical and includes bone and soft tissue repair. A case of trans-scaphoid perilunate fracture-dislocation is presented, along with diagnosis, management and outcome.

Las fracturas-luxaciones transescafo-perilunares son lesiones infrecuentes causadas por impactos de alta energía hacia la muñeca. El diagnóstico se basa en la historia clínica, exploración física y herramientas como la radiografía, la tomografía computarizada y la resonancia magnética. El manejo inmediato consiste en una reducción cerrada e inmovilización para estabilizar la extremidad. El tratamiento definitivo es de carácter quirúrgico e incluye la reparación ósea y de tejidos blandos. Se presenta un caso de fractura-luxación transescafo-perilunar, su diagnóstico, manejo y evolución.

Torus fractures - diagnosis and management.

Torus fractures are a common paediatric injury involving the distal radius. Patients typically present following a fall onto the outstretched hand, with wrist pain as their primary complaint. The principal investigation of choice is a plain radiograph of the wrist joint. These fractures should be managed with a soft-bandage and immediate discharge approach and do not require specialist follow-up. Clinicians have historically had differing views regarding optimal management of torus fractures. It is therefore important for hospital clinicians to uniformly understand the most up-to-date management of this condition. This review provides an overview of the epidemiology, anatomy, diagnosis and management, with an aim to improve outcomes.

Dorsal Radiocarpal Dislocation with Radial Styloid Fracture Treated with Arthroscopy-Assisted Reduction and Internal Fixation: A Report of Two Cases.

Radiocarpal dislocation is an uncommon injury that is usually caused by high-energy trauma. Herein, we present two cases of dorsal radiocarpal dislocation with radial styloid fractures that were treated by arthroscopy-assisted reduction and internal fixation. Wrist arthroscopy provides accurate information on intra-articular fractures and carpal and/or intracarpal ligamentous tears of the radiocarpal joint. Furthermore, the procedure enables simultaneous anatomical reduction of intra-articular fractures and radiocarpal and/or intercarpal ligament repair. Arthroscopy-assisted reduction and internal fixation yield satisfactory outcomes for patients presenting with dorsal radiocarpal dislocation and radial styloid fractures.

Detection of scapholunate interosseous ligament injury using dynamic computed tomography-derived arthrokinematics: A prospective clinical trial.

Scapholunate interosseous ligament injuries are a major cause of wrist instability and can be difficult to diagnose radiographically. To improve early diagnosis of scapholunate ligament injuries, we compared injury detection between bilateral routine clinical radiographs, static CT, and dynamic four-dimensional CT (4DCT) during wrist flexion-extension and radioulnar deviation. Participants with unilateral scapholunate ligament injuries were recruited to a prospective clinical trial investigating the diagnostic utility of 4DCT imaging for ligamentous wrist injury. Twenty-one participants underwent arthroscopic surgery to confirm scapholunate ligament injury. Arthrokinematics, defined as distributions of interosseous proximities across radioscaphoid and scapholunate articular surfaces at different positions within the motion cycle, were used as CT-derived biomarkers. Preoperative radiographs, static CT, and extrema of 4DCT were compared between uninjured and injured wrists using Wilcoxon signed rank or Kolmogorov-Smirnov tests. Median interosseous proximities at the scapholunate interval were significantly greater in the injured versus the uninjured wrists at static-neutral and maximum flexion, extension, radial deviation, and ulnar deviation. Mean cumulative distribution functions at the radioscaphoid joint were not significantly different between wrists but were significantly shifted at the scapholunate interval towards increased interosseous proximities in injured versus uninjured wrists in all positions. Median and cumulative distribution scapholunate proximities from static-neutral and 4DCT-derived extrema reflect injury status.

Distinct patterns of fracture propagation in distal radial fractures and the relationship to the ulnar head.

BACKGROUND: The aim was to assess the direction of distal radius fractures and their relationship to the ulnar head. METHODS: We reviewed the 160 wrist radiographs. The fracture line was measured on the postero-anterior and lateral radiographs relative to the long axis of the forearm and the relationship to the ulnar head. FINDINGS: PA radiographs: the fracture line ran distal ulnar to proximal radial (ulnar to radial) in 11%, transverse in 74% and distal radial to proximal ulnar (radial to ulnar) in 16%. Lateral radiographs: the fracture line ran distal volar to proximal dorsal in 88%, transverse in two 1% and dorsal to volar in 11%. Radial shift (7.5%) only occurred with ulnar to radial or transverse fractures. The ulnar to radial fracture line started at the proximal end of the ulnar head/distal radio-ulnar joint in 88%. The radial to ulnar fracture line started ended a mean of 2.5 mm proximal to the distal radio-ulnar joint (p < 0.01). The transverse fracture line started at the base of the distal radio-ulnar joint in 53% and proximally in 47%. INTERPRETATION: There are two distinct coronal patterns: radial to ulnar ending c. 2 mm proximal to the distal radio-ulnar joint; ulnar to radial starting at the proximal distal radio-ulnar joint. There may be third pattern - transverse fractures; these may be variants of the above. Sagittally the main direction is volar to dorsal but 11% are obverse. This is the first description of distinct fracture patterns in extra-articular distal radius fractures. In addition the fracture patterns appear to correlate with different directions of force transmission which fit with our understanding of falling and the relatively uncontrolled impact of the wrist/hand with the ground. These patterns of fracture propagation help understand how the biomechanics of wrist fractures and may enable prediction of collapse.

Chronic Volar Dislocation of the Distal Radioulnar Joint Stabilised by a Partial Extensor Carpi Ulnaris Tendon Strip - A Case Report.

Volar dislocation of the distal radioulnar joint is a rare injury that is often missed at initial presentation. We report a 21-year-old male patient who presented 2 months after sustaining this injury. He was successfully managed by open reduction and reconstruction of the dorsal radioulnar ligament using a partial distally based extensor carpi ulnaris tendon strip. A literature review showed only a few reported cases with varied methods for management. The technique utilised is analysed in comparison to the others. Level of Evidence: Level V (Therapeutic).

Diagnostic power of ChatGPT 4 in distal radius fracture detection through wrist radiographs.

Distal radius fractures rank among the most prevalent fractures in humans, necessitating accurate radiological imaging and interpretation for optimal diagnosis and treatment. In addition to human radiologists, artificial intelligence systems are increasingly employed for radiological assessments. Since 2023, ChatGPT 4 has offered image analysis capabilities, which can also be used for the analysis of wrist radiographs. This study evaluates the diagnostic power of ChatGPT 4 in identifying distal radius fractures, comparing it with a board-certified radiologist, a hand surgery resident, a medical student, and the well-established AI Gleamer BoneView™. Results demonstrate ChatGPT 4's good diagnostic accuracy (sensitivity 0.88, specificity 0.98, diagnostic power (AUC) 0.93), surpassing the medical student (sensitivity 0.98, specificity 0.72, diagnostic power (AUC) 0.85; p = 0.04) significantly. Nevertheless, the diagnostic power of ChatGPT 4 lags behind the hand surgery resident (sensitivity 0.99, specificity 0.98, diagnostic power (AUC) 0.985; p = 0.014) and Gleamer BoneView™(sensitivity 1.00, specificity 0.98, diagnostic power (AUC) 0.99; p = 0.006). This study highlights the utility and potential applications of artificial intelligence in modern medicine, emphasizing ChatGPT 4 as a valuable tool for enhancing diagnostic capabilities in the field of medical imaging.

[Diagnostics and classification of distal radius fractures]. / Diagnostik und Klassifikation der distalen Radiusfraktur.

Fractures of the distal radius show a wide spectrum of different fracture patterns. Although standard X­ray images are sufficient for extra-articular fractures, the exact analysis of intra-articular fractures requires the use of computed tomography (CT) with coronal, sagittal and axial sectional images. The classification is based on the Working Group for Osteosynthesis Questions (AO) criteria. The treatment strategy can be more precisely defined by a CT-based classification. Special attention must be paid to the presence of the key corners, as they have a high risk for primary or secondary dislocation if they not adequately stabilized.

[Basic principles of surgical treatment of distal radius fractures]. / Grundprinzipien der operativen Versorgung der distalen Radiusfraktur.

Distal radius fractures are one of the most frequent fractures of the upper extremities. The decision for conservative or surgical treatment is made after appropriate diagnostics using conventional radiographic and usually computed tomography imaging examinations. If the indications for surgical treatment are present, various options for reduction and fixation are available. The spectrum ranges from closed to open procedures up to accompanying arthroscopic support. Appropriate preoperative patient education about the procedure and the planned postinterventional treatment is essential. The goal of treatment is to restore wrist function while maintaining mobility and strength with a low risk of complications. All surgical procedures share the principle of reduction to restore anatomical relationship followed by fixation. Closed procedures include fixation with Kirschner wires and the construction of an external fixator. Volar locking plate osteosynthesis has become established in recent years as the method of choice for the majority of the fractures to be treated. For special fracture patterns and the treatment of accompanying injuries, arthroscopic support can be indicated. There is no uniform consensus on the best choice of procedure. This article discusses the possible procedures including the approaches, fixation techniques and specific follow-up treatment.

Fracture Dislocation of the Pisiform Bone in 14-Year-Old Boy-A Case Report.

We present the case of a 14-year-old patient who suffered fracture dislocation of the pisiform bone (PB) along with fractures of the scaphoid, proximal radius, and proximal phalanx of the thumb due to high-energy trauma directly to the extended wrist. This combination of fractures has not been previously reported in the literature. Currently, there is no consensus in the literature regarding the optimal treatment approach for such cases. In our management, initial attempts at closed and open reduction were unsuccessful, leading to the decision for primary pisiformectomy. Our report includes a follow-up of 3.5 years, demonstrating a very good outcome. Based on this case and a few similar published cases, primary pisiformectomy appears to be a viable and well-accepted option, particularly among young patients. Additionally, we conducted a review of radiographic criteria and management strategies for this specific injury and related conditions.

Deep learning performance compared to healthcare experts in detecting wrist fractures from radiographs: A systematic review and meta-analysis.

OBJECTIVE: To perform a systematic review and meta-analysis of the diagnostic accuracy of deep learning (DL) algorithms in the diagnosis of wrist fractures (WF) on plain wrist radiographs, taking healthcare experts consensus as reference standard. METHODS: Embase, Medline, PubMed, Scopus and Web of Science were searched in the period from 1 Jan 2012 to 9 March 2023. Eligible studies were patients with wrist radiographs for radial and ulnar fractures as the target condition, studies using DL algorithms based on convolutional neural networks (CNN), and healthcare experts consensus as the minimum reference standard. Studies were assessed with a modified QUADAS-2 tool, and we applied a bivariate random-effects model for meta-analysis of diagnostic test accuracy data. RESULTS: Our study was registered at PROSPERO with ID: CRD42023431398. We included 6 unique studies for meta-analysis, with a total of 33,026 radiographs. CNN performance compared to reference standards for the included articles found a summary sensitivity of 92% (95% CI: 80%-97%) and a summary specificity of 93% (95% CI: 76%-98%). The generalized bivariate I-squared statistic indicated considerable heterogeneity between the studies (81.90%). Four studies had one or more domains at high risk of bias and two studies had concerns regarding applicability. CONCLUSION: The diagnostic accuracy of CNNs was comparable to that of healthcare experts in wrist radiographs for investigation of WF. There is a need for studies with a robust reference standard, external data-set validation and investigation of diagnostic performance of healthcare experts aided with CNNs. CLINICAL RELEVANCE STATEMENT: DL matches healthcare experts in diagnosing WFs, which potentially benefits patient diagnosis.

The rate of nonunion in the MRI-detected occult scaphoid fracture.

Aims: There is a lack of published evidence relating to the rate of nonunion seen in occult scaphoid fractures, diagnosed only after MRI. This study reports the rate of delayed union and nonunion in a cohort of patients with MRI-detected acute scaphoid fractures. Methods: This multicentre cohort study at eight centres in the UK included all patients with an acute scaphoid fracture diagnosed on MRI having presented acutely following wrist trauma with normal radiographs. Data were gathered retrospectively for a minimum of 12 months at each centre. The primary outcome measures were the rate of acute surgery, delayed union, and nonunion. Results: A total of 1,989 patients underwent acute MRI for a suspected scaphoid fracture during the study period, of which 256 patients (12.9%) were diagnosed with a previously occult scaphoid fracture. Of the patients with scaphoid fractures, six underwent early surgical fixation (2.3%) and there was a total of 16 cases of delayed or nonunion (6.3%) in the remaining 250 patients treated with cast immobilization. Of the nine nonunions (3.5%), seven underwent surgery (2.7%), one opted for non-surgical treatment, and one failed to attend follow-up. Of the seven delayed unions (2.7%), one (0.4%) was treated with surgery at two months, one (0.4%) did not attend further follow-up, and the remaining five fractures (1.9%) healed after further cast immobilization. All fractures treated with surgery had united at follow-up. There was one complication of surgery (prominent screw requiring removal). Conclusion: MRI-detected scaphoid fractures are not universally benign, with delayed or nonunion of scaphoid fractures diagnosed only after MRI seen in over 6% despite appropriate initial immobilization, with most of these patients with nonunion requiring surgery to achieve union. This study adds weight to the evidence base supporting the use of early MRI for these patients.

Prognostic factors for clinical outcomes after arthroscopic treatment of traumatic central tears of the triangular fibrocartilage complex.

Aims: The study aimed to assess the clinical outcomes of arthroscopic debridement and partial excision in patients with traumatic central tears of the triangular fibrocartilage complex (TFCC), and to identify prognostic factors associated with unfavourable clinical outcomes. Methods: A retrospective analysis was conducted on patients arthroscopically diagnosed with Palmer 1 A lesions who underwent arthroscopic debridement and partial excision from March 2009 to February 2021, with a minimum follow-up of 24 months. Patients were assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, Mayo Wrist Score (MWS), and visual analogue scale (VAS) for pain. The poor outcome group was defined as patients whose preoperative and last follow-up clinical score difference was less than the minimal clinically important difference of the DASH score (10.83). Baseline characteristics, arthroscopic findings, and radiological factors (ulnar variance, MRI, or arthrography) were evaluated to predict poor clinical outcomes. Results: A total of 114 patients were enrolled in this study, with a mean follow-up period of 29.8 months (SD 14.4). The mean DASH score improved from 36.5 (SD 21.5) to 16.7 (SD 14.3), the mean MWS from 59.7 (SD 17.9) to 79.3 (SD 14.3), and the mean VAS pain score improved from 5.9 (SD 1.8) to 2.2 (SD 2.0) at the last follow-up (all p < 0.001). Among the 114 patients, 16 (14%) experienced poor clinical outcomes and ten (8.8%) required secondary ulnar shortening osteotomy. Positive ulnar variance was the only factor significantly associated with poor clinical outcomes (p < 0.001). Positive ulnar variance was present in 38 patients (33%); among them, eight patients (21%) required additional operations. Conclusion: Arthroscopic debridement alone appears to be an effective and safe initial treatment for patients with traumatic central TFCC tears. The presence of positive ulnar variance was associated with poor clinical outcomes, but close observation after arthroscopic debridement is more likely to be recommended than ulnar shortening osteotomy as a primary treatment.

Relation between the dash score and radiographic evaluation of the wrist in patients with wrist fracture.

Traditionally, the assessment of distal radius fracture outcomes has been based on radiological measurements and self-evaluation scores. However, there is uncertainty regarding how accurately these measurements reflect the patient's perception of their outcome. In this study, we examined the correlation between radiological measurements and patient-perceived outcomes using the Disabilities of the Arm, Shoulder, and Hand outcome (DASH) score. 140 individuals who had recovered from a distal radius fracture. and had been treated with DVR, Kapandji, percutaneous pinning or closed reduction were included in the study. The retrospective assessment included 78 females and 62 males, with a mean DASH score of 3.54 points.Except for the ulnar variance, the study found little to no significant association between the DASH score and the final radiological measurement.In summary, the DASH score did not always indicate that a superior radiological result translated into a better patient-perceived outcome.

Clinical Features and Classification of Proximal Carpal Fracture Dislocation Through the Radiocarpal Joint.

Background: The most common types of wrist dislocation are trans-scaphoid lunate dislocation (TLD) and trans-scaphoid perilunate dislocation, in which the lunate and proximal scaphoid are dislocated through the midcarpal joint. There is another rare type of dislocation in which the proximal carpi are dislocated through the radiocarpal joint. The purpose of this study is to examine the clinical features of this type of dislocation. Methods: Six cases of the proximal carpal fracture dislocation via the radiocarpal joint were retrospectively reviewed. All patients underwent open reduction and internal fixation with the ligament reconstruction. A Mayo wrist score was assigned to each patient based on the assessment of pain, functional status, range of motion and grip strength at the last follow-up. Clinical subjective evaluation of function and pain was assessed using the patient-rated wrist evaluation (PRWE) method. Results: All patients were male and injured with a median age of 33.5 years. The median follow-up period was 10 months. There were three types of dislocations: Scaphoid fracture dislocation, TLD and scaphoid-lunate dislocation. All patients had satisfactory results with an average PRWE of 7.2 ± 4.7. The preoperative VAS was 6.7 ± 1.0 and the postoperative VAS was 0.7 ± 0.7 (p < 0.01). Postoperative grip strength accounted for 89.2% ± 9.8% of the contralateral side; the Mayo wrist score averaged 90.0 ± 6.5, with four patients obtaining excellent and two good results. Conclusions: Fracture dislocation of the proximal carpal bones through the radiocarpal joint is an independent type of wrist dislocation that tends to occur in young men with high-energy impact. The wrist is most often injured in a pronation hyperextension position. If treatment is timely and appropriate, the prognosis is quite good. Level of Evidence: Level IV (Therapeutic).

External validation of the "deformity, edema, and pain in pronation" model for predicting wrist fractures.

BACKGROUND: The aim of this study is to externally validate the "Deformity, Edema, and Pain in Pronation" model, which determines the necessity for radiography in patients with wrist trauma. METHODS: This prospective, cross-sectional study was performed in a tertiary emergency department (ED). All patients admitted to the ED with wrist trauma aged 18 years and older were included in the study. Patients who did not have acute and blunt wrist trauma, those who could not be fully examined due to various reasons, and patients who did not wish to participate were excluded. Each patient was examined by their responsible physician, and imaging tests were requested based on the indications. All radiographic images were evaluated by an orthopedic surgeon who was blinded to the clinical information. This evaluation was accepted as the standard reference for diagnosing fractures. RESULTS: 391 patients were included in the study. 170 patients (43.5%) had at least one fracture. The sensitivity and specificity of the model formed in our study in predicting wrist fractures were 98.77% (95% CI: 95.61-99.85) and 27.60% (95% CI 21.82-34.00), respectively. The area under the receiver operating characteristic curve (AUC) on external validation of the model was 0.878 (p < 0.001; 95% CI: 0.844-0.913). With the practice of this rule, there would be a 16% decrease in X-ray imaging request, while only 0.5% patients would have missed inoperable fractures. CONCLUSION: The "deformity, edema, and pain in pronation" model is a reliable and practical clinical decision rule for determining the necessity of radiography in wrist trauma.

Ligamentoplasty using the ulnotriquetral ligament with wafer procedure for chronic triangular fibrocartilage complex foveal tear: Short-tem outcome.

BACKGROUND: We developed a new ligamentoplasty technique using the ulnotriquetral ligament (UTL) via a palmar approach for cases with dorsal instability of the ulna due to a foveal tear of the triangular fibrocartilage complex (TFCC). The study aimed to evaluate the clinical outcomes of this procedure. METHODS: We retrospectively analyzed 19 cases with foveal tears of TFCC who underwent the ligamentoplasty using UTL. We harvested the UTL from the triquetrum as a pedicle graft, avoiding damage of the connection between the base of the UTL and palmar radioulnar ligament (PRUL) as possible. The graft was flipped proximally and pulled out through the bone tunnel from the ulnar fovea to the ulnar neck, then fixed to the fovea using a tenodesis screw. The function of the TFCC can be reproduced by pulling out the UTL along with the PRUL through the ulnar fovea and re-establishing the PRUL tension. Clinical results were evaluated at least 12 months following surgery. The preoperative and postoperative wrist pain level on a neumerical rating scale (NRS), the radioulnar joint (DRUJ) ballottement test, the range of motion, the grip strength, and the Patient-rated wrist evaluation (PRWE) scores were evaluated. RESULTS: In all cases, the DRUJ ballottement test became negative at the final follow up compared with the normal side on manual examination. The pain levels significantly decreased as reflected by a decrease in NRS from 6.8 to 2.5 at final follow up (p < 0.01). The range of pronation/supination motion was improved from 149° to 157°. The mean PRWE score significantly decreased from 52.1 to 22.8 (p < 0.01). The postoperative pain level on the NRS scale of the three patients poorly improved. One case of the three with the 3 mm positive ulnar variance needed additional ulnar shaft shortening using a plate seven months after the primary procedure. CONCLUSIONS: The ligamentoplasty using UTL efficiently restored the ulnar palmar stability in all 19 cases and significantly decreased the wrist pain and the PRWE scores. STUDY DESIGN: Clinical, retrospective study.

Scaphoid nonunion: a novel modification of Matti-Russe technique with enhanced recovery and full clinical and radiographic union.

BACKGROUND: A scaphoid fracture is a common injury affecting the wrist joint. A fracture of the carpus scaphoid can heal uneventfully or be complicated by non-union. Scaphoid non-union can result in persistent wrist pain, and with functional difficulties affecting all activities of daily living of the patients, this disability is expected to be significant since most of these patients are young active adults. HYPOTHESIS: Extensive removal of the bone from the scaphoid, with the application of a large amount of cancellous bone graft and fixation with two to three wires, could lead to a high union rate and a good functional outcome. METHODS: Eighteen patients with scaphoid fracture non-union were recruited during their visit to the upper limb clinic at our institute. Demographic data were collected, and data regarding comorbidities, smoking, manual work, and others were recorded. Data regarding the interval between injury and surgery, time to radiographic union, and functional wrist scores were reported as well. RESULTS: A cohort of 18 patients was included. The mean age of patients was 30 years; most of our patients were healthy (83.3%), and more than two-thirds were smokers (72.2%). The mean follow-up time was 18 months (1.5 years), 15 patients (83.3%) achieved radiographic unions by 2-3 months, and the remaining 3 patients (16.7%) achieved radiographic unions by (4-5) months, i.e., all patients achieved successful radiographic unions by 5 months at maximum. The mean Mayo score for our series was 83.6 (± 12.4), with 5 patients (27%) achieved ≥ 95% which indicates a significantly high functioning wrist in our cohort. CONCLUSION: Our modified technique with enhanced stability from using three k-wires can achieve full clinical and radiographic unions and result in enhanced recovery postoperatively with cast immobilization limited to 6 weeks total. LEVEL OF EVIDENCE: IV Case series study.

Combined repair of scapholunate ligament (SL) and triangular fibrocartilage complex (TFCC) lesions in chronic trauma of the wrist: surgical treatment of 14 patients.

PURPOSE: Injuries of the scapholunate ligament (SL) and of the triangular fibrocartilage complex (TFCC) represent the main ligament injuries of the traumatic wrist. A double injury of the SL and TFCC ligaments is quite common in the trauma setting, and clinical examination is fundamental. MRI allows to detection of a TFCC and SL ligament injury, but wrist arthroscopy is still the gold standard for diagnosis. We present the clinical results of the combined reconstruction of chronic scapholunate ligament and TFCC injury. MATERIALS AND METHODS: Fourteen patients were treated at our hospital with a combined scapholunate ligament and TFCC complex repair. All patients were surgically treated by the same senior author, after a diagnostic arthroscopy that revealed a lesion of both structures. A comparison between the pre-operative and post-operative pain and function was carried out using VAS, Disability of Arm, Shoulder and Hand score (DASH) and Patient-Related Wrist/Hand Evaluation score (PRWHE). Wrist range of motion and strength were also compared following surgery. RESULTS: All patients had a mean follow-up of 54 months. A statistically significant improvement was observed both with the reduction in pain (VAS from 8.9 to 5) and with the improvement of functionality scores (DASH from 63 to 40 and PRWHE from 70 to 57) and with the increase in ROM and strength. In only one patient (7%), because of pain and instability, a supplement operation was needed (Sauve-Kapandji procedure) 3 months after the initial surgery. CONCLUSIONS: The simultaneous repair of the SL and TFCC complex has shown a good success rate in both decreasing pain and regaining functionality.