Ulnocarpal Abutment Syndrome With Triquetrum Degeneration.

We present the case of a 47-year-old patient with a congenital positive ulnar variance and elucidate its effects on nearby structures in relation to ulnocarpal abutment syndrome (UAS). While magnetic resonance imaging (MRI) helped to identify soft tissue changes in the wrist, the use of an arthrogram, in this case, allowed for a more comprehensive and detailed analysis of the ligaments and soft tissues. Image findings included a complex degenerative tear of the disc of the triangular fibrocartilage (TFCC), a degenerated triquetrum, and partial tears of the scapholunate and lunotriquetral ligaments. Mild dorsal angulation of the lunate was noted, representing dorsal intercalated segmental instability (DISI), suggesting scapholunate ligament injury. Palmar classification was utilized to classify the extent of the TFCC injury as Type IIE. This case shines a light on the presentation of UAS in a patient that was not the usual demographic affected by this pathology, as well as their UAS affecting the triquetrum rather than the more commonly associated lunate.

Magnetic Resonance Imaging (MRI) Not Inferior to the Gold Standard of Diagnostic Arthroscopy for Identification of Wrist Ligamentous Pathology.

Accurate diagnoses of wrist ligamentous injuries are critical to guiding the proper treatment pathway for patients with these pathologies. While advancements in imaging continue and magnetic resonance imaging (MRI) is valuable, diagnostic arthroscopy remains superior, particularly if involvement of the non-central triangular fibrocartilage complex (TFCC), scapholunate interosseous ligament (SLIL), or lunotriquetral interosseous ligament (LTIL) is suspected based on history and physical exam, and even in the face of negative MRI findings.

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).

Clinical Outcomes and Failure Rate of Triangular Fibrocartilage Complex Foveal Repair Were Comparable between Arthroscopic and Open Techniques.

Background: This study compared clinical outcomes between arthroscopic and open repair of triangular fibrocartilage complex (TFCC) foveal tears in chronic distal radioulnar joint (DRUJ) instability patients. Methods: A total of 79 patients who had gone through foveal repair of TFCC using arthroscopic technique (n = 35) or open technique (n = 44) between 2016 and 2020 were retrospectively analyzed. The visual analog scale (VAS) score for pain, active range of motion (ROM), grip strength, Mayo Modified Wrist Score (MMWS), Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire score, and Patient-Rated Wrist Evaluation (PRWE) score at 2-4-6-12-24 months postoperatively were compared between two groups. Results: Two years after the operation, clinical parameters (VAS, MMWS, DASH, and PRWE), grip strength, and ROM showed significant advancement in the two groups in comparison to their values measured preoperatively (p < 0.001). Nonetheless, we could not identify any statistically significant differences in the above clinical factors between the two groups. The arthroscopic group showed a better flexion-extension arc at 2 months and supination-pronation arc at 2 and 4 months than the open group (p < 0.001). There were no significant differences between the two groups at 2 years postoperatively. Ten patients (12.6%) had recurrent instability (three in the arthroscopic group and seven in the open group, p = 0.499). Similarly, both groups showed no significant difference in the return to work period. Conclusions: Arthroscopic foveal repair of TFCC provided similarly favorable outcomes and early recovery of pain and ROM compared to open repair.

The Effect of Arthroscopic Triangular Fibrocartilage Repair on Accompanying Extensor Carpi Ulnaris Tendinitis and Synovitis in Triangular Fibrocartilage Tears.

Purpose Management of ulnar-sided wrist pain is difficult due to the complexity of the anatomy and the similarity of the signs and symptoms of possible diagnoses. The study's main purpose is to examine the effect of arthroscopic triangular fibrocartilage (TFC) repair on untreated extensor carpi ulnaris (ECU) tendinitis and synovitis. Methods Thirteen patients who underwent arthroscopic TFC repair in our clinic and preoperatively demonstrated ECU tendon pathology with magnetic resonance imaging (MRI) were included in the retrospective study. Pre- and postoperative visual analog scale (VAS), pre- and postoperative tendinitis and synovitis, postoperative Mayo and patient-rated wrist evaluation score, postoperative grip strength of the operated and control sides, short and long diameters of the ECU tendon in ultrasonography were recorded. Results The mean age of 13 patients (9 females and 4 males) was 39.54 ± 13.54, and the mean follow-up period was 26 ± 7.25 months. While there was no significant difference between pre- and postoperative tendinitis or synovitis levels, VAS decreased significantly (8.46 ± 1.33 vs. 3.00 ± 2.31, p = 0.0016). While the grip strength was 21.78 ± 7.83 on the control side, it was 18.28 ± 7.51 on the surgery side, being significantly lower ( p = 0.0252). Ulnar variance did not affect tendinitis or synovitis. Short and long diameters of ECU were similar for the operated and control sides. While the short diameter did not affect the synovitis-tendinitis score, the bigger the long diameter, the higher the synovitis score (rho = 0.5162). Conclusion In the presence of ECU, tendon pathologies accompanying TFC lesions, additional surgical interventions are mandatory as arthroscopic TFC repair has no significant effect on the healing of ECU. Level of evidence : 4.

[Concomitant injuries of the wrist, distal ulna and distal radioulnar joint in distal radius fractures : Primary operative cotreatment vs. healing with no additional treatment]. / Begleitende Verletzungen von Karpus, distaler Elle und distalem Radioulnargelenk bei distaler Radiusfraktur : Primäre operative Mitversorgung vs. Heilung ohne zusätzliche Therapie.

Distal radius fractures are the most common fractures in adults and account for one quarter of all fractures, with increasing incidence. The number of patients and the requirement of an exact treatment are high. Continuous developments in diagnostic and operative possibilities enable in many cases a high-quality treatment with good clinical outcome; however, radius fractures rarely occur alone but in combination with additional fractures or ligamentous injuries. The frequency and extent of these injuries are not linked to the complexity of the primary injury. The aim is to recognize and correctly diagnose potential concomitant injuries. Many injuries do not need immediate treatment but heal without additional treatment after the radius has been treated. It is important to recognize those injuries which can cause severe complications if untreated; however, exactly this is often difficult. In many cases there is still no consensus if and how concomitant injuries should be treated. This article highlights the most frequent concomitant injuries in distal radius fractures with the possible advantages and disadvantages of cotreatment in order to facilitate decision making.

The "Bubble Test" in the Arthroscopic Diagnosis of Triangular Fibrocartilage Central Lesion: Description and Relevance to Treatment.

Background Ulnarly sided wrist pain is a common and challenging symptom. Arthroscopy has become a safe and effective tool for the correct diagnosis and treatment, proving to be better than all other clinical and imaging diagnostic methods. Some tests have been described for the diagnosis of triangular fibrocartilage (TFC) lesions, such as the trampoline test for peripheral lesions and the hook, ghost, and suction tests for foveal detachments. In tears at the disc level, when they affect all layers of the TFC (complete lesion) at the same point, testing with the probe will usually suffice for the diagnosis. However, in some apparently partial lesions, the probe cannot pass through all layers because the proximal and distal sites of the lesion are not aligned. There has been no arthroscopic test described for such cases. Case Description We describe a simple and practical test that we have called the "bubble test" in a typical case to diagnose TFC central injuries, aiming to discriminate partial from complete lesions, which are eventually hard to differentiate through direct vision and arthroscopic probing, leading to a direct influence onto the treatment. The bubble test is performed with external compression of the distal radioulnar joint (DRUJ) aspect, with the thumb on the back of the DRUJ and the index and middle fingers onto the volar aspect. The abrupt compression of this region causes the passage of air mixed with synovial fluid from the DRUJ to the radiocarpal joint, generating bubble formation. Clinical Relevance The bubble test should correlate to physical examination and imaging (magnetic resonance imaging [MRI]) findings and is particularly useful in central and degenerative (Type II) TFC lesions in patients complaining of chronic pain on the ulnar region of the wrist, with no history of trauma and with inconclusive MRI findings. Once the diagnosis is confirmed, arthroscopic treatment consists of wide debridement of the lesion with resection of the injured tissue and the local inflammatory reaction. Thus, it is essential for the correct treatment to define the exact location of the lesion and to know whether the disc injury is complete.

Current concepts and new trends in management of isolated triangular fibrocartilage complex injuries.

The triangular fibrocartilaginous complex is made of multiple components, of which the palmar and dorsal radioulnar ligaments play an important role in distal radioulnar joint stability. The ulnar wrist ligaments may be injured during forearm and wrist trauma. There are several aspects of triangular fibrocartilaginous complex management that are still open to debate. The aim of the present study was to review the current concepts and discuss emerging trends to better elucidate and treat this important ligament complex.Level of evidence: V.

Review and update on the management of triangular fibrocartilage complex injuries in professional athletes.

Triangular fibrocartilage complex injuries are common in amateur and professional sports. These injuries are mainly caused by acute or chronic repetitive axial loads on the wrist, particularly on the ulnar side and in association with rotations or radial/ulnar deviations. In order to treat professional athletes, a detailed specific knowledge of the pathology is needed. Moreover, the clinician should fully understand the specific and unique environment and needs of the athletes, their priorities and goals, the type of sport, the time of the season, and the position played. An early diagnosis and appropriate management with the quickest possible recovery time are the uppermost goals for both the athlete and the surgeon. A compromise between conservative vs surgical indications, athletes' needs and expectations, and financial implications should be achieved. Arthroscopic procedures should be timely planned when indicated as they could allow early diagnosis and treatment at the same time. Conservative measures are often used as first line treatment when possible. Peripheral lesions are treated by arthroscopic repair, whilst central lesions are treated by arthroscopic debridement. Further procedures (such as the Wafer procedure, ulnar osteotomies, etc.) have specific indications and great implications with regard to rehabilitation.

Complications after arthroscopic triangular fibrocartilage complex (TFCC) surgery.

Wrist arthroscopy is a valuable and widely utilized tool in the treatment of triangular fibrocartilage complex (TFCC) injuries. These procedures include synovectomy alone, peri-capsular or transosseous repair, and arthroscopic-assisted reconstruction, and each are associated with specific complications. This review describes the types of complications and their rates in different types of arthroscopic TFCC surgery reported in the literature and in our centre. Across the spectrum of arthroscopic TFCC surgery, complication rates and the learning curve increase with surgical complexity. Relevant anatomy, prevention and management of complications including nerve injury and irritation, extensor tendon injury and tendinitis, fracture, stiffness, and persistence of symptoms or instability are discussed. Vigilance to anatomical details and careful dissection can help to reduce complications that may result in disturbing pain and functional loss.

Dynamic Computed Tomography of the Distal Radioulnar Joint Versus Magnetic Resonance Imaging in Detecting Foveal Tears of the Triangular Fibrocartilage Complex.

BACKGROUND: Diagnosis of foveal triangular fibrocartilage complex (TFCC) tears remains difficult. The purpose of this study was to evaluate whether dynamic computed tomography (CT) of the distal radioulnar joint (DRUJ) has a higher sensitivity in detecting foveal tears of the TFCC when compared with magnetic resonance imaging (MRI). METHODS: A database query identified all patients above the age of 18 years with suspected foveal TFCC injuries who underwent bilateral dynamic CT imaging of the DRUJ, static 3T MRI, and subsequent wrist arthroscopy. All patients had evidence of foveal tenderness on clinical examination. The imaging results were validated with wrist arthroscopy. RESULTS: Twelve patients with a mean age of 31 years (range, 18-53 years) were identified. Eight patients were diagnosed with a complete foveal detachment of the TFCC on wrist arthroscopy. Of the 8 patients with a foveal tear on DRUJ arthroscopy, only 3 had a preoperative physical examination suggestive of DRUJ instability. Magnetic resonance imaging identified foveal injuries in 4 of these 8 patients (sensitivity, 50%), and 3 of these were identified as only partial tears. Dynamic CT identified instability of DRUJ in 6 of 8 patients (sensitivity, 75%). Seven of 8 patients had imaging findings suggestive of a foveal tear when including either MRI or CT imaging (sensitivity, 88%). Of the 4 patients with an intact foveal attachment on arthroscopy, 3 (specificity, 75%) had a stable DRUJ on CT and all 4 (specificity, 100%) had an intact foveal attachment on MRI. CONCLUSION: Sixty-two percent of patients with foveal tears on arthroscopy have a stable DRUJ on clinical examination. When combining MRI and dynamic CT imaging of the DRUJ, the sensitivity of detecting a foveal TFCC tear approaches 88% compared with a gold standard of wrist arthroscopy.

Fracture Severity and Triangular Fibrocartilage Complex Injury in Distal Radius Fractures with or without Osteoporosis.

The purpose of this study was to investigate the fracture morphology of distal radius fractures (DRFs) with the status of triangular fibrocartilage complex (TFCC) foveal insertion in patients with or without osteoporosis and to identify the relationship between osteoporosis and foveal tear. Seventy-five patients who underwent surgery for DRF from January 2021 to September 2023 were included. All patients were evaluated by standard radiography and dual-energy X-ray absorptiometry and underwent a 3.0 T magnetic-resonance imaging examination of the involved wrist to identify TFCC foveal tear. Patients were allocated into two groups according to the presence of osteoporosis: patients with osteoporosis (group I) and those without osteoporosis (group II). Group I showed a significantly larger displacement of fractures compared to group II (radial inclination; 13.7 ± 5.4 vs. 17.9 ± 4.2; p < 0.001, dorsal angulation; 22.2 ± 12.1 vs. 16.5 ± 9.4; p = 0.024, ulnar variance; 4.15 ± 2.1 vs. 2.2 ± 1.9; p < 0.001). Dorsal angulation and ulnar variance were found to be independent prognostic factors for TFCC foveal tear in logistic regression analysis. Displacement of fractures was related to osteoporosis, and dorsal angulation and ulnar variance were independent prognostic factors for TFCC foveal tear. However, osteoporosis was not identified as a factor associated with TFCC foveal tears.

The Hook Test Is Not Pathognomonic for Foveal Detachment of the Triangular Fibrocartilage.

Background The integrity of the foveal insertion of the triangular fibrocartilage complex (TFCC) is currently assessed by inference using the hook test. Using dry arthroscopic techniques, the primary author observed that many patients with painful distal radioulnar joint (DRUJ) instability and a positive hook test had an intact foveal insertion. This study was performed to determine whether a positive hook test is a reliable index of a tear of the foveal insertion. Technique The hook test is performed using a probe to elevate the TFCC off the ulna head toward the articular surface of the lunate. In this study, the hook test was considered positive if the TFCC could be elevated to bridge more than 80% of the space between the TFCC and the articular surface of the lunate. Patients and Methods A retrospective study was performed using the medical records and arthroscopic videos of 113 patients who had clinical signs of DRUJ instability and underwent arthroscopic surgery performed by the primary author in 2020. It was documented whether the hook test was positive or negative, whether the foveal insertion was intact, abnormal or absent, and whether there were peripheral (dorsal or volar) tears of the TFCC. Sensitivity and specificity were calculated using arthroscopic findings as the reference standard. Results The sensitivity of the hook test was found to be 100%, and the specificity was 7.0%. The positive predictive value for foveal pathology was found to be 12.3% and the negative predictive value 100%. The diagnostic accuracy of the hook test in determining the presence of foveal tears was found to be 17.7%. The diagnostic accuracy of the hook test in determining the presence of a TFCC abnormality was 99.1%. Conclusions A positive hook test is indicative of a tear of the TFCC, but it is not anatomically specific for a tear of the foveal insertion. To reliably assess the foveal insertion, it must be visualized and probed using dry arthroscopic techniques.

All-Arthroscopic Foveal Triangular Fibrocartilage Complex Tendon Reconstruction.

Background In symptomatic chronic injury of ulnar-sided tear of the triangular fibrocartilage complex, reconstruction techniques involving foveal reconstruction with palmaris longus tendon graft using the method described by Bain have been described with good outcomes. Description of Technique With increasing popularity of wrist arthroscopy to address various wrist pathologies, we present our technique of arthroscopic foveal reconstruction. We also include a step-by-step description of the procedure with illustrations, with aims to aid surgeons in executing it Conclusion Unlike other arthroscopic techniques described, this involves single osseous ulnar tunnel and performed completely arthroscopically, allowing an end result similar to Bain's open technique.

Effectiveness of suture anchor and transosseous suture technique in arthroscopic foveal repair of the triangular fibrocartilage complex: a systematic review.

BACKGROUND: Currently, there were two major surgical methods for arthroscopic triangular fibrocartilage complex (TFCC) foveal repair: suture anchor (SA) and transosseous suture (TOS). The purpose of this systematic review is to examine the relevant outcome improvement and safety of SA and TOS technique. METHODS: Literature review of electronic databases for studies investigating the effects of SA and TOS in patients undergoing arthroscopic TFCC foveal repair was performed. We compared the pre-operative and postoperative functional outcomes, clinical outcomes [pain, range of motion (ROM) and grip strength], and complications of two methods. Minimal clinically important difference (MCID) was used to determine clinically meaningful improvement. RESULTS: There were 1263 distinct studies identified, with 26 (904 patients) meeting the inclusion criteria. The mean age of participants ranged from 21.4 to 41 years, and the mean follow-up time ranged from 6 to 106 months. Both SA and TOS groups reported significant improvement in the modified mayo wrist score, the disabilities of the arm, shoulder, and hand (DASH) score, quick DASH score, patient-reported wrist evaluation (PRWE) score, and the visual analog scale (VAS) score. According to MCID, all the studies from both groups reporting DASH, quick DASH, PRWE and VAS score achieved clinically meaningful improvement. (MCID: 10 for DASH, 14 for quick DASH, 14 for PRWE and 1.6-18 for VAS). The ROM changes in both groups varied from improvement to deterioration. Grip strength improved in both SA and TOS group. Most complications were self-limited. The reoperation rates in SA and TOS ranged from 0 to 20% and 0 to 27.3%, respectively. CONCLUSIONS: Both SA and TOS technique for arthroscopic TFCC foveal repair could achieve improvement in postoperative functional outcomes, pain, and grip strength with low reoperation rate. However, the ROM improvement was still inconclusive. LEVEL OF EVIDENCE IV: Systematic review of level III and IV studies.

A Modified Arthroscopic Ulnar Tunnel Technique for Combined Foveal and Capsular (All-Inside) Fixation of Triangular Fibrocartilage Complex Injury.

Background Traumatic disruption of the triangular fibrocartilage complex (TFCC) is commonly present in various wrist traumas. A variation of surgical techniques is previously developed for different injury patterns. To our knowledge, only a few studies have investigated the fixation of combined foveal and capsular TFCC injuries using the ulnar tunnel technique. Purpose This prospective cohort study of 21 patients aimed to evaluate the clinical and patient-reported outcome at 2 years of follow-up after arthroscopic TFCC of combined, foveal, and capsular reattachment by modified ulnar tunnel technique. Methods Pain, grip strength, wrist motion, inclusive rotation, and patient-reported outcomes were assessed pre- and postoperatively at 2 years of follow-up. Results No complications occurred preoperatively. Pain and patient-reported outcomes improved significantly ( p < 0.0001 and 0.004). Grip strength improved, but not significantly ( p = 0.088). The range of motion remained unchanged. All the patients achieved full stability of the distal radioulnar joint. Two patients sustained a new TFCC injury due to a wrist trauma and underwent a reoperation successfully. Two patients experienced complications: one patient experienced tenderness caused by cyst occurrence after PushLock ankers and the second had subluxation of the extensor carpi ulnaris tendon subsheet. Both patients were successfully treated and reoperated on with curettage of the cyst, and reconstruction of the extensor carpi ulnaris retinaculum. All the patients ended with good or excellent satisfaction scores. Conclusion The ulnar tunnel technique for combined foveal and capsular injuries shows promising short-term follow-up results and high satisfaction scores in the patients. Level of Evidence II (Prospective Corhorte).

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.

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.

Foveal triangular fibrocartilage complex pathology: a potentially under-recognized injury.

The primary aim of the present study was to present a case series of 24 patients with foveal triangular fibrocartilage complex (TFCC) injuries that were treated with arthroscopically assisted TFCC foveal repair. In total, 19 patients had a stable distal radioulnar joint (DRUJ) and five had an unstable DRUJ. Despite this, all patients were found to have a foveal tear upon DRUJ arthroscopy. Magnetic resonance imaging (MRI) scans detected only eight out of 23 patients with foveal injuries. In addition to their foveal injury, 19 of the 24 patients had additional pathology that required treatment. At a mean follow-up of 18 months, there was a statistically significant improvement in pain, range of motion, grip strength and functional scores. In this study, we demonstrate that having a stable DRUJ upon clinical examination and normal MRI findings does not rule out foveal TFCC injury and a high index of clinical suspicion is needed when managing patients with ulnar sided wrist pain.Level of evidence: IV.