Reliability and Validity of the Hook Test for Diagnosis of Distal Biceps Tendon Ruptures.

PURPOSE: Although the initial description of the distal biceps tendon (DBT) hook test (HT) reported 100% sensitivity (Sn) and specificity (Sp), subsequent retrospective series have demonstrated imperfect validity. The purpose of this investigation was to prospectively assess the validity and reliability of the HT for complete DBT ruptures. We aimed to determine the Sn/Sp and interrater reliability for the HT. METHODS: A consecutive series of adult patients presenting to our outpatient clinics with an elbow complaint was prospectively examined. Patients were included if they had undergone advanced imaging (magnetic resonance imaging or ultrasound) that imaged the DBT and underwent DBT repair. There were four participating surgeons, all of whom were blinded to magnetic resonance imaging/ultrasound prior to performing the HT. To determine the Sn/Sp of the HT and advanced imaging, intraoperative findings served as the primary reference standard. The interrater reliability of the HT was calculated for cases in which a primary examiner (surgeon) and secondary examiner (physician assistant or resident) performed the HT. RESULTS: Of 64 patients who had undergone advanced imaging, 28 (44%) underwent DBT surgery and were included in the assessment of Sn/Sp. The mean age was 49 years, and all patients were men. The Sn and Sp of the HT were 96% and 67%, respectively. Advanced imaging demonstrated 100% Sn and Sp. Twenty-five patients were evaluated by a primary and secondary examiner. The interrater reliability was substantial (Cohen kappa, 0.71). CONCLUSIONS: The Sn and Sp of the HT were 96% and 67%, respectively, when assessed prospectively. Advanced imaging findings (magnetic resonance imaging/ultrasound) demonstrated 100% Sn and Sp. The HT can be performed reliably by examiners with varying experience levels. Considering the imperfect validity of the HT, we caution against the use of this examination alone to diagnose DBT ruptures. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.

Arthroscopic assessment of syndesmotic instability: Are we pulling correctly in the coronal plane?

BACKGROUND: While the lateral hook test (LHT) has been widely used to arthroscopically evaluate syndesmotic instability in the coronal plane, it is unclear whether the angulation of the applied force has any impact on the degree of instability. We aimed to determine if changing the direction of the force applied while performing the LHT impacts the amount of coronal diastasis observed in subtle syndesmotic injuries. METHODS: In 10 cadaveric specimens, arthroscopic evaluation of the syndesmotic joint was performed by measuring anterior and posterior-third coronal plane diastasis in the intact state, and repeated after sequential transection of the 1) anterior inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior inferior tibiofibular ligament (PITFL). In all scenarios, LHT was performed under 100 N of laterally directed force. Additionally, LHT was also performed under: 1) anterior inclination of 15 degrees and 2) posterior inclination of 15 degrees in intact and AITFL+IOL deficient state. RESULTS: Compared to the intact state, the syndesmosis became unstable after AITFL +IOL transection under laterally directed force with no angulation (p = 0.029 and 0.025 for anterior and posterior-third diastasis, respectively), which worsened with subsequent PITFL transection (p = <0.001). Moreover, there was no statistical difference in anterior and posterior-third coronal diastasis in both intact and AITFL+IOL deficient states under neutral, anterior, and posteriorly directed force (p-values ranging from 0.816 to 0.993 and 0.396-0.80, respectively). However, in AITFL+IOL transected state, posteriorly directed forces resulted in greater diastasis than neutral or anteriorly directed forces. CONCLUSIONS: Angulation of the applied force ranging from 15 degrees anteriorly to 15 degrees posteriorly during intraoperative LHT has no effect on coronal plane measurements in patients with subtle syndesmotic instability. On the other hand, posteriorly directed forces result in more sizable diastasis, potentially increasing their sensitivity. CLINICAL RELEVANCE: When arthroscopically evaluating subtle syndesmotic instability, clinicians should assess coronal diastasis with the hook angled 15 degrees posteriorly.

Reliability of preoperative CT and intraoperative manual tests in syndesmosis injury.

OBJECTIVE: We always confirm the diagnosis of syndesmotic injury with a Hook test for all ankle fractures and fixed if necessary. Then, we noticed a discrepancy between preoperative radiology and the Hook test. Moreover, we want to report the reliability of syndesmotic fixation decisions with Hook test and preoperative radiology. METHODS: A total of 37 surgically treated patients with isolated Weber type C ankle fractures were included in the study. In all patients, the syndesmosis joint was injured in preoperative computed tomography and X-ray imaging. However, only patients with (+) Hook tests had undergone a syndesmosis fixation. Patients were divided into two groups: Group A: Hook tests (+) and Group B: Hook test (-). Also, the groups were compared according to clinical outcomes with the Visual Analog Scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS), and foot and ankle disability index (FADI) scores. RESULTS: The mean participant age was 39 (19-80) years, and the mean follow-up period was 47.27 (22-68) months. Groups A and B consisted of 17 (45.9%) and 20 (54.1%) patients, respectively. The mean VAS, AOFAS, and FADI scores were 17.7±14.3, 90.32±8.06, and 92.9±6.88, respectively. "Excellent" and "good" results were found in 34 (%91.8) patients according to AOFAS nad FADI. The malreduction rate was 8.1% in all patients, 5% in group A, and 11.8% in group B. No statistically significant differences in final functional scores were found between groups A and B. CONCLUSION: Hook test is reliable and adequate for evaluating the stability and quality of syndesmosis reduction. Weber type C lateral malleolar fractures in the decision of syndesmosis fixation; although syndesmosis injury is diagnosed in preoperative radiology, we recommend that the diagnosis be confirmed with the Hook test.

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.

Arthroscopic Assessment of Syndesmotic Instability in the Sagittal Plane in a Cadaveric Model.

BACKGROUND: Syndesmotic instability is multidirectional, occurring in the coronal, sagittal, and rotational planes. Despite the multitude of studies examining such instability in the coronal plane, other studies have highlighted that syndesmotic instability may instead be more evident in the sagittal plane. The aim of this study was to arthroscopically assess the degree of syndesmotic ligamentous injury necessary to precipitate fibular translation in the sagittal plane. METHODS: Twenty-one above-knee cadaveric specimens underwent arthroscopic evaluation of the syndesmosis, first with all syndesmotic and ankle ligaments intact and subsequently with sequential sectioning of the anterior inferior tibiofibular ligament (AITFL), the interosseous ligament (IOL), the posterior inferior tibiofibular ligament (PITFL), and deltoid ligament (DL). In all scenarios, an anterior to posterior (AP) and a posterior to anterior (PA) fibular translation test were performed under a 100-N applied force. AP and PA sagittal plane translation of the distal fibula relative to the fixed tibial incisura was arthroscopically measured. RESULTS: Compared with the intact ligamentous state, there was no difference in sagittal fibular translation when only 1 or 2 ligaments were transected. After transection of all the syndesmotic ligaments (AITFL, IOL, and PITFL) or after partial transection of the syndesmotic ligaments (AITFL, IOL) alongside the DL, fibular translation in the sagittal plane significantly increased as compared with the intact state (P values ranging from .041 to <.001). The optimal cutoff point to distinguish stable from unstable injuries was equal to 2 mm of fibular translation for the total sum of AP and PA translation (sensitivity 77.5%; specificity 88.9%). CONCLUSION: Syndesmotic instability appears in the sagittal plane after injury to all 3 syndesmotic ligaments or after partial syndesmotic injury with concomitant deltoid ligament injury in this cadaveric model. The optimal cutoff point to arthroscopically distinguish stable from unstable injuries was 2 mm of total fibular translation. CLINICAL RELEVANCE: These data can help surgeons arthroscopically distinguish between stable syndesmotic injuries and unstable ones that require syndesmotic stabilization.

Distal biceps hook test - Sensitivity in acute and chronic tears and ability to predict the need for graft reconstruction.

BACKGROUND: The aim of this study was to assess the sensitivity of distal biceps hook test - O'Driscoll hook test - in a retrospective series of acute and chronic distal biceps tendon tears and investigate the ability of the test to predict the need for graft reconstruction. METHODS: We retrospectively evaluated 234 consecutive distal biceps tendon tears operated in a single centre. The result of O'Driscoll hook test and perioperative findings of distal biceps were documented in standard fashion. RESULTS: The perioperative and O'Driscoll hook test data were available in 202 cases. The sensitivity for the distal biceps hook test was 78% in all tears and 83% in complete tears. The sensitivity was significantly lower in partial tears (30%) and in cases where lacertus fibrosus was found to be intact (45 %). When O'Driscoll hook test was positive and the delay from initial injury to operative intervention was eight weeks or more, there was over 75% probability of achilles tendon allograft reconstruction. When O'Driscoll hook test was negative, the probability of reconstruction even after 12 weeks' delay was only 20%. DISCUSSION: O'Driscoll hook test is useful when establishing distal biceps tendon tear diagnosis, but a negative test does not exclude rupture. In delayed cases, a positive test may predict the need for reconstruction.

Finite element analysis of the influence of anterior talofibular ligament injury on Hook test results.

AIM: To determine whether the anterior talofibular ligament injury will influence the Hook test result. METHOD: A three-dimensional model of the ankle was established based on CT scan of a healthy volunteer and ligament attachment through references; Four groups (A-D) of operating conditions were set up. In group A, the anterior and posterior ligaments of the inferior tibiofibular joint were cut off and the anterior talofibular ligament was kept intact; in group B, all the anterior and posterior tibiofibular ligaments and the anterior talofibular ligament were cut off; in group C, the medial and lateral ligaments of the ankle joint and the inferior tibiofibular ligament were kept intact; in group D, only the talofibular ligament was cut off and other ligaments were kept intact. The proximal end of the model was restrained in all four groups, an outward pulling force of 100N perpendicular to the fibula was applied, and displacement and rotation of the distal end of the fibula in the four groups was observed. RESULTS: When the inferior tibiofibular joint injury was associated with an anterior talofibular ligament injury, the Hook test indicated about 3.19mm of displacement of the distal end of the fibula, and obvious external rotation occurred due to increased activity of the anterior border of the fibula. In the other groups, a single inferior tibiofibular joint injury or a single anterior talofibular ligament injury did not increase displacement or rotation of the distal end of the fibula.

Effect of Sequential Sectioning of Ligaments on Syndesmotic Instability in the Coronal Plane Evaluated Arthroscopically.

BACKGROUND: Arthroscopic evaluation of the syndesmosis allows direct visualization of syndesmotic instability. The purpose of this study was to determine the minimum degree of ligamentous injury necessary to destabilize the syndesmosis in the coronal plane when assessed arthroscopically and pinpoint where such instability should be measured within the incisura. METHODS: Fourteen cadaveric specimens were divided into 2 groups and arthroscopically assessed first with the syndesmosis intact and then following serial differential ligamentous transection. Group 1 (n = 7): anterior-inferior tibiofibular (AITFL), interosseous (IOL), posterior-inferior tibiofibular (PITFL), and deltoid (DL) ligament. Group 2 (n = 7): PITFL-IOL-AITFL-DL. At each step, a standard 100-N lateral hook test was applied and tibiofibular coronal plane diastasis measured arthroscopically at both the anterior and posterior third of the incisura. These measurements were in turn compared with those of the stressed intact ligamentous state. RESULTS: There was no significant syndesmotic instability measured at either the anterior or posterior margin of the incisura after transection of a singular ligament (AITFL or PITFL) or after the IOL was additionally transected. Diastasis at the posterior margin was significantly increased when all syndesmotic ligaments were sectioned (group 1: P = .018; group 2: P = .008), but this was not noted along the anterior margin. Diastasis at the anterior margin reached significance only with complete transection of syndesmosis and DL (group 1: P < .001; group 2: P = .044). CONCLUSION: Under arthroscopic evaluation, the syndesmosis becomes unstable in the coronal plane only when all syndesmotic ligaments are transected, which should preferentially be measured at the posterior margin of the incisura. Anteriorly, diastasis becomes apparent only with addition of DL disruption, although this added finding may aid in diagnosis of occult deltoid injury. CLINICAL RELEVANCE: AITFL, IOL, and PITFL need to be injured to produce coronal plane syndesmotic instability. Arthroscopic assessment of such instability should occur along the posterior margin of the incisura. When they exist, similar findings anteriorly suggest concomitant deltoid injury.