Scapholunate dissociation; diagnostics made easy

Gantry-free cone-beam CT arthrography for diagnosis of scapholunate ligament injuries: accelerating the preoperative work-up in acute wrist trauma

OBJECTIVE

Combining fluoroscopy and high-resolution cone-beam CT (CBCT) in a multipurpose scanner without a conventional gantry holds the potential for time-saving in musculoskeletal interventions. This study investigated the performance of gantry-free CBCT arthrography in patients with suspected scapholunate ligament (SLL) tears.

MATERIALS AND METHODS

Fifty-five patients (29 men, 46.0 ± 15.3 years) who underwent preoperative gantry-free CBCT arthrography between June 2021 and March 2024 were analyzed retrospectively. Three radiologists assessed CBCT arthrograms for tears of the palmar and dorsal SLL segments. Surgical reports served as the reference standard for calculating indicators of diagnostic accuracy. Interreader agreement was tested by computing Krippendorff α. Radiation dose and examination time were recorded.

RESULTS

Tears of the palmar and dorsal SLL segment were recorded in 25 (45%) and 6 patients (11%), respectively. CBCT arthrography facilitated good sensitivity (range for all readers: 84-92%) and excellent specificity (93-97%) in the assessment of the palmar SLL. For the dorsal SLL, sensitivity (83-100%) and specificity (96-98%) were even higher. Substantial agreement was determined for both the palmar (α = 0.83, 95% CI: 0.74-0.90) and dorsal SLL (0.84, 0.70-0.95). The mean volume CT dose index for CBCT arthrography was 3.2 ± 1.4 mGy. Not requiring patient repositioning, the median time between fluoroscopy-guided contrast injection and CBCT was 3:05 min (2:31-3:50 min).

CONCLUSION

Gantry-free CBCT arthrography allows for excellent accuracy in the preoperative diagnosis of SLL tears with low radiation dose. The ability to alternate between fluoroscopy and CBCT without repositioning facilitates a "one-stop-shop" approach with short examination time.

KEY POINTS

Question Performing fluoroscopy-guided arthrography and high-resolution cone-beam CT without patient repositioning appears advantageous for the preoperative work-up of distal radius fractures with concomitant scapholunate ligament injuries. Findings Gantry-free cone-beam CT arthrography allowed for short examination times and high diagnostic accuracy for either segment of the scapholunate ligament (89-98% versus surgery). Clinical relevance Preoperative assessment of scapholunate instability influences treatment since surgeons can reduce radius fractures and perform osteosynthesis via a dorsal portal to simultaneously stabilize the scapholunate compartment or use an additional dorsal access route for ligament suture and transfixation.

Post-processing of quantitative 4D-CT for initial evaluation of scapholunate Instability: Assessment of simplified approaches to data analysis

OBJECTIVES

To evaluate the diagnostic performance of simplified post-processing approaches for quantitative wrist 4D-CT in the assessment of scapholunate instability (SLI).

METHODS

A prospective monocentric case-control study included 60 patients with suspected post-traumatic scapholunate ligament (SLL) tears and persistent pain. Of these, 40 patients exhibited SLL tears, subdivided into two groups of 20 each: one group with completely torn ligaments and the other with partially torn ligaments. The remaining 20 patients, whose SLLs were intact, served as controls. 4D-CT and CT arthrography were performed, and post-processed by two readers using three approaches: the standard method with full data assessment and dedicated software, partial data assessment with post-processing software (bone locking), and partial data assessment without post-processing software (no bone locking). The scapholunate gap (SLG) parameter was measured in millimeters to evaluate scapholunate diastasis during radioulnar deviation (RUD). The scapholunate ligament status on CT arthrography was considered the gold standard.

RESULTS

The SLG-derived parameters (range, mean, and maximal values) were significantly increased in patients with both intact and torn scapholunate ligaments across all post-processing approaches (P values ranging from 0.001 to 0.004). SLG range was the best parameter for diagnosing SLL tears, with ROC AUC values ranging from 0.7 to 0.88 across the three post-processing methods. The interobserver reproducibility was better with the alternative approaches (ICC values 0.93-0.96) compared to the standard approach (ICC values 0.65-0.72). Additionally, post-processing time was shorter with the alternative approaches, especially when specific software was not used (reduced from 10 to three minutes).

CONCLUSION

Simpler approaches to wrist 4D-CT data analysis yielded acceptable diagnostic performances and improved interobserver reproducibility compared to the standard approach.

A scoping review to map evidence regarding key domains and questions in the management of non-traumatic wrist disorders

Introduction

Non-traumatic wrist disorders (NTWD) are commonly encountered yet sparse resources exist to aid management. This study aimed to produce a literature map regarding diagnosis, management, pathways of care and outcome measures for NTWDs in the United Kingdom.

Methods

An interdisciplinary team of clinicians and academic researchers used Joanna Briggs Institute guidelines and the PRISMA ScR checklist in this scoping review. A mixed stakeholder group of patients and healthcare professionals identified 16 questions of importance to which the literature was mapped. An a-priori search strategy of both published and non-published material from five electronic databases and grey literature resources identified records. Two reviewers independently screened records for inclusion using explicit eligibility criteria with oversight from a third. Data extraction through narrative synthesis, charting and summary was performed independently by two reviewers.

Results

Of 185 studies meeting eligibility criteria, diagnoses of wrist pain, De Quervain's syndrome and ulna-sided pain were encountered most frequently, with uncontrolled non-randomised trial or cohort study being the most frequently used methodology. Diagnostic methods used included subjective questioning, self-reported pain, palpation and special tests. Best practice guidelines were found from three sources for two NTWD conditions. Seventeen types of conservative management, and 20 different patient-reported outcome measures were suggested for NTWD.

Conclusion

Substantial gaps in evidence exist in all parts of the patient journey for NTWD when mapped against an analytic framework (AF). Opportunities exist for future rigorous primary studies to address these gaps and the preliminary concerns about the quality of the literature regarding NTWD.

Concomitant ligament injuries can be left untreated during surgery of distal radial fractures

Instability of the distal radioulnar joint and scapholunate dissociation may cause pain, functional impairment and subsequent arthrosis. There is no consensus about whether these injuries should be treated acutely in patients undergoing surgery for distal radial fractures. We conducted a prospective cohort study to determine whether concomitant distal radioulnar joint instability or scapholunate dissociation negatively influence patient-related outcomes in these patients. The primary outcome was the patient-reported wrist/hand evaluation at 6 and 12 months after surgery. Out of 62 patients, 58% and 27% had intraoperative distal radioulnar joint instability and scapholunate dissociation, respectively. No significant differences were found in patient-reported scores at follow-up between patients with stable and unstable distal radioulnar joints, nor between patients with and without scapholunate dissociation. Sixty-three per cent of patients with an unstable distal radioulnar joint during surgery were stable on retesting after 6 months. Our study suggests that a wait-and-see policy in these patients therefore seems reasonable.Level of evidence: III.

Use of Generalizability Theory Evaluating Comparative Reliability of the Scapholunate Interval Measurement With X-ray, CT, and US

RATIONALE AND OBJECTIVES

There is no universally accepted standard technique for measuring the scapholunate interval and no specific sources of measurement error have been identified. We aimed to establish a set of normal radiological criteria for the scapholunate interval that could be used in comparative studies of wrist pathology to determine interobserver reliability and to identify potential errors that might influence measurements.

MATERIALS AND METHODS

A total of 60 healthy volunteers participated in the study. Scapholunate interval was measured by three independent observers using X-ray, CT, and US in four positions, including neutral, fist, radial and ulnar deviation. Inter-observer reliability was tested using intraclass correlation coefficient. Generalizability theory was applied to evaluate specific sources of measurement error related to participant, observer, imaging modality and measurement position.

RESULTS

In neutral position, the scapholunate interval measured by X-ray, CT, and US was 3.1 mm, 3.5 mm and 3.5 mm respectively. The interval remained constant during fist and radial deviation but decreased during ulnar deviation. Correlation coefficients ranged from 0.874 to 0.907 for X-ray, 0.773-0.881 for CT and 0.964-0.979 for US. In the generalizability study, the participant x modality x position interaction accounted for the largest proportion of total variance (29%).

CONCLUSION

X-ray, CT, and US are reliable modalities for measuring the scapholunate interval, with US having the highest reliability. Participant and position factors may independently contribute to measurement error. Therefore, standardized measurement positions are recommended to obtain reliable measurement results.

Kinematic 4D CT case-control study of wrist in dart throwing motion "in vivo": comparison with other maneuvers

OBJECTIVES

To compare the diagnostic performance of scapholunate gap (SLG) measurements acquired with dart throwing (DT), radio-ulnar deviation (RUD), and clenching fist (CF) maneuvers on 4D CT for the identification of scapholunate instability.

METHODS

In this prospective study, 47 patients with suspected scapholunate interosseous ligament (SLIL) tears were evaluated from March 2015 to March 2020 with semiautomatic quantitative analysis on 4D CT. Five parameters (median, maximal value, range, and coefficient of variation) for SLG, lunocapitate angle (LCA), and radioscaphoid angle (RSA) obtained during DT maneuver were evaluated in patients with and without SLIL tears. CT arthrography was used as the gold standard for the SLIL status. The SLG values obtained were also compared with those obtained during CF and RUD maneuvers.

RESULTS

Significant differences in all SLG- and LCA-derived parameters are found between patients with and without SLIL tears with DT (p < 0.003). The best diagnostic performance for the diagnosis of SLIL tears was obtained with median and maximal SLG values (sensitivity and specificity of 86-89% and 95%) and with maximal and range LCA values (sensitivity and specificity of 86% and 74%). No significant differences were observed for RSA values (p > 0.275). The SLG range obtained with DT maneuver was the only dynamic parameter statistically different between patients with partial and complete torn SLIL (p = 0.037).

CONCLUSION

4D CT of the wrist during DT showed a similar performance than RUD and a better performance than CF for the differentiation between patients with and without SLIL tears.

KEY POINTS

• Four-dimensional computed tomography can dynamically assess scapholunate instability. • The best results for differentiating between patients with and without SLIL tears were obtained with SLG median and maximal values. • The dart throwing and radio-ulnar deviation maneuvers yielded the best results for the dynamic evaluation of scapholunate instability.

Interdisciplinary consensus statements on imaging of scapholunate joint instability

Objectives

The purpose of this agreement was to establish evidence-based consensus statements on imaging of scapholunate joint (SLJ) instability by an expert group using the Delphi technique.

Methods

Nineteen hand surgeons developed a preliminary list of questions on SLJ instability. Radiologists created statements based on the literature and the authors’ clinical experience. Questions and statements were revised during three iterative Delphi rounds. Delphi panellists consisted of twenty-seven musculoskeletal radiologists. The panellists scored their degree of agreement to each statement on an eleven-item numeric scale. Scores of ‘0’, ‘5’ and ‘10’ reflected complete disagreement, indeterminate agreement and complete agreement, respectively. Group consensus was defined as a score of ‘8’ or higher for 80% or more of the panellists.

Results

Ten of fifteen statements achieved group consensus in the second Delphi round. The remaining five statements achieved group consensus in the third Delphi round. It was agreed that dorsopalmar and lateral radiographs should be acquired as routine imaging work-up in patients with suspected SLJ instability. Radiographic stress views and dynamic fluoroscopy allow accurate diagnosis of dynamic SLJ instability. MR arthrography and CT arthrography are accurate for detecting scapholunate interosseous ligament tears and articular cartilage defects. Ultrasonography and MRI can delineate most extrinsic carpal ligaments, although validated scientific evidence on accurate differentiation between partially or completely torn or incompetent ligaments is not available.

Conclusions

Delphi-based agreements suggest that standardized radiographs, radiographic stress views, dynamic fluoroscopy, MR arthrography and CT arthrography are the most useful and accurate imaging techniques for the work-up of SLJ instability.

Key Points

• Dorsopalmar and lateral wrist radiographs remain the basic imaging modality for routine imaging work-up in patients with suspected scapholunate joint instability.

• Radiographic stress views and dynamic fluoroscopy of the wrist allow accurate diagnosis of dynamic scapholunate joint instability.

• Wrist MR arthrography and CT arthrography are accurate for determination of scapholunate interosseous ligament tears and cartilage defects.

Imaging of Carpal Instabilities

Background The term “carpal instability” describes different debilitating wrist conditions, in which the carpus is unable to maintain its physiological range of motion and load transfer. Depending on the cause and location of the dysfunction, four groups can be defined: dissociative, non-dissociative, complex, and adaptive carpal instability. As the most common form by far, dissociative carpal instability can further be categorized as dorsal or palmar intercalated segment instability, contingent on the afflicted interosseous ligament.

Method This review article outlines the different entities of carpal instability, their pathophysiology, and their clinical presentation. It further discusses the diagnostic significance of different imaging methods as well as the established treatment options for each form of instability in context with the current literature.

Results and Conclusion Early detection and treatment of carpal instability are essential for preventing carpal osteoarthritis. Traumatic lesions of the scapholunate interosseous ligament are the most frequent cause of instability. They can occur in an isolated fashion or in context with other carpal injuries. While stress imaging and fluoroscopy facilitate the differentiation between dynamic and static forms of carpal instability, only MRI and CT/MR arthrography can directly reveal the extent of ligament discontinuity.

Key Points:

Citation Format

Bilateral scapholunate widening may have a nontraumatic aetiology and progress to carpal instability and osteoarthritis with advancing age

It was hypothesized that bilateral widening of the scapholunate gap is relatively common in the absence of trauma and that it progresses to radiological carpal instability and scapholunate advanced collapse. Electronic files of 1000 patients with bilateral X-rays were studied in retrospect. Wide scapholunate gaps were bilaterally present in 67 and unilaterally in 51 patients. Scapholunate advanced collapse was observed in 26 patients; in nine it was in both wrists. A trauma was recorded in less than half of the patients with a bilateral wide scapholunate gap. Patients with bilateral wide gaps were younger if signs of carpal instability or osteoarthritis were absent. Bilateral scapholunate widening may not be caused by an acute trauma, but may lead to carpal instability and degenerative changes with advancing age.